Note: Descriptions are shown in the official language in which they were submitted.
CA 02750482 2011-08-25
BATTERY-POWERED HAND-HELD ULTRASONIC SURGICAL
CAUTERY CUTTING DEVICE
Field of the Invention
[0001] The present invention relates generally to an ultrasonic cutting device
and, more
particularly, relates to a battery-powered, hand-held, ultrasonic surgical
cautery cutting device.
Description of the Related Art
[0002] Ultrasonic instruments are effectively used in the treatment of many
medical conditions,
such as removal of tissue and cauterization of vessels. Cutting instruments
that utilize ultrasonic
waves generate vibrations with an ultrasonic transducer along a longitudinal
axis of a cutting
blade. By placing a resonant wave along the length of the blade, high-speed
longitudinal
mechanical movement is produced at the end of the blade. These instruments are
advantageous
because the mechanical vibrations transmitted to the end of the blade are very
effective at cutting
organic tissue and, simultaneously, coagulate the tissue using the heat energy
produced by the
ultrasonic frequencies. Such instruments are particularly well suited for use
in minimally
invasive procedures, such as endoscopic or laparoscopic procedures, where the
blade is passed
through a trocar to reach the surgical site.
[0003] For each kind of cutting blade (e.g., length, material, size), there
are one or more
(periodic) driving signals that produce a resonance along the length of the
blade. Resonance
results in movement of the blade tip, which can be optimized for improved
performance during
surgical procedures. However, producing an effective cutting-blade driving
signal is not a trivial
task. For instance, the frequency, current, and voltage applied to the cutting
tool must all be
controlled dynamically, as these parameters change with the varying load
placed on the blade and
with temperature differentials that result from use of the tool.
[0004] FIG. 1 shows a block schematic diagram of a prior-art circuit used for
applying
ultrasonic mechanical movements to an end effector. The circuit includes a
power source 102, a
control circuit 104, a drive circuit 106, a matching circuit 108, a transducer
110, and also
includes a handpiece 112, and a waveguide 114 secured to the handpiece 112
(diagrammatically
illustrated by a dashed line) and supported by a cannula 120. The waveguide
114 terminates to a
blade 116 at a distal end. A clamping mechanism 118, is part of the overall
end effector and
CA 02750482 2011-08-25
exposes and enables the blade portion 116 of the waveguide 114 to make contact
with tissue and
other substances. Commonly, the clamping mechanism 118 is a pivoting arm that
acts to grasp
or clamp onto tissue between the arm and the blade 116. However, in some
devices, the
clamping mechanism 118 is not present.
[0005] The drive circuit 106 produces a high-voltage self-oscillating signal.
The high-voltage
output of the drive circuit 106 is fed to the matching circuit 108, which
contains signal-
smoothing components that, in turn, produce a driving signal (wave) that is
fed to the transducer
110. The oscillating input to the transducer 110 causes the mechanical portion
of the transducer
110 to move back and forth at a magnitude and frequency that sets up a
resonance along the
waveguide 114. For optimal resonance and longevity of the resonating
instrument and its
components, the driving signal applied to the transducer 110 should be as
smooth a sine wave as
can practically be achieved. For this reason, the matching circuit 108, the
transducer 110, and the
waveguide 114 are selected to work in conjunction with one another and are all
frequency
sensitive with and to each other.
[0006] Because a relatively high-voltage (e.g., 100 V or more) is required to
drive a typical
piezoelectric transducer 110, the power source that is available and is used
in all prior-art
ultrasonic cutting devices is an electric mains (e.g., a wall outlet) of,
typically, up to 15A,
120VAC. Therefore, all known ultrasonic surgical cutting devices resemble that
shown in FIGS.
1 and 2 and utilize a countertop box 202 with an electrical cord 204 to be
plugged into the
electrical mains 206 for supply of power. Resonance is maintained by a phase
locked loop
(PLL), which creates a closed loop between the output of the matching circuit
108 and the drive
circuit 106. For this reason, in prior art devices, the countertop box 202
always has contained all
of the drive and control electronics 104, 106 and the matching circuit(s) 108.
A typical retail
price for such boxes is in the tens of thousands of dollars.
[0007] A supply cord 208 delivers a sinusoidal waveform from the box 202 to
the transducer
110 within the handpiece 112 and, thereby, to the waveguide 114. The prior art
devices present a
great disadvantage because the cord 208 has a length, size, and weight that
restricts the mobility
of the operator. The cord 208 creates a tether for the operator and presents
an obstacle for the
operator and those around him/her during any surgical procedure using the
handpiece 112. In
addition, the cord must be shielded and durable and is very expensive.
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[0008] Another disadvantage exists in the prior art due to the frequency
sensitivity of the
matching circuit 108, the transducer 110, and the waveguide 114. By having a
phase-locked-loop
feedback circuit between the output of the matching circuit 108 and the drive
circuit 104, the
matching circuit 108 has always been located in the box 202, near the drive
circuit 108, and
separated from the transducer 110 by the length of the supply cord 208. This
architecture
introduces transmission losses and electrical parasitics, which are common
products of
ultrasonic-frequency transmissions.
[0009] In addition, prior-art devices attempt to maintain resonance at varying
waveguide 114
load conditions by monitoring and maintaining a constant current applied to
the transducer (when
operating with series resonance). However, without knowing the specific load
conditions, the
only predictable relationship between current applied to the transducer 110
and amplitude is at
resonance. Therefore, with constant current, the amplitude of the wave along
the waveguide 114
is not constant across all frequencies. When prior art devices are under load,
therefore, operation
of the waveguide 114 is not guaranteed to be at resonance and, because only
the current is being
monitored and held constant, the amount of movement on the waveguide 114 can
vary greatly.
For this reason, maintaining constant current is not an effective way of
maintaining a constant
movement of the waveguide 114.
[0010] Furthermore, in the prior art, handpieces 112 and transducers 110 are
replaced after a
finite number of uses, but the box 202, which is vastly more expensive than
the handpiece 112, is
not replaced. As such, introduction of new, replacement handpieces 112 and
transducers 110
frequently causes a mismatch between the frequency-sensitive components (108,
110, and 112),
thereby disadvantageously altering the frequency introduced to the waveguide
114. The only
way to avoid such mismatches is for the prior-art circuits to restrict
themselves to precise
frequencies. This precision brings with it a significant increase in cost.
[0011] Therefore, a need exists to overcome the problems associated with the
prior art, for
example, those discussed above.
Summary of the Invention
[0012] Briefly, in accordance with exemplary embodiments, the present
invention includes a
battery powered device that produces high frequency mechanical motion at the
end of a
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waveguide for performing useful work, specifically, to cut and seal tissue
during surgery. A
piezoelectric transducer is used to convert electrical energy into the
mechanical energy that
produces the motion at the end of the waveguide. Particularly, when the
transducer and
waveguide are driven at their composite resonant frequency, a large amount of
mechanical
motion is produced. The circuit components of the present invention include,
among others, a
battery power supply, a control circuit, a drive circuit, and a matching
circuit -- all located within
a handpiece of the ultrasonic cutting device and all operating and generating
waveforms from
battery voltages. The components are selected to convert electrical energy
from the battery
power supply into a high voltage AC waveform that drives the transducer.
Ideally, the frequency
of this waveform is substantially the same as the resonant frequency of the
waveguide and
transducer. The magnitude of the waveform is selected to be a value that
produces the desired
amount of mechanical motion.
[0013] Advantageously, the present invention, according to several
embodiments, allows
components of the device to be removed, replaced, serviced, and/or
interchanged. Some
components are "disposable," which, as used herein, means that the component
is used for only
one procedure and is then discarded. Still other components are "reusable,"
which, as used
herein, means that the component can be sterilized according to standard
medical procedures and
then used for at least a second time. As will be explained, other components
are provided with
intelligence that allows them to recognize the device to which they are
attached and to alter their
function or performance depending on several factors.
[0014] The invention provides a cordless hand-held ultrasonic cautery cutting
device that
overcomes the hereinafore-mentioned disadvantages of the heretofore-known
devices and
methods of this general type and that require disposal of and prevent
advantageous reuse of
costly components.
[0015] With the foregoing and other objects in view, there is provided, in
accordance with the
invention, a battery-powered, modular surgical device includes an electrically
powered surgical
instrument operable to surgically interface with human tissue and a handle
assembly connected to
the surgical instrument. The handle assembly has a removable hand grip and a
handle body. The
hand grip is shaped to permit handling of the surgical device by one hand of
an operator, has an
upper portion and a cordless internal battery assembly that powers the
surgical instrument. The
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internal battery assembly has at least one energy storage cell. The handle
body is operable to
removably connect at least the upper portion of the hand grip thereto and
create an aseptic seal
around at least a portion of the hand grip when connected thereto and
electrically couple the
internal battery assembly of the hand grip to the surgical instrument and
thereby power the
surgical instrument for interfacing surgically with the human tissue.
[0016] With the objects of the invention in view, there is also provided a
battery-powered,
modular surgical device comprising an electrically powered surgical end
effector assembly
operable to surgically interface with human tissue and a removable hand grip
shaped to permit
handling of the surgical device by one hand of an operator. The removable hand
grip includes at
least one reusable battery electrically coupled to the surgical end effector
assembly to power and
thereby cause the surgical end effector assembly to operate and is removably
secured to the
surgical end effector assembly such that the at least one battery is
selectively exposed to the
surgical environment when removed therefrom.
[0017] With the objects of the invention in view, there is also provided a
removable battery
assembly of a battery-powered surgical device having an electrically powered
surgical instrument
operable to surgically interface with human tissue comprise a battery body
outer shell having an
upper portion, a lower portion, and defining a shell interior. The battery
body outer shell is a
hand grip of the surgical device when secured to the surgical instrument, is
shaped to permit
handling of the surgical device by one hand of an operator, has, in the shell
interior, a cordless
rechargeable battery that powers the surgical instrument, has an upper portion
shaped to
removably connect to a portion of the surgical instrument and create an
aseptic seal around at
least a part of the upper portion when connected thereto and be selectively
exposed to the
surgical environment when removed therefrom, and has exterior conductors
electrically coupled
to the cordless rechargeable battery and positioned to supply at least power
to operate the surgical
instrument.
[0018] In accordance with another feature of the invention, at least one of
the surgical
instrument, the removable hand grip, and the handle body is disposable.
[0019] In accordance with a further feature of the invention, the surgical
instrument is
comprised of a surgical cautery and cutting end effector assembly.
CA 02750482 2015-04-08
[0020] In accordance with an added feature of the invention, the surgical
cautery and cutting end
effector assembly is an ultrasonic surgical cautery and cutting end effector
assembly.
[0021] In accordance with an additional feature of the invention, the battery
assembly is
rechargeable.
[0022] In accordance with yet another feature of the invention, the at least
one energy storage
cell is a Lithium-based battery cell.
[0023] In accordance with a concomitant feature of the invention, the surgical
instrument is
comprised of at least one pivoting jaw member and a cutting blade opposing the
jaw member.
[0024] Although the invention is illustrated and described herein as embodied
in a
cordless, battery-powered, hand-held, ultrasonic, surgical, cautery cutting
device, it is,
nevertheless, not intended to be limited to the details shown, and the
disclosed
embodiments are merely exemplary of the invention which can be embodied in
various
forms.
[0025] While the specification concludes with claims defining the features of
the invention
that are regarded as novel, it is believed that the invention will be better
understood from a
consideration of the following description in conjunction with the drawing
figures, in
which like reference numerals are carried forward. Accordingly, the apparatus
components
and method steps have been represented where appropriate by conventional
symbols in the
drawings, showing only those specific details that are pertinent to
understanding the
embodiments of the present invention so as not to obscure the disclosure with
details that
will be readily apparent to those of ordinary skill in the art having the
benefit of the
description herein. The figures of the drawings are not drawn to scale.
[0026] Other features that are considered as characteristic for the invention
are set forth in the
appended claims. As required, detailed embodiments of the present invention
are disclosed
herein; however, it is to be understood that the disclosed embodiments are
merely exemplary
of the invention, which can be embodied in various forms. Therefore, specific
structural and
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CA 02750482 2011-08-25
functional details disclosed herein are not to be interpreted as limiting, but
merely as a basis for
the claims and as a representative basis for teaching one of ordinary skill in
the art to variously
employ the present invention in virtually any appropriately detailed
structure. Further, the terms
and phrases used herein are not intended to be limiting; but rather, to
provide an understandable
description of the invention.
Detailed Description of the Drawings
[0027] The accompanying figures, where like reference numerals refer to
identical or
functionally similar elements throughout the separate views and which together
with the detailed
description below are incorporated in and form part of the specification,
serve to further illustrate
various embodiments and to explain various principles and advantages all in
accordance with the
present invention.
[0028] FIG. 1 is a diagrammatic illustration of components of a prior-art
ultrasonic cutting
device with separate power, control, drive and matching components in block
diagram form.
[0029] FIG. 2 is a diagram illustrating the prior-art ultrasonic cutting
device of FIG. 1.
[0030] FIG. 3 is an elevational view of a left side of an ultrasonic surgical
cautery assembly in
accordance with an exemplary embodiment of the present invention.
[0031] FIG. 4 is a perspective view from above a corner of a battery assembly
in accordance
with an exemplary embodiment of the present invention.
[0032] FIG. 5 is an elevational left side view of a transducer and generator
assembly in
accordance with an exemplary embodiment of the present invention.
[0033] FIG. 6 is a schematic block diagram of the cordless, battery-powered,
hand-held,
ultrasonic, surgical, cautery cutting device in accordance with an exemplary
embodiment of the
present invention.
[0034] FIG. 7 is a schematic block diagram of a battery assembly of the device
of FIGS. 3 and
4 in accordance with an exemplary embodiment of the present invention.
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[0035] FIG. 8 is a schematic block diagram of a handle assembly of the device
of FIGS. 3 and
4 in accordance with an exemplary embodiment of the present invention.
[0036] FIG. 9 is a schematic block diagram of the transducer and generator
assembly of the
device of FIGS. 3 to 5 in accordance with an exemplary embodiment of the
present invention.
[0037] FIG. 10 is a schematic block diagram of the generator of FIG. 9 in
accordance with an
exemplary embodiment of the present invention.
[0038] FIG. 11 is a schematic block diagram of the battery controller of the
device of FIGS. 3
and 4 in accordance with an exemplary embodiment of the present invention.
[0039] FIG. 12 is a schematic block diagram illustrating an electrical
communicating
relationship between the battery assembly and the transducer and generator
assembly of the
device of FIGS. 3 to 5 in accordance with an exemplary embodiment of the
present invention.
[0040] FIG. 13 is graph illustrating a square waveform input to a matching
circuit in
accordance with an exemplary embodiment of the present invention.
[0041] FIG. 14 is graph illustrating a sinusoidal waveform output from a
matching circuit in
accordance with an exemplary embodiment of the present invention.
[0042] FIG. 15 is a diagrammatic illustration of the affect that a resonant
sine wave input to a
transducer has on a waveguide of the ultrasonic cutting device in accordance
with an exemplary
embodiment of the present invention with the sinusoidal pattern shown
representing the
amplitude of axial motion along the length of the waveguide.
[0043] FIG. 16 is a fragmentary, schematic circuit diagram of an elemental
series circuit model
for a transducer in accordance with an exemplary embodiment of the present
invention.
[0044] FIG. 17 is a fragmentary, schematic circuit diagram of an inventive
circuit with the
circuit of FIG. 16 and is useful for monitoring a motional current of a
transducer in accordance
with an exemplary embodiment of the present invention.
[0045] FIG. 18 is a fragmentary, schematic circuit diagram of an elemental
parallel circuit
model of a transducer in accordance with an exemplary embodiment of the
present invention.
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[0046] FIG. 19 is fragmentary, schematic circuit diagram of an inventive
circuit with the circuit
of FIG. 20 and is useful for monitoring the motional current of a transducer
in accordance with
an exemplary embodiment of the present invention.
[0047] FIG. 20 is a fragmentary, schematic circuit diagram of an inventive
circuit with the
circuit of FIG. 16 and is useful for monitoring the motional current of a
transducer in accordance
with an exemplary embodiment of the present invention.
[0048] FIG. 21 is a fragmentary, schematic circuit diagram of an inventive
circuit with the
circuit of FIG. 18 and is useful for monitoring the motional voltage of a
transducer in accordance
with an exemplary embodiment of the present invention.
[0049] FIG. 22 is a schematic circuit diagram modeling a direct digital
synthesis technique
implemented in accordance with an exemplary embodiment of the present
invention.
[0050] FIG. 23 is a graph illustrating an exemplary direct output of a digital-
to-analog
converter (DAC) positioned above a filtered output of the DAC in accordance
with an exemplary
embodiment of the present invention.
[0051] FIG. 24 is a graph illustrating an exemplary direct output of a digital-
to-analog
converter (DAC) with a tuning word shorter than the tuning word used to
produce the graph of
FIG. 23 positioned above a filtered output of the DAC using the same shortened
tuning word in
accordance with an exemplary embodiment of the present invention.
[0052] FIG. 25 is a graph illustrating an exemplary direct output of a digital-
to-analog
converter (DAC) with a tuning word longer than the tuning word used to produce
the graph of
FIG. 23 positioned above a filtered output of the DAC using the longer tuning
word in
accordance with an exemplary embodiment of the present invention.
[0053] FIG. 26 is block circuit diagram of exemplary components comprising the
current
control loop in accordance with an exemplary embodiment of the present
invention.
[0054] FIG. 27 is a block circuit diagram of the device of FIG. 3 in
accordance with an
exemplary embodiment of the present invention.
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[0055] FIG. 28 is a perspective view from above the front of the battery
assembly of FIG. 4 in
accordance with an exemplary embodiment of the present invention.
[0056] FIG. 29 is a fragmentary, perspective view from a left side of the of
the battery
assembly of FIG. 4 with one half of the shell removed exposing an underside of
a multi-lead
battery terminal and an interior of the remaining shell half in accordance
with an exemplary
embodiment of the present invention.
[0057] FIG. 30 is a fragmentary, perspective view from a right side of the
battery assembly of
FIG. 4 with one half of the shell removed exposing the circuit board connected
to the multi-lead
battery terminal in accordance with an exemplary embodiment of the present
invention.
[0058] FIG. 31 is an elevated perspective view of the battery assembly of FIG.
4 with both
halves of the shell removed exposing battery cells coupled to multiple circuit
boards which are
coupled to the multi-lead battery terminal in accordance with an exemplary
embodiment of the
present invention.
[0059] FIG. 32 is an elevated perspective view of the battery assembly shown
in FIG. 31 with
one half of the shell in place in accordance with an exemplary embodiment of
the present
invention.
[0060] FIG. 33 is an elevated perspective view of the battery assembly of FIG.
4 showing a
catch located on a rear side of the battery assembly in accordance with an
exemplary embodiment
of the present invention.
[0061] FIG. 34 is an underside perspective view of the handle assembly of FIG.
3 exposing a
multi-lead handle terminal assembly and a receiver for mating with the battery
assembly of FIG.
4 in accordance with an exemplary embodiment of the present invention.
[0062] FIG. 35 is a close-up underside perspective view of the handle assembly
of FIG. 3
exposing a multi-lead handle terminal assembly and a receiver for mating with
the battery
assembly of FIG. 4 in accordance with an exemplary embodiment of the present
invention.
CA 02750482 2011-08-25
[0063] FIG. 36 is an underside perspective view illustrating an initial mating
connection
between the handle assembly and the battery assembly in accordance with an
exemplary
embodiment of the present invention.
[0064] FIG. 37 is a perspective view of the battery assembly fully connected
to the handle
assembly in accordance with an exemplary embodiment of the present invention.
[0065] FIG. 38 is a close-up perspective view of the exterior surface of the
battery assembly of
FIG. 4 illustrating a release mechanism for coupling the battery assembly to
the handle assembly
in accordance with an exemplary embodiment of the present invention.
[0066] FIG. 39 is a close-up perspective view of the multi-lead handle
terminal assembly in
accordance with an exemplary embodiment of the present invention.
[0067] FIG. 40 is a close-up perspective view of the ultrasonic surgical
cautery assembly of
FIG. 1 with one half the shell of the handle assembly removed providing a
detailed view of the
mating position between the multi-lead handle terminal assembly and the multi-
lead handle
battery assembly in accordance with an exemplary embodiment of the present
invention.
[0068] FIG. 41 is a fragmentary, cross-sectional and perspective view of a
pressure valve of the
battery assembly of FIG. 3 in accordance with an exemplary embodiment of the
present invention
viewed from a direction inside the battery assembly.
[0069] FIG. 42 is a fragmentary, cross-sectional view of the pressure valve of
FIG. 41 viewed
from a side of the valve.
[0070] FIG. 43 is a perspective view of the pressure valve of FIG. 41
separated from the
battery assembly.
[0071] FIG. 44 is a graph illustrating pressure states of the pressure valve
of FIG. 41 in
accordance with an exemplary embodiment of the present invention.
[0072] FIG. 45 is an elevational exploded view of the left side of the
ultrasonic surgical cautery
assembly of FIG. 3 showing the left shell half removed from the battery
assembly and the left
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shell half removed from the handle assembly in accordance with an exemplary
embodiment of
the present invention.
[0073] FIG. 46 is an elevational right-hand view of the handle assembly of
FIG. 3 with the
right shell half removed showing controls in accordance with an exemplary
embodiment of the
present invention.
[0074] FIG. 47 is elevational close-up view of the handle assembly of FIG. 3
with the left shell
half removed showing the trigger of FIG. 46 in accordance with an exemplary
embodiment of the
present invention.
[0075] FIG. 48 is an elevational close-up view of a two-stage switch in the
handle assembly
activated by the button of FIG. 46 in accordance with an exemplary embodiment
of the present
invention.
[0076] FIG. 49 is an elevational view of an example of a two-stage switch of
FIG. 48 in
accordance with an exemplary embodiment of the present invention.
[0077] FIG. 50 is an elevational side view of the TAG of FIG. 3 in accordance
with an
exemplary embodiment of the present invention.
[0078] FIG. 51 is an elevational underside view of the TAG of FIG. 50 in
accordance with an
exemplary embodiment of the present invention.
[0079] FIG. 52 is an elevational upper view of the TAG of FIG. 50 in
accordance with an
exemplary embodiment of the present invention.
[0080] FIG. 53 is an elevational view of the TAG of FIG. 50 with an upper
cover removed
revealing generator circuitry in accordance with an exemplary embodiment of
the present
invention.
[0081] FIG. 54 is an elevational underside view of the TAG of FIG. 50 with an
underside cover
removed revealing electrical coupling between the generator and the transducer
in accordance
with an exemplary embodiment of the present invention.
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[0082] FIG. 55 is a perspective underside view of the TAG of FIG. 50 with an
underside cover
of the TAG removed and the transducer cover removed revealing components of
the transducer
in accordance with an exemplary embodiment of the present invention.
[0083] FIG. 56 is an elevational left side view of the handle assembly and the
TAG, illustrating
a coupling alignment between the handle assembly and the TAG in accordance
with an
exemplary embodiment of the present invention.
[0084] FIG. 57 is an elevational exploded view of the left side of the
ultrasonic surgical cautery
assembly of FIG. 3 showing the left shell half removed from handle assembly
exposing a device
identifier communicatively coupled to the multi-lead handle terminal assembly
in accordance
with an exemplary embodiment of the present invention.
[0085] FIG. 58 is a perspective close-up view of the transducer with the outer
shell removed in
accordance with an exemplary embodiment of the present invention.
[0086] FIG. 59 is a perspective close-up view of the coupling relationship
between the catch on
the battery assembly and the receiver on the handle assembly as well as the
sealing relationship
between the multi-lead battery terminal assembly and the multi-lead handle
terminal assembly in
accordance with an exemplary embodiment of the present invention.
[0087] FIG. 60 is a perspective close-up transparent view of the sealing
gasket of FIG. 59 in
accordance with an exemplary embodiment of the present invention.
[0088] FIG. 61 is a perspective partial view of the handle assembly with the
right-hand cover
half removed, exposing a near-over-centering trigger mechanism in accordance
with an
exemplary embodiment of the present invention.
[0089] FIG. 62 is a perspective partial view of the near-over-centering
trigger mechanism of
FIG. 61, with the trigger slightly depressed, in accordance with an exemplary
embodiment of the
present invention.
[0090] FIG. 63 is a perspective partial view of the near-over-centering
trigger mechanism of
FIG. 61, with the trigger depressed, in accordance with an exemplary
embodiment of the present
invention.
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[0091] FIG. 64 is a perspective partial view of the near-over-centering
trigger mechanism of
FIG. 61, with the trigger fully depressed, in accordance with an exemplary
embodiment of the
present invention.
[0092] FIG. 65 is a perspective fragmentary view of a rotational lockout
member and blade
adjacent, but not engaging with, a waveguide assembly rotation-prevention
wheel, in accordance
with an exemplary embodiment of the present invention.
[0093] FIG. 66 is a perspective fragmentary view of the rotational lockout
member and blade
of FIG. 65 engaging the waveguide assembly rotation-prevention wheel in
accordance with an
exemplary embodiment of the present invention.
[0094] FIG. 67 is a perspective fragmentary view of a two-stage button in an
undepressed state
and in physical communication with the rotational lockout member of FIG. 65 in
accordance
with an exemplary embodiment of the present invention.
[0095] FIG. 68 is a perspective fragmentary view of the two-stage button in a
first depressed
state and physically engaging the rotational lockout member of FIG. 65 in
accordance with an
exemplary embodiment of the present invention.
[0096] FIG. 69 is a perspective fragmentary view of the two-stage button of
FIG. 68 in a
second depressed state and fully engaging the rotational lockout member of
FIG. 65, which, in
turn, is engaging the waveguide assembly rotation-prevention wheel in
accordance with an
exemplary embodiment of the present invention.
[0097] FIG. 70 is a perspective fragmentary view of a rotational lockout
member and dual
blades adjacent, but not engaging with, a waveguide assembly rotation-
prevention wheel, in
accordance with an exemplary embodiment of the present invention.
[0098] FIG. 71 is a perspective fragmentary view of the rotational lockout
member and dual
blades of FIG. 70 engaging the waveguide assembly rotation-prevention wheel in
accordance
with an exemplary embodiment of the present invention.
[0099] FIG. 72 and FIG. 72A show a process flow diagram illustrating a start-
up procedure in
accordance with an exemplary embodiment of the present invention.
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[00100] FIG. 73 is a fragmentary, enlarged perspective view of an exemplary
embodiment of an
end effector according to the invention from a distal end with a jaw in an
open position;
[00101] FIG. 74 is a fragmentary, enlarged perspective view of the end
effector of FIG. 73 from
below with an outer tube removed;
[00102] FIG. 75 is a fragmentary, enlarged cross-sectional and perspective
view of the end
effector of FIG. 73 from below with the section taken transverse to the jaw-
operating plane
through the waveguide;
[00103] FIG. 76 is a fragmentary, enlarged side elevational view of the end
effector of FIG. 73
with the outer tube removed;
[00104] FIG. 77 is a fragmentary, enlarged cross-sectional side view of the
end effector of FIG.
73 with the section taken parallel to the jaw-operating plane with the
waveguide removed;
[00105] FIG. 78 is a fragmentary, enlarged, side elevational view of the end
effector of FIG. 73;
[00106] FIG. 79 is a fragmentary, enlarged, side elevational view of the end
effector of FIG. 78
with the jaw in a substantially closed position;
[00107] FIG. 80 is a fragmentary, enlarged, perspective view of the end
effector of FIG. 73 with
the jaw in the substantially closed position;
[00108] FIG. 81 is a fragmentary, enlarged cross-sectional side view of the
end effector of FIG.
73 with the section taken in the jaw-operating plane;
[00109] FIG. 82 is an enlarged perspective view of a coupling spool of the end
effector of FIG.
73;
[00110] FIG. 83 is a fragmentary, enlarged, cross-sectional view of the end
effector of FIG. 73
with the section taken orthogonal to the longitudinal axis of the waveguide at
a jaw pivot;
[00111] FIG. 84 is an enlarged, perspective view of a jaw insert of the end
effector of FIG. 73
viewed from below a distal end;
CA 02750482 2011-08-25
[00112] FIG. 85 is an enlarged, cross-sectional and perspective view of a left
portion of the jaw
insert of FIG. 84 seated within a left portion of the jaw of FIG. 73 viewed
from below a proximal
end;
[00113] FIG. 86 is a fragmentary, enlarged, perspective view of a TAG
attachment dock and a
waveguide attachment dock of the handle assembly of FIG. 46 with a right half
of the handle
body, a rotation-prevention wheel, and a spring and bobbin of the jaw force-
limiting assembly
removed;
[00114] FIG. 87 is a fragmentary, enlarged, perspective view of the handle
assembly of FIG. 86
with an outer tube removed and only a right half of the rotation-prevention
wheel removed; and
[00115] FIG. 88 is a perspective view of a torque wrench according to an
exemplary
embodiment of the invention.
Detailed Description of the Embodiments
[00116] It is to be understood that the disclosed embodiments are merely
exemplary of the
invention, which can be embodied in various forms. Therefore, specific
structural and functional
details disclosed herein are not to be interpreted as limiting, but merely as
a basis for the claims
and as a representative basis for teaching one skilled in the art to variously
employ the present
invention in virtually any appropriately detailed structure. Further, the
terms and phrases used
herein are not intended to be limiting; but rather, to provide an
understandable description of the
invention.
[00117] Before the present invention is disclosed and described, it is to be
understood that the
terminology used herein is for the purpose of describing particular
embodiments only and is not
intended to be limiting. In this document, the terms "a" or "an", as used
herein, are defined as
one or more than one. The term "plurality," as used herein, is defined as two
or more than two.
The term "another," as used herein, is defined as at least a second or more.
The terms
"including" and/or "having," as used herein, are defined as comprising (i.e.,
open language). The
term "coupled," as used herein, is defined as connected, although not
necessarily directly, and not
necessarily mechanically. Relational terms such as first and second, top and
bottom, and the like
may be used solely to distinguish one entity or action from another entity or
action without
16
CA 02750482 2011-08-25
necessarily requiring or implying any actual such relationship or order
between such entities or
actions. The terms "comprises," "comprising," or any other variation thereof
are intended to
cover a non-exclusive inclusion, such that a process, method, article, or
apparatus that comprises
a list of elements does not include only those elements but may include other
elements not
expressly listed or inherent to such process, method, article, or apparatus.
An element proceeded
by "comprises ... a" does not, without more constraints, preclude the
existence of additional
identical elements in the process, method, article, or apparatus that
comprises the element.
[00118] As used herein, the term "about" or "approximately" applies to all
numeric values,
whether or not explicitly indicated. These terms generally refer to a range of
numbers that one of
skill in the art would consider equivalent to the recited values (i.e., having
the same function or
result). In many instances these terms may include numbers that are rounded to
the nearest
significant figure. In this document, the term "longitudinal" should be
understood to mean in a
direction corresponding to an elongated direction of the object being
described.
[00119] It will be appreciated that embodiments of the invention described
herein may be
comprised of one or more conventional processors and unique stored program
instructions that
control the one or more processors to implement, in conjunction with certain
non-processor
circuits and other elements, some, most, or all of the functions of ultrasonic
cutting devices
described herein. The non-processor circuits may include, but are not limited
to, signal drivers,
clock circuits, power source circuits, and user input and output elements.
Alternatively, some or
all functions could be implemented by a state machine that has no stored
program instructions, or
in one or more application specific integrated circuits (ASICs) or field-
programmable gate arrays
(FPGA), in which each function or some combinations of certain of the
functions are
implemented as custom logic. Of course, a combination of these approaches
could also be used.
Thus, methods and means for these functions have been described herein.
[00120] The terms "program," "software application," and the like as used
herein, are defined as
a sequence of instructions designed for execution on a computer system. A
"program,"
"computer program," or "software application" may include a subroutine, a
function, a
procedure, an object method, an object implementation, an executable
application, an applet, a
servlet, a source code, an object code, a shared library/dynamic load library
and/or other
sequence of instructions designed for execution on a computer system.
17
CA 02750482 2011-08-25
[00121] The present invention, according to one embodiment, overcomes problems
with the
prior art by providing a lightweight, hand-held, cordless, battery-powered,
surgical cautery
cutting device that is powered by and controlled with components that fit
entirely within a handle
of the device. The hand-held device allows a surgeon to perform ultrasonic
cutting and/or
cauterizing in any surgical procedure without the need for external power and,
particularly,
without the presence of cords tethering the surgeon to a stationary object and
constricting the
range of movement of the surgeon while performing the surgical procedure.
[00122] ULTRASONIC SURGICAL DEVICE
[00123] Described now is an exemplary apparatus according to one embodiment of
the present
invention. Referring to FIG. 3, an exemplary cordless ultrasonic surgical
cautery assembly 300 is
shown. The inventive assembly 300 can be described as including three main
component parts:
(1) a battery assembly 301; (2) a handle assembly 302 with an ultrasonic
cutting blade and
waveguide assembly 304 (only a proximal portion of which is illustrated in
FIG. 3); and (3) a
transducer-and-generator ("TAG") assembly 303. The handle assembly 302 and the
ultrasonic
cutting blade and waveguide assembly 304 are pre-coupled but rotationally
independent from one
another. The battery assembly 301, according to one exemplary embodiment, is a
rechargeable,
reusable battery pack with regulated output. In some cases, as is explained
below, the battery
assembly 301 facilitates user-interface functions. The handle assembly 302 is
a disposable unit
that has bays or docks for attachment to the battery assembly 301, the TAG
assembly 303, and
the ultrasonic cutting blade and waveguide assembly 304. The handle assembly
302 also houses
various indicators including, for example, a speaker/buzzer and activation
switches.
[00124] The TAG assembly 303 is a reusable unit that produces high frequency
mechanical
motion at a distal output. The TAG assembly 303 is mechanically coupled to the
ultrasonic
cutting blade and waveguide assembly 304 during operation of the device and
produces
movement at the distal output, i.e., the cutting blade. In one embodiment, the
TAG assembly 303
also provides a visual user interface, such as, through a red/green/blue (RGB)
LED. As such, a
visual indicator of the battery status is uniquely not located on the battery
and is, therefore,
remote from the battery.
18
CA 02750482 2011-08-25
[00125] The present invention's ability to provide all of the necessary
components of an
ultrasonic cutting tool in a hand-held package provides a great advantage over
prior-art devices,
which devices house substantially all of the device components within a very
expensive and
heavy desktop box 202, as shown in FIG. 2, and include an expensive tether 208
between the
device's handpiece 112 and the desktop box 202, which, most significantly, is
bulky and
interferes with the surgeon's movements.
[00126] In accordance with the present invention, the three components of the
handheld
ultrasonic surgical cautery assembly 300 are advantageously quickly
disconnectable from one or
more of the others. Each of the three components of the system is sterile and
can be maintained
wholly in a sterile field during use. Because each portion can be separated
from one or more of
the other components, the present invention can be composed of one or more
portions that are
single-use items (i.e., disposable) and others that are multi-use items (i.e.,
sterilizable for use in
multiple surgical procedures). FIGS. 4 and 5 show the battery assembly 301 and
TAG assembly
303 components, respectively, separate from the overall composite assembly
shown in FIG. 3.
The details of each of the components are shown and described throughout the
remainder of the
specification. These details include, inter alia, physical aspects of each
component separate and
as part of the handheld ultrasonic surgical cautery assembly 300, electronic
functionality and
capability of each component separate and as part of the overall assembly 300,
and methods of
use, assembly, sterilization, and others of each component separate and as
part of the overall
assembly 300. In accordance with an additional embodiment of the present
invention, each of
the components 301, 302/304, 303 is substantially equivalent in overall
weight. Each of these
components 301, 302/304, 303 is balanced so that they weigh substantially the
same. This,
combined with a triangular assembly configuration, makes the overall handheld
ultrasonic
surgical cautery assembly 300 advantageously provided with a center of balance
that provides a
very natural and comfortable feel to the user operating the device. That is,
when held in the hand
of the user, the overall assembly 300 does not have a tendency to tip forward
or backward or
side-to-side but remains relatively and dynamically balanced so that the
waveguide is held
parallel to the ground with very little effort from the user. Of course, the
instrument can be
placed in non-parallel angles to the ground just as easily.
19
CA 02750482 2011-08-25
[00127] FIG. 6 provides a general block schematic diagram illustrating the
communicative
coupling between the battery assembly 301, the handle assembly 302, and the
TAG assembly
303. FIG. 6 also shows various power and communication signal paths 601a-n
between the
battery assembly 301 and the handle assembly 302. The handle assembly 302
provides
additional power and communication signal paths 602a-n that continue on to the
TAG assembly
303. These power and communication signal paths 601a-n facilitate operation
of:
1. a buzzer, e.g., audio frequency signal, which provides an audible user
interface;
2. a minimum button, e.g., 0 to 3.3 V and 0 to 25mA input signal, which is
a user
interface to activate ultrasound output at minimum amplitude;
3. a maximum button, e.g., 0 to 3.3 V and 0 to 25mA, which is a user
interface to
activate ultrasound output at maximum amplitude;
4. a first output voltage (Vout), e.g., 0 to 10 Volt and 0 to 6A output,
from the
battery assembly 301 to the TAG assembly 303 and provides power to the TAG
assembly 303 to generate a transducer drive signal;
5. a ground or system common connection;
6. a second output voltage (Vbatt), which is a voltage output from battery
for
providing power for the system;
7. a first communication line (Comm+), which provides differential half
duplex
serial communications between the battery assembly 301 and the TAG assembly
303;
8. a second communication line (Comm-), which provides differential half
duplex
serial communications between the battery assembly 301 and the TAG assembly
303; and
9. a present line, which, when connected to the handle assembly 302,
activates
power in the battery assembly 301 and, thereby, to the entire system.
[00128] In accordance with an embodiment of the present invention, the
above-described
power and communication signal paths 601a-n are provided through a flex
circuit that spans
between a first multi-lead handle terminal assembly on the handle assembly 302
(where the
battery assembly 301 electrically couples to the handle assembly 302) and a
second multi-lead
CA 02750482 2011-08-25
handle terminal assembly on the handle assembly 302 (where the TAG assembly
303 electrically
couples to the handle assembly 302).
[00129] I. BATTERY ASSEMBLY
[00130] FIG. 7 provides a general block schematic diagram illustrating battery
assembly 301
and the internal components included therein. The battery assembly 301
generally includes one
or more battery cells 701, a battery protection circuit 702, and a battery
controller 703. Various
power and signal paths 704a-n run between the battery cells 701 and the
battery protection circuit
702. Power and communication signal paths 706a-n run between the battery
protection circuit
702 and the battery controller 703. The power and signal paths 704a-n and 706a-
n can be simple
direct connections between components or can include other circuit elements
not shown in the
figures. The power and communication signal paths 706a-n include, among
others:
1. a SMBus clock signal (SCLK), which is used for communications between
the
battery controller 703 and the battery fuel gauge/protection circuit 702;
2. a SMBus data signal (SDAT), which is used for communications between the
battery controller 703 and the battery fuel gauge/protection circuit 702; and
3. an enable switch that turns off the battery controller 703 when the
battery
assembly 301 is in a charger by removing power to the switching power supply
within the battery controller 703 once grounded.
[00131] a. Battery Cells
[00132] The battery cells 701 include, in one embodiment, a 4-cell lithium-ion
polymer (LiPoly)
battery. There is, of course, no limit to the number of cells that can be used
and no requirement
that the cells be LiPoly type. Advantageously, manufacturers can produce
LiPoly batteries in
almost any shape that is necessary. These types of batteries, however, must be
carefully
controlled during the charging process, as overcharging LiPoly batteries
quickly causes damages
to the cells. Therefore, these batteries must be charged carefully. For this
reason, the present
invention utilizes an inventive battery protection circuit 702.
21
CA 02750482 2011-08-25
[00133] b. Battery Protection
[00134] The battery protection circuit 702 controls charging and discharging
of the battery cells
701 and provides battery protection and "fuel gauge" functions, i.e., battery
power monitoring.
More particularly, the battery protection circuit 702 provides over-voltage,
under-voltage, over-
temperature, and over-current monitoring and protection during both the
charging and
discharging stages. If overcharged, LiPoly batteries cannot only be damaged
but can also ignite
and/or vent.
[00135] The "fuel gauge" function of the battery protection circuit 702 limits
the discharge of
voltage and current, both continuous and transient, on the output of the
battery assembly 301.
During charging of the battery cells 701, the fuel gauge can limit the current
level fed to the
battery cells 701. Alternatively, a battery charging unit can perform this
current-limiting
function. The fuel gauge also monitors temperature and shuts down the battery
assembly 301
when a temperature of the battery cells 701 exceeds a given temperature. The
fuel gauge is
further able to determine how much total energy is left in the battery cells
701, to determine how
much previous charge has been received, to determine an internal impedance of
the battery cells
701, to determine current and voltage being output, and more. By using this
data, the present
invention, through use of inventive algorithms, is able to determine the
operational capacity of
the battery cells 701 based in part on the chemical attributes of the battery
cells 701 and, in
particular, to identify when there is not enough battery capacity to safely
perform a surgical
procedure as described in further detail below.
[00136] c. Battery Controller
[00137] FIG. 11 is a general block circuit diagram illustrating the internal
components of the
battery controller 703 of FIG. 7. As previously shown in FIG. 7, the battery
controller 703 is fed
signals and powered through power and communication signal paths 706a-n.
Additionally, the
battery controller 703 also provides output power and signals along power and
communication
signal paths 601a-n. The battery controller 703, according to one exemplary
embodiment of the
present invention, includes a power supply 1102, SMBus isolation switch(es)
1104, a
microcontroller 1106, an audio driver 1108, a user buttons interface 1110, a
serial
communications transceiver 1112, and a buck converter 1114.
22
CA 02750482 2011-08-25
[00138] The power supply 1102 produces various voltage levels at its output,
which are used to
power the various battery controller components shown in FIG. 11. The SMBus
isolation
switch(es) 1104 is/are used to disconnect the SMBus lines to the battery
protection printed circuit
board during charging and when the bus is used for other purposes within the
battery controller.
[00139] Microcontroller 1106 is a highly-integrated processing unit that
controls the functions
of the battery controller 703. Audio driver 1108 produces a signal that
ultimately drives the
buzzer 802 that is located in the handle assembly 302. The user buttons
interface 1110
conditions the signals received from the minimum 804 and maximum 806
activation switches
housed within the handle assembly 302. The serial communications transceiver
1112 provides
transmission and reception of differential half-duplex communications between
the battery
controller 703 and the generator 904. Finally, the buck converter 1114 steps
down the battery
voltage to produce a lower voltage for delivery to the TAG assembly 303 for
generation of the
ultrasound output signal to the transducer 902. The microcontroller controls
the output of the
buck regulator by varying or modulating the pulse widths of the input signals
to the buck
converter (i.e., pulse width modulation (PWM)). The battery controller
measures the impedance
of the switch and will not activate the system until the impedance detected
falls bellow a
predetermined threshold. This will eliminate accidental activations due to
fluid ingress which are
generally detected as higher impedances in the switch that that of a fully
closed switch. The
present line works on a similar principle, ensuring that the present line is
closed through a low
enough impedance before the battery is turned on. This is done so that
exposure of the present
pin to any conducting fluid will not accidentally turn on the battery pack.
[00140] As set forth in detail below, the battery controller 703 facilitates a
user interface, e.g., a
buzzer 802 and RGB LEDs 906, and converts the output voltage and current
output of the buck
converter, which output powers the TAG assembly 303 through at least one
voltage output path
(Vout) 601a-n.
[00141] II. HANDLE ASSEMBLY
[00142] FIG. 8 is a general block schematic diagram illustrating the handle
assembly 302 shown
in FIG. 3. The handle assembly 302 receives control and power signals over
attached power and
communication signal paths 601a-n. A second set of power and communication
signal paths
23
CA 02750482 2011-08-25
602a-n connect to the TAG assembly 303 when it is attached to the handheld
ultrasonic surgical
cautery assembly 300. As is explained in detail below, the handle assembly 302
houses the
ultrasonic waveguide assembly 304 and provides a portion of the pistol grip
that the operator
uses to grasp and operate the entire handheld ultrasonic surgical cautery
assembly 300 using, for
example, a two-stage switch of button 4608 and trigger 4606 (as introduced in
FIG. 46). The
handle assembly 302, according to one exemplary embodiment, is provided with a
speaker/buzzer 802 capable of receiving a buzzer output signal from the
battery assembly 301
through a signal path 601a-n and of producing an audible output, e.g., 65db,
suitable for
communicating specific device conditions to an operator. These conditions
include, for example,
successful coupling of assembly components, e.g., battery assembly 301 to
handle assembly 302,
high, low, or normal operation mode, fault conditions, low battery, device
overload, mechanical
failure, electrical failure, and others. The handle also includes a Min.
Button switch 804 and a
Max. Button switch 806 that, when activated, connects the respective button to
ground, which
signals the battery controller to start the ultrasonic output in either low or
high amplitude mode.
The handle assembly 302 also provides a pass-through interconnect for signals
between the
battery assembly 301 and the TAG assembly 303.
[00143] III. TAG
[00144] FIG. 9 is a block and schematic circuit diagram illustrating the TAG
assembly 303 of
FIGS. 3 and 5, which houses the transducer 902 and the generator 904. The
generator 904
converts DC power from the battery controller 703 into a higher-voltage AC
signal that drives
the transducer 902, which converts the electrical signal to mechanical motion.
[00145] a. Generator
[00146] FIG. 10 is a block circuit diagram illustrating the internal
components of the generator
904. The generator 904, according to an exemplary embodiment of the present
invention,
includes a power supply 1002, a serial communications transceiver 1004, a
microcontroller 1006,
a numerically controlled oscillator (NCO) 1008, a push/pull switching
amplifier 1010, an output
filter/matching network 1012, a motional bridge 1014, a feedback amplifier and
buffer(s) 1016,
an LED driver 1018, and indicators 906, for example, RGB LEDs. The power
supply 1002
receives power from the battery assembly 301 through lines Vbatt and GND of
the power signal
24
CA 02750482 2011-08-25
paths 602a-n and outputs various voltages that are used to power the generator
904. The serial
communications transceiver 1004 provides transmission and reception
communications between
the battery controller 703 and the generator 904, here, through a serial data
link Comm+/Comm-
of the communication signal paths 602a-n, although this communication can
occur through a
single line or through a number of lines, in series or in parallel.
[00147] The microcontroller 1006 is a highly integrated processing unit that
controls the
functions of the generator 904 and is one of two microcontrollers in the
system, the other being
part of the battery controller 703. In the exemplary embodiment, a serial data
link (Comm+,
Comm-) exists between the two microcontrollers 1006, 1106 so they can
communicate and
coordinate their operation. The microcontroller 1006 in the TAG 303 controls
generation of the
high-voltage waveform driving the piezoelectric transducer 902. The
microcontroller 1006 in the
battery assembly 301 controls conversion of the DC voltage from the battery
cells 701 to a lower
DC voltage used by the TAG 303 when generating the high voltage AC to the
transducer 902.
The battery microcontroller 1106 regulates the DC output of the battery
assembly 301 to control
the amplitude of the mechanical motion, and the TAG microcontroller 1006
controls the
frequency of the signal that drives the transducer 902. The battery
microcontroller 1106 also
handles the user interface, and the battery protection circuit 702 monitors
the battery cells 701
during system operation.
[00148] Direct digital synthesis (DDS) is a technique used to generate a
periodic waveform with
a precise output frequency that can be changed digitally using a fixed
frequency source. The
NCO 1008 is a signal source that uses the DDS technique, which can be
performed through
hardware or software. The fixed frequency input to the DDS is used to generate
a clock for the
NCO 1008. The output is a series of values that produce a time-varying
periodic waveform. A
new output value is generated during each clock cycle.
[00149] The DDS 2200, which is shown in detail in FIG. 22, works by
calculating the phase
component of the output waveform that is then converted to amplitude, with a
new phase value
being generated each clock cycle. The phase value is stored in a variable
register 2202, which
register is referred to herein as the "phase accumulator." During each clock
cycle, a fixed
number is added to the number stored in the phase accumulator to produce a new
phase value.
This fixed number is often referred to as the frequency control word or
frequency tuning word
CA 02750482 2011-08-25
because it, along with the clock frequency, determines the output frequency.
The value in the
phase accumulator spans one cycle of the periodic output waveform from 0 to
360 degrees, with
the value rolling over at 360 degrees.
[00150] The value in the phase accumulator is fed into a phase-to-amplitude
converter 2204.
For a sine wave, the amplitude can be computed using the arctangent of the
phase value. For
high speed applications, the converter usually uses a lookup table to generate
the amplitude value
from the phase value.
[00151] In a hardware implementation of DDS, the output of the amplitude
converter is input to
a digital-to-analog converter (DAC) 2206 to generate an analog output signal
fout. The analog
signal is usually filtered by a band pass or low pass filter to reduce
unwanted frequency
components in the output waveform.
[00152] As a first example, the value in the phase accumulator 2202 can be set
to an integer
from 0 to 359. If the frequency tuning word is 1, the value in the phase
accumulator 2202 will be
incremented by 1 each clock cycle. When the value reaches 359, it rolls over
to zero. If the
clock frequency is 360 Hz, the frequency of the output waveform will be 1 Hz.
The output will
therefore be a series of 360 points during each 1 second period of the output
waveform. If the
frequency tuning word is changed to 10, the value in the phase accumulator is
incremented by 10
each clock cycle, and the output frequency will be 10Hz. The output will
therefore be 36 points
for each period of the output waveform. If the frequency tuning word is 100,
the output
frequency will be 100 Hz. In that case, there will be 3.6 points for each
output period. Or, more
accurately, some cycles of the output waveform will have 3 points and some
will have 4 points.
The ratio of cycles with 4 points versus 3 points is 0.6.
[00153] As a second example, the value in the phase accumulator 2202 can be a
10 bit number.
The 10 bit number will have 1024 possible values. With a frequency tuning word
of 50 and a
clock frequency of 1 MHz, the output frequency will be 50*1 MHz/1024 = 48.828
kHz. FIG. 23
illustrates the output 2300 of the DAC 2206 and what the filtered DAC output
might look like.
[00154] If the frequency tuning word is 22, the output frequency is 22*1
MHz/1024 = 21.484
kHz. In this case, FIG. 24 illustrates the output 2400 of the DAC 2206 and
what the filtered
26
CA 02750482 2011-08-25
DAC output might look like. When power is first applied to the generator, the
state of the NCO
1008 may be undefined (or the output of the NCO 1008 may not be at a suitable
frequency). This
could lead to improper operation of the microcontroller. To ensure proper
operation of the
microcontroller, the NCO 1008 is not used to drive the clock frequency of the
microcontroller
when power is first applied. A separate oscillator is used. In one exemplary
embodiment, the
separate oscillator is integrated into the microcontroller. Using this
separate oscillator, the
microcontroller initializes the various memory locations internal to the
microcontroller and those
in the NCO 1008. Once the NCO 1008 is operating at a suitable frequency, the
microcontroller
switches the source of its clock from the separate oscillator to the NCO 1008.
[00155] If the frequency tuning word is 400, the output frequency is 400*1
MHz/1024 =
390.625 kHz. In this case, FIG. 25 illustrates the output 2500 of the DAC 2206
and what the
filtered DAC output might look like. The output sometimes has 2 points per
period and
sometimes 3 points. The waveform in FIG. 25 clearly shows the need for a
filter to obtain a clean
sine wave.
[00156] Referring back to FIG. 10, the push/pull switching amplifier 1010
converts DC power
from the battery controller 703 into a higher voltage square wave. The output
filter/matching
network is a passive filter that changes the square wave from switching
amplifier 1010 into a
smooth sinusoidal wave suitable for feeding to the transducer 902. The
motional bridge 1014 is
a circuit that produces a feedback signal in proportion to and in phase with
the mechanical
motion of the transducer 902 and waveguide assembly 304. The feedback
amplifier and buffer(s)
1016 amplifies and buffers the motional feedback signal determined within the
motional bridge
1014. As will be explained in greater detail below, the motional bridge 1014
allows the device to
run with a constant displacement/amplitude mode and varies the voltage as the
load varies. The
motional bridge is used to provide amplitude feedback and, by virtue of using
this type of
feedback, i.e., motional feedback, the system is able to run with constant
current.
[00157] In one embodiment, the TAG assembly 303 includes one or more
red/green/blue (RGB)
LEDs 906, which can be used for a variety of warning and communication
purposes. For
example green can indicate the device is functioning normally whereas red
indicates the device is
not functioning normally. It is noted that the placement of the LEDs 906 at
the generator 904 in
27
CA 02750482 2011-08-25
FIG. 9 is only for illustrative purposes. The invention envisions placing the
indicators anywhere
at the TAG assembly 303.
[00158] Through communicative interaction between the handle assembly 302 and
the TAG
assembly 303, in particular, the speaker 802 and the LEDs 906, the inventive
handheld ultrasonic
surgical cautery assembly 300 provides full feedback to an operator during use
to indicate a
plurality of conditions associated with the ultrasonic surgical cautery
assembly 300. For
instance, as mentioned above, the speaker/buzzer 802 can provide audible
warnings and audible
indicators of operational status of the ultrasonic surgical cautery assembly
300. Similarly, the
LEDs 906 can provide visual warnings and visual indicators of operational
status of the
ultrasonic surgical cautery assembly 300. As an example, the LEDs 906 can
provide an
indication of an amount of power remaining within the battery cell(s) 701 or a
lack of sufficient
power to safely carry out a surgical procedure. For instance, a first color of
the LEDs 906
indicates a fully charged battery cell(s) 701, while a second color indicates
a partially charged
battery cell(s) 701. Alternatively, various blinking patterns or constant on
states of the LEDs 906
can provide condition indicators to the user. The LED driver 1018 that is
shown in FIG. 10 is an
exemplary configuration that provides a constant current when the LEDs 906 are
illuminated.
Importantly, all of the feedback indicators to the user are uniquely present
on the handheld device
and do not require the user to be within range of a remote feedback component
that is away from
the surgical field of vision or outside of the sterile field. This eliminates
the requirement for the
physician to shift his/her attention from the surgical field to a remote
location to verify the nature
of the feedback signal.
[00159] b. Transducer
[00160] A transducer 902 is an electro-mechanical device that converts
electrical signals to
physical movement. In a broader sense, a transducer 902 is sometimes defined
as any device that
converts a signal from one form to another. An analogous transducer device is
an audio speaker,
which converts electrical voltage variations representing music or speech to
mechanical cone
vibration. The speaker cone, in turn, vibrates air molecules to create
acoustical energy. In the
present invention, a driving wave 1400 (described below) is input to the
transducer 902, which
then converts that electrical input to a physical output that imparts movement
to the waveguide
1502 (also described below). As will be shown with regard to FIG. 15, this
movement sets up a
28
CA 02750482 2011-08-25
standing wave on the waveguide 1502, resulting in motion at the end of the
waveguide 1502. For
purposes of the present invention, transducer 902 is a piezo-electric device
that converts
electrical energy into mechanical motion.
[00161] As is known, crystals in piezoelectric transducers expand when voltage
is applied. In a
transducer configuration according to the invention, as illustrated for
example in FIG. 55, the
crystals are clamped into a crystal stack 5502. A clamp bolt 5504 in this
configuration acts as a
spring if it is set to pre-compress the crystal stack 5502. As such, when the
crystal stack 5502 is
caused to expand by imparting a voltage across the stack 5502, the clamp bolt
5504 forces the
stack 5502 back to its original, pre-compressed position (i.e., it retracts).
Alternatively, the
clamp bolt 5504 can be torqued so that there is no pre-compression on the
stack 5502 and, in
such a case, the bolt will still act as a spring to pull the back mass towards
it original position.
Exemplary configurations of the transducer can be a so-called Langevin
transducer, a bolt-clamp
Langevin transducer, or a bolt-clamped sandwich-type transducer.
[00162] IV. SIGNAL PATH
[00163] FIG. 12 is a block diagram illustrating the signal path between the
battery assembly 301
and the TAG assembly 303. First, a DC-DC step-down converter 1202 steps the
voltage from
the battery cells 701 down from a first voltage to a second, lower voltage.
The DC-DC step-
down converter 1202 includes the multi- or variable-phase (depending on amount
of power
needed) buck converter 1114 and the battery microcontroller 1106, which are
both shown in FIG.
11 within the battery assembly 301. The battery microcontroller 1106 controls
the buck
converter 1114 to regulate the DC voltage fed to the TAG assembly 303.
Together, the buck
converter 1114 and the microcontroller 1106 perform the DC to DC conversion
function in the
battery assembly 301. In an exemplary embodiment of the invention, a two-phase
buck converter
1114 is used. Another exemplary embodiment can utilize a buck converter having
additional
phases. In such a case, phase shedding can be employed. The number of phases
used can change
dynamically to keep the converter operating at optimal efficiency, which is a
consideration for a
battery powered device. In other words, when less output power is required,
the power losses
internal to the converter can be reduced by reducing the number of active
phases.
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CA 02750482 2011-08-25
[00164] The DC output voltage from the battery assembly 301 powers the
push/pull switching
amplifier 1010 in the TAG assembly 303, which assembly 303 converts the DC
signal to a higher
voltage AC signal. The TAG microcontroller 1006 controls the amplifier 1010.
The output
voltage of the push pull switching amplifier 1010 is, in general, a square
wave, an example of
which is shown in FIG. 13, which waveform 1300 is undesirable because it is
injurious to certain
components, in particular, to the transducer 902. Specifically, the abrupt
rising and falling edges
of a square wave cause corresponding abrupt starts and stops of the ultrasonic
waveguide to
produce a damaging "rattling" affect on the waveguide. The square wave 1300
also generates
interference between components. For example, higher additional harmonic
frequencies of a
square wave can create unwanted electrical interference and undesired
operation of the circuit(s).
This is in contrast to a pure sine wave, which only has one frequency.
[00165] To eliminate the square wave, a wave shaping or matching circuit 1012
(sometimes
referred to as a "tank circuit") is introduced. The tank circuit 1012 includes
such components as,
for example, an inductor, along with a capacitor in conjunction with the
transducer capacitance,
and filters the square wave into a smooth sine wave, which is used to drive
the transducer 902 in
a way that produces non-damaging ultrasonic motion at the waveguide. An
exemplary sine wave
1400 suitable for driving the transducer 902 is shown in FIG. 14. The matching
circuit 1012, in
one exemplary embodiment of the present invention, is a series L-C circuit and
is controlled by
the well-known principles of Kirchhoff s circuit laws. However, any matching
circuit can be
used to produce a smooth sine wave 1400 suitable for driving the transducer
902. In addition,
other driving signals can be output from the matching circuit 1012 that are
not smooth sine
waves but are useful for driving the transducer 902 in a way that is less
injurious than a square
wave.
[00166] In practice, the matching network 1012 is tuned to match a particular
transducer to
which it feeds. Therefore, transducers and matching networks are best matched
if they remain as
a pair and are not placed in combination with other device. In addition, if
each transducer 902
had its own matching network, the smart battery 301 could feed different
frequencies to the
different transducers, the frequencies being respectively matched to a
particular blade in a
waveguide assembly 304. Two popular frequencies for ultrasonic surgery devices
are 55kHz and
40kHz.
CA 02750482 2011-08-25
[00167] V. RESONANCE
[00168] FIG. 15 is a diagrammatic illustration of the affect that a resonant
sine wave input to the
transducer 902 has on the waveguide 1502 of the ultrasonic cutting device. In
accordance with
an exemplary embodiment of the present invention, the sinusoidal pattern shown
by the dotted
lines in FIG. 15 represents the amplitude of axial motion along the length of
the waveguide 1502,
which is coupled to the transducer 902. Responding to a rising portion 1402 of
the driving sine
wave 1400 (shown in FIG. 14), the stack expands in a first direction 1508.
During the negative
portion 1404 of the driving wave 1400 (shown in FIG. 14), the pre-compression
or the induced
compression of the stack returns the stack to its steady-state, i.e., the
portion 1504 of the
transducer 902 is moved in a second direction 1512. As stated above, a smooth
sine wave 1400,
in contrast to the square wave 1300, allows the transducer 902 and waveguide
1502 to slow
before changing directions. The smoother movement is less injurious to the
device's
components.
[00169] The alternating movement 1508, 1512 of the transducer portion 1504
places a
sinusoidal wave 1514 along the length of the waveguide 1502. The wave 1514
alternatively pulls
the distal end 1520 of the waveguide 1502 toward the transducer 902 and pushes
it away from
the transducer 902, thereby longitudinally moving distal end 1520 of the
waveguide 1502 along
distance 1518. The tip of the waveguide 1502 is considered an "anti-node," as
it is a moving
point of the sine wave 1514. The resulting movement of the waveguide 1502
produces a
"sawing" movement along distance 1518 at the distal end 1520 of the waveguide
1502. (The
wave 1514 and linear movement along distance 1518 are greatly exaggerated in
FIG. 15 for ease
of discussion.) This high-speed movement along distance 1518, as is known in
the art, provides
a cutting instrument that is able to easily slice through many materials, in
particular, tissue and
bone. The rapidly moving distal end 1520 of the waveguide 1502 also generates
a great deal of
frictional heat when so stimulated, which heat is absorbed by the tissue that
the waveguide 1502
is cutting. This heat is sufficient to cause rapid cauterization of the blood
vessels within the
tissue being cut.
[00170] If the driving wave 1514 traveling along the waveguide 1502 is not a
resonant wave,
there will be no standing wave, which means that are no nodes or antinodes.
This means that
there is very little motion. There also exists the possibility of operating
the device at an incorrect
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CA 02750482 2011-08-25
resonant frequency. Operating at the wrong resonance can produce, for example,
undesirable
motion such as "slapping." In such a case, the distal end 1520 of the
waveguide 1502 moves
transverse to the longitudinal axis of the waveguide 1502. Any incorrect mode
is not ideal and is
unreliable for providing adequate cutting and surgical cautery. The invention,
however, as is
explained below, utilizes a phase locked loop (PLL) in the generator 904 to
ensure that the
movement 1508, 1512 of the waveguide 1502 remains resonant along the waveguide
1502 by
monitoring the phase between the motional current and motional voltage
waveforms fed to the
transducer 902 and sending a correction signal back to the generator 904. The
TAG
microcontroller 1006 controls the frequency and ensures it is in the proper
range so as not to
excite an undesired resonant frequency. As an added feature, the present
invention can be
provided with piezo-electric crystal stacks 1504 that are cut in varying
planes, thereby creating a
torsional, or twisting motion of the blade rather than only a sawing motion.
The present
invention can easily be adapted to a full set of uses using requiring a
drilling-type motion instead
of or with the sawing motion just described.
[00171] As just explained, ideally, the transducer 902 and waveguide 1502 are
driven at their
resonant frequency. Resonance is achieved when current and voltage are
substantially in phase at
the input of the transducer 902. For this reason, the generator 904 uses the
PLL and the signals
derived from the current and voltage input to the transducer 902 to
synchronize the current and
voltage with one another. However, instead of simply matching the phase of the
input current to
the phase of the input voltage, the present invention matches the current
phase with a phase of
the "motional" voltage and/or matches the input voltage phase with a phase of
the "motional"
current. To accomplish this, a motional bridge circuit is used to measure the
mechanical motion
of the transducer and waveguide and to provide feedback as to the operation of
the transducer
and waveguide. The motional feedback signal from the bridge is proportional to
and in phase
with the motion of the transducer 902 and waveguide 1502.
[00172] VI. MOTIONAL CONTROL
[00173] a. Transducer Circuit Model
[00174] FIG. 16 is a schematic circuit diagram of a model transducer 1600,
such as transducer
902, which contains piezo-electric material. Piezo-electric transducers are
well known in the art.
32
CA 02750482 2011-08-25
The mass and stiffness of the piezo-electric material creates a mechanically
resonant structure
within the transducer. Due to the piezo-electric effect, these mechanical
properties manifest
themselves as electrically equivalent properties. In other words, the
electrical resonant frequency
seen at the electrical terminals is equal to the mechanical resonant
frequency. As shown in FIG.
16, the mechanical mass, stiffness, and damping of the transducer 902 may be
represented by a
series configuration of an inductor/coil L, a capacitor C2, and a resistor R,
all in parallel with
another capacitor C1. The electrical equivalent transducer model 1700 is quite
similar to the
well-known model for a crystal.
[00175] Flowing into an input 1610 of the electrical equivalent transducer
model 1600 is a
transducer current iT. A portion ic of i flows across the parallel capacitor
C1, which is of a type
and value that, for the majority of the expected frequency range, retains a
substantially static
capacitive value. The remainder of iT, which is defined as im, is simply iT ¨
ic and is the actual
working current. This remainder current 44 is referred to herein as the
"motional" current. That
is, the motional current is that current actually performing the work to move
the waveguide 1502.
[00176] Known prior-art designs regulate and synchronize with the total
current iT, which
includes ic and is not an indicator of the amount of current actually causing
the motion of the
waveguide 1502 of the transducer 902. For instance, when the blade of a prior-
art device moves
from soft tissue to denser material, such as other tissue or bone, the
resistance R increases
greatly. This increase in resistance R causes less current im to flow through
the series
configuration R-L-C2, and more current ic to flow across capacitive element
C1. In such a case,
the waveguide 1502 slows down, degrading its performance. It may be understood
by those
skilled in the art that regulating the overall current is not an effective way
to maintain a constant
waveguide displacement. As such, one novel embodiment of the present
invention
advantageously monitors and regulates the motional current 44 flowing through
the transducer
902. By regulating the motional current 44, the movement distance of the
waveguide 1502 can
be regulated easily.
[00177] b. Series Circuit Model
[00178] FIG. 17 is a schematic circuit diagram of an inventive circuit 1700
useful for
understanding how to obtain the motional current 44 of the transducer 902. The
circuit 1700 has
33
CA 02750482 2011-08-25
all of the circuit elements of the transducer model 1600 plus an additional
bridging capacitive
element CB in parallel with the transducer model 1600 of FIG. 16. However, the
value of CB is
selected so that Cl/CB is equal to a given ratio r. For efficiency, the chosen
value for CB should
be relatively low. This limits the current that is diverted from im. A
variable power source VT is
applied across the terminals 1702 and 1704 of the circuit 1700, creating a
current iB through the
capacitive element CB, a current iT flowing into the model transducer 1600, a
current ic flowing
through capacitor C1, and, finally, the motional current im. It then follows
that im = iT ¨ r = iB.
This is because:
aVr C1 Fir Ft1)"
B B = - = ___ and ic= CI __
a, r a,
Therefore, ic = r = iB and, substituting for ic in the equation im = iT ¨ ic,
leads to: im = iT ¨ r = 113.
[00179] Now, by knowing only the total current and measuring the current
through the bridge
capacitor iB, variations of the transducer's motional current im can be
identified and regulated.
The driver circuit, represented by block 2708 and the transformer 2710 in FIG.
27, is included in
the push-pull switching amplifier 1010 of FIG. 10. The driver circuit, then,
acts as a current
controller and regulates the motional current im by varying an output of the
driver circuit based
on the product of the current flowing through the bridge capacitance CB
multiplied by the ratio r
subtracted from a total current IT flowing into the transducer 902. This
regulation maintains a
substantially constant rate of movement of the cutting blade portion of the
waveguide 1502
across a variety of cutting loads ¨ something that has not been possible to
date. In one exemplary
embodiment, sensing circuits 1014 measure the motional voltage and/or motional
current.
Current and voltage measuring devices and circuit configurations for creating
voltage meters and
current meters are known in the art. Values of current and voltage can be
determined by the
present invention in any way now known or later developed, without limitation.
[00180] Regulation of the motional current im is a true way to maintain the
integrity of the
instrument and ensure that it will operate at its peak performance under
substantially all
conditions expected in an operating environment. In addition, such regulation
provides these
advantages within a package small enough and light enough to be easily held in
one hand ¨ a
configuration that has never occurred in the field.
34
CA 02750482 2011-08-25
[00181] c. Transducer Circuit Model
[00182] FIG. 18 shows another embodiment of the present invention, where the
transducer 902
is schematically represented as a parallel configuration of a resistive
element R, an inductive
element L, and a capacitive element C4. An additional capacitive element C3 is
in a series
configuration between an input 1702 and the parallel configuration of the
resistive element R, the
inductive element L, and the capacitive element C4. This parallel
representation models the
action of the transducer in a so-called "antiresonant" mode of operation,
which occurs at a
slightly different frequency. A transducer voltage VT is applied between the
input terminals
1702, 1704 of the transducer 902. The transducer voltage VT is split between a
voltage Vc across
capacitive element C3 and a motional voltage Vm across the parallel
configuration of the resistive
element R, the inductive element L, and the capacitive element C4. It is the
motional voltage Vm
that performs the work and causes the waveguide 1502 to move. Therefore, in
this exemplary
embodiment, it is the motional voltage that is to be carefully regulated.
[00183] d. Parallel Circuit Model
[00184] FIG. 19 shows an exemplary embodiment of an inventive circuit
configuration 1900,
according to the present invention including the transducer model 1800 of FIG.
18. The circuit
configuration 1900 adds to the transducer model 1800 three additional
capacitive elements C5,
C6, and C7. Capacitive element C5 is in series with the transducer model
circuit 1800 of FIG. 18
while the capacitive elements C6 and C7 are in series with one another and,
together, are in
parallel with the series combination of the capacitive element C5 and the
transducer circuit model
1800.
[00185] This circuit is analogous to a Wheatstone bridge measuring instrument.
Wheatstone
bridge circuits are used to measure an unknown electrical resistance by
balancing two legs of a
bridge circuit, one leg of which includes the unknown component. In the
exemplary circuit
configuration shown in FIG. 10, a motional voltage Vm, which equals VT ¨ VC,
is the unknown.
By determining and regulating the motional voltage Vm, the inventive
configuration allows a
consistent waveguide movement to be maintained as set forth below.
CA 02750482 2011-08-25
[00186] Advantageously, the capacitive element C7 is selected so that its
value is a ratio A of
capacitive element C3, with A being less than one. Likewise, the capacitive
element C6 is
selected so that its value is the same ratio A of the capacitive element C5.
The ratio of C5/C3 is
also the ratio A.
[00187] Because the ratio of C3/C7 is A and the ratio of C5/C6 is also A, the
bridge is balanced.
It then follows that the feedback voltage Vfb divided by the motional voltage
Vm is also the ratio
A. Therefore, V,, can be represented as simply A = V.
[00188] If the voltage across the model transducer 1800 is still VT, an input
voltage V,õ equals
VT plus the voltage VB across the capacitive element C5. The feedback voltage
VFB is measured
from a first point located between capacitive elements C6 and C7 and a second
point located
between the transducer and the capacitive element C5. Now, the upstream
components of the
TAG assembly 303 act as a voltage controller and vary the power Vil, to
maintain a constant
feedback voltage Vit), resulting in a substantially constant motional voltage
and maintaining a
substantially constant rate of movement of the cutting blade portion of the
waveguide 1502
across a variety of cutting loads. Again, unlike the prior art, the present
invention is not simply
regulating the input voltage V,n, it is varying the input voltage V,n for the
purpose of regulating
the motional voltage Vm -- which is novel in the art.
[00189] e. Transformer Series Monitoring
[00190] FIG. 20 shows another exemplary embodiment of the present invention
where the
transducer 902 is of the circuit configuration shown in FIG. 16. The
configuration of FIG. 20
works similarly to that shown in FIG. 17 and as described above in connection
with FIG. 17.
However, in this circuit configuration 2000, a pair of transformers 2004 and
2008 is used to
determine and monitor the motional current Im. In this exemplary embodiment, a
primary
winding 2002 of the first transformer 2004 is in a series configuration with a
bridge capacitor CB.
Similarly, a primary winding 2006 of the second transformer 2008 is in a
series configuration
with the model transducer 1600. The leads 2010, 2012 of the secondary winding
2014 of the first
transformer 2004 are coupled through a resistor R2. The leads 2016, 2018 of
the secondary
winding 2020 of the second transformer 2008 are coupled through a resistor R1.
In addition, the
36
CA 02750482 2011-08-25
first lead 2010 of the secondary winding 2014 of the first transformer 2004 is
directly connected
to the first lead 2016 of the secondary winding 2020 of the second transformer
2008.
[00191] Current iB passing through the primary winding 2002 of the first
transformer 2004
induces a current in the secondary winding 2014 of the first transformer 2004.
Similarly, the
currents including ic passing through the capacitive element C1 of the
transducer 1600 and the
motional current im of the transducer 1600 combine and go through the primary
winding 2006 of
the second transformer 2008 to find ground 2022. The current in the primary
winding 2006
induces a current on the secondary winding 2020. As noted by the dots ("=") on
the transformers
2004, 2008, the secondary windings 2014, 2020 are in opposite directions from
one another, with
reference to the primary windings 2002, 2006, respectively, and induce a
voltage Vth across
resistors R1 and R2. By selecting values for R1 and R2 so that a ratio of
RI/R2 is equal to the ratio
of the values CB/Cl, the feedback voltage Vth will always be proportional to
the motional current
im. Now, the upstream components of the generator 904 act as a voltage
controller and vary the
input power (V,,, and Li) to maintain a constant feedback voltage Vth,
resulting in a substantially
constant motional current im and maintaining a substantially constant rate of
movement of the
cutting blade portion of the waveguide 1502 across a variety of cutting loads.
Again, unlike the
prior art, the present invention is not simply regulating the input voltage
vin, it is varying the
input current I,n for the purpose of regulating the motional current im --
which is novel in the art.
[00192] f. Transformer Parallel Monitoring
[00193] FIG. 21 shows another exemplary embodiment of the present invention
where the
model transducer 1800 is modeled by the circuit configuration shown in FIG.
18. The
configuration of FIG. 21 works similarly to that shown in FIG. 19 and as
described above in
connection with FIG. 19. However, in this circuit configuration 2100, a
transformer 2110 is used
to determine and monitor the motional voltage Vm of the transducer 1800. In
this embodiment, a
primary winding 2106 of the transformer 2110 is in a series circuit
configuration with an
inductive element L2 and a capacitive element C1. A voltage V,õ is applied
across input leads
2102, 2104 of the circuit formed by the primary winding 2106 of the
transformer 2110, the
inductive element L2, and the capacitive element C1. A current through the
primary winding
2106 induces a corresponding current in the secondary winding 2108 of the
transformer 2110.
The secondary winding 2108 of the transformer 2110 is in a parallel
configuration with a
37
CA 02750482 2011-08-25
combination of the transducer 1800 and a bridge capacitor CB. The two
components forming the
combination are in a series configuration.
[00194] In this embodiment, the secondary winding 2108 is tapped at a point
2112. By tapping
the secondary winding 2108 at a point where a first portion of the secondary
winding 2108 has m
turns and a second portion of the secondary winding 2108 has n turns (where n
is less than m), a
selectable percentage of the induced voltage on the secondary winding 2108
appears from point
2112 to ground 2114.
[00195] Again, this circuit is analogous to a Wheatstone bridge measuring
instrument. One leg
is the first secondary winding m, the second leg is the second secondary
winding n, the third leg
is the transducer model 1800, and the fourth leg is the capacitor CB. In the
instant circuit
configuration shown in FIG. 21, the voltage Vm is the unknown. By determining
and regulating
the motional voltage Vm, a consistent waveguide movement is maintained.
[00196] By selecting a value of the bridge capacitor CB to be less than the
transducer
capacitance C3 by the same percentage that the number of turns n is less than
the number of turns
m (i.e., min = C3/CB), the value of a feedback voltage Vth will reflect the
motional voltage Vm.
The invention can determine whether the motional voltage Vm is changing by
monitoring the
feedback voltage Vfb for changes.
[00197] By using the equivalent-circuit transducer model 1800, which models a
parallel-
resonant (or "anti-resonant") transducer, the transducer may be driven in the
parallel resonant
mode of operation, where motion is proportional to voltage. The advantage of
this mode of
operation is that the required constant-voltage-mode power supply is simpler
to design and safer
to operate than a constant-current-mode power supply. Also, because the
transducer has a higher
impedance when unloaded (rather than a lower impedance when unloaded in the
series-resonant
mode of operation), it naturally tends to draw less power when unloaded. The
parallel-resonant
mode of operation, however, is more difficult to maintain because the resonant
bandwidth is
narrower than that of the series-resonant mode and has a slightly different
natural resonant
frequency; hence, the mechanical components of the device must be specifically
configured to
operate at either the series resonant or parallel-resonant mode of operation.
38
CA 02750482 2011-08-25
[00198] The present invention controls the voltage and varies the power V,n to
maintain a
constant feedback voltage Vfb, resulting in a substantially constant motional
voltage Vm and
maintains a substantially constant rate of movement of the cutting blade
portion of the waveguide
1502 across a variety of cutting loads. Again, unlike the prior art, the
present invention is not
simply regulating the input voltage Vin, it is varying the input voltage
for the purpose of
regulating the motional voltage Vm -- which is novel in the art.
[00199] In accordance with the present invention, the microcontroller 1006 in
the TAG 303
monitors the feedback signal through motional bridge 1014 to generate the
signal that goes to the
primary side of transformer 1010. The TAG microcontroller 1006 calculates (in
the CLA 912)
the phase difference between these signals and adjusts the NCO 1008 output to
make the phase
difference equal to zero. When the motional feedback signal is in phase with
the output of the
push-pull switching amplifier 1010, the system is operating at series
resonance. The phase and
magnitude of the motional feedback signal is computed using a discrete Fourier
transform (DFT).
In one exemplary embodiment of the present invention, the phase reference for
the DFT
computation is the drive signal for the push-pull amplifier 1010. The
frequency can be changed
to cause the push-pull drive signal to be in phase with the motional feedback
signal.
[00200] According to one exemplary embodiment of the present invention, if the
phase of the
motional feedback signal is positive, it is an indication the running
frequency is below the
resonant frequency and the running frequency should be increased; if the phase
is negative, it is
an indication the running frequency is above the resonant frequency and the
running frequency
should be decreased; if the phase is close to zero, the running frequency is
close to the resonant
frequency of the transducer 902 and waveguide 1502. In the generator 904, the
NCO 1008
(utilizing DDS) is used to alter the frequency appropriately.
[00201] Significantly, the NCO 1008 outputs a clock to the CPU's external
clock input at a
frequency, for example, 6 times less that the operating frequency of the TAG
microcontroller
1006. The external frequency input is fed into the processor's Phase Lock Loop
(PLL) and
multiplied by a factor of 6 to obtain the CPU's SYSCLK. The NCO 1008 is
controlled by the
processor through an SPI interface. The SPI interface is used to write a 32-
bit divisor to the
NCO 1008 that is used to divide the 25-MHz fixed frequency clock to obtain the
desired output
frequency. By controlling the DDS 2200, the TAG provides synchronized
operation of hardware
39
CA 02750482 2011-08-25
with the oscillation frequency. In other words, to the main processor 914, it
appears as though
the frequency is constant, thereby simplifying the sampling and calculation of
the motion
feedback phase.
[00202] VII. STARTUP OPERATION
[00203] Startup conditions are different than those during steady state
operation, which is
described in detail in the following section. At startup, the waveguide 1502
is initially at rest
and, therefore, there is no waveguide motion. Accordingly, there is no
immediate, ascertainable
motional feedback signal that can be used to determine the composite resonant
frequency of the
transducer 902 and waveguide 1502. As a result, the inventive system has an
ability to operate in
a different mode during an initial startup period than during steady state.
[00204] A startup procedure according to an exemplary embodiment of the
present invention is
represented in the process flow diagram of FIG. 72, which illustrates an
interchange between the
battery controller 703 and the generator 904 of the TAG assembly 303. In this
particular
embodiment, as described in detail below, the relationship between the battery
controller and
generator can be described as a "master-and-slave" relationship, as the
battery controller issues
all commands to the generator 904 and the generator 904 receives all of its
instructions from the
battery controller 703. Alternatively, the generator 904 of the TAG assembly
303 could act as
the "master" and issue all commands to the battery controller 703, or, the
generator 904 of the
TAG assembly 303 and the battery controller 703 may function as peers.
[00205] Prior to activation, both the battery controller 703 and the generator
904 are idle at steps
7201 and 7202, respectively. In step 7203, the battery controller 703 is
awakened out of its idle
condition, for example, by the user squeezing the button/trigger 4608. To
begin the exchange
between the battery controller 703 and the generator 904, the battery
controller 703 relays a
signal, such as an "ULTRASOUND ON" command 7205, to the generator 904 using
the
communication lines 602a-n (i.e., Comm+/Comm-). If operating properly, the
generator
acknowledges the command 7205 received from the battery controller 703 and, in
return, signals
a positive response 7204, such as an "ULTRASOUND ON" response, to the battery
controller
703 using the communication lines 602a-n (i.e., Comm+/Comm-). However, if the
generator 904
does not positively respond to the initial command 7205 from the battery
controller 703 before a
CA 02750482 2011-08-25
specific period of time has lapsed (e.g., 10 ms), the battery controller
issues a fault condition at
step 7207, such as a "FAILURE TO START" condition, and terminates the
operation cycle at
step 7209. At such time, appropriate indicators can be actuated.
[00206] a. Current and Amplitude Control
[00207] If there is a successful acknowledgment by the generator 904 of the
"ULTRASOUND
ON" command 7205 sent from the battery controller 703, the microcontroller
1106 in the battery
controller 703 initiates a process for quickly and safely advancing the
current rate in the TAG
assembly 303 and resulting in a resonant motion output from the TAG assembly
303 to the
waveguide 1502. Advancement proceeds from an idle condition to a level
predicted to be within
a "ballpark window" for producing an ascertainable motional feedback signal
and achieving a
beginning resonant frequency condition. As shown in FIG. 11, the
microcontroller 1106 in the
battery controller 703 has two processing units. A first processing unit, the
Control Law
Accelerator ("CLA") 1116, handles a first, inner, current-control loop 2601
(see FIG. 26), and the
second processing unit, a main processor 1118, handles a second, outer,
amplitude-control loop
2602 (see FIG. 26). At the outset, in step 7213, microcontroller 1106 turns on
the buck power
supply 1114 and initializes the CLA 1116. The CLA 1116 uses a
proportional¨integral¨
derivative ("PID") control algorithm to compute a new duty cycle value for the
Pulse Width
Modulators ("PWMs") that are driving the two-phase buck converter 1114. At
step 7215, the
battery controller 703 starts the PWMs and begins, at step 7211, using a fast,
non-linear PID
control loop, to increase the output voltage of the DC-DC converter 1202. The
increasing output
voltage causes a corresponding increase in the input current to the push/pull
amplifier 1010 of the
generator 904. At step 7217, the output voltage increases, or is otherwise
modified, until, at step
7219, the actual, measured input current reaches a predetermined reference
current level, referred
to herein as "ref." 'ref is a calibrated value that is predicted to create a
driving wave output from
the transducer 902 that will achieve a displacement of the waveguide 1502 and
place the
resulting amplitude near a value sufficient to reach the target resonant
frequency. 'ref is initially
set by the battery microcontroller 703 in step 7225. This calibrated value for
Ira may be stored
inside the TAG assembly 303 and read by the battery microcontroller 703 upon
establishment of
the communication link 7204.
41
CA 02750482 2011-08-25
[00208] Table 1 below illustrates an example of a non-linear PID control loop
or algorithm in
accordance with the present invention, whereby the output voltage level is
modified until the
actual, measured input current reaches the reference current, 'ref. In this
example, the non-linear
PID control loop divides the percent error of the actual, measured input
current versus the
reference current 'ref into 5% bins, which are shown below as constants Go
through Gn (whereby
"n" is some number of the last step prior to reaching Tref). Each bin has its
own non-linear tuning
coefficients (e.g., Kp, Kb and Kd). The non-linear tuning coefficients allow
for the output voltage
and, in turn, the actual input current, to initially advance quickly towards
the reference current
point 'ref when the input current is far away from the reference current
point, and then slowly
reach the reference current point 'ref once the input current value is close
to reaching the reference
current point. As a result, the system is less prone to being disturbed by
noise. In this particular
example, the non-linear PID within the CLA 1116 shapes the overshoot to no
more than 15%
greater than 'ref. It is desirable to have the control loop maintain current
but not to allow over
current for any significant time; in other words, the loop must make the
current retract from an
overcurrent state quickly. Accordingly, the non-linear PID loop of the CLA
1116 shapes the
increase of the output voltage and input current in such a way that the input
current advances
quickly and accurately to the desired reference current level 'ref, but does
so in such a way that is
stable and avoids a dangerous "overcurrent" condition.
TABLE 1
Gain constant: Go G1 G2 Gõ Gn G1 Go
Percent away 50% 45% 40% ....5% 'ref -5% -10% -15%
from Tref:
[00209] In the meantime, while the input current is steadily increasing under
the control of the
battery microcontroller 1106, the initial signal, i.e., the "ULTRASOUND ON"
command 7205
from the battery controller 703, received by the generator, causes the TAG
microcontroller 1006
to begin its own initialization process in parallel with the operation of the
battery controller 703.
As set forth above with regard to FIG. 9, the microcontroller 1006 in the TAG
assembly 303 has
two independent processing units: the CLA 912 and the main processor 914.
Referring back to
FIG. 72, at steps 7200 and 7206, upon receiving the initial command 7205 from
the battery
42
CA 02750482 2011-08-25
controller 703, the TAG microcontroller 1006 initializes the CLA 912 and
starts the ultrasound
PWMs that drive the ultrasonic frequency at a frequency within the operating
frequency range of
the waveguide and transducer. At this initial start up stage, any motional
feedback signal that is
present is weak and, therefore, it is desirable to use a high gain amplifier
to provide a higher
signal level because the signal level is initially very small. At step 7208,
as the input current
from the battery assembly is increasing, the amplitude (i.e., the displacement
of the mechanical
motion) is incrementing proportionally until it reaches a set point or level
within 20% of a "target
amplitude," which should produce a motional feedback signal and place the TAG
assembly 303
in a "ballpark window" for achieving the resonant frequency. The "target
amplitude" is a pre-
determined, safe, threshold level. It is undesirable to surpass this threshold
level and, when
surpassed (e.g., by 10-12%), indicates an "over-amplitude" condition that is
undesirable and
causes the device to initiate a fault condition and control shutdown.
[00210] To regulate the amplitude level of the TAG assembly 303, the battery
controller 703
closely monitors the amplitude level. The battery controller 703 issues a
command 7221 at
frequent intervals (e.g., every 4 ms), such as an "AMPLITUDE REQ" command, to
the TAG
assembly 303 using at least one of the communication lines 602a-n (e.g.,
Comm+/Comm-). In
response, the battery controller 703 receives a signal 7210, through at least
one of the
communication lines 602a-n (e.g., Comm+/Comm-), such as an "AMPLITUDE REQ"
response,
from the TAG assembly 303, which provides the battery controller 703 with a
measurement of
the amplitude level of the TAG assembly 303. At each interval that a
measurement of the
amplitude level is determined by the battery controller 703, the battery
microcontroller 1106, at
step 7223, makes one of several possible determinations based upon the
amplitude measurement.
If the amplitude level has reached the level of within 20% of the "target
amplitude," or,
effectively, 80% of the "target amplitude," in step 7227, the power control is
switched from the
inner, current-control loop 2601 to the outer, amplitude-control loop 2602,
which is described in
further detail below. If the amplitude level has not yet reached 80% of the
"target amplitude," in
step 7229, the current control loop will maintain the current at the reference
current level 'ref until
the amplitude reaches the 80% point.
[00211] However, if the amplitude level still has not reached the 80% point
within a set period
of time (e.g., 250 ms), this indicates a "low amplitude" fault condition 7231
that may be due to,
43
CA 02750482 2011-08-25
for example, a stalled blade of the waveguide 1502. In response, the battery
microcontroller
1106 terminates the operation cycle at step 7209 and issues, for example, an
"ULTRASOUND
OFF" command 7233, to the generator 904. In return, the generator 904 relays a
response 7212,
such as an "ULTRASOUND OFF" response, indicating that it has ceased active
operation. If the
potentially dangerous condition occurs in which the amplitude level has
actually surpassed the
level of within 20% of the "target amplitude," the battery microcontroller
1106 immediately
issues a fault condition 7235 and terminates the operation cycle at step 7209,
as described above,
due to this "over-amplitude" condition.
[00212] b. Frequency Lock
[00213] Now, referring to FIG. 72A, as previously mentioned, upon
initialization, the TAG
microcontroller 1006 controls the frequency of the signal that drives the
transducer 902 based
upon its detection of the motional feedback signal. At the beginning of the
startup process, in
step 7206, the operating frequency is set at a fixed value that is within the
operating frequency
range of the transducer 902 and waveguide 1502 (e.g., 55.2 kHz). If present at
that set frequency,
a motional feedback signal from the bridge circuit is routed to a high and low
gain buffer. Each
of these signals is fed into the analog-to-digital converter ("ADC") 908 of
the microcontroller
1006 in the TAG assembly 303. Initially, the high-gain, buffered-feedback
signal is selected as
the motional feedback signal will initially be small. A main function of the
CLA 912 is to take
the output from the ADC, perform the Discrete Fourier Transform ("DFT")
calculations, and
pass the results to the main processor 914. Shown as step 7218, the results
from the DFT
calculations are the phase and magnitude of the motional feedback ("MF")
signal, as well as the
real and imaginary terms for the signal.
[00214] A tuning loop is called once per ultrasound cycle. If, at step 7214,
it is determined that
a valid motional feedback signal does not exist at the set frequency, the
system simply waits until
there is a valid motional feedback signal. However, if a fixed period of time
has been exceeded
as determined by a cycle timeout timer, and there is still no valid motional
feedback signal, a
cycle activation limit "timeout" is triggered at step 7216 and the generator
904 turns off
[00215] Initially, at step 7222, the system employs a high-gain-buffered A-to-
D channel such
that the high-gain-buffered feedback signal is selected. This allows the
system to lock at a lower
44
CA 02750482 2011-08-25
motional feedback signal level. A determination of whether or not the motional
feedback signal
has reached a defined "THRESHOLD" value is made at step 7220. If the motional
feedback
signal has reached the defined "THRESHOLD" value, the amplitude of the
motional feedback
signal has increased to the point that a valid motional feedback signal has
emerged from any
obstructive noise such that the DFT calculations in the CLA 912 are reliable.
At this point, in
step 7224, the system switches to the low-gain channel. However, should the
system fall below
this "THRESHOLD" value, the A-to-D channel can switch back to the high-gain
channel as
shown in step 7226. By having the ability to switch to the low-gain channel at
this point, a
higher resolution A/D converter is beneficially not required.
[00216] At step 7228, if the motional feedback signal is above a starting
threshold value, the
generator 904 enters a frequency-tuning mode for locking the set frequency
onto the resonant
frequency of the TAG assembly 303 in parallel with the current and amplitude
controls described
above. In accordance with an exemplary embodiment of the present invention,
the process for
achieving resonant frequency is not a process of sweeping for the optimum
frequency, but rather
is uniquely a tracking or tuning process for locking onto the optimum
frequency. However, the
present invention may also employ a frequency sweeping mode whereby the
initial operating or
set frequency is chosen to be at a lower boundary of the "ballpark window" of
the predicted
resonant frequency and is steadily incremented until it reaches the resonant
frequency or vice
versa.
[00217] Once frequency tuning mode is entered, the main processor 914 of the
TAG
microcontroller 1006 uses the results of the DFT calculation (i.e., the phase
and magnitude of the
motional feedback signal) to control the running frequency of the generator.
The tuning
algorithm is divided into two states: STARTING and LOCKING. In the STARTING
phase at
step 7230, a determination is made of whether or not the motional feedback
signal has reached a
defined "STARTUP THRESHOLD" value. If the motional feedback signal has reached
the
defined "STARTUP THRESHOLD" value, the amplitude of the motional feedback
signal has
increased to the point that the system can actively begin moving towards
resonance at step 7232.
If the determination at step 7230 is that the motional feedback signal has not
reached the defined
"STARTUP THRESHOLD" value, the process moves to step 7234. At step 7234, the
CA 02750482 2011-08-25
STARTING phase simply waits until the point is reached whereby there is a
large enough
motional feedback signal to allow locking.
[00218] In the LOCKING phase 7236, the sine of the phase offset between the
motional
feedback signal and the driving signal is used along with the differential of
the sine to determine
the size and direction of the frequency step to adjust the output frequency to
move the system to
resonance. Although the phase is naturally a tangent function, the sine of the
phase is used to
determine the frequency step because it is bounded by the value 1 and closely
approximates the
phase value at small angles, whereas a tangent function has the undesirable,
unbounded range of
00.
[00219] In step 7238, a PID loop is used to calculate the frequency step in
either a plus or minus
direction. The PID loop is non-linear, whereby the value of the sine is used
to determine a bin
number. That bin number is used as an index to access the tuning coefficients
used by the PID.
An index table contains the proportional gain, the integral gain, and the
differential gain. In
addition, the entry sine value to enter a bin differs from the value to exit a
bin. This introduces
hysteresis to prevent oscillations near the bin transitions.
[00220] As previously explained, a non-linear PID is used to achieve a rapid
frequency lock.
Table 2 below illustrates an example of a non-linear, asymmetric PID loop or
algorithm in
accordance with the present invention whereby the size in frequency step is
staggered until it
reaches the target resonance frequency, fies. In this example, the gain
constants PID0 through
PID n (whereby "n" is some number of the last frequency step prior to reaching
fes) are separated
by non-linear increments. The gain values have been chosen to move the system
toward
resonance quickly when the system is far from resonance and slowly when the
system is close to
or at resonance. It is important to step slowly when close to or at resonance
in order to avoid
inducing frequency modulation, which would cause undesirable effects on the
amplitude. During
startup, the value for the maximum frequency step size is greater than during
steady state
operation; it is, for example, set to 8 Hz. If the phase is positive, it is an
indication that the
running frequency is below the resonant frequency of the transducer and needs
to be increased. If
the phase is negative, it is an indication the running frequency is above the
resonant frequency
and the running frequency should be decreased. If the phase is close to zero,
the running
frequency is close to the resonant frequency of the transducer 902 and
waveguide 1502. The
46
CA 02750482 2011-08-25
numerically controlled oscillator ("NCO-) 1008 utilizing direct digital
synthesis ("DDS") is used
to change the frequency at step 7240.
TABLE 2
Gain constant: PID0 PID, PID2 PID3-PIDõ PIDõ- PID3 PID2 PID1
Driving frequency: fnun fres fmax
Phase (sine func , 90 shift): +1 +0.6 +0.4 +0.1 +.03 0 -
0.2 -0.4 -0.6 -0.8 -1
[00221] The DDS 2200 (see FIG. 22) provides synchronized operation of hardware
with the
oscillation frequency. In other words, to the main processor 914, it appears
as though the
frequency is constant. Here, the clock frequency of the main processor 914 is
a multiple of the
oscillation frequency. The invention alters the PWM frequency in a unique and
novel way. With
the invention, PWM is performed inside the main processor 914. Because of
this, the present
invention actually increases/decreases the frequency of the main processor 914
¨ which has not
been done before. The A/D converter 908 adjustments are automatic as well
because the A/D
converter 908 exists inside the microcontroller 1006. This inventive technique
can be analogized
to a singer adjusting a speed of a metronome to match the singer's tempo
rather than, as is
conventionally done, the singer changing her/his tempo to match the metronome.
[00222] At anytime during operation of the device, if the frequency reaches a
pre-set minimum
or maximum frequency limit, fifõõ and fma,õ respectively, the generator 904
turns off and a fault
condition is triggered, as shown in step 7242. Exemplary lower and upper
frequency limits for
the invention are 54 kHz and 58 kHz, respectively. A number of various
conditions can cause
the frequency to reach the minimum or maximum limit, including breakage of a
component (such
as the waveguide 1502) or a situation in which the waveguide 1502 is under
such a heavy load
that the device is not able to input the amount of power needed to find
resonance.
[00223] Once frequency lock is achieved, the transition begins into steady
state operation.
47
CA 02750482 2011-08-25
[00224] VIII. STEADY STATE OPERATION
[00225] During steady state operation, the objective is to maintain the
transducer and waveguide
at resonant frequency and to control the amplitude in response to any drifting
that occurs as a
result of a load on the waveguide 1502 during use of the device. When the
transducer 902 and
waveguide 1502 are driven at their composite resonant frequency, they produce
a large amount of
mechanical motion. The electrical energy from the battery is, in this state,
converted into a high
voltage AC waveform that drives the transducer 902. The frequency of this
waveform should be
the same as the resonant frequency of the waveguide 1502 and transducer 902,
and the magnitude
of the waveform should be the value that produces the proper amount of
mechanical motion.
[00226] a. Amplitude Control
[00227] At resonance, the amplitude is approximately proportional to the
transducer current, and
the transducer current is approximately proportional to the input current to
the push/pull
amplifier 1010. With constant current operation to maintain constant
amplitude, the output
voltage will vary with a varying load. In other words, the voltage will
increase if the output
power requirement increases and vice versa.
[00228] As described above in relation to the startup process, shown in FIG.
26 are two control
loops, an inner, current control loop 2601 and an outer, amplitude control
loop 2602 for uniquely
regulating the amplitude of the driving wave input to the transducer 902. The
current control
loop 2601 regulates the current from the battery assembly 301 going into the
push/pull amplifier
1010. The amplitude control loop 2602 compensates for load differences or any
other changes
that occur in the transducer and/or waveguide. To accomplish this goal, the
amplitude control
loop 2602 utilizes the motional feedback signal to generate the desired
reference current level,
"ref," that is used by the current control loop 2601 to alter the output
voltage of the DC-DC
converter as described above. To avoid interference-type interactions between
the two loops, the
current control loop 2601 operates at a higher frequency than the amplitude
control loop 2602,
e.g., approximately 300 KHz. The amplitude control loop 2602 typically
operates, for example,
at a frequency of 250 Hz.
48
CA 02750482 2011-08-25
[00229] To determine the desired reference current level, 'ref, the present
amplitude value is
subtracted from the desired "target amplitude" to generate an amplitude
percent error signal.
This amplitude percent error signal is the input into the PID control
algorithm of the amplitude
control loop 2601 for generating the new, desired reference current level
"'ref," based upon the
operating conditions being experienced by the transducer 902 and waveguide
1502 at that
particular time. In other words, the amplitude control loop 2602 changes the
target or reference
current value for the CLA 912 of the current control loop 2601 to reach the
desired amplitude
based on the percent error calculation. In this way, the output power is
altered based on the
variable need of the transducer 902 and waveguide 1502. The main processor
1118 of the battery
controller 703 checks the new reference current value to make sure that it is
not greater than the
maximum output current value.
[00230] Based upon the new target or reference current value, 'ref, that is
set by the amplitude
control loop 2602, the current control loop 2601 proceeds to change the output
voltage and input
current to the push/pull amplifier 1010. A measurement of the actual current
level 2603 of the
battery pack output is fed into the ADC 1120 of the battery microcontroller
1106 (shown in FIG.
11). The CLA 1116 takes the value from the ADC 1120 and subtracts it from the
target or
reference input current level 'ref to generate the current error signal. As
described above, the
CLA 1116 uses the PID control algorithm to compute a new duty cycle value for
the PWMs that
are driving the two-phase buck converter 1114. The CLA 1116 also computes a
maximum PWM
duty cycle to limit the output voltage. The algorithm to compute the maximum
duty cycle uses
the measured battery voltage and assumes the buck converter 1114 is operating
in continuous
conduction mode.
[00231] It is noted that, by utilizing amplitude control, rather than only
looking at the current for
steadying the amplitude, the present invention uniquely allows for finely
adjusting the output of
the transducer based on the motion feedback signal, achieving a more precise
amplitude control.
The use of a current control loop allows for faster initial response that
would not be possible with
amplitude control alone. Also, having the two loops provides for redundancy
and individual
calibration of the transducer and generator during manufacture, which can be
referred to as a
"calibration factor." In effect, two control loops are being used to regulate
the amplitude of the
driving wave input to the transducer, which provides synchronized operation of
the hardware
49
CA 02750482 2011-08-25
with the oscillation frequency. Redundancy is useful to ensure the device is
operating correctly.
A malfunction in one loop will usually be detectable because the other loop
will be unable to
operate properly and the improper operation of either loop is usually
detectable. Improper
operation can be caused by a hardware fault. The proper operation of both
loops requires
measurement of both current and amplitude. Different hardware is used to
measure amplitude
and current. In one embodiment the battery microcontroller 1106 measure
current and the TAG
microcontroller 1006 measures amplitude.
[00232] b. Frequency Control
[00233] In a similar operation to the initial frequency lock performed during
the startup process,
the main processor 914 of the generator 904 uses the results of the DFT
calculation to adjust the
running frequency of the generator 904 based on the phase of the motional
feedback signal in
order to maintain a resonant frequency during steady state operation. The
motional feedback
signal from the bridge circuit is proportional to and in phase with the motion
of the transducer
902 and waveguide 1502. When the motional feedback signal is in phase with the
output of the
push/pull switching amplifier 1010, the system is operating at the series
resonance. Again, the
phase and magnitude of the motional feedback signal is computed using a
Discrete Fourier
Transform ("DFT"). The phase reference for the DFT computation is the drive
signal for the
push/pull amplifier 1010. The frequency is, then, simply changed to cause the
push/pull drive
signal to be in phase with the motional feedback signal.
[00234] The DFT calculation is simplified and made more accurate if the ADC
sample time
interval is exactly an integer multiple of the output frequency period. This
technique is referred
to herein as "coherent sampling." In one exemplary embodiment, the signals are
sampled 12
times per output cycle such that the CLA 912 is sampling the motional feedback
signal at 12
times the ultrasonic frequency. With coherent sampling, there are exactly 12
samples per cycle
with each occurring at the same point in time relative to the phase of the
drive signal. As shown
in FIG. 9, the ADC sample clock is generated internally in the TAG
microcontroller's 1006
system clock 916. Accordingly, for coherent sampling, the system clock 916
needs to be
synchronized to the output. The PWM signal driving the metal-oxide field-
effect transistors
(MOSFETs) that, in turn, generate the output waveform, is also generated
internally from the
system clock 916. One exemplary embodiment of the present invention generates
the system
CA 02750482 2011-08-25
clock 916 from the DDS 1008. Advantageously, as the output frequency changes,
the system
clock 916 also changes.
[00235] It is also desirable not to sample shortly after the MOSFETs are
switched on or off
This is when there is the largest amount of noise present in the system.
Offsetting the sample
time to avoid sampling shortly after the MOSFETs switch on or off minimizes
the affect of
transistor switching noise on the ADC sample. The two PWM outputs employ a
deadband to
ensure that both MOSFETs are never activated at the same time.
[00236] X. SIMPLIFIED CIRCUIT BLOCK DIAGRAM
[00237] FIG. 27 shows a simplified block circuit diagram illustrating another
exemplary
electrical embodiment of the present invention, which includes a
microprocessor 2702, a clock
2730, a memory 2726, a power supply 2704 (e.g., a battery), a switch 2706
(e.g., a MOSFET
power switch), a drive circuit 2708 (PLL), a transformer 2710, a signal
smoothing circuit 2712
(also referred to as a matching circuit and can be, e.g., a tank circuit), a
sensing circuit 2714, a
transducer 902, and a waveguide assembly 304, which terminates at an
ultrasonic cutting blade
1520, referred to herein simply as the waveguide 1502.
[00238] One feature of the present invention that severs dependency on high
voltage (120 VAC)
input power (a characteristic of all prior-art ultrasonic cutting devices) is
the utilization of low-
voltage switching throughout the wave-forming process and the amplification of
the driving
signal only directly before the transformer stage. For this reason, in one
exemplary embodiment
of the present invention, power is derived from only a battery, or a group of
batteries, small
enough to fit either within the handle assembly 302. State-of-the-art battery
technology provides
powerful batteries of a few centimeters in height and width and a few
millimeters in depth. By
combining the features of the present invention to provide an entirely self-
contained and self-
powered ultrasonic device, the capital outlay of the countertop box 202 is
entirely eliminated ¨
resulting in a significant reduction of manufacturing cost.
[00239] The output of the battery 2704 is fed to and powers the processor
2702. The processor
2702 receives and outputs signals and, as will be described below, functions
according to custom
logic or in accordance with computer programs that are executed by the
processor 2702. The
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CA 02750482 2011-08-25
device 2700 can also include a main memory 2726, preferably, random access
memory (RAM),
that stores computer-readable instructions and data.
[00240] The output of the battery 2704 also is directed to a switch 2706
having a duty cycle
controlled by the processor 2702. By controlling the on-time for the switch
2706, the processor
2702 is able to dictate the total amount of power that is ultimately delivered
to the transducer
2716. In one exemplary embodiment, the switch 2706 is a MOSFET, although other
switches
and switching configurations are adaptable as well. The output of the switch
2706 is fed to a
drive circuit 2708 that contains, for example, a phase detecting PLL and/or a
low-pass filter
and/or a voltage-controlled oscillator. The output of the switch 2706 is
sampled by the processor
2702 to determine the voltage and current of the output signal (labeled in
FIG. 27 as AD2 V,õ and
AD3
respectively). These values are used in a feedback architecture to adjust the
pulse width
modulation of the switch 2706. For instance, the duty cycle of the switch 2706
can vary from
about 20% to about 80%, depending on the desired and actual output from the
switch 2706.
[00241] The drive circuit 2708, which receives the signal from the switch
2706, includes an
oscillatory circuit that turns the output of the switch 2706 into an
electrical signal having a single
ultrasonic frequency, e.g., 55 kHz (referred to as VCO in FIG. 27). As
explained above, a
smoothed-out version of this ultrasonic waveform is ultimately fed to the
transducer 902 to
produce a resonant sine wave along the waveguide 1502.
[00242] At the output of the drive circuit 2708 is a transformer 2710 that is
able to step up the
low voltage signal(s) to a higher voltage. It is noted that all upstream
switching, prior to the
transformer 2710, is performed at low (i.e., battery driven) voltages,
something that, to date, has
not been possible for ultrasonic cutting and cautery devices. This is at least
partially due to the
fact that the device advantageously uses low on-resistance MOSFET switching
devices. Low on-
resistance MOSFET switches are advantageous, as they produce less heat than
traditional
MOSFET device and allow higher current to pass through. Therefore, the
switching stage (pre-
transformer) can be characterized as low voltage/high current. In one
exemplary embodiment of
the present invention, the transformer 2710 steps up the battery voltage to
120V RMS.
Transformers are known in the art and are, therefore, not explained here in
detail.
52
CA 02750482 2011-08-25
[00243] In each of the circuit configurations described and shown in FIGS. 3-
12, 16-21, and 27,
circuit component degradation can negatively impact the entire circuit's
performance. One factor
that directly affects component performance is heat. Known circuits generally
monitor switching
temperatures (e.g., MOSFET temperatures).
However, because of the technological
advancements in MOSFET designs, and the corresponding reduction in size,
MOSFET
temperatures are no longer a valid indicator of circuit loads and heat. For
this reason, according
to an exemplary embodiment, the present invention senses with a sensing
circuit 2714 the
temperature of the transformer 2710. This temperature sensing is advantageous
as the
transformer 2710 is run at or very close to its maximum temperature during use
of the device.
Additional temperature will cause the core material, e.g., the ferrite, to
break down and
permanent damage can occur. The present invention can respond to a maximum
temperature of
the transformer 2710 by, for example, reducing the driving power in the
transformer 2710,
signaling the user, turning the power off completely, pulsing the power, or
other appropriate
responses.
[00244] In one exemplary embodiment of the invention, the processor 2702 is
communicatively
coupled to the end effector 118, which is used to place material in physical
contact with the blade
portion 116 of the waveguide 114, e.g., the clamping mechanism shown in FIG.
1. Sensors are
provided that measure, at the end effector, a clamping force value (existing
within a known
range) and, based upon the received clamping force value, the processor 2702
varies the motional
voltage Vm. Because high force values combined with a set motional rate can
result in high
blade temperatures, a temperature sensor 2736 can be communicatively coupled
to the processor
2702, where the processor 2702 is operable to receive and interpret a signal
indicating a current
temperature of the blade from the temperature sensor 2736 and to determine a
target frequency of
blade movement based upon the received temperature.
[00245] According to an exemplary embodiment of the present invention, the PLL
2708, which
is coupled to the processor 2702, is able to determine a frequency of
waveguide movement and
communicate that frequency to the processor 2702. The processor 2702 stores
this frequency
value in the memory 2726 when the device is turned off By reading the clock
2730, the
processor 2702 is able to determine an elapsed time after the device is shut
off and retrieve the
last frequency of waveguide movement if the elapsed time is less than a
predetermined value.
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CA 02750482 2011-08-25
The device can then start up at the last frequency, which, presumably, is the
optimum frequency
for the current load.
[00246] XI. BATTERY ASSEMBLY¨MECHANICAL
[00247] FIG. 28 shows the battery assembly 301 separate from the handle
assembly 302. The
battery assembly 301 includes an outer shell 2802 that, in the exemplary
embodiment shown in
FIG. 28, includes a first half 2802a and a second half 2802b. There is,
however, no requirement
that the shell 2802 be provided in two identical halves. In accordance with an
embodiment of the
present invention, when the outer shell 2802 is provided in two halves, the
first half 2802a can be
ultrasonically welded to the second half 2802b in a clamshell configuration.
Ultrasonically
welding the two halves of the shell 2802 eliminates the need for gaskets while
providing a
"hermetic" seal between the components within the shell 2802 and the
environment. A
"hermetic" seal, as used herein, indicates a seal that sufficiently isolates a
compartment (e.g.,
interior of the shell 2802) and components disposed therein from a sterile
field of an operating
environment into which the device has been introduced so that no contaminants
from one side of
the seal are able to transfer to the other side of the seal. This seal is at
least gas-tight, thereby
preventing intrusion of air, water, vapor phase H202, etc.
[00248] FIG. 28 also shows a multi-lead battery terminal assembly 2804, which
is an interface
that electrically couples the components within the battery assembly 301 to an
electrical interface
of the handle assembly 302. It is through the handle assembly 302 that the
battery assembly 301
is able to electrically couple with the TAG assembly 303 of the present
invention. As is
explained above, the battery assembly 301, through the multi-lead battery
terminal assembly
2804, provides power to the inventive ultrasonic surgical cautery assembly
300, as well as other
functionality described herein. The multi-lead battery terminal assembly 2804
includes a
plurality of contacts pads 2806a-n, each one capable of separately
electrically connecting a
terminal within the battery assembly 301 to another terminal provided by a
docking bay (see FIG.
34) of the handle assembly 302. One example of such electrical connections
coupled to the
plurality of contact pads 2806a-n is shown in FIG. 6 as power and
communication signal paths
601a-n. In the exemplary embodiment of the multi-lead battery terminal
assembly 2804, sixteen
different contact pads are shown. This number is merely illustrative.
54
CA 02750482 2011-08-25
[00249] FIG. 29 provides a view of the underside of the multi-lead battery
terminal assembly
2804. In this view, it can be seen that the plurality of contact pads 2806a-n
of the multi-lead
battery terminal assembly 2804 include a corresponding plurality of interior
contact pins 2906a-
n. Each contact pin 2906 provides a direct electrical coupling to a
corresponding one of the
contact pads 2806.
[00250] In the particular embodiment shown in FIGS. 28-33, the multi-lead
battery terminal
assembly 2804 is potted between the clam shell halves 2802a and 2802b of the
shell 2802. More
particularly, FIG. 29 provides a view of the multi-lead battery terminal
assembly 2804 positioned
inside an upper portion of the first shell half 2802a of the battery assembly
301. As is shown in
the figure, an upper portion of the first shell half 2802a forms a mouth 2902
that accepts an outer
peripheral edge 2904 of the multi-lead battery terminal assembly 2804.
[00251] FIG. 30 provides an additional view of the interior of the first shell
half 2802a with the
multi-lead battery terminal assembly 2804 inserted within the mouth 2902 of
the first shell half
2802a and a first circuit board 3002 having a plurality of contact pads 3006
coupled to the
contact pins 2906 of the multi-lead battery terminal assembly 2804. The
battery assembly 301,
according to exemplary embodiments of the present invention, includes, as is
shown in FIG. 31,
in addition to the first circuit board 3002, additional circuit boards 3102
and 3104.
[00252] In accordance with one exemplary embodiment of the present invention,
the multi-lead
battery terminal assembly 2804 comprises a flex circuit that converts the
illustrated 4 x 4 array of
contact pads 2006a-n to two 1 x 8 arrays of conductors that are coupled to one
or more of the
circuit boards 3002, 3102, 3104.
[00253] Further, more than or less than three circuit boards is possible to
provide expanded or
limited functionality. According to exemplary embodiments of the present
invention, each
circuit board 3002, 3102, and 3104 provides a specific function. For instance,
circuit board 3002
can provide the components for carrying out the battery protection circuitry
702 shown in FIG. 7.
Similarly, the circuit board 3102 can provide the components for carrying out
the battery
controller 703, also shown in FIG. 7. The circuit board 3104 can, for example,
provide high
power buck controller components. Finally, the battery protection circuitry
702 can provide
connection paths for coupling the battery cells 701a-n shown in FIGS. 7 and
31.
CA 02750482 2011-08-25
[00254] Another advantage of a removable battery assembly 301 is realized when
lithium-ion
(Li) batteries are used. As previously stated, lithium batteries should not be
charged in a parallel
configuration of multiple cells. This is because, as the voltage increases in
a particular cell, it
begins to accept additional charge faster than the other lower-voltage cells.
Therefore, each cell
must be monitored so that a charge to that cell can be controlled
individually. When a lithium
battery is formed from a group of cells 701a-n, a multitude of wires extending
from the exterior
of the device to the batteries 701a-n is needed (at least one additional wire
for each battery cell
beyond the first). By having a removable battery assembly 301, each battery
cell 701a-n can, in
one exemplary embodiment, have its own exposed set of contacts and, when the
battery assembly
301 is not present inside the handle assembly 302, each set of contacts can be
coupled to a
corresponding set of contacts in an external, non-sterile, battery-charging
device. In another
exemplary embodiment, each battery cell 701a-n can be electrically connected
to the battery
protection circuitry 702 to allow the battery protection circuitry 702 to
control and regulate
recharging of each cell 701a-n.
[00255] Turning now to FIG. 33, at least one additional novel feature of the
present invention is
clearly illustrated. The battery assembly 301 shown in FIG. 33 illustrates a
fully assembled
battery assembly 301 that has been, for instance, ultrasonically welded so
that the two shell
halves 2802a and 2802b, as well as the potted multi-lead battery terminal
assembly 2804, provide
a hermetic seal between the environment and the interior of the battery
assembly 301. Although
shown in several of the previous drawings, FIG. 33 illustrates an inventive
catch 3300, which is
formed by an extended portion of the shell 2802 that is shaped by a general
longitudinal void
3302 directly under the catch 3300, both being located at an upper portion of
the exterior of the
shell 2802. The catch 3300 is shaped to mate with a receiver 3400 in a lower
battery dock 3401
of the handle assembly 302, which is shown in FIG. 34.
[00256] FIG. 35 illustrates an underside of the handle assembly 302 and
provides an improved
view of the receiver 3400 and the battery dock 3401. As is can be seen in FIG.
35, the receiver
3400 extends from the battery dock 3401 (formed by a handle shell 3500) and is
shaped to mate
with, i.e., fit within, the void 3302 of the battery assembly 301. In
addition, the receiver 3400 is
in close proximity to a multi-lead handle terminal assembly 3502, which
includes a plurality of
handle-connection pins 3504a-n. In the exemplary embodiment shown in FIG. 35,
each handle
56
CA 02750482 2011-08-25
contact pin in the multi-lead handle terminal assembly 3502 is a spring-type
contact pin that is
capable of being compressed while exerting an amount of force in a direction
opposite the
compression force and, thereby, maintaining a positive electrical connection
between the handle-
connection pin 3504a-n and the object applying the force. In addition, the
handle-connection
pins 3504a-n of the multi-lead handle terminal assembly 3502 are spaced so
that each of the
handle-connection pins 3504a-n physically aligns with a respective one of the
contact pads
2806a-n of the multi-lead battery terminal assembly 2804.
[00257] To couple the inventive battery assembly 301 to the inventive handle
assembly 302, the
catch 3300 is contacted with the receiver 3400, as is shown in FIG. 36, and
the battery assembly
301 is rotated with respect to the handle assembly 302, as is shown in the
progression from FIG.
36 to FIG. 37. Although not limited to the exemplary embodiments shown in the
figures of the
instant specification, the physical shapes of the catch 3300 and receiver 3400
shown in FIGS. 33-
35 (particularly the rounded corners 3305 shown in FIG. 33) cause the battery
assembly 301 to
align itself with the handle assembly 302 virtually regardless of the angle to
which the battery
assembly 301 approaches the receiver 3400, as long as the catch 3300 and
receiver 3400 are in
physical contact with each other. With any rotation of the battery assembly
301 between the
position shown in FIG. 36 and the position shown in FIG. 37, the catch 3300,
or rather, the void
3302, automatically seats upon the receiver 3400. This means that a user in
the sterile field can
easily connect the battery assembly 301 to the handle assembly 302 and,
especially, can do so
without actually viewing the two parts during connection efforts.
[00258] In accordance with one exemplary embodiment of the present invention,
the multi-lead
handle terminal assembly 3502, as shown in FIG. 35, includes a gasket 3512
that surrounds the
handle-connection pins 3504a-n and is sealed to a flex circuit board 3514 that
supports the
handle-connection pins 3504a-n. In one exemplary embodiment, the gasket 3512
is part of a
rigid-flex circuit that includes the flex circuit board 3514 as well as the
handle-connection pins
3504a-n. A portion of the flex circuit board 3514 can be made relatively rigid
or stiffer as
compared to the rest of the flex circuit board 3514. When the gasket 3512 is
compressed during
connection of the battery assembly 301 to the handle assembly 302, rigid
portions of the flex
circuit board 3514 adjacent the gasket 3512 support the gasket 3512 and allow
the gasket 3512 to
be compressed without substantial movement when the battery assembly 301 is
coupled to the
57
CA 02750482 2011-08-25
handle assembly 302. When the multi-lead battery terminal assembly 2804 and
the multi-lead
handle terminal assembly 3502 are placed together, as shown in FIGS. 59 and
60, a seal exists
between an outer periphery 3312 of the multi-lead battery terminal assembly
2804 and the gasket
3512 of the multi-lead handle terminal assembly 3502. The seal prevents
moisture from
penetrating the interior of the gasket 3512, i.e., reaching the handle-
connection pins 3504a-n of
the multi-lead handle terminal assembly 3502 or the contacts pads 2806a-n of
the multi-lead
battery terminal assembly 2804.
[00259] As shown in FIG. 56 and explained in detail below, the rigid-flex
circuit of the handle
assembly 302 electrically couples the handle-connection pins 3504a-n to the
handle assembly's
TAG electrical connector 5602.
[00260] Referring briefly back to FIG. 35, the handle body 3500 of the handle
assembly 302 is
provided with an extended battery securing portion 3506. The extended battery
securing portion
3506 is on a side of the multi-lead handle terminal assembly 3502 opposite the
receiver 3400. It
is noted that the particular exemplary embodiment of the handle-securing
portion shown in FIG.
35 includes a pair of voids 3508 and 3510, which are not necessary to complete
the battery-
handle securing process. Referring now to FIG. 38, an additional feature of
the battery assembly
301 is shown. In this view, a pair of bosses 3802, 3804 can be seen on an
exterior side of the
battery assembly shell 2802. The bosses 3802, 3804 are spaced and positioned
to mate with the
voids 3508, 3510 in the extended battery securing portion 3506 of the handle
body 3500. This
mating position is illustrated in FIG. 37. Referring still to FIG. 38, it can
be seen that each of the
bosses 3802, 3804 are provided with a sloped upper portion 3816 and an
opposing sharp-edge
bottom portion 3818. The sloped upper portion 3816 allows the bosses 3802,
3804 to easily slip
into the voids 3508, 3510 in the extended battery securing portion 3506 of the
handle assembly
302 when the battery assembly 301 is being secured to the handle assembly 302.
The sharp-edge
bottom portions 3818 secure and allow the bosses 3802, 3804 to remain seated
within the
extended battery securing portion 3506 of the handle assembly 302.
[00261] The combination of the mating between the catch 3300 and receiver 3400
at one side of
the battery assembly 301 and the mating between the bosses 3802, 3804 and the
voids 3508,
3510, respectively, at the other side of the battery assembly 301 provides a
solid and secure
attachment of the battery assembly 301 to the handle assembly 302 (see also
FIGS. 3 and 37). In
58
CA 02750482 2011-08-25
an exemplary embodiment, the two bosses 3802, 3804 are spaced as far apart
from each other as
is practical. This spacing improves stability of the attachment between the
battery assembly 301
and the handle assembly 302.
[00262] FIG. 38 also illustrates a release mechanism 3806 coupled to the
exterior of the battery
assembly shell 2802. The release mechanism 3806 is provided with peripheral
edges 3808 that
are secured by and slide within a pair of corresponding channels 3810, 3812
formed within the
same exterior side of the battery assembly shell 2802 as the bosses 3802,
3804. The release
mechanism 3806 has a sloped nose region 3814 that is operable for moving
toward and away
from the bosses 3802 and 3804 and, in the particular embodiment shown in FIG.
38, extends
between the bosses 3802 and 3804 when the release mechanism 3806 is slid in an
upwardly
direction.
[00263] When the battery assembly 301 is securely coupled to the handle
assembly 302, as is
shown in FIG. 37, the release mechanism 3806 remains in a position within the
channels 3810,
3812 that is furthest away from the handle assembly 302. When a user desires
to remove the
battery assembly 301 from the handle assembly 302, the release mechanism 3806
is slid within
the channels 3810, 3812 in a direction toward the handle assembly 302. This
sliding action
causes the sloped nose region 3814 to enter the area between the battery
assembly 301 and the
lowermost portion of the extended battery securing portion 3506. As the sloped
nose region
3814 moves forward, the extended battery securing portion 3506 rides up the
sloped nose region
3814 and flexes away from the battery assembly 301. Stated differently, the
extended battery
securing portion 3506 bends away from the multi-lead handle terminal assembly
3502 and
receiver 3400.
[00264] Once the extended battery securing portion 3506 flexes to a certain
degree, the bottom
edges 3802a-3802b of the bosses 3802 and 3804 no longer engage with the voids
3508 and 3510
and the battery assembly 301 can easily be rotated from the orientation shown
in FIG. 37 to that
shown in FIG. 36 and, ultimately, separated from the handle assembly 302. The
release
mechanism 3806 is, of course, only one example of a mechanism that secures the
battery
assembly 301 to and releases the battery assembly 301 from the handle assembly
302. The
release mechanism 3806 is advantageous in that it renders unintended
detachment very unlikely.
To release the battery assembly 301, an operator needs to move the release
mechanism 3806
59
CA 02750482 2011-08-25
toward the handle while, at the same time, rotating the battery assembly 301
away from the
handle assembly 302. These two oppositely-directed forces/actions are very
unlikely to occur
simultaneously unless they are performed intentionally. Application of these
different forces also
requires the user's hands to be in a position different than an in-use
position during surgery.
Such a configuration virtually ensures that accidental separation of the
battery assembly 301 and
handle assembly 302 does not occur.
[00265] The present invention also provides a significant advantage over prior
art devices in the
way the electrical connection between the multi-lead handle terminal assembly
3502 and the
multi-lead battery terminal assembly 2804 is formed. More specifically,
looking again to FIG.
33, it can be seen that, in the illustrated exemplary embodiment of the multi-
lead battery terminal
assembly 2804, sixteen contact pads 2806 are present -- the contact pads 2806a-
d forming a first
row 3304, contact pads 2806e-h forming a second row 3306, contact pads 2806i-1
forming a third
row 3308, and contact pads 2806m-p forming a fourth row 3310.
[00266] Similarly, as is shown in FIGS. 34 and 35, the multi-lead handle
terminal assembly
3502 includes a plurality of handle-connection pins 3504a-n (only twelve of
the sixteen pins
3504a-n are shown in the view of FIG. 35). The handle contact pins are
configured so that, when
the battery assembly 301 is coupled to the handle assembly 302, each handle-
connection pin
3504a-n is aligned with an individual one of the contact pads 2806. Therefore,
the handle-
connection pins 3504a-n are also disposed, in the particular embodiment shown
in the drawings,
in four rows 3404, 3406, 3408, and 3410.
[00267] When the battery assembly 301 is to be attached to the handle assembly
302, the catch
3300 is first placed in contact with the receiver 3400 and the battery
assembly 301 is then rotated
toward the extended battery securing portion 3506 until the bosses 3802, 3804,
respectively,
engage the voids 3508, 3510 in the extended battery securing portion 3506. One
significant
result of the rotation is that the physical/electrical connection between the
multi-lead handle
terminal assembly 3502 and the multi-lead battery terminal assembly 2804
occurs sequentially,
one row at a time, starting with battery row 3304 and handle row 3404.
[00268] According to an exemplary embodiment of the present invention, the
first battery row
3304 includes a grounding contact pad and the last battery row 3410 includes
at least one power
CA 02750482 2011-08-25
contact pad. Therefore, the first contact between the multi-lead battery
terminal assembly 2804
and the multi-lead handle terminal assembly 3502 is a grounding connection and
the last is the
power connection. Installation of the battery assembly 301 will not cause a
spark because the
ground contact of the battery assembly 301 is a distance away from the last
row 3410 of the
multi-lead handle terminal assembly 3502 when the powered connection is made.
As the battery
assembly 301 is rotated into an attachment position (shown in FIG. 37), each
battery row 3304,
3306, 3308, 3310 sequentially makes contact with each handle row 3404, 3406,
3408, 3410,
respectively, but the power contact(s) is(are) only connected after a row
having at least one
grounding contact has been connected. In other words, as the battery assembly
301 is installed
into the handle assembly 302, the battery assembly 301 is advantageously
grounded before any
power contacts are brought into contact with any portion of the handle
assembly 302 -- a
significant advantage over prior-art device power supply couples. In all known
devices, the
contacts supplying power (i.e., electric mains) are coupled simultaneous to
other couplings, or
randomly, depending on the approach orientation of the electric plug. This
prior-art coupling
leaves sparking or arcing as a persistent possibility. With the present
invention, however, the
possibility of sparking or arcing that is present in the prior art is entirely
eliminated.
[00269] In addition, in accordance with one exemplary embodiment of the
present invention,
one or more pins in any of the first, 3404, the second 3406, the third 3408,
or the last row 3410
of the handle-connection pins 3504a-n are coupled to a battery presence
detection circuit 3104.
In particular, one of the contacts in the last row 3410 is used as a present
pad. The battery
presence detection circuit 3104, after detecting the proper connection of the
grounding pin(s) and
the present pin of the multi-lead handle terminal assembly 3502 to the multi-
lead battery terminal
assembly 2804, allows operation of the ultrasonic surgical assembly 300. In
the embodiment
where the battery present detection pad(s) is/are only in the last row, i.e.,
furthest away from the
receiver 3400, the handle assembly 302 will not alter/change states until the
battery assembly 301
is fully and securely installed, i.e., all contacts are properly connected.
This advantageous feature
prevents any improper operation of the overall assembly. Similarly, when
disconnecting the
battery assembly 301, the last row 3410 is the first row disconnected from the
handle-connection
pins 3504a-n. Therefore, the device immediately responds to the absence of the
battery assembly
301 from the handle assembly 302.
61
CA 02750482 2011-08-25
[00270] In the exemplary embodiment, the battery protection circuit 702, i.e.,
the fuel gauge,
monitors the present pad and waits for it to be grounded before powering the
microprocessor
1006 within the TAG assembly 303. To do this, of course, the TAG assembly 303
must also be
coupled to the handle assembly 302. More particularly, the TAG assembly 303
must be
electrically coupled to the handle assembly's TAG electrical connector 5602.
Once the TAG
assembly 303 is coupled to the handle assembly's TAG electrical connector 5602
(see, e.g.,
FIGS. 36 and 37) and the battery assembly 301 is properly coupled to the multi-
lead handle
terminal assembly 3502 (see, e.g., the configuration shown in FIG. 37),
communication between
the battery assembly 301 and the TAG assembly 302 occurs. After such
communication is
established, the device is ready for use and the battery controller 703 can
signal a "ready-for-use"
state to the user, for example, by generating an indicative tone at the buzzer
802 within the
handle assembly 302 and/or generating a visual indicator at the LEDs 906.
[00271] In one exemplary embodiment for establishing this communication, the
battery
protection circuit 702 senses the presence of a proper connection between the
battery assembly
301 and the handle assembly 302 by periodically pulsing a low-voltage signal
to the present pad.
The battery protection circuit 702 monitors the present pad for a connection
to ground, which
ground is provided by the handle assembly 302 once the battery assembly 301 is
properly
connected thereto. However, because the battery assembly 301 may be submerged
in a solution,
for example, water during cleaning, it is advantageous for the battery
assembly 301 not to sense a
false ground condition as if the battery assembly 301 has been properly
connected to the handle
assembly 301 when the ground condition is only due to the solution
electrically coupling the
present pad to ground. For this reason, embodiments of the present invention
provide a
comparator that monitors the impedance between the present pad and ground. The
comparator
compares the impedance of a coupling between the present pad and ground to the
reference
impedance so that only when the impedance is less than a threshold impedance,
i.e., less than that
of a solution, will the battery assembly 301 operate.
[00272] The illustrated design of the multi-lead handle terminal assembly 3502
provides even
further advantages over the prior art. In particular, the inventive handle-
connection pins 3504a-n,
shown in the enlarged partial perspective view of FIG. 39, provide a physical
connection along
with a lateral displacement that ensures removal of any foreign substances
from the contact
62
CA 02750482 2011-08-25
region where the handle-connection pins 3504a-n of the multi-lead handle
terminal assembly
3502 meet the contact pads 2806a-n of the multi-lead battery terminal assembly
2804.
Specifically, FIG. 39 shows the first handle-connection pin 3504a in its at-
rest, non-contact state.
That is, the handle-connection pin 3504a has a spring force that places and
retains it in the
natural resting shape shown in FIG. 39. However, when the multi-lead battery
terminal assembly
2804 is fully mated with the multi-lead handle terminal assembly 3502, the
handle-connection
pins 3504a-n compress. This compressed state is shown, for example, by handle-
connection pins
3504b and 3504f in FIG. 39.
[00273] The compression placed on the handle-connection pin 3504a-n by the
contact pad 2806
not only provides positive pressure to retain the electrical connection, but
also causes the
connecting surface of each handle-connection pin 3504a-n to move a distance D
with respect to
the longitudinal extent of the pin 3504. This distance D is illustrated in
FIG. 39 by a first line
3901 showing where an apex of a connecting surface of a first handle-
connection pin 3504e
exists when the pin 3504e is in its uncompressed state. A second line 3902
shows where the
apex of the connecting surface of the neighboring second handle-connection pin
3504f exists
when the pin 3504f is compressed. The difference between the two lines defines
a longitudinal
distance D that the connecting surface of each pin 3504a-n translates when
compressed. This
movement is initiated when the handle-connection pin 3504a-n and the
respective contact pad
2806 first make contact and continues until the battery assembly 301 is fully
seated between the
receiver 3400 and the extended battery securing portion 3506, as shown in the
cutaway
perspective view FIG. 40. The translation movement of the handle-connection
pins 3504a-n
produces a swiping motion that effectively wipes the contact pad 2806 clean,
thus improving
electrical connection therebetween. This wiping effect can prove highly
advantageous when, for
instance, a battery needs to be replaced in an operating environment and
material, such as blood,
comes into contact with the contact pads 2806 or when the pads are corroded
from repeated use
or due to exposure to cleaning agents.
[00274] The view of FIG. 39 shows yet another advantageous feature of the
present invention.
In FIG. 39, it can be seen that the multi-lead handle terminal assembly 3502
features flanged
sides 3904 that protect the handle-connection pins 3504a-n of the handle
assembly 302.
63
CA 02750482 2011-08-25
[00275] A further advantage of the present invention is that the entire
battery assembly 301
can be sterilized. If there is a need for replacement during a medical
procedure, the battery
assembly can be easily replaced with a new sterile battery assembly. The gas-
tight construction
of the battery assembly 301 allows it to be sterilized, for example, using low-
temperature vapor
phase Hydrogen Peroxide (H202) as performed by the sterilization devices
manufactured by the
Steris Corporation and referred to under the trade name V-PRO or manufactured
by Advanced
Sterilization Products (ASP), division of Ethicon, Inc., a Johnson & Johnson
company, and
referred to under the trade name STERRADt. Because the Lithium cells of the
battery assembly
301 are damaged when heated above 60 C, non-heating sterilization commonly
used in hospitals
today makes the battery assembly 301 easily re-used in surgical environments.
[00276] a. Battery Pressure Valve
[00277] The battery assembly 301 of the present invention features yet another
inventive
feature. As shown in FIG. 37, the battery assembly 301 includes a pressure
valve 3702 that, as
will be explained below, prevents the influence of external atmospheric
pressure -- both positive
and negative -- on the battery assembly's internal pressure, while providing
for emergency
pressure relief for excess internal pressure, e.g., >30 psi. This valve 3702,
advantageously, has a
large enough opening to vent any internally accumulating gases quickly. Also
advantageously,
the inventive valve 3702 does not instantaneously open and close with small
changes in pressure,
as do some prior art venting devices. Instead, the opening and closing events
of the valve 3702
have several defined stages. In an exemplary configuration of the valve 3702,
during the first
stage (( 30 psi), the valve 3702 remains sealed, as shown in FIGS. 41 and 42,
and does not allow
gas flow into or out of the battery compartment. This exemplary embodiment can
be referred to
as a so-called poppet valve. In stage 2, once pressure has increased just
enough to counter the
force of a spring 4102 holding an 0-ring 4104 surrounding a poppet 4106
against a valve seat
4202, shown in the cutaway view of FIG. 42, fluid/gas will begin to escape
between the 0-ring
4104 and the seat 4202. In stage 3, pressure has pushed the valve 3702 open
enough to allow a
significant amount of fluid/gas to pass the seal 4104, 4202. This is enough to
measure
accurately. At this point, and up to stage 4, internal pressure has forced the
valve completely
open, i.e., the 0-ring 4104 has moved completely off of the seat 4202.
Additional pressure has
diminished effect on the flow because the valve cannot open further.
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[00278] In stage 5, pressure on the valve 3702 begins to decrease and the
poppet 4106 starts to
shut. As the poppet 4106 retracts, it follows the same sequence as occurred
during opening
through hysteresis (i.e., retardation of an effect when forces acting upon a
body are changed,
dictating that a lag in closing occurs). As a result, when the poppet 4106
begins its return, it lags
in position relative to the curve of FIG. 44 traversed when the poppet 4106
was opening. At
stage 6, the 0-ring 4104 just touches the seat 4202. The valve does not seal
at this point, as there
is no force pressing the 0-ring 4104 into the seat 4202. In step 7, the force
of the spring 4102
compresses the 0-ring 4104 with sufficient force to seal the valve shut. The
valve 3702 can now
return to stage 1, shown in FIGS. 41 and 42. For ease of testing the valve
3702, the poppet 4106
is formed with a tear-off handle 4108. In this exemplary configuration, a user
or leak-testing
fixture can grasp the handle 4108 and move the poppet 4106 out and back within
the valve dock
4204, here, shown located in one half of the outer shell 2802a or 2802b of the
battery assembly
301. When testing is finished, the user, for example, the manufacturer, can
tear off or otherwise
remove the handle 4108 to prevent further user-controlled poppet 4106
movement. Removal of
the handle 4108 is made easier with a narrowing 4110 formed at the base of the
handle 4108.
[00279] b. Smart Battery
[00280] In additional exemplary embodiments of the present invention, a smart
battery is used
to power the surgical ultrasonic surgical cautery assembly 300. However, the
smart battery is not
limited to the ultrasonic surgical cautery assembly 300 and, as will be
explained, can be used in a
variety of devices, which may or may not have power requirements (i.e.,
current and voltage) that
vary from one another. The smart battery, in accordance with an exemplary
embodiment of the
present invention, is advantageously able to identify the particular device to
which it is
electrically coupled. It does this through encrypted or unencrypted
identification methods. For
instance, a battery assembly 301 shown in FIG. 57 can have a connection
portion, such as portion
5702. The handle assembly 302 can also be provided with a device identifier
5704
communicatively coupled to the multi-lead handle terminal assembly 3502 and
operable to
communicate at least one piece of information about the handle assembly 302.
This information
can pertain to the number of times the handle assembly 302 has been used, the
number of times a
TAG assembly 303 (presently connected to the handle assembly 302) has been
used, the number
of times a waveguide assembly 304 (presently connected to the handle assembly
302) has been
CA 02750482 2011-08-25
used, the type of waveguide assembly 304 that is presently connected to the
handle assembly
302, the type or identity of the TAG assembly 303 that is presently connected
to the handle
assembly 302, or many other characteristics. When the smart battery assembly
301 is inserted in
the handle assembly 302, the connection portion 5702 within the smart battery
assembly 301
makes communicating contact with the device identifier 5704 of the handle
assembly 302. The
handle assembly 302, through hardware, software, or a combination thereof, is
able to transmit
information to the smart battery assembly 301 (whether by self-initiation or
in response to a
request from the battery assembly 301). This communicated identifier is
received by the
connection portion 5702 of the smart battery assembly 301. In one exemplary
embodiment, once
the smart battery assembly 301 receives the information, the communication
portion 5702 is
operable to control the output of the battery assembly 301 to comply with the
device's specific
power requirements.
[00281] In an exemplary embodiment, the communication portion 5702 includes a
processor,
such as processor 1118, and a memory, which may be separate or a single
component. The
processor 1118, in combination with the memory, is able to provide intelligent
power
management for the handheld ultrasonic surgical cautery assembly 300. This
embodiment is
particularly advantageous because an ultrasonic device, such as handheld
ultrasonic surgical
cautery assembly 300, has a power requirement (frequency, current, and
voltage) that may be
unique to the handheld ultrasonic surgical cautery assembly 300. In fact,
handheld ultrasonic
surgical cautery assembly 300 may have a particular power requirement or
limitation for one
dimension or type of waveguide 1502 and a second different power requirement
for a second
type of waveguide having a different dimension, shape, and/or configuration.
[00282] A smart battery 301 according to the invention, therefore, allows a
single battery
assembly to be used amongst several surgical devices. Because the smart
battery 301 is able to
identify to which device it is attached and is able to alter its output
accordingly, the operators of
various different surgical devices utilizing the smart battery 301 no longer
need be concerned
about which power source they are attempting to install within the electronic
device being used.
This is particularly advantageous in an operating environment where a battery
assembly needs to
be replaced in the middle of a complex surgical procedure.
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[00283] In a further exemplary embodiment, the smart battery 301 stores in a
memory 5706 a
record of each time a particular device is used. This record can be useful for
assessing the end of
a device's useful or permitted life. For instance, once a device is used 20
times, all such batteries
301 connected to the device will refuse to supply power thereto -- because the
device is defined
as a "no longer reliable" surgical instrument. Reliability is determined based
on a number of
factors. One factor can be wear ¨ after a certain number of uses, the parts of
the device can
become worn and tolerances between parts exceeded. For instance, the smart
battery 301 can
sense the number of button pushes received by the handle assembly 302 and can
determine when
a maximum number of button pushes has been met or exceeded. The smart battery
301 can also
monitor an impedance of the button mechanism which can change, for instance,
if the handle gets
contaminated, for example, with saline.
[00284] This wear can lead to an unacceptable failure during a procedure. In
some exemplary
embodiments, the smart battery 301 can recognize which parts are combined
together in a device
and even how many uses each part has experienced. For instance, looking at
FIG. 57, if the
battery assembly 301 is a smart battery according to the invention, it can
identify both the handle
assembly 302, as well as the particular TAG assembly 303, well before the user
attempts use of
the composite device. The memory 5706 within the smart battery 301 can, for
example, record
each time the TAG assembly 303 is operated. If each TAG assembly 303 has an
individual
identifier, the smart battery 301 can keep track of each TAG assembly's use
and refuse to supply
power to that TAG assembly 303 once the handle assembly 302 or the TAG
assembly 303
exceeds its maximum number of uses. The TAG assembly 303, the handle assembly
302, or
other components can include a memory chip that records this information as
well. In this way,
any number of smart batteries 301 can be used with any number of TAG
assemblies, staplers,
vessel sealers, etc. and still be able to determine the total number of uses,
or the total time of use
(through use of the clock 330), or the total number of actuations, etc. of
each TAG assembly,
each stapler, each vessel sealer, etc. or charge or discharge cycles.
[00285] In some exemplary embodiments, the smart battery 301 can communicate
to the user
through audio and/or visual feedback. For example, the smart battery 301 can
cause the LEDs
906 to light in a pre-set way. In such a case, even though the microcontroller
1006 in the
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CA 02750482 2011-08-25
generator 904 controls the LEDs 906, the microcontroller 1006 receives
instructions to be carried
out directly from the smart battery 301.
[00286] In yet a further exemplary embodiment, the microcontroller 1006 in the
generator
904, when not in use for a predetermined period of time, goes into a sleep
mode.
Advantageously, when in the sleep mode, the clock speed of the microcontroller
1006 is reduced,
cutting the current drain significantly. Some current continues to be
consumed, because the
processor continues pinging waiting to sense an input.
Advantageously, when the
microcontroller 1006 is in this power saving sleep mode, the microcontroller
1106 and the
battery controller 703 can directly control the LEDs 906. This is a power-
saving feature that
eliminates the need for waking up the microcontroller 1006. Another exemplary
embodiment
slows down one or more of the microcontrollers to conserve power when not in
use. For
example, the clock frequencies of both microcontrollers can be reduced to save
power. To
maintain synchronized operation, the microcontrollers coordinate the changing
of their respective
clock frequencies to occur at about the same time, both the reduction and,
then, the subsequent
increase in frequency when full speed operation is required. For example, when
entering the idle
mode, the clock frequencies are decreased and, when exiting the idle mode, the
frequencies are
increased.
[00287] In an additional exemplary embodiment, the smart battery 301 is able
to determine the
amount of usable power left within its cells 701 and is programmed to only
operate the surgical
device to which it is attached if it determines there is enough battery power
remaining to
predictably operate the device throughout the anticipated procedure. For
example, the smart
battery 301 is able to remain in a non-operational state if there is not
enough power with the cells
701 to operate the surgical device for 20 seconds. According to one exemplary
embodiment, the
smart battery 301 determines the amount of power remaining within the cells
701 at the end of its
most recent preceding function, e.g., a surgical cutting. In this embodiment,
therefore, the battery
assembly 301 would not allow a subsequent function to be carried out if, for
example, during that
procedure, it determines that the cells 701 have insufficient power.
Alternatively, if the smart
battery 301 determines that there is sufficient power for a subsequent
procedure and goes below
that threshold during the procedure, it would not interrupt the ongoing
procedure and, instead,
will allow it to finish and thereafter prevent additional procedures from
occurring.
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[00288] The following explains an advantage of the invention with regard to
maximizing use
of the device with the smart battery 301 of the invention. Take an example
where a set of
different devices have different waveguides. By definition, each of the
waveguides could have a
respective maximum allowable power limit where exceeding that power limit
overstresses the
waveguide and eventually causes it to fracture. One waveguide from the set of
waveguides will
naturally have the smallest maximum power tolerance. Because prior-art
batteries lack
intelligent battery power management, the output of prior-art batteries must
be limited by a value
of the smallest maximum allowable power input for the smallest/thinnest/most-
frail waveguide in
the set that is envisioned to be used with the device/battery. This would be
true even though
larger, thicker waveguides could later be attached to that handle and, by
definition, allow a
greater force to be applied. This limitation is also true for maximum battery
power. For
example, if one battery is designed to be used in multiple devices, its
maximum output power
will be limited to the lowest maximum power rating of any of the devices in
which it is to be
used. With such a configuration, one or more devices or device configurations
would not be able
to maximize use of the battery because the battery does not know the
particular device's specific
limits.
[00289] In contrast thereto, exemplary embodiments of the present invention
utilizing the
smart battery 301 are able to intelligently circumvent the above-mentioned
prior art ultrasonic
device limitations. The smart battery 301 can produce one output for one
device or a particular
device configuration and the same battery assembly 301 can later produce a
different output for a
second device or device configuration. This universal smart battery surgical
system lends itself
well to the modern operating room where space and time are at a premium. By
having a single
smart battery pack operate many different devices, the nurses can easily
manage the storage,
retrieval, and inventory of these packs. Advantageously, the smart battery
system according to
the invention requires only one type of charging station, thus increasing ease
and efficiency of
use and decreasing cost of surgical room charging equipment.
[00290] In addition, other devices, such as an electric stapler, may have a
completely different
power requirement than that of the ultrasonic surgical cautery assembly 300.
With the present
invention, a single smart battery 301 can be used with any one of an entire
series of surgical
devices and can be made to tailor its own power output to the particular
device in which it is
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CA 02750482 2011-08-25
installed. In one exemplary embodiment, this power tailoring is performed by
controlling the
duty cycle of a switched mode power supply, such as buck, buck-boost, boost,
or other
configuration, integral with or otherwise coupled to and controlled by the
smart battery 301. In
other exemplary embodiments, the smart battery 301 can dynamically change its
power output
during device operation. For instance, in vessel sealing devices, power
management is very
important. In these devices, large constant current values are needed. The
total power output
needs to be adjusted dynamically because, as the tissue is sealed, its
impedance changes.
Embodiments of the present invention provide the smart battery 301 with a
variable maximum
current limit. The current limit can vary from one application (or device) to
another, based on
the requirements of the application or device.
[00291] XII. HANDLE ASSEMBLY--MECHANICAL
[00292] FIG. 45 illustrates an exemplary embodiment of a right-hand side of
the handle portion
302 with the left shell half removed. The handle assembly 302 has four basic
functions: (1)
couple the battery assembly 301 to the multi-lead handle terminal assembly
3502; (2) couple the
TAG assembly 303 to a TAG attachment dock 4502; (3) couple the ultrasonic
cutting blade and
waveguide assembly 304 to a waveguide attachment dock 4504; and (4) provide
the triggering
mechanics 4506 to operate the three components (battery assembly 301, TAG
assembly 303, and
ultrasonic cutting blade and waveguide assembly 304).
[00293] a. TAG Attachment Dock
[00294] The TAG attachment dock 4502 is exposed to the environment and shaped
to
interchangeably secure the TAG assembly 303 to the handle assembly 302. The
waveguide
attachment dock 4504 is shaped to align a proximal end of the waveguide 1502
to the transducer
902. When the transducer 902 is docked in the TAG attachment dock 4502 and the
waveguide
assembly 304 is docked in the waveguide attachment dock 4504, and the
transducer 902 and
waveguide 1502 are attached together, the waveguide 1502 and the transducer
902 are held at the
handle assembly 302 in a freely rotatable manner.
[00295] As can be seen in FIGS. 45 and 46, the handle assembly 302 includes
two clamshell-
connecting body halves, the right half 4503 being shown in FIG. 45 and the
left half being shown
CA 02750482 2011-08-25
in FIG. 46. The two halves 4503, 4603 form at least a portion of the waveguide
attachment dock
4504, which can be considered as being exposed to the environment when the
waveguide rotation
spindle 3704 is not present. A first couple 4602 is operable to selectively
removably secure the
ultrasonic waveguide assembly 304 to the handle assembly 302. In the exemplary
embodiment
shown, the spindle 3704 has an intermediate annular groove 4603 shaped to
receive an annular
boss 4605. When the two halves 4503, 4603 are connected, the groove 4603 and
boss 4605 form
a longitudinal connection of the waveguide assembly 304 that is free to
rotate.
[00296] The TAG attachment dock 4502 opposes the waveguide attachment dock
4504. The
TAG attachment dock 4502 is exposed to the environment and has a second couple
4604
operable to removably secure the ultrasonic transducer 902 to the ultrasonic
waveguide 1502
when the ultrasonic waveguide assembly 304 is coupled to the waveguide
attachment dock 4504.
The couples 4602 and 4604 can simply be aligned passageways or any other
structure that place
the waveguide 1502 into axial alignment with the transducer 902. Of course,
the couples 4602
and 4604 can provide more structure, such as threads, that actually hold the
waveguide 1502
and/or transducer 902 to the handle or to one another.
[00297] b. Controls
[00298] Looking now to FIG. 46, a trigger 4606 and a button 4608 are shown as
components of
the handle assembly 302. The trigger 4606 activates the end effector 118,
which has a
cooperative association with the blade portion 116 of the waveguide 114 to
enable various kinds
of contact between the end effector 118 and blade portion 116 with tissue
and/or other
substances. As shown in FIG. 1, the end effector 118 is usually a pivoting jaw
(see e.g., FIGS.
73 et seq.) that acts to grasp or clamp onto tissue disposed between the jaw
and the blade 116.
[00299] The button 4608, when depressed, places the ultrasonic surgical
assembly 300 into an
ultrasonic operating mode, which causes ultrasonic motion at the waveguide
1502. In a first
exemplary embodiment, depression of the button 4608 causes electrical contacts
within a switch
4702, shown in FIG. 47, to close, thereby completing a circuit between the
battery assembly 301
and the TAG assembly 303 so that electrical power is applied to the transducer
902. In another
exemplary embodiment, depression of the button 4608 closes electrical contacts
to the battery
assembly 301. Of course, the description of closing electrical contacts in a
circuit is, here,
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CA 02750482 2011-08-25
merely an exemplary general description of switch operation. There are many
alternative
embodiments that can include opening contacts or processor-controlled power
delivery that
receives information from the switch 4702 and directs a corresponding circuit
reaction based on
the information.
[00300] FIG. 47 shows the switch 4702 from a left-side elevational view and
FIG. 48 provides a
cutaway perspective view of the interior of the handle body, revealing
different detail of the
switch 4800. In a first embodiment, the switch 4800 is provided with a
plurality of contacts
4804a-n. Depression of a plunger 4802 of the switch 4702 activates the switch
and initiates a
switch state change and a corresponding change of position or contact between
two or more of
the plurality of contacts 4804a-n. If a circuit is connected through the
switch 4702, i.e., the
switch 4702 controls power delivery to the transducer 902, the state change
will either complete
or break the circuit, depending on the operation mode of the switch 4702.
[00301] FIG. 49 shows an embodiment of the switch 4702 that provides two
switching stages.
The switch 4702 includes two sub-switches 4902 and 4904. The sub-switches 4902
and 4904
advantageously provide two levels of switching within a single button 4802.
When the user
depresses the plunger 4802 inward to a first extent, the first sub-switch 4902
is activated, thereby
providing a first switch output on the contacts 4804a-n (not shown in this
view). When the
plunger 4802 is depressed further inward to a second extent, the second sub-
switch 4904 is
activated, resulting in a different output on the contacts 4804a-n. An example
of this two-stage
switch 4702 in actual use would be for the TAG generator 904 to have two
possible output power
levels available, each resulting in a different motion displacement value of
the waveguide 1502.
Activation of the first sub-switch 4902 can, for example, initiate the first
output power level from
the generator 904 and activation of the second sub-switch 4904 could result in
a second power
level to be output from the generator 904. An exemplary embodiment of this two
stage switch
4702 provides a low-power level for the first displacement and a high-power
level for the second
displacement. Configuring the sub-switches 4902 and 4904 in a stack, shown in
FIG. 49,
advantageously makes it easy and intuitive for an operator to move from the
first switch mode,
i.e., first power level, to the second switch mode, i.e., second power level,
by simply squeezing
the plunger 4802 of the button 4702 with increased force.
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CA 02750482 2011-08-25
[00302] In one embodiment of the sub-switches 4902 and 4904, spring force
could be utilized,
with each spring having a different spring-force rating. When the plunger 4802
is initially
depressed, the first spring in the first sub-switch 4902 begins to compress.
Because a second
spring located in the second sub-switch 4904 is stiffer than the first spring,
only the first sub-
switch 4902 is caused to change switching states. Once the first sub-switch
4902 is depressed a
sufficient distance to change switching states, further (greater) force
applied to the plunger 4802
causes the second stiffer spring to depress and the second sub-switch 4904 to
change states.
[00303] In practice, ultrasonic cutting devices, such as ones employing the
present invention,
encounter a variety of tissue types and sizes and are used in a variety of
surgical procedure types,
varying from precise movements that must be tightly controlled to non-delicate
cutting material
that requires less control. It is therefore advantageous to provide at least
two ultrasonic cutting
power levels that allow an operator to select between a low-power cutting mode
and a higher-
power cutting mode. For example, in the low-power cutting mode, i.e., only the
first sub-switch
4902 is depressed, the tip of the waveguide 1502 moves at about 0.002 inches
of displacement.
In the higher-power cutting mode, i.e., both the first and second sub-switches
4902 and 4904 are
depressed, the tip of the waveguide 1502 moves at about 0.003 inches of
displacement, providing
a more robust cutting tool that can move through tissue at a quicker rate or
cut though tougher,
denser matter quicker than the lower-power setting. For example, cutting
through mesentery is
generally performed at a more rapid rate at higher power, whereas vessel
sealing can be
performed at lower power and over a longer period of time.
[00304] The present invention, however, is in no way limited to stacked
switches and can also
include switches that are independent of one another. For instance, the shape
of the button 4608
may have a first portion that makes contact with a first low-power switch and
a second portion
that, upon further movement of the button, makes contact with a second high-
power switch. The
present invention is to be considered as including any multiple-stage switch
that engages
different stages by movement of a single button.
[00305] In one exemplary embodiment of the present invention, the switch 4702,
4800 provides
a physical resistance analogous to a compound bow. Compound bows, which are
well known for
shooting arrows at a high rate of speed, have a draw-force curve which rises
to a peak force and
then lets off to a lower holding force. By recreating this physical affect
with the second sub-
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CA 02750482 2011-08-25
switch 4904, the user of the device will find moving into and engaging the
first sub-switch 4902
to be rather easy, while moving into the higher-power mode, initiated by
depression of the second
sub-switch 4904 requiring a higher depression force, to be an occurrence that
takes place only by
the operator consciously applying an increased force. Once the higher
depression force is
overcome, however, the force required to maintain the second sub-switch 4904
in the depressed
position decreases, allowing the operator to remain in the higher-power mode,
i.e., keeping the
button depressed, without fatiguing the operator's finger. This compound-bow-
type effect can be
accomplished in a variety of ways. Examples include an offset cam, overcoming
a pin force or
other blocking object, software control, dome switches, and many others.
[00306] In one exemplary embodiment of the present invention, the switch 4702
produces an
audible sound when the switch 4702 moves from the first mode to the second
higher-power
mode. For example, the audible sound can be emanated from button, itself, or
from the buzzer
802. The sound notifies the operator of entry into the higher-power mode. The
notification can
advantageously prevent unintended operation of the inventive ultrasonic
device.
[00307] c. Near-Over-Center Trigger
[00308] Referring now to FIGS. 61-64, a variable-pressure trigger will be
shown and described.
The components of the variable pressure trigger can be seen in the perspective
partial view of the
right hand side of the handle assembly 302 illustrated in each of FIGS. 61-64.
In this view,
several of the internal components are exposed and viewable because much of
the shell of the
handle assembly 302 is not present. In practice, many of the components shown
in FIGS. 61-64
are covered by the shell, protected, and not viewable.
[00309] Looking first to FIG. 61, at least a portion of a trigger pivot
assembly 6102 is shown.
The assembly 6102 includes a first pivoting member 6104 and a second pivoting
member 6106.
In the following discussion, a comparison between FIG. 61 and each of FIGS. 62-
64 will be
described that illustrates the interaction between the first pivoting member
6104 and the second
pivoting member 6106 as the trigger 4606 is progressively squeezed by an
operator.
[00310] The first pivoting member 6104 is an elongated structure and has a
first end 6112 and a
second end 6114. The first end 6112 of the first pivoting member 6104 is
rotationally coupled to
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CA 02750482 2011-08-25
a first pivot pin 6116 while the second end 6114 is rotationally coupled to a
second pivot pin
6118. In the elevational view of FIG. 61, the exemplary embodiment of the
first pivoting
member 6104 can be seen as including two separate halves, each half coupled to
the first pivot
pin 6116 and the second pivot pin 6118 and being connected together at a
center section. There
is, however, no requirement that this pivoting member comprise this
configuration. The pivoting
member can be any structure that couples the two pivot pins 6116 and 6118 and
provides the
proximally directed force at the first pivot pin 6116 to translate the
actuator for the end effector
118, which end effector 118 will be described in further detail below. As can
be seen in FIGS.
61 to 64, the first pivot pin 6116 rides within a longitudinally extending
guide track 6130 shown
on left body half 4603 of the handle assembly 302, a mirror image of which is
similarly present
on the opposing right body half 4503. As the trigger 4606 is depressed, shown
in the progression
of FIG. 61, to FIG. 62, to FIG. 63, to FIG. 64, the first pivot pin 6116
translates in the proximal
direction a sufficient distance to actuate the end effector 118 from an at-
rest position (shown by
the first pivot pin position in FIG. 61) to a fully actuated position (shown
by the first pivot pin
position in FIG. 64).
[00311] In accordance with the exemplary embodiment shown, the second pivot
pin 6118 is
coupled to and is part of the trigger 4606. In particular, the entire second
pivoting member 6106,
including the pivot pin 6118, actually comprises a furthest extent of the
trigger 4606. This
furthest extent of the trigger 4606 (the second pivoting member 6106) is,
itself, rotationally
coupled to a third (fixed) pivot pin 6110 within the handle assembly 302. This
third pivot pin
6110 defines the axis about which the trigger 4606 rotates with respect to the
handle assembly
302. The third pivot pin 6110 is shared by a sliding rotational-lockout member
6508, which
works in conjunction with a rotational lockout blade. The purpose and details
of the rotational
lockout blade will be explained in the following section.
[00312] Because the position of the third pivot pin 6110 is fixed with respect
to the handle
assembly 302, when the trigger 4606 is squeezed by the operator, the first
pivot pin 6116 moves
away from the third pivot pin 6110. In addition, as the first pivot pin 6116
is moving away from
the third pivot pin 6110, the second pivot pin 6118 traverses an arc starting
at the position shown
in FIG. 61, where the second pivot pin 6118 is well below an imaginary line
6120 connecting the
first pivot pin 6116 to the third pivot pin 6110, to the position shown in
FIG. 64, where the
CA 02750482 2011-08-25
second pivot pin 6118 is much closer to that imaginary line 6120 still
connecting the first pivot
pin 6116 to the third pivot pin 6110.
[00313] The movement of the trigger 4606 from the position shown in FIG. 61,
through the
positions shown in FIGS. 62 through 64 results in a clamping movement of the
end effector 118
in a direction toward the waveguide 1502. In other words, squeezing the
trigger 4606 causes the
end effector 118 to move from an open position to a closed position (via
movement of the outer
tube 7302 as described below). Advantageously, interaction between the first
pivoting member
6104 and the second pivoting member 6106, illustrated in a comparison of FIGS.
61 through 64,
provides a trigger motion with varying requisite pressures to maintain trigger
depression. This
variable pressure linkage (6110, 6106, 6118, 6104, 6116) advantageously
reduces fatigue on the
operator's hand because, once fully depressed, it requires much less pressure
to keep the trigger
4606 in the depressed position as compared to the pressure required to
partially depress the
trigger 4606 as shown, for example, in FIG. 62.
[00314] More specifically, when an operator first applies pressure to the
trigger 4606, a first
force is required to move the second pivot pin 6118 (with reference to the
orientation shown in
FIG. 61) upwards. The force required to actuate the end effector 118 is
actually longitudinal
because the first pivot pin 6116 must move proximally. This force moves the
second pivot pin
6118 along an arc that, consequently, moves the first pivot pin 6116 away from
the third pivot
pin 6110 and defines two force vectors along the pivoting members 6104, 6106.
The two force
vectors, in the position shown in FIG. 61, are at an angle 6122 of
approximately 100 and are
indicated with a left-pointing black vector and a right-pointing white vector
for clarity.
[00315] Turning now to FIG. 62, it can be seen that the trigger 4606 has been
moved from the
resting position shown in FIG. 61. This partial movement occurs when the
trigger is squeezed
during a typical medical procedure at first tissue contact. As the trigger
4606 is squeezed, i.e.,
moved toward the handle assembly 302, the first pivot pin 6116, the first
pivoting member 6104,
the second pivoting member 6106, and the second pivot pin 6118 all change
positions. More
specifically, the second pivoting member 6106 rotates about the third pivot
pin 6110, which is
fixed in its position. Because the third pivot pin 6110 is fixed, the second
pivot pin 6118 begins
to swing upward, i.e., toward the imaginary line 6120. As the second pivot pin
6118 swings
upward, a force is applied to the first pivot member 6104, which translates
along the first pivot
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member 6104 and is applied to the first pivot pin 6116. In response, the first
pivot pin 6116
slides proximally in a direction away from the waveguide assembly 304. In this
first stage of
translation, shown in FIG. 62, the angle of the force vectors 6122 can be seen
as having increased
from that shown in FIG. 61.
[00316] In FIG. 63, the trigger 4606 is closed even further. As a result,
further movement of the
first pivoting member 6104, the second pivoting member 6106, the first pivot
pin 6116, and the
second pivot pin 6118 occurs. As this movement takes place, the second pivot
pin 6118 moves
even closer to the imaginary line 6120, i.e., closer to being collinear with
the first 6116 and third
6110 pivot pins. As indicated by the force vectors 6122, the forces applied to
the pivoting
member's 6104, 6106 begin to significantly oppose each other. The exemplary
angle between the
vectors 6122 is, in this position, approximately 150 .
[00317] Finally, in FIG. 64 the trigger 4606 has been squeezed until it makes
contact with the
battery assembly holding portion of the handle assembly 302. This is the point
of maximum
translation of the first pivoting member 6104, second pivoting member 6106,
and the first
pivoting pin 6116. Here, the force vectors substantially opposite one another,
thereby reducing
the amount of force felt at the trigger 4606. That is, as is known in the
field of mechanics,
maximum force is required when two vector forces are additive, i.e., point in
the same direction,
and minimum force is required when two vector forces are subtractive, i.e.,
point in opposite
directions. Because, in the orientation shown in FIG. 64, the vectors become
more subtractive
than additive, it becomes very easy for the user to keep the trigger 4606
depressed as compared to
the position shown in FIG. 61. The ultimate closed position shown in FIG. 64
is referred to
herein as a "near-over-centered" position or as "near over centering." When
the trigger 4606 is
in the near-over-centered position, the force required to keep the trigger
depressed is
approximately 45% or less than the force required to initially squeeze the
trigger away from the
position shown in FIG. 61.
[00318] d. Rotational Lock-Out
[00319] The present invention provides yet another inventive feature that
prevents rotation of
the waveguide assembly 304 whenever ultrasonic motion is applied to the
waveguide 1502. This
rotational lockout feature provides enhanced safety by preventing the cutting
blade from
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unintentional rotational movement during a surgical procedure. In addition,
prevention of
rotation ensures a solid electrical connection is maintained throughout
operation of the device
300. More specifically, the pair of contacts 5402, 5404 do not have to slide
along the contact
rings 5406, 5408 because a fixed electrical connection at one location along
the contact rings
5406, 5408 is maintained during operation. The rotational lockout, according
to one exemplary
embodiment of the present invention, is accomplished through use of a
rotational lockout
member 6508 shown in FIGS. 65 and 66.
[00320] Referring first to FIG. 65, a perspective close-up view of the right
hand side of handle
assembly 302 is shown with the right-side cover removed. In this view, a
rotational lockout
member 6508 can be seen positioned adjacent a rotation-prevention wheel 6502
(which is
rotationally fixed to the waveguide rotation spindle 3704 and, thereby, to the
waveguide
assembly 304). The waveguide assembly 304 is, therefore, able to rotate along
its longitudinal
axis only if the rotation-prevention wheel 6502 is unencumbered and also able
to rotate upon that
longitudinal axis.
[00321] To prevent revolution of the rotation-prevention wheel 6502, the
rotational lockout
member 6508 includes a wheel-engagement blade 6504 that extends therefrom in a
direction
toward the rotation-prevention wheel 6502. In the position shown in FIG. 65,
the rotational
lockout member 6508 does not interfere with the rotation prevention wheel 6502
because the
wheel-engagement blade 6504 is at a distance from the outer circumference
thereof. In such an
orientation of the blade 6504, the rotation-prevention wheel 6502, as well as
the waveguide
assembly 304, can freely spin upon the longitudinal axis of the waveguide
assembly 304.
[00322] Referring now to FIG. 66, the rotational lockout member 6508 has been
displaced into a
rotation blocking position. In this position, the wheel-engagement blade 6504
enters the space
between two adjacent castellations 6602 on the outer circumference of the
rotation-prevention
wheel 6502 and engages the side surfaces of the castellations 6602 if the
rotation-prevention
wheel 6502 rotates. The rotational lockout member 6508 is fixed in its
position within the
handle assembly 302 and, because of this connection, the engagement between
the wheel-
engagement blade 6504 and the rotation-prevention wheel 6502 entirely prevent
the rotation-
prevention wheel 6502 from rotate about the longitudinal axis of the waveguide
assembly 304.
For example, with 72 castellations 6602 on the outer circumference, the
rotation-prevention
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wheel 6502 has substantially no rotational play when rotationally locked.
FIGS. 67 through 69
show that the wheel-engagement blade 6504 engages the rotation-prevention
wheel 6502 only
when the button 4608 is depressed, thereby preventing substantially all
rotational movement of
the waveguide assembly 304 when ultrasonic movement of the waveguide 1502
occurs.
[00323] FIG. 67 shows a perspective underside view of the rotational lockout
member 6508
within the handle assembly 302. Once again, the right-hand cover of the handle
assembly 302 is
removed, thereby exposing several of the internal mechanical components of the
handle assembly
302. These components include the button 4608, shown here in a transparent
view, a U-shaped
member 6702 that slidably engages with the rotational lockout member 6508, and
a spring 6704
that biases the U-shaped member 6702 away from a bottom portion of the
rotational lockout
member 6508. FIG. 67 shows the rotational lockout member 6508, the U-shaped
member 6702,
and the spring 6704. In the position shown in FIG. 67, the spring 6704 is
preloaded by pressure
that is asserted by the U-shaped member 6702. The rotational lockout member
6508 is
rotationally coupled to and pivots about a pivot pin 6706, which is fixedly
coupled to the handle
assembly 302.
[00324] In addition, FIG. 67 shows a torsional spring 6708 that biases the
rotational lockout
member 6508 away from the castellations 6602 of the rotation-prevention wheel
6502. The
torsional spring 6708 ensures that the natural resting position of the
rotational lockout member
6508 is disengaged from the rotation-prevention wheel 6502. A spring force of
the torsional
spring 6708 is selected so that it is less than a spring force of the spring
6704. Therefore,
movement of the rotational lockout member 6508 can occur prior to the spring
6704 being fully
compressed.
[00325] In operation of the rotation prevention system, when the button 4608
is depressed after
a short distance, a rear side of the button 4608 physically contacts the U-
shaped member 6702
and moves the U-shaped member 6702 as further proximal button movement occurs.
In other
words, when depressed, the button 4608 imparts a proximal force on the U-
shaped member 6702
in a direction against the biasing force of the spring 6704. This proximal
force causes the spring
6704 to compress and allows the U-shaped member 6702 to move in a direction
toward the
rotational lockout member 6508. This movement is shown in FIG. 68, where the U-
shaped
member 6702 is closer to the rotational lockout member 6508 than the position
shown in FIG.
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67. In the view of FIG. 68, the spring 6704 is no longer visible because the U-
shaped member
6702 has moved proximate to the rotational lockout member 6508 to a point that
the lockout
member 6508 completely obscures the spring 6704 in this view.
[00326] When the button 4608 is further depressed, as shown in FIG. 69, the
rotational lockout
member 6508 pivots around the pivot pin 6706 and swings upwardly toward the
rotation-
prevention wheel 6502. As this upward swing occurs, the wheel-engagement blade
6504
engages the castellations 6602 of the rotation-prevention wheel 6502. In other
words, the
position of the rotational lockout member 6508 shown in FIG. 69 corresponds to
the position of
the rotational lockout member 6508 shown in FIG. 66. Similarly, the position
of the rotational
lockout member 6508 shown in FIG. 67 corresponds to the position of the
rotational lockout
member 6508 shown in FIG. 65.
[00327] In some circumstances, when the button 4608 is depressed, the wheel-
engagement blade
6504 lands on one of the castellations 6602 and does not fall between two of
the castellations
6602. To account for this occurrence, a stroke distance, i.e., the distance
the U-shaped member
6702 is able to move towards the rotational lockout member 6508 allows an
electrical activation
of the device without requiring actual physical movement of the rotational
lockout member 6508.
That is, the rotational lockout member 6508 may move slightly, but does not
need to fit between
two of the castellations 6602 for ultrasonic operation to occur. Of course,
rotation is still
prevented, as any rotational movement will cause the rotational lockout member
6508 to move
up and into the castellations 6602.
[00328] In a further exemplary embodiment of the present invention, a
rotational lockout
member 7002, as shown in FIGS. 70 and 71, can be provided with one or more
blades 7004,
7006 that engage with an outer surface 7008 of a rotation-prevention wheel
7001. In this
particular embodiment, the rotation-prevention wheel 7001 does not have teeth
on its outer
circumference, as the embodiment of the rotation-prevention wheel 6502 of
FIGS. 65 to 69. In
the embodiment of FIGS. 70 and 71, the outer surface 7008 of the rotation-
prevention wheel
7001 is sufficiently malleable to allow the blades 7004, 7006 to engage the
outer surface 7008,
for example, to actually cut into the outer circumference of the rotation
prevention wheel 7001.
However, in certain embodiments, where a razor-type blades 7004, 7006 are
utilized, the
CA 02750482 2011-08-25
rotation-prevention wheel 7001 is sufficiently hard to prevent the blades
7004, 7006 from
penetrating more than a predefined depth when an expected amount of force is
applied.
[00329] Once the blades 7004, 7006 are driven into the outer surface 7008 of
the rotation-
prevention wheel 7001, as is shown in FIG. 71, the rotation-prevention wheel
7001 is rendered
unable to rotate about the longitudinal axis of the waveguide assembly 304. Of
course, a single
blade or three or more blades can be used to prevent the rotation-prevention
wheel 7001 from
rotating. By separating and angling the blades 7004 and 7006 from one another,
rotation
prevention is enhanced in either rotational direction. In other words, when
the blades 7004 and
7006 are angled away from one another, rotation of the rotation-prevention
wheel 7001, in either
direction, causes one of the blades 7004 or 7006 to dig deeper into the
rotation-prevention wheel
7001. In addition, in this particular embodiment of the rotational-lockout
member 7002, a
portion of the rotation-lockout member 7002 may capture the third pivot pin
6110.
[00330] XIII. TAG -- MECHANICAL
[00331] Referring to FIG. 50, the reusable TAG assembly 303 is shown separate
from the
handle assembly 302. The inventive TAG assembly 303 includes a transducer
shaft 5002 with an
ultrasonic waveguide couple 5004 that is configured to attach a waveguide
securely thereto and,
upon activation of the transducer shaft 5002, to excite the attached
waveguide, i.e., impart
ultrasonic waves along the length of the waveguide.
[00332] In this exemplary embodiment, the waveguide couple 5004 is female and
includes
interior threads, which are used to secure the TAG assembly 303 to the
waveguide 1502 (see,
e.g., FIG. 45) by screwing an end of the waveguide 1502 onto the threads of
the waveguide
couple 5004 with a predefined amount of torque. The torque should be
sufficient so that a
mechanical connection created by the torque is not broken during normal
operation of the device.
At the same time, the torque applied to couple the threads should not exceed a
force that will
cause the threads to become stripped or otherwise damaged. During initial
coupling of the
transducer 902 and waveguide 1502, all that is needed is that one of the
transducer 902 and
waveguide 1502 remains relatively stationary with respect to the other. The
waveguide rotation
spindle 3704 is rotationally fixedly coupled to the transducer 902, which,
together, are
rotationally freely connected to the body 5005 of the TAG assembly 303. As
such, the
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CA 02750482 2011-08-25
waveguide rotation spindle 3704 and the transducer 902 are both able to freely
rotate with respect
to the body 5005. To make the waveguide-transducer connection, therefore, the
waveguide 1502
can be held stationary as the waveguide rotation spindle 3704 is rotated to
couple the interior
threads of the transducer shaft 5002 with the corresponding male threads at
the proximal end of
the waveguide 1502. Preferably, the waveguide 1502 is coupled, i.e., screwed
onto the threads of
the waveguide couple 5004 to a point where the mechanical connection is
sufficient to transfer
the mechanical ultrasonic movement from the TAG assembly 303 to the waveguide
1502.
[00333] In one exemplary embodiment of the present invention, a torque wrench
(see FIG. 88)
couples to the waveguide rotation spindle 3704 and allows the user to rotate
the spindle 3704 to a
predetermined amount of torque. Once the rotational coupling pressure between
the waveguide
couple 5004 and the waveguide 1502 exceeds a predetermined amount of torque,
the outer
portion of the torque wrench slips about an inner portion and, thereby, the
spindle 3704 and no
further rotation of the spindle 3704 takes place. Through use of the torque
wrench, an operator is
able to apply precisely the proper amount of tension to the junction between
the TAG assembly
303 in the waveguide 1502 and is also prevented from damaging the threads on
either the
waveguide couple 5004 or on the waveguide 1502. This embodiment of the torque
wrench also
clips onto the spindle 3704 to prevent any possibility of the wrench slipping
off of the TAG
assembly 303 without outside force acting upon it.
[00334] The TAG assembly 303 also has a housing 5006 that protects and seals
the internal
working components (shown in FIG. 53) from the environment, as shown by FIGS.
50 and 53.
Because the TAG assembly 303 will be in the sterile field of the operating
environment, it is
sterilizable, advantageously, by vapor phase hydrogen peroxide, for example.
As such, the seal
between the housing 5006 and the body 5005 is aseptic and/or hermetic.
[00335] According to one exemplary, non-illustrated embodiment of the present
invention, the
transducer 902 is located entirely inside the housing 5006 __________________
where it cannot be readily secured
by the operator, for example, by holding it steady by hand when the waveguide
assembly 304 is
being secured. In such an embodiment, the TAG assembly 303 is provided with a
transducer
rotation lock. For example, the transducer rotation lock can be a button that
slides into a recess
in the housing 5006 or, alternatively, by fixing the rotation of the
transducer 902 at a maximum
rotational angle so that, once the maximum rotation is reached, for example,
360 degrees of
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CA 02750482 2011-08-25
rotation, no additional rotation is possible and the waveguide assembly 304
can be screwed
thereon. Of course, a maximum rotation in the opposite direction will allow
the waveguide
assembly 304 to be removed as well.
[00336] The housing 5006 has a securing connection 5012 shaped to selectively
removably
secure to a corresponding connector part of the handle assembly 302. See,
e.g., FIG. 56. The
connection 5012 can be any coupling connection that allows the TAG assembly
303 to be
removably attached and secured to the handle assembly 302, such as the
exemplary "dove-tail"
design shown in FIGS. 50 to 53 and 56. The area of contact between the handle
assembly 302
and the TAG assembly 303 can be sealed so that, in the event of surgical
fluids contacting the
TAG assembly 303, they will not introduce themselves into the interior of the
TAG attachment
dock 4502.
[00337] It is advantageous for the TAG assembly 303 to be selectively
removable from the
handle assembly 302. As a separate component, the TAG assembly 303 can be
medically
disinfected or sterilized (e.g., STERRADCD, V-PRO , autoclave) and reused for
multiple
surgeries, while the less-expensive handle assembly 302 itself may be
disposable. In addition,
the TAG assembly 303 can be used in multiple handles or in the same handle up
to a desired
maximum number of times before it is required to be disposed.
[00338] FIGS. 51 and 52 provide two additional perspective views of the TAG
assembly 303.
FIG. 52 shows a display window for a user display system (for example, the RGB
LED(s) 906)
on external surface of the housing 5006 of the TAG assembly 303. As explained
above, the RGB
LED 906 provides various signaling to the user indicating conditions and modes
of the surgical
assembly 300.
[00339] FIG. 53 provides a top view of the TAG assembly 303 with the housing
5006 removed,
thereby exposing the generator circuitry of the TAG assembly 303, see, e.g.,
FIG. 9. In a further
exemplary embodiment, the generator circuitry includes a memory electrically
connected at least
to the processor of the TAG assembly 303 or to the processor in the battery
assembly 301. The
memory can be used, for instance, to store a record of each time the TAG
assembly 303 is used.
Other data relevant to the TAG assembly 303 and/or the waveguide assembly 304
and/or the
housing assembly 302 and/or the battery assembly 301 can be stored as well for
later access and
83
CA 02750482 2011-08-25
analysis. This record can be useful for assessing the end of any part of the
device's useful or
permitted life, in particular, the TAG assembly 303 itself For instance, once
the TAG assembly
is used twenty (20) times, the TAG assembly 303 or the battery assembly 301
can be
programmed to not allow a particular handle or battery to function with that
"old" TAG assembly
(e.g., because the TAG assembly 303 is, then, a "no longer reliable" surgical
instrument). The
memory can also store a number of uses any of the device's peripherals. For an
illustrative
example only, after a certain number of uses, it is possibly that one of the
parts of the device can
be considered worn as tolerances between parts could be considered as
exceeded. This wear
could lead to an unacceptable failure during a procedure. In some exemplary
embodiments, the
memory stores a record of the parts that have been combined with the device
and how many uses
each part has experienced.
[00340] In some exemplary embodiments, a memory exists at the battery assembly
301 and the
handle assembly 302 is provided with a device identifier that is
communicatively coupled at least
to the battery assembly 301 and is operable to communicate to the smart
battery 301 at least one
piece of information about the ultrasonic surgical assembly 300, such as the
use history discussed
in the preceding paragraph, a surgical handle identifier, a history of
previous use, and/or a
waveguide identifier. In this way, a single smart battery assembly 301 can
record use
information on a number of different handle and TAG assemblies 302, 303. When
the battery
assembly 301 is placed into a charging unit, such a memory can be accessed and
the data about
each part of the system 301, 302/304, 303 can be downloaded into the charger
and, if desired,
transmitted to a central facility that is communicatively coupled (e.g.,
through the Web) to the
charging station.
[00341] FIG. 54 shows one example of how the generator 904 and the transducer
902 are
electrically coupled so that a physical rotation of the transducer 902 with
respect to the generator
904 is possible. In this example, the generator 904 has a pair of contacts
5402, 5404 protruding
from its underside, adjacent the transducer 902. Proximity of the transducer
902 to the generator
904 places one of the pair of contacts 5402, 5404 in physical communication
with a
corresponding pair of contact rings 5406, 5408 on the transducer's body 5410
so that a driving
signal can be steadily and reliably applied to the transducer 902 when needed.
Advantageously,
the pair of contacts 5402, 5404 maintains electrical contact regardless of the
angle of rotation of
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CA 02750482 2011-08-25
the transducer 902. Therefore, in this embodiment, the transducer 902 can
rotate without any
limitation as to the maximum angle or number of rotations. Additionally, the
rings 5406, 5408
and contacts 5402, 5404 ensure that the transducer 902 remains in electrical
contact with the
generator circuitry regardless of the point of rotation at which the torque
wrench stops the
tightening the transducer 902 to the waveguide 1502.
[00342] As shown in FIG. 37, the surgical handle assembly 302 has a spindle
3704 attached to
the waveguide assembly 304. The spindle 3704 has indentions that allow a
surgeon to easily
rotate the spindle 3704 with one or more fingers and, therefore, to
correspondingly rotate the
attached waveguide assembly 304 and the transducer 902 connected to the
waveguide 1502.
Such a configuration is useful for obtaining a desired cutting-blade angle
during surgery.
[00343] FIG. 55 shows one exemplary embodiment of the TAG assembly 303 where
the body
5005 and the transducer's shell have been removed. When a voltage is applied
to the
piezoelectric crystal stack 1504, the shaft 5002 moves longitudinally within
and relative to the
housing 5006. In this embodiment, the waveguide coupler 5004 is female and
includes internal
threads (not visible in this view), which are used to secure the transducer
assembly 303 to the
non-illustrated waveguide 1502 by screwing the waveguide 1502 into the threads
with an
appropriate amount of torque.
[00344] A novel feature of the TAG assembly 303 is its ability to mechanically
and electrically
connect at the same time. FIG. 56 shows an exemplary embodiment of the TAG
assembly 303 in
the process of docking with the handle assembly 302. At the same time the
transducer 902 is
being coupled to a waveguide 1502 (attached to the handle assembly 302), the
TAG assembly's
electrical connector 5010 is brought into contact with the handle assembly's
electrical connector
5602. The coupling of the TAG's electrical connector 5010 with the handle's
electrical
connector 5602 places the piezoelectric crystal stack 1504 in electrical
communication (direct or
indirect) with the battery assembly 301 docked with the handle assembly 302,
as shown in FIG.
37 for example. This substantially simultaneous coupling can be configured to
occur in all
embodiments of the present invention.
[00345] In accordance with further exemplary embodiments of the present
invention, the TAG
assembly 303 provides a mechanical connection prior to establishing an
electrical connection.
CA 02750482 2011-08-25
That is, when attaching the TAG assembly 303 to the handle 302, a mechanical
connection is
established between the waveguide 1502 and the ultrasonic waveguide couple
5004 prior to an
electrical connection being made between the TAG assembly's electrical
connector 5010 and the
handle assembly's TAG electrical connector 5602. Advantageously, because an
electrical
connection is not made until after the mechanical connection is established,
electrical "bouncing"
is avoided in this embodiment. More specifically, as the threads 8604 of the
waveguide 1502
couple to the ultrasonic waveguide couple 5004, the electrical connection
being made after a
solid mechanical connection insures that the TAG assembly's electrical
connector 5010 and the
handle assembly's TAG electrical connector 5602 are in a fixed positional
relationship, at least
momentarily, and instantaneous removal and reestablishment of the electrical
connection will not
take place. Similarly, when the assembly 300 is being disassembled, the
electrical connection is
broken prior to a full separation of the mechanical connection.
[00346] In accordance with other exemplary embodiments of the present
invention, the
ultrasonic surgical device 300 is able to accept and drive a plurality of
waveguide types, i.e.,
having varying dimensions. Where the handheld ultrasonic surgical cautery
assembly 300 is able
to accept and drive waveguides 1502 of varying types/dimensions, the handheld
ultrasonic
surgical cautery assembly 300 is provided with a waveguide detector coupled to
the generator
904 and operable to detect the type (i.e., the dimensions or characteristics)
of the waveguide 1502
attached to the transducer 902 and to cause the generator 904 to vary the
driving-wave frequency
and/or the driving-wave power based upon the detected waveguide type. The
waveguide detector
can be any device, set of components, software, electrical connections, or
other that is/are able to
identify at least one property of a waveguide 1502 connected to the handheld
ultrasonic surgical
cautery assembly 300.
[00347] XIV. WAVEGUIDE ASSEMBLY
[00348] FIGS. 73 to 87 provide detailed illustrations of exemplary embodiments
of the
waveguide assembly 304. The waveguide assembly 304 receives ultrasonic
movement directly
from the transducer 902 when the waveguide 1502 is physically coupled to the
TAG assembly
303. The blade portion 7304 of the waveguide 1502 transfers this ultrasonic
energy to tissue
being treated. The ultrasonically-moving blade portion 7304 facilitates
efficient cutting of
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organic tissue and accelerates blood vessel clotting in the area of the cut,
i.e., accelerated
coagulation through cauterization.
[00349] Referring to FIG. 73, a perspective partial view of the distal end
7306 of the waveguide
assembly 304 is shown. The waveguide assembly 304 includes an outer tube 7302
surrounding a
portion of the waveguide 1502. A blade portion 7304 of the waveguide 1502
protrudes from the
distal end 7306 of the outer tube 7302. It is this blade portion 7304 that
contacts the tissue
during a medical procedure and transfers its ultrasonic energy to the tissue.
The waveguide
assembly 304 also includes a jaw member 7308 that is coupled to both the outer
tube 7302 and
an inner tube (not visible in this view). As will be explained below, the
outer tube 7302 and the
non-illustrated inner tube slide longitudinally with respect to each other. As
the relative
movement between the outer tube 7302 and the non-illustrated inner tube
occurs, the jaw 7308
pivots upon a pivot point 7310, thereby causing the jaw 7308 to open and
close. When closed,
the jaw 7308 imparts a pinching force on tissue located between the jaw 7308
and the blade
portion 7304, insuring positive and efficient blade-to-tissue contact.
[00350] FIG. 74 provides a perspective underside view of the distal end 7306
of the waveguide
assembly 304 shown in FIG. 73 with the outer tube 7302 removed. In this view,
a distal end
7306 of the inner tube 7402 can be seen coupled to the jaw 7308. This coupling
is provided by,
in the exemplary embodiment illustrated in FIG. 74, a union of a pair of
bosses 7408 on the jaw
7308 with boss-engaging openings 7414 in each of the pair of arms 7418, 7420
that capture the
bosses 7408 when the jaw 7308 is inserted therebetween. This relationship is
better shown in the
cross-sectional perspective underside view of FIG. 75. From this view, it can
be seen that the
boss-engaging openings 7414 of the arms 7418, 7420 of the inner tube 7402 are
coined 7502.
The coined arms 7418, 7420 provide a solid connection between the inner tube
7402 and the jaw
7308. By coining the openings 7414, the inner tube 7402 is able to engage the
bosses 7408 on
the jaw 7308 without having to rely on the outer tube 7302 for structural
pressure/support.
[00351] FIG. 75 also shows that the waveguide 1502 is separate from, i.e., not
attached to, the
jaw 7308 or inner tube 7402. In other words, the waveguide 1502, when
energized with
ultrasonic energy, will move relative to the inner tube 7402 and jaw 7308 but
will not contact the
inner tube 7402 and will only contact the jaw 7308 if the latter is pivoted
against the blade
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CA 02750482 2011-08-25
portion 7304 without the presence of tissue therebetween. Features of the
present invention that
facilitate this independent movement of the waveguide 1502 will be described
below.
[00352] Returning to FIG. 74, the jaw 7308 is provided with a pair of flanges
7422, 7424 at a
proximal end 7426 thereof. The flanges 7422, 7424 extend and surround the
waveguide 1502 on
opposing sides thereof. Each one of the flanges 7422, 7424 has, at its end, a
pivot control tab
7411, 7412, respectively, extending below the waveguide 1502 when the bosses
7408 of the jaw
7308 are secured within the boss-engaging openings 7414 in the arms 7418,
7420. It is not a
requirement for the pivot control tabs 7411, 7412 to extend below the
waveguide 1502 as shown
in FIG. 74; this configuration exists in the exemplary embodiment shown.
[00353] Returning briefly back to FIG. 73, the elevational end view of the
waveguide assembly
304 shows that the pivot control tabs 7411, 7412 of the flanges 7422, 7424 of
the jaw 7308
engage a pair of openings 7311, 7312 in a distal portion 7306 of the outer
tube 7302. These
features are better illustrated in the fragmentary, cross-sectional side view
of FIG. 77.
[00354] Because the view of FIG. 77 is a cross-sectional view, only one 7424
of the two flanges
7422, 7424 is shown and the surface shown is an inside surface of the flange
7424.
Correspondingly, only one of the pivot control tabs 7412 is shown, as well as
a single one of the
pair of openings 7312 in the distal portion 7306 of the outer tube 7302. This
view makes clear
that the opening 7312 surrounds and captures the pivot control tab 7412.
Therefore, if the outer
tube 7302 is moved toward the jaw 7308, the opening 7312 will also move
relative to the jaw
7308. Conversely, if the outer tube 7302 is moved away from the jaw 7308, the
opening 7312
will also move relative to the jaw 7308 in the opposite direction. The
captured pivot control tab
7412 nested within the opening 7312 causes a corresponding rotational movement
of the jaw
7308 around the pivot point 7310.
[00355] FIG. 78 provides an elevational partial side view of the end effector
of the waveguide
assembly 304. This view shows the outer tube 7302 substantially covering the
flange 7422 of the
jaw 7308, leaving only the pivot control tab 7411 extending from the opening
7311. It should
now be apparent that, when the outer tube 7302 is slid in a proximal direction
7702, i.e., in a
direction away from the jaw 7308, the outer tube 7302 will pull the pivot
control tabs 7411, 7412
in the proximal direction 7702. This action causes the jaw 7308 to pivot
around the pivot point
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CA 02750482 2011-08-25
7310 clockwise in FIG. 78 to close, i.e., clamp toward the blade portion 7304
of the waveguide
1502. This closed position of the jaw 7308 is shown in FIG. 79.
[00356] FIG. 80 provides another view of the distal end of the jaw 7308 in a
closed position
where the jaw 7308 is placed in contact with the blade portion 7304 of the
waveguide 1502.
Again, this relationship between the jaw 7308 and the blade portion 7304 of
the waveguide 1502
is the result of a proximal translation of the outer tube 7302 with respect to
the inner tube 7402.
The jaw member 7308, together with the inner and outer tubes 7302, 7402 and
the blade portion
7304 of the waveguide 1052, can be referred to as an end effector. The end
effector can trap
tissue between an interior of the jaw member 7308 and an opposing surface of
the blade portion
7304. Trapping the tissue in this way advantageously places the tissue in
solid physical contact
with the waveguide 1502. In this way, when the waveguide 1502 moves
ultrasonically, the
movement of the waveguide is directly transferred to the tissue, causing a
cut, a cauterization, or
both.
[00357] To facilitate this translation, and with reference back to FIG. 74,
one or more corsets
7404 are provided on the inner tube 7402. The corset 7404 is an area of the
inner tube 7402
having a smaller diameter D' than the average outer diameter D of the inner
tube 7402. See FIG.
74. In accordance with an exemplary embodiment of the present invention, the
corset 7404 is/are
provided at a node(s) of the ultrasonic waveguide 1502. In other words, the
corsets 7404 are
located at points along the waveguide 1502 where the waveguide 1502 does not
exhibit
ultrasonic motion. Therefore, the decreased diameter of the inner tube 7402
and its physical
coupling to an interior surface of the outer tube 7302 does not adversely
affect the waveguide's
ability to resonate at an ultrasonic frequency. As also illustrated in FIGS.
74 and 75, for
example, a seal 7406 resides within the corset 7404. The seal 7406, according
to one exemplary
embodiment, is an elastomeric 0-ring type seal. Of course, many other
materials may be selected
as well. The seal 7406 has an outer diameter sufficiently larger than the
outer diameter D of the
7402 so that the sealing effect is maintained but to not prevent the outer
tube 7302 and the inner
tube 7402 from translating with respect to one another without substantial
friction when the jaw
7308 is actuated.
[00358] As is also shown in FIGS. 74 and 75, a thickness of the seal 7406 is
smaller than a
longitudinal length of the corset 7404 in which the seal 7406 resides. This
difference in
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CA 02750482 2011-08-25
dimension allows the seal 7406 to travel along the longitudinal length of
saddle 7426 when
shaped, as shown, as an annulus having a substantially circular cross-section.
In particular, this
traveling feature of the seal 7406 takes place when the outer tube 7302 is
translated with respect
to the inner tube 7402. Even more specifically, the seal 7406 is dimensioned,
i.e., has an annular
height, to bridge a gap between an inner surface of the outer tube 7302 and
the saddle 7426 of the
inner tube 7402 as shown in FIGS. 75 and 77. By filling this gap completely,
the seal 7406 at the
distal end 7306 of the waveguide assembly 304 prevents intrusion of moisture
or other
contaminants within the region between the outer tube 7302 and the inner tube
7402. As the
outer tube 7302 is translated, the tight fit between the outer tube 7302, the
inner tube 7402, and
the seal 7406 causes the seal 7406 to roll or slide within the saddle 7426
while, at all times
maintaining a water-tight seal between the outer tube 7302 and the inner tube
7402. This
translation T is illustrated, for example, with the thick arrows in FIG. 77.
[00359] Referring now to FIG. 81, the distal end of the waveguide assembly 304
at the saddle
7426 is shown in cross-section. This view shows the outer tube 7302
surrounding the inner tube
7402 and the seal 7406 disposed therebetween in the saddle 7426 of the corset
7404. As
explained, the deformable seal 7406 is a water-tight connection between the
inner wall 8102 of
the outer tube 7302 and the outer surface of the saddle 7426 to prevent
moisture or other
contaminants from passing from a distal side 8108 of the seal 7406 to a
proximal side 8110 of
the seal 7406.
[00360] FIG. 81 also shows a cross-section a coupling spool 8104. The coupling
spool 8104
encircles a distal portion of the waveguide 1502 and is disposed at
substantially the same
longitudinal location as the corset 7404. As stated above, the corset 7404 is
located at or
substantially near an ultrasonic-movement node of the waveguide 1502.
Therefore, the coupling
spool 8104 is also located at or substantially near that node of the waveguide
1502 and, likewise,
does not couple with the waveguide 1502 to receive ultrasonic movement. The
coupling spool
8104 provides a support structure that physically links the waveguide 1502 to
an inside surface
8106 of the corset 7404. In the cross-sectional view of FIG. 81, the coupling
spool 8104 has a
barbell-shaped longitudinal cross-section. This reduced cross-section of
elastomeric material
reduces the amount of deflection of the waveguide when clamped. The thick
cross-section of the
CA 02750482 2011-08-25
barbell ends of the seal maintain a water tight seal when the middle section
deflects during
clamping.
[00361] FIG. 82 provides a perspective view of an embodiment of the coupling
spool 8104. In
this view, an interior surface 8202 of the coupling spool 8104 can be seen.
This interior surface
8202 is in direct physical contact with the waveguide 1502 when the waveguide
assembly 304 is
assembled, as shown in FIG. 81, for example. The perspective view of FIG. 82
also reveals an
exterior saddle shape 8204 of the coupling spool 8104 that substantially
corresponds to the
interior shape of the saddle 7426, which is illustrated in FIG. 81 too.
[00362] To help capture and retain the tissue between the jaw member 7308 and
the waveguide
1502, the jaw member 7308 includes an insert 7314 having a plurality of teeth
7316. This insert
7314 provides the jaw member 7308 with an ability to grip the tissue. An
exemplary
embodiment of the insert 7314 is shown in the perspective views of FIG. 84
(from a distal-most
end of the insert 7314) and FIG. 85 (from a proximal-most end of the insert
7314). In addition to
the plurality of teeth 7316, the insert 7314 includes a distal-most surface
8402, a central smooth
channel 8404 located between first 7316a and second 7316b longitudinal rows of
the plurality of
teeth 7316 on a lower surface 8403, a flat proximal clamping surface 8405, and
an upper flange
8406 for securing the insert 7314 to the jaw member 7308. The distal-most
surface 8402 is, as
can be seen in FIG. 73, an exposed blunt front surface of the distal end of
the waveguide
assembly 304. FIG. 73 illustrates a channel 7318 of the jaw member 7308 in
which the insert
7314 is disposed when assembled. The inner surfaces of the channel 7318
substantially
correspond to the outer surfaces of the upper flange 8406 so that the insert
7314 may be retained
in the jaw member 7308 in a substantially movement-free manner. In the
exemplary
embodiment of the channel 7318 illustrated, the distal end of the channel 7318
is narrower than
the intermediate portion so that the insert 7318 may slide from a proximal end
of the jaw member
7308 up to but not past the distal end of the channel 7318. Also shown in the
exemplary
embodiment of FIG. 85 is a retaining tab 8502 that, when the insert 7314 is
placed in the jaw
7308 all the way distally, can be bent downward (towards the insert 7314) and
below the top
plane of the insert 7314. In such a bent configuration, the distal end of the
retaining tab 8502
will oppose, and possibly rest against, the rear surface 8504 of the insert
7314 and/or flange
8406. With such an opposition, the insert 7314 is prevented from exiting the
jaw 7308.
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CA 02750482 2011-08-25
[00363] The offset between the proximal-most surface 8402 and the flange 8406,
shown in FIG.
84, facilitates the placement of proximal-most surface 8402 at the distal most
portion of the jaw
member 7308. That is, the insert 7314 slides within the jaw member 7308 until
it is fully seated
within the jaw member 7308. It is, however, the flange 8406 that is physically
secured by the
jaw member 7308. More specifically, as is shown in FIGS. 84 and 85, the flange
8406 extends
beyond the plurality of teeth 7316 on both sides thereof However, the flange
8406 does not
extend all the way to the proximal-most surface 8402. When the insert 7314 is
slid inside the
jaw member 7308, the extending side portions of the flange 8402 travel within
the channel 7318
formed in the jaw member 7308. Because the flange 8406 does not extend all the
way to the
proximal-most surface 8402, when the flange 8406 reaches the end of the
channel 7318, the
proximal-most surface 8402 of the insert 7314 will extend beyond the channel
7318 up to the
position shown in FIG. 73.
[00364] Focusing now on the exemplary embodiment of the teeth 7316, it can be
seen in FIGS.
84 and 85 that the teeth 7316 do not extend completely across the lower
surface 8408 of the
insert 7314. Instead, in the embodiment of FIGS. 84 and 85, a first row of
teeth 7316a and a
second row of teeth 7316b, which oppose the first row of teeth 7316a, are
separated by a central
smooth channel 8404. The central smooth channel 8404 provides a solid smooth
surface that
lines up directly over the waveguide 1502. It is this smooth surface 8404 that
comes into contact
with the ultrasonically-moving waveguide 1502 during a procedure and helps
seal the tissue by
facilitating continued, non-impeded ultrasonic movement of the waveguide 1502
with even
pressure along its length.
[00365] Moving now to FIG. 86, a fragmentary perspective view of an interior
of the handle
portion 302 is illustrated. This view shows a proximal-most end 8601 of the
waveguide 1502,
which features a set of threads 8604 used to couple the waveguide 1502 to the
TAG assembly
303. As described above, the illustrated location of the proximal-most end
8601 of the
waveguide 1502 within the handle portion 302 is substantially the location
where the waveguide
assembly 304 remains when it is coupled to the TAG assembly 303. When the TAG
assembly
303 is inserted into the handle portion 302, see, for example FIG. 45, the
transducer shaft 5002
aligns with and thereby allows a secure longitudinal coupling of the threads
8604 and the
ultrasonic waveguide couple 5004.
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CA 02750482 2011-08-25
[00366] The waveguide 1502 is surrounded by the inner tube 7402 and, then, the
outer tube
7302. This view of the proximal-most end 8606 of the outer tube 7302 shows
that the outer tube
7302 terminates at its proximal-most end 8606 with a flared section 8608. The
flared section
8608 features a pair of channels 8610 and 8612 (8612 not fully shown in this
view) forming a
keyway. These channels are shown as opposing but need not be in this
configuration. Residing
within the channels 8610, 8612 is a yoke 8602 that is fixedly coupled to the
waveguide 1502.
The coupling of the yoke 8602 and the waveguide 1502 will be shown in more
detail in the
following figure, FIG. 87. Continuing with FIG. 86, it can be seen that the
yoke 8602 is provided
with a boss 8616 that extends within the channel 8610. Although not shown in
this view, the
yoke 8602 is also provided with a second boss that extends likewise within the
second channel
8612. Engagement between the bosses 8616 of the yoke 8602 and the channels
8610, 8612 of
the flared section 8608 provides a rotational-locking relationship between the
waveguide 1502,
the inner 7402, and the outer tube 7302. That is, because the bosses engage
the channels 8610,
8612, any rotation of the waveguide 1502 is shared by both the inner tube 7402
and the outer
tube 7302. The proximal end of the inner tube 7402 does not extend past the
yoke 8602. The
rotational connection between the yoke 8602 and the inner tube 7402 occurs
through an internal
feature of the waveguide rotation spindle 3704.
[00367] Focusing now on FIG. 87, a perspective view of an interior of the
handle portion 302 is
once again illustrated. In this view, however, the outer tube 7302 has been
removed (along with
a right half of the waveguide rotation spindle 3704). The removed outer tube
7302 exposes a
majority of the yoke 8602. Although not viewable in either FIG. 86 or FIG. 87,
the yoke 8602 is,
in one exemplary embodiment of the present invention, symmetrical with a
second boss
extending in a direction substantially directly opposite the first boss 8616.
As the perspective
view of FIG. 87 shows, the waveguide 1502 features at least one exterior
spline 8702, here a set
of splines symmetrically disposed about the waveguide 1502. Each spline 8702
extends away
radially from a central longitudinal axis 8706 of the waveguide 1502. The yoke
8602 is provided
with a plurality of interior keyways 8704, each keyway 8704 aligning with one
of the extensions
of the spline 8702 and having a shape substantially corresponding to a
respective one of the
splines 8702 so that, when connected as shown, the yoke 8602 securely rests at
its shown
longitudinal position on the waveguide 1502. This longitudinal position on the
waveguide 1502,
too, is located at an ultrasonic vibration node where movement is minimal/non-
existent. This
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CA 02750482 2011-08-25
aligning and securing engagement between the keyways 8704 and the splines 8702
places the
keyways 8704 and the splines 8702 in a fixed rotational relationship. In other
words, as the
waveguide 1502 rotates, so too must the yoke 8602.
[00368] Referring back now to FIG. 66, it can now be seen that the channels
8610, 8612 of the
flared section 8608 of the outer tube 7302 are the features that engages the
rotation-prevention
wheel 6502. Due to this engagement, any rotation imparted on the waveguide
rotation spindle
3704 by the user will result in a direct and corresponding rotation of the
rotation-prevention
wheel 6502, the outer tube 7302, the inner tube 7402, the yoke 8602, and the
waveguide 1502.
The following is a result of this connection configuration: when the
rotational lockout number
6508 is engaged with the rotation-prevention wheel 6502, not only is the
rotation-prevention
wheel 6502 prevented from rotating, so too is the entire waveguide assembly
304, 3704, 7302,
7402, 8602, 1502. In the same sense, when the rotation-prevention wheel 6502
is not engaged
with the rotational lockout number 6508, a user can freely rotate the spindle
3704, which is
physically coupled to the rotation-prevention wheel 6502, and cause a rotation
of the waveguide
assembly 304 along a longitudinal axis 8706.
[00369] XV. ADDITIONAL SAFETY FEATURES
[00370] In an exemplary safety embodiment for any of the configurations of the
invention, the
system can have a safety mechanism grounding the surgeon using the device to
the handheld
ultrasonic surgical cautery assembly 300. In the event the waveguide 1502
accidentally makes
contact with the surgeon, the handheld ultrasonic surgical cautery assembly
300 senses this
grounding and immediately ceases movement of the waveguide 1502, thereby
instantly
preventing the surgeon from cutting him/herself. It is possible to provide a
safety circuit that can
sense contact with the surgeon and interrupt ultrasonic power delivery because
the hand-held
instrument 300 is not connected to earth ground. For example, a capacitive
contact patch located
on the handle assembly 302 is connected to a capacitive-touch sensing circuit
(such as is used for
capacitive switching and known to those in the art) and disposed to detect
contact of the working
tip with the surgeon. When such contact is detected, the drive circuit 904 of
the instrument will
be shut down to avoid applying cutting energy to the surgeon. Such a sensing
circuit would be
impractical in systems of the prior art, where the handpiece is connected to a
large piece of earth-
grounded electrical equipment.
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CA 02750482 2011-08-25
[00371] In accordance with another exemplary embodiment of the present
invention, after the
battery assembly 301 is physically and electrically coupled to the handle
assembly 302, the
handheld ultrasonic surgical cautery assembly 300 will not operate until the
button 4608 is
changed from a depressed state to a released state, i.e., actively placed into
a non-depressed
position. This feature prevents the handheld ultrasonic surgical cautery
assembly 300 from
operating immediately upon connection of the battery assembly 301 to the
handle assembly 302,
which otherwise could occur if the operator was unintentionally depressing the
button 4608 when
connecting the battery assembly 301 to the handle assembly 302.
[00372] As has been described, the present invention provides a small and
efficient hand-held
ultrasonic cutting device that is self-powered and, therefore, cordless, which
eliminates entirely
the expensive set-top box required by the prior art devices. Advantageously,
the device of the
invention allows a user to operate completely free of cords or other tethering
devices. In addition
to the advantages of reduced cost, reduced size, elimination of a tethering
cord for supplying
power and carrying signals, and providing a constant motional voltage, the
instant invention
provides unique advantages for maintaining the sterile condition in a surgical
environment. As
has been explained, the inventive device is comprised entirely of sterilizable
components that are
maintained wholly in a sterile field. In addition, all electronic controls of
the inventive system
exist within the sterile field. Therefore, any and all troubleshooting can
take place inside the
sterile field. That is, because the inventive device is not tethered to a
desktop box, as required in
the prior art, a user need never exit the sterile field to perform any
function with the inventive
handheld ultrasonic surgical cautery assembly 300 (e.g., troubleshooting,
replacing batteries,
replacing waveguide assemblies, etc.). Furthermore, the inventive two-stage
button allows an
operator complete control of any surgical task without requiring the operator
to focus their visual
attention on the instrument itself. In other words, the operator does not have
to look to ensure
(s)he is preparing to push the proper button, as only one button is used.
[00373] The invention also provides low-voltage or battery-voltage switching
or wave-forming
stages prior to the transformer voltage step-up stage. By "marrying" all of
the frequency
sensitive components within one place (i.e., the handle), the present
invention eliminates any
inductive losses that occur between prior art set-top boxes and hand pieces ¨
a disadvantage
suffered by all prior-art ultrasonic cautery/cutting devices. Because of the
close coupling
CA 02750482 2015-04-08
between the drive circuitry and the matching network 1012, the overall power
modification
circuit is tolerant of higher Q factors and larger frequency ranges.
[00374] The scope of the claims should not be limited by the preferred
embodiments set
forth in the examples, but should be given the broadest interpretation
consistent with the
description as a whole.
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