Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02582811 2007-04-04
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DESCRIPTION
Apparatus and Method for Surgical Fastening
Field of the Invention
~ This is a division of Canadian Application Serial No.: 2,336,873, filed
June 29, 1999.
Field of the Invention
The present invention relates generally to surgical fastening tools for
i~- fixating tissue and/or surgical materials during minimally invasive
surgery, and
particularly to a surgical fastening tool having a space-efficient, simplified
fastening niechanism that permits deployment of the tool through a minimal
opening but which also maximizes the gripping area of the applied surgical
fastener. More particulariy, the invention relates to a reduced diameter (5mm)
I~ surgical fastening tool for use in hernia repair. The tool is deployed
through a
reduced diameter access port in the body to fasten a piece of surgical mesh to
body tissue using a specially formed fastener having a maximized gripping
area. The tool also has a simplified, jam-free fastening mechanism. The
present invention also relates to methods for repairing a patient's hernia
through a minimized diameter access port while maximizing the gripping area
of the surgical fastener as well as methods for applying surgical fasteners
from
a miniatured device with reduced risk of jamming.
Background of the Invention
During some surgical procedures, most notably hernia repair
procedures, it is considered desirable by many practitioners to reinforce the
muscle tear or other defect with a piece of surgically implantable mesh.
Physicians most often use an open-weave, sintered mesh made of
polypropylene and hold it in place by a type of permanent fixation method. One
common method of fixation uses metallic fasteners, such as staples, which
remain in the body permanently after the hernia repair. Medical device
designers have created a number of larger-size devices to
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fasten tissue and/or surgical materials to tissue during
minimally invasive surgery. According to these designs, the
devices typically contemplate a 10-mm or wider application
tool used to deploy a fastener. For example, Green et al.,
U.S. Patent No. 5,356,064, col. 21, 11. 34-53, describes a
device for deployment through a 12 mm trocar guide tube
wherein the device stacks a set of staples at roughly a
forty-five degree angle to the axis of the device to provide
greater visibility. See Green et al. Fig. 18.
However, these tools are being judged too large for
deployment according to the current minimally invasive
techniques which are bringing the size of the surgical
instruments and access ports down to a 5mm diameter.
Moreover, Green et al. cannot be readily scaled down because
of physical limitations caused by the generally transverse
stacking of fasteners. See Green et al., Fig. 18. In
addition, the design of Green et al. cannot be effectively
scaled down because the fastener discharged by the
application tool must be of sufficient scale to securely
span across the defect and/or strands of surgical mesh and
efficaciously engage sufficient tissue area for adequate
gripping strength. Green et al. employs a fastener forming
system which unduly reduces the finished span or width of
the fastener relative to its initial width. See Green et
al., Fig. 20-21, col. 22, 11. 38-48. Thus, reduction in
Green et al.'s tool diameter would result in an
unsatisfactory gripping area for the finished fastener.
In addition to reducing fastener-gripping strength,
smaller diameter tools have other problems. For example,
miniaturization of the surgical fastening tool increases the
likelihood of jamming, a common problem for minimally
invasive surgical fastener tools, because the critical
tolerances for the device's moving parts would be reduced
along with the size of the instrument. Accordingly, slight
changes in deployment stress and temperature can effect the
mobility of the moving tool parts. The Origin Tacker,
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though of 5 mm diameter, employs a rotational actuation mechanism to
deploy a helical fastener. Rotation increases the complexity needed for the
actuation mechanism, and creates greater need to ensure reliable translation
of trigger action.
What is needed is a space-efficient surgical fastening tool that
minimizes its outer diameter while maximizing the gripping area and strength
of the fastener. the fastening mechanism of the desired surgical fastening
tool must not be complicated and should be limited to a few actuated parts to
reduce the probability of jamming during minimally invasive surgery. The
device should be designed to avoid double firing and incomplete firing. The
device should also permit for the easy reloading of additional fasteners
during extensive surgical procedures. The prior art devices are inadequate
to meet these objectives.
Summary of the Invention
The present invention relates to surgical fasteners, fastening tools
and methods for securing tissue and/or surgical materials during minimally
invasive surgery. In particular, the devices of the present invention are
adapted to minimize the diameter of the surgical fastening tool while
maximizing the area gripped by the fastener. Furthermore, the devices of
the present invention are adapted to discharge the fastener by way of a
simplified fastening mechanism with few actuated parts. The surgical
materials to be fastened may be surgical mesh, sutures, prostheses, linings
or the like. The tissue to be fastened may be tissue, foreign or endogenous
to the patient.
In accordance with an embodiment of the present invention there is
provided a fastening apparatus for use in endoscopic surgery, comprising:
a) a handle portion; b) a triggering mechanism; and c) a fastener applicator
having a pusher biased in a distal direction, a stack of fasteners engaged by
the pusher, a fastener positioning spring biasing a distalmost fastener toward
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a driving channel, a slide for engaging the distalmost fastener in the driving
channel, and an anvil having a single fastener-forming point.
Another embodiment of the present invention provides a fastening
apparatus for use in endoscopic surgery, comprising: a) a handle portion;
b) a triggering mechanism; and c) a fastener applicator having a pusher
biased in a distal direction, a stack of fasteners engaged by the pusher, a
fastener positioning spring biasing a distalmost fastener toward a driving
channel, a slide for engaging the distalmost fastener in the driving channel,
and an anvil having an essentially round-edged cross-section.
In one arrangement, the apparatus includes three major elements: a
fastener, a fastener applicator comprising a fastener magazine; a handle
portion to which the applicator is attached; and a triggering mechanism. The
triggering mechanism may be housed in either the fastener applicator, the
handle portion or in a combination of the two. In a first aspect of the
invention, the fastener applicator has a cantilevered anvil with a cross
section around which the fastener may be formed at a single focal point
when the fastener is pressed by a slide. The fastener may initially be M-
shaped, upside-down U-shaped or other suitable shape. The anvil may
have a cross section that is essentially triangular and a shaping slide with a
cooperating notch that is angled to closely receive the triangular cross-
section of the anvil. Fig. 1. The single-point anvil permits the width of the
slide which forms the fastener to be the same or less than the width of the
stored fastener but without sacrificing the finished span (installed width) of
the applied fastener and the area it encloses. An anvil with a semi-circular
or other round edged cross-section may also be used in combination with a
round-notched slide. The space-efficiency of the slide and anvil permits a
reduction in the overall width of the fastener applicator relative to the
width of
the fastener. Traditional staple type surgical fasteners have a slide which,
when of reduced width, unacceptably reduce the span of the applied
fastener to accommodate the "horns" of the slide. See Fig. 2.
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The apparatus may be of unitary, non-detachable design wherein a
5 fastener applicator, handle portion and a triggering mechanism are provided
in a single integral unit. The fasteners may be stored in the handle portion
of
the apparatus or loaded from outside the device just prior to use. According
to a second aspect, the applicator may function as a fastener magazine and
is readily removed from or locked onto the handle portion by virtue of a novel
mechanism for quick attachment and detachment. The applicator comprises
a slide actuator which operates a slide in response to operation of the
triggering mechanism to discharge fasteners. The novel mechanism locks
the slide actuator into a secure, locked position within the detached
applicator magazine so that the slide actuator is properly located to engage
the motion-translating parts of the triggering mechanism of the device when
attached. The novel mechanism then automatically frees the slide actuator
upon attachment of the applicator to the handle thereby making the device
ready for use. Specifically, the novel mechanism employs an "L-shaped" pin
with a recessed region that rotates into and out of engagement with the slide
actuator based on its interaction with pre-formed recesses in the handle of
the device during attachment and detachment. Thus, when the applicator
comprising a magazine of fasteners runs out of fasteners, the user may
substitute a second applicator containing a fresh magazine. This
construction also permits the handle portion to be sterilized and re-used.
The fastener applicator may either be of unitary construction or made
of several interconnecting pieces. However, in the preferred arrangement, a
tube of circular cross-section houses a magazine formed by the juxtaposition
of two cooperating half shells, known collectively as the insert, each half-
shell having essentially a semi-circular cross section. The two half-shells
are
preferably inserted into the tube during manufacture. When combined, the
two half-shells and the slide form the magazine or storage channel which
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contains a set of vertically stacked fasteners. The fastener applicator is
separable from the handle portion so that the handle portion may be
supplied with a new applicator containing a new set of fasteners once the
first set of fasteners has been used.
A third aspect also disclosed minimizes the possibility of jamming
caused by an improperly timed interplay between independently moving
parts and also reduces the probability of jamming due to the failure of the
trigger to actuate a key part of a multi-part actuation mechanism. Thus, in
the preferred arrangement of the device employing the third aspect, the
insert and slide form two channels: a fastener storage channel and a
fastener-driving channel. The fastener storage channel contains a plurality
of vertically stacked fasteners, stacked tips to back, thereby reducing
applicator width relative to tools which use transversely stacked fasteners.
The fasteners are continually urged toward the distal end of the applicator by
a pusher that is biased by a pusher spring. The fastener-driving channel
further houses a slide that rides in the driving channel to engage the back of
the first fastener positioned within the driving channel. According to the
most
preferred arrangement, movement of the slide drives the fastener onto the
anvil while the notch in the slide shapes the fastener over the anvil
according
to the first aspect.
The insert may additionally comprise a system of leaf springs that
assist in securely positioning and advancing the fasteners one at a time
during the repeated fastener application process. The action of the leaf
springs is controlled by slide location. Accordingly, in the most preferred
embodiment of the third aspect, the applicator contains one actuated part,
the slide, that is moved by the active application of force generated by the
triggering mechanism. The rest of the moving parts in the applicator are
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biased to move in a certain direction but are restrained or liberated based on
the location of the slide. According to this most preferred embodiment, with
the applicator held against the target, the slide is fully advanced distally
to
drive the first fastener's tips into the target and to shape the fastener on
the
anvil. When the slide is subsequently retracted after shaping the first
fastener, a pair of biased ejector springs are liberated and kick the formed
fastener off the end of the anvil, freeing the apparatus from the fastener.
Upon further retraction of the slide, a biased fastener positioning spring is
released and pushes the second fastener from the distal most position in the
storage channel into the driving channel. Meanwhile, a biased stop spring
restrains the third fastener from advancing in the storage channel until the
second fastener is being advanced in the driving channel. The third fastener
is then released by the depressed stop spring and advanced to the distal
most position in the storage channel. Fully actuating the slide to discharge
the second fastener and then fully retracting the slide positions the third
fastener in the driving channel. This process may be repeated until each of
the fasteners in the magazine has been applied.
In the interest of further reducing the potential for jamming of the
miniaturized tool during surgery, according to a fourth aspect of the
invention, the apparatus may employ a unique jam-free ratchet and pawl
mechanism, housed in the handle portion, that assures complete travel of
the slide in both directions during application of each fastener. This
embodiment of the apparatus comprises a plunger assembly that is linked to
the slide by means of the slide actuator. Complete forward and reverse
movement of the plunger assembly results in a complete corresponding
motion of the slide. In the preferred embodiment, the plunger assembly
reciprocates forward and backward within the body of the handle portion.
The body of the handle has a tapered slot, adjacent to the plunger assembly,
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which contains a pawl. The side of the plunger assembly that is immediately
adjacent to the tapered slot contains a series of grooves which collectively
form a ratchet extending for a distance approximately equal to the travel of
the plunger assembly. The length of the pawl is longer than the
perpendicular distance from the bottom of the tapered slot to the bottom of
the ratchet grooves, such that once the pawl is engaged in the ratchet
grooves, the pawl is oblique and prevents reversal of the plunger's direction
of travel.
When the pawl has moved past the end of the ratchet, a wire spring
urges the pawl to assume a position transverse to the direction of travel. As
the plunger assembly is moved back towards its original position, the pawl
again engages the ratchet but with opposite orientation. Accordingly, the
pawl again prevents reverse travel of the plunger assembly until the stroke is
fully completed and the pawl has cleared the length of the ratchet. The
spring then reorients the pawl transversely in preparation for the next
stroke.
In this way, the slide, which is connected to the plunger assembly by the
slide actuator, is prevented from reversing mid-stroke and safeguards
against jamming, non-firing and misfiring.
The methods disclosed relate to deploying a fastener with maximized
gripping area using a space-efficient deployment mechanism having few
actuated parts. In a preferred method, a hernia repair patient is incised and
fitted with a port to access the site of the hernia. After access to the site
of
the hernia is achieved, the hernia is reduced and the surgical mesh is placed
over the defect using minimally invasive techniques. The surgical fastening
tool apparatus is deployed through an access port and its tip pressed
against the mesh and the tissue to be fastened. The tool is then triggered by
means of the triggering mechanism. The fastener is then formed by the
action of the slide pressing the fastener onto the surface of the anvil. In
this
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manner, the mesh is secured to the body tissue by the gripping strength of
the fastener.
When employing the first aspect disclosed, the method generally
includes the following steps: forming a fastener by placing it over a single
focal point anvil; pressing the fastener against the single focal point anvil
using a slide having a width that is approximately the same as or less than
the width of the fastener; discharging the fastener into the tissue of the
patient.
In a method that employs the second aspect disclosed, the method of
fastener application is executed within a detachable applicator which may be
readily replaced with a second applicator containing additional fasteners
using a novel mechanism.
In a method that employs the third aspect disclosed, a fastener is
applied by the following preferred steps: the fastener is moved from the
storage channel where it has been vertically stacked to the driving channel
by the biased fastener positioning spring as the slide is retracted; the slide
is
then advanced until the slide engages the fastener in the driving channel
and drives the fastener over the anvil to form the fastener. During
advancement of the slide the biased stop spring is forced back into a recess
in the insert thereby allowing the next fastener to move forward in the
storage channel in response to the force of the biased pusher spring; the
slide is then retracted, freeing the biased ejector springs to kick the formed
fastener off the end of the anvil; finally, the slide is further retracted
until the
fastener positioning spring is once again free to move the distal-most
fastener from the storage channel into the driving channel.
The present invention was developed, in part, out of recognition of the
need for a reduced diameter fastening tool which could discharge, from a
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5 reduced diameter applicator, a fastener that firmly holds mesh and tissue
together. Unlike a traditional staple shape where the back of the staple lies
parallel to the tissue surface into which it is deployed, the present
disclosure
teaches that a U-form wire fastener applied in the form of a diamond relative
to the tissue surface has certain advantages including reduction in the size
10 of fastener needed to achieve high gripping strength. The installed span of
the fastener and the area captured by the fastener are two useful
parameters for evaluating the efficacy of a fastener. Figs. 3a and 3b on
Table 1 demonstrate the conventional finishing of a "U" shaped staple by
assuming an arbitrary initial width of 8mm (assuming negligible thickness of
the wire and bends of 90 degrees) and monitoring these two parameters.
The traditional "U"-shaped staple may have many finished shapes
depending on the width selected between bends in the back of the staple. In
essence, the width between bends determines the finished span of the
applied staple. See Fig. 3b. The length of the staple legs is arbitrary but
the
legs should not reach too deeply into the tissue to avoid damaging
underlying structures. On the other hand, the staple must reach deeply
enough to enclose sufficient tissue to develop adequate holding strength.
With reference to Fig. 3b and Table 1, it is clear that, as the finished
conventional staple span is stepwise decreased, the area of the projected
rectangle formed by the finished staple goes through a maximum value (8).
By comparison, the preferred diamond shaped fastener, described in Figs.
4b and Table 2, has a finished span of .707 x the initial width, W, and
encloses a projected area double the size of the maximum traditional design
(16). Moreover, the preferred diamond-shaped finished fastener shown in
Fig. 4b, maintains a span greater than all but the most extreme of possible
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finished shapes made by the conventional process (shapes which suffer
from greatly diminished gripping area). Although the user may choose other
initial widths as well as other bend angles for the traditional method, the
relative relationship between the gripping area of the diamond fastener
disclosed and the conventional finished fastener remain. When viewed in
light of the longer finished span permitted by the present invention, these
Figures and Tables demonstrate the superior geometry of the finished
fastener formed by the instant apparatus.
TABLE 1
CONVENTIONAL DESIGN
W-2L=SPAN
L x SPAN = AREA
W 2L SPAN AREA
8 2 6 6
8 3 5 7 1/2
8
4 4 8
8 5 3 7 1/2
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TABLE 2
FASTENER FORMED BY PREFERRED EMBODIMENT OF THE
INVENTION
V1
(W 2 ) _
( Span
) SPAN = 1
W = 0.707 W
2
AREA w
=
2
Thus, if W 8, SPAN = 5.66
AREA = 16
To the extent the finished angle of the inserted legs relative to the
surface plane of the tissue is related to the fastener's strength, a
fastener's
legs which finish parallel to the tissue surface are superior to those which
finish perpendicular to tissue. Accordingly, in an alternate embodiment,
described in Fig. 5a and 5b and Table 3, the fastener may be initially formed
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with an upwardly concave back of an arbitrary angle and with legs which are
initially parallel, approximating the capital letter "M". Fig. 5a. In the
embodiment shown, the angle of the concave back is greater than ninety-
degrees. During formation of the fastener the central bend is reversed to
allow the legs to finish more parallel to the tissue surface. Fig. 5b.
According to this embodiment, the length of the finished span remains
essentially the same as the finished span shown in Fig. 4a, 4b but the
projected area gripped by the fastener is reduced.
TABLE 3
SPAN >.707W
AREA = 'h (> W/2)2 > 8
To the extent finished span is chosen as the key parameter for
achieving holding strength, the preform shown in 5a may be formed over the
anvil by partial application of the slide such that the back of the fastener
becomes essentially flat, and parallel with the tissue surface into which the
fastener is being deployed. In this variation, the slide is not pushed all the
way down such that the back ends up more or less straight and the legs
angled. The span and area calculations then become those for the finished
shape.
The gripping area is reduced to a value that is still greater than or
equal to the maximum area gripped by the conventionally processed U-
shaped design described in Fig. 3b. Importantly, the finished span of the
conventionally processed U-shaped design is substantially less (.5W=4)
compared to the finished span of the concave back fastener (.707W=5.66).
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Thus, it is clear that with respect to the length of the finished span and the
gripping area of the fastener, triangular finished fastener designs, shown in
Fig. 5b, are also superior to conventionally processed designs. This
recognition is particularly important when the goal is to miniaturize a
surgical
fastening tool for use in minimally invasive surgery.
Miniaturization of a fastener tool places a premium on the gripping
efficiency of the fastener relative to the space available for its deployment
within the small diameter of the applicator. Assuming that the applicator of a
surgical fastening tool comprises a tubular housing, a slide that form the U-
shaped fastener with two bends in the back must have "horns" and be wider
than the finished span thereby wasting tool diameter.
Thus, as a practical matter, the conventional mechanism necessarily
results in a fastener with a smaller finished span for a given tool diameter.
See Fig. 2. In contrast, the finished diamond and triangular fasteners shown
in Figs. 1, 4b and 5b, do not need the slide to be wider than the finished
span of the fastener.
Using the fastener and anvil configurations of Figs. 4 and 5, the tool
design need not sacrifice the length of the finished span to accommodate
the fastener forming apparatus itself. Moreover, the disclosed invention
requires less force to deploy the fastener because only one bend is formed
during deployment rather than two bends as with the conventional design.
This reduction in force is a significant advantage for a miniaturized device
whose miniaturized parts are relatively weak and may fail under repeated
stress.
The present invention was also developed in part to solve other
problems associated with miniaturization of fastener devices, such as
jamming, non-firing and misfiring. Thus, the invention contemplates that the
deployment mechanism of the device has few mechanically actuated parts
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because the critical tolerances for such actuated parts are reduced in the
miniaturization process. Moreover, surgical fastening tools are at times
5 roughly handled in a hospital setting and may undergo significant abuse
during sterilization. This can cause the internal uncoupling of actuated parts
or other damage not visible from the surface of the tool, only to be
discovered during use of the device. Thus, a feature limiting the number of
actuated parts leads to a sturdier, more reliable device. This feature also
10 simplifies the manufacturing process.
Finally, the invention was motivated by the knowledge that
miniaturization of the surgical fastening tool may cause the tool to carry
fewer fasteners then may be needed for a particular surgical procedure.
Thus, according to another aspect of the invention, the fastening tool can
15 comprise an interchangeable fastener magazine.
25
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Brief Description Of The Drawings
Reference is made to a brief description of the
drawings, which are intended to illustrate surgical
fastening tools for use herein. The drawings and detailed
description which follow are intended to be merely
illustrative and are not intended to limit the scope of the
invention as set forth in the appended claims.
Fig. 1 is a schematic front view of an embodiment of
the preferred fastener, space-efficient shaping slide and
anvil of the present invention.
Fig. 2 is a schematic front view of a traditional
staple with its shape-forming slide about to form the staple
on a rectangular anvil.
Fig. 3a is a schematic front view of a traditional U-
shaped staple prior to application of a conventional shaping
slide.
Fig. 3b is a schematic front view of a finished
traditional U-shaped staple after application of a
conventional shaping slide.
Fig. 4a is a schematic front view of an embodiment of
the fastener of the present invention prior to application
of the shaping slide.
Fig. 4b is a schematic front view of an embodiment of
the fastener of the present invention after application of
an embodiment of the shaping slide of the present invention.
Fig. 5a is a schematic front view of alternate
embodiment of the fastener of the present invention prior to
application of an embodiment of the shaping slide of the
present invention.
Fig. 5b is a schematic front view of the alternate
embodiment of the fastener of the present invention after
application of an embodiment of the shaping slide of the
present invention.
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Fig. 6 is a longitudinal view of one embodiment of the
surgical fastening tool that includes a handle portion, a
trigger portion and an applicator.
Fig. 7 is a cross-section of the applicator of one
embodiment of the surgical fastening tool with the slide
fully extended distally.
Fig. 8 is the same cross-section of the applicator of
the embodiment of the surgical fastening tool shown in Fig.
7 but with the slide in the fully retracted position.
Fig. 9 is a three-dimensional rendering of the first
half-shell and fastener positioning spring of the applicator
shown in cross-sectional perspective in Figs. 7 and 8.
Fig. 10 is a three-dimensional rendering of the second
half-shell of the applicator and stop spring shown in cross-
sectional perspective in Figs. 7 and 8, with the first half
shell poised above.
Fig. 11 is a front view of the slide, slide actuator
and anvil rotated ninety-degrees from their depiction in
Figs. 7 and B.
Fig. 12a is a schematic front view of the preferred
slide and fastener of the present invention prior to forming
of the fastener.
Fig 12b is a schematic front view of the preferred
slide and fastener, of the present invention after the
forming of the fastener.
Fig. 12c is a three-dimensional rendering of the
preferred slide of the present invention.
Fig. 13 is a cross-sectional view of the handle portion
and trigger portion of a preferred embodiment of the
surgical fastening tool.
Fig. 14 is a three-dimensional cross-sectional
perspective view of a preferred embodiment of the fastening
tool wherein the applicator is readily detachable from the
body portion.
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Fig. 15a is a three-dimensional perspective view of the
proximal end of the slide actuator and "L"-shaped pin with
the pin in the unlocked position.
Fig. 15b is an exploded view of the handle portion
revealing the cam surfaces and recessed regions which
provide the mechanism for attaching the applicator to the
handle portion as well as the slide actuator lock and
release mechanism.
Fig. 16 is a cross-section of the preferred handle
portion of the present invention wherein the handle portion
contains a tapered slot that houses a pawl.
Fig. 17 is a three-dimensional rendering of the
preferred plunger assembly of the present invention showing
a pawl standing clear of the ratchet portion of the plunger
assembly following completion of a stroke.
Fig. 18 is a time-sequenced frontal view of the plunger
and pawl mechanism undergoing one complete cycle of
application and retraction.
Fig. 19 is a three-dimensional perspective view of the
pawl and wire spring.
Detailed Description Of The Invention
Referring more particularly to the drawings, Fig. 6
shows one embodiment of the surgical fastening tool. The
surgical fastening tool comprises a handle portion 10 an
applicator 20 and a trigger portion 30. Fig. 7 shows a cut-
away cross-section of a preferred embodiment of the
applicator portion of the device. According to the
preferred embodiment, the applicator comprises a tubular
housing 40 having an insert contained within. Although the
insert could be made as a single unit or even be
manufactured out of a single piece that forms the tubular
housing, the insert is preferably made from two cooperating
half-shells which are inserted into the tubular housing.
The half-shells preferably have a beveled outer edge which
permits crimping of the distal most end of the tubular
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housing to secure the insert. In the preferred embodiment,
the first half-shell 50 has a rounded side 52 which abuts
the tubular housing 40 and a flat side 54 that has recessed
region 70 whose surface forms one the walls of the fastener
storage channel containing fasteners 80. Above the
fasteners 80 sits a pusher 82, which rides in the fastener
storage channel. The pusher 82 continuously exerts a
downward pressure on the vertically stacked fasteners 80 by
virtue of a biased pusher spring 84.
Recessed region 70 gradually rises to the diametrical
plane of flat side 54 (diametrical relative to the tube
circumference on flat side 54) by virtue of a slanted ramp
72. A fastener positioning spring 60 attached to and flush
with the recessed portion 70 of flat side 54 of the first
half-shell 50 is biased to extend beyond both the recessed
region 70 of the flat side 54 and the most prominent plane
of the flat side 54. The spring 60 is capable of being
completely contained within a slot 90 in the first half-
shell. Finally, the first half-shell 50 has a cut-away
region 92 at the distal end of the applicator to permit
ejection of the fastener.
A perspective view of the first half-shell 50 is shown
in Fig. 9. The diametrical plane of flat side 54 appears
uppermost in the drawing. This view shows that in a
preferred embodiment the cut-away region 92 has two further
recessed regions 94a and 94b.
A second half-shell 100, shown in Fig. 10, has a flat
side 102 and a rounded side 104. Flat side 102 has a
recessed area 110 whose plane forms one of the walls of the
driving channel in which slide 120 rides. The distal end of
second half-shell 100 comprises an anvil 130 with a
triangular cross-section. Anvil 130 is a cantilever that
extends beyond the recessed area 110 across the driving
channel and into cut-away region 92 on the first half-shell
of the insert. On either side of the anvil 130 are slot
regions 140a and 140b, shown in the cross-section of Fig.
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10, which house ejector springs 150a and 150b (not shown)
Ejector springs 150a and 150b are, at their proximal end,
attached to round side 104 and are flush with its outer
circumference. However, the distal parts of the ejector
5 springs 150a and 150b are biased such that, when
unrestrained, the springs extend beyond the anvil 130 and
enter the further recessed regions 94a and 94b of first
half-shell 50. Alternatively, the cutaway region 92 may
fully accommodate the ejector springs 150a and 150b without
10 the need for recessed regions 94a and 94b. Spring 150b is
shown in phantom line in Fig. 7.
With reference to Fig. 7 the recessed region 110 of the
second half-shell has a slotted region 160 that houses stop
spring 170. Stop spring 170 is secured nearby in a radial
15 hole 171 in the second half-shell 100. Stop spring 170 is
also biased such that, when unrestrained, it extends out
beyond recessed area 110 through slotted region 200 in slide
120 and beyond joint diametrical planes of the inserts 50
and 100 to engage the fasteners.
20 Slide 120, shown in detail in Fig. 11, along with slide
actuator 190 are the only actuated parts in the preferred
embodiment of the applicator 20. According to the preferred
embodiment, slide 120 alternately restrains and releases all
the biased moving parts of the applicator 20. Slide 120 is
connected to slide actuator 190 within tube 40 at a point
beyond the proximal end of both half-shells, 50 and 100.
Alternatively, for an apparatus which does not have a
detachable applicator, slide 120 may extend all the way into
the handle portion, thus reducing the number of actuated
parts in the applicator to one
In the preferred embodiment slide 120 has a slotted
region 200, which alternately restrains and releases stop
spring 170 by allowing it to protrude through the slide.
Slide 120 forms one wall of the storage channel created by
the recessed region 70 in first half-shell 50.
CA 02582811 2007-04-04
21
The distal end of the slide 120, in the preferred
embodiment, is forked and beveled to cooperate with
triangular shaped anvil 130, as shown in Fig. 11, 12a, 12b
and 12c. This feature permits the slide width to be equal
to or less than the fastener width. In the most preferred
embodiment, the width of the slide 120, as well as that of
the storage channel created by the surfaces of recessed
region 70 and slide 120, extends almost the entire diameter
of the joined half-shells, 50 and 100.
The preferred method of applying the fastener is
demonstrated by Figs. 7 and 8. Fig. 8 shows that when the
slide 120 is fully retracted, the fastener positioning
spring 60 urges the distal-most vertically-stacked fastener
80 from the storage channel to the driving channel located
distal to slide 120. As the slide 120 is advanced in the
driving channel by virtue of the slide actuator 190, the
tines of the forked bottom of slide 120, shown in Fig. 12a,
exert a downward pressure on the first fastener 80. As the
slide 120 advances, it lifts the stop spring 170 out of
slotted region 200 of the slide 120 (not shown), out of the
storage channel where it previously restrained the second of
the stacked fasteners and into recessed region 160 of the
second half-shell piece 100. The second of the stacked
fasteners is thereby released by stop spring 170 and
advanced by the pusher 82 which is forward biased by pusher
spring 84 (not shown in Fig. 8). The second fastener thus
advances to the distal-most position in the storage channel,
a position previously occupied by the first fastener.
As demonstrated by Fig. 7, advancement of the slide as
described above also blocks fastener egress from the storage
channel along its length, thereby preventing the next
fastener from prematurely entering the driving channel.
Additional advancement of the slide 120 pushes ejector
springs 150a and 150b back into slotted regions 140a and
140b (not shown). This permits the foremost fastener to
rest on the anvil 130 until the fully advanced slide shapes
CA 02582811 2007-04-04
22
the fastener on the anvil, as demonstrated in Figs. 7, 12a
and 12b.
Once the fastener is formed on the anvil 130 and the
toes of the fastener are securely in the tissue, the slide
120 is retracted such that biased ejector springs 150a and
150b are free to extend past the end of the anvil and kick
the fastener off of the cantilevered anvil. As a result the
applicator is freed and the fastener remains securely
attached to the tissue and/or surgical material.
According to the preferred method, the slide 120 is
subsequently retracted until the stop spring 170 passes
through the slotted region 200 of the slide and hooks
underneath a third fastener in the storage channel thereby
preventing the third fastener's further advancement. Upon
further retraction of the slide 120, the biased fastener
positioning spring 60 is freed, thereby pushing the second
fastener into the driving channel space vacated by slide
120.
Although the foregoing sequence of steps is preferred,
in an alternate execution of the method, the sequence of
steps triggered by the slide's action may involve
simultaneous execution, or may even be reversed, as long as
the method achieves the objectives of not permitting two
fasteners into the driving channel at the same time, not
permitting empty firing and not permitting the device to
jam.
With respect to the handle portion 10 and the trigger
portion 30, the invention contemplates that there are many
ways to fashion these elements. However, to further the
goals of minimal jamming and misfiring by the miniaturized
tool, the invention teaches a preferred handle portion and
trigger portion, shown separately in Fig. 13, that work
consistently and reliably with the preferred applicator
embodiment and other applicator designs. In a preferred
embodiment, the handle portion 10 consists of a pistol grip
portion 12 and a barrel portion 14. The trigger portion 30
. 1. . i CA 02582811 2007-04-04
23
of the preferred embodiment comprises a trigger 302 having a
cam follower 304 which fits within the handle portion 10 and
is pivotally attached at pivot 303 to the pistol grip
portion 12 and biased by spring 306. The cam follower 304
engages a cam 308 which extends from a cooperating hinged
lever 310 that resides within the pistol grip portion 12.
The hinged lever 310 is pivotally attached near the butt of
the pistol grip portion 12 and extends through the handle
portion 10 into the barrel portion 14. The hinged lever 310
has at its upper end a fork 312 whose crotch is aligned with
the axis of the tubular housing 40 of applicator 20 (not
shown). The fork 312 is biased away from the applicator 20
(not shown) by fork biasing spring 314. The fork 312
connects to a plunger/ratchet assembly 316 which has a
distal and proximal end. The proximal end of
plunger/ratchet assembly 316 is grooved to accept the fork
312. As shown in Fig. 14, the distal end of plunger/ratchet
assembly 316 connects to slide actuator 190 which in turn
connects to slide 120 (not shown) within the applicator 20.
The trigger portion 30 is contained in a recess of handle
portion 10 which may consist of two halves fitted together,
such as l0a and lOb.
The preferred embodiment functions as follows:
squeezing trigger 302 causes lever fork 312 to be thrust
toward the distal end of the barrel portion 14 by the
response of the cam 308 to action of the cam follower 304.
Release of the trigger 302 causes fork 312 to retract to its
original position by virtue of a fork biasing spring 314 and
trigger biasing spring 306 which returns these same elements
back to their resting positions.
The limited number of fasteners deployable within a
miniaturized device may create the need for easy, reliable
reloading during extensive surgical procedures. Many
hospitals desire to have a reusable portion of the fastener
applicator tool. Fig. 14 shows a preferred embodiment in
which an applicator 20 containing stacked fasteners 80 (not
i .WI 1' CA 02582811 2007-04-04
24
shown) that is readily detachable from body portion 10 by
rotating the applicator 20 and axially moving it away from
the handle portion 10. A new applicator is readily attached
in the reverse manner. The applicator 20 thus functions as
a fastener magazine and is replaced every time a new supply
of fasteners is required.
In the preferred embodiment of this aspect of the
invention, slide actuator 190 is notched at its proximal end
to accept the drive pin 318 present on the distal end of the
plunger/ratchet assembly 316. However, because the slide
actuator 190 would otherwise freely move within applicator
when the applicator 20 is not attached to the handle
portion 10, the slide actuator 190 is locked into place by
virtue of an "L"-shaped pin 320 having a flat spot on its
15 shank.
Fig. 15a illustrates a simplified close-up of this
locking feature. The leg of "L"-shaped pin 320 passes
through hub 321 (not shown) and engages a notched region 330
of slide actuator 190. When the leg portion of "L"-shaped
20 pin 320 is parallel to the bore of the tubular housing 40,
as in Fig. 14, the shank engages notched region 330 of the
slide actuator 190 and the slide actuator is locked.
However, when the external portion of pin 320 is transverse
to the bore of the tubular housing 40, as in Fig. 15a, the
flat portion of the pin shank is free of notches 330 and as
a result the actuator 190 is free to slide axially in
response to actuation by the handle and trigger portions.
As shown in Fig. 14, the pin 320 and the proximal end of the
slide actuator 190 are preferably protected by a skirt 340
to prevent any inadvertent change in the position of the
"L"-shaped pin 320 during handling of the actuator. The
skirt 340 also protects against damage to the proximal end
of the slide actuator 190. According to this feature, the
distal end of the barrel portion 14 of handle portion 10 of
the fastener applicator tool is received within the skirt
CA 02582811 2007-04-04
340 and connected to the slide actuator 190 within the
skirt.
With reference to Fig. 14, which shows detail of the
applicator magazine attachment to the handle portion, the
5 handle portion 10 is made of two body portions, l0a and lOb,
which fit together, house the trigger 302, fork lever 312
and plunger/ratchet assembly 316. According to this
applicator magazine embodiment, the handle portion 10
comprises a socket at its distal end that is shaped to
10 receive the proximal end hub 321 of applicator 20. The
plunger/ratchet assembly 316 is fitted with a drive pin 318
for engagement with slide actuator 190 and the proximal end
of the slide actuator 190 is notched to receive the drive
pin 318. In lieu of a skirt 340, applicator 20 may simply
15 have a grip disposed about its circumference that allows the
user to grip the applicator 20 during assembly with the
handle portion 10.
In the preferred applicator magazine attachment
mechanism shown in Fig. 15b, the applicator 20 is inserted
20 into the handle portion 10, comprised of two handle halves
l0a and lOb, by sliding its proximal end into the socket of
the handle portion 10, and rotating the applicator. The act
of inserting the proximal end of the applicator 20 into the
distal end of the handle portion 10 and rotating it serves
25 several purposes: first, it locks the applicator 20 onto the
handle body 10; second, the rotation causes the "L"-shaped
pin 320 to rotate in response to a cam surface 328 thereby
freeing the slide actuator 190 from its locked position into
a ready position; third, rotation causes the notch in the
slide actuator 190 to engage the drive pin 318 on the
plunger/ratchet assembly 316; and fourth, detent structure
327 engages the shank of the "L"-shaped pin, preventing
inadvertent rotation in use. Fig. 15b shows the detail of
the mechanism for connecting the applicator to the handle.
The two handle halves l0a and lOb comprising relief grooves
323, 324, 325 and 326 and cam surfaces 328 and 329, engage
CA 02582811 2007-04-04
26
the proximal end of the actuator hub 321 for the purpose of
releasably holding the applicator to the assembled handle.
In Fig. 15b, the handle halves are shown separated and
opened out in juxtaposition to illustrate their features.
Also shown is the actuator hub 321 with slide actuator 190
locked in place by the "L"-shaped pin. The embodiment shown
here does not incorporate a skirt as in Fig. 14. On
insertion of the hub into the handle bore that is created by
the junction of handle halves 1Qa and lOb, the relief
grooves 323, 324, 325 and 326 form grooves of different
depths such that the hub may only be assembled in one
position because of the profile of the "L"-shaped pin 320.
After full insertion, clockwise rotation presses the arm of
the "L"-shaped pin against cam surface 328 and turns the arm
90 to the axis of the hub 321. Rotation is continued until
the shank of the "L"-shaped pin passes past the detent 327
at the end of the groove in the handle to lock the actuator
in position. The actuator is thus locked in place ready for
use, and cannot inadvertently back-rotate and uncouple.
After insertion, the device is ready for operation as if it
were a tool of unitary construction. Reversing this
rotation step frees the slide actuator 190 from drive pin
318, and on withdrawal, cam 329 rotates the leg of the "L"-
shape pin back into engagement with the notched region of
the slide actuator 190 on withdrawal, thereby locking the
actuator, and disconnects the applicator 20 from the handle
portion 10. If a skirt is incorporated into this attachment
apparatus as in Fig. 14, it may be integral with or attached
to the hub 321. If the apparatus is of unitary
construction, the releasable attachment mechanism may be
eliminated and the cooperating elements are non-detachably
joined.
According to another aspect of the invention, the
preferred embodiment includes a ratchet and pawl system
designed to guarantee complete, irreversible travel of the
applicator mechanism during each stroke of the application
~i I II
CA 02582811 2007-04-04
27
cycle. This aspect of the invention, shown in Figs. 16 and
17, contemplates that the plunger/ratchet assembly 316
reciprocates backward and forward within the barrel portion
14 of the handle portion 10. A tapered slot 400 is provided
in the handle portion 10 and a pawl 402 is placed within
that tapered slot. A wire pawl spring 406 extends between
posts 404a and 404b. The pawl spring 406 urges the pawl 402
into a perpendicular position relative to the direction of
plunger travel by means of a slot in the pawl. The side of
the plunger/ratchet assembly 316 that faces pawl 402 has a
series of grooves forming a ratchet 408 which extends
approximately as far as the extent of travel of the
plunger/ratchet assembly 316 within the handle portion 10.
The length of pawl 402 is somewhat greater than the distance
between the bottom of the tapered groove and the bottom of
the ratchet grooves. The pawl 402 is thus trapped at an
oblique angle between the slot 400 and the ratchet 408
during plunger travel.
Fig. 18 shows the complete fastener application cycle
with reference to the plunger/ratchet assembly 316. Once
the plunger travel is initiated and the pawl is engaged in
the ratchet, any attempt to reverse direction causes the
pawl 402 to jam between the slot 400 and the ratchet 408
thereby immediately stopping counter-travel. The
plunger/ratchet assembly thus can only move in the initial
stroke direction until the pawl travels past the end of the
ratchet 408 and out of engagement with the plunger/ratchet
assembly. At that point, the wire pawl spring 406 causes
the pawl 402 to assume a position that is perpendicular to
the ratchet 408. The initiation of travel of the
plunger/ratchet assembly in the opposite direction (the
return stroke) again places the pawl 402 into engagement
with the ratchet at an angle, but this time the pawl is
oriented in the opposite sense. Thus, the pawl's
orientation makes mid-stroke reversal impossible once again
until travel is complete and the pawl clears the other end
CA 02582811 2007-04-04
28
of the ratchet completing the cycle. By adjusting the
geometry of the ratchet and pawl as well as providing travel
stops for the plunger assembly, the device eliminates mid-
stroke reversals and thereby helps prevent jamming, non-
firing and misfiring. Fig. 19 shows in detail the spring
406 deployed in the slot of the pawl 402 so as to orient the
pawl.
While particular endoscopic devices and methods have
been described for applying fasteners, once this description
is known, it will be apparent to those of ordinary skill in
the art that other embodiments and alternative steps are
also possible without departing from the spirit and scope of
the invention. Moreover, it will be apparent that certain
features of each embodiment can be used in combination with
devices illustrated in other embodiments. For example, the
four various aspects of the invention may be mixed and
matched to create a variety of surgical fastening devices
with varying features. Accordingly, the above description
should be construed as illustrative, and not in a limiting
sense, the scope of the invention being defined by the
following claims.
