Note: Descriptions are shown in the official language in which they were submitted.
-1- 1 336564
,
IMPROVED SAFETY TROCAR
This invention relates to trocars used to puncture
tissue for the performance of laparoscopic or arthroscopic
surgery and, in particular, to such trocars which employ a
safety device to shield the obturator point immediately
after the point has perforated tissue.
A trocar generally comprises two major components, a
trocar tube and an obturator. The trocar tube is inserted
through the skin to access a body cavity through the tube
in which laparoscopic or arthroscopic surgery is to be
performed. In order to penetrate the skin, the distal end
of the trocar tube is placed against the skin and an
obturator is inserted through the tube. By pressing
against the proximal end of the obturator the point of the
obturator is forced through the skin until it enters the
body cavity. At this time the trocar tube is inserted
through the perforation made by the obturator and the
obturator is withdrawn, leaving the trocar tube as an
accessway to the body cavity.
It has been found that often a great deal of force is
required to cause the obturator point to penetrate the 25 skin and underlying tissue. When the point finally breaks
through this tissue, resistance to penetration is suddenly
removed, and the obturator point can suddenly penetrate to
reach internal organs of the body, which may cause
lacerations and other injury to the internal organs. To
avert this danger to the patient, trocars have been
developed which carry a spring-loaded tubular shield
within the trocar tube and surrounding the obturator. The
distal end of the shield will press against the skin as
the obturatoE point penetrates the body until the
obturator has formed a perforation with a diameter
ETH-7 32
~ -2- ~ 336564
. ,
sufficient to allow the shield to pass through. At that
time the resistance of the tissue to the spring-loaded
shield is removed, and the shield will spring forward to
extend into the body cavity, surrounding the point of the
obturator. The shield thus protects the internal body
organs from inadvertent contact with the point of the
obturator. A trocar including such a safety shield is
described in U.S. Patent 4,535,773, for example.
The tubular shield in such a trocar will, however,
require the incision formed by the obturator to extend to
a considerable diameter before the resistance of the
tissue pressure has been sufficiently decreased to allow
the safety shield to spring forward. It is only when the
incision attains the diameter of the shield that the
shield is fully able to spring into the body cavity. When
the obturator employs a long, tapered cutting tip, this
tip must extend a significant distance into the body
before the incision is sufficiently enlarged to release
the safety shield. It would therefore be desirable to
provide a safety shield which will spring forward to
shield the obturator tip as soon as possible after entry
is gained to the body cavity.
In accordance with the principles of the present
invention, a safety shield for a trocar obturator is
provided which exhibits a rounded, bullet-shaped distal
end. A slot is formed in this distal end which
corresponds to the geometry of the obturator tip, through
which the tip extends during perforation of the skin.
With this distal end conforming to the geometry of the
tip, a smooth transition is provided from the tip to the
distal end of the shield, enabling the shield to closely
follow the obturator tip through the tissue. The rounded
distal end will press against the skin and tissue in close
ETH-732
` ~3~ 1 3 3 6 5 6 4
proximity to the periphery of the incision as it is
formed, and will aid in the enlargement of the incision to
enable the shield to spring forward as soon as entry is
gained into the body cavity.
It is desirable for the obturator to slide smoothly
within the trocar tube during both insertion and
retraction of the obturator. Opposing this desire is the
need to form the obturator to be nearly the same diameter
as the tube, so that the perforation will be the size of
the tube. Thus, tolerances are generally tight between
the outside diameter of the obturator and the inside
- diameter of the trocar tube. Further complication is
provided by the valve at the proximal end of the trocar
tube, which is needed to seal the proximal end during
removal of the obturator when the trocar tube and body
cavity are insufflated with gases. The valve, which
generally takes the form of a hinged flap or trumpet
valve, is spring-loaded to bear against the obturator,
thereby assuring that the valve will close automatically
upon withdrawal of the obturator of the tube. As the
valve bears against the obturator it will frictionally
disrupt the entry and withdrawal of the obturator, and at
times can even jam and lock the obturator within the
trocar tube.
In accordance with a further aspect of the present
invention, the valve within the proximal end of the trocar
tube is oriented at an acute angle with respect to the
trocar tube when the valve is closed. Ease of entry of
the obturator or any endoscopic instrument is afforded
when the shielded tip of the obturator or instrument
presses against the angularly disposed valve, and the
angular orientation minimizes jamming of the obturator or
instrument and valve within the trocar. In a preferred
ETH-732
1 336564
-- 4
embodiment the valve is manually controllable in
discrete positions for insufflation, desufflation,
and valve closure in concert with the operation of a
gas fitting.
Further patient safety would be provided by
preventing the sudden extension of the obturator
into the body cavity as the obturator tip fully
penetrates the tissue. In accordance with yet
another aspect of the present invention, means are
provided which permits only incremental advancement
of the obturator as tissue penetration proceeds.
Such incremental advancement is provided by a
ratchet or screw mechanism, for instance.
It would further be desirable to provide the
safety of the trocar with the safety shield, but in
a device which reduces the component complexity of
the trocar and tube with the spring-loaded safety
shield. In accordance with still another aspect of
the present invention, the trocar tube is spring-
loaded and employed as the safety shield. Thus, as
the obturator point breaks through the tissue, the
trocar tube will spring forward automatically into
the body cavity, thereby providing shielding about
the tip of the obturator.
According to a broad aspect of the present
invention, there is provided a trocar including a
trocar tube having a proximal end and a distal end.
An obturator, having a perforating tip, extends
through the tube to perforate tissue at the distal
end of the tube. The trocar comprises an
incremental advancement means, cooperating with the
obturator, for permitting incremental distal
advancement of the obturator.
- 4a - l 336564
_
In the drawings:
FIGURES 1-4 illustrate the use of the trocar
tube to provide shielding of the obturator tip;
FIGURES 5a-8 illustrate a trocar safety
shield with a bullet-shaped nose;
FIGURES 9-llb and 18 illustrate operation of
a trocar with a bullet nosed shield;
~ 1 336564
_ -5-
FIGURES 12-12d illustrate a bullet nosed safety shield
when used with a triangular-pointed obturator;
-
FIGURES 13-15b illustrate operation of a trocar with a
bullet nosed shield and a triangular-pointed obturator;
FIGURES 16 and 17 illustrate the penetration of tissue
by a trocar with a bullet nosed safety shield;
FIGURES 19-21 illustrate a trocar with an angularly
disposed valve at the proximal end of the trocar tube;
`- FIGURE 22 illustrates apparatus for permitting only
incremental advancement of the obturator of a trocar;
FIGURES 23-26 illustrate a control on a trocar for
regulating insufflation of the body; and
FIGURES 27 and 28 and obturator and shield which
requires only a short extenstion of the obturator from the
distal end of the shield.
A safety trocar constructed in accordance with the
principles of the present invention is shown in FIGURE 1.
The trocar includes a trocar tube or cannula 10 having an
open distal end 12 and an open, flanged pro~imal end 14.
The proximal end 14 is mounted in a trocar handle 16. A
spring 18 is located inside the handle and abuts the
flanged end of the trocar cannula 10 and a stop 19 within
the handle 16. There is an aperture 20 at the proximal
end of the handle 16 which is surrounded by a gasket ring
22.
An obturator 24 is slideably and removeably located
within the trocar cannula and is inserted into the handle
ETH-732
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and trocar cannula by way of the aperture 20. At its
proximal end is an obturator handle 26, and the distal end
of the obturator is sharpened to a point 28. The safety
trocar of FIGURE 1 is used to puncture a hole in soft
tissue by placing the distal end 12 of the trocar cannula
10 against the tissue, and pressing against the obturator
handle 26. As pressure is exerted against the obturator
handle, the trocar cannula 10 begins to compress the
spring 18 inside the trocar handle 16 and the trocar
cannula retracts into the handle 16. This retraction of
the trocar cannula exposes the obturator point 28, which
punctures the tissue. FIGURE 2 shows the spring 18 fully
-~ compressed within the trocar handle 16 and the obturator
- point 28 fully exposed beyond the distal end 12 of the
trocar cannula. When the obturator point 28 breaks
through the inner surface of the tissue, the spring-loaded
trocar cannula 10 will spring forward around the obturator
24, shielding the obturator point to prevent inadvertent
contact of the point with internal organs of the body
inside the tissue being punctured.
FIGURE 3 shows a safety trocar in which like reference
numerals refer to the elements previously described in
FIGURE 1. In FIGURE 3 the obturator 24 is enclosed in a
bullet nosed obturator shield 32. The obturator shield 32
is flanged at its proximal end to engage a spring 30
within the obturator handle 26. At its distal end the
obturator shield has a slotted bullet-shaped nose 34. An
end view of the bullet nose 34 is shown in FIGURE 5a, with
its slot 36. The slot 36 is seen to extend radially to
the outer periphery of the bullet nose at the distal end
of the obturator shield 32. In FIGURE 3 the springs 18
and 30 are shown in their uncompressed positions.
When pressure is initially exerted at the obturator
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,
handle 26, the spring 30 within the obturator handle
compresses, as shown in FIGURE 4. This compression of the
- spring 30 causes the obturator point 28 to extend beyond
the bullet nose 34 of the shield through the slot 36, as
shown in FIGURE 5b. Further exertion of pressure at the
handle 26 will cause the trocar cannula to compress the
spring 18, and the obturator point will then begin to
extend out the distal end 12 of the trocar cannula 10.
The extended obturator point will then puncture the tissue
at the distal end of the trocar cannula until the point
breaks through the inner surface of the tissue. At that
time the resistance at the distal end of the trocar will
f ~ be removed, and the spring 18 will extend the trocar
cannula 10 forward about the point 28 of the obturator.
When the obturator and obturator handle are withdrawn from
the trocar cannula, the bullet nosed shield will continue
to protect the point of the obturator after it has been
used. The spring-loaded trocar cannula 10 provides
protection against accidental puncture of an organ within
the body, and the shield 12 continues to provide
protection against user injury after the obturator is
withdrawn from the trocar cannula.
The bullet nosed end 34 of the shield 32 is shown in
enlarged views in FIGURES 6-8. FIGURE 6 shows an enlarged
end view of the bullet nose 34 with a star-shaped slot
36. In the side view of FIGURE 7, the slot 36 is seen to
extend toward the rear of the shield as indicated at 36a.
The sharpened edges of the star-shaped obturator point
will thus extend radially through slots 36a to the outer
perimeter of the shield, and will hence cut a puncture the
same diameter as the outer diameter of the shield 32.
When the puncture is the same size as the shield, the
shield is enabled to readily spring forward to protect the
point of the obturator as it breaks through the inner
ETH-732
-8- 1 336564
.
surface of the tissue. The cross-sectional view of the
bullet nose 34 in FIGURE 8 shows the rearward extension of
the slot 36a in which the edges of the obturator point
slide, and the widened inner diameter 39 within the shield
proximal the nose for the shaft of the obturator. The
bullet nose 34 of the shield aids penetration through the
punctured tissue and improves the blending between the
obturator facets and the cannula, thereby improving the
responsiveness of the spring-loaded cannula.
Operation of the trocar with bullet nosed shield of
FIGURES 3-8 is shown in FIGURES 9-11. FIGURE 9 is a
perspective view of the trocar with the trocar cannula 10
compressed inside the trocar handle 16 so that the bullet
nose 34 of the shield extends from the distal end 12 of
the trocar cannula. An end view of the distal end of the
instrument is shown in FIGURE 10. FIGURE lla is an
enlarged side view of the distal end of the instrument of
FIGURE 9, with the bullet nose 34 extended and the
star-shaped obturator point 28 still retracted within the
shield. In FIGURE llb the obturator point 28 is shown
extended from the slot 36 of the bullet nose 34.
FIGURES 12-12d are similar to FIGURES 6-8, and show
the bullet nose 34 of the shield 32 when used with a
triangular-pointed obturator. FIGURE 12 shows the bullet
nose 34 in cross-section, with slot 36a extending along
the side of the shield. FIGURE 12a is a view of the
distal end of the bullet nose, showing the triangular slot
36 extending to the periphery of the shield. FIGURES 12b,
12c, and 12d are cross-sectional views taken as indicated
for areas B, C, and D of FIGURE 12.
Operation of the trocar with a triangular pointed
obturator is as shown in FIGURES 13-15b. FIGURE 13 is a
ETH-732
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,
perspective view of the trocar, with the trocar cannula
pressed into the handle 16 to reveal the bullet nose 34 of
the shield at the distal end 12 of the trocar cannula.
The indicator on the obturator handle is in the ~on"
position, indicating to the user that the obturator point
28 is retracted within the bullet nosed shield 32. FIGURE
14 shows the distal end of the instrument and the
trianglar point 28 of the obturator within the triangular
slot 36. FIGURE 15a shows the bullet nose 34 of the
shield 32 entending beyond the distal end 12 of the trocar
cannula 10, with the obturator point 28 still within the
bullet nose 34. FIGURE 15b shows the obturator point 28
-~~ in its extended position. It may be seen that the edge 29
of the obturator point 28 is fully eztended to the outer
periphery of the bullet nosed shield 32 so as to cut a
puncture of the same diameter as that of the shield. The
three semi-circular fingers of the rounded bullet nose 34
will then fold the three opposing flaps of tissue aside as
the shield 32 springs forward around the obturator point
28 when the puncture is made. In addition there is less
trauma to the skin caused by pressing the rounded bullet
nose fingers against the tissue as compared to the trauma
caused by a tube-like shield.
An embodiment of an obturator and shield which
requires only a short extension of the obturator point is
shown in FIGURES 27 and 28. In this embodiment there are
no slots 36a extending along the sides of the shield from
the end slot 36. Instead, the obturator point 28 cuts
only to a radial dimension 31 at the outer edges of the
point, within the inner diameter 34' of the shield. In
prior art instruments which cut to this radius, the
obturator point must be extended out of the shield to the r
blend 37 of the point 28 and the round shaft 33 of the
obturator. In the illustrated embodiment, the obturator
ETH-732
1 336564
--10--
,
point 28 need be extended only half this distance from the
bullet nosed shield 34 in order to achieve a cut of the
- full point diameter.
In the embodiment of FIGURES 27 and 28 the hemispheric
bullet-shaped nose of the shield is seen to comprise three
distal lobes, 134a, 134b, and 134c, each with a
semicircular distal end 135a, 135b, and 135c which define
the slot through which the obturator point 28 extends.
The triangular pyramidal obturator tip 28 has three
substantially flat surfaces or faces 128a, 128b, and 128c
which are ground to blend into the cylindrical shaft 33 of
~; the obturator as shown at 37. FIGURE 28 shows that each
lobe 134a, 134b, and 134c is thickened to have a
substantially flat inner surface 136a, 136b, 136c, one of
which is shown in this FIGURE. This inner surface
contacts and fits against the proximal surface of the
corresponding face of the obturator tip when the tip is
fully extended, at which time the proximal edge 137a,
137b, 137c of each thickened lobe is substantially aligned
with the blend 37 of each face. Thus, the geometry of the
bullet-shaped nose is closely aligned with that of the
obturator tip, and the lobes will fit against the faces of
the tip and follow the tip into the perforation as it is
cut by the tip. The lobes will spread the edges of the
perforation to accommodate the bullet-nosed shield and the
shield will then spring forward to protect the obturator
tip as soon as the tip breaks through the tissue.
FIGURES 16 and 17 compare operation of the safety
trocar of the present invention with that of prior
instruments. Both FIGURES show trocars in operation just
as the obturator tip breaks through the tissue 50. FIGURE
17 illustrates operation of known instruments, in which
the shield for the obturator point is a tubular shiel`d
ETH-732
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,
44. This shield engages the tissue being punctured as
shown at 45. This shield is not able to overcome the
- tissue resistance at 45 and spring forward to protect the
obturator point until the obturator has made a puncture
with a radius as indicated by Rm. When this occurs, the
obturator point 28 is already well within the body and may
have already damaged organs inside the body. By
comparison, the bullet nosed shield 34 contacts the tissue
outside the puncture site at points indicated at 35 in
FIGURE 16. These contact points are at a much smaller
radius Rd from the obturator point 28. This smaller
radius, together with the spherical shape of the nose 34,
- enable the bullet nosed shield to spring forward through
the puncture at a much earlier time than the prior tubular
shield, thereby protecting the point 28 of the obturator
as soon as it breaks through the tissue.
By virtue of this superior protective action, a trocar
can be made to rely solely on the protective action of the
spring-loaded shield 34 without the spring-loaded trocar
cannula. An embodiment of this type is shown in FIGURE
18. The trocar cannula 70 is attached at its proximal end
to the cannula handle 16. The obturator shield 32 and
obturator 24 slide within the trocar cannula 70. A flange
66 at the proximal end of the shield 32 engages the spring
30, and is slideably engaged within a passageway 68 in the
obturator handle 26. The bullet nose 34 of the shield is
shown extended beyond the distal end 12 of the trocar
cannula, but with the obturator point 28 still retracted
within the shield. As the spring 30 is compressed when
the bullet nose 34 contacts the tissue being punctured,
the obturator point 28 will extend beyond the bullet nose
and puncture the tissue. Once the point has broken
through the tissue, the bullet nosed shield 32 will spring
through the puncture to shield the point 28 within the
ETH-732
` -12- 1 336564
body.
- Prior to and after retraction of the obturator from
the body, the body at the puncture site is generally
insufflated with air. To prevent the air from escaping
through the puncture, the trocar cannula and handle are
generally equipped with a valve mechanism to prevent air
leakage. FIGURE 19 is a cross-sectional view of the
trocar handle 16, showing a proximal tubular passageway 80
which is angled at its distal end. At the distal end of
the passageway 80 is a flap valve 74 which is hinged at
75. A rubber-like sealing pad 78 is located on the side
~~ of the flap valve which contacts the distal end of the
passageway 80. At the proximal end of the passageway 80
is a replaceable gasket 72 which has an aperture 73. The
use of gaskets with different diameter apertures permits
the trocar to be used with instruments of many different
sizes. The internal diameter of the passageway 80 is
sized to allow the shield 32 to smoothly slide through the
passageway with the gasket 72 providing a seal around the
shield. FIGURE 21 shows an enlarged view of the trocar
handle 16, the obturator handle 26, the passageway 80, and
the gasket 72.
FIGURE 20 shows the shield 32 and obturator 24
completely inserted within the trocar cannula 70. After
the puncture is made, the shield 32 and obturator 24 are
withdrawn from the trocar cannula 70, and the flap valve
74 swings shut against the distal end of the passageway 80
as the shield 32 clears the distal end of the passageway.
The flap valve swings closed under the force of a spring
76. The distal end of the passageway 80 is thus securely
sealed against air leakage while the shield is still
sealing the proximal end of the passageway 80 at the
gasket 72. The angled distal end of the passageway 80
ETH-732
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.
- permits the flap valve to be easily pushed open by the
shield, or any endoscope instrument and prevents the
- shield from becoming jammed between the sealing pad 78 and
the passageway as the flap valve closes. The distance
between the flap valve 74 and the proximal gasket 72
ensures that the valve will be completely closed before
the shield is removed from the gasket. Additionally the
design of the trocar of FIGURE 20 enables a user to
selectively expose the obturator point or retract it into
the shield.
During some surgical procedures, a substantial amount
~ of force is required to cause the obturator to puncture
the tissue. The sudden release of back pressure as the
puncture is achieved often causes the obturator to burst
through the tissue and injure organs within the body.
FIGURE 22 shows a trocar which prevents this sudden
breakthrough and extension into the body. Located within
the obturator handle 26 is a mechanism 92 connected to the
obturator or shield 32 which permits only incremental
advancement of the obturator. In FIGURE 22 this mechanism
92 is illustrated as a pivoting toothed cam 94, which
engages matching teeth 96 on the shield 32. A return
spring 98 is connected to the proximal end of the cam 94
so that the mechanism 92 will e~hibit a ratchet-like
operation, permitting extension of the obturator in small
incremental distances. The mechanism 92 permits the
obturator to be extended only a total distance ~P" into
the body, which is sufficient to provide a puncture of the
desired diameter. The ratchet mechanism 92 is only
illustrative of the types of mechanisms that may be
employed. Other suitable mechanisms include a linear or
rotary double pawl clock escapement, or a coarse pitch
screwing action whereby the obturator is incrementally
advanced as the obturator handle is turned. Either these
ETH-732
- -14- 1 336564
- or other suitable mechanisms will permit only incremental
advancement of the obturator while providing tactile
-- feedback to the surgeon indicating that the obturator is
being advanced through the tissue.
S
FIGURES 23-26 illustrate a control on the trocar
handle for enabling regulation of the insufflation of the
body. The control includes a pivotally mounted lever 100
located on the top of the trocar handle 16. The lever 100
is moveable to three discrete positions: off, insufflate,
and desufflate. At a position just forward of the lever
100 is an insufflation fitting 102, located over a
- passageway 108 which leads to the interior of the handle
16. Connected to the pivot shaft 104 of the lever is a
key 106, which pivots with the lever.
FIGURE 25 is a plan view of the handle 16 with the top
of the handle removed. In this view the key 106 is seen
to have two ears 112 and 114, each with an upward
extending central dimple. As the key is rotated with the
lever, the dimples trace an arc along the top of the
handle. Located in this arc of travel are the passageway
108 and two depressions 120 and 122, which act as detent
positions for the dimples on the key ears 112 and 114.
Located on the proximal extension of the key 106 is a
pointer 110, which opposes an upward extension 75 of the
flap valve 74 within the handle 16 (see FIGURE 24).
FIGURE 24 illustrates that the angled distal end of the
passageway 80 may have its own circular gasket 78' located
around the distal end of the passageway.
When the lever 100 is rotated to the ~off" position,
the dimple on the key ear 112 clicks into the depression
120 and the dimple on the key ear 114 fits into the inner
end of the insufflation passageway 108, thereby sealing
ETH-732
1 3365~4
- 15 -
the passageway. With the passageway 108 sealed,
pressurized air inside the trocar cannula 70, the
trocar handle 16 and the body will not leak out of
the insufflation fitting. The flap valve 74 seals
the distal end of the passageway 80 at this time.
When it is desired to insufflate the body, a
source of pressurized gas is connected to the
insufflation fitting 102 and the lever is moved to
the "insufflate" position as shown in FIGURES 23, 24
and 25. In this position, the passageway 108 is not
blocked by the key 106 and pressurized gas may enter
the interior of the handle and the trocar cannula
through the insufflation fitting 102, insufflating
the body. After the body has been properly
insufflated with gas, the lever 100 may be moved
back to the "off" position to seal the pressurized
gas in the trocar, and the gas source may be removed
from the fitting 102. When it is desired to
desufflate the body, the lever 100 is pivoted to the
"desufflate" position as shown in FIGURE 26. The
pivoting of the lever causes the key pointer 110 to
contact the flap valve extension 75 and swing the
flap valve away from its sealing position at the
distal end of the passageway 80. Pressurized gas
within the handle and trocar cannula will thus be
vented through the passageway 80. As the key swings
to its detent position, the dimple on the key ear
114 clicks into the depression 122 and the dimple on
the key ear 112 seals the passageway 108 to prevent
the venting of air through the passageway 108 and
the insufflation fitting 102.
This application is a division of C~n~ian
Patent Application Serial No. 604,666 filed July 4,
1989.
