U.S. patent application number 11/900459 was filed with the patent office on 2008-01-10 for trocar system and method of use.
This patent application is currently assigned to United States Surgical Corporation, a division of Tyco Healthcare Group LP. Invention is credited to Adam Lehman, David C. Racenet, Ralph A. Stearns, Gene Stellon.
Application Number | 20080009797 11/900459 |
Document ID | / |
Family ID | 24099011 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080009797 |
Kind Code |
A1 |
Stellon; Gene ; et
al. |
January 10, 2008 |
Trocar system and method of use
Abstract
A trocar system including a cannula and an obturator assembly
being at least partially insertable through the cannula. The
obturator assembly including a housing, a penetrating tip disposed
at a distal end, an elongated shield including a guard extending
from a shaft are movable relative to the penetrating tip, and a
latch mechanism disposed generally within the housing. The latch
mechanism facilitates changing the configuration of the obturator
assembly between a fixed-shield orientation, wherein at least a
portion of the guard is maintained to extend at least partially
distal of the penetrating tip to prevent puncturing of tissue by
the penetrating tip, to a non-fixed shield orientation whereby upon
application of force to the distal end of the obturator assembly,
the guard and penetrating tip are permitted to move relative one
another to facilitate puncturing of tissue by the penetrating
tip.
Inventors: |
Stellon; Gene; (Southington,
CT) ; Racenet; David C.; (Southbury, CT) ;
Stearns; Ralph A.; (Bozrah, CT) ; Lehman; Adam;
(Wallingford, CT) |
Correspondence
Address: |
Neil D. Gershon, Esq.;DIL WORTH & BARRESE
333 Earle Ovington Boulevard
Uniondale
NY
11553
US
|
Assignee: |
United States Surgical Corporation,
a division of Tyco Healthcare Group LP
|
Family ID: |
24099011 |
Appl. No.: |
11/900459 |
Filed: |
September 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09981178 |
Oct 16, 2001 |
|
|
|
11900459 |
Sep 12, 2007 |
|
|
|
09526837 |
Mar 16, 2000 |
6319266 |
|
|
09981178 |
Oct 16, 2001 |
|
|
|
Current U.S.
Class: |
604/164.08 ;
606/185 |
Current CPC
Class: |
A61B 17/3474 20130101;
A61B 17/3417 20130101; A61B 17/3496 20130101; A61B 2017/0046
20130101 |
Class at
Publication: |
604/164.08 ;
606/185 |
International
Class: |
A61B 17/34 20060101
A61B017/34 |
Claims
1. A trocar system which comprises: a cannula forming an opening
longitudinally therethrough and having a proximally facing surface
disposed near a proximal end thereof; and an obturator assembly
being at least partially insertable through the cannula and
including: a housing disposed at a proximal end, the housing
including a base portion having a distally facing end surface
configured and dimensioned to facilitate close proximate
positioning thereof with the proximally facing surface of the
cannula; a penetrating tip disposed at a distal end; an elongated
shield including a guard extending from a shaft, the penetrating
tip and guard being movable relative one another; and a latch
mechanism disposed generally within the housing, which facilitates
changing the configuration of the obturator assembly between a
fixed-shield orientation, wherein at least a portion of the guard
is maintained to extend at least partially distal of the
penetrating tip to prevent puncturing of tissue by the penetrating
tip, to a non-fixed shield orientation whereby upon application of
force to the distal end of the obturator assembly, the guard and
penetrating tip are permitted to move relative one another to
facilitate puncturing of tissue by the penetrating tip, the latch
mechanism including: a release member having a button portion and a
camming surface; and a latch operatively associated with the
release member, the latch having a blocking surface and a mating
surface, the mating surface cooperating with the camming surface of
the release member such that upon movement of the release member
the camming surface biases the mating surface to move the latch
such that the blocking surface permits axial movement of the
shield.
2. A trocar system as recited in claim 1 wherein movement of the
release member causes the blocking surface to be displaced out of
axial alignment with the shield.
3. A trocar system as recited in claim 1 wherein the button portion
protrudes at least partially through an opening formed in the
distally facing end surface of the obturator housing.
4. A trocar system as recited in claim 1 wherein the latch is
biased such that the blocking surface is normally disposed in axial
alignment with at least a portion of the shield to prevent axial
movement thereof.
5. A trocar system as recited in claim 2 wherein the blocking
surface is disposed proximal of the at least a portion of the
shield.
6. A trocar system as recited in claim 1 wherein the release member
is configured and dimensioned such that axial movement of the
release member imparts lateral movement of the blocking surface of
the latch member.
7. A trocar system as recited in claim 1 wherein the obturator
includes a shaft fixed relative to the housing and the penetrating
tip is a flat knife blade secured to the shaft.
8. A trocar system as recited in claim 1 wherein the shield
includes an extended surface which is disposed on the shield such
that upon axial movement of the shield, the extended surface biases
the actuator member away from the latch to permit the latch to
return to its original orientation.
9. A trocar system as recited in claim 1 wherein the guard is
configured and dimensioned to completely enclose the penetrating
tip.
10. A trocar system as recited in claim 1, wherein the shield and
guard are separate elements fitted together during assembly of the
obturator.
11. A method of inserting a trocar assembly into a patient
comprising the steps of: approximating an obturator assembly with a
cannula assembly such that a button portion of a release member is
urged proximally and a camming surface of the release member
imparts lateral movement of a blocking surface of a latch such that
the blocking surface is moved to permit relative movement of the
shield and a penetrating tip of the obturator assembly; and
inserting the trocar assembly through the body wall of a patient by
pushing the trocar assembly toward the body wall such that a guard
of the shield is urged proximally to reveal the penetrating tip and
permit passage of the trocar assembly through the body wall.
12. A method of inserting a trocar assembly as recited in claim 11
wherein lateral movement of the blocking member moves the blocking
member out of axial alignment with the shield.
13. A method of inserting a trocar assembly as recited in claim 11,
further including the step of resetting the shield to a fixed
orientation distal of the penetrating tip upon passage of the
penetrating tip through the body wall and into a cavity of the
patient's body, such resetting being facilitated by axial movement
of the shield and resilient bias of the latch to a position wherein
the blocking surface is axially aligned with at least a portion of
the shield.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to trocar systems for
inserting cannulas into patients, and more particularly to modular
trocar systems and methods of assembly of trocar systems.
[0003] 2. Background of Related Art
[0004] Minimally invasive procedures are continually increasing in
number and variation. Forming a relatively small diameter temporary
pathway to the surgical site is the key feature of most minimally
invasive surgical procedures. The most common method of providing
such a pathway is by inserting a trocar assembly through the skin.
In many procedures the trocar is inserted into an insufflated body
cavity of a patient. In such procedures, trocar assemblies with
seal mechanisms are utilized to provide the necessary pathway to
the surgical site while minimizing leakage of insufflation gases
through the inserted cannula.
[0005] Trocar assemblies typically include an obturator removably
inserted through a cannula assembly. The obturator is assembled
with the cannula portion such that the obturator's sharp tip
portion extends from a distal end opening of the cannula to
facilitate insertion of the cannula through the body wall of the
patient. Trocar assemblies are commonly provided with a safety
shield of some fashion which protects against unintentional
puncturing by the sharpened tip of the obturator. Mechanisms which
control the relative movement and locking of the safety shield and
the obturator's penetrating tip exist. Such mechanisms can be
complex and often require numerous moving parts to accomplish the
release and resetting of a the safety shield lock feature so as to
permit the obturator's penetrating tip to function only when
desired to facilitate insertion of the trocar assembly and
placement of the cannula portion thereof.
[0006] A continuing need exists for novel trocar assemblies which
provide safety shield latch mechanisms which require fewer
component parts while providing increased reliability before,
during and after insertion of the trocar assembly in a patient.
SUMMARY
[0007] The present disclosure provides a modular trocar system
which overcomes disadvantages associated with previous trocar
systems. The presently disclosed modular trocar system satisfies
the need for more reliable trocar assemblies while improving
manufacturing efficiencies.
[0008] In particular, the present disclosure provides trocar system
including a cannula and an obturator assembly being at least
partially insertable through the cannula. The obturator assembly
including a housing, a penetrating tip disposed at a distal end, an
elongated shield including a guard extending from a shaft are
movable relative to the penetrating tip, and a latch mechanism
disposed generally within the housing. The latch mechanism
facilitates changing the configuration of the obturator assembly
between a fixed-shield orientation, wherein at least a portion of
the guard is maintained to extend at least partially distal of the
penetrating tip to prevent puncturing of tissue by the penetrating
tip, to a non-fixed shield orientation whereby upon application of
force to the distal end of the obturator assembly, the guard and
penetrating tip are permitted to move relative one another to
facilitate puncturing of tissue by the penetrating tip.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Various embodiments are described herein with reference to
the drawings, wherein:
[0010] FIG. 1 is a perspective view of one embodiment of the
modular trocar system constructed in accordance with the present
disclosure;
[0011] FIG. 2 is a perspective view of an obturator assembly
constructed in accordance with the present disclosure;
[0012] FIG. 3 is a perspective view with parts separated of the
obturator assembly of the embodiment of FIG. 2;
[0013] FIG. 4 is an enlarged perspective view of a latch mechanism
for a safety shield of the obturator assembly of the embodiment of
FIG. 2;
[0014] FIG. 5 is a perspective view of a shield member of the
obturator assembly;
[0015] FIG. 6 is a perspective view of a slider member of the latch
mechanism;
[0016] FIG. 7 is a perspective view of a knife assembly of the
obturator assembly;
[0017] FIG. 8 is an enlarged view of the indicated area of detail
in FIG. 7;
[0018] FIG. 9 is a perspective view of the distal end of the knife
assembly of FIG. 7;
[0019] FIG. 10 is a horizontal cross-sectional view taken through
the knife assembly of FIG. 7;
[0020] FIG. 11 is a cross-sectional view taken along section line
11-11 of FIG. 10;
[0021] FIG. 12 is a perspective view illustrating a step of
assembling the obturator assembly;
[0022] FIG. 13 is a further step of assembling the obturator
assembly;
[0023] FIG. 14 is a perspective view of the inside of a housing
cover of the obturator assembly;
[0024] FIG. 15 is a further step in the method of assembling the
obturator assembly;
[0025] FIG. 16 is a longitudinal cross-sectional view illustrating
the assembled shield member and a shield extension member;
[0026] FIG. 17 is a further step illustrating the assembly of a
knife rod with previously assembled components of the obturator
assembly;
[0027] FIG. 18 is a cross-sectional view of the proximal end of the
components of the obturator assembly illustrated in FIG. 17;
[0028] FIG. 19 is a view similar to FIG. 18, which illustrates
securement of the knife rod within the housing cover;
[0029] FIG. 20 is a perspective view illustrating assembly of a
guard member with the shield extension member;
[0030] FIG. 20A is a perspective view of the distal end portion of
the trocar assembly of FIG. 1;
[0031] FIG. 20B is a perspective view of an existing trocar
assembly design;
[0032] FIG. 21 is a longitudinal cross-sectional view taken through
the distal end of the components illustrated in FIG. 20;
[0033] FIG. 22 is a view similar to FIG. 21, showing the guard
element attached to the distal end of the shield extension
member;
[0034] FIG. 23 is a longitudinal cross-sectional view taken through
the obturator assembly;
[0035] FIG. 24 is an enlarged view of the indicated area of detail
of FIG. 23;
[0036] FIG. 25 is a longitudinal cross-sectional view taken through
the trocar assembly of the present disclosure;
[0037] FIG. 26 is an enlarged view of the proximal end components
of FIG. 25;
[0038] FIG. 27 is view similar to FIG. 25, which shows insertion of
a trocar assembly through the skin of a patient; and
[0039] FIG. 28 is an enlarged view of the proximal end components
of FIG. 27.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0040] Referring initially to FIGS. 1 and 2, one embodiment of a
modular trocar system in accordance with the present disclosure is
designated by reference numeral 100 throughout the several views.
Modular trocar system 100 is particularly adapted for use in
minimally invasive surgical procedures such as endoscopic or
laparoscopic procedures. Generally, modular trocar system 100
includes two principal subassemblies, namely an obturator assembly
110 and a cannula assembly 112. Cannula assembly 112 includes a
seal assembly 114 and a cannula 116, as described in detail further
herein.
[0041] Except where noted otherwise, the materials utilized in the
components of the presently disclosed modular trocar system
generally include materials such as either ABS or polycarbonate for
housing sections and related components and stainless steel for
components that are required to cut tissue. A preferred ABS
material is CYCOLAC which is available from General Electric. A
preferred polycarbonate material is also available from General
Electric under the trademark LEXAN. An alternative polycarbonate
material which may be utilized is CALIBRE polycarbonate available
from Dow Chemical Company. The polycarbonate materials may be
partially glass filled for added strength.
[0042] Referring now to FIGS. 3-9, and initially to FIGS. 3-6,
obturator assembly 110 includes an obturator housing 118 formed
from housing base 119 and cylindrical housing cover 120. Once the
appropriate components are positioned therewithin (as described
below), housing base 119 may be attached to cylindrical housing
cover 120 by engaging mating surfaces, for example by resilient
latches 122 formed on cover 120 interlocking with correspondingly
shaped engaging surfaces 123 (FIG. 24) formed in the housing base
119. To uniformly connect base 119 and cover 120, preferably at
least three corresponding latches 122 and engaging surfaces 123 are
provided and are spaced evenly around the circumference of cover
120 and housing base 119, respectively. Base 119 and cover 120 are
preferably molded from an ABS material and are preferably
configured and dimensioned to functionally cooperate with various
sizes of cannulas, e.g., 5-15 mm. Thus, obturator housing 118 is
adapted to be a modular component for use with a wide range of
trocar assemblies.
[0043] When fully assembled, obturator assembly 110 includes a
safety shield assembly that is movable with respect to a
penetrating tip such as, for example, knife blade 125. The safety
shield assembly includes a shaft formed from an elongated hollow
shield member 126 and a shield extension 127. A distal guard member
128 is attached to the distal end of shield extension 127.
Preferably, all of the safety shield assembly components are molded
from a polycarbonate material. Guard member 128 is preferably
formed as a "dolphin nose" to help minimize the force necessary to
penetrate the body. As shown in FIG. 5, the distal section of
elongated shield member 126 is provided with a pair of opposing
receiving holes 148 (only one is visible) to facilitate interaction
with shield extension 128, as will be described below. Elongated
shield member 126 also includes a proximal end portion such as
collar 130 having a shield position indicator, such as indicator
flag 132, extending transversely relative to elongated shield
member 126. Preferably flag 132 is colored to contrast sharply with
the surrounding housing components. For example, indicator flag 132
may be red if the surrounding housing components are white or light
colored. Proximal end portion of collar 130 includes a bearing
surface such as ledge 134 and a pair of posts 135 formed below
ledge 134 and extending transversely outwardly.
[0044] Elongated shield member 126 is disposed within a
longitudinal throughbore 136, FIG. 3, formed through cylindrical
extended portion 138 of housing base 119 with a distal end surface
of collar 130 abutting housing base 119 on a proximal face thereof.
Cylindrical extended portion 138 may be molded as part of housing
base 119 or molded separately and mounted to housing base 119,
e.g., by sonic welding. Cylindrical extended portion 138 provides
transverse support to the shield and obturator components that pass
therethrough and preferably includes an inward taper 139 at its
distal end to facilitate passage through valve/seal assemblies.
Abutment between the distal and surface of collar 130 and housing
base 119 limits distal movement of shield member 126 relative
thereto. Ledge 134 interacts with a slot 149 formed in a latch
member 150 molded as part of base 119 to assist in the angular
orientation of shield member 126 relative to housing 118.
[0045] The safety shield assembly further includes a coil spring
140 the distal end of which is seated in shield member 126 in an
opening formed at the proximal end of collar 130. Referring
temporarily to FIG. 14, housing cover 120 preferably includes a
distally directed, hollow cylindrical post 144 molded to the
proximal face thereof. Although hollow post 144 serves several
functions, initially it is noted that coil spring 140, which biases
shield member 126 toward a distal-most position is positioned
around hollow cylindrical post 144. Thus, hollow post 144 assists
in alignment of coil spring 140, e.g., to prevent kinking thereof.
Referring temporarily to FIG. 24, the diameter of coil spring 140
is preferably selected so that spring 140 fits in a gap region
between concentrically disposed collar 130 and hollow post 144.
[0046] Housing cover 120 is further provided with an open ended
slot 146 (FIGS. 2 and 14) to slidably receive position indicator
flag 132. Housing cover 120 may further be provided with indicia
(not shown) positioned adjacent open ended slot 146 to provide
additional visual indication to the user of the relative
positioning of the shield, as is known in the art.
[0047] As noted above, the shield member 126 (and therefore the
entire shield assembly) is biased in a distal-most position by coil
spring 140. A latching mechanism is provided as part of obturator
assembly 110 to prevent proximal movement of the shield assembly
until such a time as obturator assembly 110 is inserted in a
cannula assembly, e.g., cannula assembly 112, and the surgeon is
prepared to begin trocar entry.
[0048] As best shown in FIGS. 4-6, the latching mechanism includes
latch member 150 having two vertical leg portions 152 and 154
connected by a web portion 155. A pair of biasing posts 157, 159
extend outwardly, one for each side of latch member 150. Latch
member 150 is preferably molded as part of housing base 119 in
cantilevered fashion. However, latch 150 may be formed as a
separate element and secured to base 119 by suitable known
techniques.
[0049] A release member such as slider 156 is distally biased by a
coil spring 158 which is maintained in axial alignment with a lower
end of slider 156 by a post 160. The proximal end of coil spring
158 bears against the inner surface of housing cover 120 and is
maintained in position between a post 162 and a cylindrical base
164 formed in housing cover 120 (FIG. 14). The distal biasing of
slider 156 causes an arming button 166, which extends distally from
the distal face of slider 156, to project through an opening formed
in the housing base 119 (FIG. 24). Compression of obturator
assembly 110 relative to cannula assembly 112 causes slider 156 to
translate vertically in a proximal direction as will be described
further herein. As shown in FIG. 6, slider 156 includes a pair of
legs 156a, 156b which are each connected to a base portion 156c and
terminate in a crook 156d, 156e configured and dimensioned to
engage posts 157, 159 respectively, of latch 150.
[0050] In a preferred embodiment, the components described above,
namely housing base 119, housing cover 120, the latching mechanism
components, coil spring 140, cylindrical extended portion 138 and
elongated shield member 126 constitute a first modular subassembly
that may be advantageously manufactured in large quantities and
inventoried for use across a wide range of trocar assembly sizes.
As noted hereinbelow, other modular subassemblies may be
manufactured to different size specifications, e.g., 5 mm, 10 mm,
15 mm, but all would be functionally operable with the first
modular subassembly disclosed herein.
[0051] Referring to FIGS. 3 and 7-11, assembly of a second modular
subassembly including knife blade 125 will now be addressed in
detail. Knife blade 125 is preferably fabricated from stainless
steel by a suitable process, e.g., by stamping or metal injection
molding.
[0052] A proximally extending elongated portion 168 is provided to
facilitate attachment of knife blade 125 to a knife rod 170.
Elongated proximal portion 168 is provided with a slot 172 and a
notch 174. Preferably, knife rod 170 is formed by injection
molding. Knife blade 125 is positioned in the injection mold such
that when the rod material is injected into the mold, the material
flows around a web portion 176, FIG. 10, which separates slot 172
and notch 174. When the material rejoins at slot 172, it forms a
knit-line 178, FIG. 11, and attaches knife blade to the distal end
of knife rod 170. Preferably, slot 174 is provided with an arcuate
distal terminus 180 in the shape of a "cul de sac" to permit the
rod material to flow outwardly and fill terminus 180. Knife blade
125 is further provided with a pair of lateral notches 182, 184
formed on either side of web portion 176. Notches 182, 184
facilitate proper orientation of knife blade 125 in the injection
mold prior to formation of knife rod 170. Finally, knife blade 125
has a pair of sharpened cutting edges 186, 188, which converge to
form a sharp penetration point.
[0053] Referring to FIGS. 7, 8, 10 and 11, knife rod 170 has a
flexible finger 190 formed at a proximal end. Flexible finger 190
includes a cam surface 192 extending outwardly at a proximal end to
facilitate assembly of knife rod 170 with housing cover 120, as
will be described in greater detail herein.
[0054] Referring now to FIGS. 12-20, a novel method of assembly of
obturator assembly 110 is disclosed. As shown in FIG. 12, shield
member 126 and slider 156 are fit into base 119. Shield member 126
rides over slider 156 causing the slider's legs 156a, 156b to ride
on top of posts 135 on shield member 126. Slider 156 fits over
guide posts 119a, 119b and 119c such that base portion 156c is
disposed between post 119a and posts 119b, 119c. Further, legs
156a, 156b are disposed on the outboard sides of posts 119b, 119c,
respectively. Shield spring 140 and slider spring 158 are added, as
shown in FIG. 13, and housing cover 120 is snapped in place as
described above. Referring to FIGS. 15 and 16, shield extension 127
is then snapped into place at the distal end of slider 126. In
particular, shield extension 127 has a clevis formed at a proximal
end defining two flexible halves. A pair of nubs 127a, 127b snap
fit into receiving holes 148 on shield member 126.
[0055] Referring to FIGS. 17-19, knife rod 170 is slid in through
the distal end of shield extension 127, through shield 126, and
snapped in place in housing cover 120. As shown in FIGS. 18 and 19,
insertion of knife rod 170 into hollow cylindrical post 144 of
housing cover 120 causes cam surface to flex finger 190 until cam
surface 192 is adjacent recess 193 formed in housing cover 120
whereby camming surface enters recess 193 to secure knife rod 170
in cover 120.
[0056] Referring to FIGS. 20-22, guard 128 is attached to distal
end of shield extension 127. To facilitate attachment, guard 128 is
provided with a series of flexible fingers 128a, 128b, 128c, 128d
each having a raised portion formed thereon. The raised portions
lock in place in openings such as opening 127a formed near the
distal end of shield extension member 127. This unique method of
assembly is particularly advantageous in that it allows for zero
defects on the nose portion of guard 128 which translates into less
hang up of the nose portion on tissue upon insertion of trocar
assembly 100. For example, FIGS. 20A and 20B illustrate a
comparison of the distal end portions of presently disclosed trocar
assembly 100 and an existing trocar assembly design. The trocar
design shown in FIG. 20B illustrates a circular opening labeled as
"A" at the distal end. This opening enables a gap to exist between
the knife blade and the opening upon initial insertion of the
trocar assembly into a patient, thereby permitting hang-ups of the
opening on tissue to occur. The presently disclosed trocar assembly
100 reduces the likelihood of such hang-ups by utilization of the
"dolphin nose" design to eliminate the large gaps between the guard
element and the knife blade. As an additional feature, either guard
member 128 and/or knife blade 125 may be provided with a
hydrophillic coating to further reduce the insertion force required
to insert trocar assembly 100.
[0057] As shown in FIGS. 20-22, the geometries of and cooperation
between knife blade 125 and guard member 128 facilitate ease of
insertion of modular trocar system 100 through a patient's body
wall while maintaining surgeon control and, by reason of spring
biased guard 128, provide an enhanced margin of safety to internal
organs. Cutting surfaces 186, 188 are extendable beyond the slot
195 formed in guard 128. The knife tip portion defines a planar
triangular shape. The knife tip portion may initially be generally
formed by stamping or metal injection molding and the cutting edges
186, 188 finely sharpened on both sides of knife blade 125, for
example, by machining and/or polishing of the surfaces. Cutting
surfaces 186, 188 preferably extend radially outwardly to just
within the outer diameter of the cylindrical portion of guard
member 128, thereby achieving an incision which approximates the
diameter of guard member 128. By incising to the diameter of guard
member 128, the force required for inserting modular trocar system
100 through tissue, such as the patient's abdominal wall, is
reduced.
[0058] For larger diameter trocar assemblies, each of the
components of obturator assembly 110 are the same except a larger
sized knife blade and guard member are attached to knife rod 170.
Also, a larger cannula is attached to the cannula body. This
interchangeability of different sized knives and guard members with
standard sized components located proximally thereof obviates the
need to manufacture and inventory both the components and whole
units of non-modular, conventional trocar systems. In particular,
the more complex and, therefore, more expensive size-specific
elements located in the obturator housing need not be manufactured
and inventoried. The manufacturer or distributor need only assemble
the appropriate sized knife and guard member with the otherwise
standard sized control components as demand dictates.
[0059] Referring now to FIG. 1 in conjunction with and 25-28,
cannula assembly 112 of modular trocar system 100 includes a molded
cylindrical base portion 216 having transversely extending grip
portions 218 formed to extend form an annular flange formed at the
proximal end of cylindrical base 216. A series of slots 222 are
formed along the underside or distal side of grips 218. A similar
modular cannula assembly is disclosed in U.S. Pat. No. 5,807,338 to
Smith et al., the entire contents of which are hereby incorporated
by reference. It is also contemplated, that either cannula base
portion 216 or cannula 116 or both may be formed of transparent or
translucent material.
[0060] Slots 222 are particularly advantageous in two respects.
First, in assembling cannula assembly 112, there are three basic
principle components: cylindrical base portion 216 having outwardly
directing finger grips 218, a duck bill valve element 224 having a
flange 226 which is configured and dimensioned to rest on annular
flange 220 of cylindrical base portion 216 and a cannula housing
cover portion such as proximal housing element 228 which is
configured and dimensioned to rest on duck bill flange 226 and
within the outwardly directed finger grips 218. It has been found
that by coring out the underside of outwardly extending finger
grips 218 with parallel slots 222, molding sinks which had been
previously forming on the proximal side of outwardly extending
fingers 218 of cylindrical base portion 216 were significantly
reduced, thereby providing a much more reliable flat surface, as
best shown in FIG. 18, against which duck bill flange 226 may rest
and against which the upper or proximal housing element 228 may be
welded.
[0061] This greater cooperation between the two cannula housing
elements reduces the force which must be applied as between the two
housing elements during the welding process, thereby reducing the
likelihood that the duck bill valve 224 will be torqued. Torquing
of the duck bill valve 224 can potentially reduce the sealing
function of the element in the absence of a surgical instrument
inserted therethrough.
[0062] The second respect in which slots 222 are advantageous is
that on the underside of the cylindrical base portion 216 is
normally the place where the user grips the cannula the cylindrical
base portion 216. Accordingly, the slots provide an improved
gripping surface to the user.
[0063] A further feature of cannula assembly 112 is the provision
of a detachable cannula 116 which readily connects and disconnects
from cylindrical base portion 216. Cannula 116 is preferably molded
with a substantially constant inner and outer diameter. However,
cannula 116 preferably includes a slightly larger inner diameter at
its proximal end, e.g., of 2-3 cms length, to facilitate
introduction of instrumentation, and a tapered outer diameter at
its distal-most portion, e.g. over the distal-most 2-3 cms of
length, the tapered outer diameter being largest at a proximal end
thereof and smallest at a distal end thereof. In this way, molding
is facilitated while penetration force is minimized by reducing the
outer diameter of cannula 116 in the region where tissue first
makes contact and by providing a gradual taper to the outside
diameter to assist in dilation of tissue as it passes proximally
along the outer wall of cannula 116.
[0064] An elastomeric O-ring may be interposed between cylindrical
base portion 216 and cannula 116 to maintain a fluid-type seal
between cannula 116 and cylindrical base portion 216. Cannula 116
is formed of a predetermined diameter so as to form a longitudinal
throughbore 232 in communication with a passageway formed through
cylindrical base portion 216 and proximal housing element 228.
Cannula 116 is further provided with an annular flange 234 which is
particularly sized to be received in the distal end of cylindrical
base portion 216. Flange 234 is preferably a standard size such
that cannulas having different sized diameter passageways formed
therethrough may be formed with a flange that has the same
configuration and dimension as flange 234. In this manner, cannulas
of varying sized and dimensions may be interchangeably attached to
a given cylindrical base portion such as cylindrical base portion
216.
[0065] To facilitate the interconnectability of cannula 116 and
cylindrical base portion 216, a quick connect mechanism is provided
which, for example, may be by a series of engageable mating members
(not shown) formed on cannula 116 proximal of flange 234 which
interconnect cannula 116 with cylindrical base portion 216 by way
of a series of mating indented surfaces (not shown) formed along
the inner wall of cylindrical base portion 216. The two elements
are brought into engagement with each other by inserting the
proximal end of cannula 116 into the distal end of cylindrical base
portion 216 and rotating cannula 116 clockwise until the mating
members engage and lock into the mating surfaces. The two elements
may be disengaged by applying a proximally directed force to the
cannula toward cylindrical base portion 216 and rotating cannula
116 counterclockwise. This feature is particularly advantageous
during manufacture and assembly of cannula assembly 112 in that it
facilitates inventory management and manufacturing efficiencies due
to the cylindrical base portion 216 now being a single component
which is able to be utilized across multiple cannula diameter
products, the only difference being the cannula which is ultimately
secured to the cylindrical base portions at the final stage of
manufacture.
[0066] Also provided on cannula assembly 112 is a seal assembly 240
which generally includes a housing 242 and a seal member 244. A
similar seal assembly is disclosed in copending PCT Application
Serial No. PCT/US98/08970 filed May 1, 1998 by Racenet et al., the
entire contents of which are hereby incorporated by reference.
[0067] As another feature, cannula assembly 112 may be provided
with suture anchoring structure, for example suture anchor holes
219 on finger grips 218 or devises 221 formed near the proximal end
of cannula 116.
[0068] In usage, as shown in FIGS. 25-28, obturator assembly 110 is
inserted in the proximal end of cannula assembly 112. Obturator
assembly 110 is pushed into cannula assembly 112 until the bottom
of housing body 119 contacts the proximal end of cannula assembly
112. In this manner, arming button 166 of slider 156 is forced into
housing body 119 thereby causing slider 156 to rotate such that
legs 156a and 156b push latch 150 outwardly so that web portion 155
is out of axial alignment with ledge 134, as best shown in FIGS. 25
and 26. Thereafter, trocar assembly 100 is inserted through the
body wall of the patient, FIG. 27, causing the guard member 128 to
be urged proximally to reveal knife blade 125. The proximal
movement of guard member 128 and shield member 126 connected
thereto by shield extension 127 causes legs 156a, 156b to be
rotated back inwardly by posts 135. This motion pushes legs 156a,
156b upwardly and inwardly away from latch 150 so that crooks 156d,
156e, respectively, of slider 156 no longer bias latch 150,
permitting latch 150 to rest against the outer surface of ledge
134. Once the knife blade 125 and distal portion of guard member
128 pass through the body wall of the patient, the force of spring
140 causes slider 126 to move distally, thereby resetting guard
member 128 by way of ledge 134 once again blocking proximal
movement of guard member 128. Once guard member 128 has returned to
its distal (guarded) position, it cannot be retracted again until
arming button 166 is permitted to return to its distal position,
i.e., by releasing pressure from obturator assembly 110 to allow
obturator assembly 110 to separate slightly from cannula assembly
112. Once this happens, spring 158 pushes slider 156 distally to
permit legs 156a, 156b to re-engage posts 157, 159 of latch
150.
[0069] It will be understood that various modifications may be made
to the embodiments disclosed herein. Therefore, the above
description should not be construed as limiting, but merely as
exemplifications of preferred embodiments. Those skilled in the art
will envision other modifications within the scope and spirit of
the present disclosure.
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