U.S. patent application number 09/825804 was filed with the patent office on 2001-10-11 for safety shielded, reusable trocar.
Invention is credited to Cox, William T. II, Wolf, Philip L..
Application Number | 20010029387 09/825804 |
Document ID | / |
Family ID | 22371694 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010029387 |
Kind Code |
A1 |
Wolf, Philip L. ; et
al. |
October 11, 2001 |
Safety shielded, reusable trocar
Abstract
A safety shielded, reusable trocar consisting of a trocar
cannula subassembly, a safety shield control mechanism, and a
separate obturator subassembly. The trocar cannula subassembly
includes an outer cannula attached to a main housing having a
central bore in which a spring biased, inner cannula is slidably
and removably inserted, and an upper housing, removably secured to
the main housing, having a central bore which is aligned
longitudinally with the bore of the main housing and in which
sealing means is removably secured. The obturator subassembly
includes an elongated obturator having a replaceable and rotatable
knife, an elongated shaft, an arcuate shaped cap, and which extends
through the upper housing, sealing means, main housing, inner
cannula, and outer cannula. The safety shield control mechanism,
located in the main housing and removably engaged with the inner
cannula, allows for positive and easily verifiable engagement and
disengagement of the inner cannula as a safety shield for the
obturator knife. When the trocar cannula subassembly and safety
shield control mechanism are coupled proper operation of the safety
shield can be verified without the obturator subassembly being
inserted in the inner cannula. In operation, the obturator
subassembly, upper housing, and sealing means can be completely
removed from the trocar assembly to allow unobstructed access
through the inner cannula to the patient's internal cavity for
removal of specimens or insertion of equipment. After use, the
entire trocar assembly can be easily disassembled for cleaning,
sterilization, and reuse.
Inventors: |
Wolf, Philip L.; (San
Antonio, TX) ; Cox, William T. II; (San Antonio,
TX) |
Correspondence
Address: |
SHARON E. LYTLE
MCGLINCHEY STAFFORD
1001 MCKINNEY, SUITE 1500
HOUSTON
TX
77002
US
|
Family ID: |
22371694 |
Appl. No.: |
09/825804 |
Filed: |
April 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09825804 |
Apr 4, 2001 |
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08541013 |
Oct 11, 1995 |
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6238407 |
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08541013 |
Oct 11, 1995 |
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08117233 |
Sep 7, 1993 |
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Current U.S.
Class: |
606/184 ;
606/167 |
Current CPC
Class: |
A61B 2017/00473
20130101; A61B 2090/0813 20160201; A61B 17/3496 20130101 |
Class at
Publication: |
606/184 ;
606/167 |
International
Class: |
A61B 017/32 |
Claims
We claim:
1. A safety shielded trocar assembly comprising: a. a trocar
cannula subassembly having an outer cannula attached to a main
housing and an inner cannula removably interposed with said outer
cannula and said main housing, said inner cannula being axially
movable relative to said outer cannula between a normally extended
position and a retracted position; and b. biasing means acting on
the rear end of said inner cannula, whereby said inner cannula is
forced to said retracted position when said trocar assembly is
being forced against a relatively immovable object and is biased by
said biasing means to said extended position once the trocar
assembly is removed from the relatively immovable object whereby
the proper operation of said inner cannula as a safety shield for
an obturator can be verified without said obturator being
interposed with said inner cannula.
2. A safety shielded trocar assembly comprising: a. a trocar
cannula subassembly having an outer cannula attached to a main
housing and an inner cannula removably interposed with said outer
cannula and said main housing, said inner cannula being axially
movable relative to said outer cannula between a normally extended
position and a retracted position; b. biasing means acting on the
rear end of said inner cannula to bias said inner cannula to said
normally extended position; and c. inner cannula control means
located in said main housing, said inner cannula control means
acting on said inner cannula, whereby said inner cannula is forced
to said retracted position when said trocar assembly is being
forced against a relatively immovable object and is biased by said
biasing means to said extended position once the trocar assembly is
removed from the relatively immovable object whereby the proper
operation of said inner cannula as a safety shield for an obturator
can be verified without said obturator being interposed with said
inner cannula.
3. A safety shielded trocar assembly for providing communication
through an anatomical organ structure comprising: a. an elongated
obturator having a piercing tip at its front end, an elongated
stem, and a base at its other end; b. a trocar cannula subassembly
in which said obturator is removably housed, said trocar cannula
subassembly having an outer cannula attached to a main housing and
an inner cannula removably interposed with said outer cannula and
said main housing, said inner cannula being axially movable
relative to said outer cannula between a normally extended position
and a retracted position; c. biasing means acting on the rear end
of said inner cannula, whereby said inner cannula is forced to said
retracted position to expose said piercing tip when said trocar
assembly is being inserted through the wall of the anatomical organ
structure and is biased by said biasing means to said extended
position to shield said piercing tip once the trocar assembly has
pierced the wall.
4. A safety shielded trocar assembly for providing communication to
a body cavity during insufflatory surgical procedures wherein said
operative body cavity is maintained under gas pressure during said
surgical procedure comprising: a. an elongated obturator having a
piercing tip at its front end, an elongated stem, and a base at its
other end; b. a trocar cannula subassembly in which said obturator
is removably housed, said trocar cannula subassembly having an
outer cannula attached to a main housing and an inner cannula
removably interposed with said outer cannula and said main housing,
said inner cannula being axially movable relative to said outer
cannula between a normally extended position and a retracted
position, said inner cannula having a passage adapted for removably
housing said obturator; c. biasing means acting on the rear end of
said inner cannula, whereby said inner cannula is forced to said
retracted position to expose said piercing tip when said trocar
assembly is being inserted through the wall of the body cavity and
is biased by said biasing means to said extended position to shield
said piercing tip once the trocar assembly has pierced the wall; d.
an upper housing removably secured to said main housing opposite
said outer cannula having a passage adapted for receiving said
obturator therethrough; e. means for sealing said upper housing
removably located in said upper housing, said sealing means having
an upper seal coaxially disposed about said upper housing passage
through which said obturator is adapted to extend and a flapper
seal coaxially disposed about said upper housing passage to seal
said upper housing passage when said obturator is removed whereby
during the surgical procedure the operative body cavity is
maintained under gas pressure, and during the surgical procedure
said obturator, said upper housing, and said sealing means may be
removed to allow unobstructed access through said inner cannula to
the body cavity.
5. In a trocar assembly comprising an elongated obturator having a
piercing tip at its front end, an elongated trocar tube in which
the obturator is housed, a tubular protective shield mounted
concentrically around the obturator and being axially movable
relative to the obturator between a normally extended position and
a retracted position, and biasing means acting on the rear end of
the protective shield, whereby the shield is forced to said
retracted position to expose the piercing tip when the trocar is
being inserted through the wall of a body cavity and is biased by
said means to said extended position to shield the piercing tip
once the trocar has pierced the wall, the improvement wherein said
trocar tube has a removable chamber housing means for sealing said
trocar tube whereby said chamber, said sealing means, said
obturator, and said protective shield may be removed to allow
unobstructed access through said trocar tube to the body cavity.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Applicant's invention relates to surgical instruments and,
more particularly, to trocars. Trocars are used to pierce or
puncture an anatomical cavity to provide communication with the
inside of the cavity during a surgical procedure.
[0003] 2. Background Information
[0004] Endoscopic surgery, particularly laparoscopic surgery, is
currently becoming a significant method for performing surgeries.
It is projected that by the year, 2000 half of all surgical
procedures will be performed endoscopically. Laparoscopic surgery
has become the surgical procedure of choice because of its patient
care advantages over "open surgery."
[0005] For the past several decades, endoscopic surgery has been
available as a method of diagnosis and, for a very limited number
of disorders, a treatment. Until recently, a factor limiting the
types of surgeries that could be performed laparoscopically was the
ability to employ intraoperative assistance. In the past,
endoscopes allowed only direct visualization by the surgeon, such
as the endoscope disclosed in U.S. Pat. No. 4,254,762 issued to
Yoon. This led to the situation where the surgeon had one hand
holding the laparoscope to his eye and then had only one hand
available to operate.
[0006] Fortunately, miniaturization of video camera computer chips
has led to the development of video cameras that can easily be
attached to an endoscope or laparoscope. During surgery, connecting
a video camera and monitor to the laparoscope enables all the
operating room personnel to view the surgical procedure, rather
than just the surgeon. Thus, the operating room personnel are able
to provide operative assistance just as they do with open surgery.
The type and number of surgical procedures amenable to laparoscopic
surgery is presently one of the most rapidly developing areas of
medicine.
[0007] The pivotal advantage of laparoscopic surgery over open
surgery is the decreased post-operative recovery time. In many
instances, a patient is able to leave the hospital within twenty
four hours after laparoscopic surgery has been performed. This is
compared to a five day to ten day hospitalization necessary to
recover from an open surgical procedure. Additionally, laparoscopic
surgery provides a decreased incidence of post-operative abdominal
adhesions and decreased post-operative pain with enhanced cosmetic
results.
[0008] An essential medical instrument for endoscopic procedures is
the trocar. Trocars are sharp, pointed surgical instruments used to
puncture the wall of an anatomical cavity. The trocar consists of a
tube or cannula and a cutting element called an obturator or
stylet. The obturator fits within the cannula and has a sharp
piercing tip at its end.
[0009] A conventional laparoscopic trocar insertion procedure
usually follows insufflation of the abdominal cavity with CO.sub.2
gas. The introduction of CO.sub.2 gas into the abdominal cavity
lifts the abdominal wall away from the internal viscera. Once this
is done, the abdominal wall is penetrated with the trocar. After
insertion of the trocar through the abdominal wall, the surgeon
removes the obturator leaving the cannula or tube protruding
through the body wall. A laparoscope or laparoscopic instruments
can then be inserted through the cannula to view internal organs or
perform surgical procedures.
[0010] Penetrating the wall of the abdominal cavity with the trocar
is done quickly. The sharp point of the obturator encounters great
resistance from the skin, muscle, and tissue membranes of the
abdominal wall while it is being pushed through these structures.
Once the trocar's sharp point and blade pass through the abdominal
wall and into the cavity, the resistance to the trocar drops
quickly. Unless the surgeon immediately stops pushing the trocar
just as soon as penetration of the abdominal wall is complete,
there is a chance that the trocar will penetrate further into the
abdominal cavity and injure internal organs.
[0011] Within the abdominal cavity, the obturator's sharp point
could easily injure or cut an internal organ upon the slightest
contact. If an internal organ is inadvertently injured or cut,
unless immediate and massive hemorrhage occurs, the injury may not
become apparent until long after completion of the surgery. At a
minimum, such an injury will delay a patient's recovery and, more
likely, could seriously endanger the patient's health. Additional
corrective surgery on an open basis may be required, subjecting the
patient to additional risks and costs.
[0012] Prior to 1987, the only trocars available for laparoscopic
use were instruments made from stainless steel, such as those
disclosed in U.S. Pat. No. 3,994,287 issued to Turp et al., and
U.S. Pat. No. 3,613,684 issued to Sheridan. A problem common to all
of these "classic" trocars is that they do not have a safety shield
which covers the sharp, cutting tip of the obturator once it
pierces the cavity wall.
[0013] Several changes and additions have been made on the
functional design of these classic trocars. The most significant
improvement on the classic trocar is the addition of a
spring-loaded safety shield that snaps forward to cover the sharp
point and blade of the obturator once the trocar has penetrated the
abdominal wall, such as those disclosed in U.S. Pat. No. 4,601,710
issued to Moll, U.S. Pat. No. 4,654,030 issued to Moll et al. and
U.S. Pat. No. 4,535,773 issued to Yoon. In these devices, the
safety shield is a plastic sleeve which is concentrically mounted
to the obturator. Because of this safety feature, trocars with a
spring loaded safety shield have become the most used trocars in
laparoscopic surgery.
[0014] However, these spring loaded safety shields have cumbersome
safety shield control mechanisms which are difficult to tell if the
safety shield is armed or engaged. To be sure of the safety
shield's operation, a surgeon will need to verify the proper
operation of the safety shield prior to use. Since the safety
shields are mounted to the obturator, surgeons are required to test
the safety shield's operation with the obturator in place by
manually pressing the safety shield of the trocar. Unfortunately,
this results in many slight puncture wounds being experienced by
the surgeons as they are attempting to vefify the safety shield's
operation.
[0015] Currently, laparoscopic trocars with the spring loaded
safety shields are manufactured only as a thin wall plastic
disposable instruments. These light weight plastic instruments are
used once and then discarded as medical waste, adding significantly
to the already escalating health care costs. For example, the
single use disposable plastic trocars cost approximately sixty five
dollars to ninety dollars each. Usually two to four trocars are
used for each laparoscopic procedure. Thus, surgical costs are
unnecessarily increased about two hundred dollars to three hundred
and fifty dollars per laparoscopic procedure, as well as adding to
the overbearing problem of medical waste by the use of these
disposable trocars. Presently, however, the increased health care
cost has been unavoidable because the only safety shielded trocar
available was a disposable item. No one had invented a easily
disassembled, easily cleaned, sterilized, and easily reassembled
for reuse, safety shielded trocar.
SUMMARY OF THE INVENTION
[0016] Accordingly, it is an object of the present invention to
provide a safety shield which can be tested for proper operation
without the obturator being located in the cannula.
[0017] It is another object of the present invention to provide a
safety shield control mechanism which is easy to verify if the
safety shield is armed or safe.
[0018] It is further object of the present invention to provide a
safety shield which is removable and separate from the
obturator.
[0019] It is still another object of the present invention to
provide a reusable trocar with a safety shield which is easily
disassembled, easily cleaned, sterilized, and easily reassembled
for reuse.
[0020] It is yet another object of the present invention to provide
a trocar in which the upper housing can be quickly disassembled
from the main housing while in use to allow for unobstructed access
through the trocar to the body cavity.
[0021] An additional object of the present invention is to provide
a means by which the trocar blade or cutting tip can be easily
replaced after each surgical procedure thus providing a sharp
cutting edge for each surgical use and also minimizing medical
waste.
[0022] These and other objects are met by Applicants' invention of
a safety shielded, reusable trocar consisting of a trocar cannula
subassembly, a safety shield control mechanism, and a separate
obturator subassembly. The trocar cannula subassembly includes an
outer cannula attached to a main housing having a central bore in
which a spring biased, inner cannula is slidably and removably
inserted, and an upper housing, removably secured to the main
housing, having a central bore which is aligned longitudinally with
the bore of the main housing and in which sealing means is
removably secured.
[0023] The obturator subassembly includes an elongated obturator
having a replaceable and rotatable knife, an elongated shaft, an
arcuate shaped cap, and which extends through the upper housing,
sealing means, main housing, inner cannula, and outer cannula.
[0024] The safety shield control mechanism, located in the main
housing and removably engaged with the inner cannula, allows for
positive and easily verifiable engagement and disengagement of the
inner cannula as a safety shield for the obturator knife. When the
trocar cannula subassembly and safety control mechanism are coupled
proper operation of the safety shield can be verified without the
obturator subassembly being inserted in the inner cannula.
[0025] In operation, the obturator subassembly, upper housing, and
sealing means can be completely removed from the trocar assembly to
allow unobstructed access through the inner cannula to the
patient's internal cavity for removal of specimens or insertion of
equipment. After use, the entire trocar assembly can be easily
disassembled for cleaning, sterilization, and reuse.
[0026] The foregoing will become apparent from the following
detailed description of a preferred embodiment with reference to
the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of the present invention.
[0028] FIG. 2 is a cross sectional view of the present invention
with the safety shield extended.
[0029] FIG. 3 is a cross sectional view of the present invention
with the safety shield partially retracted.
[0030] FIG. 4 is a cut-away sectional view of the present invention
showing the trigger in the safe position.
[0031] FIG. 5 is a cut-away sectional view of the present invention
showing the trigger in the armed position.
[0032] FIG. 6 is a cross sectional view of the present invention
taken along line 6--6 of FIG. 4.
[0033] FIG. 7 is a cross sectional view of the present invention
taken along line 7--7 of FIG.
[0034] FIG. 8 is an exploded view of the present invention.
[0035] FIG. 9 is a cross sectional view of the alternative
embodiment shown in FIG. 11 with the safety shield extended.
[0036] FIG. 10 is a cross sectional view of the alternative
embodiment shown in FIG. 11 with the safety shield partially
retracted.
[0037] FIG. 11 is an exploded view of an alternative embodiment of
the present invention.
[0038] FIG. 12 is an exploded view of the trigger mechanism of the
alternative embodiment shown in FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0039] Referring now to the drawings, FIGS. 1-8 illustrate a first
embodiment of a safety shielded, reusable trocar generally
designated (10) consisting of a trocar cannula subassembly (20), a
safety shield control mechanism (80), and a separate obturator
subassembly (60). The three subassemblies are interfitting, but are
designed to be easily disassembled for easy cleaning and
sterilizing. To facilitate the reusable features of the trocar
(10), it is preferably made from a durable and strong material
which can be cleaned and sterilized, such as surgical stainless
steel, acetal, polysulfone, or any high temperature thermoplastic.
However, any material is acceptable as long as it may be sterilized
by gas, autoclave, cold sterilization, and the like.
[0040] Referring to FIG. 8, the trocar cannula subassembly (20)
includes an outer cannula (22) attached to a main housing (24). The
outer cannula (22) may be attached to the main housing (24) in a
variety of different methods including the outer cannula (22) being
pressed on to the main housing (24) or it may be machined out of
the same piece of metal as the main housing (24). The outer cannula
(22) and main housing (24) align to have a central axial bore (26)
for receiving the inner cannula (30) and the obturator subassembly
(60). The central axial bore (26) is larger in the main housing
(24) than in the outer cannula (22). Main housing (24) has
rectangular recesses (28) to facilitate gripping the trocar with
the fingers and for quickly locating the safety shield control
mechanism (80).
[0041] The inner cannula (30) is a tube adapted to be slidably
inserted into outer cannula (22) and main housing (24) and serves
as a safety shield for the obturator subassembly (60). The aft end
of the inner cannula (30) has a slider (32) attached which is
adapted to allow smooth sliding of the inner cannula (30) in the
larger central axial bore of the main housing (24). The slider (32)
also serves as a stop to prevent inner cannula (30) from sliding
completely through main housing (24). The rear end of slider (32)
has an elongated key (34). The inner side of main housing (24) has
a keyway (not shown) in which key (34) rides to permit axial
movement without rotation of the inner cannula (30) relative to the
outer cannula (22) and main housing (24).
[0042] As shown in FIGS. 2 and 8, upper housing (38) is removably
secured to main housing (24). Upper housing (38) has a lower tube
(42) with a central axial bore (40) adapted to receive the rear end
of inner cannula (30). A spring (44) sits around the rear end of
the inner cannula (30) and lower tube (42) with its ends seated
against the bottom of upper housing (38) and the top of slider
(32). Spring (42) biases inner cannula (30) in the extended
position. The bottom of lower tube (42) serves as a stop to limit
the rearward axial movement of inner cannula (30) relative to main
housing (24).
[0043] Upper housing (38) houses removable sealing means including
a removable, upper wiper seal (46) and a removable flapper valve
seal (48). The seals are preferably made of durable silicon rubber
and plastic which can be sterilized. Wiper seal (46) has a central
opening which is approximately equal to the outside diameter of
obturator. The primary function of wiper seal (46) is to insure a
tight seal when the stem or shaft of obturator or other instrument
shafts are inserted through upper housing (38). Flapper valve (48)
acts as a closure means when obturator or other instrument is
withdrawn and separated from the trocar cannula subassembly (20).
Sealing means retainer (50) is removably attached to upper housing
(38) and serves as a keeper of the seals to prevent them from
falling out of upper housing (38). Sealing means retainer (50) has
a central bore longitudinally aligned with the central bore of
inner cannula (30) for receiving the shaft of obturator or other
instrument.
[0044] The obturator subassembly (60) includes a pyramidal-shaped
knife (62), an elongated stem or shaft (64), an arcuate shaped cap
(66). Obturator (60) is adapted to extend and move longitudinally
through upper housing (38), main housing (24), outer cannula (22),
and inner cannula (30). Inner cannula (30) serves as a safety
shield for the knife (62) portion of obturator (60). Obturator (60)
may be easily removed from the trocar cannula subassembly (20).
[0045] The operation of the inner cannula (30) is controlled by the
safety shield control mechanism (80) which is removably located in
the main housing (24) and is removably engaged with the inner
cannula (30). Safety shield control mechanism (80) provides visual,
tactile, and aural signals to the operator allowing for positive
and easily verifiable engagement and disengagement of the inner
cannula (30) as a safety shield for the obturator knife (62). When
the trocar cannula subassembly (20) and safety shield control
mechanism (80) are coupled, proper operation of the safety shield
can be verified without the obturator subassembly (60) being
inserted in the inner cannula (30).
[0046] As shown in FIGS. 2 through 7, the safety shield control
mechanism (80) includes a trigger pin (82), trigger spring (84),
and red pin (86) which extend perpendicularly through a chamber in
the main housing (24). Red pin (86) is removably secured to main
housing (24). The ends of trigger spring (84) are seated against
the inner face of red pin (86) and the inner face of trigger pin
(82) biasing trigger pin (82) in an extended position.
[0047] Trigger pin (82) has a finger (88) which extends
perpendicularly from main housing (24). Secured to finger (88) is
an offset rectangular member (90) having a keyway (92) and an upper
face (94) and a lower face (96). Upper face (94) has two steps (98
and 100). Secured to offset rectangular member (90) is a circular
housing (102) for receiving trigger spring (84).
[0048] Also part of the safety shield control mechanism (80) are a
latch pin (104), a latch spring (106), and a latch spring retainer
(108) located in the same keyway in main housing (24) as key (34).
Latch pin (104) is adapted to abut key (34) to assist in spring
biasing inner cannula (30) to the extended position.
[0049] In the safe position as shown in FIGS. 2 and 6, trigger pin
(82) is trigger spring (84) biased in the extended position so that
latch pin (104) is demountably located on the first step (98) of
upper face (94) of offset rectangular member (90) and lower face
(96) of offset rectangular member (90) prevents key (34) from
moving axially rearward, thereby keeping the safety shield extended
and locked over obturator knife (62).
[0050] To arm, as shown in FIG. 7, trigger pin (82) is pushed in
perpendicularly to main housing (24) a sufficient distance to allow
latch spring (106) biased latch pin (104) to drop to the second
step (100) of upper face (94). Latch pin (104) while on the second
step (100) abuts the side of the first step (98) and serves as a
latch to prevent perpendicular movement by trigger spring (84)
biased trigger pin (82) and keeps trigger pin (82) in the armed
position. With trigger pin (82) in the armed position, keyway (92)
of offset rectangular member (90) is aligned with key (34) of inner
cannula (30) thereby allowing inner cannula (30) to move
longitudinally inside outer cannula (22). When inner cannula (30)
moves rearward, as shown in FIG. 3, key (34) lifts latch pin (104)
and trigger pin (82) is trigger spring (84) biased outward towards
the safe position. As inner cannula (30) moves forward, key (34)
moves past trigger pin (82) and first step (98) of offset
rectangular member (90) engages latch pin (104), thereby putting
safety shield control mechanism (80) in the safe position.
[0051] The safety shielded, reusable trocar (10) operates and is
used as follows. Before use the trocar (10) will typically be in
the assembled form as shown in FIGS. 1 and 2 with the inner cannula
(30) locked in position as a safety shield for the obturator for
safety purposes and for storage. In this position the knife (62) or
piercing tip is shielded and cannot be damaged by inadvertent
contact with other surfaces. In this locked position, spring (44)
biases inner cannula (30) forward with the forward edges of slider
(32) acting as stops against the lower, inner portion of main
housing (24) to define the forwardmost position of inner cannula
(30). Also in this locked position, lower face (96) of trigger pin
(82) acts as stops against the rearward edges of slider (32) to
define the rearmost position of inner cannula (30) and trigger pin
(82) is in its extended position as shown in FIGS. 4 and 6. Flapper
valve (48) is biased against the shaft (64) of obturator (60) to
frictionally minimize longitudinal movement of obturator (60)
relative to main housing (24). The inner lip of wiper seal (46)
rests snugly against the shaft (64) of obturator (60) and forms a
seal therewith.
[0052] To unlock inner cannula (30) from its safety shield
position, trigger pin (82) is pushed in perpendicularly to main
housing (24), as shown in FIGS. 5 and 7. Latch pin (104) moves to
the second step (100) of trigger pin (82) and keyway (92) of
trigger pin (82) is aligned with key (34) of inner cannula (30).
When latch pin (104) moves to the second step (100) of trigger pin
(82) an audible click is heard by the operator. In this armed
position, inner cannula (30) is free to move longitudinally
rearward until stopped by slider (32) abutting the lower tube (42)
of upper housing (38).
[0053] In surgical use, the trocar (10) is used in conjunction with
insufflatory techniques wherein a needle type instrument first
punctures the skin in a desired body cavity region. Usually, the
needle house a stylet or the like that introduces a gas like carbon
dioxide from a pressurized container into the body cavity. After
the cavity has been inflated, a small incision may be made in the
skin at the desired body cavity location. The trocar (10) is put in
its armed position. The trocar (10) is gripped firmly with the cap
(66) of the obturator (60) against the palm of the surgeon's hand.
The safety shield portion of the inner cannula (30) is placed
against the incision in the skin and firm pressure is exerted
against the skin. The pressure causes the inner cannula (30) to be
pushed rearwardly against spring (44) to its retracted position as
shown in FIG. 3, thereby exposing the knife (62) of the obturator,
and key (34) lifts latch pin (104) from the second step (100) of
trigger pin (82). The tip of the knife (62) enters the incision and
underlying tissue with continued pressure.
[0054] Once the knife (62) has penetrated tissue and has entered
the cavity, the force against the front end of the inner cannula
(30) ceases and the inner cannula (30) is automatically moved
longitudinally back to its extended position through the action of
spring (44). As inner cannula (30) moves forward, key (34) moves
past trigger pin (82) and first step (98) of offset rectangular
member (90) engages latch pin (104), thereby putting safety shield
control mechanism (80) in the safe and locked position.
[0055] The obturator subassembly (60) may be withdrawn from the
trocar cannula subassembly (20) once the cavity has been
penetrated. During withdrawal, once the tip of the obturator (60)
clears the opening in wiper seal (46), flapper valve (48) will bias
the flapper to a sealed position. Air pressure within the body
cavity is thus maintained. Although not shown, main housing (24)
may include a stopcock port into which the nozzle of a stopcock
could be inserted to pass additional insufflating gas into the
cavity.
[0056] The trocar will normally be inserted into the body cavity
until main housing (24) abuts the skin. After the obturator
subassembly (60) has been separated from the trocar cannula
subassembly (20), surgical instruments may be inserted into the
body cavity via the central bore (26) of trocar cannula subassembly
(20) to view internal tissues, perform operations thereon, or drain
bodily fluids.
[0057] If the surgeon desires obstructed access to the body cavity
for better viewing or to take a tissue sample, upper housing (38)
may be removed from main housing (24). By removing upper housing
(38), the wiper seal (46), flapper seal, and seal retainer (50) are
all removed as a single unit. The trocar cannula subassembly (20)
then provides unobstructed access to the body cavity to permit
removal of specimens and to deflate the cavity.
[0058] After use, the entire trocar (10) can be easily disassembled
for cleaning, sterilization, and ready for reuse. Sterilization can
be by any standard sterilization technique.
[0059] An alternative embodiment of the present invention is
illustrated in FIGS. 9-12. Although the function and operation of
the safety'shielded, reusable trocar are the same, there are slight
changes to each subassembly unit.
[0060] The trocar cannula subassembly (220) includes an inner
cannula (230) having a slider (232) located flush with the rearmost
end of the inner cannula (230). A pair of diametrically opposed
axially elongated keys (234) are attached to slider (232). The
interior of main housing (224) has complementary keyways (not
shown) for receiving keys (234) and allowing longitudinal movement
of inner cannula (230) without any rotational movement of inner
cannula (230) relative to main housing (224) and outer cannula
(222). A pair of diametrically opposed latch spring mechanisms are
removably located in keyways. Latch spring mechanisms include a
latch pin (304), latch spring (306), and a latch spring retainer
(308). Latch spring mechanisms are adapted to abut keys (234) to
spring bias inner cannula (230) to the extended position. The
interaction between the latch spring mechanism, trigger pin (282),
and keys (234) is as described above for the first embodiment of
the present invention.
[0061] Upper housing (238) has a bevelled interior surface (239) to
house sealing means such as a flapper valve (248) and wiper valve
(246). The edges of flapper valve (248) are complementarily
bevelled so that the sealing means can only be inserted with
flapper valve (248) closest to inner cannula (230). If the sealing
means would be reversed, the sealing means would not fit into upper
housing (238). Sealing means are kept in place by a sealing means
retainer (250) having a handle (252) to provide easy removable
securing to upper housing (238). Upper housing (238) is removably
engaged between a lock ring (254) which couples to main housing
(224), as shown in FIGS. 9 and 10.
[0062] The obturator subassembly (260) in this embodiment has a cap
(266) secured to a shaft (264). To reduce the overall weight of the
trocar, the shaft (264) may be made of a lightweight and durable
material such as aluminum. Secured to the opposite end of shaft
(264) is a capture fitting (268) for receiving the rounded end
(272) of the knife (262). The knife (262) made be made of stainless
steel or alternatively, to further reduce the overall weight, the
knife (262) made be made of high temperature thermoplastic. This
also gives the additional advantage of making the knife (262)
easily replaceable and interchangeable to ensure that the knife is
always sharp.
[0063] The knife (262) is rotatably and removably secured to the
shaft (264) by means of a capture fitting (268) and capture nut
(270) arrangement. As best seen in FIG. 11, capture fitting (268)
and capture nut (270) are aligned to form a opening (271) for
receiving the rounded end of the knife (262). The knife (262) is
inserted sideways through opening (271). The capture nut (270) is
then rotated at least thirty degrees to rotatably lock knife (262)
to the shaft (264), as shown in FIG. 9.
[0064] The safety shield control mechanism (280) operates in the
same manner as described above. However, the trigger pin has been
modified as shown in FIGS. 11 and 12. The trigger pin (282) is now
designed to move in and out of both sides of the main housing
(224), much like a safety on a rifle. In the armed position, the
red pin (286) protrudes from the main housing (224) and may be
painted the color red. In the safe position, the trigger pin (282)
protrudes from the main housing (224) and may be colored green or
black. Additionally, the offset rectangular member (290) has been
modified for the upper face (294) to have an arcuate shaped second
step (300) and the lower face has an angled keyway (292) with a
bevelled side surface (293). The bevelled side surface (293) allows
for smoother pickup and dropping of the latch pin (304).
[0065] In operation of the alternative embodiment, the steps are
the same as previously described. During insertion of the trocar,
the knife (262) is rotatable. This facilitates a smooth incision
through the skin as the rotatable knife (262) rotates to counter
any rotation of the trocar by the surgeon while applying pressure
to the skin.
[0066] Although the invention has been described with reference to
specific embodiments, this description is not meant to be construed
in a limited sense. Various modifications of the disclosed
embodiments, as well as alternative embodiments of the inventions
will become apparent to persons skilled in the art upon the
reference to the description of the invention. It is, therefore,
contemplated that the appended claims will cover such modifications
that fall within the scope of the invention.
* * * * *