Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02493157 1994-04-19
SURGICAL STAPLER
This application is a divisional application of Canadian patent application
2,121,650, filed April 19, 1994.
FIELD OF THE INVENT10N
The present invention relates to surgical staplers and, more particularly to
surgical
staplers for use in endoscopic and iaparoscopic procedures.
DISCUSSION OF THE PRIOR ART
Laparoscopic and endoscopic surgical procedures are minimally invasive
procedures in which operations are carried out within the body by means of
elongated instruments inserted through small entrance openings in the body.
The
initial opening in the body tissue to allow passage of the endoscopic or
laparoscopic instruments to the interior of the body may be a natural
passageway
of the body, or it can be created by a tissue piercing instrument such as a
trocar.
With the aid of a cannula assembly inserted into the opening, laparoscopic or
endoscopic instrumentation may then be used to perform desired surgical
procedures.
Laparoscopic and endoscopic surgical procedures generally require that any
instrumentation inserted in the body be sealed, i.e. provisions must be made
to
ensure that gases do not enter or exit the body through the instrument or the
entrance incision so that the surgical region of the body, e.g, the
peritoneum, may
be insufflated. Mechanical actuation of such instruments is for the most part
constrained to the movement of the various components along a longitudinal
axis
with means provided to convert longitudinal movement to lateral movement where
necessary. Because the endoscopic or laparoscopic tubes, instrumentation, and
any required punctures or incisions are relatively narrow, endoscopic or
laparoscopic surgery is less invasive and causes much less trauma to the
patient
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as compared to procedures in which the surgeon is required to cut open large
areas of body tissue.
Surgical fasteners or staples are often used to join body tissue during
laparoscopic
and endoscopic procedures. Such fasteners can have a pair of legs joined by a
backspan and are typically set into the body by means of an elongated
instrument
which crimps the fastener legs to secure the fastener and tissue.
Various types of stapling instruments have been known for fixing staples to
body
tissue. Generally, the staples have been applied by using instruments having
an
anvil and an ejector mechanism for driving the legs of a staple through the
tissue
and against the anvil for deforming the legs into a "B" shape or the like. An
example of such a stapler having an anvil is disclosed in U.S. Patent No.
4,665,916. An example of a surgical stapler having an anvil and adapted for
endoscopic use is disclosed in U.S. Patent No. 5,040,715. Although these and
other various types of instruments are useful for driving the legs of the
staple
through tissue, there are times when it is not desirable, necessary or
practical to
drive the legs of the staple through the body tissue in order to affix a
staple. For
example, when applying a purse string to tissue, as in an end to end
anastomosis
procedure, it is not desirable or necessary to staple through tissue, but to
affix the
staples to the tissue.
In cases where a purse string is to be applied to a tubular section of tissue,
known
stapling instruments have been rather cumbersome and complex in order to
provide an anvil against which the staples can be deformed. See, for example,
U.S. Patent No. 4,749,114 and 4,773,420. An anvilless surgical stapler for use
in
open surgery and a method of affixing a staple to tissue without completely
piercing the tissue is disclosed in U.S. Patent No. 4,821, 939. While this
anvilless
stapler has found success in applying purse strings in open surgery, such a
stapler
is not properly configured and dimensioned to be used in endoscopic or
laparoscopic procedures.
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Accordingly, there is a need for an endoscopic surgical stapler adapted for
use in
confined areas. There is also a need for an anvilless surgical stapler capable
of
endoscopically applying staples to body tissue. There is also a need for an
endoscopic surgical stapler for applying a purse string to body tissue.
Additionally,
there is a need for an endoscopic surgical stapling instrument capable of
applying
a purse string to body tissue, wherein the staples secure the string element
to
body tissue without piercing the tissue with the legs of the staples. There is
also a
need for surgical staplers, adapted for endoscopic or open surgery, that are
capable of joining tubular organs.
SUMMARY OF THE INVENTION
The present invention provides a novel anvifless endoscopic or laparoscopic
surgical instrument having an endoscopic portion with proximal and distal end
portions. fn one embodiment, the instrument has a pair of jaws positioned at
the
distal end portion, each adapted to carry a fastener cartridge. The fastener
cartridge has a tissue contacting surface and a plurality of fasteners
slidably
disposed therein. Both the endoscopic portion and the jaws are adapted tv be
insertable into a cannula. Each fastener has a pair of deformable legs joined
by a
backspan and are disposed within the ejected from the cartridge in a manner
substantially similar to that disclosed in U.S. Patent Nos. 4,821,939 and
5,158,567. Means for ejecting the fasteners may include at least one fastener
firing cam member for contacting pushers disposed within the cartridge, the
pushers being designed to contact and eject the fasteners from the cartridge.
Means remote from the distal portion of the endoscopic instrument are adapted
to
cause the firing cam member to be drawn across the pusher members. This
operation may be accomplished, for example, by having a slidable member
disposed at the proximal end of the instrument which is attached to the cam
member by means of a wire, a rod, or the like.
The purse string suture portion can be positioned adjacent the jaws and/or the
tissue contacting surface of the fastener cartridge such that upon ejection of
the
fasteners, the suture will be held between the fastener backspans and tissue.
A
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handle assembly having a stationary handle and a movable handle is also
provided to open and close the fastener jaws.
In operation, a cannula is inserted into the abdominal cavity. The surgical
instrument of the present invention is inserted through the cannula with the
jaws in
a substantially closed position. After insertion, the movable handle is moved
away
from the stationary handle thereby causing the jaws at the distal end of the
instrument to open. The organ or tissue to which the purse string is to be
applied
is then oriented between the jaws. The movable handle is then brought into
approximation with the stationary handle to cause the jaws to close about the
organ or tissue. The purse string may then be applied by causing the fasteners
to
be ejected from the jaws, such as by causing a cam member to sequentially
eject
the fasteners from the cartridge, which thereby secures the suture in a purse
string
configuration about the organ or tissue. After firing, the jaws may then be
opened
to release the tissue or organ by moving the movable handle away from the
stationary handle. After re-closing the jaws, the instrument may be withdrawn
from the cannula. Finally, the purse string may be tightened about the organ
or
tissue by manipulating the suture as desired.
fn accordance with another aspect of the present invention, a stent is used to
aid
in the manipulation and/or approximation of tubular organs. The stent can be
of a
generally rectangular shape and can either be expandable or fragmentable.
Preferably, corners of the stent have angular projections which facilitate
placement
and retention of tubular organ sections.
Another aspect of the invention includes a single s hot stapler which provides
the
user with a means for applying a single staple to aid in the anastomosis of
tubular
organs. The single shot stapler includes a stationary housing, a movable
housing
and two staple deforming members which approximate in response to relative
movement behnreen the two housings.
According to another feature of the invention, a surgical staple applier is
provided
which is adapted to simultaneously fire a plurality of staples from a pair of
jaws.
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The stapler can be adapted for open surgery or endoscopic surgery.
Furthermore,
the stapler may incorporate various forms of stent embodiments to aid in the
approximation and manipulation of tubular organs.
In one embodiment of the present invention there is provided a surgical
instrument
comprising: a) an elongated portion having proximal and distal end portions
and a
longitudinal axis; b) a pair of jaws extending from the distal end portion, at
least one
of the jaws being pivotable relative to the elongated longitudinal axis
between open
and closed positions wherein when at least one of the jaws is in the closed
position,
at least one jaw is in substantial parallel alignment with the longitudinal
axis; and c) a
plurality of fasteners disposed within each of the jaws.
The above embodiment preferably further comprises: d) fastener carrying means
disposed within at least one jaw of the pair of jaws for carrying a plurality
of
fasteners, the fasteners each having a pair of legs joined by a backspan
wherein the
backspan is in substantial perpendicular alignment to the elongated
longitudinal axis;
and e) means for ejecting the fasteners from at least one jaw.
Desirably, the fastener carrying means comprises a plurality of fastener
receiving
slots, the fastener carrying means comprises at least one cartridge having a
tissue
contacting surface and a plurality of fastener receiving slots, there further
comprises
anvilless means for deforming the fastener legs from an open configuration to
a
closed configuration when the fasteners are ejected from at least one jaw, and
the
anvilless deforming means comprises a pair of inwardly directed lips disposed
at one
end of each of the fastener receiving slots.
It is preferable the above embodiment further comprises at least one suture at
least
partially positioned adjacent at least one jaw, there further comprises at
least one
suture at least partially positioned adjacent the tissue contacting surface,
and when
at least one jaw is in the closed position and the fasteners are slidably
ejected
therefrom, the fasteners are ejected toward the elongated longitudinal axis.
Desirably, there further comprises at least one suture at least partially
disposed
adjacent at least one jaw, there further comprises means for pivoting at least
one jaw
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between the open and closed positions, the jaw pivoting means comprises a
handle
assembly disposed at the proximal end .portion, the handle assembly has a
stationary handle and a movable handle, and at least one jaw comprises at
least one
jaw camming slot and wherein the jaw pivoting means further comprises at least
one
jaw camming pin slidable within at least one camming slot.
Preferably, there further comprises a rod having distal and proximal end
portions, the
rod extending at least partially through the elongated portion, wherein the
distal
portion of the rod is mechanically connected to at least one jaw camming pin
and the
proximal portion of the rod is mechanically connected to the movable handle.
It is desirable there further comprises means for articulating at least one
jaw relative
to the elongated longitudinal axis, at least one jaw defining a longitudinal
jaw axis
which is substantially parallel to the elongated longitudinal axis when the
instrument
is in an unarticulated position, when the instrument is articulated, the
longitudinal jaw
axis is positioned at an angle with respect to the elongated longitudinal axis
and the
fastener backspan remains in substantial perpendicular alignment to the
longitudinal
jaw axis, the articulating means comprises a movable rod at least partially
disposed
within the elongate portion, both the elongated portion and the jaws are
adapted to
be insertable into a cannula and the means for ejecting the fasteners includes
at
least one remote firing mechanism, and each of the fasteners comprise a pair
of legs
joined by the backspan.
Desirably, when the pair of jaws are both in substantial parallel alignment
with the
elongated longitudinal axis, the fastener legs are oriented toward the
elongated
longitudinal axis, the fastener backspan is oriented substantially
perpendicular to the
elongated longitudinal axis, there further comprises anvilless means for
deforming
the fastener legs, there further comprises jaw pivoting means for pivoting the
pair of
jaws between open and closed positions, the jaw pivoting means comprises a
handle
assembly disposed at the proximal end portion, and the handle assembly
comprises
a stationary handle and a movable handle wherein movement of the movable
handle
causes the jaws to pivot between the open and closed positions.
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Moreover, it is preferable in the above embodiments there further includes a
stent
extending from the elongated portion distal end, the stent comprising a first
member
and a second member each having proximal and distal ends, wherein the first
and
second members are longitudinally slidable relative to each other such that
the
longitudinal distance between the first member distal end and the second
member
proximal end is adjustable, the elongated portion comprises first and second
elongated members, the first elongated member engages the first stent member
and
the second elongated member engages the second stent member, the second
elongated member is longitudinally slidable relative to the first elongated
member,
and there further comprises means disposed in the handle assembly for moving
the
second elongated member.
Preferably, the stent is for use in surgery and comprises a plurality of
interrelating
stent portions, each of the portions having a generally planar portion
integral with a
generally curved portion, the stent portions being arranged such that the
generally
curved portions are aligned along a longitudinal axis and at least one
generally
planar portion is disposed on one side of the stent longitudinal axis and at
least one
of generally planar portion is disposed on the other side of the stent
longitudinal axis,
the planar portions are symmetrical with respect to a plane passing through
the stent
longitudinal axis, the stent is in a sterile condition, the generally curved
portions are
at least partially cylindrical in configuration, and at least one generally
curved portion
has a longitudinal aperture adapted to receive an elongate stent rod
therethrough.
It is desirable that each generally curved portion has a longitudinal aperture
adapted
to receive an elongate stent rod therethrough, the elongate aperture is
rectangular in
configuration, there further comprises an elongate stent rod disposed within
the
longitudinal apertures, the elongate rod is configured and dimensioned to
prevent
rotation of the stent about the stent longitudinal axis, and the elongate rod
is
generally rectangular in cross section.
Further, it is also desirable at least one generally planar portion has a
projection
angled towards the generally curved portion, the projection being disposed in
the
plane passing through the stent longitudinal axis, having an even number of
stent
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CA 02493157 2005-11-25
portions, such as having four stent portions, the stent is at least partially
fabricated
from a bio-absorbable material, and the bio-absorbable material is selected
from the
group comprising glycolide, lactide and polyvinyl alcohol.
In another embodiment of the present invention there is provided a surgical
instrument comprising: a) an elongated portion having proximal and distal end
portions and a longitudinal axis; b) a pair of jaws extending from the distal
end
portion, at least one of the jaws being pivotable relative to the elongated
longitudinal
axis between open and closed positions wherein, when at least one of the jaws
is in
the closed position, at least one jaw is in substantial parallel alignment
with the
longitudinal axis; c) a plurality of fasteners disposed within each of the
jaws; and, d)
a seal positioned within the elongated portion to at least partially obstruct
the
passage of gases therethrough.
Desirably, the elongated portion is generally circular in cross section, the
elongated
portion has an outer diameter of between about 5mm to about 15mm, there
further
comprises means for simultaneously firing the plurality of fasteners from each
of the
jaws, and the simultaneous firing means comprises a pair of staple deforming
bars
disposed within each of the jaws, the staple deforming bars being movable
between
a first position and a second position, wherein movement from the first
position
causes at least partial deformation of the plurality of fasteners.
Preferably, there further comprises means for sequentially firing the
plurality of
fasteners from each of the jaws, the sequential firing means comprises a cam
member slidably disposed within each of the jaws, the cam member being movable
befinreen a first position and a second position, each of the jaws include a
stationary
plate member and a movable plate member, the movable plate member being
longitudinally slidable within the jaw, each of the plate members have a
plurality of
slots passing therethrough, each of the jaws further include a pair of
longitudinally
disposed bars, the bars having projections adapted to pass at least partially
through
the plurality of plate member slots, and movement of the movable plate members
causes each of the bars to move laterally towards each other.
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In yet another embodiment of the present invention there is provided a
surgical
instrument comprising: an elongated portion having proximal and distal end
portions
and a longitudinal axis; a pair of jaws extending generally longitudinally
from the
distal end portion, at least one of the jaws being pivotable relative to the
elongated
longitudinal axis between open and closed positions wherein, when at least one
of
the jaws is in the closed position, at least one of the jaws is in substantial
parallel
alignment with the longitudinal axis; and a plurality of fasteners disposed
within each
jaw, wherein each fastener has a pair of legs joined by a backspan, each
fastener
backspan being oriented substantially perpendicular to the elongated
longitudinal
axis and wherein each fastener is ejected towards the elongated longitudinal
axis
when the instrument is fired.
Desirably, each fastener has a pair of legs joined by the backspan and the
fastener
legs are oriented toward the elongated longitudinal axis when the jaws are in
the
closed position, there further comprises anvilless means for deforming the
fastener
legs, there further comprises means for ejecting the fasteners from each jaw,
and
there further comprises at least one cam member disposed in each jaw for
sequentially ejecting the fasteners from each jaw.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing objects and other features of the invention will become more
readily
apparent and may be understood by referring to the following detailed
description of
illustrative embodiments of the endoscopic or laparoscopic surgical apparatus
for
applying a purse string, taken in conjunction with the accompanying drawings,
in
which:
Figure 1 illustrates a perspective view of a preferred embodiment of the
present
invention.
Figure 2 illustrates an exploded view of the handle assembly of Figure 1.
Figure 3 illustrates an exploded view of the endoscopic and distal portions
assembly of Figure 1.
Figure 4 illustrates a cut away plan view showing the jaws of Figure 1 in an
articulated position.
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Figure 5 illustrates a sectional view taken along lines 5-5
of Figure 4.
Figure 6 illustrates a side elevation cut away of the jaws
of Figure 1 in an open
position.
Figure 7 illustrates the jaws of Figure 6 in a closed position.
Figure illustrates a perspective view of an alternative
8 embodiment of the
present invention.
Figure 9 illustrates a further alternative embodiment of
the present invention.
Figure 10 illustrates the embodiment shown in Figure 9 with
the handle down and
jaws closed.
Figure illustrates the instrument of Figure 10 after actuation
11 of the fastener
firing mechanism.
Figure 12 illustrates a cut away plan view showing jaw articulation
via a push rod.
Figure 13 illustrates a sectional view taken along lines 13-13
of Figure 12.
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Figure 14 illustrates a tubular section of tissue having a purse string
applied
thereto by the instrument of the present invention.
Figure 14a illustrates two joined tubular sections of tissue having different
diameters, the smaller diameter section is cut at an angle to facilitate
joining to the larger diameter section.
Figure 15 illustrates a perspective view of an expandable sent and expandable
stent applicator.
Figure 16 illustrates an exploded view of the stent and applicator of Figure
15.
Figure 17 illustrates tubular organs disposed about an unexpanded stent.
Figure illustrates tubular organs disposed about an
18 expanded stent.
Figure 19 illustrates a perspective view of a single shot
staple applier.
Figure 20 illustrates an exploded view of the single shot
stapler applier of
Figure 19.
Figure 21 illustrates a side plan cut away view of the staple applier of
Figure 19
prior to firing.
Figure 22 illustrates a side plan cut away view of the stapler of Figure 19
after
firing.
Figure 23 illustrates a perspective view of a surgical stapling device of the
present invention.
Figure 24 illustrates a perspective cut away view of the surgical stapler of
Figure 23.
Figure 25 illustrates an exploded view of a stapling assembly in accordance
with one embodiment of the present invention.
Figure 26 illustrates tubular organs being placed on a stent portion of the
surgical stapler of Figure 23.
Figure 27 illustrates the distal end of the surgical stapler of Figure 23
closed
about two tubular organs.
Figure 28 illustrates a cross sectional view of Figure 27 after firing the
staples.
Figure 29 illustrates removal of the surgical stapler from the joined tubular
organ.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now in specific detail to the drawings, in which like reference
numerals
identify similar or identical elements, Figure 1 illustrates a first
embodiment of the
endoscopic or laparoscopic surgical apparatus 10 for applying surgical
fasteners.
Apparatus 10 comprises endoscopic portion 14, handle assembly 12 and fastener
applying assembly 20. Endoscopic portion 14 and assembly 20 are configured
and dimensioned to be inserted into a cannula. Handle assembly 12 is
positioned
at the proximal end of endoscopic portion 14 and is shown with stationary
handle
30 and movable handle 60 in an open position. Handle assembly 12 functions to
open and close assembly 20, which is positioned at the distal end of
endoscopic
portion 14. As shown by arrows A and B, and as will be described in further
detail
below, endoscopic portion 14 can be articulated at articulation joint 16 by
manipulating articulation knob 90. Proximal movement of knob 90 will cause the
distal end of endoscopic portion 14 and assembly 20, shown in phantom, to
deflect
at joint 16 away from the instrument's central axis X-X. Arrows C and D depict
rotational movement of the endoscopic and distal portions of instrument 10
which
can be achieved by rotating knob 76.
Turning to handle assembly 12 with reference to Figure 2, stationary handle
housing 30 is shown in two halves. Halves 30 can be secured together by mating
protrusions 32a with corresponding recesses 32b. When joined, the stationary
housing defines recess 39 wherein proximal plate 38 is longitudinally movable.
Plate 38 includes firing slot 40, pin opening 46, distal slot 42 and center
rod
opening 74. Firing slot 40 permits tongue 41 of firing button 36 to be
slidably
received therein. Tongue 41 is further connected to firing wires 37, the
purpose of
which will be described in greater detail below.
Link 48 serves to connect the proximal end of movable handle 60 with plate 38.
Plate pin 44 is insertable through pin opening 46 in plate 38 and lower pin
opening
50 in link 48. Movable handle pin 54 is insertable through upper pin opening
52 in
link 48 and pin opening 56 in movable handle link connector plate 58. The
distal
end of movable handle 60 is pivotally secured to rear cover tube 68 by handle
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pivot pin 66. Handle pivot pin 66 passes through pivot pin openings 64 in
pivot
plates 62 and pin openings 69 in rear cover tube 68. The distal end of plate
38 is
insertable into rear cover tube 68 and is slidable therein by means of slot 42
through which pin 66 passes. The proximal end of endoscopic portion 14 is
rotatably secured to rear cover tube 68 and inner rod 70 (shown in phantom) of
endoscopic portion 14 has axial groove 72 which is insertable into slot 74 of
plate
38. When assembled, inner rod 70 will be disposed distal of pin 66.
In operation, when movable handle 60 is urged towards stationary handle 30,
the
distal end of movable handle 60 pivots about pin 66, causing link 48 to urge
plate
38 in a distal direction. When closed, movable handle 60 remains adjacent
stationary handle 30 due to over centering of pin 54. Distal movement of plate
38,
causes inner rod 70 to move distally as well. Spring 78, disposed adjacent
plate
38 is secured to stationary handle protrusion 81 (see Fig. 9) by distal spring
hook
80 and secured to cam pin 44 by proximal spring hook 82. Spring 78 serves to
provide resistance to the closing of the movable handle and to facilitate the
opening of the movable handle.
Turning to the endoscopic and distal portions of the surgical device of the
present
invention, with reference to Figures 1, 2 and 3, the endoscopic portion
includes
cover tube 102 (shown in two halves), inner rod 70, firing wires 37,
articulation rod
96, and optional inner rod sheath 200. Proximal rotation knob 76 has an
irregular
outer surface to facilitate grasping and serves to allow the surgeon to rotate
cover
tube 102. Rotation knob 76 has inner circular disks 106 and 108 which define
circular channel 110. Flange 112 of cover tube 68 is received within channel
110
in a manner which permits cover tube 102 to rotate with respect to rear cover
tube
68 and, therefore, handle assembly 12.
The articulating mechanism includes articulating knob 90, rod 96 and
articulating
joint 16. Rod 96 has distal end 100 and proximal hook 98. Distal end 100 of
articulating rod 96 is secured to articulating portion 116 by pin 101. The
proximal
end of rod 96 terminates in hook 98 which passes through slot 104 of lower
tube
102 and is received within recess 94 of articulating knob 90. Articulating
knob 90
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is assembled about tube 102 by joining protrusions 91 and corresponding
recesses 92. Hook 98, secured to the articulating knob at recess 94 and being
slidable within slot 104 of tube 102, permits movement of the articulating
knob
along longitudinal axis X-X of endoscopic portion 14. Articulating portion 116
of
endoscopic portion 14 is joined to cover tube 102 at joint 16. Opposing pins
120
are received within pin openings 118 of articulating portion 116 and pin
openings
119 formed in articulating joint members 114. By moving articulating knob 90
longitudinally, articulating rod 96 is also moved longitudinally, thereby
causing
articulating portion 116 to pivot about pins 120 of articulation joint 16 in a
direction
away from the longitudinal axis X-X of endoscopic portion 14.
With reference to Figures 3, 6 and 7, fastener carrying cartridges 125a and
125b
are disposed within jaws 124a and 124b and have tissue contacting surfaces
127a
and 127b. Jaws 124 can be adapted to slidably receive cartridges 125 so as to
provide means for reloading the instrument for multiple firings.
Alternatively, the
fasteners can be disposed directly into the jaws without the use of
cartridges.
Jaws 124 are secured to articulating portion 116 by pin 122. Pin 122 is
received
through pin openings 121 of articulating portion 116, pin openings 132a and
132b
of jaw cam plates 128a and 128b and through pin opening 140 of jaw spacer 136.
Jaw cam pin 134 passes through jaw cam slots 130a and 130b of jaw cam plates
128a and 128b, spacer slot 138 of jaw spacer 136 and pin opening 144 of
articulating jaw cam plate 142. The proximal end of jaw cam plate 142 is
secured
to center rod 70 at recess 71 by pin 73 which passes through plate 142 at pin
opening 75. Cam plate 142 is made of a flexible material to permit
articulation and
enable manipulation of the jaw camming mechanisms while the instrument is
articulated.
Firing wires 37 are also disposed in endoscopic portion 14 and have firing
cams
146a and 146b which are disposed within jaws 124a and 124b, respectively.
Suture 300 is positioned adjacent tissue contacting surfaces 127 and jaws 124
(see Figs. 6 and 7). Operation of the firing mechanism will be discussed in
greater
detail below. Optionally, inner rod sheath 200 can be provided to facilitate
an
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alternate method of rotating the distal end of the instrument (see discussion
of
Figs. 12 and 13 below).
Turning to the jaw manipulation mechanism of the present invention, with
reference to Figures 3, 4, 6 and 7, when the jaws are in the open position,
jaw pin
134 is disposed at the distal end of slots 130a and 130b. In this position,
inner rod
70 is in a forward or distal position and movable handle 60 is in its open
position.
By closing the handle assembly, i.e. moving movable handle 60 toward
stationary
handle 30, inner rod 70 and jaw cam pin 134 are drawn in a proximal direction.
When jaw cam pin 134 travels through jaw cam slots 130a and 130b, jaws 124a
and 124b are caused to pivot about jaw pin 122 and are urged towards each
other. When the instrument is not articulated, the jaws will move towards the
longitudinal axis X-X of the instrument. If the instrument is articulated, the
jaws will
move towards articulated jaw axis X'-X'. As shown in Figure 7, when the jaws
are
fully closed, jaw stops 148a, 148b, 149a and 149b are in contact and tissue
contacting surfaces 127 of cartridges 125 are in substantial parallel
alignment.
An alternative method for closing the jaws is illustrated in Fig. 9. In this
embodiment, articulating cam plate 190 has pin 192 which travels in slot 198
of
jaw 204. Jaw 206 has pin 196 which is configured to travel along slot 194 of
cam
plate 190. When movable handle 60 is urged towards stationary handle 30, inner
rod 70 is drawn in a distal direction, causing cam plate 190 to move distally
as
well. As plate 190 moves distally, pin 192 causes jaw 204 to move towards jaw
206 and slot 194 causes pin 196 on jaw 206 to move jaw 206 towards jaw 204.
When handle 60 is in a fully closed position, jaws 206 and 204 will have moved
into substantial parallel alignment and be ready for firing.
Referring to Figures 4 and 5, articulation is achieved by pulling articulating
knob 90
in a proximal direction (arrow H). This proximal movement causes articulating
rod
96 to pull on articulating portion 116 at pin 101. When articulated, axis X'-
X' of
jaws 124 and articulated portion 116 moves away from axis X-X of the non
articulating endoscopic portion of the instrument. At any jaw position the
distal end
of the instrument can be articulated and the jaws will open and close towards
longitudinal jaw axis X'-X' of the instrument.
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An alternative embodiment of the present invention is illustrated in Figs. 8,
12 and
13. In this embodiment, rotation knob 150 causes the rotation of endoscopic
articulation portion 186 and jaws 124, illustrated by arrows E and F,
respectively,
relative to endoscopic portions 184 and 185. This embodiment includes center
rod
cover sheath 200 (see Fig. 3) which provides means to translate rotation
movement from knob 150 to the distal portion of the instrument. Referring to
Figs.
8 and 13, rotation of knob 150 causes sheath 200 to rotate, further causing
distal
articulating portion 186 and jaws 124 to rotate. Articulating portions 185 and
186
are rotatable with respect to each other by means of rotation joint 202. Both
jaw
cam pin 134 and jaw pivot pin 122 are located in rotatable articulation
section 186.
With sheath 200 secured to the proximal end of section 186, rotational
movement
bypasses the entire endoscopic portion proximal of joint 202. Figures 12 and
13
also show an alternative method of articulation. Here, distal movement of
articulating knob 90 causes articulation rod 96 to push against portion 185,
causing the distal end of the instrument to deflect away from axis X-X.
The firing mechanism of the present invention is best illustrated in Figs. 10
and
11.Once the movable handle 60 and stationary handle 30 are brought in the
closed position, the firing mechanism can be actuated. Firing button 36 can be
drawn in a proximal direction (arrow G) thereby causing firing wires 37 and
attached staple pusher cams 146 to be drawn proximally. Proximal movement of
cams 146 causes staple pushers 208 to sequentially fire staples 210 from the
jaws. Providing separate means for firing staples 210 from each jaw, such as a
firing button secured to each firing wire (not shown), is considered within
the scope
of the invention.
Staples 210 are slidably mounted within the jaws or jaw cartridges and
deformed
without the use of an anvil upon ejection therefrom as disclosed in U.S.
Patent No.
4,821,939. Staples 210 are aligned such that their backspans are in
substantial
perpendicular alignment to the longitudinal axis X-X of the instrument when in
the
unarticulated position. As cams 146 are drawn across pushers 208, staples 210
are ejected towards axis X-X. It will be appreciated that when the instrument
is in
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CA 02493157 1994-04-19
an articulated position, the staple backspans are in substantial perpendicular
alignment to longitudinal axis X'-X' of the articulated jaws and are capable
of being
fired toward that longitudinal axis while articulated.
Referring to Figures 3, 6, 7 and 13, suture 300 has two end portions, a body
portion and is partially disposed adjacent tissue contacting surfaces 127 of
fastener cartridges 125. Suture 300 is held in place by means of jaw stops 148
and 149 in a manner similar to that disclosed in U.S. Patent No. 4,821,939. As
shown in Figures 6 and 7, suture 300 loops back along jaws 124 with the two
end
portions terminating proximal of jaws 124. When applied, suture 30 is secured
between the backspans of fasteners 210 (see Figs. 10 and 11 ) and the tissue
or
organ, such as, for example, intestines or blood vessels 302, to which the
fasteners are applied (see Fig. 14). Any suture placement which allows the
suture
to be secured to body tissue by at least one fastener is considered to be
within the
scope of the present invention.
In operation, the instrument of the present invention is inserted through
cannula
with the handles and jaws in the closed position. Once within the abdominal
cavity, movable handle 60 may be moved away from stationary handle 30, aided
by spring 78, thereby causing center rod 70 to move in a distal direction,
causing
the jaws to open. Using the articulating and rotating mechanisms if desired,
the
organ or tissue to which the purse string is to be applied will be positioned
between the jaws. The jaws may then be closed by bringing movable handle 60
towards stationary handle 30. With the tissue or organ disposed adjacent
tissue
contacting surfaces 125, the surgeon may then slide firing button 36
proximally to
eject the staples into the tissue, thereby securing the suture. After firing,
the
surgeon will then open the handles and jaws as previously described to release
the organ or tissue. Finally, by closing the handles and jaws, the surgeon may
remove the instrument through the cannula.
In an alternative embodiment of performing an end to end anastomosis, with
reference to Figs. 15-18 and 21-25, a stent is provided to facilitate
approximation
of tubular organs andlor to facilitate the joining of tubular organs by means
of
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CA 02493157 1994-04-19
fasteners. In one embodiment, with reference to Figs. 15-18, an expandable
stent
450 is disposed at the distal end of elongate member 404. Generally,
expandable
stent 450 has first side 455 and second side 457 which are transverse to
proximal
surface 451 and distal surface 453.
With reference to Fig. 16, expandable stent 450 includes a stationary member
452
and a movable member 454. Stationary member 452 includes opposing, raised
side walls 456 and 458 and raised distal wall 460. Stationary cover plate 462
is
secured to stationary stent member 452 by pins 464 which pass through holes
466
in cover plate 462 and corresponding holes (not shown) in stationary stent
member 452. Movable stent member 454 is received between cover plate 462
and stationary stent member 452 and slidable therebetween.
Elongate member 404 has two adjacent portions 406 and 408. Stationary
elongate portion 406 is received in slot 468 of cover plate 462 and is secured
to
stationary stent member 452 by means of screw 470 which passes through screw
holes 472, 474, and 476. Movable elongate member 408 has T-shaped portion
412 at its distal end and right angle projection 410 at its proximal end. T-
shaped
portion 412 is configured and dimensioned to be received in recess 480 in the
proximal end of movable stent 454. Both elongate members 406 and 408 are
received in slots 482 and 484, respectively, in handle portion 402. Stationary
elongate member 406 is secured to hemi portion 402A by means of screws 486
while movable elongate portion 408 is disposed in handle portion 402 in slots
484
and wide slot 486. Slider knob 494 further secures elongate portion 408 by
receiving a portion of right angle portion 410 therein. As shown, screws 488
secure hemi portion 402A to hemi portion to 402B by passing through slots 490
and 492.
Returning to the stent portion, preferably both movable stent portion 454 and
stationary stent portion 452 have inwardly facing projections 496. These
projections facilitate placement of a tubular organ over the stent as will be
described in greater detail below. Additionally, optional stem projection 498
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CA 02493157 1994-04-19
protrudes from the distal portion of stationary stent 452, the function of
which is
also described below.
In operation, with reference to Figs. 17 and 18, stent applicating device 400
is
shown with two portions of tubular organs disposed over stent 450. In Fig. 17,
stent 450 is in its collapsed position. In this state, movable elongate member
408
is in its distal most position, which facilitates placement of tubular organs
500 over
projections 496. When placing the organs over sides 455 and 457 of stent 450,
projection 498 inhibits over placement of the organs, thereby aiding in
retaining
each organ on its respective side of the stent. After organs 500 are placed on
each side of the stent, knob 494 is moved proximally (arrow I) to slide
movable
elongate member 408 relative to stationary member 406, thereby causing movable
stent portions 454 to slide proximally relative to stationary stent member
452. As
shown, slot 478 in movable stent member 454 permits movement of movable stent
454 relative to screw 470. Slot 478 can have inwardly projecting serrations
479 to
facilitate incremental expansion of stent 450.
Upon expansion of stent 450, tubular organs 500 are caused to stretch and
flatten
out along the longitudinal span of stent. Projections 496 facilitate in
preventing
organs 500 from slipping off stent 450. Also, upon expansion of stent 450,
edges
502 of each organ tend to move toward the longitudinal axis of the instrument,
thereby decreasing the distance between the two organs to be joined. Once the
tubular organs are disposed about a stent in this manner, various methods of
joining the organs can be employed which will be described hereinbelow.
A single shot staple applier is illustrated in Figs. 19-22. Stapler 800
includes
movable housing 802 having elongate portions 804 and 806 extending distally
from vertical wall 808. Elongate members 804 and 806 define slot 805
therebetween in which stationary housing 820 is slidably received. Stationary
housing 820 includes proximal end 822, which is generally configured in a T-
shape
to facilitate gripping by the user. The distal portion of housing 820 includes
elongate members 824 and 826 which define slot 825 therebetween. Staple
deforming assemblies 832 and 834 are received in slot 825 and are configured
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CA 02493157 1994-04-19
and dimensioned to reciprocate laterally therein. The staple deforming
assemblies
include flat portions 833 and 835 having slanted slots 836 and 838,
respectively.
Means for engaging a staple are shown in Fig. 20, wherein staple engaging
member 842 generally projects upward from the distal end of flat portion 835
while
engaging member 840 projects generally downward from flat portion 833. This
upward/downward configuration permits flat portions 833 and 835 to overlap
during use while allowing staple engaging members 840 and 842 to approximate
in a common plane. The staple engaging members further include staple
receiving and deforming slots 844 and 846 which are configured and dimensioned
to receive staple 850. Preferably, each staple deforming slot has a groove 848
to
facilitate placement and control the staple during use.
When assembled, stationary housing 820 is slidably received in slot 805 of
movable housing 802. Spring 812 is disposed between vertical wall 808 of
movable housing 802 and passes through orifice 830 to enter bore 831 in the
proximal end 822 of stationary housing 820. Pin 816 passes through orifices
814
in elongate members 805 and 806, slot 828 in elongate member 824 (and a
corresponding slot in elongate member 826 - not shown) and slanted slots 836
and 838. A staple can be loaded between engaging members 840 and 842 when
pin 816 and movable housing 802 are proximally positioned (Fig. 21 ) with
respect
to stationary housing 820.
With reference to Figs. 21 and 22, single shot stapler 800 is shown applying a
staple across two tubular organs. With tubular organs 852 and 854 properly
approximated, i.e., by hand manipulation or through the use of a stent (see
stents
in Figs. 17 and 25) the distal end of the staple applier 800 is brought in to
contact
with both ends of the tubular organ. By sliding movable housing 802 relative
to
stationary housing 820, pin 816 is caused to travel in a distal direction
through
slots 828, 836 and 838. As shown in Fig. 22, this movement of pin 816 causes
staple deforming assemblies 832 and 834 to overlap and further cause staple
engaging members 840 and 842 to close staple 850 into a pretzel-shape. After
firing, pin 816 can be moved in a proximal direction to cause staple engaging
members 840 and 842 to release staple 850, leaving the ends of tubular organs
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CA 02493157 1994-04-19
852 and 854 joined. Subsequent application of additional staples can complete
the anastomosis of the tubular organs. While stapler 800 can be used to
perform
an anastomosis without further instrumentation, preferably a stent is used to
facilitate orientation of the tubular organs.
An alternative embodiment of a stent member is shown in Figs. 23-29. Turning
to
Fig. 25, fragmentable stent 600 includes a plurality of interrelating stent
portions
601, 602, 603 and 604. Each of these stent portions have a generally planar
portion 606 integral with a generally curved portion 608. The generally curved
portions are arranged such that they are aligned along longitudinal axis X-X
of the
instrument and such that generally planar portions 606 are disposed on either
side
of longitudinal axis X-X. Stent rod 610 passes through apertures 612 of curved
portions 608 of each stent portion. Stent rod 610 is designed to engage the
stent
portions so as to prevent their rotation relative to axis X-X and to at least
partially
maintain and control the longitudinal orientation of the scent with respect to
the
stapling portion of the instrument.
Preferably, stent 600 includes projections 614 which are angled toward curved
stent portions 608 and generally lie in a plane which cuts through axis X-X.
Projection 614 function in a manner similar to projections 496 in expandable
stent
embodiment 450 (see e.g., Fig. 15). Stent portions 601-604 are designed to be
freely movable from each other when stent rod 610 is removed from orifices
612.
The purpose of this configuration is described in greater detail, below, in
conjunction with Fig. 29. It is understood that several variations of stent
600 are
considered within the slope of the present invention. Rod 610, for example,
need
not pass through all stent members. Furthermore, for example, stent 600 could
be
entirety or partially planar, i.e., curved portions 608 are preferred but
optional.
With reference to Figs. 23-29, a novel surgical stapler 700 is shown. Stapler
700
includes endoscopic portion 702 having proximal and distal ends, distal
stapling
portion 704 and proximal handle portion 706. Endoscopic portion 702 and
stapling
portion 704 are configured and dimensioned to be insertable into a cannula,
with
the endoscopic portion preferably having a substantially circular outer
diameter of
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CA 02493157 1994-04-19
between about 5mm and 15mm. Endoscopic portion 702 includes outer tube 708,
inner tube 710 and stent rod 712 passing therethrough. Stent rod 712 and inner
tube 710 are manipulable by knob 714 and lever 716 respectively. If surgical
stapler 700 is used during endoscopic or laparoscopic procedures where
positive
gas pressure exists in a body cavity, a seal 703 is preferably provided within
endoscopic portion 702 to prevent or reduce the flow of gases therethrough. As
is
known in the art, a seal 703 is provided with suitable orifice to permit
passage of
structures through endoscopic portion 702. Suitable seal materials include
synthetic foams and rubbers.
With reference to Fig. 23, stapling portion 704 is disposed at the distal end
of
endoscopic portion 702 and includes jaws 720A and 720B shown in the open
position. With the jaws open, stent rod knob 714 is slidable relative to the
longitudinal axis of the instrument to manipulate the orientation of stent 600
relative to distal jaw portion 704. As shown in Fig. 24, when stent rod 712 is
sufficiently retracted in the proximal direction, jaws 720A and 720B can be
properly closed about stent 600. Closure of the jaws is accomplished by
causing
inner tube 710 to move distally relative to jaws 720A and 7208, thereby
causing
the distal end of tube 710 to contact the proximal ends of the jaws. This
contact
causes the jaws to pivot toward each other and close. Means for causing inner
tube 710 to move relative to the proximal ends of jaws of 720A and 7208 are
disposed in proximal handle assembly 706. As shown in Fig. 24, movement of
level 716 towards handle assembly 706 causes linkages 722 to move inner tube
710 in a distal direction. A similar closure mechanism is disclosed in
commonly
assigned U.S. Patent No. 5,040,715 wherein an anvil member is cammed towards
a staple carrying member by means of relative movement with respect to an
inner
tube. It is to be understood that jaw approximation by means of manipulating
an
inner tube is but one method of closure and that those skilled in the art
could
devise other suitable means for closing jaws 720A and 720B, such means are
considered to be within the scope of the present invention. For example,
closure
by means of a cam pin disposed in cam slots in the proximal ends of the jaws,
as
disclosed in Fig. 3, is also a suitable means for closing the jaws of stapler
700.
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CA 02493157 1994-04-19
Stapler 700 further includes means for rotating endoscopic portion 702 and jaw
assembly 704 relative to handle assembly 706. Rotation knob 724 is disposed
about endoscopic portion 702 and may be integral with outer tube 708 (similar
to
rotation portion 76, shown in Fig. 3). Locking member 726 provides means for
locking endoscopic portion 702 relative to handle 706. A detailed description
of a
similar locking mechanism is disclosed in commonly assigned U.S. Patent No.
4,728,028.
Handle portion 706 includes rear handle 728, trigger 731 and safety 729
disposed
therebetween. After properly positioning stapling portion 704 about organs to
be
joined, safety 729 can be deflected to permit movement of trigger 731. Trigger
731 functions to eject staples from the instrument which will be described in
greater detail below.
Turning to stapling assembly 704, with reference to Fig. 25, jaws 720A and
7208
house similar, opposing staple carrying and firing elements. While stapling
assembly 704 will be described with reference to lower jaw 7208, jaw 720A has
substantially identical components facing in an opposite sense. The staple
firing
mechanism generally includes slidable cam plate 7308, stationary cam plate
7328
and staple deforming bars 7348 and 7348'. Staple bars 7348 and 7348' have
cam posts 7368 which are slidably received in lateral slots 7388 in cam plate
7328 and through slanted slots 7408 in cam plate 7308. Cam plate 7308 and
7328 are received in recess 721 in lower jaw 7208. Slidable cam plate 7308 is
operably associated with trigger 731 such that movement of the trigger causes
plate 7308 to move relative to plate 7328. Means for connecting plate 7308 to
trigger 731 include cable, wire, tubular structures and the like.
Staples 7428 are disposed between staple deforming bars 7348 and 7348' which
have shoulders 744 and slots 7458 to facilitate placement and storage of
staples
7428 therein. Staples 7428 are disposed with backspans 741 perpendicular to
axis X-X of the instrument (similar to the staple orientation in Figure 11 ),
and have
prongs 743 oriented towards jaw 720A. While two staples are shown with
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CA 02493157 1994-04-19
reference to jaw 7208, obviously, any number of staples suitable for
performing a
surgical procedure can be disposed between the staple forming members 7348.
In order to deform staples 7428 to a closed configuration, slidable cam plate
7308
is urged in a proximal direction. Proximal movement of plate 7308 causes cam
posts 7368 to travel along slots 7408 and 7388, thereby causing staple
deforming
bars 7348 and 7348' to slide laterally. Lateral movement of both staple
deforming
bars causes staples 7428 to deform to a closed configuration.
Use of the novel stapling device in performing an end to end anastomosis
procedure is shown in Figures 26-29. In operation, stent 600 is positioned
distally,
away from jaw assembly 704 by advancing stent rod 712 in a distal direction.
Tubular organ sections 750 and 752 are then positioned over the flat portions
of
stent 600. As shown in Figs. 26 and 27, stent rod 712 extends past stent 600.
This extension facilitates preventing over placement of the tubular organ
sections.
Though not shown in this embodiment, stapling portion 704 can be fabricated to
articulate with respect to endoscopic portion 702, in a manner similar to that
disclosed above, to facilitate placement of tissue. After the tubular organs
have
been placed over stent member 600, stent 600 and rod 712 can be retracted by
sliding knob 714 (Fig. 23) to position tubular organs 750 and 752 between jaws
720A and 7208. Jaws 720A and 7208 can then be closed, i.e., by causing inner
tube 710 to move distally. Distal movement of inner tube 710 causes the distal
end of tube 710 to cam against the proximal end portions 719A and 7198 of the
jaws (Fig. 25) which further causes jaw portions 720A and 7208 to pivot about
pin
721. Alignment means for ensuring proper orientation of the stent rod and
stent
relative to the jaw assembly can also be provided. As shown in Figs. 26 and
27,
alignment projections 746 and 748 have recesses 747 and 749, respectively,
which are configured and dimensioned to receive the distal end of stent rod
712.
To fire the instrument, safety 729 (Fig. 24) is disengaged and trigger 731 is
pulled
in a proximal direction, thereby causing movable cam plates 730A and 7308 to
move in a proximal direction, as described above. With reference to Fig. 28, a
cross sectional view of distal stapling assembly 704 is shown after firing.
Arrows K
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CA 02493157 1994-04-19
depict lateral movement of staple pushing members 734 which have moved
inward to deform staples 742 into a pretzel-shaped configuration, thereby
joining
tubular organs 750 and 752.
With reference to Fig. 29, after firing the instrument jaws 720A and 7208 are
opened and moved proximally in the direction of arrow L, away from the tubular
organs. Withdrawal of the instrument causes stent rod 712 to be withdrawn from
orifices 612 of the fragmentable stent, thereby permitting the stent to
fragment
within the joined organs. Alternatively, stent rod 712 can be withdrawn prior
to
firing the staples. Stent portion 601-604 may then pass through the body.
While surgical stapler 700 has been shown in conjunction with the use of a
stent
and stent rod, the instrument can be used without a stent. With reference to
Fig.
28, for example, when jaws 720A and 7208 are closed about tubular organs,
tissue can be forced between prongs 743 of staples 742. Upon firing of the
instrument, staples 742 are closed in such a manner as to engage and
approximate the tubular organs. With reference to Figure 14a, if the tubular
tissue
sections to be joined are of different diameter, the smaller diameter tissue
303
(having diameter Y) can be cut at an angle a~ so that the angled cut line is
dimensioned closer to diameter z of tubular tissue 304. With angled tubular
tissue
303 approximated and juxtaposed to tubular tissue 304, the two tissues can be
joined by fasteners, such as, for example, staples ejected from the surgical
stapling instrument disclosed herein.
Expandable stem 450 (described above) and fragmentable stent 600 can be
fabricated from any suitable bio-compatible material. Preferably, absorbable
materials, such as those comprising glycolide and lactide, are used. Most
preferred are stents made from materials which soften over time when exposed
to
body tissue and fluids. Stents made from polyvinyl alcohol (PVA), for example,
are sufficiently rigid to permit expansion and approximation of tissue, yet
soften
over time to permit safe passage of the stent after the tissue has been
joined, e.g.,
by stapling. Suitable plasticized PVA resins are available from Air Products
and
Chemicals, Inc., Allentown, PA under the VINEX~ trademark. VINEX~ 2025, for
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CA 02493157 1994-04-19
example, can be extruded into a film and compression molded to obtain a stent
part. Alternatively, PVA can be plasticized with water, converted into film by
compression molding and then compression molded into a stent part.
The following examples relate to the preparation of suitable stents.
EXAMPLE I
Preparation of stent using
VINEX~ plasticized PVA film
1. Provide a mold configured to the dimensions of the stent (see step 3).
2. Spray a light, thin film of heat-stable silicone release agent on parts of
the mold to which the PVA will be exposed. Remove any excess.
3. Using scissors, carefully cut a piece of PVA film (VINEX~ 2025
plasticized PVA film extruded to a thickness of about 0.045") with
dimensions 1 '/2" x 3/". Place the film on the cavity insert of the mold.
The cavity insert has dimensions 1 5/16" x 5/8". Put the mold together
and place in a platen press.
4. Set the platen temperature to 150°C.
5. Close the plates of the oven and set the kiss pressure at either 0 or
1000 Ibs./sq. inch. Set the time at approximately 25 minutes. The
duration must be long enough such that the plates reach 150°C. during
the kiss.
6. Set the cure pressure at 40,000 Ibs./sq. inch for four minutes. Set the
mist for five minutes and the cool for ten minutes.
7. The press will open when the cool has finished. Take the molded part
out of the mold and place in a dry room.
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CA 02493157 1994-04-19
EXAMPLE 11
Preparation of PVA film and stent
1.0 Preparation of Film.
1.1 Weigh out 7.5~.5 gm PVA (7800 molecular weight, 88% hydrolyzed).
1.2 Weigh out 3.75~0.25 gm warm pyrogen free water.
1.3 Add water to PVA. Add approximately one ml and mix vigorously.
Continue to add one ml at a time and mix until all water is used.
1.4 Roll into a tight ball using your hands.
1.5 Place the ball on top of a teflon-coated aluminum plate in a platen
press with 0.025" feeler gauges alongside the ball. Place another
Teflon coated aluminum plate on top of the ball.
1.6 Set the press close delay to 0.1 hours and vacuum to 0.2 hours while
setting the plate temperature to 170°C.
1.7 Set the kiss to approximately 15 minutes. The kiss duration should
be long enough to allow the temperature to reach 170°C and hold
there for two minutes. The pressure should be 1000 Ibs./sq. inch.
1.8 Set the cure to five minutes with pressure at 30,000 Ib./sq. inch.
1.9 Set the mist to five minutes and cool to six minutes.
1.10 The press will open after the cool is completed. The teflon-coated
plates should come apart easily. The film should look clear and
should be placed under vacuum for 18 hours at approximately 60°C.
2.0 Preparation of Stent.
2.1 Spray a light, thin film of heat-stable silicone release agent on the
parts of the mold to which the PVA will be exposed. Remove any
excess.
2.2 Using scissors, carefully cut a piece of the PVA film with dimensions
1 '/2" x 3/". Place the PVA film on the cavity insert. The cavity insert
has dimensions 1 5/16" x 5/8". Put the mold together and place in
the platen press.
2.3 Se the platen temperatures at 175°C.
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CA 02493157 1994-04-19
2.4 Close the plates of the oven and set the kiss pressure at either 0 or
1000 Ibs./sq. inch. Set the time at approximately 25 minutes. The
time must be long enough such that the plates reach 175°C and hold
for two minutes.
2.5 Set the cure pressure at 40,000 Ibs./sq. inch for four minutes. Set
the mist for five minutes and the cool for ten minutes.
2.6 The press will open when the cool has finished. Take the molded
part out of the mold and place the part in a dry room.
While the invention has been particularly shown and described with reference
to
the preferred embodiments, it will be understood by those skilled in the art
that
various modifications in form and detail may be made therein without departing
from the scope and spirit of the invention. For example, various elements,
such as
the jaw closing mechanism, the stapling firing mechanism and the articulation
mechanism, can be modified while still performing the same or similar
function.
Additionally, while the surgical stapling devices 10 and 700 have been
particularly
adapted for endoscopic use, the instruments of the present invention can also
be
used in open procedures. Such procedures include end-to-end and side-to-side
anastomosis of tubular organs such as intestines, arteries and the like.
Accordingly, such modifications are to be considered within the scope of the
invention as defined by the claims.
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