Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to an instrument for circular
surgical stapling of hollow body organs and more particularly,
to aln instrument for effecting end-to-end anastomoses, side-to-
side~ and side-to-end anastomoses and a disposable cartridge
therefor.
Presently in the prior art, several instruments are
known for circular joining by staples of hollow body organs.
United States Patents Nos. 3,638,652, 3,552,626, 3,388,4~7 and
3,193,165 all relate to instruments of this type, which are
useful in surgical procedures involving the colon and the
esophagus. Despite the fact that these instruments are known
in the prior art, they have never been introduced into practical
use in the United States apparently for their lack of versatility.
For exaople, these instruments, which are disclosed in the
aforementioned patents, have the important drawback requiring
hand loading of the suturing staples into the staple magazine
of the instrument after each use of the instrument. This means
that once the instrument is actuated and its staples ejected
and clinched, it must then be set aside and the magazine must
then be refilled with staples by hand. While refilling, the
instrument, of-course, is inoperative and may not be further
used in the on-going surgical operation. The aforementioned
U.S. Patent No. 3,552,626 discloses a form of the instrument
in which the staple magazine and associated anvil of the instrument
~.
are interchangeable so that different sizes may be mounted on the
same instrument body but this arrangement is solely for the
purpose of accommodating hollow body organs of different sizes.
Thè present invention is directed to an instrument
of the type generally described and was developed to overcome
the drawbacks and disadvantages which one experiences when
; attempting to use similar instruments according to prior art
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113i3Z36
teachings and most notably, those teachings which are contained
ïn the aforementioned patents.
Accordi,ngly, the present invention provides a two-part
disposable cartridge assembly for stapling a circular pattern in
hollow organs comprising an anvil-carrying part composed of a
dish-shaped body and an anvil providing a pair of concentric cir-
cular arrays of staple-clinching grooves mounted on said dish-
shaped body, and a staple-carrying part composed of a guide body
defining a pair of concentric circular arrays of stapleholding
grooves,a staple ejector means mounted in said guide body for
relative movement thereto so as to drive staples in the staple-
holdin~ grooves towards the staple-clinching grooves of the
anvil, and knife means carried by said ejector means and moveable
towards co-operating means on said anvil-carrying part for trim-
ming excess tissue from stapled organs during a stapling opera-
tion.
An instrument body is also described which is special-
ly designed to accommodate the staple-carrying part and staple-
clinching part in a readily detachable fashion so that these
parts can be fabricated as a disposable cartridge. Accordingly,
successive uses of an instr~nent during surgical procedure are
easily attained simply be detaching a spent cartridge and re-
placing with a fresh cartridge. Proper connection and keying to
the disposable cartridge to the body of the instrument is also a
feature of the invention to ensure that all parts are in the
correct orientation and properly indexed; hence when the instru-
ment is actuated, the staples are ejected through the tissue of
the hollow body organ and~clinched to effect the desired staple
line.
The instrument may be used for effecting end-to-end
anastomoses or end-to-side anastomeses by means of a pair of
concentric circles of staples of high security in maintaining
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the desired tissue joining. Variations in staple dimensions and
array pattexns are easily provided by a variety of cartridge
des.igns.
Further advantages and details of the present invention
will become more evident from a consideration of the following
descriptive text when taken in conjunction with the appended
drawings, in which:
Figure 1 is a view in side elevation showing the novel
instrument assembled with a disposable cartridge;
.
. - 3a -
113~Z8~
Figure 2 is an end view of the disposable cartridge
illustxated in Figure l;
Figure 3 is a sectional view taken along line 3-3
of Figure l;
Figure 4 is a sectional view taken along line 4-4
of Figure l;
Figure 5 is an end view of the instrument looking
at the adjustable wing nut;
Figure 6 is a view partly in section through the
main body of the instrument showing the man~er in which the
instrument is assembled and the handle is manipulated to cause
the reciprocating motion of the driver;
Figure 7 is a sectional view of Figure 6 taken
along line 7-7;
Figure 8 is a view in section through the body of
the instrument showing the stop arrangement in detail;
Figure 9 is a view in top plan partly in section
of the staple carrying part of the disposable cartridge showing
the keying arrangement;
Figure 10 is a view in section through the staple
carrying part of the disposable cartridge;
Figure 11 is a view in section taken along line
11-11 of Figure 10;
Figure lla is a view in section through the keying
arranyement illustrating positions following staple ejection;
~igure 12 .is a.front end view of the staple carrying
part of the disposable cartridge showing the pusher and
knife;
. Fiqure 13 is a detail section showing safety detent
arrangement
3Z~
Figure 14 is a front end view showing the pusher
and staple guide;
Figure 15 is a side elevational view showing
coaction between staple and pusher;
Figure 16 is a side view, partly in section showing
the anvil part of the disposable cartridge;
Figure 16a is a top view in section along line
16a-16a of Figure 16;
Figure 17 is a view of Figure 16, with anvil
removed;
Figure 18 is a side elevational view of the anvil;
Figure 19 is an elevational view of the anvil;
Figure 20 is a vi~w in section through the anvil;
Figure 21 is a view in section through the anvil
illustrating the manner in which a staple is clinched; and
Figure 22 is a view in section through the anvil
part of the disposable cartridge showing the staple line
and knife cutting of tissue.
Referring now to the drawings in detail, a preferred
embodiment of the instrument with disposable cartridge mounted
thereon according to the teachings of the present invention
is depicted in Figures 1 and 6. As shown, the instrument
comprises a main body or housing defining a throughbore 11 and
having an integrally formed rear handle part 12. Projecting
from the body 10 is a pivotally mounted handle part 14, pivotably
mounted to the body 10 by means of pivot pin 16. The handle
part 12 is received in the palm of the hand of the operator
and the handle part 14 is grasped by the fingers of the same
hand. When the fingers are squeezed toward the palm, handle
part 14 is pivoted about pin 16 and~brought toward handle
part 12. A conventional safety bar 18, terminating in a knob
113i~;ZB6
20 bearing against the pivotable handle part 14 and which,
in ~urn, is pivotally mounted on a pin 22 set into the body
10, serves as a safety to yrevent the accidental actuation of
hanclle part 14. Safety 18 is conventional in both function
and struc~ure.
Projecting from the forward end of the body or housin~
10 is an outer tube 30 which extends forwardly and terminates
at a substantial distance from housing 10. Received on the
remote end of tube 30 is a disposable cartridge referred to
generally by the reference numeral 40. Attachment of disposable
cartridge 40 to the tube 30 is effected by means of a threaded
coupling sleeve 42 in a manner which will be described herein-
after. The disposable cartridge 40 comprises a staple carrying
member 44 and an anvil carrying member 46. Concentrically
mounted within the tube 30, is a driver tube 50 and a rod 52.
Driver tube 50 reciprocates within tube 30 and serves as a
pusher for ejecting staples; the rod 52 reciprocates independent
of driver tube 50 and serves to position the anvil carrying
member 46 relative to the staple carrying member 44. The rod 52
extends entirely through the instrument with one end projecting
out of the front of the instrument to receive and carry the
anvil carrying member 46 and the other end projecting out of
the back of the instrument through a wing nut 60. The rear
end of the rod 52 is threaded as indicated to the right of
Figure 1 and is in threaded engagement with an internally
threaded sleeve extension 110 of wing nut 60.
As illustrated in Figure 3, the inside diameter of
tube 50 is slightly enlarged at its remote end, for the purpose
of relieving the contact between the rod 52 and driver tube
50 over a substantial area without'any loss of function.
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113828~
As shown in Figure 5, an end cap 62 is applied to
the rear of the instrument and effects a closure of throughbore
11. Cap 62 secures stepped bushing 304 against shoulder 306
in throughbore 11. The smallest bore through bushing 304
supports reduced part 106 of the rod 52 and terminates in
bevelled shoulder 130. Holes 64 are provided in the cap 62
in order to accommodate a suitable spanner wrench to enable
the attachment of the cap 62 into a suitably threaded terminal
part of throughbore 11 at the rear of the instrument. The
cap 62 contains an external thread on its flange part that
coacts or threadedly engages with the thread formed in the
terminal part of throughbore 11.
Referring now to Figures 6, 7, and 8, the internal
arrangement for the body or housing 10 will now be described
in detail. As already noted, the cap 62 contains an external
thread which threadedly engages with an internal thread suitably
formed in the terminal part of the throughbore 11. This
threaded engagement is identified generally by the reference
numeral 66. Throughbore 11, at its end proximal to the disposable
cartridge mounting, receives the outer tube 30 which extends
into the throughbore 11 terminating at the entry to an enlarged
region 70 of the bore 11. The body 10 and the tube 30 are
rigidly interconnected in the bore 11 so that there is no
relative motion between them. The driver tube 50 extends
-: ;
coaxially within the sleeve 30 and projects therefrom into
the enlarged region 70 where upon it is threadedly connected
at its end by means of threads 74 with a short thicker sleeve
72. This sleeve 72 in turn is connected by means of threads
76 with a terminating cap 78. This terminating cap 78 defines
on its inner surface an inclined stop shoulder 81. The driver
tube 50 together with the short sleeve 72 and the cap 78 being
_7_
threaded together all move as a unit. The short sleeve 72
being somewhat thicker than the driver tube 50 accommodates on
either side a roller 80 which is mounted on a short stub shaft
88 pressed into a recess defined in the short sleeve 72.
Rollers 80 are provided on diametrically opposed sides of the
short sleeve 72 and serve as the means by which the driver
tube 50 is reciprocated in the instrument. Also, the underneath
side of the short sleeve 72 is provided with a suitable tapped
hole 84 into which is threaded a projection 82. The stub or
projection 82 extends downwardly, as protrayed in Figure 6
of the drawings, and terminates in the plane of a slot 84
defined in the body lO. The purpose of the stub or projection
82 is to maintain a proper orientation for the driver tube 50 as
its reciprocates back and forth; hence, stub or projection 82 in
cooperation with slot 84 prevents driver tube 50 from rotating
during reciprocation.
The arrangement for reciprocating the driver tube
50 is illustrated best in Figures 6 and 7. As already noted,
the short sleeve 72 carries rollers 80 on diametrically
opposed sides, the rollers 80 being mounted for free rotation
by means of short stubs 88 which are pressed into the short
sleeve 72 in the manner best illustrated in Figure 7.
The handle part 14 is provided at its lower end with a
- bifurcated member 90, the legs of which are identified by
the reference numeral 92. These legs 92 are fashioned as
forks 94 which engage the rollers 80. The bifurcated member
; 90 is designed with an upstanding central projection 96 whïch
` fits into a slot 97 defined in the lower part of the handle
part 14. Pins 98 projecting through holes formed in projection
96 hold the bifu,rcated member 90.to~the handle part 14. Handle
part 14 pivots abou~ pin 16 as shown in Figure 6, and forks 94
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.
~13~ZB~
cooperating with rollers 80 cause driver tube 50 to reciprocate
in tube 30. A spring 56 received around tube 50 in region
70 biases sleeve 72 against the reciprocation produced by
handle part 14. The left end of spring 56 is held against the
end of tube 30.
The rod 52 extends completely through the tube 30
and body 10 of the instrument. As will be evident from Figure
8, the rod is provided with a bevelled shoulder 100 connecting
the main portion of the rod 52 with a reduced portion 102 which
in turn defines a bevelled shoulder 104 with a further reduced
part 106 of the rod 52. The extreme right end of the rod is
a further reduction in diameter~ this portion being identified
by the reference 108, and this reduced section 108 is threaded
throughout its length.
The wing nut 60, which appears at the rear of the
instrument, is provided with a sleeve extension 110. A reduced
portion 112 interconnects sleeve 110 with the hub of nut 60,
which reduction defines a groove into which a retaining ring
124 is received for the purpose of securing the wing nut 60
and its sleeve extension 110 onto the end cap 62. The sleeve
extension 110 as well as nut 60 define a throughbore through
which rod 52 passes. The bore within the sleeve extension 110
is threaded to threadedly engage with the threads defined on
the reduced portion 108 of the rod 52. By the arrangement
described, when the cap 62 is threaded into the body 10 with
the wing nut 60 held thereon by means of the retaining ring
124, the wing nut 60 will not translate when rotated because
of being secured to the end cap 62 in the manner described.
Accordingly, sleeve extension 110, acting as a nut on the threaded
part of rod 108, wlll cause the rod 52 to reciprocate.
The bevelled shoulder 104 acts as a stop working
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~13~36
against a bevelled shoulder 130 defined in the bushing 3
The furthest position of the rod 52, that it may assume when
driven to the right by means of sleeve extension 110, is
illustrated in Figure 8 with the bevelled shoulder 104 and
the bevelled shoulder 130 in contact. This also represents
the closest approach of the anvil-carrying part 46 to the
staple-carrying part 44 of the disposable cartridge. This
position of closest approach is illustrated in Figure 1 and
is selected to define a space between the two parts of the
disposable cartridge that is equal to the minimum spacing required
to accommodate tissue from whatever hollow body organs are
to be stapled by the instrument of the present invention.
Referring now to Figures 9, 10 and 11, the staple-
carrying part 44 of the disposable cartridge will now be described
in detail. The part 44 is an assembly comprised of a main body
portion 140 having an hemi-ovate shape terminating at its
right end in a small diameter neck 141 having external threads
142. These threads 142 cooperate with an internally threaded
coupling sleeve 42 which is retained on the end of the tube
30 by means of shoulder 146. A guide member 148 provided with a
slot 150 coacting with a projection 152 defined on the main
body part 140 for orientation is secured to the main body part
140 by an adhesive or the like, the area of securement being
identified by the reference numeral 154. The guide member 148
forms a guide face 156 which defines two concentric circular
series of spaced staple-receiving slots 158. Received within
; the guide member 148 and the main body part l40 is a staple
ejection member 160, which fits concentrically within the
main body part 140, terminates in a long neck 161 and is adapted
to be contacted by the end of driver tube 50. The forward
end of the staple ejector 160 is defined with two concentric
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.
~3~ii286
rings of peripherally spaced fingers 162, each one of which
is received within a staple-receiving slot 158. Hence, upon
advancing the staple ejector 160 by driver tube 50, the fingers
162 will pass further into the staple-receiving slots 158,
ejecting staples contained therein axially outwardly. The
staple ejector 160 is reinforced with a plurality of ribs 164 at
least two of which are provided with suitable plastic projections
or bosses 166. A knife 168 in the form of an open cup with
the rim defining the knife edge 170 is mounted within the staple
ejector 160 by means of holes 173 through which the bosses 166
project. In mounting, the bosses 166 are "hot staked" to
fasten the Xnife 168 onto the staple ejector 160 so that
advancement of the staple ejector 160 also advances knife 168.
A two-headed key 180 is press fitted into an opening
or slot defined in the outer tube 30. The outer head 182 of
the key is somewhat enlarged and coacts with a slot defined
in the small neck of the main body part 140 to maintain this
body part 140 and the associated guide member 148 in a
predetermined indexed orientation with respect to the double-
headed key 180. The driver tube 50 is provided with an elongated
slot through which the key 180 passes in a loose fashion and
the rod 52 is provided with a close fitting slot 184 into which
the other end of the key 180 is received.
When initially assembled, the guide member 148 and
the staple ejector 160 which define mutually opposed detents
l90 and 192, respectively, are orientated such that detent
192 formed on the outer periphery of the staple ejector 160
is to the right of the detent 190 as shown in Figure 13.
The purpose of these mutually opposed detents is to prevent
any outward motion of the staple ejector 160 and its associated
knife 168, that is outward from the face 156, and thereby
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113~2~
prevent any accidental dischar~e of staples or accidental
projection of the knife, before assembly onto tube 30.
When the staple carrying part of the disposable
car~ridge is assembled onto the end of the outer tube 30 by
means of the sleeve 42 and the mutually engaging threads of
the sleeve and the small neck of the main body part 140, the
main body part 140 will be drawn to a position such that the
staple ejector 160 will engage the free end of the driver tube
50 and then be moved slightly outwardly relative to the main
body part 140. This will cause the detents 190 and 192 to
reverse themselves from the position shown in Figure 13 to
the position shown in Figure 10. The staple-carrying part 44
will then be ready for use.
The rod 52 is provided at its free end with a key
200 for the purpose of indexing the anvil-carrying part 46 to the
rod 52. The rod 52, is also provided at its free end with a
tapped hole 202 for the purpose of detachably mounting the
anvil-carrying part 46.
The anvil carrying part 46 is illustrated in Figures
16-22 inciusive and comprises a plastic body portion 210 of
cup shape with a central hub 2~2 defining a bore 214. A stud
216 is received through the bore 214 and is characterized by knob
48 at one end and a screw thread 220 at its other end with a
reduced section 2?2 defined between its ends. The threading
220 matches the internal threading of the bore at the end
of rod 52. Clips 224 defined by the portion 210 Droject into the
bore 214 and engage the shoulder defined by the reduced section
` 222 to hold stud 216 captive in bore 214 but allowing it to rotate
freely. The body portion 210 in the vicinity of bore 214 is
cutout 226 to accommodate the key.20~0 at the end of rod 52.
Holes 49 provide venting for the anvil carrying part 46. Metal
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2i~3~
anvil 230 havin~ two concentric circular arrays of spaced
staple clinching grooves 232 and a central hole 233~ is mounted
onto body portion 210 by "hot staking". Body portion 210 defines
a plurality of ribs 234 at least two of which are provided with
projections or bosses 236. Anvil 230 defines matching holes
238 and after mounting, bosses 236 are melted to form rivets
240 to lock anvil 230 on, see particularly Figure 22. Anvil
230 is also provided with punched out lips 242 to secure a
cutting block 244 of annular configuration, that cooperates with
knife 168. Cutting block 244 is rubber, soft plastic or the
like. Anvil 230 defines a cutout or keyway 231 as an extension
of hole 233 that coacts with key 200 to insure the proper
orientation and indexing for grooves 232 of the anvil 230
relative to slots 158 of the staple carrying part 44. Anvil
230 has vent holes 47 which communicate with vent holes 49 in
body 210.
In operation, wing nut 60 is rotated to advance rod 52
out from the end of tube 30. A staple carrying part 44 of a
disposable cartridge 40 is fitted over rod 52 and tube 30 and
attached to tube 30 by sleeve 42. The geometry of these parts is
such that key i80 engages the neck of staple carrying part
44 before the threading engages to draw part 44 onto tube 30
to i~ts seated position. During the last turns of sleeve 42,
the end of driver tube S0 engages the staple ejector 160 to
reverse the detents 190 and 192 from the position shown in
Figure 13 to the position shown in Figure 10.
Next, the anvil carrying part 46 is assembled into the
end of projecting rod 52. To this end, the knob 48 is grasped
and the pointed threaded end of stud 216 is introduced into the
tapped hole in the end of rod 52. ~ey 200 is received at this
time in keyway 231 of anvil 230 before the threading engages,
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113i~Z~36
whereafter knob 48 is rotated to seat threaded end 220 of stud
216 into the tapped hole at the end of rod 52 and draw the key
200 into the keyway 231. Keys 180 and 200 assure that slots 158
and grooves 232 are properly aligned. Wing nut 60 is then
rotated to retract rod 52 and thus bring anvil part 46 close to
staple carrying part 44.
In this condition, the instrument is inserted into
the patient through the hollow organ that is to be stapled.
At this time, the patient has been prepared such that the
hollow organ to be stapled has been cut and there are two cut
ends to be joined together by means of the instrument of the
present invention. The instrument is inserted through the
hollow organ until it projects from one of the cut ends. The
wing nut 60 is rotated to extend the rod 52, thereby creating a
substantial gap between the anvil-carrying part 46 and the
staple-carrying part 44.
Now, the cut end of the hollow organ through which
the instrument is protruding is fashioned with a drawstring
suture and drawn over the staple-carrying part 44 about the
rod 52. The other cut end of the hollow organ is pulled over
the anvil-carrying part 46 and by means of a drawstring suture
is tied closely about the rod 52. Thus, the two cut ends of
the hollow organ will be interposed between the anvil part 46 and
the staple-carrying part 44. At this time, the wing nut 60
is rotated to cause retraction of the rod 52 whereupon the
anvil-carrying part 46 will be brought into close proximity
` with the staple-carrying part 44. Wing nut 60 is turned until a
sufficient back pressure is felt caused by squeezing the
tissue interposed between the staple carrying part 44 and the
anvil carrying part 46.
At this time, the rod 52 will occupy a position
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1~L3~2~3~
within the body 10 of the instrument either as shown in
solid lines in Figure 8 with the stop 104 bearing against
the stop 130, or due to a greater than minimum thickness of
entrapped tissue, the stop 104 will be axially displaced off
of l;he stop 130 to the left as shown in phantom.
With the apparatus in the condition described,
that is, with the cut ends of the hollow organ to be stapled
drawn around the two disposable parts of the cartridge, the
safety 18 is released by pivoting away from the handle part
14 toward the handle part 12 in the manner shown in phantom
in Figure 6 and the handle is grasped with the handle part
12 resting in the palm of the hand and the fingers curled
about the handle part 14. When the fingers are drawn toward
the palm of the hand in the manner of making a fist, the
handle part 14 will be rotated about its pivot pin 16 clockwise
as shown in Figure 6 toward the handle part 12. This causes
the forks 94 to advance the rollers 80 and the sleeve 72 axially
to the left as shown in Figure 6 and as indicated by the
arrow. This action will force the driver tube 50 which is
threaded into the sleeve 72 to the left as viewed in Figure
6 against the bias of spring 56. Advancement of driver tube
50 will in turn produce an advancement of the staple ejector
160 since the neck 161 of this part is in contact with the end
of the driver tube S0. Advancement of the staple ejector 160
will cause the fingers 162 to move through the respective
slots 158 ejecting the staples 159 contained therein. The
action of the fingers 162 against the staples 159 is depicted
in Figure 15; the forward faces of the fingers 162 are all
provided with a V-groove 163 in which the crossbar of the U-
shaped staple 159 is received~ Thi~ assures a better contactbetween the finger 162 and the staple 159 during ejection.
-15-
~.3~2a~
Referring to Figure 21, the action that takes place
during ejecting of the staple 159 is generally depicted; as
the staples 159 are advanced or ejected out ~rom the slots
158, they are contacted by ~rooves 232 of the anvil 230 and
bent into a conventional ~-shape as depicted in Fi~ure 21.
Simultaneously with the advance~ent of the staple ejector 160,
the knife 168, which is carried by the staple ejector 160, is
axially advanced toward the anvil-carrying part and the knife
edge 170 of the knife 168 will intersect with the interposed
tissue ends of the trapped hollow organs (shown in phantom in
Figure 22 at 300 and 302~ so as to trim the excess tissue
during the stapling operation. The cutting edge 170 of the
knife 168, which is circular in configuration, cuts through
the tissues 300 and 302 and into the annular cutting block 244,
which is held within the anvil 230 by means of the punched-
out parts 242, as previously described. The advancing of
driver tube 50 continues until stop 80 engages stop 100 on rod
52, the location of stop 100 being variable in dependence upon
tissue thickness. Fïowever, regardless of the variable loca-
tion of stop 100, driver tube 50 will travel whatever distance
is necessary to bend the staples always into the same configura-
tion. There is, of course, a r.laximur.l limit to tissue thick-
ness which a specific staple length can accommodate. Figure
22 depicts i.n phantom the two concentric circular arrays of
staples 159 which join together the ends of the hollo~ organ
to be joined. The excess portion of the ends of the hollow
organ to be joined are s.evered by the action of knife edge 170.
The vent holes 47 in anvil 23Q and vent holes 49 formed in the
body 210 a,llow for .relief ~ gas,, fluid or excess tissue
trapped ~i.th~n the in~tXu~ent on ,a,ccount of the procedure of
stapling. The severed ends 300 and 302 of the hollo~ or~an
are retained ~ithin the
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.~ ~
1~3i~;Zati
cavity defined between the anyil-carrying part and the staple-
carrying part.
The next step in the procedure would be to rotate
wing nut 60 to slightly increase the spacing between the anvil-
carrying part and the staple-carrying part to allow the stapled
part of the hollow organ to be withdrawn from between these
instrument parts and passed over the anvil-carrying part 46 so
that the instrument may be withdrawn. To this end, the anvil-
carrying part 46 is provided with an external configuration
of dish-shape to facilitate the removal of the stapled organ from
between the two parts 46 and 44 and passing of the stapled part
of the organ over part 46.
This removal is best accomplished when the perimeter
of the profile, in section through the axis as shown in Figure
16, an anvil-carrying part 46 is equal to or less ~han the
circumference of the inner ring of staples represented by the
inner circular array of spaced staple clinching grooves 232 in
Figure 19.
Although the present invention has been shown and
described in terms of a preferred embodiment, it will be
appreciated t~at various changes may be made without departing
from the spirit of the concept. For example, the attachment
of the anvil-carrying part 46 and the staple-carrying part 44
has been shown as a threaded engagement or attachment. It is
. .
important that the attachment be one that may be easily performed
in an operating theater and under difficult or extreme conditions._
Accordingly, any known technique for effecting connection between
the parts 44 and 46 and the outer tube 30 and the rod 52,
respectively, which would enable quick attachment and detachment
would be suitable, for example, bayonet types of connections.
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