CA1272930A

CA1272930A - Surgical stapling apparatus

Info

Publication number: CA1272930A
Application number: CA000548388A
Authority: CA
Inventors: David T. Green
Original assignee: United States Surgical Corp
Current assignee: United States Surgical Corp
Priority date: 1986-11-13
Filing date: 1987-10-01
Publication date: 1990-08-21
Anticipated expiration: 2007-08-21
Also published as: EP0270260B1; US4776506A; ATE80985T1; EP0270260A1; DE3782009D1; ES2035081T3; DE3782009T2

Abstract

ABSTRACT OF THE DISCLOSURE

The end-to-end anastomosis surgical stapling apparatus is actuated in a single step. The apparatus includes a shaft which is able to pull the stapling anvil proximally in one step relative to a stationary housing as well as a plurality of circumferentially disposed balls mounted in cage-like manner in the housing which serve to lock the sleeve relative to the housing. The sleeve carries the staple cartridge and is released to move with the anvil when the anvil clamps the tissue against the cartridge. Thereafter, cam surfaces on the shaft and the sleeve permit the balls to move radially inwardly releasing the sleeve for proximal movement relative to the housing so that the staples pierce the tissue for stapling purposes.

Description

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SURGICAL STAPLER APPARATUS
1 This invention relates to a surgical stapler apparatus.

2 More particularly, this invention relates to a flexible

3 surgical stapler apparatus for use in end-to end anastomosis.

4 As is known,various types of surgical stapling devices have been used for the stapling of tissue. In particular, 6 various types of devices have been known for an end-to-end 7 anastomosis for rejoining the lumen of a tubular organ. In 8 such cases, the devices have been provided with a stationary 9 anvil against which staples may be formed by applying a force through staple pushers which serve to eject the staples from a 11 cartridge against the anvil~ In addition, these devices have 12 also ~mployed a flexible shaft, for example, as described 13 in U.S. Patents 4,485,817 and 4,488,523 for th~ stapling of 14 sites which may be inaccessible for devices having a rigid shaft.
16 European Patent Application 0173451, published March 5, 17 19~6 describes a flexible stapIer assembly having an anvil 18 which is movable against stationary staples. As described, a 19 staple pusher is mounted in a statlonary manner on a firing head assembly while a cable is secured to the anvil for 21 pulling of the~anvil relative to the stationary staple pusher 22 in order to drive the staples through the tissue to be stapled.
23 However, the described assembly requires a numher of springs 24 which, in turn, complicate the construction as well as the ~5 operation of the assembly.
26 Accordingly, it is an object of the invention to 27 provide a surgical stapler apparatus of relatively simple 28 construction having a movable anvil.
29 It is another obiect of the invention to simplify the construction of a flexible stapler apparatus employing a . ~ ,:`

1 ~I movable anvil.
2 1I Briefly, the invention provides a surgical stapler 3 ~1 apparatus, for example of the flexible end--to-end anastomosis 4 ,¦ type, which employs a housing and a shaf~ which is movably

5 1~ mounted in the housing for relative longitudinal movement. In !l addition, an anvil is mounted on a distal end of the shaft, an 7 ¦ annular knife projects axially from the distal end of the 8 ¦ housing towards the anvil and an annular stapler pushex ~
~ j projects axially from the distal end of the housing towards 10 ¦ the anvil radially outside the knife. Likewise, a suitable ~1 means, such as a cable is provided for moving the shaft into 12 ¦ the housing and, thus, the anvil towards the knife.
13 ¦ In accordance with the invention, an annular means is 14 I provided for mounting an annular stap1ing cartridge having a 15 I plurality of staples on the housing in alignment with the 16 pusher. This means includes a sleeve which is slidably 17 mounted on the housing for the movement between an extended 18 position corresponding to a retained position of the staples 19 in the cartridge and a retracted position corresponding to an expelled position of the staples from the cartridge. This 21 means also includes a mounting ring whi~ch is secured ~o and 22 ii which extends from~the sleeve concentrically about the pusher 23 ¦1 ~nd the knife for mounting of a stapling cartridge therein.
~4 il In addition, cam means aré provided for securing the 25 il sleeve relati~e to the housing during movement of the shaft and 26 111 anvil to a predetermined Point spaced from the knife so as to 27 I prevent mo~ement o~ the sleeve and thus the cartridge. Further, 28 I a cam surface is provided on the shaft at an intermediate 29 j location within the housing in order to actuate the cam means 30 I and, thus, release the sleeve for movement relative to the i1 ~ I
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1 housing in response to continued movemen~ of ~he shaft and, thus, 2 the anvil towards the knife. In this way, the anvil pushes the 3 cartridge relative ~o the pusher in order to expel the s~aples 4 of the tissue between the anvil and ~he cartridge.
The cam means may be in ~he form of a plurality of

6 circumferentially spaced balls which are mounted in the housing

7 ~or radial movPment during passage of the cam surface of the

8 shaft thereby. In this case, the cam surface may be a conical

9 annular surface located between an enlarged diameter portion of the shaft and a smaller diameter portion of the shaft.
11 The housing is formed of a pair of coaxial sections which 12 are telescopically fitted into each other with a spring between 13 one of the housing sections and the sleeve for biasing the 14 sleeve into the extended posltion. The other housing section includes a conical exterior surface while the sleeve has a 16 conical interior surface for abutting the exterior surface of 17 the housing section when in ~he extended position. The forma-18 tion of the housing into two sections facilLtates the assembly 19 of the sleeve over the housing.
The shaft is disposed wlthin the housing in a non-rotatable 21 manner. To this end, for example, the shaft is provided with at 22 least one longltudinal spllne while ~le housing is provided with 23 at least one groove receiving the spline 1n order to secure the 24 shaft against~rotation in the housing.
In addition, a releasablelock means is provided for prevent-26 ing proxima} movement of the shaf~ past a certain point in order ~7 to prevent premature firing of the staples.
28 In ordex to use the surqical stapler appaxatus, the 29 apparatus is positioned;in the usual fashion relative to two seotions of lumen which are to be joined together. After ~. . ...

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1l ne~king ,own of the ~wo sections be~ween the anvil and the cart- ' 2 l ridge, the shaft is drawn in-to the housing so that the anvil moves 3, into a position in which the two sections of tissue are clamped 4' betwePn the anvil and the cartridge. At this time, the anvil is 5' spaced and locked -at a predetermined point from the knife, i.e. a~
6 tissue gap set position, and the cartridge is positively secured 7~, against axial movement. Thereaftex, ~he lock means is ac~uated to 8,, release the shaft on which the anvil is mounted and the apparatus 9 is actuated so that the anvil is pulled fur~her ~owards the housing. The cam surface on the shaft then passes the cam means to 11, release the sleeve and the anvil, by pxessing the tissue against 12 , the cartridge, forces the cartridge to move over the pusher. The !
13 stationary staples then pierce the tissue between the cartridge 14 and anvil. W~,en the anvil has been brought to a stop, the ends of 15 I the staples will have passed through the tissue and will have beej 16 ,` clinched by the anvil to secure the two sections of tissue toge~er.
17 "I At the same time, the annular knïfe will have cut through the 18 the tissue in the usual manner.
19 1! After stapling, the anvil can be moved away from the housing 2~ , via the cable and, thereafter, the instrument can be removed in 21 the usual fashion.~ !
22 , These and other objects and advantages of the invention will 23 ~ become more apparent ~rom the following detailed description 24 taken in conjunction with the accompanying drawings wherein:
Fig. 1 illustrates a perspective view of the end of a surgic~
26 ` stapler apparatus constructed in accordance with the invention;
27 Fig. 2 il~lustrates a cross sectional view of the surgical 8 stapler apparatus of Fig. l;
25 ,` Fig. 3 illustrates a view similar to Fig. 2 with the anvil of the apparatus in a tissue gap set position space,~ from ~2'7~930 l l all allnular knife in accordance with the invention;
~ Fig. 4 illustrates a view similar to Figs. 2 and 3 with 3 the anvil in a fully retracted position in accordance with the 4 invention;
~ Fig. 5 illustrates a cross sectional view taken on line 6 V-~ of Fig. 3; and 7 Fig. 6 illustrates a view taken on line VI-VI of 8 Fig~ 4.
Re~erring to Fig. 1, the surgical stapler appaxatus 10 is ~f flexible construction. In this regard, the apparatus 11 includes an applicator portion 11 atthe distal end, an actuator 12 portion (not shown) at a proximal end And a flexible shaft 12 13 joining the applDator portion 11 and the actuator portion (not 14 shown). As indicated, the ~pparatus is used to stapl~ together two sections T of tissue of a lumen.
16 Referring tu Fig. 2, the applicator portion 11 includes 17 a housing 13 which is formed of a pair of coaxial sections 14, 15 18 which are telescopically fitted into each other. The proximal 19 housing section 14 includes an annular shoulder 16 near the proximal end for purpofies as described below while the distal 21 housing section 15 has an enlarged dlstal seotion which includes ~2 a conical exterlor surface 17.
23 The applicator porti~n 11 also has a shaft 18 which passes 24 through the housing 13 and i6 secured at the proximal end to a means such~as a flexible cable 19, which extends to the actuator 2S portion (not shownj and forms a part of the flexible shaft 12 ~or 27 moving the sha~t 18 relative to the housing 13. In addition, 28 the distal end of the shaft 18 carries an anvil 20 which is 29 removably mounted thereon by suitable means tnot shown). As indicated in Fig. 2, the shat 18 carries a central bore 21 in ~, _5_ lZ72930 wh:ich the cabl~ 19 is xeceived as well as a clinched portion 22 1 ~y which the shaft 18 is fixed to the cable 19 in a penmanent 2 manner.
3 The shaft 18 is mounted in the housiny 13 in a non-4 rotatable longitudinally movable manner. To this end, as S indicated in Figs. 2 and 5, the shaf~ 18 has a plurality of 6 circumferentially spaced axially disposed grooves 23 7 while each housing section 14, 15 has a plurality of splines 8 24 which are slidably disposed in the grooves 23 in ~ating 9 relation. The shaft 18 also has a conical annular surface 25 at an intermediate xegion within ~he distal housing portion 15 11 to separate an enlarged diameter portion 26 from a reduced 12 diameter portion 27.
13 The anvil 20 is of conventional structure and includes, 14 ~or example, two annular rows of indentations 28 for the clinching ~f staples.
16 As shown in Fig. 2, an annular knife 29 is mounted on the 17 distal end of the housing 13:and psojects axially therefrom toward 18 the anvil 20. In addition,~an annular staole pusher 30 i5 also .
19 mounted at the distal end of the housing~13 to project towards the :~
anvil 20 radially outslde the knife Z9, This pusher 30 has two 21 annular arrays of fingers 31 whi~h proj~c~ axially ~owards the 22 anvil 2~. Both the kni~fe 29 and the pusher 30 are mountzd on 23 the dis~ end of the housing portion 15 in any ~uitable manner, 24 for example~in slide-fi~ non-rotatable relation.
An annular means 32 i~ also disposed about the distal 26 end of the housing 13 in order to mount an annular stapling 27 cartridge 33 cont~ning, for example, two annular rows of 28 staples 34 ln alignment with the pusher fingers 31. This 29 annular means~32 includes a mounting ring 35 and a sleeve 36.
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lZ7;~3 [) 1 ! ~ne mounting ring 35 *ncircles the distal end of the 2 housing 13 and covers over the pusher 30 and knife 29. In 3 addition, the cartridge 33 is stepped, as shown, at the distal 4 end so as to be fitted within ~he ring 35 while forming a S smooth continuation of the outer surface of the ring 35.
6 The sleeve 36 has the ring 35 slidably mounted thereon 7 in suitable fashion. In addition, the sleeve 36 is contoured 8 to slidably fit over the two housing sections 14, lS and ha~
9 an internal conical surface 37 facing the external conical surface 17 of the distal housing section 15. When in the 11 position illustrated in Fig~ 2, the conical surface~ 37, 17 12 abut each other.
13 ~s shown ln Fig. 2, a spring, such as a compression 14 spring 38, is disposed between the end of the proximal housing section 14 and the sleeve 36 in order to bias the sleeve 36 in a 16 distal direction. Further, the sleeve 36 is provided~with a 17 plurality of radial ports 39 which serve to vent the 18 space between the sleeve 36 and the distal housing section 15.
19 Referring to Figu 2, a cam means 40 is provided for securing the sleeve 36 re}ative to the housing 13 during 21 movement of the anvil 20 to a predetermined point (see Fig. 3) 22 spaced ~rom~the knife 29. The cam means 40 cooperates with the 23 conical annular surface 25 of the shaft 18 which, thus, acts as a 24 cam surface, and~is positioned relative to the sleeve 36 for movement relative to ~he housing 13 in response to contlnued 26 movement of the anvil 20 towards the knife 29 (see Fig. 4) whereb 27 the anvi~l 20 is abls to push the cartridge 33, mounting ring 35 2~ and sleeve 36 relative to the pusher 30 in order to expel the 29 staples 34 from the cartrid~e 34. As illustrated, the cam means 40 lncludes a plurality of cir~umferentially spaced ., 127;293{) 1 latches in the form ~f bal~s 41 which are -rnounted in radial bores 42 2 in the proximal housing section 11 in a cage-like manner for 3 radial movement during passage of the annular cam surface 25 4 thereby. In addition, the cam means 40 includes an inclined cam surface 43 on the sleeve 36 and a cylindrical surface ~4 6 which extends proximally from the ca~ surface 43. As indicated 7 in Fig. 2 which represents the extended position of the sleeve 36 8 and mounting ring 35, the balls 41 are positioned ~etween and are 9 in contact with the enlarged diameter portion 26 of th,e shaft 18 and the cam surface 43 of the sleeve 36 at the point where the 11 cylindrical surface 44 merges into the cam ~urface 43. In 12 this position, the shaft 18 can be moved in a distal or proximal 13 direction relative to t~e housing 13 so that the balls 41 merely 14 ride on the enlarged diameter portion 26 of the shaft 18. However the sleeve 36 i~ prevented from moving in a proximal direction 16 relative to the housing 13 since the balls 41 otherwise jam 17 the sleeve 36 against such a movement.
18 Referring to Fig. 3, when the ~haft 18 is moved in the 19 pxoximal direction relative to the:~ousing~13, the cam surface 25 of the shaft 18 is brought into a position to permit the balls 41 21 to begin to move radially inwardly.~ Thereafter, if the shaft 18 22 and the sleeve 36 move~proximally relative to the housinq 13, the 23 ~alls 41 are able to move radially inwardly by riding along the 24 "inner"~cam surface 25 and the "outer" cam surface 43 (see Fig. 4 and Fig. :6). Thus, the position illustrated in Fig. 3 26 indlcates~a position :in which the sleeve 36 is released ~or 27 axial proximal movement relatlve ~o the housiny 13.
28 Referrlng to:Fig.~3, in order to prevent inadvertant .
29 proximal movement of the sleeve 36 and, thus, a premature firing of the staples 34, a releaseable lock means 45 is pravided to :' -8-' . ~ ' . .

~1~72930 1 pre~ent proximal movemen~ of the shaft 18 past a certain point.
~ As shown, the lock means 45 includes a latch 46 which is 3 pivotally mounted on a fixed pivot pin 47 within a suitable 4 ~ecess 48 in the proximal housing section 14. This latch 46 has a hooked end 49 which i6 sized to abut the proximal end 6 of the shaft 18 when the shaft 18 moves proximally, e.g. from 7 the position shown in Fig~ 1 to the position shown in Fig. 3.
8 A spring 50 is also provided to bias the latch 46 into the 9 locking position shown.
In order to release the latch 45, a cam means 51 in the 11 form of a ball engages between an inclined cam surface 52 at a 12 distal end of the latch 45 and a wall of the rec~ss 48. In 13 addition, a cable 53 passes through the ball 51 in fixed 14 relation and extends o~er a guide pin 54 in the recess 48 and ~hrough the flexible shaft 12 to a point e.g. at a proximal end 16 of the applicator portion 11. m e proximal end of the~cable 53 17 is mounted in a manner to be pulled by a surgeon in order to lB release the latch 45. In this regard, pulling of the cable 53 19 causes the ball 51 to move proximally which, in turn, pivots thè latch 45 counter-clookwise, as viewed, from ~he Iocking 21 position to a release position with the hooked end 49 out of 22 the path of the shaft 18.
23 Referring to Fig~ 4, the flexible shaft 12 includes a 24 1exible axially rigid tube 55 o~ conventional construction which extends from the actuator portion (not shown) about the 26 cable 19 to the housing 13 of the applicator portion 11. As 27 indioated, the tube 55 abuts against the annular shoulder 16 of 28 the proximal housing section 14 so as to retain the housing 13 29 in a stationary manner relative to the actuator por~ion (not shown). Other suitable means (not shown) may also be provided _g_ .' i~o 1 in abu~men~ with the proximal end of the housing 13 in order to ~ main~ain the housing 13 sta~ionary relative ~o the applicator 3 portion 11.
4 As indicated in Fig. 2, the applicator por~ion 11 is in an S open position. As this time, the sleeve 36 is in an extended 6 position and the staples 34 are in a ra~ain~d position within the 7 cartrid~e. In addition, ~he shaft 18 i5 free to move axially 8 while the balls 41 lock the sleeve 36 relative to the housing 13.
9 In operation~ the surgical stapler appa~atus 10 i5 inserted into the lumen of two tissue sections T which-are to be draw~
11 together. After necking down of the two sections T between the 12 anvil 20 and the cartridge 33 as shown in the open position 13 of Fig. 2, the shaft 18 is drawn into ~he housing 13 by pulling 14 on the cable 19 via suitable linkages in the actuator portion (not shown) as is known. This movement proceeds with the anvil 16 20 moving into a predetermined position spaced from the cartridge 17 33, for example by a distance of 1 ~o 1.5 millimeters. ~In ~his 18 tissue gap set position, as shown in Fig. 3, the two sections of 19 tissue T are olamped between the anvil 20 and the cartridge 33.
In addition, the sha~t 13 abuts against the hooked end 49 of 21 the spring bias6d latch 45 and lS locked against further 22 proximal movement together with the sleeve 36.
23 ~Next, the surgeon pulls on the proximal end of the 24 cable 53 to pivot the latch 46 and, thus, release the shaft 18 for further movement.

26 ; ~hereafter, the surgeon actuates the apparatus 10, for 27 example~by triggering a pistol grip or handle (not shown) in 28 the actuator position 11 which is linked to the cable 19 in 29 a suitable manner (not shown) in ord6r to pull the cable 19 and, thus, the shaft 18 proximately a short distance. In this way, ' ~ -10- ' : :
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127Z~330 1 a~ the shaf~ 18 is thus pulled in ~he proximal direction, the 2 anvil 20 is pulled towards the housing 13~ At this time, 3 the anvil 20 presses the clamped tissue T against the cartxidge 9 33 and, thus, forces the cartridge 33 to move over ~he pusher 30.
~lso, at this time, the balls 41 begin to mo~e radially inwardly 6 under the camming action of the cam surface 43 of the sleeve 36 7 against the bias of the spring 38. Continued motion causes the 8 stationary s~aples ~4 to pierce the tissue T. As indica~ed-~n 9 the fired position of Fig. 4, when the anvil 20 has been brought to a stop, the ends of the staples 34 will have passed through 11 the tissue T and will have been clinched via ~he indentations 28 12 on the anvil 20 so as to secure the two sections of tissue 13 together.
14 During the stapling action, the annular knife 29 cuts the inner circumferential edges of the tissue T in the usual 16 fashion.
17 After stapling, the applioator portion (not shown) is 18 actuated in a conventional manner to move the sha~t 18 and 19 anvil 20 distally so as to unclamp the stapled tissue joint and thereafter the stapler apparatus 10 is removed form the lumen.
21 The cam means 40 for preventing movement of the cartridge 22 33 relative to the staples 34 until stapling action is required 23 is of relatively simple reliable construction. In this reqpect, 24 the position (i.e. tissue gap) a~ which the anvil 20 is initially brought into a predetermined spaced position from the 26 staple cartridge 33 can be easily and precisely determined by 27 the construction of the various components of the applicator 28 portion ll. ~
29 The spring 38 may be of any suitable strength so as to lnitially bias the~sleeve 36 against the conical exterior surface .: ~ ' ' 1~272930 1 1~ ~ the housing section 15 while a~ the same time being of a 2 ~eak stxength to permit ~he anvil 20 to move the cartridge 33 3 proximally via the clamped tissue T. That is, the strength 4 D~ ~he spring 38 should no~ be such ~hat the anvil 20 would crush the tissue T.
6 O~ note, when ~he anvil 20 is moved away from the 7 stapled tissue, the cam surface 25 on the shaft 18 begins to bias 8 the balls 41 radially outwardly. Thus, the balls 41, in tu~n, 9 serve to push to sleeve 36 distally relative to the housing 13 along with the biasing force produced by the spring 38. In 11 addition, as the anvil 20 is moved distally, the latch 45 is 12 spring biased back into the locking position behind the shaft 18.
13 ~he surgical stapling apparatus 10 is preferrably 14 actuated in a single step manner as described above but may also, be constructed =o that the anvil 20 moves in ~wo stages from 16 ~he open position shown in Fig. 2 to the tissue gap set position 17 shown in Fig. 3 and then to~the fired position shown in Fig. 4.
18 The invention thus provldes a flexible surgical st=pler 19 apparatus wherein an anvil can be moved relative to a stapling cartridge in a relatively simple easy-to-use and reliable manner.
21 Further, the invention provides an end-to-end anastomosis 22 stapler =pp=r=tus of simple construction.

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Claims

What is Claimed is:

1. A surgical stapler apparatus comprising a housing;
a shaft movably mounted in said housing for relative longitudinal movement therein, said shaft having a cam surface at an intermediate location within said housing;
an anvil mounted on a distal end of said shaft;
an annular knife projecting axially from a distal end of said housing towards said anvil;
an annular staple pusher projecting axially from said end of said housing towards said anvil and radially outside said knife;
annular means for mounting an annular stapling cartridge having a plurality of staples on said housing in alignment with said pusher, said means including a sleeve slidably mounted on said housing for movement between an extended position and retracted position;
means for moving said shaft into said housing and said anvil towards said knife; and cam means for securing said sleeve relative to said housing during movement of said anvil to a predetermined point spaced from said knife, said cam means being positioned relative to said cam surface on said sleeve for movement relative to said housing in response to continued proximal movement of said anvil towards said knife from said point whereby said anvil pushes said annular means relative to said pusher to expel staples from a stapling cartridge thereon for stapling of tissue between said anvil and a cartridge on said annular means.

2. An apparatus as set forth in claim 1 wherein said cam surface is a conical annular surface and said cam means includes a plurality of circumferentially spaced balls mounted in said housing for radial movement during passage of said cam surface thereby.

3. An apparatus as set forth in claim 1 wherein said housing includes a pair of coaxial sections telescopically fitted into each other and which further includes a spring between one of said housing sections and said sleeve for biasing said sleeve into said extended portion.

4. An apparatus as set forth in claim 3 wherein the other of said housing sections includes a conical exterior surface and said sleeve has a conical interior surface for abutting said exterior surface in said extended position.

5. An apparatus as set forth in claim 1 wherein said annular means includes a cartridge mounting ring secured to and extending from said sleeve concentrically about said pusher and said knife.

6. An apparatus as set forth in claim 5 wherein said pusher is an annular ring having at least one annular row of fingers for pushing a row of staples from a cartridge mounted on said ring.

7. An apparatus as set forth in claim 1 wherein said pusher is an annular ring having at least one annular row of fingers for pushing a row of staples from a cartridge mounted on said annuluar means.

8. An apparatus as set forth in claim 1 wherein said means for moving said shaft is a flexible cable secured to a proximal end of said shaft.

9. An apparatus as set forth in claim 1 which further comprises a releaseable lock means for preventing proximal movement of said shaft past a certain point.

10. An apparatus as set forth in claim 9 wherein said lock means includes a pivotally mounted latch in said housing having a proximal end to abut said shaft, cam means for pivoting said latch from said shaft and a cable extending from said cam means for moving said cam means to release said latch.

11. An apparatus as set forth in claim 1 which further comprises at least one groove in said shaft and at least one spline on said housing receiving said spline to secure said shaft against rotation in said housing.

12. A flexible surgical stapler apparatus comprising a housing;
a non-rotatable shaft slidably mounted in said housing;
a flexible axially rigid tube abutting said housing;
a cable within said tube and secured to said shaft for moving said shaft relative to said housing;
an anvil mounted on a distal end of said shaft;
an annular knife projecting from a distal end of said housing towards said anvil;
an annular staple pusher projecting from said distal end of said housing towards said anvil;
an annular stapling cartridge having a plurality of staples mounted in alignment with said pusher for stapling tissue disposed between said anvil and said cartridge;
a mounting ring concentric to and about said pusher mounting said cartridge thereon, said ring being movable between an extended position and a retracted position; and means for securing said ring relative to said housing during movement of said anvil to a predetermined point spaced from said knife and for releasing said ring from securement with said housing in response to continued movement of said anvil towards said knife whereby said anvil pushes the tissue and said cartridge towards said pusher to expel said staples from said cartridge while pushing said staples through the tissue and against said anvil for clinching thereof.

13. An apparatus as set forth in claim 12 which further comprises a sleeve movably mounted about said housing with said ring at a distal end thereof and said means includes a plurality of balls mounted in said housing for radial movement, an annular cam surface on said sleeve in contact with said balls in said extended position of said mounting ring and an enlarged diameter portion on said shaft in contact with said balls in said extended position to secure said sleeve against axial movement.

14. An apparatus as set forth in claim 13 wherein said means includes a cam surface on said shaft at a distal end of said enlarged diameter portion to permit radial inward movement of said balls during movement of said can surface thereby to simultaneously release said sleeve for axail movement relative to said housing.

15. An apparatus as set forth in claim 14 which further comprises a spring between said housing and said sleeve biasing said sleeve in a distal direction.

16. An apparatus as set forth in claim 14 wherein said housing includes a pair of coaxial sections telescopically fitted into each other and which further includes a spring between one of said housing sections and said sleeve for biasing said sleeve in a distal direction.

17. An apparatus is set forth in claim 12 which further comprises a releaseable lock means for preventing proximal movement of said shaft past a predetermined point.

18. An apparatus as set forth in claim 17 wherein said lock means includes a latch pivotally mounted in said housing to abut said shaft, cam means for pivoting said latch from said shaft and a cable extending from said cam means for moving said cam means to release said latch.

19. An apparatus as set forth in claim 22 which further comprises at least one spline on said housing receiving said spline to secure said shaft against rotation in said housing.

20. An apparatus as set forth in claim 12 which further comprises a sleeve movably mounted about said housing with said ring at a distal end thereof, said sleeve having an internal surface abutting an external conical surface of said housing in said extended position of said ring and a spring between said housing and said sleeve biasing said sleeve against said external surface.

21. An apparatus as set forth in claim 20 wherein said means includes at least one latch mounted in said housing for radial movement, a cam surface on said sleeve in contact with said latch in said extended position of said ring and an enlarged diameter portion on said shaft in contact with said latch in said extended position to secure said sleeve against axial movement.

22. An apparatus as set forth in claim 21 wherein said means includes a cam surface on said shaft at a distal end of said enlarged diameter portion to permit radial inward movement of said latch during movement of said cam surface thereby to simultaneously release said sleeve for axial movement relative to said housing.

23. An apparatus as set forth in claim 20 wherein said housing includes an annular shoulder abutting said tube and positioned for abutting of said sleeve thereon in said retracted position of said ring.

24. An apparatus as set forth in claim 20 wherein said sleeve has a plurality of radially disposed apertures for venting a space between said sleeve and said housing.

25. In a surgical stapler apparatus the combination comprising a housing:
a shaft movably mounted in said housing for relative longitudinal movement therein;
an anvil mounted on a distal end of said shaft;
an annular stapler pusher projecting axially from a distal end of said housing towards said anvil;
means for mounting an annular stapling cartridge on said housing in alignment with said pusher, said means including a sleeve slidably mounted on said housing for movement between an extended position and retracted position;
means for moving said shaft into said housing and said anvil towards said knife; and cam means between said housing and said sleeve for securing said sleeve relative to said housing during proximal move-ment of said anvil to a predetermined point relative to said housing, said cam means being positioned relative to said sleeve for movement relative to said housing in response to continued proximal movement of said anvil from said point whereby said anvil pushes said annular means relative to said pusher to expel staples from a stapling cartridge thereon for stapling of tissue between said anvil and a cartridge on said housing.

26. An apparatus as set forth in claim 25 wherein said shaft has a cam surface at an intermediate location within said housing and said cam means includes at least one ball mounted in said housing for radial movement during passage of said cam surface thereby.

27. An apparatus as set forth in claim 25 wherein said housing includes a pair of coaxial sections telescopically fitted into each other and which further includes a spring between one of said housing sections and said sleeve for biasing said sleeve into said extended portion.

28. An apparatus as set forth in claim 27 wherein the other of said housing sections includes a conical exterior surface and said sleeve has a conical interior surface for abutting said exterior surface in said extended position.

29. An apparatus as set forth in claim 25 which further comprises a pivotally mounted latch in said housing having a proximal end to abut said shaft to prevent proximal movement of said shaft from said point, cam means for pivoting said latch from said shaft and a cable extending from said cam means for moving said cam means to release said latch.