DISPOSABLE SURGICAL STAPLER

Abstract: A surgical stapling instrument of the type having a pair of separable body parts (30, 31) respectively providing handle halves (33) and staple cartridge anvil supporting jaws (34, 36) with a locking lever (32) for clamping the body halves together prior to staple ejection. The body halves are of plastics material and are strengthened by an embedded steel rib extending through part of the handle portion and the entire cartridge or anvil supporting portion. The clamping lever (32) is locked in its closed position by a positive locking arrangement (65) at the rear of one of the body halves (31).

Description: DISPOSABLE SURGICAL STAPLER TECHNICAL FIELD This invention relates to surgical stapling instruments of the type comprising a manually operated drive mechanism by means of which staples are ejected from a staple cartridge against an anvil through intervening tissue, in surgical suturing procedures. BACKGROUND ART One example of this type of instrument is described in United States patent 3,499,591 which discloses an instrument for placing lateral gastrointestinal anastomoses which consists of separable upper and lower jaw frames each having a forward projection, these projections respectively accommodating a staple cartridge and a disposable anvil. In the use of such an instrument, after loading of a staple cartridge in the forward projection of the upper jaw frame, and the mounting of an anvil on the forward projection of the lower jaw frame, the two halves of the instrument are assembled by engaging a hinge connection between the upper and lower jaw frames at the rearward end of the instrument, bringing the frames together with the tissue correctly positioned between the opposed forward projections, and locking the jaw frames together by means of a clamping lever pivotally attached to the lower jaw frame, after which the stapling operation is carried out by pushing forwardly within an elongated slot in the upper jaw frame, a handle which functions to drive forwardl within the staple cartridge a pair of staple ejecting pusher cams and a central knife edge, the latter severing tissue between the rows of staples ejected from the cartridge. The clamping lever is removably engaged with the lower jaw frame by the engagement of a slot in the locking lever with a press fitted pin which passes between the outer walls of the lower jaw frame, and is provided at its inner end with a hinge pin which is engaged within a pair of slots provided in the walls of the upper jaw frame. fREX The locking lever is retained in its closed position during a stapling operation by means of a leaf spring mounted on the lower jaw frame, which leaf spring must be depressed to release the locking lever upon completion of a stapling operation. The instrument disclosed in U.S. patent 3,499 ,591 will be referred to herein as "the prior art instrument". The prior art instrument suffers from several disadvantages. Although when the clamping lever is released and moved to its open position the ' jaws of the instrument are free to be opened as widely as desired in order to release the instrument from the stapled tissue, yet the action of the clamping lever and its pin-and-slot engagement with the upper and lower jaw frames is such that it clicks into a fixed open position, and it is found that this limited opening action of the locking lever does not encourage the surgeon to open the jaws of the instrument any wider than they are automatically opened when the locking lever is moved to its fixed open position. In cases where a considerable thickness of tissue has been stapled, this may lead to tissue remaining jammed in the jaws such that removal of the instrument may cause tearing or other damage to the tissue. Furthermore it is found that the leaf spring catch employed to retain the locking lever in its closed position provides insufficiently positive locking, such that if the jaws of the instrument are over¬ loaded upon closure, for example where the tissue thickness exceeds the limits of the instrument, the locking lever may be released by the leaf spring and returned to its open position. Again in the case of large tissue thickness when the instrument is locked with high pressure on the jaws it is difficult or at times impossible to release the spring catch by pressure with the thumb as is intended. A further disadvantage of such a known instrument is that it has hitherto been necessary to manufacture the instrument entirely of steel so that it is not practical to manufacture such an instrument at a cost which enables it to be disposed of after one or only a few uses. The instruments therefore require repeated sterilisation and inevitably suffer from corrosion and wear after repeated uses. DISCLOSURE OF INVENTION It is an object of the present invention to provide a clamping arrangement for a surgical stapling instrument of this type which offers the advantages of greater simplicity of operation and greater security of locking in use, and which operates in a manner which ensures the full release of tissue after a stapling operation. It is a further object of the present invention to provide such an instrument which is largely constructed of plastics material and is therefore more readily disposable. The invention broadly resides in a surgical stapling instrument comprising first and second members each comprising a handle portion and a nose portion, said nose portions being respectively adapted for the reception of a staple cartridge and a staple forming anvil, said members being adapted for detachable hinged connection in the region of the ends of said handle portions remote from said nose portions, and a clamping lever adapted for pivoting connection to one of said members and engageable with the other of said members to clamp said members together, characterised in that each said member comprises a body of plastics material and a metal rib, said rib being structurally associated with said body and extending substantially throughout the length of said nose portion and over a substantial length of said handle portion. The invention will now be described in relation to a presently proposed embodiment which it will be understood is given by way of example only and comprises many features of construction which are not themselves essential characteristics of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows in side elevation of a surgical stapling instrument embodying the present invention. Figure 2 shows in side elevation the upper jaw member of the instrument illustrated in Figure 1, Figure 3 is an underneath plan view of the upper jaw member of Figure 2, Figure 4 is a side elevation of the lower jaw member of the instrument of Figure 1, Figure 5 is a plan view of the lower jaw member of Figure 4, Figure 6 is a side elevation of the reinforcing member of the upper jaw member of Figure 2, Figure 7 shows in side elevation the reinforcing member of the lower jaw member of Figure 4, Figure 8 shows * in side elevation the clamping lever of the instrument of Figure 1, Figure 9 is an end elevation of the clamping lever of Figure 8, Figure 10 is a plan view of one of the side walls of the lever of Figure 8, Figure 11 is a cross-section taken at 11 in Figure 2, Figure 12 is a corresponding cross-section taken at 12 in Figure 4, Figure 13 is a cross-section taken at 13 in Figure 2, Figure 14 is a corresponding cross-section taken at 14 in Figure 4, Figure 15 is a cross-section taken at 15 in Figure 2, Figure 16 is a corresponding cross-section taken at 16 in Figure 4, URIZ Figure 17 is a cross-section taken at 17 in Figure 2, Figure 18 is a corresponding cross-section taken at 18 in Figure 4, Figure 19 is a cross-section taken at 19 in Figure 2, Figure 20 is a corresponding cross-section taken at 20 in Figure 4, Figure 21 shows in plan view the locking slide of the instrument of Figure 1 , and Figure 22 is a side elevation of the locking slide of Figure 21. DESCRIPTION OF PREFERRED EMBODIMENT The instrument illustrated in the drawings comprises an upper jaw member 30, a lower jaw member 31 and a clamping lever 32. The upper jaw member consists of a handle portion 33 and a forward projection 34, and is of generally U-shaped cross-section. As shown in Figure 11 the forward projection 34 is provided with a slot 35 for the reception of a staple cartridge of a type similar to the cartridge employed with the instrument described in the above-mentioned U.S. patent 3,499,591. The lower jaw member 31 is similarly of generally U-shaped cross- section and is provided with a forward projection 36 which is formed for the reception of a disposable anvil in a manner similar to that described in the above-mentioned patent. Each of the jaw members 30 and 31 is formed of plastics material. ' In order that this may be done while still enabling the application of sufficient force between the staples and anvil, each of the upper and lower jaw members 30 and 31 is provided with a steel reinforcing plate 37 and 38 respectively, these being individually illustrated in Figures 6 and 7. The plates 37 and 38 are contoured in side elevation to lie centrally of their respective jaw members and each extends from the forward extremity of the respective forward projections 34 and 36 to the rear portion of each of the jaw members, as shown particularly in Figures 3 and 5. Plate 37 is mounted with its upper OMP longitudinal edge embedded within a slot extending longitudinally in the inner surface of the upper wall 39 of the handle portion 33 of the upper jaw member 30, as shown particularly in Figures 13, 15 and 17, and its forward end 40 extends through the front 41 of the handle portion 33 and is embedded within a slot in the outer surface of the forward projection 34 of the upper jaw member, with its upper edge exposed outwardly of the portion 34, as shown in Figure 11. The reinforcing plate 38 is similarly embedded within a slot formed in the inner side of the bottom wall of the lower jaw member 31 as shown in Figures 14, 16 and 18, and similarly passes through the front wall 42 of the lower jaw member 31 to a forwardly extending portion 43 located in a slot formed in the lower surface of the forward projection 36, as shown in Figure 12. It will be appreciated that the plates 37 and 38 stiffen the plastics jaw members 38 and 40 against bending, and the forward reinforcing plate portions 40 and 43 provide the necessary rigidity for the correct mounting and operation of the disposable cartridge and anvil. The reinforcing plates 37 and 38 are apertured at 44 and 45 for the reception of pins 46 and 47 by which these plates are fixed to their respective jaw members, these pins 46 and 47 respectively passing through the side walls 48 and 49 of the upper jaw member 30 and the sidewalls 50 and 51 of the lower jaw member 31. Depending from each of the side walls 48 and 49 of the upper jaw member 30 is downwardly extending lug 52 on each of which is integrally provided a laterally outwardly extending pin 53. The clamping lever 32, which may be made of pressed metal, is of U-shaped cross-section as shown in Figure 9, having a web portion 54 and a pair of side walls 55 which extend forwardly past the web 54 to form a contoured locking portion 56 terminating in a nose 57. Penetrating each of the side walls 55 rearwardly of the nose portion 57 are coaxial apertures 58 for the reception of a pivot pin (not shown) which also passes through a pair of coaxial apertures 59 in the side walls 50 and 51 of the lower jaw portion 30. The clamping lever ΓRI 32 is thereby pivotally attached to the lower jaw member 31. The pivot pin is suitably fixed in this position, for example by means of a head and nut which bear against the external surfaces of the side walls 50 and 51. Depending downwardly from the lower edge of the rearmost portion of the upper handle portion 33 is a lug 60 on the side surfaces of which are provided coaxial pins 61 of circular cross-section. In the side walls 50 and 51 at the rearmost portion of the lower jaw member 31 there are provided longitudinally and vertically co-extensive slots 62 which are dimensioned to receive the pins 61. The instrument thus far described is assembled as follows. The clamping lever 32 is fixed to the lower jaw member 31 by means of the pivot pin, a staple cartridge is engaged with the forward projection 34 of the upper jaw member 30 and an anvil is engaged with the forward projection 36 of the lower jaw member 31. The rear ends of the upper and lower jaw members 30 and 31 are then brought together such that the pins 31 enter the slots 62 and with the clamping lever 31 in its open position as illustrated in the solid lines of Figure 1, the upper and lower jaw members 30 and 31 are brought together with the tissue to be sutured appropriately positioned between the cartridge and anvil. The clamping lever 32 is then brought to its closed position as shown by the broken lines of Figure 1, the side walls 55 of the clamping lever 32 straddling the side walls 50 and 51 of the lower jaw member 31. As the clamping lever 32 rotates to its closed position the nose 57 rotates towards the pins 53 and engages with these pins thereby drawing together the forward projections 34 and 36 and clamping the tissue between the cartridge and anvil. The clamping lever 32 is releasably fixed in its closed position by a locking arrangement which comprises a pair of longitudinally co- extensive slots 63 in the side walls 50 and 51 of the lower jaw member 31 through which passes a locking plate 64 (Figures 21 and 22) the longitudinal dimension of which is less than the length of the slots 63. The locking plate 64 projects outwardly beyond each of the side walls 50 and 51 and provided on the exposed surfaces of the plate 64 on each side of the lower jaw member 31 are a pair of actuating plates 65. The locking plate 64 is assembled with the actuating plates 65 by first passing the plate 64 through the slot 63 and then attaching the plates 65 to it by means of pins 66 and correspon- ding blind holes 67 as shown in Figure 22. It will be observed (Figure 21) that the locking plate 64 extends forwardly of the foremost extremity of the actuating plates 65, and is provided with a radiused forward end 68. A pair of slots 69 are provided centrally of the rear edge of the side walls 55 of the clamping lever 32 and these slots 69 are located such that in the fully closed position of the clamping lever 32, they lie on the axis of the slots 63 so that when the clamping lever 32 is moved to its fully closed position the locking plate 64 may be slid forwardly by pressure of the thumb on either side of the actuating plates 65, whereupon the end portion 68 of the locking plate 64 enters the slots 69, locking the clamping lever 32 in its closed position in a positive manner. The staple and cutting blade driving mechanism is not shown in the drawings, and may be constructed in a manner similar to that described in the prior art instrument. It will be observed than an elongated slot 70 having an enlarged rear portion 71 is provided in the side wall 49 of the upper jaw member 30 for the mounting of a pusher assembly in a manner similar to that described in the prior art instrument. The function of features of the instrument illustrated in the drawing but not specifically mentioned in the preceding description, such as side slots 72 provided in the mid portion of the sides of the forward projection of the lower jaw member for mounting the anvil, and the longitudinal slot 73 in the upper surface of the projection 36 for the reception of the cutting blade, will be apparent to persons familiar with the prior art instrument. After the completion of a stapling operation the instrument is released from the stapled tissue by moving the locking plate 63 rearwardly by means of thumb pressure against one of the actuating plates 65 to release the rear end of the clamping lever 32, and moving this lever to its fully opened position. In view of the fact that such movement fully releases the upper and lower jaw members 30 and 31 as each nose 57 moves clear of the pins 53, there is no encouragement for the surgeon to leave the upper and lower jaw members in the partially engaged position in which they remain in the prior art instrument without further manipulation. As will have been observed, with the exception of the reinforcing plates 37 and 38 and the clamping lever 32, the entire instrument is constructed of plastics material and is readily disposable. It is found that the reinforcing plates 37 and 38 provide sufficient rigidity for adequate force to be applied between the cartridge and the anvil without undue bending of the forward projections 34 and 36. As in the prior art, these projections are pre-set to taper inwardly towards each other at their forward end so that their opposed surfaces are substantially parallel in operation of the instrument. O PI

Claims: CLAIMS 1. A surgical stapling instrument comprising first and second members each comprising a handle portion and a nose portion, said nose portions being respectively adapted for the reception of a staple cartridge and a staple forming anvil, said members being adapted for detachable hinged connection in the region of the ends of said handle portions remote from said nose portions, and a clamp¬ ing lever adapted for pivoting connection to one of said members and engageable with the other of said members to clamp said members together, characterised in that each said member comprises a body of plastics material and a metal rib, said rib being structurally associated with said body and extending substantially throughout the length of said nose portion and over a substantial length of said handle portion. 2. A surgical stapling instrument according to claim 1, further characterised in that at least one of said members is substantially U-shaped in lateral cross-section having a bight portion and a pair of flanges, said rib of said at least one member being embedded along one longitudinal edge within said bight portion. 3. A surgical stapling instrument according to claim 2 further characterised in that said member is embedded along one first longitudinal edge within the bight portion of said handle portion, and along its opposite longitudinal edge within the bight portion of said nose portion. 4. A surgical stapling instrument according to claim 1 further characterised in that said clamping lever comprises a portion extending forwardly of the point of its pivotal connection with said one member, said forwardly extending portion engaging means on said other member to draw said members together upon closing of said lever. - n - 5. A surgical stapling instrument according to claim 4 wherein said lever further comprises a handle portion extending rearwardly from its pivoting connection, the rearward end of said lever being provided with means co-operating with locking means at the rear of said first member to enable said lever to be locked in its clamping position. 6. A surgical stapling instrument according to claim 5 further characterised in that said locking means comprises a locking slide movable relative to said first member between a locking position and a free position, said slide being provided with means engaging a slot in the rear end of said lever. ^UREA OMPI

Inventors: CIABATTI A, CRISPE L, DIPPERT M, LEMCKE V
Applicants: CIABATTI A, CRISPE L, DIPPERT M, HOSPITAL PROD LTD, LEMCKE V
Application year: 1981
Main classification: B25C5
IPC codes: A61B17