SURGICAL STAPLER DRIVE MECHANISM

Abstract: A surgical stapling instrument in which single-handed operation and relative disposability are achieved by the use of a toggle actuated (24, 25, 26, 34) staple drive mechanism and the use of plastics material (10) in non-load-carrying body parts.

Description: « SURGICAL STAPLER DRIVE MECHANISM 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 and through intervening tissue, in surgical suturing procedures. BACKGROUND ART Instruments of this type are now well known and widely used in surgery. Examples of such instruments are described in U.S. patent 3,494,533 and West German published patent application 28 22803, the former describing the instrument for the lateral anastomosis of body organs, the latter describing the instrument for the end-to-end anastomosis of organs. The drive arrangement employed in such instruments consists of a pair of operating handles, one fixed and one movable, the movable handle driving a staple pusher by means of a simple lever action. It is sometimes found that with such a drive mechanism insufficient staple- driving force can be developed by operation of the instrument with one hand, particularly when stapling through large thicknesses of tissue. In such situations the surgeon must resort to the use of both hands, which is difficult both in view of the fact that the operating handles are not designed to accommodate both hands, and also in view of the fact that the hands may not be as steady in such a position, particularly when great force is being applied to the instrument. A further disadvantage of the known instruments of this type is that they are manufactured entirely from stainless steel and are not disposable, and yet suffer from corrosion and damage after repeated use, and of course require sterilisation before re-use. DISCLOSURE OF THE INVENTION An object of the present invention is therefore to provide a mechanism which provides greater ease of one-handed operation. A further object of the invention is to provide a drive mechanism which enables a large proportion of the instrument to be manufactured in plastics material, so that it is light, inexpensive and disposable, thereby eliminating the need for subsequent steril sation and the problem of corrosion. The invention broadly resides in a surgical stapling instrument comprising opposed jaws respectively adapted for carrying an anvil and a staple cartridge and means for ejecting staples from said cartridge against said anvil, adjustment means extending longitudinally of the instrument and longitudinally movable to vary the separation of said anvil and said cartridge, staple ejection actuating means extending longitudinally of the instrument and longitudinally movable to drive said ejection means, characterised in that said instrument further comprises a housing supporting the rearward portions of said adjustment means and said actuating means and an operating handle pivotally mounted at the forward end of said housing, said handle being connected to said actuating means by a toggle thereby to drive said actuating means in its staple-ejecting direction upon closure of said handle towards said housing. By the adoption of such a configuration, it is possible to employ plastics materials for the housing and other components not subjected to the main staple driving forces, and to provide a configuration of the housing and operating handle which facilitates one-handed operation while achieving sufficient staple actuating force. The invention will now be described in relation to two presently proposed embodiments which it will be understood are given by way of example only and comprise many features of construction which are not themselves essential characteristics of the invention. The instrument illustrated by way of example in Figures 1 to 6 is of the type employed in end-to-end anastomosis, for example, anastomosis of proximal and distal bowel sections in low anterior resection, while the instrument illustrated, again by way of example, in Figures 7 to 11, is of the type normally used for the closure of organs. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a cross-sectional side elevation of a surgical stapling instrument embodying the present invention; - Figure 2 shows a lateral cross-section of the instrument of Figure 1 taken at 2 in Figure 1; Figure 3a shows a lateral cross-section taken at 3 in Figure 1 with the operating handle in its open position; Figure 3b shows a lateral cross-section taken at 3 in Figure 1 with the operating handle in its • closed position; Figure 4 shows a lateral cross-section taken at 4 in Figure 1 ; Figure 5 shows a lateral cross-section taken at 5 in Figure 1 ; Figure 6 shows a section taken on the line 6-6 in Figure 1 ; Figure 7 shows a cross-sectional side elevation of a second surgical stapling instrument embodying the present invention; Figure 8 shows a cross-sectional plan view of the instrument of Figure 7; Figure 9 shows a cross-sectional view taken at 9 in Figure 7; Figure 10 shows a cross-sectional view taken at 10 in Figure 7; Figure 11 shows a cross-sectional view taken at 11 in Figure 7. DESCRIPTION OF PREFERRED EMBODIMENTS The instrument illustrated in Figure 1 comprises a cylindrical body 10 of plastics material which is open at its rear end for the reception of a gland nut 11 within which there is mounted for rotation an adjusting nut 12 which is fixed against axial movement by a circlip 13 and shoulder 14. The forward end of the instrument is adapted for the mounting, on an extended forward tubular body portion 15, of a circular cartridge and knife blade assembly shown in outline at 16, and of a circular anvil 17 by means of a screw 18 to the outer end of a steel inner shaft 19. The cartridge and knife assembly 16 and the anvil 17 may be constructed in a manner similar to the corresponding elements described in German published patent application 2822803 referred to above, and in the following description it will be assumed that the reader is familiar with the manner of operation of that instrument. The inner end of the inner shaft 19, which is made of stainless steel, is connected with the adjusting nut 12 by means of a threaded rod 20. Surrounding the inner rod 19 and within the housing portion 15 is a staple actuating rod 21. The rod 21 is provided at its inner end with a coller 22 carrying a pair of axially opposed screw pins 23 by means of which a pair of toggle pieces 24 are connected with the rod 21. These front toggle pieces 24 are connected at the toggle elbow by means of screw pins 25 with rear toggle pieces 26 and with a toggle connecting link 34 of U shape. The rearmost end of each rear toggle piece 26 is pivotally mounted by means of screws 27 to a flanged plate 28 which is fixed to the body 10 by means of screws 29. The housing 10 is open in the region immediately below the forward toggle pieces 24 and an operating lever 30 is pivotally attached by means of screws 31 to the side walls of the body portion 10 at the forward end of this open region, the side walls of the body portion 10 in this region being straight to form a U-shaped cross-section as shown in Figures 3 to 5. The operating lever 30 which may be of plastics material or pressed metal is of U-shaped cross-section and is connected with the outer end of the connecting link 34 by means of a pin 32. It will be appreciated that movement of the lever 30 towards the body 10 will cause the toggle 24, 26 to drive the staple actuating rod 21 forwardly thereby ejecting staples from the cartridge against the anvil 17. A safety catch 33 is provided, pivotally attached to the operating lever 30 at 33a. This safety catch 33 may be engaged with a catch receiving formation 35 provided on the lower wall of the body 10 to prevent' inadvertent closure of the operating lever, and prior to a stapling operation is moved in a clockwise direction as viewed in Figure 1 to rest against the level 30. This configuration of the parts of the instrument enables single- handed operation since the juxtaposition of the operating lever 30 and the body 10 enables these to be grasped by one hand and the lever 30 operated by a squeezing action, and the mechanical advantage of the mechanism is sufficient to apply to the staple actuating rod 21 greater force than that which is achieved in the known instrument. While in view of the forces which must be borne, the toggle pieces 24 and 26 and the connecting link 33, together with the adjusting rod 19 should be made of metal, preferably of stainless steel, the housing portions 10 and 15 and the staple actuating rod 21, together with the minor functional parts of the assembly, may be of plastics material and in this way the cost of the instrument may be reduced to such an extent that it can be disposed of after a single use, or relatively OMP few uses. In the embodiment illustrated in Figures 7 to 11, those parts of the instrument corresponding to components already described in relation to the embodiment of Figures 1 to 6 are given corresponding reference numerals and will only be mentioned again where necessary. This instrument is of the type comprising a pair of jaws 36 and 37 in a C configuration, the forward jaw 37 carrying a disposable anvil 38. The rear jaw 36 is longitudinally adjustable relative to the instrument housing 10 for adjustment of the tissue gap between the anvil 38 and a staple cartridge 39 prior to operation of the instrument, and this s achieved by mounting the rear jaw 36 on the ends of a pair of parallel frame members 40 which are fixed within the body portion 10 to a sliding block 41 by means of screws 42. The sliding block 41 is in turn attached to the forward end of a threaded rod 20 which by means of a pin 42 is rotated by the adjusting nut 12, so that rotation of the adjusting nut 12 will produce axial movement of the sliding block 41 and consequent adjustment of the position of the cartridge 39 in relation to the jaws 36 and 37. The housing 10 is provided on each side with a slot 43 to provide clearance for the screws. It will be observed that the operating handle and toggle mechanism are identical with those previously described in connection with the embodiment of Figures 1 to 6. The front toggle piece 24 is connected to the rear end of a staple pusher rod 21 which slides within a tube 44, the rear end of which is fixed within the housing 10 by means of a support block 45 mounted on the inner wall of the housing 10 by means of screw 46. The tube 44 is fixed to the block 45 by- means of circlip 47 and shoulder 48. At the forward end of the tube 44 a vertically enlarged portion 49 is provided, which comprises a pair of vertical walls between which the staple pusher head 50, mounted on the forward end of the staple pusher rod 21, may move towards the cartridge 39, and the latter is mounted on the forward end of this portion 49. It will be noted that the frame members 40 straddle the tube 44 and the toggle mechanism in their passage from the sliding block 41 to the rear jaw 36. The materials from which the instrument of Figures 7 to 11 is constructed are chosen in the same way as described above in relation to the preceding embodiment. It will be appreciated that the construction principles exemplified herein may be applied to any surgical stapling instrument of other kinds, and the present invention should not be regarded as limited by the particularity of the illustrated examples. OMPI

Claims: CLAIMS 1. A surgical stapling instrument comprising opposed jaws respectively adapted for carrying an anvil and a staple cartridge and means for ejecting staples from said cartridge against said anvil, adjustment means extending longitudinally of the instrument and longitudinally movable to vary the separation of said anvil and said cartridge, staple ejection actuating means extending longitudinally of the instrument and longitudinally movable to drive said ejection means, characterised in that said instrument further comprises a housing supporting the rearward portions of said adjustment means and said actuating means and an operating handle pivotally mounted at the forward end of said housing, said handle being connected to said actuating means by a toggle thereby to drive said actuating means in its staple-ejecting direction upon closure of said handle towards said housing. 2. An instrument according to claim 1, wherein said toggle comprises a first and second connected links, the free end of said first l nk being pivotally fixed relative to said housing, the free end of said second link being pivotally fixed to said actuating member, the connected ends of said links being connected to a point on said handle rearwardly of the connection of said handle to said housing. 3. An instrument according to claim 1 wherein said actuating means comprises a hollow rod extending between said cartridge and said housing, said adjustment means comprising a rod extending between said jaws and said housing and passing through said actuating means. 4. An instrument according to claim 1 wherein said means comprises a pair of parallel frame members extending respectively on either side of said actuating means and said toggle. 5. An instrument according to claim 3 further characterised in that the jaw carrying said staple cartridge is mounted at the forward end of a tubular jaw mounting member extending from the forward end of said housing. 6. An instrument according to claim 5 further characterised in that said housing and said jaw mounting member are of plastics material. 7. An instrument according to claim 4 further characterised in that said jaws are mounted at the forward end of said frame members, said body being of plastics material. 8. An instrument according to any preceding claim further characterised in that said housing and said handle are disposed and dimensioned such that staple-ejecting operation of said handle may be effected by one hand grasping both said housing and said handle.

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