IMPROVED POCKET CONFIGURATION FOR INTERNAL ORGAN STAPLERS

Abstract: A guiding pocket (10) for driving staples is described, in which a first set of parallel sides (12) helps form the opening for the guiding pockets. These parallel sides are connected to tapered sides (14), which are in turn connected to a second pair of parallel sides (16), creating a hexagonal shaped pocket. The resultant pocket configuration possesses self-centering features, which in turn reduces jamming and misformed staples and allows for simpler manufacturing and inspection.

Description: FIELD OF THE INVENTION The present invention relates to surgical staplers. More particularly, the present invention relates to improved pockets used to guide staples as they are driven to the anvil in a surgical stapler. BACKGROUND OF THE INVENTION Presently, in surgical staplers, staples pass through guiding pockets by means of a driver to a forming surface. These pockets are generally long, rectangular channels through which pass the staples in an unformed state. A pocket conforms to the generally rectangular cross-sectional shape of the staple driver. When the staple passes through the pocket by force of the staple driver, it is guided down the pocket channel and onto the anvil of the stapler. It is at the anvil where the staple driver forms the staple. The staple driver remains in the pocket channel, during forming of the staple. The gap between the driver and the anvil is set so that generally most of the gap is filled by the staple. Generally, the presently used pockets have a rectangular shape. That is, there are generally a first pair of parallel sides which are formed along the length of the unformed staple. This first pair of parallel sides is met by a second pair of parallel sides at right angles. This second pair of parallel sides generally corresponds to the width of the staple and staple driver. However, when the staple passes through the generally rectangular-shaped pocket, it may cause the stapler to jam. This happens when the staple has been loaded in the pocket at an angle to the generally parallel sides of the pocket. When placed at this angle, the staple can be forced by the driver until the staple becomes wedged in the staple forming pocket or is misformed on the anvil. The presently shaped staple pockets have other drawbacks, both in method of manufacture and in ease of operation. Because these staple pockets have the potential to be misloaded or to jam, it is generally desired to keep the tolerances between the forming pockets and the staples very close. This minimizes the chances of the staple being loaded and guided in the pocket in any other way except in a properly aligned fashion. However, when this is done, it is difficult to consistently manufacture the staple pockets to such close tolerances. This is very costly and time consuming. In addition, it is much more difficult to inspect the staple pockets to determine whether they have been maintained at the proper tolerances. Of course, if the tolerances are kept close, there is also the possibility that the staple pockets are manufactured to be too small for the staples. Finally, one other disadvantage of the presently formed staple pockets is that they are difficult to load with staples. This is true because the staples that are misloaded tend to become jammed in the pockets, usually during contact with the staple driver. Because it is not plainly determinable whether the staples will jam within the pockets, the pockets frequently will retain some of the staples. US-A-4 589 582 discloses a surgical staple cartridge having forming pockets of elongated transverse, biconvex cross-sectional shape, terminating in ends adapted frictionally to engage the legs of a surgical staple. Again, manufacturing tolerances are low, owing to the requirement for frictional engagement of the staple by the pockets. In addition, the staple should be aligned with the pockets before being driven and formed, and this is achieved by means of a groove on the driver which engages the bridge of the staple. SUMMARY OF THE INVENTION The present invention overcomes these and other difficulties arising in presently formed staple driving pockets by creating and utilizing a self-centering pocket which is able to maintain the staples in proper alignment. This pocket is also easy to measure and manufacture. Essentially, the pocket comprises a pair of parallel sides each connected to a pair of tapered sides. This pair of tapered sides culminates at a second pair of parallel sides, preferably situated at right angles to the first pair of parallel sides. Thus, the improved guiding pocket takes on a generally hexagonal shape. It is this hexagonal shape which allows the staple to center itself inside the pocket. That is, when the staple is loaded into the channel, the staple is encouraged to move toward an aligned position, along the axis of the first pair of parallel sides. A stapler and staple cartridge according to the invention are respectively defined in claims 1 and 5. These and other aspects of the preferred embodiment of the present invention will be better understood from the accompanying detailed description of the drawings as well as the detailed description in which: DETAILED DESCRIPTION OF THE DRAWINGS Figures 1, 2, and 3 are bottom views of typical improved staple pockets; Figures 1a, 2a and 3a are bottom views of prior art embodiments of staple pockets; Figure 4 is an elevation view of the staple guiding pockets of the present invention in relationship to staple drivers; Figure 5 is a sectional view of a preferred embodiment of the staple guiding pocket of the present invention as taken along lines 5-5 of Fig. 4; and Figure 6 is a partial sectional view of the staple guiding pockets of the present invention as used in a surgical stapler. DETAILED DESCRIPTION As seen in Figures 1a-3a, the prior art staple guiding pockets are configured to have generally close tolerances. This is due mostly to the shape of these guiding pockets. Generally these guiding pockets will be formed so that the staple can be loaded inside the guiding pocket in one fashion. If these close tolerances are kept up to specification, then the guiding pockets are able to accurately hold and guide the staples. However, generally the guiding pockets will be formed with a wider tolerance than the size of the staple. When this occurs, it is possible for the staple to be wedged inside the guiding pocket. When this occurs, of course, it delays use of the stapler because the staple must be evacuated from the pocket. The present invention, as seen in Figures 1-3, overcomes this difficulty. The new pocket 10 has a pair of first parallel sides 12. Each of these parallel sides 12 has two ends. These ends are connected to a pair of tapered sides 14. These tapered sides 14 generally extend from beyond first parallel sides 12 for the length of the staple, to a pair of second parallel sides 16. These second parallel sides 16 connect to both pairs of tapered sides 14. As seen in Figures 4-6, these pockets can be used in staple cartridge 30 containing pockets 20. The drivers 40 pass from the staple cartridge 30 so that the staples pass through the pockets 20 onto the anvil 50 of the stapler. The pockets 20 are placed strategically to create the staple forming gap G which will cause the staples to be formed to a certain height in order to close the skin to be stapled. The resultant pocket of the present invention allows the staple to be self-centering. Return to Figures 1-3, should the staple become placed in the pocket 10 along the tapered sides 14 of the pocket 10, as seen in phantom, Figure 1, the staple 10 will necessarily rotate toward the appropriate axes so that it fits into a guiding pocket 10 correctly, as demonstrated in the adjoining pocket of Figure 1. This is due to the geometry of the pocket of the present invention. The staple slides against the sides of the guiding pocket wall so that it becomes properly aligned. This feature of the pocket is a substantial improvement over the presently practiced pocket. With the new shape of the pocket, jamming is reduced, as well as misforming of staples. Stapling can occur more reliably. This also allows for simpler manufacturing and inspection of staple cartridges. Also, the preferred embodiment of the present invention makes measurement of the pocket size much easier. These pockets can accommodate staple wire diameters generally in the range from 203.2 to 279.4 µm (.008 to .011 inches), although these are not critical dimensions. Of course, the length of the first parallel sides and tapered sides may have any dimension required to fit the surgical staple. In this instance, the angle between the first parallel sides and the tapered sides is maintained at about 22.5°. This is the optimal angle to insure the self aligning features of the present invention for a range of different staple wire diameters. The present invention therefore, can be used in all types of internal organ surgical staplers, especially the RL 30V, PLC-50, and any 60 millimeter cartridges made by the assignee of the present invention.

Claims: A stapler having pockets (10;20) through which pass staple drivers (40) adapted to drive unformed staples, each of said pockets (10;20) generally conforming to the shape of one of said unformed staples, said pockets (10;20) permitting said drivers (40) to position said unformed staples on anvils for forming said staples, each one of said pockets (10;20) having first parallel sides (12) generally corresponding to the length of said unformed staples, said first parallel sides (12) being connected by second parallel sides (16) to form said pocket (10;20), said second parallel sides (16) generally conforming to the width of said unformed staples, characterised in that there is a tapered side (14) at each end of each first parallel side (12), each of said tapered sides (14) diagonally approaching one of said second parallel sides (16), the resulting pocket (10;20) having a generally hexagonal shape, wherein staples within said pocket become self-aligning. The stapler of Claim 1, wherein said tapered sides (14) are at angles of about 22.5° relative to the first parallel sides (12). The stapler of Claim 1 or Claim 2, wherein said second parallel sides (16) have a length of about 203.2µm (0,008 inch). The stapler of Claim 1 or Claim 2, wherein said second parallel sides (16) have a length of about 279.4µm (0,011 inch). A staple cartridge (30) having pockets (20;10) for emplacement of staples, said pockets (20;10) having a pair of first parallel sides (12) generally corresponding to the length of said unformed staples, said first parallel sides (12) being connected by second parallel sides (16) to form said pocket (10;20), said second parallel sides (16) generally conforming to the width of said unformed staples, characterised in that there is a tapered side (14) at each end of each first parallel side (12), each of said tapered sides (14) diagonally approaching one of said second parallel sides (16), the resulting pocket (10;20) having a generally hexagonal shape. The pocket of Claim 5, wherein said tapered sides (14) are angularly displaced from said first pair of parallel sides (12) at an angle of about 22.5°. The pocket of Claim 5 or Claim 6, wherein said second pair of parallel sides (16) have a length in the range of about 203.2µm to about 279.4µm (about 0.008 to about 0,011 inches).

Inventors: ROTHFUSS, ROBERT G.
Applicants: ETHICON INC.
Application year: 1989
Main classification: A61B17
IPC codes: A61B17