Surgical stapler and methods - Patent Review 4796793

We claim:

1. A four-bar linkage for operating the staple driver of a surgical stapler and comprising:

a bell crank operatively connected to said driver and pivoted to said stapler at a first pivot;

two drive links pivoted together by a drive pin;

a first one of said links pivoted to said bell crank, and a second one of said links pivoted to said stapler at a second pivot;

a drive cam means mounted on said stapler for motion with respect to said stapler and for engaging and moving said drive pin to operate said driver;

said drive cam presenting an inclined drive surface to said pin during movement of said drive cam.

2. A four-bar linkage, as in claim 1, wherein said drive cam means consists of a straight cam surface.

3. A four-bar linkage, as in claim 1, wherein said drive cam is mounted on a trigger lever and wherein said trigger lever and said bell crank are pivoted to said stapler at said first pivot.

4. A four-bar linkage, as in claim 1, wherein said drive cam traverses an arc extending between said first pivot and said second pivot.

5. A four-bar linkage, as in claim 1, wherein said stapler further includes a toothed rack operably connected to said driver and one arm of said bell crank comprises a toothed gear means operatively coupled to said rack for driving said rack.

6. A four-bar linkage, as in claim 1, wherein said first one of said links is over twice as long as said second link.

7. A four-bar linkage, as in claim 6, wherein said bell crank has two arms, one pivoted to said first link, and being about twice as long as the other bell crank arm.

8. A drive linkage for operating the driver of a surgical stapler having a handle, said linkage comprising:

a trigger lever pivot;

a trigger lever pivoted to said pivot;

a bell crank pivoted to said pivot and having two crank arms;

a drive cam carried on said trigger lever;

two drive links;

a drive pin pivoting the two drive links together at a respective end of each;

one of said drive links pivoted at another end to said handle and the other drive link pivoted at another end to one arm of said bell crank;

another arm of said bell crank operatively connected to said stapler driver; and

said drive cam being engageable with said drive pin to operate said drive linkage and to drive said driver.

9. A linkage, as in claim 8, wherein one arm of said bell crank comprises a toothed gear.

10. A linkage, as in claim 8, further including a rack mounted on said handle and a rack follower mounted on said bell crank, said follower engaging said rack to prevent reverse operation of said stapler prior to a complete operation cycle.

11. A linkage, as in claim 10, wherein one of said rack and said rack follower is yieldably urged toward engagement with the other.

12. A linkage, as in claim 11, wherein said rack follower is yieldably urged into engagement with said rack during operation of said linkage and is urged behind said rack at the end of said operation for return of said linkage to a starting position.

13. A linkage, as in claim 12, wherein said rack follower has a rack engaging end, said rack engaging end traversing one stepped shape arc of one general radius, upon operation of said linkage, and traversing a second smooth arc of greater radius upon return of said linkage to a starting position.

14. A method of delivering and forming surgical staples into tissues to be stapled, wherein a stapler includes a staple supply means for supplying staples, a driver means for driving staples, and an anvil means for forming staples, said method comprising the steps of:

moving said driver means along a path to engage a staple and pick-off the engaged staple from said staple supply means;

further moving said driver means along said path;

engaging said anvil means and pushing said anvil means, together with said staple, from a position adjacent said staple means along said path to a staple forming station;

moving one of said anvil means and said driver means with respect to each other, thereby forming said staple in said tissue; and

retracting said anvil means and said driver means along said path to a position proximate said staple supply means;

wherein said anvil means and driver means retracting step includes the further step of positively locking said anvil means and said staple proximate said staple forming station during an initial portion of said driver means retraction.

15. Drive apparatus for a surgical stapler having a driver for transporting staples from a supply to a forming station and for forming staples about an anvil and in tissue at the forming station, said drive apparatus comprising:

a pivotable lever;

a trigger lever pivot abou which said trigger lever is pivotable;

a drive cam carried by the trigger lever and spaced from said pivot; and

a four-bar linkage means operably connected to drive said driver upon rotation of said trigger lever about said trigger lever pivot, said four-bar linkage means comprising:

a two arm bell crank rotatably mounted about said trigger lever pivot, one of said crank arms being operably connected to said driver and the other said crank arm having a pivot on a distal end thereof;

a first link pivoted at one end to said other crank arm and carrying a drive pin at another end thereof; and

a second link pivoted at one end to said drive pin and at another end to a linkage pivot spaced from, and stationary with respect to, said trigger lever pivot;

said drive pin pivoting said first and second links together being operably engaged by said drive cam for extending said linkage and driving said driver.

16. Drive apparatus as in claim 15, further including spring means for returning said trigger lever to a start position.

17. A surgical stapler apparatus for closing staples in tissue, said apparatus comprising:

a head section;

a longitudinal channel in said head section, said longitudinal channel including a staple driving channel at a forward end thereof;

a staple driver slidably disposed in said longitudinal channel and having a staple driving end in said staple driving channel;

an anvil means slidably disposed in said longitudinal channel adjacent said staple driver, said anvil means including an anvil abutment disposed transversely in said staple driving channel near the staple driving end of said driver;

means for sliding the driver forwardly in said channel to engage and hold a staple between itself and said anvil abutment, and for transporting an engaged staple and said anvil abutment forwardly to a staple closing position; and

stop means for stopping said anvil means in said staple closing position;

said means for sliding the driver forwardly being operable to move said staple driving end of said driver forwardly with respect to said stopped anvil means in said staple closing position for closing a staple about said anvil means;

wherein said anvil stop means is disposed within said longitudinal channel.

18. In a surgical stapler, apparatus for picking a staple from a staple supply, transporting the staple to a forming station, forming the staple, ejecting the staple, and returning to recycle, the apparatus comprising:

an anvil means having an anvil abutment and a staple keeper, the keeper having a forward end defining, with said abutment, a staple receiving pocket, and the keeper further including a staple control surface;

a driver means for engaging a staple at a staple supply, picking off a single staple from said supply and pushing the staple against said anvil abutment and along a staple channel;

said driver means and said anvil means moving together in a longitudinal direction from said staple supply to a forming station;

means for stopping said anvil means at the forming station such that continued forward motion of said driver means forms and closes a staple about said anvil abutment;

means for positively locking said anvil means at the forming station;

means for retracting said driver means from said forming station while said anvil means remains at said forming station, to permit staple ejection, said staple keeper engaging and holding said formed staple against retraction;

means for unlocking said positive anvil locking means after initial driver means retraction; and

means for retracting said anvil means, after staple ejection and said unlocking, in the same direction as said driver means is retracted;

said driver means, upon retraction, passing said staple supply and said staple control surface of said staple keeper engaging and preventing movement of a staple into said channel until said staple receiving pocket is disposed in operative staple-receiving disposition with respect to said supply.

19. Surgical stapler apparatus having a supply of a plurality of staples feeding into a staple pick-up station and having a staple forming station spaced from said staple pick-up station, and including:

a movable driver;

a movable anvil;

means for moving said driver against a staple at said pick-up station, urging said staple against said anvil at said pick-up station, and transporting said driver, staple and anvil together from said pick-up station to said staple forming station while holding said staple between said driver and said anvil;

means for stopping said anvil at said staple forming station while said driver is moved with respect to said stopped anvil in order to form said staple about said anvil; and

means for positively locking said anvil at said staple forming station and holding said anvil against retraction toward said pick-up station until said driver has retracted toward said pick-up station a predetermined distance.

20. Surgical stapler apparatus, as in claim 19, wherein said anvil further includes staple keeper means for holding a formed staple against retraction during initial retraction of said driver through said predetermined distance.

21. Surgical stapler apparatus, as in claim 19, further including unlatch means operatively associated with said driver for releasing said locking means after said driver has been retracted through said predetermined distance in a direction away from said forming station.

22. Surgical stapler apparatus as in claim 21, wherein said driver and anvil comprise flat plates slidably disposed adjacent one another, said driver having an aperture therein and said anvil having a latching tab extending from said anvil through said aperture for engagement by said locking means.

23. Surgical stapler apparatus as in claim 22, wherein said locking means includes a spring biased abutment extendible toward said driver aperture when it registers therewith to engage said latching tab, and said unlatch means comprising release arms mounted on said driver proximate said driver aperture and moving in a path interfering with said locking means when said locking means is extended to engage said latching tab.

24. Surgical stapler apparatus, as in claim 21, wherein said driver and anvil comprise flat plates slidably disposed adjacent one another, said driver having an aperture therein and said anvil having a spring tab extending therethrough and further including spring means connected to said spring tab for urging said anvil in a direction from said forming station toward said pick-up station.

25. Surgical stapler apparatus, as in claim 24, wherein said driver aperture is defined in part by a leading edge, said edge engaging and urging said spring tab and said anvil from said forming station toward said pick-up station after said locking means has been released.

26. Surgical stapler apparatus, as in claim 19, further including spring means for engaging and urging a formed staple away from said anvil when said driver is retracted toward said pick-up station.

27. A surgical stapler apparatus as in claim 19, further including a handle section including manually operable means for operating said stapler and a head section including said staple driver, staple anvil and staple supply, and

coupling means including coupling elements on each of said handle section and said head section, said coupling means operably connecting said handle section to said head section and said manually operable means to one of said anvil and said driver in order to permit separate manufacture of said handle section and said head section and subsequent connection of said sections to form said surgical stapler.

28. A surgical stapler, as in claim 27, wherein said coupling means rotatably couples said head section to said handle section so that said head section is rotatable in at least one plane with respect to said handle section.

Description Submit all comments and votes

This invention relates to staplers and more particularly to surgical staplers for stapling skig or other tissues.

This application discloses and claims subject matter which is disclosed, but not claimed, in a related copending application entitled, "SURGICAL STAPLER DRIVE APPARATUS", filed on even herewith.

In conventional surgical staplers, a staple is driven onto a stationary anvil, disposed at a staple closing or forming station, by a moving driver or former. By virtue of this movement, staple legs are forced into a closed position in which the staple legs engage and secure skin or tissue together. The staple is then released from the stapler and the former returned for another stroke.

In a known alternative system, the anvil is not stationary. Instead, it moves transversely of the moving driver or former into the staple path, as the staple approaches it. After forming, the anvil is retracted in a similar transverse direction to permit staple ejection.

Such conventional surgical staplers typically include a handle and a trigger or lever which can be squeezed to operate the former or driver in a linear path for picking up a staple, moving it to the closing station and forming it about the anvil noted above.

These known surgical staplers are useful, but are attended by a number of structural and functional disadvantages and characteristics which detract from their ease of use and their ease of manufacture.

By way of example, and without limitation, one of the concerns these prior surgical staplers raise is that of the force required to operate the stapler through all of its operating stages. For purposes of discussion, these operating stages generally include a pick-up stage where a staple is picked off a staple supply, a transport stage during which a staple is moved to a staple forming or closing station, a forming stage in which the staple engages an anvil and is closed, and staple ejection and former retraction stages in which the staple is ejected and the former retracted.

Generally, the former or driver is used to pick off the staple from the supply, transport it, and form it. Thereafter, the driver is returned for another cycle. It has thus been required to exert a force on the former or driver to move it through these stages. This driver force is usually generated by applying a manual force to the aforementioned handle and moving its components to cause driver motion through a mechanical connection.

Since surgical staplers are desirably small in structure, as they must be in order to fit into a surgeon's hands for manipulation, the range of movement of the trigger or squeeze handle is practically limited to a small stroke or arc. All the necessary operating forces thus must be applied through a limited stroke movement, and this presents significant structural and operation difficulties.

For example, applicant has observed that the required former or driver operating forces are usually the highest when the staple is being formed, and the staple material is being bent. On the other hand, driver or former forces are relatively low during staple pick-off and staple transport from the supply to the closing station. Moreover, applicant has observed that the distance traveled by the driver during staple forming can be very small as compared to the longer staple transport stroke from the supply pick off to the forming station.

As a result of these relationships, it is not unusual for a surgical stapler to have an operating trigger or handle which must be squeezed with widely varying forces to move it through a complete cycle. Such forces may vary, for example, between fractions of a pound up to 11 poundsor more.

Large force variations are undesirable for several reasons. The manual application of such high forces has the capacity to reduce the precision and steadiness of the staple implanting procedure. At the very point where the staple is engaged with the skin, where maximum preciseness and delicacy are desirable, the surgeon must squeeze the handle much harder, making the process more difficult and perhaps reducing his steadiness with resulting impreciseness.

The constraints of a hand manipulated surgical stapler thus detract from ease of opertion and preciseness.

Accordingly, it has been one objective of this invention to provide an improved hand manipulated surgical stapler with reduced force input requirements, and reduced input force variatios throughout an operating cycle.

A further difficulty with present known surgical staplers is that of staple control, from a point where the staple is picked from a staple supply to a point where the staple is released. In the known staplers discussed above, the staple is free to move forwardly of the driver and toward the stationary or transversely moving anvil unless restrained by additional structural staple retaining or guiding elements. A staple capable of freely moving within a staple path between a pick-off point and a forming station has the capacity to jam or bind the stapler, or even to fall out of the stapler before it is properly formed and implanted. A loose staple in an open incision environment is a condition to be avoided. Loose staples can be difficult to find and retrieve from an open incision.

Accordingly, it has been a further objective of the invention to provide an improved surgical stapler having improved apparatus for picking off a staple from a supply and transporting it to a forming station while positively holding and controlling the staple throughout its movement and until intentionally ejected.

While it is highly desirable to positively control the staple, it is also highly desirable to be able to intentionally eject the staple from the stapler at a particular point in the operative cycle once the staple has been properly implanted or set in skin or tissue. When a staple is formed, it is usually pressed or bent between an anvil and a former or driver and resides there, held frictionally between these two elements. If a staple is not positively ejected from the forming position, it may follow the stapler components, as they are retracted for another cycle, pulling skin or tissue back into the stapler.

Accordingly, it has been a further objective of the invention to provide an improved surgical stapler with apparatus for preventing skin or tissue ingestion into the stapler after a staple has been properly implanted.

In the operation of a surgical stapler, it is desirable to insure that the stapler is operated through a full cycle and that it does not return to a preceding staple or stage during the same cycle. An instrument operating in this manner also allows a surgeon to partially form a staple so that he may more precisely position the staple at the wound site without feature of a staple retraction into the stapler and consequent tissue damage. If the transport or forming stage could be reversed, movement of the transported or partially formed staple back to the pick off point may disrupt the staple supply, or cause binding or jamming.

Accordingly, it has been a further objective of the invention to provide an improved surgical stapler and apparatus therein for insuring a complete cycle once a cycle has begun.

In using a surgical stapler, it is highly desirable that the instrument be an maneuverable as possible. Better maneuverability permits more precise handling and staple implacement.

The size of a surgical stapler is also an important factor in manueverabiity as well as in access to the staple implantation site. Reducing the bulk of the stapler, particularly at the forward end near the staple forming station, is particularly desirable in order to increase visibility of the stapling process. Certain known surgical staplers are somewhat bulky at their forward or operative end and thus reduce visibility.

Accordingly, it has been a still further objective of the invention to provide an improved surgical stapler with a thin structural profile to increase visibility.

In the manufacture of surgical staplers, and particularly with regard to disposable surgical staplers, a plurality of body or shell pieces and a plurality of internal parts are assembled together to form an integral stapler, complete with handle, staple head, and a staple supply device which may be an integral or separable staple holding cartridge. The entire stapler, including these components, is generally tested as a whole. If one component is defective, the entire stapler must be rejected for reworking or disposal.

Moreover, where it is desirable to supply staplers in different staple sizes, or in varying staple counts, it is necessary to manufacture an entire stapler for one size or count, and another entire stapler for another size or count. An entire stapler for each size or count must thus be made or inventoried. Removable staple cartridges of varying staple count may slightly alleviate this situation; however, large numbers of the entire handle and head assemblies must still be stocked for each count variation offered.

Accordingly, it has been a still further objective of this invention to provide an improved surgical stapler in modular form for reducing inventory expense and overall stapler manufacturing and rejection costs during manufacture and inspection.

To these ends, a preferred embodiment of the invention comprises a surgical stapler having a handle section, a head section, and an anvil and driver moving in parallel directions within the head section. The anvil and driver move in longitudinal parallel directions in the head for picking off a staple from a staple supply at a pick-up station therein, transporting the staple to forming station, forming the staple and releasing the staple after forming. The driver forces the staple against the spring-biased anvil at the staple pick-up station, pushing the staple and anvil through a transport section to a forming station. At the forming station, the anvil is stopped and the driver is urged forwardly with respect to the then stopped anvil to form the staple. After staple forming and implantation in skin or tissue, the driver is partially retracted. The anvil, meanwhile, is locked against return motion until the driver clears the staple, permitting its positive ejection before the anvil is thereafter retracted with the driver.

Moreover, the anvil is provided with an integral, dual function, staple keeper. This integral keeper defines a pocket for the staple crown between the keeper and anvil and serves to prevent rearward staple motion when the driver is initially retracted. Also, the keeper serves as a means to prevent prematurely feeding a staple from the supply, once the driver clears the supply station upon retraction, and until the anvil is in proper position for receiving the next staple. Inadvertent feeding of multiple staples into the staple transporting channel is thus eliminated.

In this way, the chance that the formed staple will be frictionally pulled rearwardly upon driver retraction is eliminated, and the staple is positively released. The possibility of ingesting skin or tissue into the stapler as a result of staple ejection failure is substantially eliminated and, at the same time, positive control of a staple feeding is attained.

The handle section preferably incorporates a four-bar mechanical linkage. It is driven by a linkage pin connecting two links in the system and captured in a cam slot carried at the end of a swinging trigger lever. The four-bar linkage is connected to the driver through a gear on the linkage and a rack connected to the driver. This trigger cam, combined with the driver linkage, serves to disperse the required stapler operating forces more widely across the trigger lever stroke, tending to reduce the extent of input force variations required over the operational cycle of the stapler, and at the same time reducing the maximum input force required for staple forming.

An anti-backup rack or ratchet is provided in the handle and a flexible follower disposed on the four-bar linkage. The follower engages the ratchet and prevents undesirable backup until an operational cycle is completed.

The parameters of the four-bar linkage and effective cam slot angle are selected such that the angle of one of the links with respect to a reference axis, less the effective cam slot angle, results in a complementary angle which varies throughout the operating cycle, with the complementary angle variation generally leading changes in the trigger force during the forming stage.

The handle is manufactured as a modular component, and the head, with its moving anvil and driver, is manufactured separately. These components are rotatably joined only after initial operative function testing of each, by means of a snap-in rotatable coupling. Thus, the head can be rotated about at least one axis on the handle to improve maneuverability of the stapler in use.

Accordingly, the invention provides many advantages.

Overall operating input forces are substantially reduced by means of the utilization of the four-bar linkage and cam drive. At the same time, the required input forces are dispersed across the trigger lever stroke so that the range or extent of force variation is reduced. This permits a surgeon to apply a more even squeeze as the stapler is operated through its cycle.

Utilization of a moving anvil which cooperates with, and moves in the same direction as, the driver provides for positive staple control from the pick-up station through the forming station. Moreover, the anvil and driver can be made of thin, elongated members substantially reducing the bulk of the head at the forming station and producing a thin, flat profile for more visibility and maneuverability. Also, the forward locking of the anvil, while the driver initially returns, insures the intentional release and ejection of the staple after it has been formed. This reduces any retraction of the formed staple into the stapler and eliminates ingestion of skin or tissue into the stapler, with possible resultant tearing.

The anti-backup rack and follower maintain the status quo of the stapler components at selected positions to insure that a cycle is completed before any prior steps are repeated. This provides for correct stapler operation and reduces binding or jamming.

Rotatably coupling the head section with respect to the handle section greatly enhances maneuverability of the stapler and permits proper staple orientation in skin or tissue in areas where access may otherwise be difficult.

When the stapler according to the invention is manufactured in modular parts, various economics and ease of manufacture are provided. Specifically, the handles and head are individually tested and rejection of one does not cause loss of the manufacturing cost of the other. Moreover, inventories of various heads, each adapted for use with the same handle, can be provided while handle inventories can be controlled as well. This gives more flexibility to inventory and inventory planning. Additionally, use of a separate head and handle provides two independent parts nests for manufacture, greatly simplifying the manufacturing process.

While each of the features which have been and will be described produced their own independent advantages, the combination of features of the invention described herein provides a much improved surgical stapler, highly maneuverable, and easy to use and operate, while offering positive staple control and retention until intentional staple ejection, together with unique manufacturing and inventory advantages.

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