Cartridge retainer for a curved cutter stapler

A surgical instrument is adapted for stapling tissue in a highly controlled manner. The surgical instrument includes a frame having a proximal end and a distal end, with a handle positioned at the proximal end and an end effector positioned at the distal end. The end effector is shaped and dimensioned for selectively receiving a cartridge module containing a plurality of surgical fasteners. A firing mechanism is associated with the end effector and the cartridge module for selective actuation of the surgical fasteners. The cartridge module includes a cartridge housing in which the surgical fasteners are housed and an anvil shaped and dimensioned for engagement with the surgical fasteners to facilitate stapling. The cartridge housing and anvil are relatively movable between a first spaced apart position and a second position in close approximation with one another. A retainer is removeably positioned between the anvil and the cartridge housing to prevent undesired movement of the cartridge housing toward the anvil.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a surgical stapling and cutting instrument adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the invention relates to a retainer for a cartridge module used in conjunction with a surgical stapling and cutting instrument.

2. Description of the Prior Art

Within the field of surgery, the need to surgically seal tissue and to cut tissue is quite commonplace. Sealing of tissue may be accomplished by numerous sealing devices, for example, surgical staplers. Cutting of tissue may be accomplished by numerous cutting devices, for example, scalpels and surgical scissors. Stapling and cutting of tissue in several steps during the surgical procedure adds time to such procedures. In order to reduce procedural steps and ultimately the time necessary for various surgical procedures, instruments have been developed which simultaneously apply staples and cut desired tissue. As those skilled in the art will certainly appreciate, it is desirable to provide stapling and cutting instruments capable of performing multiple stapling and cutting routines during a single procedure.

Some current surgical instruments provide stapling and cutting mechanisms that operate in the same direction during device actuation, or firing. For instance, staple formation and tissue cutting occur along the same plane on the tissue. These instruments generally utilize an anvil, which holds staple pockets (or staple forming surfaces) and a washer, and a housing assembly, which holds staples and a knife. In these prior instruments, the anvil is generally a permanent element of the instrument and the housing assembly is either a permanent element (single-fire device) or a reloadable element (multiple-fire device). Tissue is captured between the anvil and the housing assembly of the device. Actuation of the instrument moves the staples from the housing assembly toward the anvil. The staples puncture the captured tissue and then contact staple pockets on the anvil, which form the staples into desired shapes to seal the tissue. In conjunction with the staple formation, actuation of the instrument also moves the knife from the housing assembly toward the anvil. The knife pushes the tissue toward the anvil and, upon contact with the knife and the washer on the anvil, cutting of the tissue is facilitated. Cutting in this manner is similar to cutting on a cutting board.

The washer is generally made of a resilient material and is a permanent element of the anvil. The knife is either a permanent element that actuates within the housing assembly or a reloadable element with the housing assembly. For single-fire instruments, the washer and knife are discarded with the complete instrument after firing. Single-fire instruments present higher associated costs since a new instrument is needed for subsequent firings. For multiple-firing instruments, the housing assembly is discarded and a new housing assembly is reloaded while the anvil with accompanying washer is reused for subsequent firings.

These prior surgical stapling and cutting instruments often include a retainer adapted for preventing movement of the staples or knifes. For example, many of these retainers snap onto the outside of the cartridge housing or slip into the knife slot of the cartridge housing. Unfortunately, these prior art retainers are easily dislodged allowing components, in particular the staples, to move out of position.

As such, it is apparent currently cartridge modules includes a variety of shortcomings. As a result, it is desirable to provide a cartridge module for surgical stapling and cutting instruments adapted to include an anvil coupled to a cartridge housing within which are located various moving components such as a knife and staples. The present invention provides a cartridge module for a surgical stapling and cutting instrument which includes a retainer to prevent movement of the modules components prior to use.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a surgical instrument adapted for stapling tissue in a highly controlled manner. The surgical instrument includes a frame having a proximal end and a distal end, with a handle positioned at the proximal end and an end effector positioned at the distal end. The end effector is shaped and dimensioned for selectively receiving a cartridge module containing a plurality of surgical fasteners. A firing mechanism is associated with the end effector and the cartridge module for selective actuation of the surgical fasteners. The cartridge module includes a cartridge housing in which the surgical fasteners are housed and an anvil shaped and dimensioned for engagement with the surgical fasteners to facilitate stapling. The cartridge housing and anvil are relatively movable between a first spaced apart position and a second position in close approximation with one another. A retainer is removeably positioned between the anvil and the cartridge housing to prevent undesired movement of the cartridge housing toward the anvil.

It is also an object of the present invention to provide a surgical instrument wherein the retainer includes a disengagement structure.

It is another object of the present invention to provide a surgical instrument wherein the disengagement structure includes a tab which contacts the end effector for release of the retainer upon insertion of the cartridge module within the end effector.

It is a further object of the present invention to provide a surgical instrument wherein the tab is spring biased

It is also another object of the present invention to provide a surgical instrument wherein the retainer includes containment slots shaped and dimensioned for extending partially around a guide pin of the end effector and securing the retainer to the guide pin.

It is still another object of the present invention to provide a surgical instrument wherein at least one of the containment slots is pivotally mounted on the retainer and the retainer includes a tab which contacts the end effector upon insertion of the cartridge module within the end effector causing rotation of the at least one containment slot and selective release of the retainer from the cartridge module.

It is yet another object of the present invention to provide a surgical instrument wherein the retainer includes a first containment slot and a second containment slot, the first and second containment slots being opposed for securing the retainer to the guide pin.

It is also an object of the present invention to provide a surgical instrument wherein the second containment slot is spring biased for selective release of the retainer.

It is still a further object of the present invention to provide a surgical instrument including a frame having a proximal end and a distal end, with a handle positioned at the proximal end and an end effector positioned at the distal end. The end effector is shaped and dimensioned for selectively receiving a cartridge module containing a plurality of surgical fasteners. A firing mechanism is associated with the end effector and the cartridge module for selective actuation of the surgical fasteners. The cartridge module includes a cartridge housing in which the surgical fasteners are housed. A retainer is removeably positioned upon the cartridge module for preventing staples from falling out of the cartridge housing, wherein the retainer includes a locking mechanism having a first release force when the cartridge module is separate from the end effector and a second release force when the cartridge module is fully positioned within the end effector, wherein the first and second release forces are different.

It is also an object of the present invention to provide a cartridge module containing a plurality of surgical fasteners for a surgical instrument adapted for stapling tissue in a highly controlled manner, wherein the surgical instrument includes an end effector shaped and dimensioned for selectively receiving the cartridge module. The cartridge module includes a cartridge housing in which the surgical fasteners are housed and a retainer removeably positioned upon the cartridge module for preventing staples from falling out of the cartridge housing. The retainer includes a locking mechanism having a first release force when the cartridge module is separate from the end effector and a second release force when the cartridge module is fully positioned within the end effector, wherein the first and second release forces are different.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the various figures, the present invention is directed to a surgical instrument20adapted for stapling and cutting tissue in a highly controlled manner. The instrument20generally includes a frame having a proximal end and a distal end, with a handle21positioned at the proximal end and an end effector80positioned at the distal end. The end effector80includes a C-shaped supporting structure81shaped and dimensioned for selectively receiving a cartridge module120containing a plurality of surgical fasteners and a knife. The surgical instrument further includes a firing mechanism associated with the end effector80and the cartridge module120for selective actuation of the surgical fasteners and knife126. Finally, the cartridge module120includes a cartridge housing121in which the surgical fasteners and knife are housed and an anvil122shaped and dimensioned for engagement with the surgical fasteners and knife to facilitate cutting and stapling. The cartridge housing121and anvil122are relatively movable between a first spaced apart position and a second position in close approximation with one another. A retainer160selectively positioned between the anvil122and the cartridge housing121is further provided to prevent undesired movement of the cartridge housing121toward the anvil122. The retainer160includes a disengagement structure, which has a tab165that contacts the end effector80for release of the retainer160upon insertion of the cartridge module120within the end effector80.

Referring toFIG. 1in combination withFIGS. 2 to 5, there is shown a surgical stapling and cutting instrument, in particular, a linear surgical stapler20which is designed to staple and cut tissue. The linear surgical stapler20has a handle21at a first proximal end and an end effector80at an opposite distal end. The end effector80is curved in accordance with a preferred embodiment of the present invention. Right and left hand structural plates (often called “handle plates”)34,35, respectively, connect the handle21to the end effector80of the instrument (the left hand handle plate is not shown inFIG. 1). The handle21has a right hand shroud22coupled to a left hand shroud (the left hand shroud is not shown inFIG. 1). The handle21also has a body portion23to grip and maneuver the linear surgical stapler20(seeFIGS. 2 to 5).

The end effector80is a surgical fastening assembly that includes a cartridge module120(seeFIGS. 6 to 9) and a C-shaped supporting structure81. The term C-shaped is used throughout the specification to describe the concave nature of the supporting structure81and the cartridge module120. The C-shaped construction facilitates enhanced functionality and the use of the term C-shaped in the present specification should be construed to include a variety of concave shapes which would similarly enhance the functionality of surgical stapling and cutting instruments. The distal end30of a closure member28is disposed to receive the cartridge module120. The end effector80also includes a safety lockout mechanism180(best seen inFIG. 31) for preventing the firing of a previously fired cartridge module120. The cartridge module120contains a cartridge housing121coupled to an anvil122. The cartridge module120also includes a retaining pin125, a knife126, a removable retainer160, a tissue contacting surface127which displays a plurality of staple-containing slots128in staggered formation in one or more rows (that is, staple lines) on either side of the knife126. Staples (not shown) are fired from the cartridge housing121against staple-forming surface129of the anvil122that faces the tissue-contacting surface127of the cartridge housing121.

As will become apparent based upon the following disclosure, the present linear surgical stapler20is designed as a multiple firing device with a replaceable cartridge module120. However, it should be understood that many of the underlying concepts of the present invention may be equally applied in single firing devices without departing from the spirit of the present invention.

The supporting structure81of the end effector80is respectively attached to the right and left handle plates34,35, by a shoulder rivet82and posts83which extend from the supporting structure81into receiving holes in the handle plates34,35. In accordance with a preferred embodiment of the present invention, the supporting structure81is formed via a single piece construction. More specifically, the supporting structure81is formed by extrusion, for example, of aluminum, with subsequent machining to create the supporting structure81disclosed in accordance with the present invention. By constructing the supporting structure81in this manner, multiple parts are not required and the associated cost of manufacture and assembly is substantially reduced. In addition, it is believed the unitary structure of the supporting structure81enhances the overall stability of the present linear surgical stapler20. In addition, the unitary extruded structure of the supporting structure81provides for a reduction in weight, easier sterilization since cobalt irradiation will effectively penetrate the extruded aluminum and less trauma to tissue based upon the smooth outer surface achieved via extrusion.

The handle21of the linear surgical stapler20includes a hand grip24which the surgeon grasps with the palm of his hand (seeFIGS. 2 to 5). The hand grip24is composed of a right hand shroud handle25(seeFIG. 1) and a left hand shroud handle (the left hand shroud handle is not shown inFIG. 1). Pivotally extending from the underside of the handle21are a closure trigger26and a firing trigger27. The linear surgical stapler20illustrated inFIG. 1is shown with the closure and firing triggers26,27in their unactuated positions and with a cartridge module120inserted and the retainer160removed. Consequently, the cartridge housing121is spaced from the anvil122for the placement of tissue between the cartridge housing121and the anvil122.

The handle21of the linear surgical stapler20contains a tissue retaining pin actuation mechanism100. The tissue retaining pin actuation mechanism100includes a saddle shaped slide101positioned on the top surface of the handle21. Manual movement of the slide101results in distal movement of the push rod102. The push rod102is coupled to the retaining pin125of the cartridge module120. The distal movement or proximal retraction of the push rod102results in corresponding movement of the retaining pin125. The retaining pin actuation mechanism100is also releasably coupled to the closure trigger26within the handle21such that actuation of the closure trigger26will result in automatic distal movement of the retaining pin125if it has not already been manually moved to its most proximal position.

Referring briefly toFIGS. 2 to 5, there is illustrated what happens when the cartridge module120is loaded and the closure and firing triggers26,27are sequentially squeezed toward the hand grip24to actuate the end effector80of the linear surgical stapler20. The linear surgical stapler20is loaded with the cartridge module120, as shown inFIG. 2, and the retainer160is removed. The linear surgical stapler20is now ready to receive tissue as shown inFIG. 1.

When the closure trigger26is partially squeezed to rest in its first detent position shown inFIG. 3, the cartridge housing121moves from its fully opened position to an intermediate position between the open and closed positions as discussed below in greater detail. Simultaneously, the tissue retaining pin actuation mechanism100moves the retaining pin125forward from the cartridge housing121through an opening in the anvil122. In this position, tissue which has been placed between the cartridge housing121and the anvil122can be properly positioned, and the retention of the tissue between the cartridge housing121and the anvil122is assured. Therefore, when the closure trigger26has been actuated to its intermediate position, the cartridge housing121and anvil122are correspondingly positioned in their tissue retaining positions.

When the closure trigger26is fully squeezed so that it is adjacent the forward end of the hand grip24, as illustrated inFIG. 4, the tissue contacting surface127of the cartridge housing121and the staple-forming surface129of the anvil122are adjacent to each other, and the properly positioned and retained tissue is consequently fully clamped. Additionally, the firing trigger27has rotated counterclockwise toward the handgrip24to enable the surgeon to grasp the firing trigger27for the firing of staples. Accordingly, the firing trigger27is now in position for the surgeon to squeeze it to staple and cut the tissue. When the firing trigger27has been fully squeezed to fire the staples, as shown inFIG. 5, the firing trigger27rests in near proximity to the closure trigger26.

Referring now toFIGS. 6 to 9, a more detailed description of the cartridge module120is presented. The present cartridge module120provides a cutting and sealing mechanism for utilization within the linear surgical stapler20wherein the stapling and cutting functions operate in the same direction during device actuation. Although the present cartridge module120is particularly adapted for use in conjunction with linear surgical stapling devices, the concepts of the present cartridge module120may be applied to other surgical devices without departing from the spirit of the present invention. In particular, the present cartridge module120provides that the knife126be utilized in conjunction with a corresponding washer123during the cutting process. The present cartridge module120ensures that multiple firings of the linear surgical stapler20will not compromising cutting performance. This is accomplished by incorporating the anvil122, in particular, the cutting washing123, with the cartridge module120. By combining the washer123with the cartridge module120, a new washer123is provided each time the cartridge module120is replaced, resulting in improved cutting performance.

Enhanced performance is further provided by positioning the anvil122and the cartridge housing121parallel such that they move relative to each other with the facing surfaces of the anvil122and the cartridge housing121maintained in a parallel orientation. This provides for an even distribution of pressure across the tissue, preventing squeezing of the tissue in a manner which might bunch the tissue and force portions of the tissue out of the desired spaced defined between the anvil122and the cartridge housing121.

More specifically, the cartridge module120includes a cartridge housing121that contains a plurality of staples (not shown) positioned in staple-containing slots128. Immediately behind the staples is disposed a driver131which is disposed to push the staples out of the staple slots128. A knife holder130is disposed immediately proximal of the driver131in the cartridge housing121. The knife holder130contains a slot172and ledge173for interaction with a knife retractor hook45(seeFIG. 37) the function of which will be discussed below in greater. The knife holder130is attached to a knife126that extends distally from the knife holder130through a slot200in the driver131and through a slot199in the cartridge housing121. Although the knife is disclosed as being within the housing in accordance with a preferred embodiment of the present invention, other configurations may be employed without departing from the spirit of the present invention; for example, it is contemplated that the cartridge module could be constructed without a knife if specific applications so dictate.

The knife holder130has a detent post138that extends through the slot137in the cartridge housing121. The knife holder detent post138is disposed to contact detent protrusion139of the cartridge slot137during the longitudinal travel of the knife126and the knife holder130. Similarly, the driver131has a detent post140that is disposed to contact proximal and distal detent protrusions141,142, respectively, of the cartridge slot137.

The knife126and slots199,200are positioned such that there is at least one row of staples on either side of the knife126. In accordance with a preferred embodiment of the present invention, two rows of staple slots128(and two rows of staples) are provided on each side of the slot199of the cartridge housing121.

The cartridge housing121contains two generally circular openings143,144at either end of the knife slot199. The general circular opening143at the base of the cartridge housing121is shaped and dimensioned for the passage of a guide pin124through the cartridge housing121. The generally circular hole144at the top of the cartridge housing121is shaped and dimensioned for the passage of a retaining pin125through the cartridge housing121. The staple slots128are arranged such that the staples laterally extend past the generally circular holes143,144.

In accordance with a preferred embodiment of the present invention, the anvil122includes a plastic washer123and a metallic staple-forming surface129. The anvil122is disposed to maintain staple-forming surface129in a matching configuration with the staples. The retaining pin125is connected to a coupler133by a circumferential slot135in the retaining pin125and a groove134in the coupler133(best seen inFIG. 14). The coupler133is disposed within an arm145of the cartridge housing121and is held into the arm145by an end cap146.

The guide pin124and retaining pin125include respective slots147a,147b(best seen inFIGS. 8,9,36,39and40) into which the ends126a,126bof the knife126are disposed. The proximal end148of the guide pin124is connected to the proximal end149of the anvil122. The distal end150of the guide pin124extends from the cartridge housing121and extends through a slot151of the anvil122. A cutting washer123slips onto the anvil122by means of a groove152on the anvil122that fits under a tongue153on the washer123. The opposite end154of the cutting washer123slips under the anvil arm155and is pinned to the anvil arm155by a pin156. In this position, the cutting surface157of the washer123extends up through a slot151of the anvil122. The assembly of the cutting washer123to the anvil122traps the guide pin124into the opening formed by the anvil slot151and the cutting surface157, thereby, operatively connecting the anvil122to the cartridge housing121. The retainer160is attached to the cartridge module120as shown inFIG. 7to hold the components of the cartridge module120in a desired orientation until insertion into the end effector80.

Turning toFIGS. 6 to 12,25to29,41and42, the retainer160will be described in more detail. The retainer160has a groove161that is disposed around a protrusion159of the cartridge housing121. The retainer160contains a resilient inner spring arm162that is disposed for reciprocating movement within the retainer160. The retainer160includes containment slots163which extend partially around the guide pin124. The spring arm162includes containment slots164which extend partially around the guide pin124, but are configured to face in an opposing direction to the containment slots163. The retainer160is positioned onto the cartridge module120such that the containment slots163,164surround the guide pin124and trap the retainer160onto the cartridge module120. The spring arm162includes a disengagement tab165which extends down from the retainer160below the anvil arm155. As such, the retainer160is not easily removed from the cartridge module120until the cartridge module120is properly seated within the end effector80. Upon proper seating of the cartridge module120within the end effector80, the disengagement tab165engages the end effector80for release of the retainer160.

Referring once again toFIG. 1in combination withFIG. 2andFIG. 13, a more detailed description of the components of the linear surgical stapler20is provided. The linear surgical stapler20includes an elongated closure member28, with a generally U shaped cross section, extending from the handle21into the surgical fastening assembly of the end effector80. In accordance with a preferred embodiment of the present invention, the closure member28is a molded plastic member shaped for movement and functionality in accordance with the present invention. By manufacturing the closure member28from plastic, manufacturing costs are reduced and the weight of the linear surgical stapler20is also reduced. In addition, the linear surgical stapler20is easier to sterilize with cobalt irradiation as plastic is easier to penetrate than stainless steel. In accordance with an alternate embodiment, the closure member may be made from extruded aluminum with the final features machined into place. While an extruded aluminum closure member might not be as easy to manufacture as the plastic component, it would still have the same advantages (i.e., elimination of components, easier to assemble, lower weight, easier to sterilize).

The distal portion of the closure member28passes through the walls84of the supporting structure81. The distal end is disposed to receive and retain the cartridge housing121of the cartridge module120. The central portion of the closure member28is positioned between the right and left handle plates34,35, respectively. Right and left hand closure links36,37, respectively, are pivotally attached at the right and left proximal ends of the closure member28by a first integral closure link pin38. At the opposite end of the closure links36,37, the closure links36,37are pivotally attached to a second integral closure link pin39. The second integral closure link pin39connects the closure links36,37to a slotted closure arm link40. The slotted closure arm link40is pivotally mounted to the handle plates34,35of the linear surgical stapler20at a closure trigger pivot pin41. The closure trigger26descends from the slotted closure arm link40for pivotal rotation about the closure trigger pivot pin41toward and away from the handgrip24. A closure spring42housed within the hand grip24of the handle21is secured to the slotted closure arm link40to provide a desired resistance when the surgeon squeezes the closure trigger26toward the handle grip24, and to bias the closure trigger26toward the open position.

Referring toFIGS. 13 and 14, the components of the retaining pin actuation mechanism100will now be described. The handle21contains a saddle shaped slide101mounted on top of the handle21for linear motion. The slide101is connected to a post103that extends outward from a push rod driver104through slots105(seeFIG. 2) in the handle21. The push rod driver104is restrained for longitudinal movement along the long axis of the linear surgical stapler20by slots105. The push rod driver104is connected to the push rod102by a circumferential groove107on the push rod102that snaps into a slot108of the push rod driver104. The distal end of the push rod102contains a circumferential groove109that interconnects with a groove132in the proximal end of the coupler133of the cartridge module120(best seen inFIG. 22). The distal end of the coupler133contains a groove134for interconnecting with a circumferential slot135on the retaining pin125.

The closure member28contains posts29which extend laterally on both sides of the closure member28inside the handle21. These posts29slidably connect to an L-shaped slot110of a yoke111. The yoke111is pivotally mounted to the handle21by a pivot pin112on the yoke111. The yoke111contains cam pins113positioned to push camming surfaces114on the push rod driver104.

Referring toFIG. 13andFIG. 37, the components of the firing transmission assembly will now be described. The firing transmission assembly has an elongated firing bar43extending from the handle21into the surgical fastening assembly of the end effector80. The firing bar43is positioned within the U shaped cross section of the closure member28. The distal end of the firing bar43extends into the cartridge housing121and is positioned just proximally of the knife holder130and driver131. The distal end of the firing bar43is attached to a knife retractor44that has a knife retraction hook45.

The firing bar43has a rectangular receiving slot46in that portion of the firing bar43that is housed within the handle21(seeFIG. 13). The first integral closure link pin38extends through the receiving slot46. The firing bar43also has a proximal end section47. The underside of the proximal end section47of the firing bar43has a sliding surface48. The proximal end section47also has a terminal side engagement surface49extending from the sliding surface48. The firing trigger27is pivotally mounted to the handle plates34,35by a firing trigger pivot pin50spaced from the closure trigger pivot pin41so that each of the pivot pins pivot about mutually independent axes. The firing trigger27includes an arcuate firing trigger link51extending from the firing trigger27at the firing trigger pivot pin50to an apex52which rests on the sliding surface48of the proximal end section47of the firing bar43. Within the handle21, the firing trigger27is attached to first and second firing trigger spring arms53,54, respectively. The firing trigger spring arms53,54support a torsion spring (not shown) on the right half of the firing trigger43. Finally, a firing bar return spring55is secured to the underside of the firing bar43at that portion of the firing bar43within the handle21to bias the firing bar43toward its unactuated position.

When the closure trigger26is squeezed toward the handgrip24, the slotted closure arm link40and the closure links36, move distally within the receiving slot46of the firing bar43. This distal movement causes the closure member28to correspondingly move distally. Likewise, the firing bar43concurrently moves distally with the closure member28because the first integral closure link pin38, to which the closure links36,37are attached, extends through the receiving slot46in the firing bar43.

The mechanism which defines an intermediate closure detent position and the release of the closure trigger26from an actuated position to its original unactuated position will now be described in connection withFIG. 1in combination withFIGS. 13–20. The top side of the slotted closure arm link40has a clamp sliding surface56that displays an intermediate detent57and a closure detent58. A release pall59slides on the clamp sliding surface56and may engage the intermediate and closure detents57,58. The release pall59has a laterally extending pall lug60(best seen inFIG. 1) at its distal end. The release pall59is located within the handle21, and it is integrally attached to a release button61situated exteriorly of the handle21. The release button61has a thumb rest62, and the release button61is pivotally attached to the handle21by a release trunnion63. The release button61is biased outwardly from the handle21and, therefore, the release pall59is biased downwardly toward the clamp sliding surface56by a release spring64which is mounted to the handle21by a spring retention pin65and mounted to the release button61by a button spring post66. The slotted closure arm link40has an arcuate recess67located between the intermediate and closure detents57,58. Sitting within this arcuate recess67for rotational movement are a left hand toggle68integrally connected to a right hand toggle (the right hand toggle is not shown). Each toggle68has a toggle arm69that is engageable with the pall lug60. The pall lug60has a concave proximal surface70to provide clearance between the toggle arm69and the pall lug60.

Referring toFIG. 31(cut away view into cartridge and supporting structure), the components of the fired device lockout mechanism180will now be described. The lockout mechanism180contains a lockout lever181that is pivotally mounted to the distal end30of the closure member28by a pin182. The lockout lever181is spring biased down toward the base of supporting structure81by a spring (not shown). The lockout lever181contains a proximal and distal end184,185, respectively. The proximal end184has a cam surface186and locking groove187. The supporting structure81of the end effector80contains a ledge85that is disposed to interact with locking groove187when the lockout mechanism180is engaged. The supporting structure81contains a base surface86between walls84. The base surface86is disposed to interact with cam surface186when the lockout lever181is not engaged.

The operation of loading the cartridge module120, the closure mechanism, the retaining pin mechanism, the firing transmission assembly, the intermediate and closure detents57,58, the release mechanism, and the lockout mechanism180will now be described. Referring toFIGS. 7 to 12andFIGS. 21 to 28the loading of the cartridge module120into the tissue end effector80is described. The cartridge module120is shaped and dimensioned for selective insertion and removal from the tissue end effector80of the linear surgical stapler20.

Prior to insertion of the cartridge module120into the end effector80of the linear surgical stapler20, as seen inFIG. 7, the retainer160can not easily be removed from the cartridge module120as the groove161is disposed around the protrusion159at the top end of the retainer160preventing disconnection. Further, the containment slots163,164of the retainer are disposed around the guide pin124at the bottom of the retainer160preventing disconnection as shown inFIG. 25. The attached retainer160provides support to the structure of the cartridge module120and an extended surface area for gripping, both features making loading easier. The retainer160also prevents staples from dislodging from the cartridge housing121during casual handling and prevents the knife126from accidental exposure during casual handling.

Knife126movement and staple movement are further resisted prior to loading and during loading by a series of detents. Referring toFIG. 9, detent post138on the knife holder130is prevented from proximal and distal movement by the detent protrusion139on the cartridge housing slot137. The driver131is prevented from distal movement due to casual handling and during loading of the cartridge module120into the linear surgical stapler20by the interaction of the detent post140and the detent protrusion141on the cartridge housing slot137.

The cartridge module120is loaded into the tissue effector80such that the cartridge housing121slips into the distal end30of the closure member28as seen inFIGS. 21 to 24. Walls31aand31bon the closure member28slip into slots170a,170bof the cartridge housing121during loading. Simultaneously, tabs174(SeeFIG. 8) slip into groove88of the C-shaped supporting structure81. Loading of the cartridge module120is completed when the detents171snap onto the detent groove32of the closure member distal end30, as shown inFIGS. 21 to 24.

In the position shown inFIG. 24, the cartridge module120is fully loaded and the proximal groove132of the coupler133has engaged the distal circumferential groove109of the push rod102such that the retaining pin125in the cartridge module120has been connected to the retaining pin advancement mechanism100. The slot172of knife holder131engages the knife retraction hook45during loading such that the hook45has engaged the retraction ledge173on the knife holder130at the completion of the cartridge module120loading.

At the completion of the cartridge module120loading a post188positioned on driver131contacts the distal end185of the lockout lever181(seeFIG. 31). This contact pivots the lockout lever181about the lockout lever pin182to a position such that the camming surface186is horizontally aligned with the base surface86of the U shaped supporting structure81.

The retainer160can now be removed from the end effector80. Specifically, completion of loading the cartridge module120causes the disengagement tab165to contact the supporting structure81(SeeFIG. 23), resulting in an upward movement of the spring arm162when the cartridge module120is fully loaded as inFIG. 24. This upward movement displaces containment slots164upward such that the guide pin124is no longer contained (seeFIGS. 25 and 26). Referring now toFIGS. 27 to 29, a removal force applied to the thumb pad166results in the retainer160pivoting outward about protrusion159until the groove161is able to slip off protrusion159. Removal of the retainer160allows for the loaded linear surgical stapler20to be utilized.

InFIG. 15, the closure trigger26has been partially squeezed from its open, unactuated position illustrated inFIGS. 1 and 13. When the closure trigger26is partially squeezed, it pivots about the closure trigger pivot pin41in a counterclockwise direction toward the handgrip24. As it pivots, the slotted closure arm link40and closure plate closure links36,37move forwardly, consequently moving the closure member28and firing bar43distally. As the slotted closure arm link40moves forwardly, the pall lug60of the release pall59slides on the clamp sliding surface56. The pall lug60engages the distal ends of the toggle arms69of the toggles68, and consequently pivots the toggles68in a clockwise direction. As the slotted arm closure link40continues to move forwardly in response to the pivotal movement of the closure trigger26toward the handgrip24, the pall lug60of the release pall59will eventually lodge into the intermediate detent57. Once positioned in the intermediate detent57, the closure spring42is incapable of returning the closure trigger26to its original, unactuated position. The closure trigger26is now in its intermediate, partially closed position, to properly position and retain tissue between the cartridge housing121and anvil122, as shown inFIG. 15. In addition, as the closure member28and firing bar43move distally, the apex52of the arcuate firing trigger link51slides on the sliding surface48of the proximal end section47of the firing bar43.

During the closing stroke from the open to the intermediate position the retaining pin mechanism100is activated. Forward movement of the closure member28moves the integral posts29distally. The posts29contact the L-shaped slot110of the yoke111. Hence, distal movement of the posts29cam the L-shaped slot110causing the yoke to pivot around pins112. The rotation brings bearing posts113on the yoke111into contact with camming surfaces114on the push rod driver104. Further rotational movement of the yoke111causes bearing posts113to move the push rod driver104distally through camming contact on surfaces114. The push rod driver104contacts the push rod102, moving the push rod102distally. The push rod102, in turn, moves the coupler133and retaining pin125distally. Completion of the closing stroke to the intermediate detent57position results in the retaining pin125moving distally through the hole144of the cartridge housing121, through hole159running through the washer123and anvil122and into the hole (not shown) in the supporting structure81. Tissue, which was disposed between the contact surface127of the cartridge housing121and the anvil122, is now trapped between retaining pin125and the guide pin124.

This same result can be obtained prior to closing by manual distal movement of saddle slide101. Slide movement will result in forward movement of the push rod102, coupler133and retaining pin125until the retaining pin125is fully disposed through the anvil122, washer123and hole89in the supporting structure81. Activation of the closing stroke after the retaining pin125has been manually moved forward would still result in the rotation of the yoke111as described above but without any additional movement of the retaining pin actuation mechanism100.

The closing stroke from the open to the intermediate detent57position moves the lockout lever181distally as it is attached to closure member28by the pin182as shown inFIG. 31(open) andFIG. 32(intermediate position). Distal movement of the lockout lever181causes the camming surface186to contact the lockout ledge85of the support81, resulting in the lockout lever181rotating clockwise and coming to slidable contact with base surface86of supporting structure81. In this position, the distal end185of the lockout lever181has rotated away from post188on driver131.

Referring now specifically toFIG. 16, when the closure trigger26is squeezed toward the handgrip24from the intermediate detent57position, the toggle arms69of the toggle68disengage from the pall lug60. Consequently, as the toggle68continues to rotate in a clockwise direction, the release pall lug60rides up the toggle arms69and with continued motion of the closure trigger26falls into the closure detent58. As the release pall59rides up the toggle arm69it rotates the release button61clockwise around pivot63. As the release pall60falls into closure detent58, it makes an audible clicking sound alerting the surgeon that closure position has been reached.

In addition, as the firing bar43continues to move forwardly, the apex52of the arcuate firing trigger link51comes into contact with the side engagement surface49of the proximal end section47of the firing bar43. Consequently, the firing trigger27is moving into a position where it can continue to move the firing bar43distally to fire staples after the tissue has been fully clamped. When the apex52of the arcuate firing trigger link51moves into engagement with the engagement surface49of the proximal end section47, the firing trigger27begins to pivotally rotate in a counterclockwise direction toward the hand grip24in response to the action of a torsion spring on the right hand side of the firing trigger27(torsion spring not shown). The firing trigger27pivots independently of the pivotal movement of the closure trigger26, but its pivotal rotation is blocked until the firing bar43has moved distally to enable engagement of the firing trigger link51with the terminal engagement surface of the firing bar43.

Turning specifically toFIG. 17, when the closure trigger47has been fully squeezed and it is adjacent the handgrip24, the pall lug60at the distal end of the release pall lodge59into the closure detent58. In the closure detent58position, the tissue has been fully clamped between the cartridge housing121and anvil122, and the closure spring42is incapable of returning the closure trigger26to its original position. Therefore, the closure trigger26is retained in the position shown inFIG. 4.

Concurrently with the counterclockwise motion of the closure trigger26, the firing trigger27continues to rotate counterclockwise by the action of the torsion firing bar return spring55until the firing trigger27is in a relatively vertical orientation with respect to the handle21of the linear surgical stapler20. In the fully clamped position, the apex52of the arcuate firing trigger link51has fully engaged the engagement surface of the proximal end section47of the firing bar43and, therefore, the firing trigger27is in a position to further move the firing bar43distally to fire staples into the tissue.

In the fully closed position the staple pockets128of the cartridge housing121are aligned with the staple-forming surface129of the anvil122as shown inFIG. 33. The retaining pin125has aligned the top of the anvil122and the cartridge housing121and the guide pin124has aligned the bottom of the cartridge housing121with the bottom of the anvil122.

As illustrated inFIG. 18andFIG. 34, the firing trigger27can be squeezed to pivotally rotate it toward the hand grip24until it is positioned adjacent the closure trigger26. During the pivotal rotation of the firing trigger27, the firing bar43moves distally, contacts the knife holder130. The resulting distal movement of the knife holder130results in contact with the knife126and driver131. Distal movement of the driver131results in the staples (not shown) to be distally advanced into the staple forming surfaces129of the anvil122resulting in staple formation of a generally B shape. The knife126distally advances in slots147of the guide pin124and the retaining pin125in conjunction with staple formation. These slots147guide the knife126onto the cutting surface157of cutting washer123resulting in the transection of any tissue caught between.

Release of manual pressure to the firing trigger27results in the firing bar return spring55to retract the firing bar43and returns the firing trigger27to the position shown inFIG. 17. This movement results in the retraction hook45retracting the retraction ledge173on the knife holder130and knife126. The resulting proximal movement retracts the knife126into the cartridge housing121as shown inFIG. 35. Detent post138on the knife holder130retracts into engagement with the detent139on the cartridge housing121to hold the knife holder130and knife126in this retracted position. The driver131is retained in its distal most (fired) position by engagement of the detent post140on the driver131engaging detent142of the cartridge slot137.

Should there be an interference on the knife126, as from the user cutting into another surgical instrument by mistake, such that the force from the firing bar return spring55is insufficient to retract the firing bar43and thus retract the knife126into the cartridge housing121, the user can manually retract the cutting system by pulling clockwise on the firing trigger27. The manual clockwise movement causes the arcuate firing trigger link51to rotate clockwise until it strikes a firing bar retraction tab71on the proximal end47of the firing bar43. The contact between the clockwise moving arcuate firing trigger link51and the firing bar retraction tab71causes the firing bar43to retract proximally and return to the position shown inFIG. 17. This in turn causes the retraction hook45retract the retraction ledge173on the knife holder130and knife126. Thus, this safety feature allows for the user to retract the cutting mechanism to a safe position and return the firing system to a position that would allow the linear surgical stapler20to be opened, as will now be described.

Referring toFIG. 19, when the surgeon depresses the release button61, the release pall59pivots about a release trunnion63in a clockwise direction to dislodge the pall lug60from the closure detent58position. As it is dislodged, the pall lug60rides on the toggle arms69to bypass the intermediate detent position57on clamp link40. In this manner, the closure and firing triggers26,27can return to their original, unactuated positions in response to the bias created from the closure spring42and firing bar return spring55. When the pall lug60rides on the toggle arms of the toggles68, the toggle arms69rotate counterclockwise as the closure and firing triggers26,27rotate in a clockwise direction to return to their original unactuated positions. Therefore, the surgeon can release the closure and firing triggers26,27so that they can return to the positions illustrated inFIG. 20without unnecessarily returning to the intermediate detent57position.

The release of the linear surgical stapler20to the open position shown inFIG. 20causes the closure member28and the attached lockout lever181to retract to the full open position as shown inFIG. 36. In this position the post188on the driver131is no longer disposed to hold down the lockout lever distal end185. The driver131, as described above, has been detented into place in the forward position by post140and the cartridge detent142. Hence, when the lockout lever181, whose proximal end184slides along support arm surface86, is fully retracted it is now free to rotate counter-clockwise and drop lockout groove187below ledge85on the C-shaped supporting structure81. The lockout lever181will remain in this position when the cartridge module120is removed as shown inFIG. 37.

Any future attempt to close the linear surgical stapler20which has been fired will result in the lockout groove187hooking into the ledge85as shown inFIG. 38, supplying feedback to the user of a previously fired device. This same feature will engage if the retainer160has been removed prior to loading and the cartridge module120has been misloaded without the cartridge module120being in the right position. In this case the driver post188would not be in the right position to move lockout lever181into the position to be cammed up onto surface86as described above. Similarly, a cartridge module120which has already been fired would also not release the lockout mechanism180. It is important to note that there is closure stroke travel allowed in the lockout mechanism180prior to engagement of the lockout groove187hooking into the ledge85. This travel indicates to the user that the device is not jammed due to some malfunction as might be the reaction if the lockout mechanism180had no travel. Hence, the user knows that the device is not jammed but incorrectly loaded when the lockout mechanism engages.

After release of the device back to the open position shown inFIGS. 1 and 2, the retaining pin mechanism100must be manually retracted by pulling proximally on saddle101. The retraction causes the retaining pin125to retract back into the cartridge housing121. At the completion of the manual retraction the fired cartridge module120can be unloaded and replaced with a new cartridge module120.