Surgical stapling apparatus

An endoscopic surgical apparatus is provided for placing lateral lines of surgical fasteners into body tissue. The apparatus includes a frame portion, an elongated portion extending from the frame portion, and an articulating fastener applying assembly associated with a distal end of the elongated portion. The fastener applying assembly includes a base portion, a staple cartridge housing, and an anvil member which has a forming surface thereon against which surgical fasteners are driven as they are ejected from the cartridge housing. A first mechanism is provided for effectuating the rotation of the fastener applying assembly about an axis defined by the body portion, a second mechanism is provided for effectuating the articulation of the fastener applying assembly, and a third mechanism is provided for independently rotating the cartridge housing and anvil member relative to a longitudinal axis defined by the base position to increase the range of operability of the apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical stapling apparatus, and more particularly, to surgical apparatus for performing sequential operations such as tissue clamping, staple forming and/or tissue cutting.

2. Description of Related Art

Surgical stapling apparatus are known wherein tissue is first grasped or clamped between opposing jaw structure and then fastened by means of fasteners. In some instruments a knife is provided to cut tissue which has been joined. The fasteners are typically in the form of surgical staples. However, two part polymeric type fasteners are also known.

Instruments for this purpose can comprise two elongated fingers which are respectively used to capture or clamp tissue. Typically, one of the fingers carries a disposable cartridge housing wherein a plurality of staples are arranged in at least two lateral rows while the other finger comprises an anvil for curling the staple legs into a hook-like configuration upon their being driven against the anvil. The stapling operation is effected by a pusher which travels longitudinally along the cartridge carrying finger, with the pusher acting upon the staples to place rows of staples in body tissue. A knife may be optionally positioned in such a manner so as to operate sequentially immediately behind the pusher, and laterally positioned between the staple rows to longitudinally cut and/or open the stapled tissue between the rows of staples. Such instruments are disclosed in Bobrov et al. (U.S. Pat. No. 3,079,606) and Green (U.S. Pat. No. 3,490,675). These instruments comprise apparatus for simultaneously making a longitudinal incision and applying a row of staples on both sides of the incision.

A later development disclosed in Green (U.S. Pat. No. 3,499,591) applies a double row of staples on each side of the incision. This is accomplished by a cartridge assembly wherein a cam member moves within a guide path between two sets of staggered staple carrying grooves. Staple drive members located within the grooves each have two staple pusher plates, and sloping surfaces disposed within the guide path so as to be contacted by the longitudinally moving cam and be driven along the groove to effect ejection of two staples.

The cartridge assemblies typically come in a plurality of sizes, each varying in both length and number of staples contained therein. Depending on the procedure to be performed, the surgeon must select the appropriate cartridge assembly. No provision is currently available to adjust the firing means of the instrument itself so that a wide variety of staple driving sequences may be accomplished using a single staple cartridge assembly.

The instruments described above were all designed to be used in surgical procedures wherein surgeons have direct manual access to the operation site. However, in endoscopic or laparoscopic procedures surgery is performed through a small incision or through narrow cannulae inserted through small entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, an endoscopic surgical stapling apparatus such as that shown in Green et al. (U.S. Pat. No. 5,040,715) has been developed. This apparatus is well suited for such procedures and incorporates a distal end having an anvil and staple cartridge assembly and a manually operated handle assembly interconnected by an endoscopic portion which permits the instrument to be inserted into a cannula and be remotely operated by the surgeon.

An object of the present invention is to provide a surgical apparatus that provides a full range of remotely actuated movements to the distal working members of the apparatus to facilitate interaction with and manipulation of tissue.

SUMMARY OF THE INVENTION

The surgical instrument in accordance with an embodiment of the present invention is a surgical stapling apparatus which is adapted for placing one or more longitudinal rows of staples. This apparatus may further include a knife for making an incision in body tissue between the rows of staples. The latter configuration may find particular use of adjoining two hollow organs or in removing an organ, such as the appendix, the gallbladder, etc.

In a preferred embodiment of the subject invention the endoscopic stapler comprises a frame portion, an elongated tubular body portion extending from the frame portion and adapted for receiving an articulating cartridge assembly. The articulating cartridge assembly includes a cartridge mounting portion removably maintained in a distal end portion of the tubular body portion and a cartridge housing portion which is pivotally connected to the cartridge mounting portion. A cable loop assembly is associated with the tubular body portion of the instrument for effectuating the articulation of the cartridge housing portion relative to the cartridge mounting portion of the cartridge assembly. The cable loop assembly includes a cable member, a pivot block member mounted for rotation in a distal end portion on the tubular body portion about an axis perpendicular to the longitudinal axis thereof, and a rotation control member operatively associated with the tubular body portion of the apparatus for manipulating the cable loop assembly. A cartridge element, which includes a plurality of surgical staples slidably mounted therein, and having a tissue engaging surface, is receivable within the cartridge housing portion of the cartridge assembly. An anvil member is also provided which has a staple forming surface formed thereon and which is mounted adjacent the cartridge housing portion of the cartridge assembly such that the anvil member is movable between an open position and a closed position wherein the staple forming surface is in close cooperative alignment with the tissue engaging surface of the cartridge element.

The apparatus further comprises means associated with the tubular body portion for moving the anvil member between the open and the closed positions, and means for ejecting the surgical staples from the cartridge element in such a manner so as to cause the staples to engage and form on the staple forming surface of the anvil member. The means for moving the anvil member comprises a linkage mechanism associated with the frame portion and extending into the tubular body portion to a cable mechanism. The cable mechanism includes a cable member mounted at a leading end thereof to the linkage mechanism and at a trailing end thereof to the cartridge housing portion of the cartridge assembly. The anvil member is operatively associated with the cable member intermediate the ends thereof. The means for ejecting the surgical fasteners comprises a plurality of pusher elements in abutment with the surgical fasteners, and at least one cam bar for actuating the pusher elements. The cam bar is mounted in an adapter which translates within the cartridge assembly. In one embodiment of the cartridge assembly, the cam bar is fixedly mounted in the adapter while in another embodiment the cam bar is freely movable within the adapter.

The articulating cartridge assembly of the subject invention is also provided with bearing means for guiding the translation of the cam bars as they traverse the cartridge assembly at such times when the cartridge housing portion of the cartridge assembly is articulated relative to the cartridge mounting portion thereof.

In another preferred embodiment of the surgical apparatus of the subject invention, the instrument includes a fastener applying assembly having a base portion and fastener applying means which include a staple cartridge housing and an anvil member. First means are provided for effectuating articulation of the fastener applying assembly between a first position generally in alignment with the longitudinal axis of the elongated body of the instrument and a second position angularly disposed with respect to the longitudinal axis of the elongated body. Second means are provided for effectuating rotation of the fastener applying assembly about the longitudinal axis defined by the elongated body relative to the frame portion. Third means are provided for effectuating independent rotation of the fastener applying means relative to the base portion of the fastener applying assembly to further increase the range of operability of the surgical apparatus of the subject invention.

The surgical apparatus of the subject invention may further comprise sealing means associated with the tubular body portion of the instrument for prohibiting the egress of insufflation gas therethrough during surgical procedures.

The surgical instrument may be constructed either as a reusable unit or as a single use, disposable unit or, alternatively may be formed with a reusable handle portion and replaceable body portions and/or staple carrying cartridges.

Further features of the invention, its nature, and various advantages will become more apparent from the accompanying drawings and the following detailed description of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is generally accepted that endoscopic procedures are more common than laparoscopic procedures. Accordingly, the present invention shall be discussed in terms of endoscopic procedures and apparatus. However, use herein of terms such as “endoscopic”, “endoscopically” and “endoscopic portion”, among others, should not be construed to limit the present invention to a stapling and cutting apparatus for use only in conjunction with an endoscopic tube. On the contrary, it is believed that the present invention may find use in any procedure where access is limited to a small incision, including but not limited to laparoscopic procedures. Also, as used herein the terms “fasteners” and “staples” shall be treated equivalently. Unless otherwise stated, the term “cartridge assembly” shall include at least the cartridge itself and staples or fasteners and staple drive members disposed therein.

In the drawings and the description which follows, as is customary, the term “proximal” refers to the end which is closest to the operator while the term “distal” will refer to the end which is furthest from the operator.

Referring toFIG. 1, a self contained gas powered endoscopic surgical apparatus constructed in accordance with the principles of the present invention is illustrated and is designated generally by reference numeral50. Surgical apparatus50essentially comprises a frame portion52and an elongated portion54. An anvil member56and an articulating cartridge assembly58are preferably removably mounted in a distal end portion60of elongated portion54. Anvil member56and cartridge assembly58are manually controlled by means of an articulating handle62associated with frame portion52. More particularly, handle62interconnects with anvil member56by means of a linkage and cable assembly which is associated with the elongated portion54such that when handle62is articulated from an open position (seeFIG. 3) to a closed position (see FIG.5), anvil member56is moved into close approximation with the articulating cartridge assembly58. This operation will be discussed in greater detail hereinbelow.

Turning now toFIG. 2, the frame portion52of surgical apparatus50includes opposed first and second housing members64and66which enclose a pneumatic system designated generally by reference numeral68. The distal end portion of articulating handle member62is pivotally connected to a clamp tube70at a pivot point72. Longitudinal grooves74are formed in the opposed first and second housing members64and66adjacent pivot point72for slidably receiving molded shuttles76which are attached to the articulating handle member62at pivot point72. The molded shuttles76are pivotally connected to either side of the pivot point72on the distal end of handle62and function to guide the distal end thereof in a longitudinally distal direction as handle62is articulated.

A pair of articulating links78interconnect an intermediate portion of handle member62to a pair of projections80formed on an upper surface of housing members64and66respectively. A handle return spring82extends between handle62and housing members64and66by means of a pair of spring anchor pins84, one of which is disposed in handle62and the other extending between projections80. Anchor pins84also serve to pivotally connect articulating links78to projections80. This spring82assists in returning handle62from its closed position to its open position.

The proximal end of articulating handle62is preferably diagonally formed away from housing members64and66so as to enable the surgeon to more easily release the handle62from its closed position. This is done by placing the hand under the proximal end of handle62and lifting. A texturized or serrated portion86may be advantageously formed on an under surface of the proximal end of handle62to enhance the gripping thereof.

Pneumatic system68is wholly contained within housing members64and66and includes a container88of relatively low pressure gas longitudinally slidably mounted therein. The pressure of the gas in container88during operation of the stapler is typically less than about 200 p.s.i.g. and preferably in the range from about 80 p.s.i.g. to about 160 p.s.i.g. Any suitable non-toxic gas can be used including but not limited to halogenated hydrocarbons which are gaseous at room temperature, e.g., fluorinated hydrocarbons such as Freon 12 or chlorinated hydrocarbons such as Freon 152A. Container88dispenses the relatively low pressure gas through stem90, valve92, and gas tube94when the firing trigger96is depressed. Spring97is positioned between container88and valve92and functions to hold the container88in a position spaced from valve92. Valve92is fixed within housing members64and66and is longitudinally adjustable by means of set screw93(see FIG.11). This feature permits the position of valve92to be longitudinally changed to compensate for manufacturers variations in length among containers88between a distal end and the proximal end of stem90. A pneumatic actuator98is disposed above container88within housing members64and66. Actuator98includes a pneumatic cylinder100which is held in place by opposed pins99. Cylinder100is substantially closed at the proximal end thereof but for a ferrule102extending therethrough and is open at its distal end, wherein a pneumatic piston104is mounted for reciprocal motion therein on an axis which is parallel to the longitudinal axis of elongated portion54. Cylinder100is preferably circular in transverse cross-section, however, other configurations would function acceptably well.

Piston104is pneumatically sealed to cylinder100by an O-ring106molded of polyethylene or the like. Gas dispensed from container88is supplied to pneumatic actuator98via gas tube94which admits the gas to cylinder100through ferrule102behind piston104to drive piston104distally in the cylinder100. The distal end of piston104is adapted to engage the firing mechanism of the surgical apparatus as will be described in greater detail below.

Referring toFIGS. 2-10, firing trigger96is pivotally mounted in a proximal end of housing members64and66by a pivot pin108. A spring110is positioned adjacent pin108which serves to bias firing trigger96proximally into the prefiring position. A trigger rod112extends distally from firing trigger96in a longitudinal direction so as to engage a piston slide114which is positioned in a lower portion of piston104. Piston slide114comprises a substantially U-shaped channel which fits into a corresponding groove116formed in piston104. Piston slide114is spring loaded in a proximal direction by a spring118and includes a transverse projection120on a lower distal end thereof which engages the distal end of trigger rod112.

A rocking lever120is pivotally mounted on a transverse slide pin122and is adapted for transverse movement relative to slide pin122between an engaged position prior to firing (seeFIGS. 5-7) and a disengaged position when articulating handle62is open (see FIGS.3and4). A cam slide124is vertically mounted in first housing member64for reciprocal movement between an upper position and lower position (seeFIGS. 4 and 6, respectively). Cam slide124functions to move rocking lever120between the engaged position (FIG. 6) and the disengaged position (FIG.4). Thus, until articulating handle member62is closed, causing cam slide124to move rocking lever120into the engaged position, surgical instrument50cannot be fired.

Cam slide124is normally biased in its upper disengaged position by a cam slide spring126which is mounted in vertical groove128formed in the first housing member64(see FIGS.3and4). In this upper position, cam slide124extends upward beyond first housing member64to engage articulating handle member62as it is moved to a closed position (see FIGS.5and6). Cam slide124further includes a camming surface130which contacts a corresponding camming surface of a camming block132which is mounted on slide pin122. Camming block132is loaded against cam slide124by a slide spring134and moves rocking lever120transversely on slide pin122between an engaged position and a disengaged position. As articulating handle62is compressed toward housing members64and66in the direction of arrow135it contacts cam slide124, moving it downward, and causing camming surface130to move camming block132and rocking lever120transversely into an engaged position in alignment with piston104.

Turning toFIGS. 3,5-7and9, once the articulating handle62has been fully compressed, rocking lever120is disposed in alignment with piston slide114and can be pivotally moved about transverse slide pin122to engage a pusher disk136disposed at the distal end of container88. When the instrument is in the clamped configuration, depression of firing trigger96moves trigger rod112distally in the longitudinal direction causing piston slide144to engage and pivot rocking lever120which, in turn, engages pusher disk136and moves container88into contact with valve92to dispense gas and propel piston104in the distal direction (see FIGS.9-11).

As piston104moves distally, rocking lever120remains in its pivoted firing position by contact with the bottom surface of piston104. A gap138is formed in the bottom surface of piston104adjacent the proximal end thereof which effectively allows rocking lever120to disengage from piston104and return to a position wherein container88is released from engagement with valve92, thereby stopping the flow of gas into pneumatic cylinder100.

A pair of return springs140and142disposed in elongated portion54drive piston104back to its initial prefired position. A camming surface144is formed in a distal end of gap138which causes rocking lever120to move out of engagement with piston104as it returns and rocking lever120moves to its original prefired position (see FIG.5).

Referring toFIG. 12, another embodiment of frame portion52is illustrated which includes annular rings150and152both of which are provided between the distal end of frame52and the proximal end of elongated portion54. In addition to the reduction in egress of insufflation gas resulting from the close tolerances and interfitting of structural elements within frame portion52and/or elongated portion54, these rings150,152further inhibit the escape of insufflation gas from the operative site. Additionally, rings154and156are positioned adjacent the proximal and distal ends, respectively, of clamp tube70to effectively seal off insufflation gas from the area of piston104.

This embodiment of frame portion52further comprises a counter mechanism including a counter ratchet160attached to trigger rod112, and a leaf spring162which is mounted in housing66so as to engage teeth formed on the bottom surface of counter ratchet160. Numerical indicators are disposed in longitudinal spaced apart relationship on an outer surface of the counter ratchet160and correspond to the number of times apparatus50has been fired. An access plate164having a viewing window166therein is positioned in the outside surface of housing member66to facilitate observation of the counter mechanism.

In operation, each time the instrument is fired the leaf spring162engages a respective proximally located tooth of the counter ratchet160, effectively sliding the counter ratchet160distally to align the next lower number in viewing window166. The counter mechanism of this embodiment further includes a locking feature whereby the trigger button96is retained in the fired position when the leaf spring162engages the most proximal surface of the counter ratchet160and prevents the firing rod112from returning to its proximal unfired position.

This embodiment of frame portion52further includes an integral trigger button rotary safety mechanism comprising a rotary safety shaft168disposed within a roller170. The rotary safety mechanism is rotatably positioned in trigger button96with the roller170extending out beyond the plane of the back surface of trigger button96. Projections172are eccentrically formed on both sides of rotary safety shaft168and extend out beyond the plane of the side surfaces of the trigger button96. A spring174functions to bias the rotary safety mechanism such that projections172are disposed in their distalmost orientation.

Referring now toFIGS. 13 and 14, in the instrument's unfired position projections172are in their distalmost position and are disposed in direct alignment with the proximal ends of the housing members64and66. In this position, trigger button96cannot be accidentally depressed to fire the instrument. In order to disengage the safety mechanism, the roller170is moved in the direction of arrow176so as to rotate projections172from their distalmost position to their proxinalmost position effectively allowing trigger button96to be depressed to fire the instrument. As soon as roller170is released, spring174returns the safety mechanism to its normal position so as to prevent subsequent accidental firings.

Turning toFIG. 15, the elongated portion54of surgical apparatus50is illustrated in exploded detail. At a proximal end of elongated portion54, piston104extends through clamp tube70(FIG. 12) and into the proximal end of a cover tube182. Piston104is adapted for reciprocal movement within clamp tube70in response to actuation of pneumatic system68. The distal end of piston104is provided with an attachment flange184for mounting a plurality of pusher washers186of the type which are well suited for high loads in small spaces. A spring support washer188is positioned on flange184for engaging the proximal ends of inner and outer return springs140and142. A lock washer189maintains the pusher washers186in a desired position on flange184. Attachment flange184has a chamfered distal tip and is configured and dimensioned to be received between the proximal opposed fingers190and191of a channel member192.

As shown inFIG. 15, channel member192is defined by an elongated structure which is slidably mounted in elongated portion54for reciprocal longitudinal motion therein. As mentioned above, channel192has opposed fingers190and191at a proximal end thereof to receive attachment flange184of piston104. A forked portion194is provided at a distal end portion of channel192defining a slot196therebetween. Forked portion194has a pair of opposed ramping surfaces198and200, the function of which will be described in greater detail below.

An extension sleeve204is disposed within cover tube182and is fixed on a proximal end thereof to clamp tube70. A sealing member206is mounted adjacent clamp tube70for sealably isolating frame portion52of instrument50from elongated portion54thereof. Inner and outer return springs,142and140respectively, are contained within upper extension spacer210and lower extension spacer212which are, in turn, combined and fixed within the extension sleeve204. Spring support washer188abuts the proximal ends of inner and outer return springs142and140and, when instrument50is fired, transmits the energy of the compressed springs142and140to the piston104, returning it to its prefired position.

A support structure214is also disposed within extension spacers210and212adjacent the distal end thereof which functions to releasably receive cartridge assemblies in instrument50. Support structure214is retained in place within combined extension spacers210,212by a transverse support key216. A clamp lockout structure is incorporated into support structure214and upper extension spacer210. The clamp lockout structure comprises a leaf spring220having a diagonally downwardly extending projection222attached thereto. A slot224is formed through the top surface of support structure214and is adapted to engage and receive projection222whenever the support structure is not longitudinally aligned. This clamp lockout structure is designed and configured to prevent the instrument jaws from closing on tissue unless the cartridge and/or jaw elements are properly emplaced within the elongated portion54of apparatus50.

Referring now toFIG. 16 and 17, anvil member56of surgical apparatus50comprises an elongated distal body portion230and a proximal mounting shroud232. Body portion230defines a staple forming plate234(seeFIG. 17) having a plurality of staple forming depressions236provided therein into which staples are driven so as to be formed. A longitudinal center groove238is also provided in staple forming plate234to facilitate the guided passage of a surgical knife240during a firing sequence of apparatus50. Mounting shroud portion232is defined by opposed side walls242and244which are dimensioned to fit cooperatively upon a portion of cartridge assembly58. Apertures246are included in the opposed side walls242and244for mounting a cylindrical pulley248. Pulley248is maintained within shroud portion232by opposed fastener ring pairs250and252and functions in cooperation with a mechanism for moving anvil member56between an open position and a closed position. A pair of opposed spaced apart arms254and256extend longitudinally from the proximal end of shroud portion232and have vertical mounting slots258and260provided therein, respectively, for receiving a mounting pin262. Mounting slots256and258enable anvil member56to adjust its position upon engaging tissue against forming plate234. More particularly, slots256and258permit adjustment of the spacing between forming plate234and cartridge assembly58.

The articulating cartridge assembly58of the subject invention comprises a forward housing portion270and a rearward housing portion272. Forward housing270is defined by a channel structure of substantially rectangular cross-section having opposed side walls274and276and a bottom wall278. This channel structure constitutes the cartridge receiving portion and is dimensioned to receive a cartridge280. A longitudinal groove structure282is defined in cartridge280for receiving and guiding knife240therethrough. A plurality of stems283extend downwardly from the undersurface of cartridge280for engagement in a plurality of corresponding apertures287formed in the bottom wall278of forward housing270. A plurality of pusher elements284are disposed in cartridge280in abutment with a plurality of corresponding staples285. The staples285are advantageously arranged in six longitudinal rows with three rows positioned on either side of groove structure282. See, U.S. Pat. No. 4,978,049 to Green, the disclosure of which is incorporated herein by reference. In addition, two pairs of longitudinal slots are formed in the cartridge housing280and are adapted to receive a pair of dual cam bars286and288therein. Cam bars286and288each serve to drive three corresponding longitudinal rows of staples285.

Cam bars286and288are each provided with a cam surface290in an upper distal end thereof and an overhanging ledge292with vertical surface294in a lower distal end. This overhanging ledge292is dimensioned to extend into the longitudinal slots formed in cartridge280to a point wherein the vertical surface294of overhanging ledge292drops down and abuts the forward edge296of the forward housing portion270cartridge assembly58when cam bars286and288move to their distal fired position. At their proximal ends, cam bars286and288are provided with hook structure298for releasably engaging a cam bar adapter300.

Referring now toFIGS. 16,19, and23, one embodiment of cam bar adapter300in accordance with the present invention is illustrated. Cam bar adapter300comprises a forward section302and a rearward section304. Forward section302is substantially rectangular in configuration and has a central longitudinal groove306formed therein and dimensioned to receive the longitudinal groove structure282on cartridge280when cam bar adapter300is urged to its forwardmost position. Flanges308and shelves310function to removably retain the proximal ends of cam bars286and288. The rearward section304of cam bar adapter300is rectangular in configuration with projections312formed in the proximal end thereof. The rearward section is dimensioned to be receivable within the slot formed in forked portion194in channel member192. Projections312are dimensioned to engage ramping surface198so as to allow forked portion194to ride up and over projections312when it is moved in the distal direction. A vertical bore314and a longitudinal groove316are formed in the rearward section304of cam bar adapter300which retain and hold the shank portion315of knife240.

Although cam bar adapter300is effective to maintain cam bars286and288and to transport the same through cartridge assembly58, it may be desirable to provide a cam bar adapter which enables the proximal ends of cam bars286and288to move freely in a transverse direction while being effectively maintained in a desired longitudinal position. Free mounting of the cam bars provides several advantages over fixed mounting which advantages will be discussed in detail hereinbelow.FIGS. 20-22illustrate this embodiment of the cam bar adapter and is designated generally by reference numeral320. Cam bar adapter320comprises a cam bar support fixture322and a housing structure324. Support fixture322is defined by a substantially L-shaped structure having an elongated leg portion326and a transverse leg portion328. A slot330is provided in leg portion326for receiving the proximal end of dual cam bar286and a similar slot322is provided in leg portion328for receiving the proximal end of dual cam bar288. The staggered mounting of cam bars286and288in L-shaped support structure322advantageously positions cam bars286and288to more effectively eject the staples from cartridge285. Support fixture322is dimensioned so as to fit within a rectangular channel334defined within housing structure324. Channel334accommodates support fixture302in such a manner so that it can move freely therein.

The advantages of freely mounting cam bars286and288are best explained with reference toFIGS. 23 and 24. Cam bar adapter300is illustrated inFIG. 24, wherein the respective proximal portions of cam bars286and288are fixedly mounted. Upon articulating the forward housing270of cartridge assembly58, cam bars286and288are compressed by opposed bearing members340and342disposed in forward housing270. The compression of the cam bars286and288causes a buckling effect at the central spans thereof. The deflection is accentuated because the proximal end portions of cam bars286and288are fixed in cam bar adapter300. In contrast, if cam bars286and288are mounted in cam bar adapter320such that the respective proximal end portions thereof are maintained in the L-shaped support fixture322which moves freely within channel334defined in housing structure324, the degree of deflection or buckling across the central spans of cam bars286and288is substantially decreased. By reducing the degree of deflection across the spans of cam bars286and288, the amount of force needed to drive cam bars286and288is also decreased. Moreover, the amount of pressure required to be released by the pneumatic system for driving cam bars286and288through a complete stroke will be less when the respective proximal end portions of cam bars286and288are mounted freely rather than fixedly in a cam bar adapter.

The cam bars are often made of stainless steel, however, it has been found that forming the cam bars from a shape memory alloy comprising, for example, a composition of nickel and titanium (such a composition is available from Raychem Corp., Menlo Park, Calif. under the trade name TINEL), rather than stainless steel, will reduce the amount of force required to drive cam bars286and288through a firing sequence.

Referring toFIGS. 18,19,23, and24, bearings340and342are mounted in a pair of opposed ports344and346provided in-the opposed side walls274and276respectively, adjacent the proximal end of forward housing270. Bearing members340and342have a truncated triangular configuration defining a planar bearing surface for guiding cam bars286and288as they traverse cartridge assembly58at such times when it is in an articulated position and, in addition, compress the cam bars as they travel into cartridge280as discussed above.

Referring again toFIGS. 20-22, housing structure324of cam bar adapter320is further provided with a pair of spaced apart apertures350and352for retaining a pair of corresponding prongs354and356formed on the shank358of knife240. The rearward section360of housing structure324is of rectangular configuration and defines a structure for engaging groove196in channel member192. Seats362and364are provided on either side of rearward section360for engaging the forked portion194of channel member192.

Referring again toFIGS. 16,18and19, a flange366extends outwardly from the proximal end of the bottom wall278of forward housing270and includes an aperture368for receiving a rivet370. Rivet370also extends through an aperture372provide in a flange374which extends outwardly from the distal end of rearward housing272. This rivet connection enables forward housing270to articulate relative to rearward housing272.

Rearward housing272is defined by a channel of U-shaped cross-section having opposed side walls376and378and a bottom wall380. Locking slots382and384are formed in the opposed side walls376and378adjacent the proximal end thereof for engaging and retaining support structure214(see FIG.15). A pair of opposed crimps386and388are provided in opposed side walls376and378adjacent locking slots382and384for establishing a friction fit with cam bar adapter300(or in the alternative cam bar adapter320) within which the dual cam bars286and288are mounted.

Referring now toFIGS. 15,16, and28, the movement of anvil member56relative to cartridge assembly58in this embodiment is achieved through a linkage and cable system. This system includes a tube collar400which mounts on the distal end of combined upper and lower extension spacers210,212. Tube collar400has an internal partition wall402formed therein through which extends an aperture having a diameter which permits the passage of a cable404therethrough, while prohibiting the passage of an anchor ball406which is fastened to the trailing end of cable404. As it extends from partition wall402, the line of action of cable404is reversed from a proximal direction to a distal direction by turning about a pulley assembly which includes an annular pulley410mounted on a pulley shaft412, and retained thereon by a locking ring414. Pulley shaft412is supported in an aperture416provided adjacent the proximal end of support structure214. Upon turning about pulley410, cable404extends back through tube collar400, avoiding partition wall402and thereafter extending through a mounting collar418positioned on the distal end of outer cover tube182of elongated portion54. Cable404then extends through a longitudinal bore hole420formed in a pivot block422. Pivot block422is rotatably mounted on a flange424extending from mounting collar418by a threaded fastener426maintained in threaded aperture425. Threaded fastener426extends through an aperture428which is provided in flange424. The function and structure of pivot block422will be discussed in greater detail below with respect to the mechanism for articulating cartridge assembly58. After passing through bore hole420in pivot block422, cable404turns about cylindrical pulley248which translates the line of action of cable404in a direction perpendicular to the longitudinal axis of elongated portion54. The cable404is terminated at the trailing end thereof at an upper face of a cable separation block424. A U-shaped anchor cable427extends from the opposed face of cable separator block424and is dimensioned and configured to engage the forward housing270of articulating cartridge assembly58so as to anchor the cable mechanism. Preferably, a cover tube, which may be formed of aluminum or a like material, clothes anchor cable427.

The position of cable separator block424with respect to cylindrical pulley248can vary. For example, cable separator block424can be disposed proximal to pulley248as illustrated in FIG.36. In this instance, the cylindrical pulley248would be configured with a pair of spaced apart annular grooves or tracks for accommodating the U-shaped anchor cable427.

During operation of apparatus50, reciprocating movement of the combined extension spacer210,212in response to articulation of handle member62in frame portion52, will cause corresponding translation of tube collar400, thereby causing cable404to move in a longitudinal direction about annular pulley410, and subsequently about cylindrical pulley248in a perpendicular direction. As the trailing end of cable404moves about pulley248, it exerts a force thereupon which consequently causes anvil member56to move relative to the cartridge assembly58.

Apparatus50further comprises a mechanism for effectuating the articulation of the forward housing270relative to the rearward housing272of cartridge assembly58. The articulation mechanism includes, as stated previously, pivot block422. As best seen inFIGS. 25-27, pivot block422comprises a substantially rectangular body portion430through which extends longitudinal bore hole420, and a transverse bore hole432for receiving pivot pin262about which anvil member56pivots when the cable and linkage system is employed as described hereinabove. A longitudinal groove434is provided in the undersurface of body portion430for permitting passage of knife240as it traverses cartridge assembly58mounted upon cam bar adapter300. A fixed capstan436comprising a shaft portion438and a hood portion440extends upwardly from the body portion430of pivot block422about which an articulation cable442of looped configuration is supported. More particularly, cable442has an anchor ball444intermediate its length which is dimensioned and configured to be fixed within a port446formed in shaft portion438of capstan436(see FIG.26.).

As best seen inFIG. 27, the walls of longitudinal bore hole420diverge 45° from the central axis thereof at a central point within body portion432so as to define a mouth448at the proximal face450of pivot block422. The diverging mouth448of longitudinal bore hole420enables the relative movement of cable404during articulating movement of cartridge assembly58within a 90° sector of translation wherein ΘAand ΘBare each equal to 45°. It is also envisioned that, where a wider section of translation is desired, pivot block422and any associated structural elements of the apparatus may be modified to achieve at least 60° of articulation in either direction relative to the longitudinal axis of the instrument. The section of articulation cable442opposite anchor ball444is connected to a dial member452which is provided in the elongated portion54adjacent the proximal end thereof. Rotation of dial member452in either the clockwise or counter clockwise direction (seeFIGS. 31 and 32, respectively) will cause articulating cable442to translate in such a manner so as to cause pivot block422to rotate on an axis perpendicular to the longitudinal axis of elongated portion54about threaded fastener426. Consequently, anvil member56, which is connected to pivot block422through pin member262, and forward housing270which is operatively associated with anvil member56through U-shaped anchor cable427, is caused to pivot about rivet member370.

In use, the elongated portion54of instrument50is inserted into the body, preferably through an endoscopic tube. It is further preferred that the endoscopic tube apparatus be capable of maintaining a sealed pneumoperitoneum, with the internal sealing member of the housing further maintaining this seal despite introduction of the instrument in accordance with the invention into the endoscopic tube. As a practical matter, the jaws of the instrument are closed for insertion into the endoscopic tube, either by pinching the anvil and cartridge prior to insertion or by closing the articulating handle to cam the jaws closed prior to insertion.

Referring toFIGS. 29 and 30, with the instrument properly oriented so that the tissue to be fastened is disposed between the open jaws of the instrument, i.e., between the tissue contacting surfaces of anvil member56and cartridge280, the jaws are closed to clamp the tissue. Closure of the jaws is achieved as the surgeon presses down on articulating handle member62, so as to slide tube collar400distally, via clamp tube70, extension sleeve204, and extension spacers210,212.

The leading end of cable404is drawn in a distal direction as anchor ball406is maintained against partition wall402. As the leading end of cable404is drawn distally, the intermediate section thereof which is turned about annular pulley410is drawn in a proximal direction. Consequently, the trailing end of cable404is urged in an upward direction, perpendicular to the longitudinal axis of elongated portion54, as it turns about cylindrical pulley248, thereby exerting a downward force upon pulley248and urging anvil member56to approximate toward the tissue engaging surface of cartridge assembly58.

Where articulation is necessary or desired to orient the jaws prior to clamping, the forward housing270of cartridge assembly58may be articulated relative to the elongated portion54of apparatus50within a 90° sector of rotation, and in particular within a 45° sector of rotation on either side of the longitudinal axis of the elongated portion54of apparatus50. Referring toFIG. 31, clockwise rotation of dial member452will result in clockwise articulation of forward housing270and anvil member58. In particular, as dial member452is rotated, the lateral portions of articulation cable loop426translate in opposite longitudinal directions causing anchor ball444mounted in the shaft portion438of fixed capstan436of pivot block422to urge pivot block422in such a manner so as to rotate in a clockwise direction about threaded fastener426. At such a time, the forward housing270pivots about rivet370relative to the rearward mounting portion272of cartridge assembly58. Similarly, rotation of dial member452in a counter-clockwise direction as shown inFIG. 32, will articulate cartridge assembly.

After closing the instrument jaws, the instrument is ready to be fired. When the surgeon is ready to emplace the staples and cut tissue, firing trigger96is5depressed to actuate the pneumatic actuator98as discussed in detail above. Piston104, attached to the proximal end of channel192is driven distally causing the camming surface of forked portion194to ride up and over projection362of the cam bar adapter300and drive the cam bar adapter in a distal direction. Thereupon, the cam bars286and288and knife240are driven longitudinally through the cartridge to sequentially drive and form staples.

As piston104contacts return springs140,142, pusher washers186are compressed on themselves and serve to store energy as the piston moves distally toward the cartridge assembly. This initial compression occurs in the range of between about 20 p.s.i. to about 150 p.s.i. and preferably within a range of about 30 p.s.i. to about 60 p.s.i. Near the end of the distal stroke of the piston104, this stored energy is released to drive the cam bars286and288through the final distal limits of their travel within the longitudinal slots in the cartridge250. At the distal extreme of the longitudinal stroke, the overhanging ledges292of cam bars286and288drop over the edge of the forward cartridge housing270thus abutting vertical surface thereof.

Referring toFIGS. 33 and 35, after firing, return springs140,142engage piston104and return it to its original position. The return motion of piston104causes rocking lever120to be cammed aside by camming surface144of piston104. Subsequently, the L-shaped support fixture and cam bars286and288are pulled out of cam bar adapter320and remain in position in the longitudinal slots of the cartridge280. The cam bar adapter320, with knife240attached, moves proximally within rearward cartridge mounting portion272until the outer edges of cam bar adapter320impinge on crimps296.

The cam bar adapter320is held in place by crimps296while camming surfaces198and200of forked portion194causes the fork to ride up and disengage with projections312of the cam bar adapter300. Channel member192continues to move in the proximal direction until it reaches its rest position. At this point, the entire cartridge assembly58is deactivated.

In the event that the surgeon should accidentally attempt to again fire the instrument without replacing the deactivated cartridge with a new unfired cartridge, the resulting distal longitudinal motion of the channel192moves abutting structure202into contact with rearward projection290effectively preventing further movement of forked portion194toward cam bar adapter280.

After firing, articulating handle62is raised with the assistance of handle return spring82which action retracts collar tube400. This retraction causes anvil56to move of engagement with cartridge assembly58. Similarly, raising of articulating handle62causes cam slide124to move upward disengaging the pneumatic firing mechanism.

In order to replace the articulating cartridge assembly58, the instrument is withdrawn from the patient. Thereafter, the cartridge assembly is removed from the elongated portion54of apparatus50. To reinsert a new cartridge assembly, the proximal mounting portion272of cartridge assembly58is inserted into the distal end of elongated portion54. The instrument is now ready for reinsertion and continued use.

Turning now toFIGS. 36 and 38, another preferred embodiment of the surgical apparatus of the subject invention is illustrated and is designated generally by reference numeral500. Surgical apparatus500functions in much the same manner as the surgical instrument50previously described, with the exception of the mechanism for effectuating the articulation of the cartridge assembly58. Specifically, the articulation mechanism of surgical apparatus500comprises two assemblies, including a parallel crank linkage assembly505disposed adjacent the cartridge assembly58at the distal end of elongated portion54, and an actuation assembly, shown generally at510, located adjacent the frame portion52of the apparatus at the proximal end of elongated portion54. In the discussion which follows, both the linkage assembly505and the axial barrel cam assembly510will be described with respect to various embodiments. It will be appreciated however, by those having ordinary skill in the art, that any of the assemblies described herein may be modified to incorporate features shown in the various preferred embodiments.

Turning toFIGS. 40-42, the parallel crank linkage assembly505of surgical apparatus500is associated with a mounting collar512having an engaging portion514adapted for mounting within the distal end of cover tube182. The linkage assembly505includes a proximal crank member516mounted for rotation about a pivot pin518which extends through the rearward flange portion520of mounting collar512. Pivot pin518is disposed perpendicular to the longitudinal axis of elongated portion54. Longitudinally spaced from proximal crank member516, a distal crank member522is mounted for rotation about a pivot pin524. Pivot pin524extends through the forward flange portion526of mounting collar512and is disposed parallel to pivot pin518. Distal crank522is associated with a pivot block528having a longitudinal bore530extending therethrough for accommodating cable404. As previously described herein, cable404is associated with moving anvil member56between an open position and a closed position for clamping tissue. Pivot block528is also provided with a transverse bore532for accommodating the transverse pin262about which anvil member56pivots as it is moved between its open and closed positions.

Linkage assembly505further comprises a pair of parallel coupler links534and536which operatively interconnect the proximal crank member516and distal crank member522. Link534has a longitudinal span538with a transverse engaging slot540formed at a distal end thereof for engaging a pin542associated with distal crank522, and a transverse engaging slot544is provided at the proximal end thereof for engaging another pin546associated with the proximal crank516. Similarly, link536has a longitudinal span548with a transverse engaging slot550provided at the distal end thereof for engaging a pin552associated with the distal crank member522, and a transverse slot554is formed at the proximal end thereof for engaging yet another pin556disposed on the proximal crank member516. Of the two coupler links534and536, link534defines a driver link, while link536defines a follower link. Moreover, driver link536is provided with a coupling558, which depends from the undersurface thereof, intermediate span538for receiving and mounting the distal end of an elongated transmission rod560. Transmission rod560extends through the elongated portion54of surgical apparatus500for transmitting reciprocal longitudinal motion to driver link534in response to manipulation of the axial barrel cam assembly510. Transverse slots540,544,550, and554permit coupler links534and536to remain parallel to a longitudinal axis of the linkage assembly505during transmission of the reciprocal longitudinal motion by rod560.

Referring again toFIGS. 36-39, the actuation assembly510of surgical apparatus500comprises a generally cylindrical manipulator sleeve562disposed about the proximal section of elongated portion54. Manipulator sleeve562is configured and dimensioned for axial movement with respect to the longitudinal axis of elongated portion54. In particular, manipulator sleeve562may be rotated about the longitudinal axis of elongated portion54to rotate the cartridge assembly58relative to the frame portion52of apparatus500, and reciprocally in a generally longitudinal direction for effectuating the articulation of cartridge assembly58so as to increase the range of S operability of the instrument, which will be described in greater detail hereinbelow.

A barrel cam564having a substantially hemi-cylindrical configuration is associated with manipulator sleeve562and is configured and dimensioned for rotational movement as sleeve562is manipulated in a longitudinal direction to drive transmission rod560. Relative rotational movement of barrel cam564is facilitated by the interaction of a cam follower pin566extending radially inward from manipulator sleeve562, and a cam slot568defined in barrel cam564. Cam slot568has a three stage configuration including an upper step region570, a central step region572, and a lower step region574. When articulating the cartridge assembly58of surgical apparatus500in a counterclockwise direction, sleeve562is manipulated in a proximal direction, moving cam follower pin566from the central step region572, wherein cartridge assembly58is in substantial longitudinal alignment with the elongated portion54of the instrument, to the upper step region570of cam slot568, to axially rotate barrel cam564.

To articulate cartridge assembly58in clockwise direction, sleeve562is manipulated in a distal direction, moving cam follower pin566to the lower step region574of cam slot568, and thereby axially rotating barrel cam564. The longitudinal dimension of cam slot568can be modified depending upon the tactile sensation desired to be transmitted to the user of the instrument. In addition, an annular rib563(seeFIG. 38) extending radially outward from the cover tube182of elongated portion54, distal to manipulator sleeve562, serves to prevent over-insertion of the elongated portion54of surgical apparatus500into a trocar or cannula device.

As stated briefly above, the rotational movement of barrel cam564is conveyed to transmission rod560for effectuating the articulation of cartridge assembly58. This conveyance of rotational motion is accomplished by engaging an arm580formed at the proximal end of transmission rod560within an angled drive slot582defined in barrel cam564. Thus, as barrel cam564rotates in response to the translation of cam follower pin566within cam slot568, transmission rod560is advantageously driven in a longitudinal direction as the peripheral walls of angled drive slot582are urged against the engaging arm580thereof. To secure the engagement of arm580within angled drive slot582, a connective fitting584is mounted atop engagement arm576and is configured and dimensioned to move within longitudinal channel585formed in an inner surface of manipulation sleeve562.

Barrel cam564is also provided with a pair of spaced apart transverse alignment slots586and588which are adapted and configured for cooperatively receiving a pair of guide pins590and592. Guide pins590and592are associated with the outer tube182of elongated portion54and inhibit undesirable longitudinal shifting of the barrel cam564which may arise as sleeve562is manipulated. In addition, guide pins590and592achieve connection between the outer tube182of elongated portion54and the manipulator sleeve662via the interaction of cam follower pin566and cam slot568. This connection is further assisted by the provision of a spring loaded locking mechanism associated with manipulator sleeve562.

As best seen inFIGS. 37 and 39, the locking mechanism includes a lock ball594which is biased by a coiled spring596maintained within a cavity598formed within manipulator sleeve562. Lock ball594is selectively engageable within a plurality of spaced apart notches disposed about the outer circumference of cover tube182and including a primary notch600corresponding to the cam follower pin566being disposed in the upper step region570of cam slot568, a secondary notch602corresponding to cam follower pin566being disposed in the central step region572of5cam slot568, and a tertiary notch603corresponding to cam follower pin566being disposed in the lower step region574of cam slot568. By lockingly engaging the cover tube182of elongated portion54, rotation of manipulator sleeve562about the longitudinal axis of elongated portion54will effectuate remote rotation of cartridge assembly58relative to the frame portion52of surgical apparatus500.

In use, as sleeve562is manipulated in a distal direction (see FIG.38), transmission rod560will translate in a proximal direction with respect to elongated portion54, pulling driver link534proximally as indicated by arrow “A” in FIG.43. In response, distal crank member522is rotated about pivot pin524, thereby turning pivot block528in a clockwise direction. As pivot block528is operatively connected to anvil member56through transverse pin262, the forward housing270of cartridge assembly58is caused to articulate in a clockwise direction. Similarly, in response to manipulation of sleeve562in a proximal direction (see FIG.36), transmission rod560will translate distally with respect to elongated portion54, pushing driver link534distally as indicated by arrow “B” in FIG.44. As a result, distal crank member522will turn pivot block528in a counter-clockwise direction, articulating the forward housing270of cartridge assembly58in a counter-clockwise direction.

Another preferred embodiment of the parallel linkage assembly505of the mechanism for effectuating the articulation of cartridge assembly58is illustrated inFIGS. 45-49. This assembly includes a looped cable620, which replaces the parallel coupler links534and536discussed hereinabove, for operatively associating the spaced apart proximal and distal crank members516and522, which, in this embodiment, serve primarily as a pair of capstans. A first ball-type fastener622is provided at the leading portion of cable loop620for securing the cable to distal crank member522, and a second ball-type fastener624is provided at the trailing portion of cable loop620for fixing the cable to proximal crank member516. A coupling626is rigidly mounted on the driving leg628of cable loop620for operatively receiving and retaining the distal end of transmission rod560so as to interconnect the actuation assembly510of surgical apparatus500to the linkage assembly505thereof.

Referring toFIG. 47, in use, the cable loop620is manipulated through longitudinal translation of transmission rod560in response to manipulation of barrel cam assembly510(see FIGS.36and38). Thus, proximal translation of transmission rod560, as indicated by arrow “C” inFIG. 48, will cause cable loop620to rotate in a clockwise direction, turning pivot block528in a clockwise direction to articulate the forward housing270of cartridge housing58through an arcuate path (see FIG.38). Similarly, distal translation of transmission rod560, as indicated by arrow “D” inFIG. 49, will cause cable loop620to rotate in a counterclockwise direction, causing distal crank member522to pivot in a counter-clockwise direction. As a result, the forward housing270of cartridge assembly58will be moved arcuately in a counter-clockwise direction (see FIG.36).

Another preferred embodiment of the actuation assembly510is illustrated inFIGS. 50 and 51, and is particularly adapted and configured for progressively articulating cartridge assembly58within an angular sector of rotation. This assembly comprises a sleeve member650disposed about the elongated portion54of surgical apparatus500adjacent the frame portion52thereof. A continuous helical track652is defined about the outer circumference of the distal end portion654of sleeve member650, and a knurl656is formed at the proximal end portion of sleeve member650. An annular knob member658is mounted coaxial with the distal end portion of sleeve member650and is provided with a pair of opposed and staggered follower pins660and662which are configured and positioned to travel within helical track652as knob member658is rotated relative to sleeve member650for effecting the progressive articulation of cartridge assembly58.

A retainer ring664having an annular flange portion668is mounted within an annular groove670defined in knob member658. Retainer ring664is also provided with an engagement port672for receiving the engaging arm580formed at the proximal end of transmission rod560. A pair of diametrically opposed grooves674and676are formed in the interior of retainer ring664for engaging a pair of opposed corresponding keys678and680which extend radially outward from the cover tube182of elongated portion54adjacent sleeve member650. Through this engagement, rotation of transmission rod560will be inhibited as knob member658is rotated to drive transmission rod560in a longitudinal direction for effectuating the progressive articulation of cartridge assembly58. However, when sleeve member650is rotated about the longitudinal axis of elongated portion54, the engagement of the keys678and680within the opposed grooves674and676will effectuate rotation of cartridge assembly58relative to the frame portion52of surgical apparatus500. Finally, a securement ring682is fastened to the distal face684of knob member658by a plurality of threaded fasteners686for maintaining retainer ring664within annular groove670.

Referring toFIG. 52, another preferred embodiment of a surgical instrument in accordance with the subject invention is illustrated and is designated generally by reference numeral700. This instrument is intended to provide the surgeon with a substantially increased range of operability during a surgical procedure. In brief, surgical instrument700comprises a frame or handle assembly702, an elongated body portion704extending from the handle assembly702and defining a longitudinal axis, and a fastener applying assembly706which is pivotably associated with a distal end708of body portion704.

The fastener applying assembly706includes a base portion710which is pivotably mounted to the distal end708of body portion706by means of a main joint pin707(see generally FIG.63). A cartridge assembly712is configured to be mounted within the base portion710and an anvil member715is positioned adjacent the cartridge assembly712against which staples ejected from the cartridge assembly are formed (see generally FIG.58).

Surgical instrument700includes three mechanisms for effectuating distinct movements of the fastener applying assembly706. These mechanisms include a rotation control mechanism for effectuating rotation of the fastener applying assembly706about a longitudinal axis defined by the elongated body portion704. This first mechanism is operated through rotation of a control knob714which is fixed about the proximal end of body portion704(see FIG.52). The second mechanism is an articulation control mechanism for moving the base portion710of the fastener applying assembly706relative to the elongated body portion704within an angular sector of rotation. This second mechanism is operated through rotation of control knob716(see FIG.53). A third mechanism is provided for controlling the independent rotation of the cartridge assembly712together with the anvil member715relative to the base portion710of the fastener applying assembly706(see FIG.54). This third mechanism is operated through rotation of control knob718. These control mechanisms will be described in greater detail hereinbelow.

Referring now toFIGS. 55-57, the handle assembly702of surgical instrument700includes a handle body720for enclosing a pneumatic actuation which is operative to effectuate the ejection of surgical staples from the cartridge assembly712. This pneumatic assembly is similar in many respects to those described hereinabove. However, the pneumatic assembly ofFIGS. 55-57serves to create a power stroke which is directed in a proximal direction rather than a distal direction. In brief, the pneumatic assembly includes a gas supply container722, a piston member724having a piston head727accommodated within a cylinder725and a coiled return spring726. As best seen inFIG. 57, piston head727has a substantially elliptical configuration, as does the cylinder725within which it is accommodated. The elliptical configuration of piston head727and cylinder725provides increased power during a staple driving operation while maintaining substantially the same overall dimensions of the handle assembly702. In a preferred embodiment of the invention wherein surgical instrument700is adapted to apply six rows of staples, each staple row measuring about 60 mm in length, and to simultaneously cut between the two innermost staple rows, the major axis of elliptical piston head727is between about 0.65 and 0.70 inches, and the minor axis is between about 0.45 and 0.50 inches. The corresponding elliptical cylinder725has a major axis of about 0.80 to 0.85 inches and a minor axis of about 0.60 to 0.65 inches. An elliptical O-ring is provided on piston head727to pneumatically seal piston head727to cylinder725. Other cross-sectional configurations are also contemplated and are within the scope of the invention. A flexible conduit723connects the gas supply container722to piston724for the delivery of compressed gas. In use, the delivery of compressed gas from the container722is controlled by a trigger731disposed at the proximal end of handle body720. Operation of trigger731to fire the instrument is substantially identical to that described above with respect to the other embodiments of the invention.

An elongated actuation rod728is associated with piston724and extends operatively therefrom, through the body portion704of surgical instrument700, to the distal end708thereof. The distal end of actuation rod728is mounted to a cartridge adapter730which is illustrated inFIG. 62in conjunction with the removable cartridge assembly712. Adapter730interconnects actuation rod728to a stepped draw bar732. Draw bar732defines a proximal section734, an intermediate stepped section736, and a distal section738. The distal section738of draw bar732extends through the cartridge assembly712, beneath the staple carrying cartridge737disposed therein, to connect with a staple ejecting assembly associated with the cartridge assembly712.

Referring toFIGS. 58 and 59, the staple ejecting assembly includes a cam driver740which serves to drive a plurality of spaced apart cam members, i.e. cam members742. The cam members are disposed within, and translate along, a plurality of tracks defined in the staple containing cartridge737(see generally FIG.18). Cam members742are dimensioned and configured to effect the sequential ejection of a plurality of surgical staples from the staple containing cartridge737as a result of their travel from an initial distal position to a final proximal position. The staple ejecting assembly further comprises a knife blade744mounted upon a shank746which is adapted to translate with and behind cam members742during a stapling operation to divide the stapled tissue. The ejection of staples from the cartridge is accomplished much in the same way as that which has been described hereinabove with respect to previous embodiments of the subject invention. However, as described herein, cam members742translate from a distal to a proximal direction to sequentially drive the staples from the cartridge.

In operation, the sequential ejection of a plurality of surgical staples from the staple containing cartridge737is effectuated by depressing trigger731. Movement of trigger731will cause gas to be released from supply container722which will exert pressure upon the elliptical piston head727, urging piston724in a proximal direction. As piston724translates proximally, return spring726is compressed, and actuation rod728is drawn proximally therewith. As a result, draw bar732is pulled proximally within the elongated portion704of surgical instrument700. The proximal translation of draw bar732causes the cam members742to travel in proximal direction within the tracks which are defined in the staple containing cartridge737. Once the cam bars have completed their proximal-to-distal translation through the staple containing cartridge737, the pressurized cylinder725vents through a plurality of circumferentially disposed apertures747, thereby permitting compressed return spring726to drive piston724distally into its initial pre-fired position. The distal movement of actuation rod728in response to decompression of return spring726causes cartridge adaptor730to return cam members732distally through staple-containing cartridge737. However, knife blade744preferably remains in its proximal-most position by disengaging from the staple firing mechanism, e.g., by becoming lodged in a plastic knife block at the proximal end of the knife blade's travel path through staple containing cartridge737.

Referring toFIGS. 55 and 56, handle assembly702further comprises an actuation lever750for controlling the approximation of the cartridge assembly712and the anvil member715. Actuation lever750is operatively connected to an approximation cable754which extends through the body portion704of surgical instrument700to an approximation link755associated with the fastener applying assembly706. The distal end756of cable754is terminated in a universal ball joint fitting758which is maintained within a cavity760defined within approximation link755. The entryway to cavity760is tapered to accommodate the angular bending of cable754during approximation.

Approximation link755is normally biased into the position shown inFIG. 58so as to maintain the cartridge assembly712and anvil member715in an open position. This may be accomplished by known biasing structure including, for example, a leaf, compression or torsion spring. Approximation link755is pivotably associated with cartridge assembly712through a transverse pivot pin762, and it is associated with the anvil member715through a cam pin764. Cam pin764is dimensioned and configured to cooperate with a cam slot766which is defined within articulator link755. To approximate the cartridge housing712toward the anvil member715to engage tissue therebetween, lever750is moved from the position shown inFIG. 55to that ofFIG. 56, causing approximation cable752to be drawn proximally. As approximation cable752is drawn proximally, link755will rotate about pivot pin762in a clockwise direction, urging cam pin764to move through an arcuate path under the influence of cam slot766, thereby approximating cartridge assembly712and anvil member715.

Turning now toFIGS. 61 and 63, in conjunction withFIG. 53, the mechanism for effectuating the articulated movement of the fastener applying assembly706relative to the elongated portion704of surgical instrument700includes a planetary gear assembly770. Planetary gear assembly770is operatively connected to the base portion710of fastener applying assembly706by means of an offset elongated transmission link772which extends through body portion704. As illustrated inFIG. 61, the planetary gear assembly770is associated with knob716and includes an outer ring gear774, an internal gear776which rotates about a fixed axis in response to the rotation of outer ring gear774, and a worm gear778. Worm gear778extends through the center of the internal gear776and translates longitudinally in response to rotation of internal gear776. Worm gear778is operatively connected to the proximal end of the elongated transmission link772. The distal end of transmission link772is pivotably connected to the base portion710of fastener applying assembly706by means of pivot pin780. Thus, in operation, rotation of knob716in the direction indicated by arrow “A” inFIG. 53will cause corresponding longitudinal translation of offset link722, articulating the fastener applying assembly706within an angular sector of rotation, i.e. within a 45° sector of rotation with respect to the longitudinal axis defined by the elongated body704as indicated by arrow “A′” inFIG. 53to increase the range of operability of the apparatus of the subject invention. Although the surgical instrument700is shown with a base portion articulatable in only a singular radial direction, it is well within the scope of the present invention to provide for a base portion capable of articulation in symmetric radial directions as shown in the preceding embodiments.

Referring now toFIGS. 60,63, and64, in conjunction withFIG. 54, the mechanism for effectuating the independent rotation of the cartridge assembly712together with the anvil member715relative to the base portion710of the fastener applying assembly706includes proximal and distal planetary gear assemblies782and784. The proximal planetary gear assembly782is interconnected to the distal planetary gear assembly784by means of an offset elongated transmission axle786. Proximal planetary gear assembly782is associated with the distalmost control knob718on elongated body portion704and is illustrated in FIG.60. Gear assembly782includes an outer ring gear788which rotates in response to rotation of knob718, and an internal gear790which is configured to rotate about a fixed axis in response to the rotation of outer ring gear788. The proximal end of transmission axle786, which preferably has a hexagonal cross-section, is axially mounted within the internal gear790and is configured to rotate therewith in response to rotation of knob718.

The distal planetary gear assembly784, which is illustrated inFIG. 64, is associated with the base portion710of fastener applying assembly706and includes an outer pinion gear792. Pinion gear792is configured to rotate in response to the rotation of transmission axle786. More particularly, the outer pinion gear792is mounted to transmission axial786by means of a flexible coupling rod794which may be fabricated from a pseudoelastic material such as, for example, TINEL material. Other types of rotational drive structure are also contemplated and are within the scope of the invention. These include, for example, universal joints, reinforced flex cabling, etc. The proximal end of coupling rod794is mounted in the distal end of the transmission axle786, and the distal end thereof is mounted to a fitting796which is operatively associated with outer pinion gear792. The distal planetary gear assembly784further includes an internal ring gear798which is configured to rotate in response to the rotation of pinion gear792.

As best seen inFIG. 63, the proximal end of the cartridge assembly712defines an adapter fitting800, which is dimensioned and configured to mount operatively within the internal ring gear798of the distal planetary gear assembly784so as to effectuate the independent rotation thereof relative to the base portion710of fastener applying assembly706. Thus, in operation, rotation of the distal knob718in the direction indicated by arrow “B” inFIG. 54will cause corresponding rotation of transmission axial786, which, in turn, will rotate the flexible coupling rod794. In response, the outer pinion gear792will rotate, causing the internal ring gear798to rotate along with cartridge assembly712in the direction indicated by arrow “B′” in FIG.54. Furthermore, since the anvil715is mounted adjacent the cartridge housing712it will rotate therewith so as to further increase the range of operability of the surgical apparatus of the subject invention.

It will be understood by those having ordinary skill in the art that various modifications or changes can be made to the various embodiments of the subject invention herein disclosed without departing from the spirit or scope thereof. For example, various sizes of the instrument are contemplated, as are various types of construction materials. Therefore, the above description should not be construed as limiting the invention, but merely as exemplifications of preferred embodiments thereof.

To the extent not already indicated, it will also be understood by those having ordinary skill in the art that any one of the specific embodiments herein described and illustrated may be further modified to incorporate features shown in other of the embodiments.