Articulation and firing force mechanisms

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 60/985,663 filed Nov. 6, 2007, the entire disclosure of which is incorporated by reference herein.

[0002] 1. Technical field

[0003] The present disclosure relates to firing force mechanisms for use in a surgical instrument. More particularly, the present disclosure relates to firing force mechanisms capable of transmitting a firing or driving force around an angle within a surgical stapling instrument.

[0004] 2. Background of Related Art

[0005] Various surgical instruments are known in the art for performing operations within a body cavity. Certain of these instruments are configured to pass through an access opening in the body of the patient. A handle portion of the instrument remains outside the body while an elongate portion of the instrument passes through the port and into the body cavity. When these types of devices are utilized, it is often difficult to orient the distal end of the elongate portion within body by manipulation of the handle portion of the instrument from outside of the body.

[0006] Unique instruments have been developed which allow the elongate portion of the instrument entering the body to bend or move within the body independent of the position of the handle portion of the instrument outside the body. These “articulating” surgical instruments employ various mechanisms to cause the elongate portion to bend or be reoriented within the body.

[0007] While it is relatively easy for the elongate portion of instrument to be bent or reoriented within the body, the ability to transmit an actuation or driving force around the bend to an end effector associated with the elongate portion poses difficulties. These difficulties include loss of force due to bowing or flexing of the drive elements as they pass around the bend in the elongate portion, etc.

[0008] There is provided a surgical instrument including a handle having an elongate tubular member extending distally from the handle. The elongate tubular member has a proximal portion, a distal portion and an articulation section positioned between the distal and proximal portions. The articulation section allows the distal portion to move relative to the proximal section.

[0009] A drive force mechanism is provided in the surgical instrument and includes a drive element positioned in the proximal portion, a transfer bar positioned in the distal portion and a transfer device positioned in the articulation section. The transfer device receives a driving force from the drive element and reorients the driving force around the articulation section and toward the transfer bar. The transfer device is rotatably mounted in the articulation section.

[0010] The transfer device is rotatably mounted in the articulation section. In one embodiment, the drive element is a gear rotatably mounted at a point of articulation. The drive element includes a rack engagable with the gear so as to rotate the gear in response to longitudinal motion of the rack. The transfer bar includes a rack engagable with the gear such that rotation of the gear moves the transfer bar longitudinally within the distal portion.

[0011] In an alternative embodiment the transfer device includes at least one wheel rotatably mounted in the articulation section. The drive element is a flexible cable which passes around the at least one wheel. The drive mechanism includes a toggle rotatably mounted in the distal portion, a first end of the toggle being connected to the transfer bar. A second end of the toggle is connected to the cable. The cable has an upper section and a lower section, the upper section being connected to the first end of the toggle and the lower section being connected to the second end of the toggle.

[0012] The surgical instrument further includes an actuator positioned in the distal portion to operate an end effector associated with the surgical instrument. The transfer bar is engagable with the actuator and includes a drive tooth engagable with the actuator.

[0013] In a specific embodiment, the drive tooth is releasably engagable with the actuator. The actuator includes a plurality of abutments and the drive tooth includes a drive face engagble within the abutments. The drive tooth also includes a proximal sloped face, the proximal sloped face is engagable with the abutments to disengage the drive tooth from the abutments.

[0029] Embodiments of the presently disclosed driving force mechanisms for use in surgical instruments will now be described in detail with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views. As is common in the art, the term “proximal” refers to that part or component closer to the user or operator, i.e. user, surgeon or physician, while the term “distal” refers to that part or component further away from the user.

[0030] FIG. 1 illustrates a surgical stapler 10 incorporating one embodiment of a driving force mechanism. Surgical stapler 10 generally includes a handle 12 and a distal end portion 14 extending distally from handle 12. Distal end portion 14 is configured for endoscopic use and includes an elongate tubular member 16 extending from a distal end 18 of handle 12. A jaw assembly 20 is mounted on a distal end 22 of elongate tubular member 16 and includes a staple cartridge 24 and an anvil 26. Anvil 26 is mounted for movement between an open position spaced apart from staple cartridge to a closed position substantially adjacent staple cartridge 24. A trigger 28 is provided on handle 12 to actuate jaw assembly 20.

[0031] Surgical stapler 10 is of the type of surgical instruments that are capable of bending or articulating about an articulation section 30 in elongate tubular member 16. Articulation section 30 is located about midway along elongate tubular member 16 separating elongate tubular member 16 into a distal portion 32 and a proximal portion 34. Elongate tubular member 16 bends about an axis “A” of articulation section 30 through an angle α. An articulation actuator 36 is provided on handle 12 to move distal portion 32 relative to proximal portion 34 about axis A (shown in FIGS. 1, 2). Articulation actuator 36 moves articulators 40 and 42 which extend from articulation actuator 36 to articulation section 30. (See FIG. 5) While not specifically shown, various mechanisms are known in the art which are capable of effecting angular movement of distal portion 32 of elongate tubular member 16 relative to proximal portion 34 of elongate tubular member 16 about axis A and through angle α. For example, linkages, flexible bands, gears, etc. In a particular embodiment angle α can be between about 0° to about 90° or more from the longitudinal axis of the proximal portion 34.

[0032] In order to properly orient jaw assembly 20 relative to tissue, surgical stapler 10 includes a rotation knob 44 rotatably mounted on handle 12. Elongate tubular member 16 is mounted in a nose cone portion 46 of rotation knob 44 and a knurled portion 48 is provided on rotation knob 44 to facilitate rotation of distal end portion 14 relative to handle 12.

[0033] Referring to FIG. 2, a driver 50 is mounted for longitudinal movement within handle 12. A pair of guide rails 52 and 54 are provided in handle to support driver 50. As noted above, trigger 28 is provided to actuate jaw assembly 20. Trigger 28 is pivotally mounted on a pivot post 56 formed in handle 20. An upper end 58 of trigger 28 is connected to driver 50 by a pivot pin 60. Movement of trigger 28 translates driver 50 within handle 12 to actuate jaw assembly 20. A return spring 62 is positioned over pivot post 56 and is engagable at a first end 64 with a projection 66 formed in handle 12. A second end 68 of guide spring 64 engages trigger 28 to bias trigger 28 to an open or unfired position.

[0034] As noted above, surgical stapler 10 includes a drive force mechanism in order to transfer an actuation force from trigger 28 to jaw assembly 20. The drive force mechanism includes a drive bar 70 provided within proximal portion 34 of elongate tubular member 16. Drive bar 70 is connected at its proximal end 72 to a rotation collar 74 rotatably mounted in handle 12. Rotation collar 74 is connected to a distal end 76 of driver 50. Rotation collar 74 is provided to allow drive rod 70, as well as other driving force mechanism components, to rotate as distal end portion 14 is rotated through manipulation of rotation knob 44.

[0035] Referring now to FIG. 3, drive rod 70 extends through proximal portion 34 to articulation section 30. A distal end 78 of drive rod 70 includes a first rack 80 to facilitate transfer of a driving force around and through articulation section 30. Drive rod 70 is routed through a guide tube 82 mounted within proximal portion 34 of elongate tubular member 16 to separate driving mechanism components from articulation components. In order to transfer a driving force through articulation section 30, a transfer device, such as transfer gear 84, is rotatably mounted within articulation section 30 on a center spindle 86. Center spindle 86 is mounted within articulation section 30 along axis A. Transfer gear 84 is engagable with drive rod 70 in a manner discussed hereinbelow. A transfer bar 88 is provided within distal portion 32 of elongate tubular member 16 and is provided to transmit forces received from drive rod 70 to jaw assembly 20. Transfer bar 88 includes a second rack 90, at a proximal end 92 thereof, which is engagable with transfer gear 84. A distal end 94 of transfer bar 88 terminates in a drive tooth 96.

[0036] Referring to FIG. 4, first rack 80 includes a plurality of first teeth 98 which are engagable with gear teeth 100 formed on transfer gear 84. Likewise, second rack 90 includes a plurality of teeth 102 also engagable with gear teeth 100 on transfer gear 84. Thus, as drive rod 70 moves longitudinally, first rack 80 rotates transfer gear 84 which in turn drives transfer bar 88 longitudinally within distal portion 32.

[0037] Referring back to FIG. 3, an actuator 104 is movably mounted within distal portion 32. A distal end 106 of actuator 104 includes a crossbar 108 which is engagable with an angled edge of anvil 26 to move anvil 26 between the open and closed positions. While not specifically shown, a knife is also associated with distal end 106 of actuator 104 to sever tissue captured between anvil 26 and staple cartridge 24. Anvil 26 includes a longitudinal slot 112 to allow passage of the knife through jaw assembly 20.

[0038] In order to receive the driving force from transfer bar 88, a proximal end 114 of actuator 104 is provided with a series of abutments 116 engagable with drive tooth 96 at distal end 94 of transfer bar 88. (See FIGS. 3 and 7) Drive tooth 96 repeatedly engages subsequent abutments 116 to incrementally advance actuator 104 within distal portion 32 and thus actuate jaw assembly 20. Actuator 104 is supported for longitudinal motion within distal portion 32 by a pair of guide channels 118 and 120. The abutments 116 may be formed as surfaces defining windows in the actuator 104, notches, pins or teeth.

[0039] The use of the disclosed driving force mechanism of surgical stapler 10 to transmit a driving force around a bend in surgical stapler will now be described. Referring initially to FIGS. 2 and 3, surgical stapler 10 is in an initial position with spring 62 biasing trigger 28 to the open or unfired position. Upper end 58 of trigger 28 places driver 50, and thus drive bar 70, in a proximal position within handle 12 (FIG. 2). As shown in FIG. 3, distal portion 32 of elongate tubular member 16 is in longitudinal alignment with proximal portion 34 and anvil 26 is in the open position spaced apart from staple cartridge 24. Transfer bar 88 and actuator 104 are also in proximal positions within distal portion 32.

[0040] Referring now to FIGS. 1 and 5, upon actuation of articulation actuator 36 (FIG. 1), articulators 40 and 42 are activated to cause elongate tubular member 16 to bend at axis A in articulation section 30 thereby positioning distal portion 32 of elongate tubular member 16 at an angle of approximately 90° relative to proximal portion 34 (FIG. 5). As noted above, various mechanisms and methods are well known in the art to accomplish the bending or articulation at articulation section 30. Jaw assembly 16 is initially positioned about a tissue section “T” to be operated on.

[0041] Referring to FIGS. 1 and 6, trigger 28 is actuated or squeezed proximally causing upper end 58 to drive driver 50 distally within handle 12. As driver 50 moves distally it moves drive bar 70 distally within proximal portion 34 of elongate tubular member 16. As best shown in FIG. 6, distal movement of drive bar 70 rotates transfer gear 84 clockwise about axis A and in the direction of arrow B. Specifically, first teeth 98 of drive bar 70 engages and rotates gear teeth 100 of transfer gear 84. Transfer gear 84 receives the driving force from drive bar 70 and transfers or “redirects” the force through angle α, here 90°, to transfer bar 88. Specifically, gear teeth 100 engage second teeth 102 in second rack 90 forcing transfer bar distally within distal portion 32 of elongate tubular member 16. Thus, the combination of drive bar 70 including first rack 80, transfer gear 84 and transfer bar 88 including second rack 90 form a drive force transfer or “redirecting” mechanism allowing a drive force to be transmitted through an angle formed in a portion of surgical stapler 10. As noted above, drive force mechanisms disclosed herein are equally applicable to other surgical instruments, such as, for example, graspers, cutters, clip appliers, etc. Further, the disclosed drive force mechanisms are equally applicable in other surgical instruments having articulation sections located at other positions on the surgical instrument, for example, at the juncture of a handle and elongate tubular member, adjacent an end effector, etc.

[0042] Referring to FIG. 7, as noted above, drive tooth 96 on transfer bar 88 engages sequential abutments 116 in ratchet or incremental fashion to move actuator 104 distally within distal portion 32 thereby actuating jaw assembly 20. In some cases it may be necessary to provide multiple activations of trigger 28 to fully actuate jaw assembly 20. For each activation of trigger 28, transfer bar 88 and specifically drive tooth 96 moves through a stroke length d1. Drive tooth has a distal drive face 122 to engage abutments 116. In order for transfer bar to pass through a return stroke, drive tooth 96 includes a proximal sloped face 124 which allows drive tooth 96 to disconnect from or “slip of” or abutments 116. Further activation of trigger 28 causes distal drive face 122 of drive tooth 96 to engage subsequent abutments 116. Guide rails 125 and 128 are provided within distal portion 32 to allow distal end 94 of transfer bar 88 to move laterally away from abutments 116, as well as guide transfer bar 88 in its longitudinal motion within distal portion 32.

[0043] Referring to FIGS. 6 and 8, upon full actuation, cross bar 108 of actuator 104 engages angled edge 110 on anvil 26 moving anvil 26 to the closed position relative to staple cartridge 24.

[0044] Referring now to FIG. 9, upon further actuation of surgical stapler 10, a staple bar 130 associated with actuator 104 is moved distally through staple cartridge 24 as actuator 104 moves distally through slot 112 in anvil 26. Staple bar 130 engages pushers 132 positioned within staple pockets 134 in staple cartridge 24. Pushers 132 drive staples 136, also positioned within staple pockets 134, toward anvil 26 such that pointed ends 138, 140 are driven through tissue T and into staple clinching pockets 142 in anvil 26 to thereby staple tissue section T. As noted above, a knife associated with actuator 104 moves distally with cross bar 108 to sever tissue T between the staple lines formed by staples 136.

[0045] Referring now to FIGS. 10-14, there is disclosed another embodiment of a drive force mechanism for use in surgical instruments such as surgical stapler 10. With initial reference to FIG. 10, surgical stapler 10 is as described hereinabove. However, in place of drive bars, racks and gears, the disclosed alternative embodiment includes a cable, wheel and/or pulley system to transfer a driving force from trigger 28 around and through articulation section 30 and to jaw assembly 20. Specifically, a wheel 150 is rotatably mounted on a pivot 152 in handle 12. Upper end 58 is connected to drive wheel 150 at pivot pin 60 so as to rotate drive wheel 150 in response to activation of trigger 28. A drive cable 154 passes around wheel 150 and extends through proximal portion 34 of elongate tubular member 16 and through articulation section 30 to distal portion 32 of elongate tubular member 16. Drive cable 154 is formed from a flexible material so as to pass around wheel 150. Drive cable 154 includes an upper section 156 and a lower section 158. As trigger 28 is activated, upper end 58 of trigger 12 rotates wheel 150 clockwise in handle 12 to advance upper section 156 distally and draw lower section 158 proximally within elongate tubular member 16. A collar 160 is provided within handle 12 and allows drive cable 154 to rotate as elongate tubular member 16 rotates in the manner described hereinabove.

[0046] Referring to FIG. 11, in order to pass the driving forces from drive cable 154 to actuator 104, a lever 162 is provided within distal portion 32 and pivotally mounted at a pivot point 166 on a centerpost 164. A distal end 168 of upper section 156 of drive cable 154 is connected to a first end 170 of lever 162 and a distal end 172 of lower section 158 is connected to a second end 174 of lever 162.

[0047] As noted above, the disclosed drive force mechanisms incorporate transfer devices positioned within articulation section 30 of surgical stapler 10 to transfer and redirect a driving force passing though elongate tubular member 16 as elongate tubular member 16 is bent through an angle α. In this embodiment, the transfer device is in the form of a pair of wheels, including an upper wheel 176 and a lower wheel 178, rotatably mounted on a spindle 180 positioned within articulation section 30. Spindle 180 is located on axis A of surgical stapler 10.

[0048] A transfer bar 182 is positioned within distal portion 32 to transfer forces between lever 162 and actuator 104. A proximal end 184 is affixed to first end 178 of lever 162 and a distal end 186 of transfer bar 182 is attached to a drive tooth 188 which functions substantially identically to drive tooth 96, described hereinabove, to engage abutments 116 and advance actuator 104 within distal portion 32.

[0049] Referring now to FIGS. 10-14, and initially with reference to FIGS. 10 and 11, in use, trigger 28 is in the unfired position with wheel 150 at rest. Proximal portion 34 of elongate tubular member 16 is in longitudinal alignment with articulation section 30 and distal portion 32. Anvil 26 is in the open position spaced apart from staple cartridge 24.

[0050] Referring to FIGS. 10 and 12, as discussed hereinabove, articulation actuator 36 is activated to bend elongate tubular member 16 at articulation section 30 and position jaw assembly 16 relative to a tissue section “T” such that anvil 26 and staple cartridge 24 are positioned about a tissue section T. Trigger 28 is activated to rotate wheel 150 clockwise drawing lower section 158 of drive cable 154 proximally and forcing or allowing upper section 156 to move distally.

[0051] As shown in FIG. 12, upper section 156 of drive cable 154 passes around upper wheel 176 in articulation section 30 while lower section 158 passes around lower wheel 178. As lower section 158 is drawn proximally, lower section 158 pulls on second end 174 of lever 162, rotating lever 162 clockwise and driving first end 170 of lever 162 distally. Distal movement of first end 170 drives transfer bar 182 distally causing drive tooth 188 to engage a abutment 116 and advance actuator 104 distally within distal portion 32 of elongate tubular member 16.

[0052] Referring to FIG. 13, and as discussed hereinabove, distal movement of actuator 104 forces crossbar 108 against angled edge 110 of anvil 26 to move anvil 26 to the closed position relative to staple cartridge 24. Subsequent activations of trigger 28 will result in further actuation of surgical stapler 10 to staple tissue T in the manner described hereinabove.

[0053] Referring to FIG. 14, drive tooth 188 also passes through stroke d1 to incrementally advance actuator 104 by successive engagements with abutments 116. Drive tooth 188 includes a distal drive face 190 for engagement with abutments and a proximal sloped face 192 which allows drive tooth 188 to disengage from a abutment 116 on a return stroke of drive tooth 188 and reengage a subsequent abutment 116.

[0054] In this manner the above described drive force mechanisms allow a driving force to be transmitted from a handle of the surgical instrument around an articulated section in the surgical instrument and, ultimately, transmitted to a jaw assembly of the surgical instrument.

[0055] It will be understood that various modifications may be made to the embodiments disclosed herein. For example, other activation mechanisms may be provided, such as, for example, gas powered, etc. Further, the disclosed driving force mechanisms are equally suited for use in surgical instruments having articulation point at or close to associated end effectors. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.