Feedback and lockout mechanism for surgical instrument

[0001] This application relates to a surgical apparatus, and more particularly, to a mechanism for use with an endoscopic surgical apparatus for sequentially applying a plurality of surgical fasteners to body tissue and optionally incising fastened tissue.

[0002] Surgical devices wherein tissue is first grasped or clamped between opposing jaw structures and then joined by surgical fasteners are well known in the art. In some instruments a knife is provided to cut the tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples but two part polymeric fasteners also can be utilized.

[0003] Instruments for this purpose can include two elongate members which are respectively used to capture or clamp tissue. Typically, one of the members carries a staple cartridge that houses a plurality of staples arranged in at least two lateral rows while the other member has an anvil that defines a surface for forming the staple legs as the staples are driven from the staple cartridge. Generally, the stapling operation is effected by cam bars that travel longitudinally through the staple cartridge, with the cam bars acting upon staple pushers to sequentially eject the staples from the staple cartridge. A knife can travel longitudinally between the staple rows to cut and/or open the stapled tissue between the rows of staples. Such instruments are disclosed, for example, in U.S. Pat. No. 3,079,606 and U.S. Pat. No. 3,490,675.

[0004] A later stapler disclosed in U.S. Pat. No. 3,499,591 applies a double row of staples on each side of the incision. This is accomplished by providing a disposable loading unit in which a cam member moves through an elongate guide path between two sets of staggered staple carrying grooves. Staple drive members are located within the grooves and are positioned in such a manner so as to be contacted by the longitudinally moving cam member to effect ejection of the staples from the staple cartridge of the disposable loading unit. Other examples of such staplers are disclosed in U.S. Pat. Nos. 4,429,695 and 5,065,929.

[0005] Each of the instruments described above were designed for use in conventional surgical procedures wherein surgeons have direct manual access to the operative site. However, in endoscopic or laparoscopic procedures, surgery is performed through a small incision or through a narrow cannula inserted through small entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, endoscopic surgical stapling devices have been developed and are disclosed in, for example, U.S. Pat. No. 5,040,715 (Green, et al.); U.S. Pat. No. 5,307,976 (Olson, et al.); U.S. Pat. No. 5,312,023 (Green, et al.); U.S. Pat. No. 5,318,221 (Green, et al.); U.S. Pat. No. 5,326,013 (Green, et al.); and U.S. Pat. No. 5,332,142 (Robinson, et al.).

[0006] One type of surgical stapling apparatus is configured to operate with disposable loading units (DLUs) that are constructed to support a staple cartridge and knife assembly therein. Once the procedure is completed, the entire DLU is discarded. Such instruments that are designed to accommodate DLUs purport to offer the advantage of a “fresh” knife blade for each firing of the instrument. Examples of such surgical stapling apparatuses and DLUs are disclosed in U.S. Pat. No. 5,865,361 to Milliman et al., the disclosure of which is herein incorporated by reference.

[0007] Some conventional endoscopic surgical cutting and stapling systems incur instances of faulty lockout after the cartridge has been fired, whether partial or complete. Furthermore, in such conventional endoscopic surgical cutting and stapling systems mechanical detection of spent cartridges is inconsistent. Some conventional endoscopic surgical cutting and stapling systems incorporate excessive mechanical and polymeric components, which can be overcome with forces generated in normal deployment of the endoscopic device and thus overcome the lockout mechanism. Therefore, it would be extremely beneficial to provide a surgical cutting and stapling device for use during laparoscopic and/or endoscopic surgical procedures that provides reliable partial or complete spent cartridge lockout functionality. It also would be particularly beneficial if the device could perform multiple tasks, using DLUs of varying size and of varying purpose, such as, for example, to staple, clip, cut and/or articulate and provide an energy activated continuity lockout system and a display device.

[0008] In one embodiment a surgical stapling apparatus comprises a handle assembly including a movable handle. The movable handle is movable through an actuation stroke. An elongate body extends distally from the handle assembly and defines a longitudinal axis. The elongate body has a distal end adapted to releasably engage both articulating and non-articulating disposable loading unit types. An actuation shaft is supported at least in part within the handle assembly and is mounted for longitudinal movement in response to manipulation of the actuation handle. An energy activated firing lockout system prevents operation of the surgical stapling apparatus under a plurality of conditions.

[0015] Preferred embodiments of the presently disclosed endoscopic surgical cutting and stapling apparatus will now be described in detail with reference to the drawings, in which like reference numerals designate identical or corresponding elements in each of the several views.

[0016] In the drawings and in the description that follows, the term “proximal,” as is traditional, will refer to the end of the stapling apparatus which is closest to the operator, while the term “distal” will refer to the end of the apparatus which is furthest from the operator. It will be further appreciated that, for convenience and clarity, spatial terms such as “vertical,” “horizontal,” “up,” “down,” “right,” and “left” are used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and absolute.

[0017] FIGS. 1-4 depict a surgical apparatus 10 for cutting and stapling comprising an energy activated firing lockout system 510 (FIGS. 3-5). The construction and general operation of surgical apparatus 10 is described generally in U.S. Pat. No. 5,865,361, the disclosure of which has been herein incorporated by reference. Thus, the present detailed description will not discuss the various components of surgical apparatus 10 and their operation herein beyond what is necessary to describe the operation of energy activated firing lockout system 510.

[0018] With reference to FIGS. 1-4, in accordance with one embodiment, surgical apparatus 10 for sequentially applying a plurality of fasteners to body tissue and simultaneously incising tissue is provided. Surgical apparatus 10 includes a handle assembly 12 and an elongate body 14. Surgical apparatus 10 is adapted to receive disposable loading units having rows of staples having a linear length of between about 30 mm and about 60 mm. Surgical apparatus 10 also is adapted to receive articulating and non-articulating disposable loading units. In one embodiment, a disposable loading unit or DLU 16 is releasably secured to a distal end of elongate body 14. DLU 16 includes a tool assembly 17 having a cartridge assembly 18 housing a plurality of surgical staples and an anvil assembly 20 movably secured in relation to cartridge assembly 18. DLU 16 is configured to apply linear rows of staples measuring from about 30 mm to about 60 mm in length. DLUs 16 having linear rows of staples of other lengths are also envisioned, e.g., 45 mm. The staples may have a height of about 0.75 mm, 1 mm, 1.5 mm, or 2 mm and may be either bent (curved) or straight.

[0019] In one embodiment, surgical apparatus 10 also includes a reload identification device 536 for sensing the type of DLU 16 positioned within elongate body 14 or DLU 16 portions of surgical apparatus 10. Reload identification device 536 includes a solid state circuit or an integrated circuit with a memory. The memory may be a read-only memory (ROM) comprising at least one programmable or once-writable bit or register. Reload identification device 536 is readable and writable by a computer 538 (FIG. 5) (e.g., controller, processor). Computer 538 is used generally and includes any programmable state machine, hardware, software, memory, and necessary input/output devices. Reload identification device 536 stores status information related to cartridge assembly 18. For example, reload identification device 536 may contain information about whether cartridge assembly 18 has been fired and the type of staples loaded in cartridge assembly 18. The type of staples includes staples having a length of about 30 mm, 45 mm, or 60 mm. Each length type of staple may have a height of about 0.75 mm, 1 mm, 1.5 mm, or 2 mm. The staples may be bent (curved) or straight. In addition to the information of about staple type, reload identification device 536 may contain information associated with cartridge assembly 18 type and whether cartridge assembly 18 has been fired and is partially or completely spent. Reload identification device 536 provides information stored therein to computer 538 upon the application of electrical energy from a direct current (DC) such as battery 530 (FIG. 5), or other DC power source such as a supercapacitor. The information identifying cartridge assembly 18 type and firing status may be displayed on display device 500 for the benefit of the user. The operation of reload identification device 536 within surgical apparatus 10 is described below.

[0020] In one embodiment, elongate body 14 or DLU 16 portions of surgical apparatus 10 comprise a load sensor 537. Load sensor 537 is coupled to display device 500 and computer 538 (e.g., processor). Load sensor 537 measures loads applied at DLU 16, which can be read by computer 538 and displayed by display device 500. Load sensor 537 may be configured to sense and measure force and or torque applied at DLU 16. Load sensor 537 may be located within elongate body 14 to sense and measure force or torque. Load sensor 537 may be located in any suitable portion of surgical apparatus 10 to sense various forces or torques associated with the operation of surgical apparatus 10.

[0021] In one embodiment, surgical apparatus 10 includes a handle assembly 12 having a movable handle and a stationary handle. The movable handle is movable through an actuation stroke to clamp tissue and to effect ejection of staples from the disposable loading unit. An elongate body extends distally from handle assembly 12 and defines a longitudinal axis. An actuation shaft having a toothed rack is operably associated with movable handle assembly 12 by a pawl mechanism. The distal end of the actuation shaft is connected to a control rod having a distal end adapted to operatively engage an axial drive assembly located within a disposable loading unit. In the illustrated embodiment, handle assembly 12 includes a stationary handle member 22, a movable handle member 24, and a barrel portion 26. A rotatable member 28 is preferably mounted on the forward end of barrel portion 26 to facilitate rotation of elongate body 14 with respect to handle assembly 12. Movable handle member 24 comprises a flexible handle portion 508, a firing release portion 504, and a firing switch 506.

[0022] In one embodiment, surgical apparatus 10 also includes an articulation mechanism (not shown) having an articulation lever 30 operatively engaged with a cam member having a stepped camming channel. The articulation mechanism is supported on rotatable member 28 and includes articulation lever 30 pivotably mounted about a pivot member 140, which extends outwardly from rotation member 28 and is preferably formed integrally therewith. The cam member is engaged with a translation member, which includes a pin dimensioned to be received within the stepped camming channel, such that pivotable movement of the lever causes linear movement of the translation member. A first articulation link includes a proximal end adapted to engage the translation member and a distal end adapted to engage a second articulation link positioned within the disposable loading unit. Linear movement of the translation member causes linear movement of the articulation links to cause articulation of a tool assembly 17 of DLU 16. In the illustrated embodiment, articulation lever 30 is also preferably mounted on the forward end of barrel portion 26 adjacent rotatable member 28 to facilitate articulation of tool assembly 17.

[0023] Handle assembly 12 includes housing 36, which is preferably formed from molded housing half-sections 36a and 36b, which forms stationary handle member 22 and barrel portion 26 of handle assembly 12. Movable handle member 24 is pivotably supported between housing half-sections 36a and 36b about pivot pin 38. A biasing member (not shown), which is preferably a torsion spring, biases movable handle 24 away from stationary handle 22. An actuation shaft 46 (FIG. 3) is supported within barrel portion 26 of housing 36 and includes a toothed rack 48. A driving pawl 42 having a rack engagement finger 43 is pivotably mounted to one end of movable handle 24 about a pivot pin 44. A biasing member (not shown), which is also preferably a torsion spring, is positioned to urge engagement finger 43 of driving pawl 42 towards toothed rack 48 of actuation shaft 46. Movable handle 24 is pivotable to move engagement finger 43 of driving pawl 42 into contact with toothed rack 48 of actuation shaft 46 to advance the actuation shaft linearly in the distal direction. The forward end of actuation shaft 46 rotatably receives the proximal end of a control rod 52 such that linear advancement of actuation shaft 46 causes corresponding linear advancement of control rod 52.

[0024] In one embodiment, movable handle member 24 may be coupled to a load sensor 539. Load sensor 539 is coupled to display device 500 and computer 538 (e.g., processor). Load sensor 539 measures loads applied along surgical apparatus 10, which can be read by computer 538 and displayed by display device 500. Load sensor 539 may be configured to sense force and or torque applied at various portions of surgical apparatus 10. In the illustrated embodiment, load sensor 539 is operatively coupled to pivot pin 38 to sense torque applied by movable handle member 24. Load sensor 539 also may be coupled to pivot pin 44 (not shown) to sense force or torque applied by surgical apparatus 10.

[0025] A retraction mechanism 58 which includes a pair of retractor knobs 32 (See FIG. 1) is connected to the proximal end of actuation shaft 46 by a coupling rod 60. Coupling rod 60 includes right and left engagement portions (not shown) for receiving retractor knobs 32 and a central portion (not shown). Retractor knobs 32 are movably positioned along barrel portion 26 to return actuation shaft 46 to a retracted position, as will be described in detail below. Retraction mechanism 58 is dimensioned and configured to translate within a pair of longitudinal slots 34 formed on either side of barrel portion 26. A release plate 64 is operatively associated with actuation shaft 46 and is mounted for movement with respect thereto in response to manipulation of retractor knobs 32. A pair of spaced apart pins 66 extend outwardly from a lateral face of actuation shaft 46 to engage a pair of corresponding angled cam slots 68 formed in release plate 64. Upon rearward movement of retractor knobs 32, pins 66 can release plate 64 downwardly with respect to actuation shaft 46 and with respect to toothed rack 48 such that the bottom portion of release plate 64 extends below toothed rack 48 to disengage engagement finger 43 of driving pawl 42 from toothed rack 48. A transverse slot 70 is formed at the proximal end of release plate 64 to accommodate the central portion of coupling rod 60, and elongate slots 34 are defined in barrel section 26 of handle assembly 12 to accommodate the longitudinal translation of coupling rod 60 as retractor knobs 32 are pulled rearwardly to retract actuation shaft 46 and thus retract control rod 52 rearwardly. Actuation shaft 46 is biased proximally by a spring (not shown).

[0026] In one embodiment, surgical apparatus 10 preferably includes a display device 500. Display device 500 provides feedback to the user as to the position of the knife, the firing status of cartridge assembly 18, and the type of staples contained in cartridge assembly 18. The feedback may be in the form of numeric, alphanumeric, or graphical elements displayed on the display device. For example, to provide visual feedback of the position of the knife, a longitudinal that is correlated to the longitudinal displacement of the knife may be displayed. Display device 500 also may provide feedback as to the status of the DLU 16 and the lockout status of surgical apparatus 10. In the illustrated embodiment, display device 500 is located on either side of barrel portion 26. An On/Off switch 502 is located on barrel portion 26 to electrically activate and deactivate the electrical component portions of surgical apparatus 10. On/Off switch 502 connects battery 530 to various electrical components throughout surgical apparatus 10 including display device 500, solenoid 512, and unclamp switch 528, for example.

[0027] In one embodiment, surgical apparatus 10 preferably includes an energy activated firing lockout system 510. Energy activated firing lockout system 510 is active in a non-energized state to provide lockout operation in the event of system energy failure. Energy activated firing lockout system 510 prevents operation of surgical apparatus 10 under various conditions, such as, for example, if an empty (e.g., spent) staple cartridge is present; if no staple cartridge is present; if a partially spent staple cartridge is present after knife retraction; if a partially spent staple cartridge is present after unclamping the surgical stapling apparatus; and if a partially spent staple cartridge is present after complete cycling of the surgical stapling apparatus.

[0028] FIG. 3 illustrates the interconnection of elongate body 14 and handle assembly 12. Housing 36 includes an annular channel 117 configured to receive an annular rib 118 formed on the proximal end of rotation member 28, which is preferably formed from molded half-sections. Annular channel 117 and rib 118 permit relative rotation between rotation member 28 and housing 36. Rotation of rotation knob 28 with respect to handle assembly 12 thus results in corresponding rotation of elongate body 14 with respect to handle assembly 12.

[0029] Referring to FIGS. 3 and 4, energy activated firing lockout system 510 includes a solenoid 512 and a pivotable locking member 514. Solenoid 512 is energized by battery 530. Pivotable locking member 514 is pivotable about pivot pin 516 and includes a locking surface 518 configured to lock into notch 522. A biasing member 520, which is preferably a compression coil spring, biases pivotable locking member 514 in a locked position (as shown). Locking surface 518 is fixedly coupled to pivotable locking member 514 by fastener 526. In a de-energized state (shown in solid line) a plunger 524 portion of solenoid 512 is sufficiently retracted to allow locking surface 518 to withdraw into notch 522 to prevent the horizontal translation of actuation shaft 46. When plunger 524 is activated by energizing solenoid 512 plunger 524 drives pivotable locking member 514 downward to an unlocked position (shown in phantom) to pivot pivotable locking member 514 in a downward direction (also shown in phantom) and release locking surface 518 from notch 522 to enable horizontal translation of actuation shaft 46.

[0030] Firing lockout system 510 must be unlocked to advance actuation shaft 46 distally. To unlock firing lockout system 510 firing release portion 504 of movable handle 24 is moved in the direction indicated by arrow “B” into engagement with firing switch 506 to actuate solenoid 512. When actuated, solenoid 512 drives plunger 524 in a downward direction to release locking surface 518 from notch 522. Once locking surface 518 is released from notch 522, actuation shaft 46 may be advanced distally by pivoting movable handle 24 about pivot pin 38 in the direction indicted by arrow “A.” Each stroke advances actuation shaft 46 a predetermined distance (e.g., approximately 15 mm). With each pivot stroke of movable handle 24 rack engagement finger 43 of driving pawl 42 drives toothed rack 48 and actuation shaft 46 distally a predetermined distance. Further distal advancement of actuation shaft 46 is permitted by repeatedly pivoting movable handle 24 about pivot pin 38. Actuation shaft 46 may be returned to a retracted proximal position by pulling retractor knobs 34 proximally, as discussed above. Pulling retractor knobs 34 proximally all the way enables a proximal portion of actuation shaft 46 to contact and actuate unclamp switch 528 to unclamp anvil assembly 20.

[0031] A position sensor is used to determine the longitudinal location of actuation shaft 46. In one embodiment, the position sensor includes an encoder 532 and an induction coil 534. Encoder 532 is fixedly attached to actuation shaft 46 and moves longitudinally therewith. Encoder 532 provides an electrical signal (e.g., analog or digital) that corresponds to the longitudinal position of actuation shaft 46, and hence control rod 52. Induction coil 534 is fixedly mounted to an interior portion of housing 36. Induction coil 534 is located through an aperture formed in encoder 532. The operation of the position sensor is discussed below with reference to FIG. 5.

[0032] FIG. 5 illustrates one embodiment of an energy activated electrical feedback and firing lockout system 550. The energy activated electrical feedback and firing lockout system 550 is operated by battery 530, which acts as a source of electrical energy for switches 506, 528, position sensor encoder 532, induction coil 534, reload identification device 536, computer 538, and display device 500. On/Off switch 502 is used to apply and remove power from battery 530 to the various electrical components. In operation, computer 538 monitors the state of firing switch 506, unclamp switch 528, and the actuation sequence of movable handle member 24.

[0033] As previously discussed, encoder 532 and actuation shaft 46 translate longitudinally, induction coil 534 remains fixed. The electrical signal may be calibrated to correspond to the position of actuation shaft 46 from a first minimum displacement position (fully retracted) to a second maximum displacement position (fully extended). In one embodiment, encoder 532 may be a linear encoder is a sensor, transducer or read-head paired with a scale that encodes position of actuation shaft 46. The sensor reads the scale in order to convert the encoded position into an analog or digital signal, which can then be decoded into position by a digital readout (DRO). Linear encoder technologies include capacitive, inductive, eddy current, magnetic, and optical. Optical technologies include shadow, self imaging, and interferometric. The decoded output of encoder 532 is provided to display device 500, which may include a liquid crystal display (LCD) or similar display element. The decoded output of encoder 532 is indicative of a longitudinal position of actuation shaft 46. Display device 500 displays the encoded output of encoder 532 to provide feedback to the user of the location of actuation shaft 46 and/or control rod 52 along its longitudinal length from the minimum displacement (fully retracted) to the maximum displacement (fully extended). For example, the displacement may be about 0-30 mm for a surgical apparatus 10 with disposable loading units having linear rows of staples of about 30 mm in length, and the displacement may be about 0-60 mm for a surgical apparatus 10 with disposable loading units having linear rows of staples of about 60 mm in length. The read out of display 500 may be numeric, alphanumeric, graphical, or a cumulative bar suitable to indicate the position of actuation shaft 46 along the stroke length (e.g., about 0-30 mm or about 0-60 mm) from minimum displacement (fully retracted) to the maximum displacement (fully extended).

[0034] Sequence of Operation

[0035] With reference now to FIGS. 1-5, the present description of the sequence of operation will not discuss the various components of cutting and surgical apparatus 10 and their operation herein beyond what is necessary to describe the operation of energy activated firing lockout system 510. To use surgical apparatus 10, a disposable loading unit such as DLU 16 is first secured to the distal end of elongate body 14. As discussed above, surgical apparatus 10 can be used with articulating and non-articulating disposable loading units having linear rows of staples between about 30 mm and about 60 mm in various heights (e.g., 0.75 mm, 1 mm, 1.5 mm, or 2 mm) and shapes (e.g., bent/curved, straight). To secure DLU 16 to elongate body 14, the distal end of control rod 52 is inserted into an insertion tip (not shown) of DLU 16, and the insertion tip is slid longitudinally into the distal end of elongate body 14.

[0036] Electrical power from battery 530 is applied to surgical apparatus 10 by turning On/Off switch 502 to the “on” position. Upon the application of electrical energy from battery 530, reload identification device 536 senses the presence of cartridge assembly 18. Computer 538 reads the status of cartridge assembly 18 from reload identification device 536 indicating various states of cartridge assembly 18. Computer 538 enables or disables operation of firing lockout system 510 based on the status of cartridge assembly 18 provided by reload identification device 536. If cartridge assembly 18 is present and fully loaded with staples, computer 538 enables normal operation of surgical apparatus 10. Thus, electrical lockout system 510 may be unlocked by activating firing switch 506 and energizing solenoid 512. Computer 538 prevents solenoid 512 from being energized and keeps electrical lockout system 510 is a locked state, disabling operation of surgical apparatus 10 from use even if firing switch 506 is activated in the following situations: if cartridge assembly 18 is not present; if cartridge assembly 18 is present, but is spent (e.g., without staples); if a partially spent cartridge assembly 18 is present after knife retraction; if a partially spent cartridge assembly 18 is present after unclamping surgical apparatus 10; and if a partially spent cartridge assembly 18 is present after complete cycling of the surgical apparatus 10.

[0037] With DLU 16 attached to stapling instrument 10, tool assembly 17 can be positioned about tissue by first opening anvil assembly 20 and receiving and clamping tissue between anvil assembly 20 and cartridge assembly 18. Anvil assembly 20 can be opened by actuating unclamp switch 528 by retracting actuation shaft 46 using retractor knobs 32. Anvil assembly 20 can be closed by actuating firing switch 506. This may be accomplished by moving movable handle member 24 in the direction indicated by arrow “A” one stroke and actuating firing switch 506. Moving movable handle member 24 in the direction indicated by arrow “A” one stroke moves driving pawl 42 and advances actuation shaft 46 and control rod 52 distally. It is noted that one complete stroke of movable handle 24 advances actuation shaft 46 approximately 15 mm which is sufficient to clamp tissue during the first stroke of movable handle 24 but is not sufficient to fire staples.

[0038] During the first (clamping) stroke of movable handle 24, slide plate 102 prevents locking pawl 54 from engaging toothed rack 48. Upon release of movable handle 24, drive pawl 42 moves over rack 48 as handle 24 is returned to a position spaced from stationary handle 22 by a torsion spring (not shown). In this position, driving pawl 42 is urged into engagement with toothed rack 48 to retain actuation shaft 46 in its longitudinal fixed position.

[0039] To fire staples during a second and subsequent strokes, movable handle 24 is repeatedly actuated, i.e., moved through consecutive strokes. As discussed above, surgical apparatus 10 is capable of receiving DLUs 16 having a variety of linear rows of staples. Since each stroke of movable handle 24 preferably advances actuation shaft 46 approximately 15 mm, and one stroke is required to clamp tissue, movable handle 24 must be actuated (n+1) strokes to fire staples, where n is the length of the linear rows of staples in the disposable loading unit attached to cutting and surgical apparatus 10 divided by approximately 15 mm. For example, n=1 for a 15 mm cartridge; n=3 for a 45 mm cartridge; and n=4 for a 60 mm cartridge.

[0040] Prior to enabling firing staples, firing lockout system 510 must be actuated to move locking surface 518 from a blocking position to a non-blocking position. This is accomplished by squeezing firing release portion 504 of movable handle 24 in the direction indicated by arrow “B” into engagement with firing switch 506 to energize solenoid 512. When solenoid 512 is energized, plunger 524 drives pivotable locking member 514 downward to release locking surface 518 from notch 522 and thus enables horizontal translation of actuation shaft 46. Thereafter, movable handle 24 may be actuated an appropriate number of strokes to advance actuation shaft 46, and thus control rod 52, distally in the direction indicated by arrow “C” to advance the actuation sled (not shown) through the entire length of cartridge assembly 18 to effect ejection of staples.

[0041] In order to insert DLU 16 and elongate body 14 of surgical apparatus 10 through the narrow cannula of the trocar, anvil assembly 20 must initially be closed. Anvil assembly 20 is closed by engaging firing release portion 504 and actuating firing switch 506 once to unlock electrical lockout system 510 (e.g., energizing solenoid 512). With electrical lockout system 510 in the unlocked state, flexible handle 24 can be moved in the direction indicated by arrow “A” one stroke to advance actuation shaft 46 distally to close anvil assembly 20. Once flexible handle 24 is released, electrical lockout system 510 is once again locked. With anvil assembly 20 closed, DLU 16 and elongate body 14 of surgical apparatus 10 can be inserted through the narrow cannula of the trocar to locate tool assembly 17 at the surgical site. Anvil assembly 20 must be opened in order to clamp tissue between anvil assembly 20 and cartridge assembly 18. Anvil assembly 20 may be opened by retracting actuation shaft 46 proximally with retractor knobs 32 until unclamp switch 528 is actuated. When actuation shaft 46 engages unclamp switch 528, computer 538 senses contact closure of unclamp switch 528 and energizes solenoid 512 to unlock electrical lockout system 510. Movable handle member 24 can now be moved in the direction indicated by arrow “A” one stroke to advance actuation shaft 46 distally to close anvil assembly 20 and clamp tissue between anvil assembly 20 and cartridge assembly 18. To fire cartridge assembly 18, the user engages firing release portion 504 and actuates firing switch 506 to unlock electrical lockout system 510 and enable actuation shaft 46 to advance distally by repeatedly actuating flexible handle 24 a suitable number of strokes until the entire cartridge assembly 18 is spent. Once cartridge assembly 18 is spent, the one time programmable memory register in reload identification device 536 is programmed to indicate that cartridge assembly is spent. Thus, any further firings of surgical instrument 10 are prevented by computer 538 because reload identification device 536 because cartridge assembly 18 is spent.

[0042] To retract actuation shaft 46 and thus control rod 52 at the end of the firing stroke, e.g., after firing the staples, retractor knobs 32 are pulled proximally causing pins 66 to move release plate 64 in the direction indicated by arrow “D” over teeth 48 to disengage drive pawl 42 from engagement with teeth 48. When fully retracted, actuation shaft 46 actuates unclamp switch 528 to open anvil assembly 20. Tool assembly 17 can now be removed from the surgical site. Moveable handle member 24 is actuated in the direction indicated by arrow “A” one stroke to close anvil assembly 20 such that tool assembly 17, elongate body 14, and DLU 16 may be retracted through the narrow cannula of the trocar.

[0043] The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the devices can be reconditioned for reuse after at least one use. Reconditioning can include any combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of the particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those skilled in the art will appreciate that reconditioning of a device can utilize a variety of techniques for disassembly, cleaning/replacement, and reassembly. Use of such techniques, and the resulting reconditioned device, are all within the scope of the present application.

[0044] Preferably, the various embodiments described herein will be processed before surgery. First, a new or used instrument is obtained and if necessary cleaned. The device can then be sterilized. This can be done by any number of ways known to those skilled in the art including beta or gamma radiation, ethylene oxide, steam. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK® bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or high-energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility.

[0045] It will be understood that various modifications may be made to the embodiments disclosed herein. For example, the stapling apparatus need not apply staples but rather may apply two part fasteners as is known in the art. Further, the length of the linear row of staples or fasteners may be modified to meet the requirements of a particular surgical procedure. Thus, the length of a single stroke of the actuation shaft and/or the length of the linear row of staples and/or fasteners within a disposable loading unit may be varied accordingly. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended thereto.