SURGICAL INSTRUMENT

Abstract: A detachable medical instrument includes an actuator (230), and a distal assembly (220). A distal coupler (241) of the actuator (230), and a proximal coupler of the distal assembly (220) detachably engage. The couplers (254, 254a) are configured to be non-fixedly engaged together when one of the couplers (254, 254a) is in a first orientation. The couplers (254, 254a) are configured to be fixedly engaged together when the one of the couplers (254, 254a) is moved from its first orientation to a second orientation. A method of assembling a medical instrument includes positioning the distal coupler (241) in a first orientation with respect to the proximal coupler such that the couplers are non-fixedly engaged together; and moving one of the couplers relative to the other to a second orientation to fixedly engage the actuator to the distal assembly (220).

Description: SURGICAL INSTRUMENT Background of the Invention The invention relates to a surgical instrument, particularly to a surgical instrument for use during arthroscopic surgery. Arthroscopic instruments generally have an actuating assembly attached to a handle with an end effector having at least one movable implement located at the distal end of the actuating assembly. Arthroscopic instruments are known which have an actuating assembly that is removable from a handle. It is also known to make arthroscopic instruments having an end effector that is replaceable as a unit. Summary of the Invention The invention permits individual replacement of the implements of the end effector as opposed to replacement of the end effector as a unit. In one general aspect of the invention, a medical instrument includes an elongated shaft, a plurality of implements mounted to the shaft, and an actuator coupled to produce relative movement between the implements. At least one of the implements is detachable from the shaft and the actuator and from another one of the implements. Preferred embodiments may include one or more of the following features. The actuator includes a distal portion with an inclined slot. One of the implements is detachably coupled to the slot such that movement of the actuator causes the relative movement between the implements. The distal portion of the actuator includes a plurality of inclined slots. Each of the implements is detachably coupled to one of the slots. The implements are scissors mounted to pivot open and closed. The shaft includes spring arms detachably coupled to the implements. The actuator includes a proximal portion for snap-on releasable attachment of the actuator to a handle . According to another aspect of the invention, a medical instrument includes a handle, an actuator for controlling an end effector, the actuator including a proximal portion with a tapered end section and a groove located distally of the tapered end section, and a coupler for connecting the actuator to the handle. The coupler includes an opening for receiving the actuator proximal portion and a spring loaded mechanism movable between a first position extending into the opening for engaging the groove and a second position allowing passage of the proximal portion through the opening, the tapered end acting to move the spring loaded mechanism toward the second position during insertion of the proximal portion into the opening. Preferred embodiments of this aspect of the invention may include one or more of the following features . A release mechanism is coupled to the spring loaded mechanism for moving the spring loaded mechanism toward the second position to allow removal of the proximal portion from the opening. The release mechanism is a spring loaded pin. The coupler is attached to the handle to rotate with respect to the handle. According to another aspect of the invention, a medical instrument includes a handle, an actuator, a coupler for connecting the actuator to the handle, and an end effector attached to a actuator. Preferred embodiments of this aspect of the invention may include one or more of the following features . A shaft surrounds the actuator. The end effector includes a plurality of implements mounted to the shaft. At least one of the implements is detachable from the shaft and the actuator and from another one of the implements. The shaft includes spring arms detachably coupled to the end effector. A sheath surrounds the shaft. According to another aspect of the invention, a detachable medical instrument incudes an actuator for controlling an end effector. The actuator includes a proximal portion having a tapered end section and a groove located distally of the tapered end section for snap-on detachable coupling of the actuator to a handle. A sheath is detachably coupled to the actuator. According to another aspect of the invention, a medical instrument includes a coupler mounted to a handle for rotation relative to the handle. The coupler includes an opening for receiving an actuator, a spring loaded mechanism movable between a first position extending into the opening for engaging the actuator and a second position allowing passage of a portion of the actuator through the opening, a release mechanism coupled to the spring loaded mechanism for moving the spring loaded mechanism toward the second position to allow removal of the portion from the opening, and a positioning member which interfaces with the handle to position the coupler in a desired rotated position relative to the handle. According to another aspect of the invention, an end effector for a medical instrument of the kind that includes an actuating member for actuating the end effector has a pair of implements configured for releasable connection to each other and to the actuating member . Preferred embodiments of this aspect of the invention may include one or more of the following features . Each of the pair of implements includes a working portion, a coupler in the form of a coupling pin which is received in a corresponding slot in the actuating member, and a coupler configured for releasably connecting the pair of implements to each other. According to another aspect of the invention, a detachable medical instrument includes an actuator and a distal assembly. A distal coupler of the actuator and a proximal coupler of the distal assembly detachably engage. The distal coupler and the proximal coupler are configured to be non-fixedly engaged together when one of the distal coupler and the proximal coupler is in a first orientation. The distal coupler and the proximal coupler are configured to be fixedly engaged together when the one of the distal coupler and the proximal coupler is moved from its first orientation to a second orientation. Preferred embodiments of this aspect of the invention may include one or more of the following features . The distal coupler includes a head portion, and the proximal coupler defines a cavity with an aperture to non-fixedly receive the head portion when the one of the distal coupler and the proximal coupler is in the first orientation. The cavity fixedly receives the head portion when the one of the distal coupler and the proximal coupler is in the second orientation. The distal coupler includes a stem portion and a head portion adjacent the stem portion. The stem portion is in the form of a first cylinder having a central axis extending along a longitudinal axis of the instrument, and the head portion is in the form of a second cylinder having a central axis extending along an axis transverse to the longitudinal axis. The diameter of the head portion is a greater than a width of the head portion. The cavity of the proximal coupler has a slotted region and an aperture region adjacent the slotted region. The slotted region is in the form of a third cylinder having a central axis extending along a longitudinal axis of the instrument, and the aperture region is in the form of a fourth cylinder having a central axis extending along an axis transverse to the longitudinal axis. A diameter of the slotted region is greater than the width of the head portion and less than the diameter of the head portion. A diameter of the aperture region is greater than the diameter of the head portion. The distal assembly includes a paddle and a surgical implement. The proximal coupler is located at a proximal end of the paddle. The surgical implement is attached to a distal end of the paddle. The distal end of the paddle includes an inclined slot. The implement is coupled to the slot such that axial movement of the actuator causes pivotal movement of the implement . According to another aspect of the invention, a method of assembling a medical instrument includes positioning a distal coupler of an actuator in a first orientation with respect to a proximal coupler of a distal assembly such that the distal coupler and the proximal coupler are non-fixedly engaged together; and moving one of the distal coupler and the proximal coupler relative to the other of the distal coupler and the proximal coupler to a second orientation to fixedly engage the actuator to the distal assembly. Preferred embodiments of this aspect of the invention may include one or more of the following features . One of the distal coupler and the proximal coupler is rotated between the two orientations. One of the distal coupler and the proximal coupler is moved relative to the other from the second orientation to the first orientation to allow the actuator and the distal assembly to be detached. The medical instruments of the invention may be used in arthroscopic procedures in which, for example, scissors or graspers are employed. The medical instruments can be adapted to connect to a power source for use in procedures where cauterization capability is desired. Advantages of the invention include detachable implements which permit replacement of the distal assembly or individual replacement of dulled blades, thus providing a cost effective disposable system. Additionally, instruments according the invention can be quickly disassembled such that components can be individually cleaned and easily reassembled. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims. Brief Description of the Drawings Fig. 1 is a diagrammatic illustration of a medical instrument ; Fig. 2 is an exploded view of the medical instrument of Fig. 1 ; Figs. 3 and 3A are diagrammatic illustrations of an end effector of the medical instrument of Fig. 1; Fig. 4 is a cross-sectional view of the distal end of the medical instrument of Fig. 1, shown with an outer tube removed; Fig. 4A is a diagrammatic illustration of the distal end the medical instrument of Fig. 1, showing an actuator coupled to an end effector; Fig. 5 is a diagrammatic illustration of the distal end of the medical instrument of Fig. 1, shown with an outer tube removed; Fig. 6 is a cross-sectional view of a coupler of the medical instrument of Fig. 1, shown with a cover removed; Fig. 6A is an end view of the coupler, taken along lines 6A-6A in Fig. 6; Fig. 7 is a diagrammatic illustration of an additional embodiment of a medical instrument; Fig. 8 is an exploded view of the medical instrument of Fig. 7; Figs. 9 and 9A are diagrammatic illustrations of an alternative embodiment of an end effector of the medical instrument of Fig. 1 ; Figs. 10 and 10A are diagrammatic illustrations of an additional alternative embodiment of an end effector of the medical instrument of Fig. 1; Fig. 11 is a diagrammatic illustration of an additional embodiment of a medical instrument; Fig. 11A is a side view of a distal coupler of the medical instrument of Fig. 11; Fig. 11B is and end view of the distal coupler of Fig. 11A, taken along lines 11B-11B of Fig. 11A; Fig. 11C is an end view of a proximal coupler of the medical instrument of Fig. 11, taken along lines 11C- 11C of Fig. 11; Fig. 11D is a perspective view of the proximal coupler of the medical instrument of Fig. 11; Figs. 12 and 12A are side and end views of the medical instrument of Fig. 11 shown in a first, non- fixedly engaged position; Fig. 13 shows the medical instrument of Fig. 11 in a second, fixedly engaged position; Figs. 14-14B are illustrations of an implement and paddle of the medical instrument of Fig. 11; Fig. 14C is an illustration of an actuator and housing of the medical instrument of Fig. 11; Fig. 14D is an illustration of the medical instrument of Fig. 11 shown rotated 90° with respect to Fig. 14C; Fig. 14E is an illustration of the medical instrument of Fig. 11 shown with an outer tube; Fig. 14F is an end view of the outer tube, taken along lines 14F-14F of Fig. 14E; Figs. 15-15D are illustrations of an additional alternative embodiment of a medical instrument; Fig. 16 is an exploded view of an additional alternative embodiment of a medical instrument; Figs. 17 and 17A are illustrations of an additional alternative embodiment of a medical instrument ; and Figs. 18 and 18A are top and side views of a handle and coupler of a medical instrument; and Fig. 18B is an illustration of the proximal ends of the actuator, housing, and outer tube of the medical instrument . Description of the Preferred Embodiments Referring to Fig. 1, an arthroscopic instrument 210 includes a handle 212, a coupler 214 with base section 216 and cover 218, and a tube assembly 220 with a detachable end effector 222, e.g., a scissor dissector. Handle 212 has an electrical connector 213 which attaches to a power source (not shown) to permit cauterization of tissue with end effector 222. End effector 222 includes implements 250, 252, e.g., cutting blades, which become dulled with use. In order to replace one or both dulled implements, implements 250, 252 are individually detachable from each other and from tube assembly 220. Referring to Fig. 2, end effector 222 is detachably coupled to an actuator 230 and an intermediate shaft 231 of tube assembly 220. Actuator 230 terminates in a distal coupler 241, and shaft 231 terminates in a distal coupling section 235 with spring arms 233, described further below, for detachably coupling end effector 222 to actuator 230 and shaft 231. An outer sheath 232 of tube assembly 220 is hollow to accommodate the insertion of shaft 231 into sheath 232, and shaft 231 is hollow to accommodate the insertion of actuator 230 into shaft 231. Shaft 231 includes a proximal section 237 with external threads 237a which extend beyond a proximal end 239 of sheath 232 when tube assembly 220 is assembled. A spacer 256 has a distal section 256a with internal threads 257 for threaded engagement with proximal threads 237a of shaft 231 and a proximal, enlarged section 256b. Section 256b has a knurled edge 256c to aid in threading spacer 256 onto shaft 231. Alternatively, instead of spacer 256 being a separate component, spacer 256 can be integral with sheath 232. When instrument 210 is assembled spacer 256 is positioned between base section 216 and cover 218 to prevent axial movement of shaft 231 and sheath 232 when actuator 230 is moved axially. A distal end 236 of shaft coupling section 235 has an increased outer diameter against which a distal end 234 of sheath 232 abuts when assembled. With tube assembly 220 assembled, a proximal end 248 of actuator 230 extends outside proximal section 237 of shaft 231. Proximal end 248 of actuator 230 includes a tapered portion 252, a groove 249, and a flattened section 261 (there being a corresponding flattened section, not shown, on the opposite side of proximal end 248) for coupling actuator 230 to coupler base section 216, described further below. Groove 249 has a width, e.g., of about 0.045", a diameter, e.g., of about 0.065", and actuator 230 has a diameter, e.g., of about 0.095". Referring to Figs. 3 and 3A, implements 250, 252 of end effector 222 include coupling members 251, 253, respectively, having shaft couplers 254, 254a, respectively, through which a pin 259 passes to attach implements 250, 252 to each other. Pin 259 can be integral with one of the implements 250, 252, or not. Implements 250, 252 rotate with respect to each other about pin 259 to open and close. Implements 250, 252 includes cutting edges 255, 255a, respectively, and are arched with surface 257 of implement 250 contacting a corresponding surface (not shown) of implements 252. Referring to Figs. 4 and 4A, distal coupler 241 of actuator 230 includes a slot 260 on one face 262 of distal coupler 241 and a second slot 264 located on the opposite face 266 of distal coupler 241. As seen in fig. 4, slots 260, 264 are inclined to form an "X". An actuator coupling pin 258a (Fig. 3A) of implement 250 is positioned in slot 264 and an actuator coupling pin 258b of implement 252 is positioned in slot 260. Referring to Fig. 5, spring arms 233 each include a hole 280, only one hole being shown, for receiving a respective coupler 254 of implements 250, 252 to attach the implements to shaft 231. With shaft 231 holding implements 250, 252 axially stationary during axial, proximal motion of actuator 230 (arrow 270, Fig. 4) , actuator coupling pins 258a, 258b slide within slots 264, 260, respectively, while slots 260, 264 move proximally. Due to the inclination of slots 260, 264 relative to the axial direction, moving actuator 230 proximally causes implements 250, 252 to open. During distal motion of actuator 230 (arrow 272, Fig. 4A) , actuator coupling pins 258a, 258b slide within slots 260, 264 while slots 260, 264 move distally. Moving actuator 30 distally causes implements 250, 252 to close. Spring arms 233 are outwardly flexible to permit insertion of end effector 222 into shaft 231. A cap 223 (Fig. 2) can be used to help hold implements 250, 252 together during assembly. To assemble tube assembly 220, actuator 230 is first placed within shaft 231 with distal coupler 241 extending out of distal end 236 of shaft 231. Actuator coupling pins 258a and 258b of implements 250, 252 are placed in slots 264, 260, respectively. To aid in the placement of coupling pins into slots 264, 260, each pins 258a, 258b is initially positioned in a detent 243 located on distal coupler 241 (see Fig. 2, a corresponding detent, not shown, being located on the opposite side of distal coupler 241) . Detents 243 are aligned with slots 264, 260 such that after placement of pins 258a, 258b in detents 243, pushing implements 250, 252 proximally locates pins 258a, 258b in the proximal ends of slots 264, 260. Actuator 230 is then pulled proximally such that distal coupler 241 is located within shaft 231. Arms 233 of shaft 231 are flexed outward to enable couplers 254, 254a to be aligned with holes 280 in shaft 231. Arms 233 are then released resulting in couplers 254, 254a being located in holes 280. Outer sheath 232 is then slid over shaft 231 and adapter 256 is threaded onto proximal section 237 of shaft 231. To remove implements 250, 252 from actuator 230 and shaft 231, outer sheath 232 and adapter 256 are removed from shaft 231 and actuator 230 surrounded by shaft 231 is connected to coupler 214, described further below. By holding shaft 231 while rotating coupler 214 (which causes rotation of actuator 230) arms 233 of shaft 231 are flexed outward by distal coupler 241 of actuator 230 causing implements 250, 252 to be released from holes 280 in shaft 231 and removed from actuator 230. The releasable coupling of implements 250, 252 to each other and to actuator 230 and shaft 231 enables one or both implements 250, 252 to be replaced when worn. Referring to Fig. 6, in which coupler 214 is shown with cover 218 removed, the base section 216 of coupler 214 includes a housing 60 with a through channel 64. A coupling member 66 located in channel 64 has a through bore 68 for receiving proximal end 248 of actuator 230. Channels 70, 72 in coupling member 66 intersect bore 68 and house a pin 74 and spring 76 for loading pin 74. A hole 82 in pin 74 permits passage of actuator 230 through pin 74. Spring 76 biases pin 74 upwardly, as viewed in Fig. 6, such that a wall 80 of hole 82 extends into bore 68 of coupling member 66. Tapered portion 252 on proximal end 248 helps to guide actuator 230 into bore 68 during insertion of actuator 230 into coupler 214 and acts to push pin 74 downwardly against the force of spring 72 to move wall 80 out of through bore 68. When groove 249 of actuator 230 is aligned with wall 80, pin 74 moves upward due to the force of spring 76, and wall 80 moves into position in groove 249 to lock actuator 230 to base section 216. To remove actuator 230 from coupling member 66, pin 74 is manually depressed against the force of spring 76 to disengage wall 80 from groove 249. Referring to Fig. 6A, bore 68 has flattened sides 68a, 68b. Actuator 230 is placed in bore 68 with flats 261 aligned with bore flats 68a, 68b. Actuator 230 is thus keyed to bore 68 such that rotation of coupler 214 also causes rotation of actuator 230. Referring again to Fig. 6, housing 60 includes an externally threaded section 62 for attachment of internal threaded cover 218 over housing 60. With actuator 230 locked into position in housing 60, spacer 256 abuts a distal surface 84 of housing 60. Cover 218 captures spacer 256 against surface 84 when threaded onto housing 60 to prevent axial movement of spacer 256, and thus shaft 231 and sheath 232, during axial movement of actuator 230. Handle 212 is coupled to actuator 230 and member 66 by a trigger rod 90. A distal end 92 of trigger rod 90 abuts coupling member 66 and includes a distal cut out 93 for receiving actuator 230. A proximal end 94 of trigger rod 90 is coupled to a pivotable trigger 96 of handle 212. Actuation of trigger 96 causes axial movement of trigger rod 90 and thus axial motion of coupling member 66 and actuator 230. Slots 100, 102 in housing 60 provide clearance for movement of pin 74 with coupling member 66. Handle 212 includes an integral mount 110 for rotatably mounting housing 60 to handle 212. A circumferential groove 112 in housing 60 contains an o- ring 114 providing a seal between housing 60 and mount 110. A second o-ring 116 located in a second circumferential groove 118 in mount 110 also provides a seal between housing 60 and mount 110. A third circumferential groove 120 in mount 110 includes surface detentes 122 spaced around the circumference of groove 120. A dowel pin 124 and a ball plunger 126 extend through housing 60 to groove 120. Dowel pin 124 is press fit into place to couple mount 110 to housing 60 while permitting rotation of housing 60 relative to mount 110. Ball 126a of ball plunger 126 is spring biased to enter detentes 122 as housing 60 is rotated to aid in rotationally positioning housing 60, and thus end effector 222. In use, cover 218 is placed onto sheath 232 and actuator 230, shaft 231 and end effector 222 are assembled and positioned within sheath 232 to form tube assembly 220 (Fig. 2) . Tube assembly 220 is then coupled to base section 216 of coupler 214 by "snapping" proximal end 248 of actuator 230 into place, and cover 218 is threaded onto base section 216 to capture spacer 248. Instrument 210 can be easily disassembled for cleaning. Tube assembly 220 can be easily removed from base section 216 by removing cover 218, depressing pin 74, and removing proximal end 248 of actuator 230 from base section 216. Tube assembly 220 can then be disassembled to permit cleaning of actuator 230, shaft 231, sheath 232, and end effector 222, and to permit replacement of one or both implements 250, 252. The coupling mechanism for joining actuator 230 to coupler 214, described above, provides a simple method of attaching and detaching tube assembly 220 and coupler 214. Coupler 214 is not limited to use with tube assembly 220 and can be used with any medical instrument having an actuator with a proximal end 248 for "snap-on" joining to coupler 214. Referring to Fig. 7, an arthroscopic instrument 10 includes a handle 12, a handle lock 15, a coupler 14 with a base section 16 and a cover 18, identical to coupler 214 described above, and a tube assembly 20 with a distal end effector 22, e.g., a grasper or dissector. End effector 22 may include one or more moveable members 23. Tube assembly 20 is removable from coupler 14 and can be disassembled, described below, to facilitate cleaning of instrument 10. Referring to Fig. 8, tube assembly 20 includes an actuator 30 terminating in distal end effector 22, and a hollow outer sheath 32 through which actuator 30 is placed (shown in phantom) . Actuator 30 includes a rod 40 and a distal tube 42 radially spaced from rod 40 which are both coupled to end effector 22 as described, e.g., in U.S. Patent No. 4,712,545 to Honkanen, incorporated by reference herein. Tube 42 has an internally threaded section 44. Sheath 32 has a proximal section 46 with external threads 46a for attaching actuator 30 to sheath 32 by insertion of section 46 into tube 42 (shown in phantom) and threaded engagement of sections 44 and 46. In an alternative, preferred embodiment, tube 42 is externally threaded at section 44 and sheath 32 is internally threaded at proximal section 46. With actuator 30 positioned inside and threadedly attached to sheath 32, a proximal end 48 of actuator 30 extends outside a proximal end 50 of sheath 32 (shown in phantom) . Proximal end 48 of actuator 30 includes a tapered portion 52 and a groove 49 for coupling actuator 30 to coupler base section 16, as described above. Proximal end 50 of sheath 32 includes a spacer 56 which, when instrument 10 is assembled, is captured between base section 16 and cover 18 to prevent axial movement of sheath 32, and thus tube 42, when actuator 30 is moved axially. In use, cover 18 is placed onto sheath 32 and actuator 30 is positioned within sheath 32 to form tube assembly 20. The tube assembly 20 is then coupled to base section 16 of coupler 14 by "snapping" proximal end 48 of actuator 30 into base section 16, and cover 18 is threaded onto base section 16. Tube assembly 20 can be easily removed from base section 16 by removing cover 18, depressing pin 74, and removing proximal end 48 of actuator 30 from base section 16. Tube assembly 20 can then be disassembled by unscrewing sheath 32 from actuator 30 to permit cleaning of actuator 30, sheath 32, and end effector 22. End effector 22 can be coupled to tube assembly 20 in the manner described above with reference to Figs. 4- 5. Other embodiments are within the scope of the following claims. For example, referring to Figs. 9 and 9A, actuator distal coupler 241 can be used with an end effector 322, e.g., a grasper or cutter, having a fixed implement 350 and a movable implement 352. Implements 350, 352 include coupling members 351, 353, respectively, having shaft couplers 354, 354a. Coupling member 351 of movable implement 352 includes an actuator coupling pin 358 which is positioned in slot 264 of coupler 241 such that movement of actuator 230 causes implement 252 to open and close as described above. Coupling member 353 of fixed implement 350 does not include an actuator coupling pin and has a contoured outer surface 353a having a radius corresponding to the inner radius of shaft 231. Fixed implement 350 is therefore not coupled to actuator 230 and contoured surface 353a insures that implement 350 remains stationary during axial movement of actuator 230 to open and close movable implement 352. Referring to Figs. 10 and 10A, alternatively, coupling member 353 of fixed implement 350 has a fixation knob 353b which abuts shaft 231 to insure that implement 350 remains stationary during axial movement of actuator 230 to open and close movable implement 352. Referring to Fig. 11, an arthroscopic instrument 430 includes an actuator 400 detachably mounted to a paddle 402 coupling actuator 400 to an implement 404. Here a scissors-type implement is shown. A distal end 406 of actuator 400 includes a head 408 extending from a stem 410. To attach actuator 400 to paddle 402, distal end 406 is inserted into a cavity 412, defined in a proximal end 414 of paddle 402. Referring to Figs. 11A and 11B, in which actuator 400 is shown rotated 90° with respect to Fig. 11, stem 410 of actuator 400 has a circular cross-section with a diameter (a) . Head 408 is asymmetrically shaped with a width (b) , less than diameter (a) , and a diameter (c) , greater than diameter (a), in a direction transverse . to width (b) . Width (b) extends between two flat, opposed surfaces 416, and diameter (c) is defined by opposed arc surfaces 417. Stem 410 is thus a cylinder having its central axis, W, aligned along a longitudinal axis, A, of instrument 430, and head 408 is a disk shaped cylinder having its central axis, X, aligned along an axis, B, perpendicular to axis, A. Cavity 412 includes a slot 418 for receiving stem 410 and an aperture 428 for receiving head 408. Referring to Figs. 11C and 11D, slot 418 is defined by opposed curved surfaces 420, 421 of paddle 402. Slot 418 is cylindrically shaped with a central axis, Y, aligned along longitudinal axis, A. Curved surfaces 420, 421 are separated by a diameter (d) , defined by curved surfaces 420, 421, and a minimum dimension (e) at an edge 426 of paddle 402. For reasons described below, slot diameter (d) is greater than stem diameter (a) and less than head diameter (c) , and slot dimension (e) is less than stem diameter (a) and greater than head width (b) . Referring to Fig. 11D, aperture 428 of cavity 412 is a cylindrical hole defined by paddle 402 having its central axis, Z, extending along axis, B. Aperture 428 has a diameter (f) greater than head diameter (c) . Stop surfaces 432 are defined by paddle 402 in the region where aperture 428 meets slot 418. Referring to Figs. 12 and 12A, when inserting distal end 406 into cavity 412, actuator 400 is oriented with respect to paddle 402 such that sides 416 of head 408 are facing curved walls 420, 421 of slot 418. Head 408 can be advanced through slot 418 because head width (b) is less than slot dimension (e) . Stem 410 can be advanced into slot 418 because stem diameter (a) is less than slot diameter (d) . Distal end 406 is advanced into cavity 412 until head 408 is positioned within aperture 428. In this position, actuator 400 is non-fixedly engaged to paddle 402. Referring to Fig. 13, to fixedly engage actuator 400 to paddle 402, one of actuator 400 or paddle 402 is rotated 90° about axis, A. This results in head diameter (c) being aligned with aperture diameter (f) . In this orientation, head 408 is captured within aperture 428 such that detachment of actuator 400 from paddle 402 in a direction along axis, A, is prevented by contact of head 408 with stop surfaces 432. Stem 410 is captured within slot 418 such that detachment of actuator 400 from paddle 402 in a direction along axis, B, is prevented by contact of stem 410 against edge 426. To detach actuator 400 from paddle 402, one of actuator 400 and paddle 402 is rotated 90 degrees and paddle 402 and actuator 400 are pulled apart. The removable connection of paddle 402 and actuator 400 permits paddle 402 with implement 404 to be replaced when implement 404 becomes dull. Stem diameter (a) is, e.g., 0.059 inch; head width (b) is, e.g., 0.049 inch; head diameter (c) is, e.g., 0.092 inch; slot diameter (d) is, e.g., 0.061 inch; slot dimension (e) is, e.g., 0.050 inch; and aperture diameter (f) is, e.g., 0.093 inch. Referring to Figs. 14-14B, implement 404 includes blades 432, 434 attached to paddle 402 by a pin 438 which passes through a pair of outer blade hubs 440 located on blades 432, 434 and through a slot 435 in paddle 402. Blades 432, 434 can rotate about pin 438. Paddle 402 includes two slots 454, one on either side, as discussed above with reference to Figs. 4 and 4A, in which a pair of blade inner hubs 456 are slidably received. Referring to Figs. 14C-14F, a housing 446 is positioned over actuating rod 400 and has distal arms 448 with holes 450. Housing 446 is attached to blades 432, 434 by positioning holes 450 over outer blade hubs 440. An outer tube 452 includes a through bore 453 and is received over housing 444. When outer tube 452 is slid distally, the outer tube acts to close arms 448 over blade hubs 440. Distal and proximal axial movement of actuating rod 400, and thus paddle 402, while housing 446 remains stationary causes blades 432, 434 to open and close. Actuating rod 400 has a set screw 458 near its proximal end 522 which slides within two slots 460, one on either side, of housing 446. Slots 460 do not extend the entire length of housing 446. Actuating rod 400 is thus telescopically received in housing 446 but prevented from being completely removed from the housing by set screw 458. The telescoping action and slots 460 in housing 446 facilitate cleaning of actuating rod 400 and housing 446. Set screw 458 also prevents actuating rod 400 from rotating within housing 446. The proximal ends of actuating rod 400, housing 446 and outer tube 452 are described further below. Referring to Fig. 15-15D, scissor-type instrument 470 is similar to scissor instrument 430 except blades 472, 474 are of simpler construction with no outer hubs. Blades 472, 474 are attached to paddle 476 using a collar 478 and a pin 480. Collar 478 is also used to couple blades 472, 474 and paddle 402 assembly to housing 482. Housing 482 includes arms 484 having distal notches 486 which act to grasp collar 478. When an outer tube 482 is slid distally, outer tube 482 acts to close arms 484 over collar 478. Referring to Fig. 16, grasper jaws 490, 492 attach to paddle 436 and to housing 446 as described above with reference to Figs 14-14F. Paddle 436 is attached to actuating rod 444, for example, by soldering paddle notch 440 to the distal end of actuating rod 444. Each of the jaws 490, 492 includes interlocking sections 84, 86 which interlock with the sections on the opposite jaw to prevent misalignment of the jaws. Referring to Fig. 17-17A, jaw mechanism 500 is of the dovetail design (as described in U.S. Patent No. 4,712,545, supra). Housing 502 is similar to housing 446 of Figs. 14-14F with notched arms 504, 504a closing around a proximal hub 506 such that fingers 505, 505a sit within a groove 507 of hub 506 to attach jaw mechanism 500 to the housing. Jaw mechanism 500 is attached to an actuating rod 508. Note that in this embodiment, an outer tube 508 is moved to cover jaw mechanism 500 while in all other embodiments it is exposed. By covering the jaw mechanism, contact of the mechanism with tissue is avoided. Referring to Figs. 14C-14F and Figs. 18-18B, proximal ends 522, 515, 513 of actuator 400, housing 446 and outer tube 452, respectively, couple to a handle 510. Handle 446 includes a coupling hub 514 having two opposed flattened surfaces 514a, 514b. Proximal end 522 of actuator 400 includes a stem section 522a and a ball section 522b which extend beyond proximal end 515 of housing 446, as shown in Fig. 18B. Handle 510 includes a handle actuator 518 with a cut-out 520 having a stem-shaped first portion 520a for receiving stem section 522a of proximal end 522, and a ball-shaped second portion 520b for receiving ball section 522b of proximal end 522. A coupler housing 524 rotatably attached to handle 510 has a cut-out 526 in which coupling hub 514 of housing 446 is received. Cutouts 520, 526 are open to the side of the housing to permit proximal end 522 of actuator rod 400 and coupling hub 514 to be slid into the cut-outs. Cut-out 526 has side flats 550 over which flattened surfaces 514a, 514b are received to align the coupling hub with the cut-out and to prevent rotation of the coupling hub within the cut-out. Thus, housing 446 and actuator 400 rotate only when coupler housing 524 is rotated by the user. A finger loop 528 of handle 510 is used to move handle actuator 518 axially which in turns moves actuator 400 axially to open and close the scissors, graspers, or dissectors. A lock screw 530 limits the axial motion of handle actuator 510. A nose piece 532 locks coupling hub 514 and proximal end 522 of actuator 400 in place. Other embodiments are within the scope of the following claims. What is claimed is:

Claims: 1. A medical instrument, comprising: an elongated shaft, a plurality of implements mounted to said shaft, and an actuator coupled to produce relative movement between said implements, at least one of said implements being detachable from said shaft and said actuator and from another one of said implements. 2. The medical instrument of claim 1 wherein said actuator includes a distal portion with an inclined slot, one of said implements being detachably coupled to said slot such that movement of said actuator causes said relative movement between said implements. 3. The medical instrument of claim 2 wherein said distal portion includes a plurality of inclined slots, each of said implements being detachably coupled to one of said slots. 4. The medical instrument of claim 1 wherein said shaft includes spring arms detachably coupled to said implements. 5. The medical instrument of claim 1 wherein said actuator includes a proximal portion for snap-on releasable attachment of said actuator to a handle. 6. The medical instrument of claim 1 wherein said implements are scissors mounted to pivot open and closed. 7. A medical instrument, comprising: an elongated shaft, first and second implements mounted to said shaft, said implements being detachable from said shaft and from each other, and an actuator detachably coupled to produce relative movement between said implements, said actuator including a distal portion with first and second oppositely inclined slots, said first implement being detachably coupled to said first slot and said second implement being detachably coupled to said second slot such that movement of said actuator causes said relative movement between said implements. 8. The medical instrument of claim 7 wherein said shaft includes spring arms detachably coupled to said implements. 9. A medical instrument, comprising: a handle, an actuator for controlling an end effector, said actuator including a proximal portion with a tapered end section and a groove located distally of said tapered end section, and a coupler for connecting said actuator to said handle, said coupler including an opening for receiving said actuator proximal portion and a spring loaded mechanism movable between a first position extending into said opening for engaging said groove and a second position allowing passage of said proximal portion through said opening, said tapered end acting to move said spring loaded mechanism toward said second position during insertion of said proximal portion into said opening. 10. The medical instrument of claim 9 further comprising a release mechanism coupled to said spring loaded mechanism for moving said spring loaded mechanism toward said second position to allow removal of said proximal portion from said opening. 11. The medical instrument of claim 10 wherein said release mechanism comprises a spring loaded pin. 12. The medical instrument of claim 9 wherein said coupler is attached to said handle to rotate with respect to said handle. 13. A medical instrument, comprising: a handle, an actuator including a proximal portion with a tapered end section and a groove located distally of said tapered end section, a coupler for connecting said actuator to said handle, said coupler including an opening for receiving said actuator proximal portion and a spring loaded mechanism movable between a first position extending into said opening for engaging said groove and a second position allowing passage of said proximal portion through said opening, said tapered end acting to move said spring loaded mechanism toward said second position during insertion of said proximal portion into said opening, and an end effector attached to said actuator. 14. The medical instrument of claim 13 further comprising a shaft surrounding said actuator. 15. The medical instrument of claim 14 wherein said end effector includes a plurality of implements mounted to said shaft, at least one of said implements being detachable from said shaft and said actuator and from another one of said implements. 16. The medical instrument of claim 14 wherein said shaft includes spring arms detachably coupled to said end effector. 17. The medical instrument of claim 14 further comprising a sheath surrounding said shaft. 18. A detachable medical instrument, comprising: an actuator for controlling an end effector, said actuator including a proximal portion having a tapered end section and a groove located distally of said tapered end section for snap-on detachable coupling of said actuator to a handle, and a sheath detachably coupled to said actuator. 19. A medical instrument comprising: a coupler mounted to a handle for rotation relative to the handle, said coupler including an opening for receiving an actuator, a spring loaded mechanism movable between a first position extending into said opening for engaging said actuator and a second position allowing passage of a portion of said actuator through said opening, a release mechanism coupled to said spring loaded mechanism for moving said spring loaded mechanism toward said second position to allow removal of said portion from said opening, and a positioning member which interfaces with the handle to position said coupler in a desired rotated position relative to the handle. 20. An end effector for a medical instrument of the kind that includes an actuating member for actuating the end effector, comprising: a pair of implements configured for releasable connection to each other and to the actuating member. 21. The end effector of claim 20 wherein each of said pair of implements includes a working portion. 22. The end effector of claim 20 wherein each of said pair of implements includes a coupler configured to engage the actuating member. 23. The end effector of claim 22 wherein said coupler comprises a coupling pin which is received in a corresponding slot in the actuating member. 24. The end effector of claim 20 wherein each of said pair of implements includes a coupler configured for releasably connecting said pair of implements to each other. 25. A detachable medical instrument comprising: an actuator having a distal coupler; a distal assembly having a proximal coupler for detachable engagement with the actuator distal coupler, wherein the distal coupler and the proximal coupler are configured to be non-fixedly engaged together when one of the distal coupler and the proximal coupler is in a first orientation, the distal coupler and the proximal coupler being configured to be fixedly engaged together when the one of the distal coupler and the proximal coupler is moved from its first orientation to a second orientation. 26. The medical instrument of claim 25 wherein the distal coupler includes a head portion, the proximal coupler defining a cavity with an aperture to non-fixedly receive the head portion when the one of the distal coupler and the proximal coupler is in the first orientation, and fixedly receive the head portion when the one of the distal coupler and the proximal coupler is in the second orientation. 27. The medical instrument of claim 25 wherein the distal coupler includes a stem portion and a head portion adjacent the stem portion, the stem portion being in the form of a first cylinder having a central axis extending along a longitudinal axis of the instrument, and the head portion being in the form of a second cylinder having a central axis extending along an axis transverse to the longitudinal axis. 28. The medical instrument of claim 27 wherein a diameter of the head portion is a greater than a width of the head portion. 29. The medical instrument of claim 28 wherein the proximal coupler defines a cavity having a slotted region and an aperture region adjacent the slotted region, the slotted region being in the form of a third cylinder having a central axis extending along a longitudinal axis of the instrument, and the aperture region being in the form of a fourth cylinder having a central axis extending along an axis transverse to the longitudinal axis, a diameter of the slotted region being greater than the width of the head portion and less than the diameter of the head portion, and a diameter of the aperture region being greater than the diameter of the head portion. 30. The medical instrument of claim 25 wherein said distal assembly comprises: a paddle, the proximal coupler being located at a proximal end of the paddle, and a surgical implement attached to a distal end of the paddle. 31. The medical instrument of claim 30 wherein the distal end of the paddle includes an inclined slot, the implement being coupled to the slot such that axial movement of the actuator causes pivotal movement of the implement . 32. A method of assembling a medical instrument comprising: positioning a distal coupler of an actuator in a first orientation with respect to a proximal coupler of a distal assembly such that the distal coupler and the proximal coupler are non-fixedly engaged together, and moving one of the distal coupler and the proximal coupler relative to the other of the distal coupler and the proximal coupler to a second orientation to fixedly engage the actuator to the distal assembly. 33. The method of claim 32 wherein moving the one of the distal coupler and the proximal coupler comprises rotating the one of the distal coupler and the proximal coupler. 34. The method of claim 32 further comprising moving one of the distal coupler and the proximal coupler relative to the other of the distal coupler and the proximal coupler from the second orientation to the first orientation to allow the actuator and the distal assembly to be detached.

Inventors: BOURQUE BERNARD J, LIZARDI JOSE, BOURQUE, BERNARD, J., LIZARDI, JOSE
Applicants: BOURQUE BERNARD J, LIZARDI JOSE, SMITH & NEPHEW INC, BOURQUE, BERNARD, J., LIZARDI, JOSE, SMITH & NEPHEW, INC.
Application year: 1998
Main classification: A61B17
IPC codes: A61B17