Thumb-activated actuating member for endoscopic surgical instrument

Abstract: An actuator 50 for a laparoscopic surgical instrument (10) imparts reciprocal motion to a push rod 60 surrounded by a hollow tube (15). The actuator includes a plastic housing 914 which fixedly engages the hollow tube, and a lever 420 which fixedly engages the push rod and pivotally engages the housing. The housing also preferably includes an integral handle 410. When the handle and lever are manipulated by the user such as by pivotal movement of the lever, reciprocal motion is imparted to the push rod relative to the hollow tube. The lever also includes an external unevenly surfaced portion 410 which when frictionally engaged by a digit of a human hand will impart pivotal motion to the lever, and hence reciprocal motion to the push rod.

Description: BACKGROUND OF THE INVENTION The present invention broadly relates to endoscopic surgical instruments. More particularly, the invention relates to surgical instruments which include end effectors such as cutters, graspers, and dissectors which are useful in endoscopy and laparoscopy procedures and which may be disposed of after a single use. The endoscopy and laparoscopy procedures have recently become widely practiced surgical procedures. The endoscopy and laparoscopy procedures involve incising through body walls (e.g., such as the abdominal wall) for examining, viewing and/or operating on the ovaries, uterus, gall bladder, bowels, appendix, etc. or for general abdominal surgery. Typically, trocars are utilized for creating the incisions. Trocar tubes are left in place in the abdominal wall so that the endoscopic or laparoscopic surgical tools may be inserted through the tube. A camera or magnifying lens is often inserted through the largest diameter trocar tube (e.g. 10mm diameter) which for the laparoscopy procedure is generally located at the navel incision, while a cutter, dissector, or other surgical instrument is inserted through a smaller diameter trocar tube (e.g. 5 mm diameter) for purposes of manipulating and/or cutting the internal organ. Sometimes it is desirable to have several trocar tubes in place at once in order to receive several surgical instruments. In this manner, organ or tissue may be grasped with one surgical instrument, and simultaneously may be cut or stitched with another surgical instrument; all under view of the surgeon via the camera in place in the navel trocar tube. The endoscopic and laparoscopic tools of the prior art are primarily reusable stainless steel tools. Between each use of a stainless steel tool, the tool must be soaked, scrubbed, and disinfected. The usual procedure is then to dry the tool, wrap it, and put it in a steam autoclave. The tool is kept sterile until just prior to use when it is removed from the autoclave and unwrapped in the locale of the sterile field of use. While reusable endoscopic/laparoscopic tools have functioned well for their intended purpose, the process of sterilizing the tool is problematic. Small pieces of tissue or organ often become lodged in the end effectors, and much labor is required to ensure that complete sterility is obtained and maintained. In addition, over time, sharp instruments such as a scissors get dull and must be discarded. However, prior to use of a particular instrument, the surgeon is not able to discern the state of the instrument and whether the instrument will satisfy the surgeon's requirements. US-A-4 919 152 is directed to a surgical instrument which is formed of a tubular body and has a manual drive extending theretrough to actuate a pair of jaws at an end of the tubular body between open and closed positions. The instrument is formed with a conduit and valve which provide suction at the remote end of the instrument in the immediate vicinity of the jaws. AU-A-519 691 relates to a finger operated microsurgical instrument comprising a handle and an instrument body rotatably secured to the handle. An operating lever is pivoted to the handle and has a first arm position to be engageable by a surgeons finger while the handle is held in the surgeon's hand and a second arm engages a plunger with the plunger being movable by pivotal movement of the first arm to engage an instrument operating portion within the instrument body to cause operation of the instrument. US-A-4 445 517 relates to a surgical device with a means for controlling a by-directional movement of a surgical instrument longitudinally along an elongated housing. A platform is disposed at a proximal end portion of a tube and a means is associated with the platform for adjusting the magnitude of suction within the housing. Another means is associated with the platform and adjacent to the suction adjusting means for slidably positioning the surgical instrument along the housing. SUMMARY OF THE INVENTION It is an object of the invention to provide endoscopic surgical instruments having improved actuation mechanisms. This object is achieved with a surgical instrument according to claim 1. It is a further object to provide disposable endosopic surgical instruments. This object is achieved with a surgical instrument according to preferred embodiments. In particular, a disposable endoscopic/laparoscopic surgical instrument generally includes, a tube, a push rod which extends through the tube, an actuating means engaging the tube and the push rod for imparting reciprocal axial motion to the push rod, end effector means coupled to the push rod by linkage means which are also coupled to the push rod, and a clevis coupled to the tube at its proximal end and to the end effector means at its distal end, wherein axial movement of the push rod effects movement of the end effector means in a plane parallel to the longitudinal axis of the push rod. Plastic shrink wrap is preferably utilized to electrically insulate the disposable instrument and extends over the aluminum tube and over at least an adjacent portion of the clevis. The actuating means has a housing means fixedly engaging the hollow tube, a lever fixedly engaging the push rod, and a pivot engaging the lever and the housing means for pivotally engaging said lever means relative to the housing means. The pivot extends along a second axis transverse to the longitudinal axis of the hollow tube. According to the invention the lever is provided with an external surface having serration means transverse the longitudinal axis and other than perpendicular to the pivot. The serration means are for being frictionally engaged by a finger of a human hand and imparting pivotal motion to the lever upon movement of the finger relative to said housing. In accord with preferred embodiments of the invention, the tube and push rod are preferably made of aluminum, the clevis is preferably made of a high-strength aluminum alloy, the actuating means is preferably made of plastic and aluminum, and the end effector means is preferably made of investment cast bronze. The clevis of the invention is preferably a separately formed clevis having a knurled rod-like proximal end for mating with the end of the aluminum tube, and a post-supporting U-shaped distal portion for holding the end effector means. The post in the distal portion is perpendicular to the legs of the U-shaped distal portion and is arranged to extend through hole(s) in the end effector means. In this manner, the blades or prongs of the end effector means are held by, but can rotate around the post. Each leg of the U-shaped distal portion of the clevis also preferably includes a notch which serves as a terminating location for the shrink-wrap. Another aspect of the clevis relates to the forming of the post integral with one of the legs of the distal portion of the clevis. The end effector means can take any of many forms, such as, e.g., a scissors, a dissector, a grasper, etc. Additionally, the end effector means can be double acting or single acting. Regardless of the type of end effector utilized, the end effector is arranged with a hole to accept the post of the clevis so that the end effector can rotate around the post. A better understanding of the preferably disposable endoscopic surgical instruments of the invention, and additional advantages and objects of the invention will become apparent to those skilled in the art upon reference to the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevation view, partly in section, of an endoscopic instrument prior to insertion into a trocar tube, and, in partial phantom format, after insertion into a trocar tube; Figure 2a is a side elevation view, partly in section, of the clevis of the instrument in conjunction with the distal end of the tube and shrink wrap; Figure 2b is a cross-section view of the device of Figure 2a; Figure 3a is a partially broken-away side elevation view of the actuating handle of the preferably disposable laparoscopic instrument of the invention; Figure 3b is a rear elevation view of the device of Figure 4a; Figure 4a is a side elevation view, partly in section, of a double acting dissector in conjunction with the clevis and the distal ends of the rod and tube of the preferably disposable laparoscopic instrument of the invention, with the staple linkage means shown in perspective and broken out views; and Figure 4b is a plan view of the device of Figure 5a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to Figure 1, a disposable endoscopic surgical instrument is indicated at 10. The disposable instrument 10 broadly comprises an aluminum tube 15 surrounded by a peripheral insulating shrink wrap layer of plastic 20, a clevis means 30, end effectors 40, actuating means 50, and a push rod 60. The clevis means 30 is advantageously a separately formed aluminum piece which fixedly engages aluminum tube 15 as described in more detail hereinafter. The clevis 30 also engages the end effectors 40 which are pivotally engaged to clevis 30 at pivot pin 45. The end effectors 40 are preferably formed of investment cast bronze. The push rod 60, which is also formed of aluminum, is engaged at its distal end 65 to the end effectors 40, as hereinafter more fully described, and is connected at 70, at its proximal end to a manually operable actuating means 50. For purposes herein, the "distal end" of the instrument 10 or any part thereof, is the end closest to the surgical site and distant from the surgeon, while the "proximal end" of the instrument 10 or any part thereof, is the end most proximate the surgeon and distant the surgical site. In use, the endoscopic/laparoscopic instrument 10 is inserted with the blades or graspers 90, 92 of the end effector 40 in the closed position, into trocar tube 80, as indicated at the arrow 85 of Figure 1. The distal portion of the instrument 10 passes through the trocar tube 80 into body incision 100. Upon the distal portion of the instrument 10 exiting the trocar tube 80, the blades 90, 92 can be opened and closed as indicated at 105 by reciprocal motion of push rod 60 which results from operation of the manual actuating means 50. As is discussed more fully hereinafter, the clevis effectively translates the reciprocal motion of the push rod 60 into the end effector means action indicated at 105. Turning to Figures 2a and 2b, a preferred configuration of the clevis 30 is seen. The clevis has a knurled rod-like proximal portion 34 for mating with the end of the aluminum tube 15, and a post-supporting U-shaped distal portion 32 for holding the end effector means. The outer diameter of the distal portion 32 of the clevis is larger than the outer diameter of the proximal portion 34; shoulder 39 being formed therebetween. The proximal portion 34 of the clevis is preferably hollow, as indicated at 33, to permit the push rod 60 to extend therethrough. The distal portion 32 of the clevis 30 is provided with legs 36 and a post or pivot pin 45. The post 45 is generally perpendicular, i.e. transverse, to the legs 36 of the clevis and is arranged to extend through hole(s) 39 in the end effector means 40. In this manner, the blades or prongs of the end effector means 40 are held by, but can rotate around, i.e. are rotatably engaged with the post 45. As seen in Figure 2a, a recess or notch 380 is provided which extends across each leg 36 of the clevis 30. Consequently, a peripherally applied electrically insulating plastic wrap 20 can be end-cut at recess 380 and a smooth transition from the end effector means 40 via the clevis 30 to tube 15 can be achieved. Even if slight outward flaring of wrap 20 occurs at the end-cut, as is common, this flaring can be tolerated as it will be within the envelope of the normal outer surface indicated at 43. Clevis 30 is preferably made from a high strength aluminum base alloy (e.g. 2024 alloy of Alcoa) which is preferably harder than the aluminum base alloy (e.,g. 6061 or 6063 alloys of Alcoa) from which tube 15 is fabricated. The post portion of the clevis may be made out of the identical alloy or, for added strength, out of a stainless steel nail. In assembly of the laparoscopy surgical instrument 10, serrated or knurled portion 34 of clevis 10 is fit snugly into tube 15 such that the walls of tube 15 abut the peripheral shoulder 39 of clevis 30, with the outer surface of tube 15 and the adjacent outer surface of clevis 30 having essentially the same diameter. Mechanical pressure is then applied to tube 15 peripherally at the location of knurled portion 34, thereby crimping the end portion of tube 15 onto the knurled portion 34. Mechanical pressure causes the projections of the knurls to bite into and firmly engage tube 15 as indicated at 37 due to the higher hardness of the clevis material. Once the clevis 30 and tube 15 have been properly joined, the plastic shrink wrap 20 can be applied over the tube 15 and an adjacent portion of the clevis 30 and end-cut at recess 380. With reference to Figures 3a and 3b, manually operable actuating means are indicated at 50 which includes an electrically insulating housing 914 having a fixed handle portion 410 integral therewith and a lever portion 420 pivotally engaged to housing 914 at pivot pin 430. Push rod 60 passes through aluminum tube 15 (covered by shrink wrap 20) and engages cross pin 440 at 454; set screw 441 being used to extend into cross pin 440 and set push rod 60 in the cross pin 440. The cross pin 440 is fixedly positioned in lever member 420. Upon pivotal motion of lever arm 420, as indicated at 450, using a conventional hand grip as indicated at 455 to apply pressure to extended handle element 456 of lever member 420, push rod 60 will move linearly as indicated at 460 to actuate an end-effector (not shown in Figure 3a) coupled thereto as hereinabove described. There may be occasions, in the course of certain procedures, that certain surgeons will prefer to hold the actuating means 50 in the manner indicated at 465 with fingers grasping housing 914 and the thumb 467 adjacent a portion 470 of lever member 420 which is positioned on the opposite side of cross-pin 440 from extended handle element 456. Thus, in accord with the the invention, a serrated surface 480 is provided integral with portion 470 of lever member 420 to enable a frictional engagement with thumb 467. Preferably, serrations 480 are provided such that they are transverse the longitudinal axis of the hollow tube 15 and such that they are parallel to the pivot pin 430. Utilizing serrated surface 480, when thumb motion as indicated at 490 is initiated, pivotal motion of lever arm 420 is accomplished, as indicated at 450, as is the linear motion of push rod 60 as indicated at 460. Also seen in Fig. 3a is an insulating ferrule 910 which is designed to extend over and bridge the shrink wrap tubing 20 and the housing 914 so as to guarantee that all portions of the tube 15 are insulated. The ferrule 910 permits a cautery procedure to be accomplished (see cautery terminal 999) without concern of shock to the surgeon. Also, preferably, the ferrule 910 is formed of plastic and is color coded so that a different color is used for each instrument or class of instruments. Thus, for example, scissors may be provided with a red ferrule, while graspers might be provided with a yellow ferrule; clamps with a green ferrule; etc. With reference to Figures 4a and 4b, details are seen of an end effector 40 and the preferred linkage means for linking the end effector 40 to the push rod 60. In particular, in Figs. 4a and 4b, a double acting dissector is shown with blades 90′, 92′ which are respectively rotatably mounted on pivot pin 45 of clevis 30′. Each blade 90′, 92′ of the dissector has a forwardly extending manipulating portion 94, and a rearwardly extending planar base portion 96 with a through-hole 98. Each of the through-holes 98 of planar base portions 96 is separately engaged by a separate connecting or linkage means 110, 112. As shown in Fig. 4a, according to one preferred embodiment, each linkage means 110, 112 is in the form of a thin metal member generally in the shape of an outwardly flared staple. Each linkage means may be generally described as having a U-shaped section 114 with a base 111 perpendicular to and bridging the arms 118 of the U, and two generally parallel spaced apart outwardly extending side or tab elements 113 which are generally parallel to base 111. Each of the linkage means 110, 112 has one of its tab elements 113 engaged in a through-hole 98 of a planar base 96, with the U-shaped section of the linkage means extending respectively in opposite directions as illustrated. The other tab element 113 of the linkage means 110, 112 engage through-holes 120 formed in a flattened plate-like terminal portion 122 of push rod 60. As can be seen from Fig. 4a, movement of push rod 60 in the direction indicated at 124 will cause blades 90′, 92′ to move in the direction indicated at 127 to the position 129 without interference between the oppositely positioned staple-like linkage means 110, 112. That manipulators (blades) 90′ and 92′ open and close in response to the axial movement of push rod 60 may be understood by understanding the relationship of the clevis 30′ and linkage means 110, 112 to the blades 90′, 92′, the push rod 60, and the tube 15. In particular, due to the fact that the clevis 30′ is rigidly attached to the tube 15 (as described above with reference to Fig. 2a), the tube 15 is a fixed distance from the rotation pin 45 of the clevis, and hence to the holes in the blades 90′ and 92′ through which rotation pin 45 extends. Thus, when the push rod 60 is moved axially relative to the tube 15 (the tube being fixed in place), the blades of the end effector cannot move axially with the push rod. However, because the push rod 60 is also a fixed distance away from holes 98 in the base portion of the end effector blades (due to staple linkage means 110, 112), movement of the push rod relative to the tube must cause movement of the holes 98 in the end effector blades. Because one part each blade is fixed, but another part must move when the push rod 60 is moved relative to the tube 15, end effector blades 110 and 112 rotate along an arc centered at the fixed rotation hole in the end effector through which the post 45 of the clevis 30′ extends. Movement in this manner typically effects a cutting or grasping action. The instruments of the invention are preferably assembled in the following fashion. The knurled portion 34 of the clevis 30 of the instrument is inserted into the aluminum tube 15 which had been previously insert molded in the fixed handle portion 914, 410 of the actuating means 50. The aluminum tube 15 is crimped over the knurls 37 to effect mating. Shrink wrap 20 is then applied over the aluminum tube 15 and end-cut at grooves 380 in the arms 36 of the clevis 30. Ferrule 910 is slid over the distal end of the aluminum tube 15, up over the end of the housing 914, and snapped into place, thereby providing complete insulation. The rod 60, staple linkage means 110, 112, and end effectors (e.g. 90, 92) are assembled, with the staples coupling the rod to the end effectors. The rod is slid through the clevis and down the aluminum tube, until the end effectors are located between the arms of the clevis. When the holes in the proximal end of the end effectors (e.g. 96, 98) are lined up with the through-holes 39 in the arms of the clevis, the rotation post 45, which may either be integral with the clevis, or a separate post or nail, is inserted through the holes in the end effectors, and secured in the holes of the clevis arms such as by tapping. At this point, all that remains to be assembled is the actuating means 50. To assemble the actuating means, a cross pin 440 is inserted in handle 420. Handle 420 is then arranged such that the push rod 60 which extends out of the fixed handle portion will extend through the cross pin 440. With rod 60 in the cross pin 440, handle 420 is lined up with handle 410 such that the handle rotation pivot pin 430 can be inserted. With pivot pin 430 in place, and with the end effectors in the closed position, set screw 441 is tightened into the cross pin until it bites into rod 60, thereby holding rod 60 in place relative to cross pin 440. There has been described and illustrated herein endoscopic instruments. While particular embodiments of the invention have been described, it is not intended that the invention be limited exactly thereto. Thus, while particular end effectors were disclosed, it will be appreciated that other end effectors such as, e.g., duck-bill graspers, duck-bill dissectors, atraumatic graspers, and traumatic (rat-tooth) graspers, could be utilized. Also, while various materials were described as being preferred for various parts, it will be appreciated that other materials could be utilized. By way of example only, and not by way of limitation, while the tube and clevis are preferably made from aluminum alloys, with the clevis being harder than the tube, if desired, the tube could be harder than the clevis. In such a situation, rather than crimping the tube over the clevis, the clevis could be welded or press fit into the tube.

Claims: A surgical instrument means (10) for insertion through a trocar tube (80), said surgical instrument means comprising a hollow tube (15) having a longitudinal axis, a reciprocally movable push rod (60) having proximal and distal ends and extending through said hollow tube (15), a pivotally rotatable end effector means (40) coupled to said push rod (60) and mechanically coupled to said outer tube, and an actuating means (50) for imparting reciprocal motion to said push rod (60) relative to said hollow tube (15), said actuating means (50) having a housing means (914) fixedly engaging said hollow tube (15), a lever means (420) with a first handle means (456), the lever means (420) fixedly engaging said push rod (60), and pivot means (430) engaging said lever means (420) and said housing means (914) for pivotally engaging said lever means (420) relative to said housing means (914), said pivot means (430) extending along a second axis transverse to said longitudinal axis, characterized in that said lever means (420) has an external surface having serration means (480) thereon and said actuating means (50) actuates said end effector means (40) upon manipulation of said serrations, and also actuates said end effector means (40) upon manipulation of said first handle means (456). A surgical instrument (10) for insertion through a trocar tube (80) according to claim 1, wherein said serration means (480) extend substantially parallel said pivot means (420). A surgical instrument (10) according to either one of claims 1 and 2 wherein clevis means (30) engages said hollow tube (15) and has a pivot pin (45) extending traverse said longitudinal axis of said hollow tube (15) and said pivotally rotatable end effector means (40) has a hole through which said pivot pin (45) extends. A surgical instrument (10) according to any preceding claim, wherein said housing means (914) comprises a second handle means (410) for receiving at least one finger of a user of said surgical instrument (10) and for cooperating with said lever means (420) to provide pivotal movement of said lever means (420) when said second handle means (410) and said lever means (420) are manipulated by said at least one finger of said user of said surgical instrument (10). A surgical instrument according to claim 4, wherein said serration means (480) is located on said lever means (420) opposite said first handle means (456). A surgical instrument according to any preceding claim, wherein said lever means (420) comprises fixing means extending substantially transverse said longitudinal axis for contacting and fixedly engaging said proximal end of said push rod (60) at a fixing point, and said external surface of said lever means (420) on which said serration means (480) is located is adjacent said fixing point. A surgical instrument according to any preceding claim, wherein said housing means (914) is comprised of plastics, and said housing means (914) is insert moulded with said hollow tube (15) therein.

Inventors: BALES THOMAS O, SLATER CHARLES R, BALES, THOMAS O., SLATER, CHARLES R.
Applicants: SYMBIOSIS CORP, SYMBIOSIS CORPORATION
Application year: 1992
Main classification: A61B17
IPC codes: A61B17, A61B18