Abstract:
A biological forceps device for the taking of tissue samples from a body, comprising a flexible main coil attached at its distal end to a pair of homologous cast jaws. The jaws have radially arranged teeth on their distalmost end. The jaws are opened and closed by attachment to a pair of pull wires which extend through the main coil, into a handle at its proximal end, the handle has a spool which slides about a central shaft attached to the main coil. The spool is attached to the pull wires, so that movement of the spool with respect to the central shaft, effectuates a force on the proximal ends of the levered jaws, to open and close them, appropriately.

Description:
Notice: This is a continuation reissue of application Ser. No.  10 / 074 , 012 , filed Feb.  14 ,  2002 , which is a reissue application of U.S. Pat. No.  6 , 024 , 708 .  
     This is a continuation division of application Ser. No. 08/458,215, filed Jun. 2, 1995, now U.S. Pat. No. 5,666,965 which is a continuation of Ser. No. 07/837,046 filed Feb. 18, 1992, now U.S. Pat. No. 5,507,296, which is a continuation of Ser. No. 07/521,766 filed May. 10, 1990 now U.S. Pat. No. 5,133,727. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to biopsy forceps and more particularly to unique handler actuation wire and homologous jaw construction for those forceps. 
     A number of different types of biopsy forceps are in common use, typically in conjunction with endoscopic assistance. Ordinarily, these devices are of complicated construction, requiring the manufacturing and machining of precise miniaturized components, which are therefore generally quite expensive. 
     One early example of flexible forceps is shown in U.S. Pat. No. 3,895,636 (1975) to Schmidt, wherein a pair of cup shaped jaws having an annular rim mate with a hub and a sharpened trocar. The jaws in this embodiment are of a nature which requires machining for the edge, each jaw being different from the other jaw. 
     U.S. Pat. No. 4,887,612 to Esser et al, shows a similar biopsy forceps which utilizes a cam linkage to effectuate the cup shaped jaws toward and away form one another. The jaws shown in this patent are made from stainless steel and likewise, require expensive machining. 
     U.S. Pat. No. 4,763,668 to Macek et al, shows a biopsy forceps whose cup shaped forceps are driven by a linkage arrangement. Each pivot point in the linkage establishes a new place for stress, wear and breakage. This is similar to the linkage assembly shown in U.S. Pat. No. 4,721,116 to Schintgen et al. A needle between the forceps shown in this patent, is retractable as the forceps close. 
     U.S. Pat. No. 3,921,640 to Freeborn, shows a surgical instrument manufactured from a single piece of molded plastic. The instrument may have any of various forms of jaws including an arrangement of teeth for holding towels or surgical dressing. 
     U.S. Pat. No. 4,200,111 shows a pair of spring biased jaws which are slidably disposed within the end of a trocar. The jaws are moved inwardly and outwardly from the trocar by movement from a twisted wire. 
     U.S. Pat. No. 4,669,471 to Hayashi, shows a biopsy forceps device having a pair of cups attached by a pivot pin, with several linkages between the cups and the operating wire, which are likewise, connected by pivot pins, the pins being welded or fused to their components by the use of laser welding. 
     U.S. Pat. No. 4,815,460 to Porat et al, shows a medical device for gripping, having a pair of jaws which are identical to one another. The jaws have an array of teeth disposed completely thereacross. The teeth are divided longitudinally across each jaw and are out of phase from one another by a half a pitch. The instrument is utilized for gripping purposes. A further device is shown in U.S. Pat. No. 825,829 to Heath. This appliance utilizes two different sets of engaging jaws to accomplish its cutting purpose. 
     It is an object of the present invention to provide a forcep device which overcomes the disadvantages of the prior art. 
     It is a further object of the present invention to provide a cutting device having a pair of jaws, wherein each jaw may be a duplicate of its opposing jaw. 
     It is yet a further object of the present invention to provide a cutting device which is self-aligning which permits greater tolerance in the dimensions of the components in their manufacture. 
     SUMMARY OF THE INVENTION 
     The present invention comprises an improvement in biopsy forceps wherein a pair of jaws are formed from a casting. Each jaw of the pair of jaws of the biopsy forceps may be a duplicate of the other jaw. Each jaw is somewhat hemispherically shaped having an elongated portion which extends proximally into a cutter tang. Each cutter jaw has a generally U-shaped distalmost end on which is defined a plurality of radially disposed teeth. The teeth on one side of the longitudinal centerline of the jaw are displaced by one-half pitch from the corresponding teeth on the other side of the longitudinal centerline on that jaw. The displacement by one-half pitch of the teeth on one side of the jaw relative to those corresponding teeth on the other longitudinal side of the jaw permits the same casting to be used for both the upper and lower jaws. The radially disposed array of teeth on each of the jaws permits a self-aligning feature therewith, thus compensating for the slightly looser tolerances found in the casting manufacturing technique. 
     Each jaw extends proximally and terminates in a tang, as aforementioned. Each tang is arranged so as to receive a joggled pull wire therethrough. Each jaw is mated with one another about a clevis pin which is cast unitarily with a clevis. The clevis extends into a housing which is crimped to a main coil, the proximal end of which extends into a handle having means for articulating the jaws. Each joggled pullwire from the tang on the proximal end of each jaw flexibly extends through the main coil and into the hub of the handle at the proximal end of the forceps assembly. 
     The handle comprises a central shaft about which a displaceable spool is disposed. The central shaft has a longitudinally directed stepped diameter bore extending therein on its distal end, and a thumb ring on its proximalmost end. The proximal end of the coil extends into the bore on the proximal end of the central shaft. The bore in the central shaft on the handle has a stepped configuration. The distal end of the bore having a slightly larger diameter than the second or intermediate bore, or the third or proximal end of the bore in the central shaft. A locking coil is arranged to mate within the stepped large outer diameter (distal end) of the central shaft. The locking coil has an inner diameter which is slightly smaller than the outer diameter of the main coil extending from the cutter jaw assembly to the handle. The main coil is screwed into the locking coil disposed within the central shaft. A sheath which acts as a strain relief, is disposed distally of the locking coil about the main coil within the central shaft. The sheath holds the locking coil within the first stepped bore in the central shaft. The strain relief is bonded to the bore of the central shaft. The proximalmost end of the joggled pull wires extend through the proximal end of the main coil and into a thin anti-kink tube in the narrowest third stepped bore in the central shaft. The cross pin fits through a slot at the midpoint of the central shaft. The slot is in communication with the third bore therein. A cross pin mates with the slot across the central shaft. The proximalmost end of the joggled pull wires are locked into an opening in the cross pin. The ends of the cross pin mate with slots in the spool so as to facilitate corresponding motion in the joggled pull wires. 
     Proximal movement of the spool with respect to the central shaft effectuates a pull on the joggled pull wires so as to create a pivotable motion of the tangs on the proximal end of the cutters, to cause the cutter jaws to engage to one another. 
     Movement of the spool distally with respect to the central shaft effectuates a compression on the pull wire thus causing arcuate movement of the tangs on the proximal end of each jaw to force a pivoting motion about the clevis pin thus opening the respective jaws. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and advantages of the present invention will become more apparent when viewed in conjunction with the following drawings, in which: 
         FIG. 1  is a side elevational view in section, of a biopsy forceps assembly; 
         FIG. 2  is a side assembly view of the distalmost end of a biopsy forceps assembly with a needle, with its cutter jaws being opened; 
         FIG. 3  is a plan view, partly in section, of the distal end of a biopsy forceps without a needle; 
         FIG. 4  is a side elevational view partly in section of the biopsy forceps shown in  FIG. 3  with its jaws opened; 
         FIG. 5  is a plan view, partly in section, of the distal end of a biopsy forceps assembly, with a needle; 
         FIG. 6  is a side elevational view partly in section, of the biopsy forceps shown in  FIG. 5 ; and 
         FIG. 7  is a side elevational view in section, showing part of the handle at the proximalmost end of a biopsy forceps assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings in detail and particularly to  FIG. 1 , there is shown a biopsy forceps assembly  10 , having a distal end  12 , comprising a jaw assembly  14 , and a proximal end  16  comprising a handle  17 , spool  19  and thumb ring  21  for manipulation of the assembly. The jaw assembly  14  comprises a pair of jaws  18 , each of which is a duplicate of the other. Each jaw  18  as may be seen in  FIGS. 2 and 3 , is a generally elongated somewhat hemispherically shaped structure having a distalmost end and a proximalmost end. Each jaw  18  has on its distalmost end, an array of teeth  20  generally radially directed about a point “R”, as exemplified in FIG.  3 . Each jaw  18  has a generally longitudinal centerline as may be seen in  FIGS. 3 and 5 . The teeth  20  on one side of the longitudinal centerline of each jaw  18  being displaced by one half pitch from the corresponding teeth  20  on the other side of the longitudinal centerline on that jaw  18 . The displacement by one half pitch by the teeth on one side of the jaw  18  is relative to those corresponding teeth  20  on the other longitudinal side of the jaw  18  permits the same casting to be used for both the upper and lower jaws of the jaw assembly  14 . The radial arrangement of the teeth  20  as best seen in  FIGS. 3 and 5  require each jaw  18  when they close onto one another to automatically mate and effectuate proper alignment therebetween. The self-alignment permits each jaw  18  to be manufactured by an investment casting technique which is inheritantly less expensive than the typical prior art jaws which are machined and which distalmost teeth are either non-existant or they are transverse to the longitudinal centerline the jaws, which jaws inheritantly fail to have any positive cutting edge at their distalmost ends. The casting of each jaw  18  also permits a looser tolerance therebetween which is characteristic of the casting manufacturing technique without any loss in effectiveness of those jaws. 
     Each jaw  18  has a proximalmost end which comprises a tang  24 . Each tang  24  has a generally semicircular recess position  26  on its outer side thereof. The recessed portion  26  may be seen most clearly in  FIGS. 3 and 5 , and then a side view in  FIGS. 2 ,  4  and  6 . A bore  30  extends tranversely through the midpoint between the distal end proximalmost ends of each jaw  18 . Each jaw  18  is mated with one another and so as to each be levered about a clevis pin  28  which extends through the bore  30  on each respective jaw  18 . Each jaw  18  has an annular bore  33  disposed about the outer face of its bore  30 , as shown in  FIGS. 3 and 5 . The boss  33  acts as a bearing surface to reduce the typical friction found on prior art forceps. The clevis pin  28  is received in a hole  32  in clevis  34  as shown in  FIGS. 3 and 5 . The clevis  34  extends proximally, as shown in  FIGS. 2-6 , into a hub  40 . The clevis  34 , the housing  40  and clevis pin  28  are made from a common casting. The clevis pin  28  unitarily extending from one of the sidearms  29  Of the clevis  34 . 
     A main tubular coil  50  shown in  FIG. 2  at its distal end thereof, has a portion of it periphery ground flat, as at  52 . The flattened distal periphery of the main coil  50  permits a more solid anchoring between the inside of the hub  40  and the distal end of the main coil  50  when the two are crimped together, obviating the need for adhesives, soldering or welding. 
     An FEP sheath  54  extends from the distal end of the main coil  50  therethrough into the central shaft  56  of the handle  17  as shown in  FIGS. 2 and 7 . This sheath  54  acts as a bearing between a pair of pull wires  60  and the lumen of the main coil  50 . 
     The distalmost end of each pull wire  60  has a Z-bend therein. the Z-bend of each pull wire  60  has a first portion  62  which is rotatably disposed in the recess  26  in the tang  24  of each cutter jaw  18 . The Z-bend has a second portion  64  which extends through a bore  66  in the proximalmost end of the tang  24 , as best shown in  FIGS. 3 and 5 . A ninety degree bend  68  between the second portion  64  and the main pull wire  60  eliminates the pinching common to prior art loop design wires. Each pull wire  60  has a reflex curve  70  as shown in  FIG. 2  as well as in  FIGS. 6 and 7 , extending between their distalmost ends and the distalmost end of the main coil  50 . The reflex curve  70  helps to open the cutter jaws  18  when the spool  19  on the handle  17  is displaced distally thereto. 
       FIGS. 2 ,  5  and  6  shows the distal end of the biopsy forceps assembly  10  with a flat needle  80  disposed between the two cutter jaws  18 . The needle  80  has a pointed distalmost end  82  that terminates just within the cutter jaws  18  when closed, and has tail  84  comprising its proximalmost end which extends within the distalmost end of the main coil  50 . The needle  80  has a central opening through which the clevis pin  28  may extend as shown in  FIGS. 3 and 5 . The needle  80  is flat, and as such may be disposed between the two tangs  24  of each cutter jaw  18  as shown in FIG.  5 . In cutter jaw assembly  14  without the needle therein, a washer  90  is disposed between the two cutter jaws  18  on the clevis pin  28 . 
     The proximal end of the main coil  50  and the proximal end of the pull wires  60  extend into handle  17  at the proximal end  16  of the biopsy forceps assembly  10 . The handle  17  comprises a central shaft about which a displaceable spool  19  is disposed. The central shaft has a longitudinally directed stepped diameter bore  92  extending therein, as shown in  FIGS. 1 and 7 . The proximal end of the main coil  50  extends into the bore  92  on the proximal end of the central shaft. The bore  92  extending into the central shaft has a three stepped configuration. The bore  92  on the distalmost end of the central shaft has a large first diameter  94  as shown in  FIG. 7  which steps to a smaller second diameter  96  which subsequently steps down to a smaller yet third diameter bore  98 . A locking coil  100  is disposed against the first largest diameter bore  94  in the central shaft. The main coil  50  has an outer diameter slightly larger than the inner diameter of the locking coil  100  and is threadedly received therethrough. The main coil  50  thus extends to and abuts the handle  17  adjacent the second stepped bore  96  of the bore  92  in the central shaft. The pull wires  60  disposed through the inner lumen of the main coil extend therethrough and into the smallest portion  98  of the bore  92  in the central shaft. A strain relief sheath  102  is disposed distally to the locking coil about the main coil  50  within the largest bore  94  in the central shaft. The strain relief sheath  102  extends slightly distally of the distalmost end of the central shaft, and is bonded to the inner walls of the largest bore  94  by a solvent which is directed thereto through a hole  104 , as shown in FIG.  7 . The strain relief sheath  102  limits twist and movement of the main coil  50  with the bore  94  while preventing a sharp bend of the coil  50  at the distal end of the handle  17 . The proximalmost end of the pull wires  60  extend through the proximal end of the main coil  50  as aforementioned and through and anti-kicking tube  109 , and are locked into a cross pin  110 , as shown in  FIG. 1 , which cross pin  110  mates with a slot  112  disposed across the central shaft of the handle  17 . The slot  112  is in communication with the axial bore  92  in the central shaft. The proximalmost end of the pull wires  60  are locked into the cross pin  110  by a set screw  114  as shown in FIG.  1 . The ends of the cross pins  110  mate with a slot  116  in the spool so as to lock the cross pin  110  therewith. Movement of the spool  19  which is disposed about the central shaft thereby effectuates movement of the puller wires  60  disposed within the main coil  50 , the distal ends of which are attached to the tangs  24  on the cutter jaws  18  as shown in  FIGS. 1 and 2 . 
     Thus there has been shown a biopsy forceps assembly which can be made in a very cost effective manner for an improved biopsy sample. The cutter jaws and clevis support of the biopsy forceps each being made of a cast material permitting a far less expensive manufacture because of its simplicity permitting one jaw design and its self-aligning radially directed distal jaw teeth effectuating its cutting effectiveness as well as its ease of assembly. The pull wire arrangement with each particular jaw eliminates the prior art multiple linkages which have frictional problems and potential for breakage therewith. The spool design for the grasping of the pull wires in regard to the handle therewithin facilitates a one-handed operation thus permitting the physician use of his other hand for other purposes.