Abstract:
A jaw assembly for an endoscopic bioptome includes a pair of opposed end effectors having resilient arms formed from a super-elastic metal. The distal ends of the resilient arms terminate in end effector jaw cups which are also preferably formed from super-elastic metal, while the proximal portions of the resilient arms include angled portions which urge the jaw cups away from each other. The jaw cups are brought together into a biting action by a cylinder having a sharp distal edge which moves relative to and over he arms of the end effectors. As the resilient arms are formed from a super-elastic metal, they exhibit very high resiliency and durability even after numerous uses.

Description:
This is a 371 of Int&#39;l Application Serial No. PCT/US96/06924 filed May 10, 1996, now Int&#39;l Publication No. WO 96/35374, which is a continuation of U.S. application Ser. No. 08/440,326 filed May 12, 1995, now U.S. Pat. No. 5,638,827, which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to endoscopic surgical instruments. More particularly, this invention relates to super-elastic jaw assemblies for multiple sample endoscopic instruments. 
     STATE OF THE ART 
     Endoscopic biopsy procedures are typically performed with an endoscope and an endoscopic biopsy forceps device (bioptome). The endoscope is a long flexible tube carrying fiber optics and having a narrow lumen through which the bioptome is inserted. The bioptome typically includes a long flexible coil having a pair of opposed jaws at the distal end and manual actuation means at the proximal end. Manipulation of the actuation means opens and closes the jaws. During a biopsy tissue sampling operation the surgeon guides the endoscope to the biopsy site while viewing the biopsy site through the fiber optics of the endoscope. The bioptome is inserted through the narrow lumen of the endoscope until the opposed jaws arrive at the biopsy site. While viewing the biopsy site through the fiber optics of the endoscope, the surgeon positions the jaws around a tissue to be sampled and manipulates the actuation means so that the jaws close around the tissue. A sample of the tissue is then cut and/or torn away from the biopsy site while it is trapped between the jaws of the bioptome. Keeping the jaws closed, the surgeon withdraws the bioptome from the endoscope and then opens the jaws to collect the biopsy tissue sample. 
     A biopsy tissue sampling procedure often requires the taking of several tissue samples either from the same or from different biopsy sites. Unfortunately, most bioptomes are limited to taking a single tissue sample, after which the device must be withdrawn from the endoscope and the tissue collected before the device can be used again to take a second tissue sample. The single-sample limitation of most bioptomes is due to the limited space between the biopsy forceps jaws. Several attempts have been made to provide an instrument which will allow the taking of several tissue samples before the instrument must be withdrawn and the samples collected. Problems in providing such an instrument include the extremely small size required by the narrow lumen of the endoscope and the fact that the instrument must be flexible in order to be inserted through the lumen of the endoscope. Thus, several known multiple sample biopsy instruments are precluded from use with an endoscope because of their size and rigidity. These include the “punch and suction type” instruments disclosed in U.S. Pat Nos. 3,989,033 to Halpern et al. and 4,522,206 to Whipple et al. Both of these devices have a hollow tube with a punch at the distal end and a vacuum source coupled to the proximal end. A tissue sample is cut with the punch and suctioned away from the biopsy site through the hollow tube. It is generally recognized, however, that suctioning tissue samples through a long narrow flexible bioptome is virtually impossible. 
     Copending application U.S. Ser. No. 08/189,937 discloses an endoscopic multiple sample bioptome which allows for the taking of multiple samples before removal of the bioptome from the endoscope. The multiple sample bioptome includes a hollow outer member and an axially displaceable inner member extending therethrough. The proximal ends of the outer and inner members are coupled to an actuator for axially displacing one relative to the other. The distal end of the outer member is coupled to one of a cylinder having a sharp distal edge and a jaw assembly, while the distal end of the inner member is coupled to the other. The jaw assembly includes a pair of opposed, preferably toothed jaw cups each of which is coupled by a resilient arm to a base member. The arms are bent to urge the jaws away from each other. The base member is mounted inside the cylinder and axial movement of the jaw assembly and cylinder relative to each other draws the arms into the cylinder (or extends the cylinder over the arms) and brings the jaw cups together in a biting action. In this manner, multiple samples from a patient can be taken and stored within the jaw assembly before needing to retrieve the bioptome from the patient. 
     A family of alloys known to exhibit unusual elasticity and flexibility properties has recently been identified as having useful practical applications. These alloys specifically exhibit what is called the shape memory effect. This effect provides that if such an alloy is plastically deformed from its original shape at one temperature, it will completely recover its original shape on being raised to a higher temperature. In recovering their shapes these alloys can produce a displacement or a force, or a combination, as a function of the temperature. Due to the unique atomic structure necessary for the memory shape effect to take place, these alloys exhibit other properties as well, such as super-elasticity or pseudo-elasticity. 
     The type of transformation which occurs in the shape memory alloys is known as a martensitic transformation and changes the material from a high temperature form, called austenite, to a low temperature form called martensite. For a given shape memory alloy, the transformation between martensite form and austenite form occurs at a predictable temperature, known as the transformation temperature. 
     In order for an alloy to exhibit the shape-memory effect, it must first be bent into the shape to be “memorized” at room temperature. The alloy is then heated until it assumes a high-temperature configuration called the beta or parent phase, where the crystal structure of the metal assumes its austenite form which it will “remember”. Next, the alloy is rapidly cooled so that the atoms in the alloy rearrange themselves into the crystal form of martensite. The alloy may then be bent into a new shape which it will maintain as long as the temperature remains below the transformation temperature. If the alloy is subsequently reheated above its transformation temperature so that the alloy structure reverts to an austenite form, it will recover its previously memorized shape. Shape memory alloys exhibit significantly increased resiliency relative to their non-superelastic counterparts, because the atoms of the memory metal shift back and forth between martensite and austenite forms, and do not slip into new dislocated configurations as is the case with normal metals. 
     Useful temperature independent properties are also exhibited by memory-shape alloys. In an alloy that has a beta phase capable of producing martensite under stress, one can observe an unusual elastic property called super-elasticity or pseudo-elasticity. In a typical alloy with this property, the metal exhibits normal elastic behavior under stress (that is, it gets longer in some dimensions) until the critical stress is reached at which point martensite molecular structures begin to form. With further stress, the specimen continues to elongate, as if it were being plastically deformed. When the stress is removed, the martensite structure reverts to the parent phase, or austenite structure, and the metal contracts to its original dimensions, showing no permanent deformation. 
     Presently, the applications of shape memory materials in medical apparatuses are very limited. U.S. Pat. No. 4,925,445 to Sakamoto et al. discloses a guide wire for a catheter, where the guide wire has a rigid body and a flexible distal end made of a memory-shape metal alloy with the super-elastic properties described above. The distal end of the wire is curved back such that a blunt forward tip is formed. With a super-elastic distal end, the guide wire can be guided through the blood vessel of a patient without the risk of permanently deforming the tip of the wire, which could result in the tearing of the blood vessel walls or in the misguiding of the wire. U.S. Pat. No. 5,254,130 to Poncet et al., similarly uses a memory-shaped alloy as a push rod and steering means for steering a distal clevis and attached end effectors. As the push rod is extended outside of the housing where it is held prior to deployment, the push rod assumes a remembered configuration relative to the straight housing, and hence steers the end effectors to a desired position. Other than the steering functions disclosed in the Sakamoto et al. and Poncet et al. patents, however, the super-elasticity of shape memory alloys has not been used in medical apparatus of the art. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a jaw assembly for a bioptome where at least portions of the jaw assembly are made out of a superelastic metal. 
     It is another object of the invention to provide a jaw assembly for an endoscopic multiple sample bioptome where the jaw arms are superelastic and flexible and repeatedly return to desired positions without fracturing or deforming. 
     It is a further object of the invention to provide a jaw assembly for an endoscopic multiple sample bioptome where the arms of the jaw assembly undergo insignificant plastic deformation even after repeatedly being opened and forced closed. 
     It is also an object of the invention to provide a jaw assembly for an endoscopic multiple sample bioptome which is simple to assemble. 
     In accord with these objects which will be discussed in detail below, an endoscopic bioptome is provided with a jaw assembly, a tubular member, and an axially displaceable wire extending through the tube member, where the distal end of the wire and tubular member are both coupled to the jaw assembly, and the jaw assembly includes a pair of opposed end effectors having resilient arms formed from a superelastic metal. According to a first embodiment of the invention, the proximal ends of the resilient arms include angled portions, while the distal ends terminate with end effector jaw cups, which are also preferably formed from a superelastic metal. The resilient arms urge the jaw cups away from each other. As the resilient arms are formed from a superelastic alloy, they exhibit very high resiliency and durability even after numerous uses. Other embodiments of the jaw assembly include arms having mounting holes and cups having radially arranged teeth and closing cams. Another embodiment of the jaw assembly includes arms having proximal semi-cylindrical portions with distally extending tabs. Different types of mounting screws are provided for coupling the proximal ends of the arms of the jaws to the distal end of the tubular member. 
     According to preferred aspects of the invention, the tubular member is a flexible coil, and the proximal portion of each arm is mounted inside the distal end of the tubular member by means of a threaded screw and washer (or retaining sleeve) threaded in the coil. The distal end of the wire is coupled to a cylinder which is preferably provided with a knife sharp distal edge. Different embodiments for coupling the distal end of the wire to the cylinder are disclosed. The proximal ends of the coil and wire are coupled to a manual actuation means for axially displacing one of the coil and wire relative to the other. Axial movement of the wire relative to the coil moves the cylinder over the arms of the end effectors and over the necks of the jaw cups, thereby forcing the jaw cups together in a biting action. 
     According to another embodiment of the invention, a laparoscopic type multiple sample bioptome is provided with the super-elastic jaw assembly of the invention. The laparoscopic type bioptome is provided with a relatively rigid hollow tube, and a relatively rigid rod which extends therethrough. The distal end of the rod is coupled to the jaw assembly described in the first embodiment, and the distal end of the tube is provided with a knife-sharp edge similar to the cylinder edge described above. The proximal end of the rod is coupled to a fixed portion of a handle and the proximal end of the tube is coupled to a movable lever portion of the handle. Movement of the lever of the handle results in longitudinal movement of the tube relative to the rod and effects and closing of the jaws as described above. 
     Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view in partial section of the proximal end of a first embodiment of the invention; 
     FIG. 1 a  is a plan view of one hermaphroditic part of a two part spool according to a preferred embodiment of the invention; 
     FIG. 1 b  is a side elevation view of the one part of the two part spool; 
     FIG. 1 c  is a proximal end view of the one part of the two part spool; 
     FIG. 1 d  is a distal end view of the one part of the two part spool; 
     FIG. 1 e  is a broken schematic section illustrating a leaf spring locking of two parts of the two part spool; 
     FIG. 2 is an enlarged transparent side elevation view of the distal end of a first embodiment of the invention with the jaws open; 
     FIG. 3 is an enlarged exploded side view of the distal end of a first embodiment of the invention; 
     FIGS. 4 a  and  4   b  are respectively a front view of the threaded screw and a front view of the washer of FIG. 3; 
     FIG. 4 c  is a cross sectional view taken along line C—C of the arms of the jaw assembly shown in FIG. 3; 
     FIG. 5 is an enlarged transparent side elevation view of the distal end of a first embodiment of the invention with the jaws closed; 
     FIG. 6 is an enlarged transparent top elevation view of the distal end of a first embodiment of the invention; 
     FIGS. 7 a  through  7   e  are enlarged transparent side elevational views of the distal end of the first embodiment, showing a sequence of biopsy sampling operations; 
     FIGS. 7 f  through  7   h  are views similar to FIG. 6 showing the cutting action of the knife-sharp distal edge of the cylinder; 
     FIG. 8 a  is an enlarged broken side elevation view of a different embodiment of control wire coupling; 
     FIG. 8 b  is a cross sectional view along line B—B in FIG. 10 a;    
     FIG. 9 a  is a view similar to FIG. 8 a  but of yet another embodiment of control wire coupling; 
     FIG. 9 b  is a cross sectional view along line B—B of FIG. 9 a;    
     FIG. 10 is a broken side elevation view in partial section of a second embodiment of the invention; 
     FIG. 10 a  is an enlarged transparent side elevation view of the jaw assembly to push rod and outer tube coupling of the second embodiment of the invention of FIG. 10 with the jaws open; 
     FIG. 11 is an exploded perspective view of another embodiment for mounting jaws on the distal end of a coil; 
     FIG. 11 a  is a sectional view taken along the line  11   a — 11   a  in FIG. 11; 
     FIG. 11 b  is a view similar to FIG. 11 with the jaws coupled to the distal end of the coil; 
     FIG. 12 is an enlarged exploded side elevation view of another embodiment for mounting jaws on the distal end of a coil; 
     FIG. 12 a  is a broken perspective view of a jaw arm according to the embodiment of FIG. 12; 
     FIG. 12 b  is broken side elevation view of the embodiment of FIG. 12 in a partially assembled state; 
     FIG. 12 c  is a sectional view taken along line  12   c — 12   c  in FIG. 12 b;    
     FIG. 13 is an exploded side elevation view of a presently preferred embodiment for mounting jaws on the distal end of a coil; 
     FIG. 13 a  is and enlarges distal end view of the screw in FIG. 13; 
     FIG. 13 b  is a reduced, partially transparent, side elevation view of the embodiment of FIG. 13 as assembled prior to attachment to the distal end of a coil; 
     FIG. 14 is an enlarged side elevation view of another embodiment for coupling a cylindrical sleeve to the distal end of a control wire; 
     FIG. 14 a  is a top view of the embodiment of FIG. 13; and 
     FIG. 14 b  is an enlarged sectional view taken along lines  13   b — 13   b  of FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 through 6, a first embodiment of the multiple sample bioptome with the super-elastic flexible jaw assembly is shown and includes a proximal handle portion  12  and a distal end effector portion  14 . A long flexible coil  16 , and an axially displaceable control wire  18  which extends through the coil  16  couples the handle portion  12  to the end effector portion  14 . The coil  16  is preferably covered with a PTFE, FEP or polyolefin sheath  15  along substantially all of its length and a strain relief sleeve  17  covering a portion of the coil which extends from the handle  12 . The coil  16 , by its nature is effectively internally threaded and can receive a screw with mating threads as discussed in further detail below at its open distal end  16   a  which is preferably ground flat  16   b.  The control wire  18  is preferably flexible but longitudinally inelastic and is ideally formed from 304 Steel and provided with an outer diameter of approximately 0.017-0.018 inch. The proximal handle portion  12  includes a central shaft  20  and a displaceable spool  22 . The proximal end of the shaft  20  is provided with a thumb ring  24  and a longitudinal bore  26  is provided at the distal end of the shaft  20 . A longitudinal slot  28  extends from the proximal end of bore  26  to a point distal of the thumb ring  24 . The displaceable spool  22  is provided with a cross member  30  which passes through the slot  28  in the central shaft  20 . The cross member  30  is provided with a central through hole  32  and a radially engaging set screw  34 . According to the first embodiment of the invention, a short bore  36  and a radially engaging set screw  38  are provided in the shaft  20  distal of the thumb ring  24  with the bore  36  communicating with the longitudinal slot  28 . In the first embodiment of the invention, the proximal end of the coil  16  extends into the central through hole  32  in the cross member  30  and is fixed there by the set screw  34 . The proximal end of the control wire  18 , passes through slot  28 , is inserted into the short bore  36 , and held there by the set screw  38 . From the foregoing, those skilled in the art will appreciate that relative movement of the shaft  20  and spool  22  results in movement of the control wire  18  relative to the coil  16 . Such action results in actuation of the end effectors as described in detail below. 
     According to a preferred embodiment of the invention, an hermaphroditic two part snap-together spool is used. FIGS. 1 a  through  1   e  illustrate the principal features of each part  222   a  ( 222   b ) of a snap together spool. Two identical hermaphroditic parts  222   a  ( 222   b ) each represent one half of the spool. Each part  222   a  ( 222   b ) is substantially semi-cylindrical with a spool shaped outer profile. A coil engaging member  224   a  ( 224   b ) extends radially inward within a semi-cylindrical recess  226   a  ( 226   b ) which extends the entire length of the part  222   a  ( 222   b ). Each part  222   a  ( 222   b ) is provided with a pair of diametrically opposed locking tabs  228   a  ( 228   b ),  230   a  ( 230   b ) and a pair of diametrically opposed tab receiving slots  232   a  ( 232   b ),  234   a  ( 234   b ). In addition, each part  222   a  ( 222   b ) is provided with a pair of diametrically opposed guide pins  236   a  ( 236   b ),  238   a  ( 238   b ) and a pair of diametrically opposed pin receiving holes  240   a  ( 240   b ),  242   a  ( 242   b ). From the foregoing, it will be appreciated that when the two parts  222   a ,  222   b  are assembled, the guide pins  236   a ,  238   a  on part  222   a  enter the pin receiving holes  240   b,    242   b , respectively, on part  222   b ; and the locking tabs  228   a ,  230   a  on part  222   a  enter the tab receiving slots  232   b ,  234   b,  respectively, on part  222   b . Similarly, the guide pins  236   b,    238   b  on part  222   b  enter the pin receiving holes  240   a ,  242   a , respectively, on part  222   a;  and the locking tabs  228   b ,  230   b  on part  222   b  enter the tab receiving slots  232   a ,  234   a,  respectively, on part  222   a.  Prior to the snapping the parts together, the proximal end of the coil  16  (FIG. 1) with a crimp band (not shown) on its end, is placed between the coil engaging members  224   a ,  224   b . When the parts  222   a ,  222   b  are assembled the respective coil engaging members  224   a ,  224   b  hold the proximal end of the coil securely. 
     According to a preferred aspect of the two part spool, the tab receiving slots are provided with leaf springs to inhibit the two parts from coming apart. FIG. 1 e  illustrates the leaf spring schematically with reference to the tab  228   a  on part  222   a  as it engages the slot  232   b  on part  222   b . As seen in FIG. 1 e,  the slot  232   b  is partially occluded by a depending arm  233   b  which acts like a leaf spring when it is engaged by the tab  228   a  as it enters the slot  232   b . After the tab  228   a  enters the slot  232   b , the arm  233   b  will prevent the tab  228   a  from rising out of the slot  232   b.    
     Turning now to FIGS. 2 through 6, the end effector portion  14  includes a cylindrical sleeve  40 , preferably having a knife-sharp distal edge  42 , and a jaw assembly  44 . The jaw assembly  44  includes a pair of end effectors  44   a ,  44   b , a screw  102 , and a washer or retaining sleeve  104 . Each end effector  44   a ,  44   b  includes a jaw cup  46   a ,  46   b  preferably having a knife-sharp rim  48   a ,  48   b  (or radially arranged teeth as described in detail below), and a resilient, preferably narrow, arm  50   a ,  50   b  which extends proximally from the jaw cup  46   a ,  46   b.  The narrow arm  50   a ,  50   b,  at its proximal end  51   a,    51   b,  preferably includes a sharply descending angled portion  52   a ,  52   b , and a gently angled portion  53   a ,  53   b.  At least the gently angled portion  53   a ,  53   b  of the arms  50   a ,  50   b,  and preferably the entire arms  50   a ,  50   b  are formed from super-elastic memory metal such as Nitinol (nickel-titanium alloy), and are biased apart from each other (due to angled portions  53   a ,  53   b  of the arms  50   a ,  50   b ), thereby urging the jaw cups  46   a ,  46   b  apart (as seen in FIG.  2 ). In addition, as the arms  50   a ,  50   b  and the jaws  46   a ,  46   b  are preferably integral with each other, the jaws are preferably formed from a super-elastic or shape metal. However, it should be appreciated that while it is preferable to form the entire arm and jaw from a super-elastic or shape memory metal, the jaw cups  46   a ,  46   b  and proximal ends  51   a-b,    51   a-b  of the jaws  44  may be made of any other material and attached to the resilient arms  50   a ,  50   b  by any conventional and appropriate means. 
     According to the first embodiment of the invention, the proximal end  51   a,    51   b  of each arm  50   a ,  50   b  is coupled to the distal end  16   a  of the coil  16  by crimping/locking with a hollow threaded screw  102  and a washer  104  as best illustrated in FIGS. 3 and 4. The threaded screw  102  is substantially cylindrical, and generally includes a head portion  106 , a threaded portion  108 , and a cylindrical throughbore  110  along its central axis. The throughbore  110  is dimensioned to receive and allow lateral movement of the control wire  18 . The distal end  112  of the head portion  106  has a diameter substantially equal to that of the outer diameter of the coil  16 , and is provided with two opposing grooves  114   a ,  114   b  (see FIG. 4 a ) on the outer perimeter of the distal end  112  of the head portion  106 . Grooves  114   a ,  114   b  are dimensioned to receive the angled portion  52   a ,  52   b  at the proximal end  51   a ,  51   b  of each of the narrow arms  50   a ,  50   b.  The proximal end  116  of the head portion  106  is shaped as a truncated cone (i.e., frustroconical) and has a larger diameter  118   b  at the distal end  112  of the head portion  106  and a smaller diameter  118   a  at the distal end  120  of the threaded portion  108 . The threaded portion  108  has a diameter substantially equal to the inner diameter of the coil  16  and the proximal end  122  of the threaded portion  108  includes threads  124  for lockingly engaging the interior of the distal end  16   a  of the coil  16 . 
     The washer  104  is substantially cylindrical, and generally includes a throughbore  126  having proximal  128  and distal  130  sections. The distal section  128  of the throughbore  126  is shaped as a truncated cone, and the proximal section  130  extends therefrom. It will be appreciated that the throughbore  126  of the washer  104  has substantially the same configuration as the proximal end  116  of the head portion  106  of the screw  102  and distal end  120  of the threaded portion  108  of the screw  102 . It will now be understood that the throughbore  126  of the washer  104  is dimensioned for engaging the proximal end  116  of the head portion  106  of the screw  102  and distal end  125  of the threaded portion  108  of the screw  102  when the stepped  52   a ,  52   b  proximal ends  51   a,    51   b  of the narrow arms  50   a ,  50   b  are positioned about the grooves  114   a-b  of the threaded screw  102  as described above. The proximal end  120  of the threaded portion  108  of the threaded screw  102  is then threaded into the interior of the distal end  16   a  of the coil  16 . As can be seen in FIGS. 2 and 3, the washer  104  is fastened between the head portion  106  of the threaded screw  102  and the distal end  16   a  of the coil  16 . The stepped  52   a ,  52   b  proximal ends  51   a ,  51   b  of the narrow arms  50   a ,  50   b  are thus fastened between the washer  104  and the threaded screw  102 . 
     As can be seen in FIG. 4 c,  the preferred end effector arms  50   a ,  50   b  have a substantially arced shape in cross section with inner and outer curved walls  55   a ,  55   b ,  56   a ,  56   b.  It will be appreciated that the arced shape of the arms extends the length of the narrow arms from the jaws  44   a ,  44   b , back to the angled proximal portions  52   a ,  52   b . With this arrangement, the tube  40  will slide easily over the arms as will be described hereinafter. In addition, the angled proximal portions  52   a ,  52   b  of the jaws  44   a ,  44   b  matingly engage the grooves  114   a ,  114   b  (see FIG. 4 a ) on the outer perimeter of the distal end  112  of the threaded screw  102  head portion  106 . 
     Referring to FIGS. 2,  5  and  6 , it will be seen that the cylindrical sleeve  40  is coupled to the distal end of the control wire  18  by providing the sleeve  40  with a lateral hole  45  which engages a bent end  18   a  of the control wire  18 . As illustrated, the bent end  18   a  of the control wire  18  is welded to the hole  45  in the side of the sleeve  40 . However, as will be described in detail hereinbelow, other methods of coupling the control wire to the sleeve are possible. The cylindrical sleeve  40  is slidably mounted over the cylindrical washer  104  and head portion  106  of the threaded screw  102 , and is axially movable over the arced resilient arms  50   a ,  50   b,  thereby bending the arms at the gently bent locations  53   a ,  53   b,  and closing the jaws  46   a ,  46   b  as shown in FIG.  5 . As the resilient arms  50   a ,  50   b  are made of superelastic metal, they will immediately return to their original open position (FIG. 2) once the cylinder sleeve  40  is retracted. Furthermore, even after repeatedly sliding the cylinder sleeve  40  back and forth over the arms  50   a ,  50   b,  the jaw assembly  44  will maintain its original shape due to the above described properties of the superelastic metal. 
     As seen in FIG. 6, the jaw cups  46   a ,  46   b  have an eccentric, albeit symmetrical outline with their widest point indicated by the line  47 . Distal of the line  47 , the jaw cups are substantially hemispherical and proximal of the line  47 , the jaw cups are substantially hemi-elliptical. The jaw cups are arranged so that the rims are substantially aligned when closed as shown in FIG.  5 . It will also be seen from FIGS. 5 and 6 that the side walls  57 ,  57   b ,  59   a ,  59   b  of the jaw cups  46   a ,  46   b  taper towards the arms  50   a ,  50   b  to provide a smooth transition from the jaw cups to the arms. 
     From the foregoing description and with reference to FIGS. 1 through 6, those skilled in the art will appreciate that when the spool  22  and the shaft  20  are axially displaced relative to each other, the cylindrical sleeve  40  and the end effectors  44   a ,  44   b  are similarly axially displaced relative to each other, from the positions shown in FIG. 2 to the positions shown in FIG.  5  and vice versa. When the spool  22  and shaft  20  are in the approximate position shown in FIG. 1, the cylindrical sleeve  40  and the end effectors  44   a ,  44   b  will be in the approximate position shown in FIG. 2; i.e., with the jaws open. Thus, when the spool  22  is moved towards the thumb ring  24 , or vice versa, the cylindrical sleeve  40  and the end effectors  44   a ,  44   b  will be brought into the approximate position shown in FIG. 4; i.e., with the jaws closed. Moreover, it will also be appreciated that it is preferable to move the thumb ring  24  relative to the spool  22 , rather than vice versa since that will move the cylindrical sleeve  40  relative to the end effectors  44   a ,  44   b  rather than vice versa. This is desirable so that the end effectors are not moved away from a tissue sample while the jaws are being closed. 
     Turning now to FIGS. 7 a  through  7   e,  the operation of the multiple sample bioptome of the invention is illustrated schematically in sequence. As seen in FIG. 7 a , a first tissue sample is taken by positioning the jaw cups  46   a ,  46   b  around a tissue  60  to be sampled. The handle  12  of the bioptome  10  is operated as described above so that the cylindrical sleeve  40  is moved distally over the narrow arms  50   a ,  50   b  of the jaw assembly  44  to the position approximately shown in FIG. 7 b.  When the sleeve  40  is moved toward this position, the jaw cups  46   a ,  46   b  are brought close to each other and the sharp rims  48   a ,  48   b  of the jaw cups  46   a ,  46   b  engage the tissue  60  and bite into it. Contemporaneously, and as seen with reference to FIGS. 7 f - 7   h , the knife sharp edge  42  of the sleeve  40  severs any tissue  60  extending from the lateral sides of the jaw cups  46   a ,  46   b . A first sample  60   a  of the tissue  60  is thereby trapped between the jaw cups  46   a ,  46   b  and severed from the tissue  60 . It should be noted that while taking the bite, the coil  16  is not free to stretch, as it is kept longitudinally stiff by the shrink wrap or sheath  15  which preferably extends along the length of the coil  16 . If desired, a wire can be used instead of the shrink wrap or sheath. The wire, which would typically be flat, would be attached to the proximal and distal ends of the coil to keep the coil in tension and prevent it from stretching as the sleeve is moved forward and a bite taken. 
     With the end effectors  44   a ,  44   b  in the position approximately shown in FIG. 7 b , the multiple sample bioptome  10  may be relocated to another tissue area for sampling. The handle  12  of the bioptome  10  is operated as described above so that the cylindrical sleeve  40  is moved proximally over the narrow arms  50   a ,  50   b  of the jaw assembly  44  to the position approximately shown in FIG. 7 c . When the sleeve  40  is moved towards this position, the jaw cups  46   a ,  46   b  are biased apart by the resilience in the gently bent portions  53   a ,  53   b  of their respective arms  50   a ,  50   b . The jaw cups can then be positioned around a second tissue  61  for sampling. The procedure described above with reference to FIGS. 7 a  and  7   b  is repeated. In this instance, however, as the jaw cups  46   a ,  46   b  are brought into position, the tissue  61  pushes the first sample  60   a  proximally away from the jaw cups  46   a ,  46   b  and into the space between the narrow arms  50   a ,  50   b  as seen in FIG. 7 c . Those skilled in the art will appreciate that the tissue sample  60   a  is typically gummy and pliant and will stick to and move along one or both of the narrow arms  50   a ,  50   b  of the end effectors  44   a ,  44   b . The samples will also stick to each other. Upon the taking of a sample  61   a  from the tissue  61 , both samples  60   a  and  61   a  are safely trapped between the narrow arms  50   a ,  50   b  of the end effectors  44   a ,  44   b  as shown in FIG. 7 d . The procedure described above with reference to FIGS. 7 a  through  7   d  is then repeated as suggested in FIG. 7 e  until the space between the arms  50   a ,  50   b  is filled with samples  60   a ,  61   a , etc. According to a presently preferred embodiment of the invention, four to six samples may be captured between the arms of the jaw assembly. The presently preferred dimensions of the end effectors are approximately 0.45 inch in length by approximately 0.095 in height. 
     FIGS. 7 f - 7   h  show a top view of the sequence of operations depicted in side views in FIGS. 7 a  and  7   b . From the top view of FIG. 7 f , it can be seen that the tissue  60  extends beyond the sides of the jaw cups  46   a ,  46   b . The knife-sharp distal edge  42  of the cylinder  40  severs the tissue  60  which extends beyond the jaw cups so that the sample  60   a  can be removed from the tissue  60  as shown in FIGS. 7 g  and  7   h.    
     As mentioned herein above, there are several ways other than welding in which the distal end  18   a  of the control wire  18  may be coupled to the cylindrical sleeve  40 . In particular, FIGS. 8 a  through  9   b  show two other mechanisms for coupling the distal end of the control wire  18  with the sleeve. 
     As shown in FIGS. 8 a  and  8   b , the distal end  18   a  of the control wire  18  is provided with a Z-bend. The side wall of the cylindrical sleeve  40  is punched with two spaced apart semicircular holes  145   a ,  145   b  leaving a bendable narrow strip  145   c  between them. The narrow strip  145   c  is bent radially inward a distance sufficient to accommodate the distal end  18   a  of the control wire  18 . The Z-bend of the distal end  18   a  of the control wire  18  is inserted through the space formed between the narrow strip  145   c  and the semicircular holes  145   a ,  145   b  as shown in FIGS. 8 a  and  8   b.    
     As shown in FIGS. 9 a , and  9   b , the side wall of the cylindrical sleeve  40  is punched with a first hole  245   a  and a second hole  245   c  which is circumscribed by the first hole  245   a . The first hole  245   a  is preferably rectangular, semicircular, or trapezoidal in shape to form a bendable tab  245   b  which is bent radially inward as shown best in FIG. 9 b.  The Z-bend of the distal end  18   a  of the control wire  18  is inserted through the second hole  245   c  in the bendable tab  245   b  as shown in FIGS. 9 a  and  9   b.    
     FIGS. 10 and 10 a  show another embodiment of a multiple sample bioptome  310  of the invention which is particularly suited for cervical biopsy procedures or other laparoscopic biopsy procedures where the biopsy site is approachable in a relatively short and direct path rather than through the long tortuous path of the lumen of an endoscope. In this embodiment, a proximal actuation mechanism  312  is provided with a fixed handle portion  324  and a movable lever portion  322  which is coupled to the fixed handle portion  324  by a pivot pin  323 . A hollow tube  340  is coupled at its proximal end to the movable lever portion  322  of the actuation mechanism  312  by a cross pin  341  or other suitable fastening means. The distal end  340   a  of the tube  340  is provided with a knife sharp edge  342 . A relatively rigid rod  318  extends through the tube  340  and is coupled at its proximal end to the fixed handle portion  324  by means of a cross pin  319  or other suitable fastening means. The distal end  318   a  of the rod  318  is hollow and internally threaded with threads  370  to receive an externally threaded screw  302 . 
     As best shown in FIG. 10 a , the distal end of the rod  318  is coupled to a jaw assembly  344  which includes end effectors  344   a ,  344   b , the screw  302 , and a washer  304  . In particular, the angled proximal ends  352   a ,  352   b  of the narrow arms  350   a ,  350   b  of the end effectors  344   a ,  344   b  are fastened between the washer  304  and the threaded screw  302  which is threaded into the hollow threaded distal end  318   a  of the rigid rod  318 . 
     As shown in FIG. 10, the fixed handle portion  324  is provided with a lower thumb ring  324   a  and the movable lever portion  322  is provided with a lower finger ring  322   a . The upper end  322   b  of the movable lever portion  322  is provided with a slot  322   c  for engaging the cross pin  341  and the rod  318  is provided with a slot  317  through which the cross pin passes. Those skilled in the art will appreciate that the actuation mechanism  312  is manipulated using a conventional scissors-grip. Pivotal movement of the movable lever portion  322  of the actuation mechanism  312  as indicated by the arrows  321  results in linear movement of the tube  340  as indicated by the arrows  339 . It will also be appreciated that the slots  317  and  322   c  may be dimensioned to limit movement of the tube  340 . Because of the geometry of arms  350   a ,  350   b  of the end effectors  344   a ,  344   b , movement of the tube  340  relative to the rod  318  results in a riding of the tube  340  over the arms  350   a ,  350   b , and an opening and closing of the jaws as described above. It should be appreciated that, if desired, the actuation mechanism  312  may be used with the flexible coil and pull wire described with reference to FIGS. 1 and 2. Conversely, the actuation mechanism  12  described with reference to FIG. 1 may be used with the tube and rod arrangement of FIG.  10 . It will also be appreciated that instead of making the push rod  318  fixed in the non-moving handle  324 , and the tube  340  movable with the lever  322 , the push rod  318  could move, and the tube  340  could be fixed. With such an arrangement, movement of the lever relative to the handle would cause the end effectors  344   a ,  344   b  to be drawn into the tube  340 , with the jaws closing, and with the jaws and the sharp end  342  of the tube  340  severing the tissue. 
     It will be appreciated that all of the embodiments of the multiple sample bioptome shown in FIGS. 1-10 a  can be provided with a cautery capability. For example, as seen in FIG. 10, a cautery contact  398  is provided which contacts the rigid rod  318  and extends out of the fixed portion  324  of the handle  312 . In addition, the tube  340  is preferably provided with shrink wrap or other insulation  399 . With this arrangement, when a cautery current is applied to the cautery contact  398 , the jaw assembly  344  is electrified via its connection to the rod  318 . Typically, cauterization would be carried out after a sample is obtained and severed from the surgical site with the jaws still located at the surgical site. Because the body of the patient acts as the second electrode (ground), current flows from the jaws into the patient at the surgical site, thereby effecting a cauterization of the surgical site rather than cauterizing the sample in the jaws. 
     Turning now to FIGS. 11,  11   a , and  11   b , another embodiment of a jaw assembly  444  includes a pair of end effectors  444   a ,  444   b  and a mounting screw  402  for coupling the jaws to the distal end  16   a  of a flexible coil  16 . Each end effector  444   a ,  444   b  includes a jaw cup  446   a ,  446   b  preferably having an array of radially arranged cutting teeth  448   a ,  448   b  and a resilient, preferably narrow, arm  450   a ,  450   b  which extends proximally from the jaw cup  446   a ,  446   b . The exterior surface of the jaw cup  446   a ,  446   b  is preferably provided with a closing cam  447   a ,  447   b  as described in co-pending co-owned application Ser. No. 08/412,058 , filed Mar. 28, 1995, which is hereby incorporated by reference herein. The narrow arm  450   a ,  450   b  is provided with a mounting hole  452   a ,  452   b  at its proximal end  451   a ,  451   b  and a gently angled portion  453   a ,  453   b . At least the gently angled portion  453   a ,  453   b  of the arms  450   a ,  450   b , and preferably the entire arms  450   a ,  450   b  are formed from super-elastic metal such as Nitinol, and are biased apart from each other (due to angled portions  453   a ,  453   b  of the arms  450   a ,  450   b ), thereby urging the jaw cups  446   a ,  446   b  apart (as seen in FIG. 11 b ). In addition, as the arms  450   a ,  450   b  and the jaws  446   a ,  446   b  are preferably integral with each other, the jaws are preferably formed from a super-elastic metal. 
     According to the embodiment shown in FIGS. 11,  11   a , and  11   b , the proximal end  451   a ,  451   b  of each arm  450   a ,  450   b  is coupled to the distal end  16   a  of the coil  16  by crimping/locking with the hollow threaded screw  402  as best illustrated in FIGS. 11 a  and  11   b . The threaded screw  402  is substantially cylindrical, and generally includes a head portion  406 , a threaded portion  408 , and a cylindrical throughbore  410  along its central axis. The throughbore  410  is dimensioned to receive and allow lateral movement of the control wire  18  as described above with reference to FIGS. 5-7. The head portion  406  has a diameter substantially equal to that of the outer diameter of the coil  16 , and is provided with two opposed grooves  414   a ,  414   b  on the outer perimeter of the head portion  406 . The grooves  414   a ,  414   b  are provided with side peaks  415   a ,  415   b  and a raised pin  417   a ,  417   b , and are dimensioned to receive the proximal ends  451   a ,  451   b  of each of the narrow arms  450   a ,  450   b . The proximal ends  451   a ,  451   b  of the arms  450   a ,  450   b  are placed in the respective grooves  414   a ,  414   b  so that the pins  417   a ,  417   b  engage respective mounting holes  452   a ,  452   b . The pins  417   a ,  417   b  are flattened like rivets and the peaks  415   a ,  415   b  of the grooves are folded over the arms as shown best in FIGS. 11 a  and  11   b.  The threaded portion  408  of the hollow screw  402  has a diameter substantially equal to the inner diameter of the coil  16  and threadably engages the interior of the distal end  16   a  of the coil  16  as shown in FIG. 11 b.    
     FIGS. 12 and 12 a - 12   c , show yet another embodiment of mounting jaws at the distal end of a flexible coil. A jaw assembly  544  includes a pair of end effectors  544   a ,  544   b  and a mounting screw  502  for coupling the jaws to the distal end  16   a  of a flexible coil  16 . Each end effector  544   a ,  544   b  includes a jaw cup (not shown) which is substantially the same as any of the previously described embodiments, and a resilient, preferably narrow, arm  550   a ,  550   b  which extends proximally from the jaw cup. The narrow arm  550   a ,  550   b  is provided with semi-cylindrical portion  552   a ,  552   b  at its proximal end  551   a ,  551   b  which terminates with a pair of proximally extending tabs  553   a ,  553   b ,  555   a ,  555   b.    
     According to the embodiment shown in FIGS. 12 and 12 a - 12   c , the proximal end  551   a ,  551   b  of each arm  550   a ,  550   b  is coupled to the distal end  16   a  of the coil  16  with the hollow threaded screw  502  as best illustrated in FIGS. 12 b  and  12   c . The threaded screw  502  is substantially cylindrical, and generally includes a head portion  506 , a threaded portion  508 , and a cylindrical throughbore  510  along its central axis. The throughbore  510  is dimensioned to receive and allow lateral movement of the control wire  18  as described above with reference to FIGS. 5-7. The distal end of the head portion  506  has a diameter substantially equal to that of the outer diameter of the coil  16 , and is provided with two pair of opposed grooves  514   a ,  514   b ,  516   a ,  516   b  on the outer perimeter of the head portion  506 . The grooves are dimensioned to receive the proximal ends  551   a ,  551   b  of each of the narrow arms  550   a ,  550   b , as shown best in FIGS. 12 b  and  12   c , with the semi-cylindrical portions  552   a ,  552   b  lying on the reduced diameter proximal portion of the head  506 , the tabs  553   a ,  553   b  residing in the groove  516   a , and the tabs  555   a ,  555   b  residing in the groove  516   b . The threaded portion  508  of the hollow screw  502  has a diameter substantially equal to the inner diameter of the coil  16  and threadably engages the interior of the distal end  16   a  of the coil  16  as described above. 
     FIGS. 13,  13   a , and  13   b  show a presently preferred embodiment of coupling a jaw assembly to the distal end of a coil. According to this embodiment, the jaw assembly  560  includes a pair of end effectors  562   a ,  562   b , a mounting screw  564 , and a retaining sleeve or washer  566 . Each end effector  562   a ,  562   b  includes a jaw cup  568   a ,  568   b  and a resilient, preferably narrow, arm  570   a ,  570   b  which extends proximally from the cup. The proximal end of each arm  570   a ,  570   b  is provided with a mounting hole  572   a ,  572   b . In all other respects, the end effectors may incorporate various features of the end effectors described above. The mounting screw  564  is similar to the mounting screw  402  described above. It is substantially cylindrical, having a head portion  564   a , a threaded portion  564   b , a through bore  564   c , and a pair of diametrically opposed arm receiving grooves  564   d ,  564   e , each of which is provided with an upstanding pin  564   f ,  564   g . In this embodiment, a proximal portion  564   h  of the screw head  564   a  has a reduced diameter which is substantially equal to the inner diameter of the retaining sleeve or washer  566 . The upstanding pins  564   f ,  564   g  are located on this proximal portion  564   h  of the screw head  564   a . From the foregoing, those skilled in the art will appreciate that the end effectors  562   a ,  562   b  are coupled to the screw  564  by placing respective arms  570   a ,  570   b  in the grooves  546   d ,  564   e  so that the respective mounting holes  572   a ,  572   b  are engaged by the respective pins  564   f ,  564   g . After the arms are so arranged relative to the screw, the sleeve or washer  566  is placed over the proximal portion  564   h  of the screw head  564   a  and the proximal ends of the arms are captured between the sleeve and the screw head. The threaded portion  564   b  of the screw is then coupled to the distal end of a coil (not shown) as described above and the sleeve or washer  566  is captured between the coil and the screw head as described above. 
     As mentioned above, the jaw cups are opened and closed by movement of a cylindrical sleeve which is coupled to a control wire. FIGS. 14,  14   a , and  14   b  show another embodiment of a cylindrical sleeve  640  coupled to the distal end  618   a  of a control wire  618  for opening and closing a jaw assembly  644  which is coupled to the distal end  16   a  of a flexible coil  16 . The jaw assembly  644  is substantially the same as any of the various jaw assemblies described above. Notably, the jaw assembly has two relatively narrow spaced apart arms  650   a ,  650   b  According to the embodiment of FIGS. 14,  14   a , and  14   b , a cross member  628  is coupled to the distal end  618   a  of the control wire  618 . The cross member  628  is a disk segment having two opposite substantially parallel sides  628   a ,  628   b , two curved sides  628   c ,  628   d  having radii of curvature which correspond to the inner radius of the cylindrical sleeve  640 , and a central bore  628   e . The distance between the parallel sides  628   a  and  628   b  is less than the distance between the interior surfaces of the arms  650   a ,  650   b  of the jaw assembly; and the distance between the curved sides  628   c  and  628   d  is substantially equal to the interior diameter of the cylindrical sleeve  640 . The diameter of the bore  628   e  is substantially equal to the diameter of the control wire  618 . The control wire  618  is coupled to the cross member  628  by inserting the distal end  618   a  of the control wire through the bore  628   e  and crimping the control wire on either side of the cross member as shown best in FIGS. 14 and 14 a.  The cross member  628  is aligned relative to the jaw assembly  644  so that it extends freely between the arms  650   a  and  650   b  as seen best in FIGS. 14 a  and  14   b . The cylindrical sleeve  640  is coupled to the cross member  628  by crimping the sleeve on either side of the cross member  628  at  699  as seen best in FIG. 14 a.    
     There have been described and illustrated herein several embodiments of an endoscopic multiple sample bioptome. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. Thus, while the jaw assembly has been disclosed as being formed from a particular super-elastic metal, it will be understood that other super-elastic alloys can be used to achieve the same or similar function as disclosed herein. For example while the jaws have been disclosed as made out of a nickel-titanium alloy, they may also be made out of, e.g., iron-platinum, silver-cadmium, nickel-aluminum, manganese-copper, copper-zinc, nickel-thallium, or any other super-elastic alloy. It will furthermore be appreciated that while the apparatus of the invention was described as advantageously permitting the obtaining of multiple biopsies without removal from the surgical site, the apparatus of the invention, if desired, could still be used for obtaining single biopsies at a time. In fact, the endoscopic instrument need not be used for taking biopsies at all, but could be used as a dissector. In a dissector embodiment, the tube which causes the arms to close would not have a sharp end, and the end effectors could be paddle or otherwise shaped rather than having jaw cups. Moreover, while particular configurations of the actuation mechanism of the invention have been disclosed, it will be appreciated that other types of actuation mechanisms could be utilized. Also, while specific couplings of the ends of the coil and control wire have been shown, it will be recognized that other types of couplings could be used with similar results obtained. Similarly, while specific couplings of the ends of the rigid tube and rod have been shown, it will be understood that other types of couplings could be used. Moreover, while particular configurations have been disclosed in reference to the jaw assembly, it will be appreciated that other configurations could be used as well. For example, while it is preferred to provide jaws with sharp edges, it will be appreciated that in lieu of edges, the jaws can be provided with sharp teeth which, in conjunction with the sharp cylinder, will provide a cutting ability. Furthermore, while in the second embodiment the inner rod is shown to be stationary and the outer tube is shown to be adjustable, the outer tube may be made stationary and the rod adjustable. It will therefore be appreciated by those skilled in the art that yet other modifications could be made to the provided invention without deviating from its spirit and scope as so claimed.