Abstract:
A method and device for incising tissue within the gastrointestinal tract is described. The device is an electrosurgical sphincterotome cutting device. The sphinctertome includes a pre-curved, heat set FEP distal tip. An electrically conductive cutting wire is positioned along the pre-curved distal tip. Manipulating a control handle tightens the cutting wire and incises and cauterizes target tissue. The curvature of the distal tip allows the sphincterotome to orient and steer itself towards a patient&#39;s sphincter as it emerges from an accessory channel of an endoscope.

Description:
TECHNICAL FIELD 
       [0001]    The invention generally relates to a sphincterotome having a pre-curved distal tip that provides controlled cutting and orientation during, for example, the cutting of a patient&#39;s sphincter. 
       BACKGROUND 
       [0002]    Gastrointestinal endoscopy is commonly used to gain access to the digestive tract for the purpose of incising and cauterizing tissue. Many common endoscopy procedures exist for achieving this purpose. 
         [0003]    Endoscopic sphincterotomy is a specific procedure in which a sphincterotome is used in combination with an endoscope to surgically cut a patient&#39;s sphincter. As one example, the sphincterotome may be used to partially cut open the duodenum at the Papilla of Vater to access the common bile duct and remove bile duct stones which form an obstruction therewithin. Conventional sphincterotomes utilized in this technique can create major complications, including bleeding, pancreatitis, perforation, and cholangitis. Bleeding is a common complication which arises when the retroduodenal artery is inadvertently cut. This inadvertent cut of the artery may often be caused by a lack of cutting control of the sphincterotome. As a result, practitioners must be able to properly orient the cutting wire of the sphincterotome at the optimal location for accessing the sphincter or papilla of a patient. 
         [0004]    Inducing a curve or bend in the distal end of the sphincterotome may facilitate the proper orientation of the device. This is typically accomplished by placing a shaping wire in the wire guide lumen at the distal end of the sphincterotome. The shaping wire tends to curve, at least temporarily, the distal end of the device. However, because of the materials typically used to form the shaft of the distal end of the sphincterotome, the distal end of the device may begin to straighten as soon as the shaping wire is removed. Thus, it is often necessary to re-insert the shaping wire to re-curve the distal end of the device, thereby increasing the duration of the procedure. In addition, the distal end of the sphincterotome tends to straighten as the device is advanced through the endoscope towards the patient&#39;s papilla. As a result, it may be difficult to cannulate the biliary or pancreatic ducts and achieve the desired cutting orientation. This can also increase procedure time and may result in the improper cutting of the papilla. As a result, conventional sphincterotomes are prone to the problem of achieving adequate orientation. The inability to achieve adequate orientation may lead to uncontrolled cutting and cauterization. The use of a shaping wire may also interfere with the ability to pre-load a wire guide or other elongate device into the sphincterotome, thereby further increasing the complexity and duration of the procedure. 
         [0005]    In view of these drawbacks of current technology, there is an unmet need for incision devices that can controllably access, cut and cauterize tissue without inducing significant patient trauma. 
       SUMMARY 
       [0006]    Accordingly, an electrosurgical cutting device is provided that resolves or improves upon one or more of the above-described drawbacks. 
         [0007]    In a first aspect, an electrosurgical cutting device is provided. The device comprises a tubular member comprising a proximal end and a distal end. The distal end comprises a heat-set, pre-curved distal tip formed from fluorinated ethylene propylene (FEP). An electrically conductive cutting element is located along the distal end of the tubular member. The cutting element is connected to an electrical conductor extending within a lumen. The cutting element extends exteriorly of the tubular member along an inner radius of curvature of the distal tip. The cutting element is moveable within a cutting plane. The arrangement insures that the distal tip of the tubular member will maintain the desired cutting orientation as it emerges from a distal end of a working channel of an endoscope so as to position the cutting element within the desired cutting plane. A wire guide may be pre-loaded through a wire guide lumen of the electrosurgical cutting device with a distal end of the wire guide extending beyond the distal end of the tubular member. 
         [0008]    In a second aspect, a method of fabricating an electrosurgical cutting device is provided. A proximal end of an electrical conductor is attached to an electrical connector of a handle. The handle is affixed to a substantially linear tubular member formed from fluorinated ethylene propylene (FEP). An electrical conductor is threaded through a lumen. A distal free end of the electrical conductor is passed through a proximal luminal opening of the tubular member along the distal tip and outward of the lumen to form a cutting element. A distal free end of the cutting element is reinserted through a distal luminal opening of the tubular member into the lumen to secure the distal end within the lumen. A distal end of the straight tubular member is heat set into a curved distal tip that conforms to a shape of a scaffolding structure having a corresponding curved distal end. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Embodiments will now be described by way of example with reference to the accompanying drawings, in which: 
           [0010]      FIG. 1  is a perspective view of a sphincterotome and loop tip wire guide according to an embodiment; 
           [0011]      FIG. 2  is a cross sectional view of  FIG. 1  taken along cutting line III-III showing a wire guide extending through one of the lumens of the sphincterotome and an electrical conductor extending through the other lumen; 
           [0012]      FIG. 3  is a side view of the distal tip of the sphincterotome with cutting wire in the 12 o&#39;clock orientation relative to the papilla as the sphincterotome emerges from a distal end of an accessory channel of an endoscope, the distal tip being navigated over the loop tip wire guide; 
           [0013]      FIG. 4  is a perspective view of the distal tip of the sphincterotome in a desired cutting plane configuration; 
           [0014]      FIG. 5  is a view of the papilla with the cutter oriented in the 12 o&#39;clock position relative to the papilla; 
           [0015]      FIG. 6  is a partial view of the pre-curved sphincterotome being used to perform an endoscopic sphincterotomy procedure; 
           [0016]      FIG. 7  is a plan view of a packaging tray used for shipping, handling, and storing the pre-curved sphincterotome with pre-loaded wire guide therein; and 
           [0017]      FIGS. 8-10  are side views of the cutting wire of the sphincterotome at various locations along the pre-curved distal tip. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    The embodiments are described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of the embodiments are better understood by the following detailed description. However, the embodiments as described below are by way of example only, and the invention is not limited to the embodiments illustrated in the drawings. It should also be understood that the drawings are not to scale and in certain instances details have been omitted, which are not necessary for an understanding of the embodiments, such as conventional details of fabrication and assembly. 
         [0019]    An exemplary sphincterotome is shown in  FIG. 1 .  FIG. 1  is a perspective view of a sphincterotome  100  and a separate loop tip wire guide  190  (which has been enlarged for clarity). The sphincterotome  100  includes a tubular member  130  having a proximal region  150  and a distal region  140 . The proximal region  140  includes a control handle  120 . The control handle  120  comprises a movable hand portion  180  which may be drawn proximally to draw tension on a conductor wire  200  ( FIG. 2 ) during an endoscopic sphincterotomy procedure. The distal region  140  includes a pre-curved distal tip  110 . The term “pre-curved” as used herein refers to a distal tip of a fluorinated ethylene propylene (FEP) tubular member  130  that is heat set into a permanently curved configuration during fabrication.  FIG. 1  shows the pre-curved distal tip  110  in its normal, relaxed state. At least the pre-curved distal tip  110  is formed from FEP. FEP is a thermoplastic which can be melt processed and shaped by application of pressure and heat. The polymeric chemical structure of FEP enables it to be readily shaped using conventional thermoplastic processing techniques, including injection, transfer, blow, and compression molding as well as screw extrusion. Thermoset materials, on the contrary, cannot be melt processed. PTFE is one of the most common thermoset materials used in medical devices because of its excellent chemical resistance. As a result, PTFE is typically used to manufacture the tubular shaft portion of conventional sphincterotomes. However, PTFE does not have a chemical structure that is amenable to melt processing because the chemical structure of PTFE includes strong C—F bonds in which the fluorine atoms are packed tightly in a spiral manner about the carbon backbone, which is what makes PTFE one of the most chemically resistant synthetic polymeric materials. 
         [0020]    The FEP tubular member  130  may be extruded and thereafter a portion of the distal region  140  may be heat set into the pre-curved distal tip  110  having the desired cutting orientation as shown in  FIG. 1 . Generally speaking, during an endoscopic sphincterotomy procedure, as the pre-curved distal tip  110  emerges from the working channel  380  of an endoscope  370 , it orients into the optimal 12 o&#39;clock position ( FIGS. 3 ,  5 , and  6 ) thereby enhancing the ease of cannulation. The pre-curved distal tip  110  maintains its orientation with the cutting plane P ( FIG. 4 ) which enables the cutting wire  160  to approach a patient&#39;s papilla  510  at the desired 12 o&#39;clock orientation relative to the papilla  510 . 
         [0021]    Because the FEP pre-curved distal tip  110  is at the time of fabrication oriented into the desired curved orientation, shaped forming wires or other reinforcing means are not needed to form and maintain the distal tip  110  in the curved shape during shipping and storage prior to use. Accordingly, the absence of a need for a forming wire within the wire guide lumen  210  ( FIG. 2 ) allows a loop tip wire guide  190  ( FIG. 1 ) or other elongate medical device to be pre-loaded therethrough.  FIG. 1  shows an exemplary loop tip wire guide  190  (not drawn to scale) that may be pre-loaded within the wire guide lumen  210  ( FIG. 2 ) and positioned so as to extend the distal loop tip  191  beyond the distal edge  161  of pre-curved distal tip  110  of tubular member  130 . This is in contrast to conventional sphincterotomes which cannot be pre-loaded with a loop tip wire guide. Therefore, the absence of the need for the forming wire in the sphincterotome  100  of the present invention allows a loop tip wire guide  190  to be pre-loaded within the sphincterotome  100 . Other devices may also be pre-loaded within the lumen  210 . As will be later described, the pre-loaded sphincterotome  100  may be packaged as shown in  FIG. 7 . The loop tip wire guide  190  unlike other elongate devices, such as a non-loop tip wire guide, presents the additional problem of being pre-loaded into sphincterotome  100  by advancing it at the proximal end of the sphincterotome  100  rather than through the distal end of the sphincterotome  100 . Although it is possible to pre-load other medical devices by partially advancing them through the proximal end of the sphincterotome  100 , the loop tip wire guide  190  cannot be advanced into the sphincterotome  100  due to the presence of a forming wire blocking the lumen  210 . 
         [0022]    Although  FIG. 2  shows two lumens extending through tubular member  130 , more than two lumens are also contemplated. For example, a third lumen may be dedicated for the passage of fluids or contrast fluid therethrough. 
         [0023]    Preferably,  FIG. 2  shows that the sphincterotome  100  comprises two lumens. Lumen  210  is adapted to receive a wire guide, including the loop tip wire guide  190  of  FIG. 1 . This lumen  210  may also be configured for the passage of fluids or contrast therethrough. Lumen  170  is adapted to receive an electrical conductor wire  200 . Although the lumens  170  and  210  are shown with circular cross-sectional shapes, other lumen shapes are possible. 
         [0024]    The electrical conductor wire  200  transmits current to the cutting wire  160 . The conductor wire  200  is a wire extending through lumen  170  ( FIG. 2 ) and is connected at its proximal end to electrical connector  181  ( FIG. 1 ) to provide a high frequency electrical current to conductor  200  and cutting wire  160  as is well known to one of ordinary skill in the art. Conductor  200  protrudes outward of the wall of tubular member  130  at the distal tip  110  through first opening  111  to become cutting wire  160 . The cutting wire  160  is bowed between the first opening  111  and the second opening  112  and is disposed outside of the wall of tubular member  130 . The cutting wire  110  re-enters the wall of the tubular member  130  through second opening  112  and extends proximally through the lumen  170 . Preferably, the conductor  200  and cutting wire  110  may be formed from a single wire. Alternatively, the cutting wire  110  and conductor  200  may be distinct components that may be connected to each other by soldering or other conventional means known in the art. 
         [0025]    Although  FIG. 1  shows the cutting wire  160  positioned near the distal end  161  of the distal tip  110 , the cutting wire  160  may be positioned at different locations along the pre-curved distal tip  110 . Additionally, the cutting wire  160  may be of various lengths by changing the proximal and distal openings  111  and  112 .  FIG. 8  is an enlarged view of  FIG. 1 , showing the cutting wire  160  positioned at the distal edge  161  of distal tip  110  along the inner radius of the pre-curved distal tip  110 .  FIGS. 9 and 10  show the cutting wire  160  positioned substantially along the center of the pre-curved distal tip  110 . The primary difference between  FIG. 9 and 10  is that the cutting wire  160  of  FIG. 10  is longer than the cutting wire  160  of  FIG. 9 . As a result, the cutting wire  160  of  FIG. 10  may be able to remove a larger amount of tissue or cut to a greater depth. The specific location of the cutting wire  160  along the distal tip  110  is dependent upon many factors, including the amount of tissue being cut and cauterized. 
         [0026]    The proximal end of the conductor wire  200  is connected to the control handle  120  such that actuation of the handle assembly  120  partially retracts (i.e., pulls in a proximal direction) the conductor wire  200  and cutting wire  160  to exert a tension therealong. This causes the distal end of the cutting wire  160  to pull against the already pre-curved distal tip  110 , thereby causing the distal tip  110  to bow inwards even more to further reduce the inner radius of the pre-curved distal tip  110 . Electric current that passes through the conductor wire  200  from electrical connector  181  in the control handle  120  enables the cutting wire  160  to act as an electrosurgical cutting element that may be used to cut and cauterize tissue, such as the sphincter of Oddi. 
         [0027]    The distal edge  161  of tubular member  130  may comprise a tapered shaped end. The tapered distal edge  161  may comprise a reduction in wall thickness of tubular member  130  and a reduction in outer diameter. Because the tapered distal edge  161  comprises rounded edges, it may mitigate trauma to a patient as the distal edge  161  is being navigated within a body lumen. The FEP distal edge  161  may be tapered under suitable heat and pressure and is relatively easier to shape compared to tips not formed from thermoplastics. For example, because tips made from PTFE are not readily melt processable, relatively higher pressures and temperatures are required to form a tapered tip. Such higher pressures and temperatures may likely translate into relatively more energy intensive and expensive process compared to distal tips formed from FEP. 
         [0028]    A radiopaque marker band  165  ( FIG. 1  and  FIG. 6 ) may be thermally bonded along the distal tip  110  to enable fluoroscopic visualization of the distal tip  110  as it is being maneuvered. The radiopacity of the distal tip  110  provides information to a physician regarding the location and orientation of the distal portion  110  in various body lumens that the sphincterotome  100  is being guided through. Conventional sphincterotomes formed from thermoset materials such as PTFE cannot be reheated so as to form a thermal bond with the radiopaque marker band  165  because PTFE is not a melt processable material. Reheating of PTFE results in reaching PTFE&#39;s thermal decomposition temperature before its melting point is obtained. As a result, PTFE cannot be melted and re-shaped after it is cured. PTFE sphincterotomes generally utilize a metallic band mechanically secured by, for example, crimping about the catheter shaft, in which no thermal bonding occurs. There may be a risk that the crimped metallic band is not effectively secured to the shaft and could detach from the tubular member. Accordingly, the ability for a FEP tubular member  130  to be thermally bonded with a radiopaque marker band  165  is advantageous. 
         [0029]    Various techniques may be utilized to form the pre-curved distal tip  110 . In one example, an internal curved mandrel may be utilized in which the mandrel is inserted into one of the lumens of the tubular member  130 . Because FEP is soft at room temperature, the FEP tubular member  130 , which is substantially a straight extruded tubing when initially formed, is flexible enough to accommodate the curved shape mandrel. The mandrel may be back loaded into wire guide lumen  210  from the distal edge  161  of tubular member  130 . The length of mandrel may be the length of the resultant distal tip  110  ( FIG. 1 ). Alternatively, the mandrel may be longer, having a straightened proximal portion. Having loaded the curved mandrel within one of the lumens of the FEP tubular member  130 , the heat setting process may begin. The process variables for heat setting are generally temperature, time and pressure and may be adjusted as needed to create the necessary curved distal tip  110 . Specifically the heat-setting temperature is sufficient for the FEP thermoplastic material to lose its crystallinity and become amorphous in structure such that that the FEP material becomes flowable, thereby conforming to the curved shape of the internal mandrel. In one embodiment, the heat setting procedure involves heating the FEP material to about (300-600)° F. for Up to about 15 minutes. Suitable ranges of temperatures, time and pressures appropriate for the heat-setting process may be readily determined by those skilled in the art. Having shaped at least a portion of the distal region  140  of the tubular member  130  into a curved distal tip  110 , the resultant curved shape is quenched in a cool down cycle at a predetermined cooling rate. The precise cooling rate varies depending on numerous factors, including the desired crystallinity and amorphousness of the resultant FEP pre-curved distal tip  110 . In one embodiment, the cool down cycle involves cooling the FEP material to about ambient temperature for about 5 minutes. 
         [0030]    Alternatively, an external mandrel may be utilized in which the tubular member  130  is inserted into a passageway of the mandrel. Upon suitable heat and pressure for a given duration of time, a portion of the distal region  140  becomes heat set into a curved distal tip  110 . In one embodiment, the heat setting procedure involves heating the FEP material to about (300-600)° F. for up to about 15 minutes. 
         [0031]    In another example, a standard aluminum forming plate (not shown) having a channel taking the shape of the desired curvature is utilized. Because FEP is soft at room temperature, the FEP linear tube  130  renders the tube  130  flexible enough to be forced within the channel of the aluminum forming plate. Conductive heating elements raise the surface temperature of the channel, thereby heating the FEP linear tube  130  at a predetermined heating rate readily known to those of ordinary skill in the art. The linear tube  130  is heated until it becomes malleable and attains the shape of the curved channel. The residual stresses imparted to the linear FEP tube  130  when fitting the tube  130  into the curved channel at room temperature disappears upon the heat treatment. The permanently curved tube  130  is now quenched to room temperature by placing the aluminum forming plate on a cooling plate having chilled water running through tubes contained within the cooling plate. In one embodiment, the cool down cycle involves cooling the FEP material to about ambient temperature for about 5 minutes. 
         [0032]    Once the linear FEP tube  110  has been transformed into a pre-curved distal tip  110 , the curved tubular FEP member  150  may now be affixed to a non FEP proximal portion (e.g., PTFE) by a standard heat bond. No adhesive is required. Other methods for bonding and/or affixing the curved tubular FEP member  130  to a non FEP proximal portion will be apparent to those of ordinary skill in the art. Alternatively, the entire tubular shaft  130  may be formed from FEP. Although the heat setting techniques for imparting a curved orientation have been described in conjunction with mandrels and forming plates, other types of scaffolding structure may be used as known in the art. For example, heat setting with the use of a forming wire may be used to create the pre-curved distal tip  110 . 
         [0033]    The degree of curvature of the distal tip  110  can be characterized by an “angle of curvature”, which refers to the angle of the curved portion of the tubular member  130 , in its relaxed state, as measured from a plane perpendicular to the longitudinal shaft of the tubular member  130  to the distal-most edge  161  of the tubular member  130 .  FIG. 1  shows that the angle of curvature is about 180 degrees. Other angles of curvature are contemplated, partially dependent upon the specific application. Additionally, the distal tip  110  may be characterized by a centerline diameter. The centerline diameter is defined as the diameter that the curved portion of the catheter, in its relaxed state, would create were it a full circle. It may span a range of several millimeters. Accordingly, the tightness of the curved configuration of the distal tip  110  is attributed to the angle of curvature and the centerline diameter. 
         [0034]    Assembly of the sphincterotome  100  is as follows. As already mentioned, the FEP tubular member  130  is extruded by conventional extruding techniques and thereafter curvature is imparted to the extruded FEP member  130  as described above. The tubular member  130  is preferably formed with two lumens  170  and  210 , a cutting wire lumen  170  and a wire guide lumen  210 . More lumens may be utilized. Electrical conductor wire  200  is threaded through lumen  170 . The cutting wire  160  may be formed by passing one free end of the electrical conductor wire  200  through opening  111  ( FIG. 1 ) located in the wall of the distal region  140  of tubular member  130  and radially outward of the lumen  170 . A radially bowed shape cutting wire  160  is formed when the distal end of the cutting wire  160  is reinserted into opening  112  of the wall of tubular member  130  and into lumen  170  where it is threaded proximally back therethrough and then secured by any means as known in the art within the lumen  170 . The proximal end of conductor wire  200  is attached to electrical connector  180  and control handle  120 . 
         [0035]      FIG. 7  shows that packaging tray  710  may be utilized during the shipping and handling of the sphincterotome  100 . A wire guide, such as loop tip wire guide  190  may be preloaded into wire guide lumen  210  ( FIG. 2 ). The packaging tray  710  has a channel  760  that conforms to the natural curvature of pre-curved distal tip  110 . In particular, channel  760  is designed to conform to pre-curved distal tip  110  and is configured with the same angle of curvature and centerline diameter created during imparting curvature to the initially straight extruded FEP tubular member  130 , as explained above. The loop tip  191  of wire guide  190  preferably extends past the distal edge  161  ( FIG. 1 ) of pre-curved distal tip  110  and is packaged within channel  761 . Channel  761  is designed to conform to the loop shape of loop tip  191 . Packaging tray  710  further includes handle opening  734  ( FIG. 7 ) for housing control handle  120  ( FIG. 1 ). FEP tubular member  130  is housed within channel  735 . Another tray (not shown) compliments and mates with packaging tray  710  to enclose the sphincterotome  100 . Accordingly, the packaging tray  710  provides an efficient way for accommodating the sphincterotome  100  with preloaded loop tip wire guide  190  or other device inserted therein during shipping, handling, and storage. 
         [0036]      FIGS. 3 ,  5 , and  6  illustrate how the sphincterotome  100  is used. The distal region  140  of tubular member  130  of sphincterotome  100  is preferably advanced within an accessory channel  380  of an endoscope  370  ( FIG. 3 ). During advancement within the accessory channel  380 , the pre-curved distal tip  110  flexes into a semi-straightened shape. If the loop tip wire guide  190  has been pre-loaded into the sphincterotome  100 , then the tubular member  130  and the loop tip wire guide  190  are advanced simultaneously through the endoscope  370  until the distal tip  110  emerges from the distal opening of the accessory channel  380 . As the distal tip  110  emerges from the distal end of the accessory channel  380 , it relaxes back to its pre-curved shape. During an endoscopic sphinctertomy, the pre-curved distal tip  110  is bent at about 90 degrees or more as it emerges from the distal end of the accessory channel  380 . The progression of the pre-curved distal tip  110  through the distal opening of the accessory channel  380  causes the tip  110  to orient automatically into the 12 o&#39;clock position relative to the papilla  510  as shown in  FIGS. 5 and 6 . Radiopaque marker bands  165  ( FIG. 6 ) along pre-curved distal tip  110  help the practitioner visualize the orientation and location of the pre-curved distal tip  110  relative to the papillary orifice  510 . The 12 o&#39;clock position is shown as a clock face about the papilla  510  and is illustrated in  FIG. 5 . The 12 o&#39;clock position is preferable because it is most visible through the endoscope and it avoids injury to the duodenal wall.  FIG. 5  shows the distal-most portion of distal tip  110  being advanced through the papilla  510  during cannulation of the biliary tree in the 12 o&#39;clock position relative to the papillary orifice  510 . The distal tip  110  is typically advanced along the loop tip wire guide  190 , which is first advanced through the papilla  510  and is subsequently used for guiding the advancement of the sphincterotome  100 . 
         [0037]    Control handle  120  ( FIG. 1 ) is proximally retracted to tighten cutting wire  160  to a flexed orientation as shown in  FIG. 6 . Cutting wire  160  is electrically energized via electrical conductor wire  200  to cut the center of the papilla  510 . Manipulation of control handle  120  causes the cutting wire  160  to move into cutting plane P ( FIG. 4 ) to cut papilla  510 . The pre-curved distal tip  110  enables the cutting wire  160  to maintain orientation within cutting plane P as shown in  FIG. 4 .  FIG. 4  shows that distal region  140  of tubular member  130  and cutting wire  160  is symmetrically disposed about the cutting plane P. 
         [0038]    Performing the above described procedure with sphincterotome  100  is advantageous compared to using a normal sphincterotome for several reasons. Cannulating the biliary duct may become easier because the sphincterotome  100  has the capability to automatically steer and orient itself into the proper configuration during the sphincterotomy procedure. On the contrary, conventional sphincterotomes may sometimes require that a practitioner bend the distal end of the sphincterotome into the optimal orientation, which may require several iterations and often fails to retain its desired shape. The ability to more easily cannulate the duct with a FEP-formed sphincterotome  100  may also translate into reduced patient trauma because the cannulation may likely be achieved more quickly and/or accurately. Additionally, the elimination of a forming wire to maintain an unnatural curvature of conventional sphincterotomes formed from PTFE materials represents a cost reduction. The elimination of the forming wire also provides the opportunity to preload the lumen of the sphincterotome  100  with medical devices, such as loop tip wire guides  190 . Additionally, because the forming wire merely maintains PTFE and other non-thermoplastic sphincterotomes in an unnatural curved position during shipping and handling, the sphincterotome upon use may revert back, to a certain degree, to its straightened configuration, thereby making endoscopic sphincterotomy difficult. The likelihood of reverting back to a straightened configuration may increase if the sphincterotome is not used for a prolonged period of time after shipment. 
         [0039]    The above figures and disclosure are intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in the art. All such variations and alternatives are intended to be encompassed within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the attached claims.