Abstract:
A medical device is provided with a probe including an elongated shaft having a distal end, a proximal end, and an external wall. The probe also includes at least two conductors extending substantially along a longitudinal length of the probe. The probe also includes a strengthening element attached to an outer surface of the external wall of the elongated shaft. The probe is configured to slidably move within a working channel of a delivery device and the strengthening element is configured to limit buckling of the probe as a distal portion of the probe is advanced past a deflection point of the delivery device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent document claims the benefit of the filing date under 35 U.S.C. §119(e) of Provisional U.S. Patent Application Ser. No. 62/218,788 filed Sep. 15, 2015, which is hereby incorporated by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to medical devices and more specifically to electrohydraulic lithotripsy probes. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    Electrohydraulic lithotripsy is a procedure used as a means to break up stones within the biliary tree and urinary tract. While many stones may naturally pass through and out of the patient, some stones are too large to be passed on their own. These stones may become stuck in the biliary tree or urinary tract, thereby requiring medical intervention. A common way to remove stones is with lithotripsy: breaking the stones up into smaller pieces that are then able to be passed naturally out of the patient&#39;s body. One specific example of lithotripsy is electrohydraulic lithotripsy, which employs high energy shock waves to fragment the stones. These shock waves can be generated and targeted at the stone from outside of the patient&#39;s body or with a device that is inserted into the patient&#39;s body—either percutaneously or through a natural body cavity. 
         [0005]    Electrohydraulic lithotripsy uses a shock wave generating device that is inserted into the patient&#39;s body. The device, or probe, is most commonly passed through an accessory channel of a scope or other similar introducer device until the probe is adjacent to the stone. A shock wave is then generated at the tip of the probe towards the stone. Eventually, the stone will fragment and the probe and scope may then be removed while the stone fragments naturally pass through and out of the patient&#39;s body. Alternatively, the fragments may be removed by a vacuum, basket, or other fragment collection device inserted through or with the scope. 
         [0006]    The scope, which is often a cholangioscope, must have an outer diameter small enough to allow it to be safely advanced through a body lumen of a patient. Sometimes, the cholangioscope is advanced through a working channel of a larger duodenoscope that also must have a diameter small enough to allow it be safely advanced through a body lumen of a patient. Since the probe is passed through a working channel of one of these scopes, the outer diameter of the probe must be fairly small. However, these probes are generally quite long, with lengths often exceeding 230 centimeters. Because of the high length to diameter ratio, one common problem associated with electrohydraulic lithotripsy is the buckling or kinking of the probe as it is advanced through the working channel of the scope and into a patient&#39;s body lumen. Kinking and buckling of the probe can be caused by the friction generated between the probe and the working channel of the scope or various structures in the patient&#39;s body lumen. As the physician advances the probe further into the scope, the friction between the scope and probe increases, thus requiring a greater force to further advance the probe. However, as the physician applies more force to the proximal end of the probe, the probe is more likely to kink or buckle, as it cannot withstand a large force due to its small diameter and low strength (or stiffness). When the probe kinks or buckles, the physician may have increased difficulty in advancing the probe towards the stone. The probe may also buckle or kink within the scope as the scope navigates the twists and turns of the patient&#39;s body lumen or at the distal end of the probe as it is advanced past the distal end of the scope. 
         [0007]    Thus, it is desirable to provide a lithotripsy probe that is resistant to kinking and buckling while maintaining a small outer diameter that may be passed through the working channel of a scope. 
       SUMMARY 
       [0008]    In one form of the present disclosure, a medical device is provided. The medical device comprises a probe comprising an elongated shaft comprising a distal end, a proximal end, and an external wall. The probe further comprises at least two conductors extending substantially along a longitudinal length of the probe. The probe also comprises a strengthening element attached to an outer surface of the external wall of the elongated shaft. The probe is configured to slidably move within a working channel of a delivery device. Also, the strengthening element is configured to limit buckling of the probe as a distal portion of the probe is advanced past a deflection point of the delivery device. 
         [0009]    In another form of the present disclosure, a lithotripsy kit is provided. The lithotripsy kit comprises a cholangioscope with a working channel. The lithotripsy kit further comprises a lithotripsy probe comprising an elongated shaft with a distal end, a proximal end, and an external wall. The lithotripsy probe further comprises at least two conductors extending substantially along a longitudinal length of the probe and a strengthening element attached to an outer surface of the external wall of the elongated shaft. Additionally, the lithotripsy probe is slidably movable within the working channel of the cholangioscope. Also, the strengthening element is configured to limit buckling of the probe as a distal portion of the probe is advanced past a deflection point of the cholangioscope. 
         [0010]    In yet another embodiment of the disclosure, a method of modifying a lithotripsy probe is provided. The method comprises providing a lithotripsy probe comprising an elongated shaft. The elongated shaft comprises a distal end, a proximal end, and an external wall. The lithotripsy probe also comprises at least two conductors extending substantially along a longitudinal length of the probe. The method further comprises securing a strengthening element to an outer surface of an external wall of the elongated shaft. The lithotripsy probe is configured to slidably move within a working channel of a delivery device. Further, the strengthening element is configured to limit buckling of the lithotripsy probe as distal portion of the lithotripsy probe is advanced distally past a deflection point of the working channel of the delivery device. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0012]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0013]      FIG. 1  is a drawing of a lithotripsy probe, duodenoscope and cholangioscope inserted into a patient&#39;s duodenum in accordance with the teachings of the present disclosure; 
           [0014]      FIG. 2  is a drawing of a lithotripsy probe with strengthening elements, duodenoscope, and cholangioscope inserted into a patient&#39;s duodenum; 
           [0015]      FIG. 3  is another drawing of a lithotripsy probe with strengthening elements and a duodenoscope inserted into a patient&#39;s duodenum; 
           [0016]      FIG. 4A  is an embodiment of the present invention with a single strengthening element placed on the proximal end of a probe; 
           [0017]      FIG. 4B  is an embodiment of the present invention with a single strengthening element placed along the entire length of a probe; 
           [0018]      FIG. 4C  is an embodiment of the present invention with a single strengthening element placed along the distal end of a probe; 
           [0019]      FIG. 4D  is an embodiment of the present invention with a single strengthening element placed along a central portion of a probe; 
           [0020]      FIG. 4E  is an embodiment of the present invention with two strengthening elements placed along a probe; 
           [0021]      FIG. 5  is a cross-sectional view of a probe with four tubular strengthening elements; 
           [0022]      FIG. 6  is a cross-sectional view of a probe with two tubular strengthening elements; 
           [0023]      FIG. 7  is a cross-sectional view of a probe with a strengthening element wrapped around the entire circumference of the probe; 
           [0024]      FIG. 8  is a cross-sectional view of a probe with a strengthening element wrapped around three quarters of the circumference of the probe; 
           [0025]      FIG. 9  is a cross-sectional view of a probe with a strengthening element wrapped around half of the circumference of the probe; 
           [0026]      FIG. 10  is a cross-sectional view of a probe with a strengthening element wrapped around one quarter of the circumference of the probe; 
           [0027]      FIG. 11  is a cross-sectional view of a probe with a strengthening element with a varying radial thickness; 
           [0028]      FIG. 12  is a cross-sectional view of a probe with one strengthening element; 
           [0029]      FIG. 13  is a cross-sectional view of a probe with two strengthening elements; 
           [0030]      FIG. 14  is a cross-sectional view of a probe with two strengthening elements; 
           [0031]      FIG. 15  is a cross-sectional view of a probe with four strengthening elements; 
           [0032]      FIG. 16  is a cross-sectional view of a probe with eight strengthening elements; 
           [0033]      FIG. 17  is a cross-sectional view of a probe with a strengthening element with a varying thickness; 
           [0034]      FIG. 18  is a cross-sectional view of a probe with a strengthening element with tapered ends; 
           [0035]      FIG. 19  is a cross-sectional view of a probe with two strengthening elements, each with tapered ends; 
           [0036]      FIG. 20  is a side view of a probe with a strengthening element with tapered ends; 
           [0037]      FIG. 21  is a side view of a probe with a strengthening element with a gradual taper from the proximal end to the distal end; 
           [0038]      FIG. 22  is a side view of a probe with a strengthening element with a varying thickness along the longitudinal length of the probe; 
           [0039]      FIG. 23  is an orthographic view of a probe with a curved, rectangular strengthening element; 
           [0040]      FIG. 24  is an orthographic view of a probe with a strengthening element extending around the entire circumference of the probe; 
           [0041]      FIG. 25  is an orthographic view of a probe with a spiral strengthening element; 
           [0042]      FIG. 26  is an orthographic view of a probe with multiple strengthening elements; 
           [0043]      FIG. 27  is an orthographic view of a probe with multiple strengthening elements arranged in a pattern along the length of the probe. 
           [0044]      FIG. 28  is an orthographic view of a probe with multiple strengthening elements arranged in a pattern along the length of the probe; and 
           [0045]      FIG. 29  is an orthographic view of a probe with two spiral strengthening elements. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. It should also be understood that various cross-hatching patterns used in the drawings are not intended to limit the specific materials that may be employed with the present disclosure. The cross-hatching patterns are merely exemplary of preferable materials or are used to distinguish between adjacent or mating components illustrated within the drawings for purposes of clarity. 
         [0047]      FIG. 1  shows a lithotripsy probe  10  inserted into a working channel  13  of a cholangioscope  11 , which is in turn inserted into a working channel  12  of a duodenoscope  14 . In this example, the duodenoscope  14  is inserted into the mouth of a patient and through the digestive track until the distal end  16  of the duodenoscope  14  is near the papilla of Vater  18  in the duodenum  20 . The papilla of Vater  18  is a mound-like structure that extends into the duodenum  20  and serves as the exit point for the common bile duct  22  and pancreatic duct  24 . A stone  26  may be lodged in the common bile duct  22 , and thus the probe  10  must be inserted through the papilla of Vater  18  until the distal end of the probe  10  is near the stone  26 . Before the probe  10  is inserted, the cholangioscope  11  may be inserted through the working channel  12  of the duodenoscope  14  and then pushed through the papilla of Vater  18  until the distal end of the cholangioscope  11  is adjacent to the stone  26 . The probe  10  may then be inserted through a working channel  13  of the cholangioscope  11  until the distal end of the probe  10  is near the stone  26 . Alternatively, the probe  10  can be at least partially preloaded into the working channel  13  of the cholangioscope  11  and the probe  10  and cholangioscope  11  can be advanced through the working channel  12  of the duodenoscope  14  together. Once the distal end of the probe  10  is near the stone  26 , the shock wave energy is applied at the distal tip of the probe  10  and towards the stone  26  which causes the stone  26  to fragment. 
         [0048]    The probe  10 , cholangioscope  11 , and duodenoscope  14  may then be withdrawn from the patient&#39;s body. 
         [0049]    While the probe  10  is at risk of kinking or buckling throughout this procedure, there are several points when the probe  10  is at a significant risk. For example, the probe  10  is at a significant risk of buckling when the distal end of the probe  10  extends past the side port  28  of the duodenoscope  14  ( FIG. 2 ). The cholangioscope  11 , and therefore the probe  10 , are deflected near the side port  28  by an elevator (not shown) within the duodenoscope  14 . The elevator can be manipulated by the physician to control the deflection of the cholangioscope  11  and probe  10  and thus steer the cholangioscope  11  and probe  10  towards the papilla of Vater  18  or other body structure. The elevator may deflect the cholangioscope  11  and probe  10  as much as or more than  90  degrees and through a relatively tight bending radius, which creates a high risk of kinking at the deflection point  30 . Thus, it may be advantageous to attach a distal stiffening (or strengthening) element  32  to the probe  10  near the distal end of the probe  10 . As the probe  10  continues to be advanced towards the stone  26 , a certain length of the probe  10  passes through the deflection point  30 . Therefore, at various stages of the procedure, this certain length of the probe  10  may be at risk of kinking. Thus, it may be ideal for the distal stiffening element  32  to span from the distal end of the probe  10  along and past the portion of the probe  10  that may pass through the deflection point  30 . The distal stiffening element  32  provides added strength to the probe  10  to prevent the probe  10  from buckling or kinking at a point where the probe  10  is susceptible to it. 
         [0050]    Still referring to  FIG. 2 , the probe  10  is also at risk of buckling near the proximal end of the probe  10  as the probe  10  advances past the deflection point  30 . When the distal end of the probe  10  reaches the elevator, the force necessary to further advance the probe  10  through the cholangioscope  11  increases due to the high amount of friction between the working channel  13  of the cholangioscope  11  and the probe  10  at the deflection point  30  and along the entire length of the working channel  13 . Thus, the physician must apply a larger force to the proximal end of the probe  10  than was previously necessary. The portion of the probe  10  that is within the working channel  13  is supported by the low clearance between the walls of the working channel  13  and the probe  10  and thus is unlikely to kink or buckle. However, the proximal portion  34  of the probe  10  that has not yet been advanced into the working channel  13  of the cholangioscope  11  does not have this support to prevent it from buckling. Thus, when the physician applies an increased force to the proximal portion  34  of the probe  10  to advance the probe  10  past the elevator and deflection point  30 , the proximal portion  34  is prone to buckling. Therefore, it may be ideal to attach a proximal stiffening element  36  to the proximal portion  34  of the probe  10 . The proximal stiffening element  36  provides extra support to the proximal portion  34  of the probe  10  to prevent or limit buckling when the physician applies an increased force to advance the probe  10  past the elevator and deflection point  30 . The proximal stiffening element  36  ideally extends along the probe  10  from a point within the working channel  13  of the cholangioscope when the tip of the probe is adjacent to the elevator proximally to at least a point on the probe  10  external the working channel  13  when the distal end of the probe  10  is adjacent to the stone  26 . 
         [0051]    While the probe  10  is most frequently used in conjunction with a cholangioscope  11  as shown in  FIGS. 1 and 2 , the probe  10  may also be used without a cholangioscope  11 . As shown in  FIG. 3 , the probe  10  may be advanced directly through the working channel  12  of the duodenoscope  14  and eventually through the papilla of Vater  18 . In this example, the probe  10  is at a great risk of buckling when the probe  10  is being pushed through the papilla of Vater  18 . Within the papilla of Vater  18  is a sphincter, the sphincter of Oddi (not shown)—a strong muscular valve that is designed to only permit fluid and substances from exiting rather than entering the common bile duct  22  and pancreatic duct  24 . Thus, a large force is required to push the probe  10  through the sphincter of Oddi and into the common bile duct  22 . The physician applies this requisite force to the probe  10  at the proximal portion  34  of the probe  10  that is still located external the scope  14 . However, similar to when the probe  10  is advanced past the elevator, the requisite force is great enough that the proximal portion  34  of the probe  10  may buckle. Thus, the proximal strengthening element  36  may provide added strength to the proximal portion  34  of the probe  10  to prevent it from buckling when the probe  10  is advanced past the sphincter of Oddi. Additionally, the distal strengthening element  32  may extend to the distal tip of the probe  10  to prevent the distal portion of the probe  10  from buckling when the physician is attempting to access the common bile duct  22  through the sphincter of Oddi. 
         [0052]    As described above, whether the lithotripsy probe  10  is advanced directly through the working channel  12  of the duodenoscope  14  or through the working channel  13  of the cholangioscope  11 , the probe  10  is at a greater risk of buckling and kinking at discrete stages. When the cholangioscope  11  is used, the probe  10  is at a greater chance of buckling as it is advanced past the elevator. When the cholangioscope  11  is not used, the probe  10  is at a greater chance of buckling as it is advanced past the elevator and as the distal end of the probe  10  is advanced through the sphincter of Oddi. While the strengthening elements  32 ,  36  may be designed to prevent kinking and buckling at both proximal and distal locations for both of these discrete stages, it may be advantageous or desirable to only prevent kinking for one of the stages. For example, the distal strengthening element  32  may be designed to extend from the distal tip of the probe  10  to a point on the probe  10  that is within the working channel  12  when the distal tip of the probe  10  is in contact with the sphincter of Oddi. The probe  10  is prone to buckling at the portion distal the exit of the working channel since the probe  10  not supported by the working channel  12  as it exits the duodenoscope  14 . Thus, the distal strengthening element  32  may help prevent buckling at this location as the probe  10  is advanced past the sphincter of Oddi. However, in this example the distal strengthening element  32  does not extend along the entire portion of the probe  10  that may be advanced past the elevator and deflection point  30 . Thus, while the location of the distal strengthening element  32  may limit or prevent buckling when the probe  10  is passed through the sphincter of Oddi, the probe  10  may still be prone to kinking near the deflection point  30 . 
         [0053]    Alternatively, the distal strengthening element  32  may be omitted entirely. The outer diameter of the probe  10 , especially the distal portion, is preferably minimized to allow the probe  10  to be advanced through the narrow working channel  12  of the duodenoscope or the working channel  13  of the cholangioscope  11 . Additionally, when the cholangioscope  11  is not used, the physician may find it easier to advance the probe  10  through the sphincter of Oddi without the distal strengthening element  32  since the probe  10  has a small outer diameter. Thus, adding a strengthening element to the distal portion of the probe  10  may be undesirable. However, the proximal portion  34  of the probe  10  may only be partially advanced into the working channel  12  of the duodenoscope  14  or the working channel  13  of the cholangioscope  11  and therefore may not have the same outer diameter restrictions of the rest of the probe  10 . Thus, the proximal strengthening element  36  may be used with less concern for the increased outer diameter the proximal strengthening element  36  may cause. Alternatively, the distal strengthening element  32  may be included and the proximal strengthening element  36  may be omitted entirely. 
         [0054]    The probe and strengthening elements may be used in a variety of applications with varying lengths and designs. In one example, the probe  10  as shown in  FIGS. 1-3  may be around 200 to 300 centimeters in length. The length of the working channel  12  of the duodenoscope  14  may be about 140 to 160 centimeters. The length of the working channel  13  of the cholangioscope  11  may be around 200 to 250 centimeters. This distance between the distal side port  28  and the papilla of Vater  18  is generally around 0.5 to 5 centimeters. Additionally, the probe  10  may extend up to 30 centimeters past the papilla of Vater  18  and into the common bile duct  22 . Therefore, when the distal end of the probe  10  is advanced through the working channel  12  and reaches the deflection point, about 20 to 60 centimeters of the probe  10  may extend outside of the proximal end of the working channel  13  of the cholangioscope  11 . Therefore, it may be ideal to make the proximal strengthening element at least 20 to 60 centimeters in length, thus ensuring that the proximal portion of the probe  10  does not kink or buckle. Additionally, since the distance between the papilla of Vater  18  and the distal side port  28  may be around 0.5 to 5 centimeters, it may be ideal to make the distal strengthening element  32  20 to 40 centimeters in length. 
         [0055]      FIGS. 4A through 4E  show several exemplary placements of a strengthening element  40  on the probe  10 . The probe  10  has a proximal end  42  and a distal tip  44 . In  FIG. 4A , a single strengthening element  40  extends from the proximal end  42  distally along a portion of the length of the probe  10 . In  FIG. 4B , a single strengthening element  40  extends along the entire length of the probe  10 . In  FIG. 4C , a single strengthening element  40  extends from the distal tip  44  proximally along a portion of the length of the probe  10 . In  FIG. 4D , a single strengthening element  40  extends along a central portion of the probe  10 . In  FIG. 4E , two strengthening elements  40  are attached to the probe  10 . Because the outer diameter of the probe  10  is increased with the addition of the strengthening element  40 , it may be advantageous to add the strengthening element  40  to only a limited length of the probe  10 . These are just five examples of the potential placement of the strengthening element  40  along the probe  10 . Any number of locations are contemplated, including the use of multiple strengthening elements. 
         [0056]    The strengthening elements are ideally placed on the outer surface of the external wall of the probe. While the strengthening elements may also be placed within the outer wall of the probe, there may be several disadvantages. The probe is frequently designed with conductive wires that run along the length of the probe to the distal end. These conductive wires carry the electrical energy that results in a high voltage spark and the accompanying shockwave at the distal end of the probe. For the probe to operate effectively, the conductive wires must be properly separated and insulated along the entire length of the probe, thereby only allowing electrical contact between the conductive wires at the distal end of the probe. Since the strengthening elements are frequently made of a conductive material, there is a risk that the strengthening elements will interfere with the conductive wires. For example, the strengthening elements may inadvertently contact one or both of the conductive wires, causing the conductive wires to short circuit, thus rendering the probe ineffective. Additional interference issues may occur even if the conductive wires remain properly insulated from the strengthening elements. If the strengthening elements are within the outer wall of the probe, they are closer to the conductive wires and therefore are at a greater risk of causing interference or short circuiting the conductive wires. Placing the strengthening elements on the outer surface of the probe&#39;s external wall reduces or eliminates this concern. 
         [0057]    The strengthening elements may be comprised of various biocompatible materials that are capable of adding strength and stiffness to the probe  10 , including, but not limited to: peek beading, stainless steel, various metal alloys, and other stiff or flexible polymers. In some embodiments, as shown in  FIGS. 4A through 4E , the strengthening element  40  may be made of nitinol. In this embodiment, the strengthening elements  40  are attached to an external wall of the probe  10 ; however, the strengthening elements  40  may also be placed within the external walls of the probe  10 . An outer covering, such as shrink tubing  43 , may be used to secure the strengthening element  40  to the probe  10 . The outer covering may be comprised of PTFE shrink, PET shrink, or other similar materials. Alternatively, the strengthening element  40  may be attached to the probe  10  using casting, molding, adhesives, or similar methods. 
         [0058]    In addition to the various potential locations of the strengthening elements along the length of the probe  10 , various shapes and patterns may be used to minimize the profile of the strengthening elements or maximize their effectiveness. The following figures and descriptions are merely exemplary in nature and any variety of patterns or shapes are contemplated in this disclosure. 
         [0059]      FIGS. 5 and 6  show two potential cross sections of the probe  45  and the strengthening elements  46 .  FIG. 5  shows the probe  45  with four strengthening elements  46  and  FIG. 6  shows the probe  45  with two strengthening elements  46 . In this example shrink wrap tubing  47  is wrapped around the strengthening elements  46  to secure the strengthening elements  46  to the probe  45 , however various other methods may be used as discussed previously. Additionally, any number of strengthening elements  46  may be used and may be evenly spaced around the cross-section of the probe  45  or with other patterns. The strengthening elements  46  may have varying diameters to increase or decrease the amount of strength added to the probe  45  as desired. Further, the strengthening elements  46  may have various shapes, including tubular, cylindrical, rectangular, etc. The strengthening elements  46  may extend along the entire length of the probe  45  or along just a portion of it. When multiple strengthening elements  46  are used, the strengthening elements may span different lengths of the probe  45 . 
         [0060]      FIGS. 7-10  show various strengthening elements with circular cross-sections. In these Figures, and the additional Figures following, the shrink wrap tubing or other bonding method is omitted to more clearly show the various potential designs of the strengthening elements. In  FIG. 7 , the strengthening element  52  extends around the entire circumference of the probe  50 . In  FIG. 8 , the strengthening element  56  extends around three-quarters of the circumference of the probe  54 . In  FIG. 9 , the strengthening element  60  extends around about half of the circumference of the probe  58 . In  FIG. 10 , the strengthening element  64  extends around one-quarter of the circumference of the probe  62 . These designs are merely examples, and the strengthening element may extend around any portion of the circumference. Additionally, the strengthening elements may extend along the entire length of the probe or along only a portion of the probe. Additionally, the strengthening elements may have varying radial thicknesses to achieve greater strength or a lower radial profile as desired. 
         [0061]      FIG. 11  shows one example of a varying diameter strengthening element  68 . The mid-point of the strengthening element  68  has a large radial thickness which gradually thins towards each end of the strengthening element  68 .  FIG. 12  shows a narrow strengthening element  72  attached to the probe  70 .  FIG. 13  uses two narrow strengthening elements  76 ,  78  attached to the probe  74 .  FIG. 14  uses two wider strengthening elements  82 ,  84 . Alternatively,  4  or more strengthening elements may be used of varying cross-sectional lengths. For example,  FIG. 15  shows a probe  86  with four strengthening elements  88 ,  90 ,  92 ,  94 . Also,  FIG. 16  shows a probe  96  with eight strengthening elements  98 ,  100 ,  102 ,  104 ,  106 ,  108 ,  110 ,  112 . Any number of additional or fewer strengthening elements can be added to the design as desired, including spacing the strengthening elements in a non-symmetrical fashion. 
         [0062]      FIG. 17  shows a single strengthening element  116  that wraps around the entire circumference of the probe  114 . However, the strengthening element  116  includes a varying outer diameter, such that several bumps  118 ,  120 ,  122 , and  124  with larger outer diameters than the rest of the strengthening element  116  are formed. Various other patterns using a varying outer diameter of the strengthening element  116  may be employed.  FIGS. 18 and 19  show strengthening elements with a taper at each edge.  FIG. 18  has a single strengthening element  128  that tapers at the edge and  FIG. 19  has two strengthening elements  132 ,  134  that taper at their respective edges. 
         [0063]      FIGS. 20-22  show several exemplary side views of the probe and strengthening element.  FIG. 20  shows the strengthening element  138  with a taper on each longitudinal end of the strengthening element  138 .  FIG. 21  shows a strengthening element  142  that tapers from one end of the probe  140  towards the other end.  FIG. 22  shows a strengthening element  146  with a varying thickness along the longitudinal length of the strengthening element  146 . These variations in the longitudinal lengths and diameters along the longitudinal lengths can be combined with any of the aforementioned cross-sectional designs. 
         [0064]      FIGS. 23-29  show orthographic views of exemplary strengthening element designs.  FIG. 23  shows a curved strengthening element  150  that extends around a portion of the circumference of the probe  148  and along only a limited length of the probe  148 .  FIG. 24  shows a strengthening element  154  that extends around the entire circumference of the probe  152  and along a limited length of the probe  152 . In either of these examples, the strengthening elements could be modified to extend along the entire length of the probe, or multiple strengthening elements of the same shape and length may be used along various portions of the probe. 
         [0065]      FIG. 25  shows a strengthening element  158  that is wrapped in a spiral pattern around the probe  156 . The strengthening element  158  may have a cylindrical, rectangular, tubular, or other cross-section. Additionally, the strengthening element  158  may be wrapped in a tighter spiral to increase the effectiveness of the strengthening element  158  or in a looser spiral as desired. While the strengthening element  158  in this example extends along the entire length of the probe  156 , the strengthening element  158  may be designed to only extend along a portion of the probe  156 . Additionally, multiple spiral strengthening elements may be used, such as shown in  FIG. 29 . In  FIG. 29 , one strengthening element  184  is wrapped around the probe  182  in a clockwise direction while the other strengthening element  186  is wrapped around the probe  182  in a counter-clockwise direction. In this embodiment the two strengthening elements  184 ,  186  are wrapped around the probe  182  in spirals of similar tightness, but they may be varied as desired. Alternatively, two or more spiral strengthening elements may be wrapped around the probe in the same direction, with the tightness or looseness of the spirals varying or remaining constant. 
         [0066]      FIG. 26  shows a probe  160  with multiple strengthening elements  162 ,  164 ,  166 ,  168 . This embodiment shows one example of a pattern of multiple, straight strengthening elements arranged along the length of the probe  160 . Various other placement patterns may be used as well, including non-uniform placement and shape of the various strengthening elements. 
         [0067]      FIG. 27  shows a probe  170  with two strengthening elements  172 ,  174  wrapped circumferentially around the probe  170 . More than two, or only one, strengthening elements may be used in the arrangement shown in  FIG. 27 .  FIG. 28  shows a probe  176  with two strengthening elements  178 ,  180  wrapped around a portion of the circumference of the probe  176 . More than two, or only one, strengthening elements may be used in the arrangement shown in  FIG. 28 . 
         [0068]    While the present disclosure describes the invention in terms of lithotripsy probe used during a biliary procedure, the improved probe may be used in any lithotripsy procedure to prevent kinking and buckling of the probe when inserted into a patient. Further, the anti-kinking and buckling improvements may be used with a variety of other medical devices unrelated to lithotripsy, such as catheters used in a variety of medical procedures. Also, the improvements described above may be used in a variety of non-medical applications. 
         [0069]    The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.