Patent Abstract:
A sphincterotome including a cutting wire may be configured such that, when activated, the cutting wire assumes a desired cutting position at or near the “12 o&#39;clock” position or any other desired angular configuration. A sphincterotome may have controlled bending characteristics. A distally located micromachined hypotube may, in some instances, provide desired bending characteristics to a sphincterotome.

Full Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/978,336, filed Oct. 8, 2007, the entire disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention pertains generally to medical devices and more particularly to medical devices such as sphincterotomes. 
     BACKGROUND 
     In procedures such as endoscopic sphincterotomy, a sphincterotome may be used in conjunction with an endoscope to provide surgical cutting inside of a patient. Exemplary sphincterotomes are disclosed in commonly assigned U.S. Pat. Nos. 5,547,469 and 5,868,698 to Rowland et al., the disclosures of which are incorporated herein by reference. The sphincterotome may, for example, be used to partially cut open the sphincter muscle for treatment such as removal of common bile duct stones forming an obstruction. A sphincterotome may include a cutting wire that can be activated by bending the sphincterotome, thereby permitting the cutting wire to extend from the sphincterotome. 
     However, when activating the cutting wire, it may be difficult to control the exact positioning of the cutting wire. In some instances, it may be desirable to position the activated cutting wire in an angular configuration commonly referred to in the art as the “12 o&#39;clock” position, or in any other desirable angular configuration. 
     There remains a need, therefore, for an improved sphincterotome that is configured such that, when activated, the cutting wire assumes a desired cutting position at or near the “12 o&#39;clock” position, or any other desired angular configuration. A need remains for an improved sphincterotome with controlled bending characteristics. 
     SUMMARY 
     The invention pertains to an improved sphincterotome that is configured such that, when activated, the cutting wire assumes a desired cutting position at or near the “12 o&#39;clock” position or any other desired angular configuration. In some cases, activating the cutting wire may include application of an electrical current, but this is not required. The invention pertains to an improved sphincterotome having controlled bending characteristics. 
     Accordingly, an illustrative but non-limiting example of the invention may be found in a sphincterotome having an elongate shaft and a cutting element lumen extending through the elongate shaft. A micromachined hypotube may be disposed within a distal region of the elongate shaft. A cutting element may be disposed within the cutting element lumen such that an exposed portion of the cutting element is disposed exterior to the micromachined hypotube. 
     Another illustrative but non-limiting example of the invention may be found in a sphincterotome that is movable between a cutting position and a non-cutting position. The sphincterotome includes an elongate shaft that defines a cutting wire lumen extending within the elongate shaft. A cutting wire may be disposed within the cutting wire lumen. The sphincterotome includes apparatus or structure disposed exterior to the elongate shaft that is configured to limit a bending plane of the elongate shaft. 
     Another illustrative but non-limiting example of the invention may be found in a sphincterotome that has an elongate shaft that defines a cutting wire lumen. A cutting wire may be disposed within the cutting wire lumen. A distal region of the elongate shaft may be configured to have a greater flexibility in an activating bending plane and a lesser flexibility in an orthogonal bending plane. 
     The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The Figures, Detailed Description and Examples which follow more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: 
         FIG. 1  is a view of a sphincterotome in accordance with an illustrative but non-limiting example of the invention; 
         FIG. 2  is a cross-sectional view taken along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view taken along line  3 - 3  of  FIG. 1 ; 
         FIG. 4  is a view of a micromachined hypotube that may be incorporated into the sphincterotome of  FIG. 1 , in accordance with an illustrative but non-limiting example of the invention; 
         FIG. 5  is a top view of a distal portion of the sphincterotome of  FIG. 1 , incorporating the micromachined hypotube of  FIG. 4  in accordance with an illustrative but non-limiting example of the invention; and 
         FIG. 6  is a side view of a distal portion of the sphincterotome of  FIG. 1 , incorporating the micromachined hypotube of  FIG. 4  in accordance with an illustrative but non-limiting example of the invention, shown in a curved configuration. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
     All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure. 
     The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The drawings, which are not necessarily to scale, depict illustrative embodiments of the claimed invention. 
     The present invention generally pertains to a sphincterotome  10 , as illustrated in  FIG. 1 . The sphincterotome  10  can be seen as including a proximal section  12  and a distal section  14 . A handle  16  is disposed within the proximal section  12  and an elongate shaft  18  extends distally therefrom. The handle  16  may be formed of any suitable metallic or polymeric material, such as those discussed hereinafter. The elongate shaft  18  itself has a distal region  20  defining a distal end  22  and a proximal region  24  defining a proximal end  26 . In some instances, it is contemplated that part of the elongate shaft  18  may undergo processing that may impart a curve or bias thereto, although this is not required. The elongate shaft  18  may be formed of or include any suitable polymeric material. In some cases, the elongate shaft  18  may include portions made from or including polytetrafluoroethylene, better known as TEFLON®. 
     A hub  26  may be disposed within the proximal region  24  of the elongate shaft  18 . In some instances, if desired, the hub  26  may include a first hub portion  28  having a side port  30  that may be used to gain fluid access to an interior of the elongate shaft  18 . The hub  26  may also include a second hub portion  32  that may, if desired, provide guidewire access to the interior of the elongate shaft  18  via a guidewire port  34  that is provided within the second hub portion  32 . The elongate shaft  18  can be seen as extending distally to a distal end  22  of the elongate shaft  18 . The elongate shaft  18  may be considered as including the hub  26 , first hub portion  28  and second hub portion  32 . The hub  26  and defined portions thereof may be formed of any suitable polymeric material. 
     As noted, the elongate shaft  18  includes an interior.  FIGS. 2 and 3 , which are cross-sections taken through the elongate shaft  18 , provide illustrative but non-limiting examples of an interior of the elongate shaft  18 . In  FIG. 2 , which is taken through a relatively proximal portion of the elongate shaft  18 , it can be seen that the elongate shaft includes a first lumen  36  and a second lumen  38 . In some instances, the elongate shaft  18  may include only one lumen, or may include three or more lumens. 
     In the illustrated embodiment, the first lumen  36  may, for example, be a guidewire lumen in communication with the guidewire port  34  disposed within hub  32 . The second lumen  38  may, if desired, accommodate a cutting element  40 . The cutting element  40  may extend from the handle  16  to a position within the distal region  20  of the elongate shaft  18 . In some instances, the cutting element  40  may be a cutting wire, as known in the art. In some cases, the cutting element  40  may be a stranded or braided wire. 
       FIG. 3  is a cross-section taken through a relatively distal portion of the elongate shaft  18 . In this view, only a single lumen  42  is present. In some cases, the first lumen  36  and the second lumen  38  may merge into a single lumen  42 . In some cases, the second lumen  38  (through which the cutting element  40  is disposed) may terminate at a position proximal of where this cross-section is taken as the cutting element  40  itself may extend external to the shaft or terminate proximal of the cross-section point. In other cases, the elongate shaft  18  may include one, two, three or more lumens that extend all the way to the distal end  22  of the elongate shaft  18 . In some cases, the elongate shaft  18  may be configured to provide rapid exchange capability and thus may include a short guidewire lumen (not illustrated) extending through a distal portion of the elongate shaft  18 . 
     Returning to  FIG. 1 , it should be noted that the cutting element  40  (seen in  FIG. 2 ) has a distal end (discussed later with respect to  FIGS. 5 and 6 ) and a proximal end  44 . In some cases, the proximal end  44  may be secured to the handle  16 . More particularly, the handle  16  may include a stationary portion  46  and a movable portion  48 . The stationary portion  46  may be secured to the elongate shaft  18  while the proximal end  44  of the cutting element  40  may be secured to the movable portion  48 . The movable portion  48  may be slidingly disposed on the stationary portion  46 . 
     The stationary portion  46  may, if desired, include a thumb ring  50  while the movable portion  48  includes one or more finger rings  52 . Thus, a physician or other professional may activate the sphincterotome  10  by holding the thumb ring  50  in his or her thumb and using their fingers to pull the finger rings  52  (and thus the movable portion  48 ) proximally. 
     The handle  16  may also, if desired, include a connector block  80  that may be used to provide communication between the cutting element  40  and a RF heating source, as is known in the art, in order to energize the cutting element  40 . 
     The distal region  20  of the elongate shaft  18  may, as illustrated, include one or more marker bands  54 . The marker bands  54 , if present, may be formed of any suitable radiopaque material and may have any appropriate dimensions and/or axial spacing, as desired. In some cases, the marker bands  54  may be visually evident during use, and therefore in some instances, the marker bands  54  may not be formed of a radiopaque material but may instead simply be applied using a material of a different color. The marker bands  54  may aid in positioning the sphincterotome  10  during a procedure. 
     The distal region  20  of the elongate shaft  18  also includes elements not expressly illustrated in  FIG. 1 . In particular,  FIG. 4  provides a view of a micromachined hypotube  56  that may be disposed within or about at least a portion of the distal region  20  of the elongate shaft  18 . The micromachined hypotube  56  has a proximal portion  58  defining a proximal end  60  and a distal region  62  defining a distal end  64 . The micromachined hypotube  56  has a first side  66  and a second side  68 . The first side  66  may include a first plurality of slots  70  while the second side  68  includes a second plurality of slots  72 . At least some of the first plurality of slots  70  may be parallel. At least some of the second plurality of slots  72  may be parallel. 
     Each of the first plurality of slots  70  and each of the second plurality of slots  72  extend only partially around the circumference of the micromachined hypotube  56 . In some instances, as illustrated, each of the first plurality of slots  70  and each of the second plurality of slots  72  are at least substantially equally sized in length and width, and start and stop along common lines. While not illustrated, it is contemplated that the relative axial spacing and/or width of some of the slots within the first plurality of slots  70  and/or the second plurality of slots  72  may vary in order to provide customized flexibility control. 
     It can be seen that the micromachined hypotube  56  will have a greater flexibility in a first bending plane in which, for example, at least some of the first plurality of slots  70  open while at least some of the second plurality of slots  72  close. Conversely, the micromachined hypotube  56  will have a reduced flexibility in a second bending plane that is orthogonal to the first bending plane. It can be seen that the first bending plane may be referred to as an activating bending plane while the second bending plane might be referred to as an orthogonal bending plane. 
     Each slot within the first plurality of slots  68  and the second plurality of slots may be formed to be at least largely rectangular in shape. In some instances, at least some of the slots may not extend all the way through micromachined hypotube  56 . Each slot may be formed using any suitable technique, such as saw cutting, a laser, or even by electrical discharge machining (EDM). Additional suitable techniques include chemical etching and abrasive grinding. 
     The micromachined hypotube  56  may be formed of any suitable polymeric or metallic material. In some cases, the micromachined hypotube  56  may be formed of a suitably stiff polymer such as carbon fibers, liquid crystal polymers, polyimide, and the like. In some instances, the micromachined hypotube  56  may be formed of a metallic material such as stainless steel or a nickel-titanium alloy such as Nitinol or other metallic or polymeric shape-memory material. The micromachined hypotube  56  may include a combination of metal tubes and polymer tubes, if desired. In some cases, the micromachined hypotube  56  may be formed as an integral part of the elongate shaft  18 , or in some instances, the slots may instead be formed within the elongate shaft  18  itself. 
     The micromachined hypotube  56  may be formed having any desired length, width, material thickness, and slot size as required to satisfy the requirements of any particular application. Additional details concerning micromachined hypotube  56 , including the manufacture thereof, can be found, for example, in U.S. Pat. No. 6,766,720 and U.S. Patent Publication No. 2004/0181174A2, each of which are incorporated by reference herein to the extent that they do not conflict with the present disclosure. 
       FIGS. 5 and 6  clarify operation of the sphincterotome  10 . In  FIG. 5 , the micromachined hypotube  56  has been disposed about or within the distal region  20  of the elongate shaft  18 . In some cases, the micromachined hypotube  56  may be disposed about an exterior of the elongate shaft  18 . If desired, and to electrically isolate the micromachined hypotube  56  from the cutting element  40 , a polymeric coating or sheath may be applied to the micromachined hypotube  56 . In some instances, the micromachined hypotube  56  may be molded within the polymeric or other material forming the elongate shaft  18 , as desired. 
     The cutting element  40  includes an exposed cutting portion  74  that extends from a distal end  76  of the cutting element  40  to a port  78  disposed within the elongate shaft  18 . As illustrated, the distal end  76  of the cutting element  40  is secured directly to the distal region  62  of the micromachined hypotube  56 . In some cases, it is contemplated that the cutting element  40  could instead pass through an aperture (not illustrated) or rest within a slot or channel within the micromachined hypotube  56  such that the distal end  76  of the cutting element  40  could instead be anchored directly to the elongate shaft  18 . 
     As noted previously, the cutting element  40  extends proximally to the handle  16 . The port  78  is an aperture formed within the wall of the elongate shaft  18  and may, if desired, include reinforcing structure (not illustrated). In  FIG. 5 , the exposed cutting portion  74  can be seen to be in a non-cutting position in which the exposed cutting portion  74  of the cutting element  40  is at least substantially parallel with the elongate shaft  18 . 
     In  FIG. 6 , however, the exposed cutting portion  74  of the cutting element  40  is in a cutting position in which the exposed cutting portion  74  of the cutting element  40  has pulled away from the elongate shaft  18  as a result of proximal movement of the movable portion  48  relative to the stationary portion  46 . It can be seen that the micromachined hypotube  56  provides at least part of the distal region  20  with a smooth curvature that is free of kinks. 
     As discussed above, the micromachined hypotube  56  is configured to be more flexible in a first bending plane and less flexible in a second, orthogonal bending plane. The micromachined hypotube  56  may be secured to the elongate shaft  18  oriented in such a way that when a tensile force is applied to the cutting element  40 , the first bending plane corresponds to the “12 o&#39;clock” direction. As a result, the sphincterotome  10  will reliably or predictably bend in a desired direction. 
     In some instances, it is contemplated that the cutting element  40  may not actuate in exactly a desired direction or plane. This may occur, for example, as a result of manufacturing tolerances, interference from the anatomy, influence from an endoscope, and the like. Nevertheless, the sphincterotome  10  will, as a result of micromachined hypotube  56 , reliably and repeatedly bend in a desired plane. 
     The devices described herein may include a variety of different materials. These materials may include metals, metal alloys, polymers, metal-polymer composite, and the like, or any other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium alloy such as linear-elastic or super-elastic nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having a composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum 0.15% Si), hastelloy, monel 400, inconel 825, or the like; other Co—Cr alloys; platinum enriched stainless steel; or other suitable material. 
     Some examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example, DELRIN® available from DuPont), polyether block ester, polyurethane, polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene/poly(alkylene ether) phthalate and/or other polyester elastomers such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA), silicones, polyethylene (PE), Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly paraphenylene terephthalamide (for example, KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. 
     In addition, the devices described herein may also be doped with or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of filtering device in determining their location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, molybdenum, palladium, tantalum, tungsten or tungsten alloy, plastic material loaded with a radiopaque filler, and the like. 
     The invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the invention can be applicable will be readily apparent to those of skill in the art upon review of the instant specification.

Technology Classification (CPC): 0