Abstract:
A tool for scrubbing, removing tissue from the medullary cavity or joint cavity of a bone or removing cartilage and/or cortical bone from a joint cavity has a proximal end, a distal end, and a cannula extending therethrough. The distal end includes at least one scraping surface and/or cutting surface to soften marrow in the medullary cavity or joint cavity as the scraping and/or cutting surface(s) are rotated or otherwise moved relative to the medullary cavity or joint cavity. When used, the tool may be attached to a drill and the cannula receives a K-wire previously inserted into the medullary or joint cavity. The drill rotates the tool around the K-wire and pushes the tool over the K-wire into the medullary cavity or joint cavity.

Description:
FIELD OF THE INVENTION 
       [0001]    The present disclosure generally relates to medical devices. More particularly, the disclosure relates to tools suitable for preparing a joint for fusion with a percutaneous method of cartilage destruction. 
       BACKGROUND OF THE INVENTION 
       [0002]    For various reasons, it may be desirable to destroy or remove cartilage from the joint area of a bone. For example, such procedures are often employed in the treatment of hand or foot injuries during the process of joint fusion to facilitate the healing of a joint fusion. Joint fusion is indicated for unstable or painful joints. The process of joint fusion involves removal or destruction of the smooth cartilage lining of a joint followed by fixation of the raw ends of the bone to each other with the intent to have the bone ends heal and form a solid, non-movable, bone construct that is no longer unstable or painful. 
         [0003]    A typical method of performing joint cartilage removal involves creating and incision or open arthrotomy and mechanically removing the joint cartilage with a burr, or biting or cutting instrument. Usually a rongeur, a type of biting tool, is used. Sometimes in addition to cartilage, subcortical hard bone is also removed. Alternatively, destruction of the cartilage in some form as opposed to removal of cartilage may also be satisfactory. Although this technique works relatively well, the method is relatively cumbersome and time consuming, requiring a large exposure or access to the joint. Accordingly, improved techniques and tools for joint preparation and cartilage removal or destruction when fusions are performed are desired. 
         [0004]    The present invention allows the safe insertion of a cartilage destroyer into a joint with percutaneous techniques. The guidewire controls the device preventing errant travel of the device and its sharp cutting edges providing for safe percutaneous cartilage destruction. 
       SUMMARY OF THE INVENTION 
       [0005]    The present disclosure generally relates to tools and techniques for removing or destroying joint cartilage during joint fusion procedures. More particularly, the disclosure relates to tools that include one or more scraping and/or cutting surfaces to break up and/or destroy or remove cartilage in a joint and to methods of using the tools. 
         [0006]    A tool for destroying or removing cartilage from bone includes a proximal end, a distal end, and a cannula extending through the tool. The distal end includes at least one scraping and/or cutting surface to break up and/or soften the cartilage in the joint as the scraping and/or cutting surface is rotated or otherwise moved within the cavity. The proximal end can include a section that can be received by a device, such as a drill, that can be used to cause the tool to rotate. The cannula can be configured to receive a guide wire, such as a K-wire, to help guide the distal end of the tool towards and into the joint cavity to be scrubbed or arthrolysed. 
         [0007]    When used, the tool is preferably attached to a drill and the cannula has received an end of a guide wire, wherein a portion of the guide wire has been inserted into the joint cavity. The drill rotates the tool around the guide wire and can be used to push the tool over the guide wire and into the joint cavity. Once the tool is inserted into the joint cavity, the drill can be used to move the tool along an axis of the guide wire into the cavity as well as cause the tool to rotate within the cavity. 
         [0008]    Procedures using a tool as described herein can be less cumbersome and less time consuming, less traumatic compared to traditional medullary cavity scrubbing techniques. The device as designed preferably provides a lead cutting surface suitable for trans-cutaneous or percutaneous insertion into a joint though a small skin hole 
         [0009]    The device being of a cannulated design allows for controlled delivery of the sharp cutting lead end of the device into and out of the joint, thus providing for cartilage destruction, but preventing creep of the device into other areas such as nerves and tendons 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective, side view of a tool according to aspects of the invention. 
           [0011]      FIG. 2  is a different, perspective, side view of the tool according to aspects of the invention. 
           [0012]      FIG. 3  is a side view of the tool of  FIGS. 1 and 2 . 
           [0013]      FIG. 4  is a cross-sectional side view of the tool of  FIG. 3  taken along lines E-E. 
           [0014]      FIG. 5  illustrates a distal section of the tool according to aspects of the invention. 
           [0015]      FIG. 6  is an end view of the distal tip of the distal section of a tool according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0016]    The description of exemplary embodiments of the present invention provided below is merely exemplary and is intended for purposes of illustration only; the following description is not intended to limit the scope of the invention disclosed herein. Moreover, recitation of multiple embodiments having stated features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the stated features. 
         [0017]    The present disclosure describes medical tools and systems that are suitable for use in treatment of joints, and particularly for treatments including joint fusion or arthrodesis, such as arthrodesis of phalanges. For example, exemplary devices and systems described herein are suitable for treatment of a distal interphalangeal (DIP) joint, and other joints such as for fusion and the scrubbing of the joint prior to implantation of another device, such as a bone screw. The devices and systems are conveniently described below in connection with such treatment; however, unless otherwise noted, tools and systems described herein are not limited to such applications. 
         [0018]    Turning now to the figures,  FIGS. 1-4  illustrate a tool  10  in accordance with aspects of the invention. Tool  10  includes at least a proximal section  50  and a distal section  100 , and preferably includes an intermediary section  200 . In the illustrated example, a cannula  300  spans an interior length of tool  10 . In accordance with other embodiments, cannula  300  spans at least a portion of tool  10 . Cannula  300  can allow a portion of a guide wire, discussed in more detail below, to be received by at least a portion or all of tool  10 . 
         [0019]    Tool  10  can be used to remove cartilage or soften and/or break up marrow within a medullary cavity of a bone. The breaking up/softening of the marrow material can facilitate attachment of devices, such as screws or other forms of anchors, to the bone. Removal of cartilage from a joint can facilitate joint fusion 
         [0020]    In the illustrated example, proximal section  50  includes a section  52 , a proximal tip  54 , and a distal end  56 . Proximal tip  54  can be configured to be received by a driver. Exemplary drivers include a variable or single speed electric drill. Proximal end  54  can also be configured to attach to a hand held driving device. Proximal tip  54  can be shaped as a truncated cone, with a portion of cannula  300  spanning at least partially, and in some cases, entirely through proximal tip  54 . The truncated conical shape can facilitate insertion of proximal tip  54  into the driver. Distal end  56  can include a tapered section  60 —e.g., in the form of a truncated cone, wherein a distal end  62  of tapered section  60  has a width that is less than a width of section  52 . Section  52  can include a cylindrical or other suitable shape. A driver can engage section  52  to cause tool  10  to rotate about an axis A. A length of proximal section  50  can be about 30 percent or more, about 40 percent or more, or about 50 percent of more of the total length of the tool. A length of proximal section  50  can range from, for example, about 20 to about 30 mm, about 15 to about 40 mm, or about 10 to about 50 mm. A width of proximal section  50  can range from about 2 to about 4 mm, about 2 to about 6 mm, or be about 3.18 mm. 
         [0021]    Distal section  100  includes one or more scraping surfaces  102  to scrape material within a medullary cavity of a bone or joint cavity. Scraping surface  102  can be formed at one or more edges of a portion of distal section  100 . In the illustrated example, surfaces  108  of distal end  100  form a triangular prism, having a plurality, namely three edges that form scraping surface  102 . In this case, a cross section of the portion of distal section  100  that scrapes or scrubs the medullary cavity or joint cavity has a triangular cross section. Other cross sections, such as square and other polygonal shapes, or overall flat shapes are also contemplated by this disclosure. A proximal end of distal section  100  can be tapered, as illustrated, to form a transition area between intermediary section  200  and surfaces  108  and edges  102 . Distal section  100  can include any suitable number of scraping surfaces  102 . By way of example, distal section  100  includes 1, 2, 3, 4, 5, 6, 7, or 8 or more scraping surfaces. A length of scraping surfaces  102 , from proximal end  104  to a distal end  106  can range from about 5 to 6 mm, about 4 to 7 mm, or be about 5.09 mm. The width and length will vary and be relative to the joint cavity contemplated. For instance, for larger joints of the foot, a larger device is contemplated. A width of the scraping surface  102  of distal end  100  can be the same as the width of proximal section  50 . 
         [0022]    Distal section  100  can also include a head or tip  110  including one or more cutting surfaces  112 . In the illustrated example, head  110  includes three cutting surfaces  112 . Head  110  can be tapered from a relatively large width at a proximal end  118  (e.g., a width of scraping surfaces  102 ) to a distal end  116  (a width of cutting surfaces  112 ). For example, as shown in  FIG. 5 , head  110  can include one or more surfaces  114  that are tapered at an angle of about twenty degrees, or from about ten to about 30 degrees, or from about 5 to about 45 degrees. Cutting surfaces  112  can be further sharpened. In the illustrated example, head  110  has a pyramidal shape, with surfaces  114  that terminate at distal end  116  at cannula  300  and at proximal end  118  at distal end  106  of scraping surfaces  102  and surfaces  108 . In this case, cutting surfaces  112  include a triangular shape. A length of head  110  can range from about 0.5 to about 10 mm, about 2 to about 8 mm, or be about 2.61 mm. 
         [0023]    Intermediary section  200  spans between proximal section  50  and distal section  100 . More particularly, intermediary section  200  can span between proximal end  104  of distal section  100  and distal end  56  of proximal section  50 . Intermediary section  200  can be in the form of a cylinder. A width (e.g., outer diameter) of intermediary section  200  can be less than a width of distal section  100  and/or less than a width of proximal section  50 . By way of examples, a width of intermediary section  200  ranges from about 1 mm to 3 mm, about 1 mm to 2 mm, or be about 1.57 mm. A length of intermediary section can range from about 2 to 25 mm, about 5 to 20 mm, or be about 12.64 mm. 
         [0024]    As noted above, cannula  300  can extend through the entire length of tool  10 . A diameter of cannula  300  can range from about 0.25 to 1 mm, about 0.5 to 1 mm, or be about 0.75 mm. The cannula can be configured to receive a guide wire, such as a 0.025″ K-wire. The guide wire can be used to guide tool  10  into and through a medullary cavity. In some forms, the device may not have an internal cannula. 
         [0025]    Tool  10  and sections  50 ,  100 , and  200  can be formed of a variety of materials. By way of example, tool  10  is formed of 304 stainless steel. Tool  10  can be of unitary construction, or can be formed of multiple sections. For example, distal section  100  (e.g., a tip  120  of distal section  100 ) can be attachable to intermediary section  200  (e.g., to distal end  204  of intermediary section  200 ). Similarly, intermediary section  200  can be attachable (e.g., threadingly engaged) at a proximal end  202  to distal end  56  of proximal section  50 . An overall length of tool  10  can range from about 25 to 75 mm, about 40 to about 60 mm, or be about 47.4 mm. 
         [0026]    To use tool  10 , a guide wire can be inserted into a medullary cavity to be scrubbed. Tool  10 , which can be fitted onto a driver, can be inserted over the guide wire. The driver can be used to push tool  10  over the guide wire and into the medullary or joint cavity. The driver can further cause tool  10  to rotate and/or move along an axis of the medullary cavity, thereby causing a scraping (with surfaces  102 ) and cutting (with surface  112 ) of marrow material within the medullary cavity. 
         [0027]    Non-limiting specific examples of devices according to the invention follow: 
         [0000]    1. A tool for scrubbing the medullary cavity of a bone or joint cavity, the tool comprising a body having:
       (a) a distal section having a scraping surface to scrape a medullary cavity in order to soften marrow within the medullary cavity;   (b) a proximal section; and   (c) a cannula extending through the tool.
 
2. A tool for scrubbing the medullary cavity or joint of a bone, the tool comprising a body having:
   (a) a distal section having one or more cutting surfaces to soften marrow within a medullary cavity or remove cartilage and cortical bone from a joint cavity;   (b) a proximal section; and   (c) a cannula extending through at least a portion of the tool.
 
3. The tool of any of examples 1-2 wherein the proximal section has a proximal tip, and the proximal tip is connectable to a drill.
 
4. The tool of any of examples 1-3 wherein the proximal section is cylindrical.
 
5. The tool of any of examples 1-4 wherein the proximal section has a proximal width and the distal section has a distal width and the proximal width is equal the distal width.
 
6. The tool of any of examples 1-5 wherein the tool has a tool length and a length of the proximal section is at least 30% of the tool length.
 
7. The tool of any of examples 1, 3-6 wherein the scraping surface comprises an edge formed on the outer surface of the distal end.
 
8. The tool of any of examples 1, 3-7 wherein the scraping surface comprises a plurality of edges formed on the distal section.
 
9. The tool of any of examples 1, 3-8 wherein the portion of the distal section that scrubs the medullary cavity comprises a triangular cross section and three edges.
 
10. The tool of any of examples 1-9 that further includes an intermediary section between the proximal section and the distal section.
 
11. The tool of example 10 wherein the intermediary section has an intermediary width, and the intermediary width is less than a width of the proximal section or less than a width of the distal section.
 
12. The tool of any of examples 10-11 wherein the intermediary section is cylindrical.
 
13. The tool of any of examples 1-12 wherein the distal section includes a distal tip with at least one cutting surface.
 
14. The tool of example 13 wherein the distal tip has three cutting surfaces.
 
15. The tool of any of examples 1-14 that is one piece.
 
16. The tool of any of examples 1-14 wherein the distal section is attachable to the intermediary section.
 
17. The tool of example 15 wherein the distal section has a distal tip and a proximal end, and the proximal end is configured to be received in a distal end of the intermediary section.
 
18. The tool of any of examples 13-17 wherein the distal tip is a structure that narrows in width from a scraping surface to the cutting surface.
 
19. The tool of example 17 wherein the distal tip is triangular and has three proximal surfaces, wherein each proximal surface terminates in a triangular cutting surface.
 
20. A system including the tool of any of examples 1-19 and a driver.
       
 
         [0034]    Having thus described preferred embodiments of the invention, other variations and embodiments that do not depart from the spirit of the invention will become apparent to those skilled in the art. For example, while an exemplary tool has been described above in connection with scrubbing a medullary cavity of a phalange or joint cavity of a digit or appendage, the invention is not so limited. The scope of the present invention is not limited to any particular embodiment, but is instead set forth in the appended claims and the legal equivalents thereof. Further, unless expressly stated in the written description or claims, the steps of any method recited in the claims may be performed in any order capable of yielding the desired result.