Abstract:
The invention includes a tendon stripper comprising: (a) a frame, including a cautery, that is adapted to separate surrounding tissue along a length of a tendon; (b) a handle mounted to the frame that is adapted to reposition the frame with respect to the tendon; and (c) an actuator in communication with the cautery and operative to activate the cautery, where activation of the cautery is adapted to sever the tendon. The invention also includes a method of stripping a tendon comprising: (a) exposing a tendon; (b) aligning a tendon stripper guide with respect to a first location to the tendon; (c) repositioning the tendon stripper guide along the tendon from the first location of the tendon to a second location of the tendon, where the act of repositioning of the tendon stripper guide is operative to separate surrounding tissue from the tendon between the first location and the second location; (d) activating a cautery to sever the tendon approximate the second location; and (e) cutting the tendon at a location other than the second location to provide a tendon segment.

Description:
RELATED ART  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is directed to orthopedic surgical devices and associated methods of Minimally Invasive Surgery (MIS) and, more specifically, to tendon strippers and associated methods of harvesting tendons for use with MIS.  
         [0003]     2. Brief Discussion of Related Art  
         [0004]     The human body can frequently be impaired through dysfunction of an extremity commonly caused by loss of tendon or ligament function. Although repair of the ligament or tendon can be accomplished if the injury is recognized early, delayed treatment of these types of injuries or conditions may require a tendon transfer.  
         [0005]     Tendon transfer utilizes the power and function of a normal tendon by surgically moving the tendon to another area of the body to substitute or supplement the function of an injured or diseased tendon. The surgical procedure involved with tendon transfer includes exposing both the diseased tendon and the normal tendon, as well as re-routing the origin or insertion of both tendons. A large incision is utilized with this technique to facilitate accurate placement of the transferred tendon. The tendon, once exposed, is transected under clear view of the surgeon and thereafter implanted in the desired location. Implantation may include anchoring the tendon to bone to mimic a new function, or include suturing and weaving the harvested tendon to the diseased tendon to supplement its strength.  
         [0006]     The complications associated with conventional tendon transfer include the rather large surgical incision and resulting exposure. Scarring will frequently occur after surgery in a proportionate amount to the size and length of the incision and exposure. This scarring has been known to limit the function of the newly transferred tendon by adhering to the newly transferred tendon to its surrounding structure.  
         [0007]     An exemplary tendon transfer may involve a torn tendon in the foot. The posterior tibial tendon is a critical tendon structure on the medial (inner border) side of the ankle. The ankle and foot will deviate in an outward direction as the posterior tibial posterior tibial tendon fails to function properly, thereby causing a progressive flatfoot deformity. If the posterior tibial tendon is near failure, the appropriate surgical intervention involves harvesting a neighboring tendon (flexor digitorum longus) and transferring the harvested tendon to the navicular bone to reestablish the normal function of the posterior tibial tendon. Harvesting the flexor digitorum longus tendon (as well as any other harvested tendon) generally requires extensive surgical dissection into the depths of the foot. The most common complication associated with this surgery is not the failure of the transferred tendon, but rather the pain and swelling associated with surgery around the critical veins and nerves in the foot. Thus, there is a need in the relevant art for surgical equipment and associated techniques for reducing the complications associated with tendon harvesting.  
       SUMMARY  
       [0008]     The present invention is directed to orthopedic surgical devices and associated methods of Minimally Invasive Surgery (MIS) and, more specifically, to tendon strippers and associated methods of harvesting tendons for use with MIS.  
         [0009]     It is a first aspect of the present invention to provide a tendon stripper comprising: (a) a frame, including a cautery, that is adapted to separate surrounding tissue along a length of a tendon; (b) a handle mounted to the frame that is adapted to reposition the frame with respect to the tendon; and (c) an actuator in communication with the cautery and operative to activate the cautery, where activation of the cautery is adapted to sever the tendon.  
         [0010]     In a more detailed embodiment of the first aspect, the frame includes a distal guide adapted to at least partially circumscribe at least a portion of the tendon, where the distal guide is adapted to guide the frame along the length of the tendon. In yet another more detailed embodiment, the cautery includes an electrical cautery wire, the frame includes a housing along which the electrical cautery wire extends, the electrical cautery wire is longitudinally repositionable along a length of the housing, and the electrical cautery wire is mounted to the distal guide to at least partially circumscribe a portion of the tendon in a pre-severance position. In a further detailed embodiment, the electrical cautery wire is mounted to the actuator, and the actuator is operative to reposition the electrical cautery wire between the pre-severance position and a post-severance position, where the repositioning of the electrical cautery wire between the positions includes repositioning the electrical cautery wire along the length of the housing. In still a further detailed embodiment, the distal guide is arcuately shaped, and a distal end of the distal guide is tapered. In a more detailed embodiment, the distal guide includes a cylindrical portion, an aspect of the cylindrical portion is repositionable between an open position and a closed position, where the cylindrical portion circumscribes the tendon in the closed position and the cylindrical portion includes a latch operative to maintain the cylindrical portion in the closed position when engaged and is operative to allow the cylindrical portion to be positioned in the open position when disengaged.  
         [0011]     In yet another more detailed embodiment of the first aspect, the electrical cautery wire is mounted to the cylindrical portion, the electrical cautery wire at least partially circumferentially lines a portion of an interior wall of the cylindrical portion in a U-shaped pre-severance position, and the electrical cautery wire is displaced from the U-shaped pre-severance position to a more taught post-severance position in order to sever the tendon. In still another more detailed embodiment, the handle includes a cavity adapted to house a portable power source, and the handle includes electrical leads adapted to be in electrical communication with the portable power source and the cautery. In a further detailed embodiment, the actuator is repositionably mounted to the handle, the cautery includes an electrical cautery wire, and the actuator is mounted to the electrical cautery wire so that movement of the actuator from a first position to a second position is operative to reposition the electrical cautery wire from a pre-severance position with respect to the tendon to a post-severance position with respect to the tendon.  
         [0012]     It is a second aspect of the present invention to provide a method of stripping a tendon comprising: (a) exposing a tendon; (b) aligning a tendon stripper guide with respect to a first location to the tendon; (c) repositioning the tendon stripper guide along the tendon from the first location of the tendon to a second location of the tendon, where the act of repositioning of the tendon stripper guide is operative to separate surrounding tissue from the tendon between the first location and the second location; (d) activating a cautery to sever the tendon approximate the second location; and (e) cutting the tendon at a location other than the second location to provide a tendon segment.  
         [0013]     In a more detailed embodiment of the second aspect, the act of aligning the tendon stripper guide includes opening the tendon stripper guide to allow insertion of the tendon and thereafter closing the tendon stripper guide to circumscribe the tendon to inhibit egress of the tendon in a radial direction. In yet another more detailed embodiment, the act of aligning the tendon stripper guide includes aligning the tendon stripper guide with respect to a tendon connected to bodily tissue at each end. In a further detailed embodiment, the act of aligning the tendon stripper guide includes providing a direct line of sight to the first location, and the act of repositioning the tendon stripper guide along the tendon includes discontinuing the direct line of sight prior to reaching the second location. In still a further detailed embodiment, the act of aligning the tendon stripper guide includes providing a direct line of sight to the first location, and the act of repositioning the tendon stripper guide along the tendon includes discontinuing the direct line of sight prior to reaching the second location. In a more detailed embodiment, the act of activating the cautery includes repositioning an actuator to provide electrical communication with a power source to energize the cautery.  
         [0014]     In yet another more detailed embodiment of the second aspect, the cautery includes an electrical wire cautery, the electrical wire cautery is operatively coupled to the actuator, and the act of repositioning the actuator is operative to reposition the electrical wire cautery from a pre-severance position to a post-severance position. In still another more detailed embodiment, the cautery is mounted to an interior surface of the tendon stripper guide that at least partially circumscribes the tendon, and the tendon stripper guide is operative to inhibit destruction of the surrounding tissue when the cautery is activated.  
         [0015]     It is a third aspect of the present invention to provide a method of stripping a tendon comprising: (a) exposing a tendon; (b) aligning a tendon stripper guide with respect to a first location to the tendon; (c) repositioning the tendon stripper guide along the tendon from the first location of the tendon to a second location of the tendon, where the act of repositioning of the tendon stripper guide is operative to separate surrounding tissue from the tendon between the first location and the second location; (d) tensioning a cutting wire to sever the tendon approximate the second location; and (e) cutting the tendon at a location other than the second location to provide a tendon segment.  
         [0016]     The aforementioned aspects should not be considered a completely inclusive summary of the present invention. Reference is had to the Detailed Description for a more accurate and inclusive understanding of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is an overhead view of a first exemplary embodiment of the present invention;  
         [0018]      FIG. 2  is a left side perspective view of the first exemplary embodiment of  FIG. 1 , shown with a cut-away view of the exemplary handle;  
         [0019]      FIG. 3  is a frontal elevated perspective view of the first exemplary embodiment of  FIG. 1 ;  
         [0020]      FIG. 4  is an elevated perspective view of the exemplary barrel of the first exemplary embodiment of  FIG. 1 , shown in the open position;  
         [0021]      FIG. 5  is a cross-sectional view of the exemplary barrel of  FIG. 4  in the closed position, where the cautery wire is shown in the pre-severance position; and  
         [0022]      FIG. 6  is a cross-sectional view of the exemplary barrel of  FIG. 4  in the closed position, where the cautery wire is shown in the post-severance position. 
     
    
     DETAILED DESCRIPTION  
       [0023]     The exemplary embodiments of the present invention are described and illustrated below to encompass orthopedic surgical devices and associated techniques that are applicable in areas such as, without limitation, tendon harvesting and Minimally Invasive Surgery (MIS). Of course, it will be apparent to those of ordinary skill in the art that the preferred embodiments discussed below are exemplary in nature and may be reconfigured without departing from the scope and spirit of the present invention. However, for clarity and precision, the exemplary embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present invention.  
         [0024]     Referencing  FIGS. 1-3 , a first exemplary tendon stripper  10  includes a handle  12  mounted to a semiflexible plastic connecting rod  14  at a proximal end  16 . The connecting rod  14  extends outward from the handle  12  and is mounted to a plastic barrel  18  at a distal end  20 . The handle  12  includes a cavity  22  adapted to house a portable power source  24  such as, without limitation, batteries. Electrical leads  26  housed within the cavity  22  provide electrical communication between one of a set of contact plates (not shown) and the batteries  24 , while a second contact plate is in electrical communication with an electrically powered cautery  28 . For purposes of explanation only, the electrically powered cautery  28  of the first exemplary embodiment is described as an electrical monofilament wire cautery. Those of ordinary skill will readily understand that other cautery devices may be used in lieu of or in addition to the electrical monofilament wire cautery  28  such as, without limitation, monopolar/bipolar cautery, radiofrequency probe, optical filament, or laser energy.  
         [0025]     In exemplary form, the handle  12  of the stripper  10  is intended to be seated within the palm of the user&#39;s hand, with the user&#39;s finger wrapping around the handle  12  and the user&#39;s thumb facing the barrel  18 . An actuator  30  repositionably mounted to the handle  12  is intended to be engaged by a user&#39;s thumb in order to reposition the actuator and activate the electrical wire cautery  28 . The actuator  30  rides within a channel  32  formed within the surface of the handle  12  that provides linear travel forward and backward (as shown by the arrow of  FIG. 2 ). A forward depression  34  within the actuator  30  includes a plurality of horizontal plateaus  36  that are adapted provide a gripping surface for user&#39;s thumb to engage while moving the actuator backward. In addition, the actuator  30  includes a second, reward depression  38  adapted to receive a user&#39;s thumb when moving the actuator  30  forward.  
         [0026]     The underside of the actuator  30  includes a corresponding set of contact plates (not shown) that provide electrical communication between the batteries  24  and the electrical wire cautery  28  after the actuator is moved rearward beyond a predetermined point. Those of ordinary skill will realize that the precise point at which the contact plates close the circuit to provide electric current to the cautery  28  is within the purview of one of ordinary skill and may be changed without departing from the scope and spirit of the present invention. Likewise, it is within the scope of the invention to provide a separate actuator (other than the actuator  30  mounted to the electrical wire cautery  28 ) that is responsible for establishing electrical communication between the cautery  28  and batteries  24 .  
         [0027]     A frontal aspect  40  of the actuator  30  is coupled to the electrical wire cautery  28 , which extends through a cylindrical conduit  42  extending substantially the entire length of the connecting rod  14 . The electrical wire cautery  28  exits the distal end of the connecting rod  14  through a hole  44  connecting the interior of the conduit  42  with the interior of the barrel  18 .  
         [0028]     Referring to  FIG. 4 , the barrel  18  includes a first semiannular section  46  that is repositionable with respect to a second semiannular section  48  by way of a hinge  50  and catch  52 . The hinge  50  may be a living hinge or mechanical hinge operative to allow an opening  54  between the sections  46 ,  48  to accommodate a linear section of a tendon to be lowered into the interior of the barrel  18 . It is to be understood that the hinged barrel  18  of the first exemplary tendon stripper  10  accommodates tendons that are either detached from bodily tissue at one or both ends, as well as tendons attached to bodily tissue at opposing ends. Exemplary manually operative catches or fasteners  52  may be snap-fit or any other type of catch/fastener that provides for selective opening and closing of the sections  46 ,  48 . It is also within the scope of the invention that the catch be automatically operated. In the closed position, the sections  46 ,  48  provide a cylindrical barrel  18  that includes a circular cross-section. Nevertheless, it is to be understood that the dimensions and contours of the barrel  18  are exemplary in nature and may be reconfigured to include, without limitation, rectangular cross-sections and oblong circular cross-sections. As will be discussed in more detail below, the distal end  20  of each of the sections  46 ,  48  and the distal end  20  of the connecting rod  14  are beveled to decrease the resistance to longitudinal movement of the barrel  18  in the proximal direction to strip the tissue surrounding the tendon as the barrel  18  progresses along the length of the tendon.  
         [0029]     Referring to  FIGS. 4-6 , the electrical wire cautery  28  is anchored within a cavern  58  of the first semiannular section  46 . The electrical wire cautery  28  extending beyond the cavern  58  is seated within a circumferential recess  60  of the interior of the barrel  18  (formed by the two semiannular interior surfaces of the sections  46 ,  48 ) to circumferentially line the interior until reaching the hole  44  leading out of the barrel  18  in the “slacked position.” This slacked position (see  FIGS. 3 and 4 ) corresponds with the position of the actuator  30  in the most forward position or in pre-severance position where the electrical wire cautery  28  accommodates the shape of the tendon. In contrast, when the actuator  30  is repositioned rearward (see  FIG. 2 ), the length of the electrical wire cautery  28  within the barrel  18  is substantially decreased resulting in a “taught position” or post-severance position (see  FIG. 6 ). A return wire  62 , in electrical communication with anchored aspect of the wire cautery  28 , runs parallel to the cautery wire in a separate recess  64  within the interior of the barrel  18 . The return wire  62  exits the barrel  18  through the hole  44  and extends through the cylindrical conduit  42  of the connecting rod  14  until reaching the interior of the handle and into electrical communication with one of the electrical contact plates. As discussed above, when the actuator  30  is repositioned rearward to an extent to allow for contact between the electrical contact plates, the electrical circuit is closed and the electrical wire cautery  28  is energized resulting in the wire becoming heated to a sufficient degree to burn through the tendon within the barrel  18 .  
         [0030]     The stripper  10  is manufactured in variable sizes to precisely allow various diameters and lengths of tendons to be harvested. By matching the diameter of the barrel  18  to the prospective tendon to be harvested, the surrounding soft tissue is protected from inadvertent entry. Exemplary measurements for components of the tendon stripper  10  include an overall length of 40 cm. The handle  12  includes a length of 15 cm and a diameter of 2 mm diameter. The handle  12  may be fabricated from plastic. The electrical wire cautery  28  is commercially available from Malin Company, Inc., 5400 Smith Road, Cleveland, Ohio 44142 and may be tailored to match the preferred length of the rod  14  and circumference of the barrel  18 . The connecting rod  14  is flexible and commercially available from The MedTech Group, Inc., 6 Century Road, South Plainfield, N.J. 07080. The barrel  18  is fabricated from a surgically acceptable plastic and includes a length of approximately 1.5 cm and a diameter ranging between approximately 4.0 mm. to about 9.0 mm.  
         [0031]     The electrical wire cautery  28  of the present invention may comprise at least two aspects. A first aspect of the wire cautery  28 , positioned within the barrel  18  as shown in  FIGS. 4 and 5 , may be comprised of a high resistance filament, whereas a second aspect comprising the remainder of the wire cautery  28  may be comprised of a low resistance wire. The lengths of the first and second aspects of the electrical wire cautery  28  are well within the purview of one of ordinary skill.  
         [0032]     The exemplary tendon stripper  10  may be utilized for accurate and atraumatic harvesting of a tendon failing to include a detached free end. A small 3 cm incision is made to expose a subcutaneous portion of a tendon. The catch  52  is released to allow the semiannular sections  46 ,  48  of the barrel  18  to be separated via movement of the hinge  50  to create the opening  54  through which the viewed tendon is longitudinally repositioned to pass through and lie on the interior of the barrel  18 . After the tendon is located in the interior of the barrel  18 , the sections  46 ,  48  are brought together to close the opening  54  and the catch  52  is secured.  
         [0033]     The barrel  18  is advanced within the tissue plane of the tendon until reaching a predetermined location, while concurrently avoiding exposure of companion neurovascular structures. Movement of the barrel  18  along the tendon is operative to separate the tendon from surrounding bodily tissue. Once the barrel  18  is advanced to a predetermined location along of the tendon, the actuator  30  is repositioned rearward away from the barrel  18  to provide contact between the metal plates to close the circuit and energize the electrical wire cautery  28  positioned underneath of the tendon. As actuator  30  is moved further away from the barrel  18 , portions of the electrical wire cautery  28  are drawn out of the barrel  18  through the hole  44 , thereby reducing the length of the electrical wire cautery  28  remaining within the barrel  18 . The tendon in the path of the moving electrical wire cautery  28 , while energized, is cauterized. Eventually, enough of the electrical wire cautery  28  is withdrawn from the barrel  18  to arrive at the taught position shown in  FIG. 6 . At this point, any tendon within the barrel  18  is completely severed by the action of the electrical wire cautery  28 . The tendon is pulled away from the barrel  18  and delivered to the incision. The actuator  22  is pushed to an off position and the stripper  10  is withdrawn.  
         [0034]     The exemplary stripper  10  is advantageous in both arthroscopy and MIS applications to minimally disrupt surround soft tissue structures. The body responds to less injury and heals faster as the incision and wound is smaller by using a stripper  10  that does not require line of sight prior to cauterizing the tendon, nor requires that one end of the tendon be free prior to cauterization. Moreover, the surrounding tissue is protected from the heat of the cauterization by the barrel  18  of the tendon stripper  10 .  
         [0035]     It is also within the scope of the present invention to exchange the cautery  28  for a razor wire. In this manner, the actuator might be rearwardly repositioned to withdraw a portion of the razor wire from the barrel in a manner that would be operative to sever the tendon. It is also within the scope of the invention to provide a delivery system for optical cable to deliver laser energy or to use the barrel to deliver a probe for radiofrequency energy or monopolar/bipolar electrocautery.  
         [0036]     Following from the above description and invention summaries, it should be apparent to those of ordinary skill in the art that, while the methods and apparatuses herein described constitute exemplary embodiments of the present invention, the invention contained herein is not limited to this precise embodiment and that changes may be made to such embodiments without departing from the scope of the invention as defined by the claims. Additionally, it is to be understood that the invention is defined by the claims and it is not intended that any limitations or elements describing the exemplary embodiments set forth herein are to be incorporated into the interpretation of any claim element unless such limitation or element is explicitly stated. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclosed herein in order to fall within the scope of any claims, since the invention is defined by the claims and since inherent and/or unforeseen advantages of the present invention may exist even though they may not have been explicitly discussed herein.