Abstract:
An arthroscopic anchor insertion tool and method for inserting consecutive, longitudinally aligned anchors from a common deployment channel of a cannulated needle by employing positive stops to prevent travel of an actuator from simultaneously advancing multiple anchors into a surgical site.

Description:
BACKGROUND 
       [0001]    Fibrous tissue wounds, such as muscle, ligament, and cartilage tears, can be repaired arthroscopically using sutures. Traditionally, to close a fibrous tissue wound, a surgeon would insert two suture needles into the tissue with sutures attached, thread the sutures across the wound, and then tie knots to fix the free ends of the sutures within the tissue. To simplify the wound closure procedure and to improve fixation, various types of suture anchors have been developed. In one example of a suture anchor, one end of a suture is fixed to a resiliently-deformable, bar-shaped suture anchor. The anchor is loaded into the bore of a hollow needle and deployed into or against the fibrous tissue. The surgeon then threads the suture across the wound and tensions a free end of the suture to pull the wound closed. When the surgeon tensions the suture, the anchor becomes oriented transversely to the suture hole, anchoring the suture in place. 
         [0002]    More than one anchor can also be deployed using a single hollow needle, rather than two separate needles. However, an issue arises when the two anchors are placed together inside of a needle. The needle actuator may push both anchors outside of the needle simultaneously, when what is desired is to have the two anchors deploy separately. Conventional approaches require precision when disposing the actuator inside of the needle so as not to prematurely release the second anchor. 
       SUMMARY 
       [0003]    Disclosed herein is an anchor insertion tool and method for inserting consecutive, longitudinally aligned anchors by employing positive stops to prevent travel of an actuator from simultaneously advancing multiple fasteners into a surgical site from a common deployment channel of a cannulated needle. Advantageously, the proposed approach prevents both over-insertion and premature deployment of the anchors. 
         [0004]    In an example, the anchor insertion system includes a needle, the needle having a proximal end, a distal end, and a hollow shaft extending between the proximal and distal ends, the proximal end of the needle having a handle, and the distal end of the needle having a needle tip assembly for housing at least two anchors. The anchor insertion system also includes an actuator assembly for deploying at least one of the at least two anchors from the needle tip assembly, at least a portion of the actuator assembly slidably disposed within the needle. The anchor insertion system also has a cylindrical disk rotatably attached to the actuator assembly, a surface of the cylindrical disk comprising a hole for receiving a guide pin, and a sleeve disposed around the cylindrical disk, a portion of a surface of the sleeve defining an angled slot therethrough. The guide pin is configured to engage the angled slot, and the angled slot defines first and second stops for preventing the actuator assembly from simultaneously deploying the at least two anchors into a surgical site. 
         [0005]    In other examples, the anchor insertion system further includes a deployment knob at least partially in contact with the rotary disk for advancing the actuator assembly. The at least two anchors are longitudinally aligned within a channel of the needle tip assembly. The anchor insertion system further has a spring for joining the handle to the cylindrical disk. Rotation of the handle gives the spring a torsional and/or compressional load sufficient to activate the actuator assembly. The cylindrical disk is configured to rotate both clockwise and counterclockwise 360 degrees. The at least two anchors are in an undeployed position when the guide pin is located at a proximal end of the angled slot. The first stop in the angled slot corresponds to an insertion depth of the actuator assembly for deploying a first one of the at least two anchors, and the second stop in the angled slot corresponds to an insertion depth of the actuator assembly for deploying a second one of the at least two anchors. The second stop is distal to the first stop along the surface of the sleeve. The needle tip assembly has a pointed distal end for piercing tissue. The handle includes a proximal handle portion and a distal handle portion, an outer diameter of the distal handle portion selected to be larger than an outer diameter of the proximal handle portion. An inner diameter of the sleeve is selected to slide over the proximal handle portion. When the sleeve is slid over the proximal handle portion, the sleeve and the proximal handle portion are locked into place. An outer diameter of the sleeve is selected to match the outer diameter of the distal handle portion. 
         [0006]    An example of the method of surgical repair of this disclosure includes inserting a needle into a first location in tissue, the needle having a proximal end, a distal end, and a hollow shaft extending between the proximal and distal ends, the proximal end of the needle comprising a handle, the distal end of the needle having a needle tip assembly for housing at least two anchors; advancing an actuator assembly slidably disposed within the needle to a first position to deploy a first anchor of the at least two anchors out of the needle into the first location; retracting the actuator assembly; removing the needle from the first location in the tissue and inserting the needle into a second location in the tissue; and advancing the actuator assembly to a second position to deploy a second anchor of the at least two anchors out of the needle into the second location in the tissue, the second position being distal to the first position. In further examples, the first position and the second position are defined by a first stop and a second stop, respectively, of an angled slot, the angled slot defined by a surface of a sleeve disposed around the actuator assembly. The actuator assembly is associated with a rotary disk for housing a guide pin, the guide pin configured to contact the angled slot. The method further includes loading the at least two anchors within a channel of the needle tip assembly prior to inserting the needle into the first location in the tissue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The foregoing and other features will be apparent from the following description of particular embodiments disclosed herein, as illustrated in the accompanying drawings. 
           [0008]      FIG. 1A  shows an exploded view of the anchor insertion system of this disclosure; 
           [0009]      FIG. 1B  shows further detail of the needle tip assembly of  FIG. 1A ; 
           [0010]      FIG. 2  shows a perspective view of the system of  FIG. 1A ; 
           [0011]      FIGS. 3A-C  show the guide pin in the system of  FIG. 1A ; 
           [0012]      FIGS. 4A-C  show the spring for biasing an actuator in the system of  FIG. 1A ; and 
           [0013]      FIGS. 5-7  show sectional views illustrating a method of use of the system of  FIG. 1A . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Examples of the anchor insertion system and method of use will now be discussed with reference to the figures. 
         [0015]    In the description that follows, like components have been given the same reference numerals, regardless of whether they are shown in different examples. To illustrate an example(s) of the present invention in a clear and concise manner, the drawings may not necessarily be to scale and certain features may be shown in somewhat schematic form. Features that are described and/or illustrated with respect to one example may be used in the same way or in a similar way in one or more other examples and/or in combination with or instead of the features of the other examples. 
         [0016]    Comprise, include, and/or plural forms of each are open ended and include the listed parts and can include additional parts that are not listed. And/or is open ended and includes one or more of the listed parts and combinations of the listed parts. 
         [0017]    Referring now to  FIG. 1A , the anchor insertion system  100  of this disclosure is shown in an exploded view. The anchor insertion system  100  includes a needle  110  having a proximal end  111  and a distal end  113 , and a hollow shaft  118  extending between the proximal and distal ends  111 ,  113 . A handle  112  is mounted to the proximal end  111  of the hollow shaft  118  and comprises a passageway therethrough (not shown) in communication with the interior of the hollow shaft  118 . The handle  112  further comprises a proximal handle portion  115  and a distal handle portion  117 , an outer diameter of the distal handle portion  117  being larger than an outer diameter of the proximal handle portion  115 . A needle tip assembly  116  is formed at the distal end  113  of the hollow shaft  118 . The hollow shaft  118  and the needle tip assembly  116  are preferably made of metal. 
         [0018]    The anchor insertion system  100  also includes an actuator assembly  122  associated with a rotary disk  126 , which may be in the form of an open cylinder. At least a portion of the actuator assembly  122  may be comprised of a flexible material, such as Nitinol. A surface of the rotary disk  126  comprises a hole for receiving a guide pin  142 , as further described below. An inner diameter of a channel tube  130 , which may be in the form an open sleeve, is selected to slide over the proximal handle portion  115  as well as a portion of the actuator assembly  122 , such that the channel tube  130  is in contact with the guide pin  142  when the anchor insertion system  100  is assembled. The channel tube  130  may be formed from an injection molded thermoplastic or other suitable material. An outer diameter of the channel tube  130  is selected to match the outer diameter of the distal handle portion  117 . A portion of the surface of the channel tube  130  defines an angled slot  150  formed therethrough. A compression spring  140  is configured for joining the rotary disk  126  and the proximal handle portion  115 , as further described below. An inner diameter of a deployment knob  120  having an open distal end is selected to slide over the channel tube  130  as well as the distal handle portion  117 . 
         [0019]    As shown in  FIG. 1B , the needle tip assembly  116  further comprises a pointed, tissue-piercing distal end  144 . The needle tip assembly  116  is configured to house anchors, which may be two anchors  124   a ,  124   b , within a channel  132  in communication with the interior of the hollow shaft  118 . It is contemplated by this disclosure that a flexible element, such as a suture (not shown), may connect the two anchors  124   a ,  124   b . The two anchors  124   a ,  124   b  can be made from rigid, biocompatible materials, such as polyethylene, an acetal, or polypropylene. Alternatively, the two anchors  124   a ,  124   b  can be made from resiliently deformable materials or from bioabsorbable materials. The anchors  124   a ,  124   b  are preferably unitary, injection molded pieces, but can also be manufactured by other methods. A size and shape of the two anchors  124   a ,  124   b  is selected to fit within the channel  132  of the needle tip assembly  116 . A proximal end of anchor  124   b  may have a recess (not shown) configured to accept the distal end of the actuator assembly  122 . At least a portion of the actuator assembly  122  is slidably disposed within the needle  110  such that, once the piercing distal end  144  of the needle  110  pierces tissue, advancement of the actuator assembly  122  drives the anchors  124   a ,  124   b  out of the needle tip assembly  116  into the tissue. Loading of the anchors  124   a ,  124   b  and actuator assembly  122  into the needle  110  can be performed at the time of manufacture (that is, pre-loaded), or immediately prior to surgery. 
         [0020]    In  FIG. 2 , a proximal portion of the anchor insertion system  100  is shown in an assembled state. Here, the proximal handle portion  115  is shown as attached via the compression spring  140  to the rotary disk  126  secured around the actuator assembly  122 . The guide pin  142  extends from the rotary disk  126  through the angled slot  150  ( FIG. 1A ) in the channel tube  130 , as further described below. An inner portion  121  of the deployment knob  120  is configured to be disposed between a proximal portion of the channel tube  130  and a proximal portion of the actuator assembly  122 , such that the inner portion  121  is in contact with the rotary disk  126 . The compression spring  140  forces the rotary disk  126  to press against the inner portion  121  of the deployment knob  120 , allowing the deployment knob  120  to move the actuator assembly  122  forward. 
         [0021]      FIGS. 3A-C  show detailed views of the actuator assembly  122 . As shown in  FIG. 3A , the rotary disk  126  is secured onto the actuator assembly  122 , which may be via an interference fit with disk holder  127 . The rotary disk  126  is allowed to rotate 360 degrees, both clockwise and counterclockwise. An outer surface of the rotary disk  126  includes a threaded hole  128  for receiving a threaded end  143  of the guide pin  142  ( FIG. 3B ). The rotary disk  126  further includes a distal hole  134  to locate and stabilize the compression spring  140 . A first finger  136  at the proximal end of the compression spring  140  slides into the distal hole  134  on the rotatory disk  126  ( FIG. 3C ). 
         [0022]    As shown in  FIG. 4A , a second finger  138  at the distal end of the compression spring  140  slides into a proximal hole  146  on the proximal handle portion  115 . Accordingly, rotating the handle  112  counterclockwise gives the compression spring  140  a torsional load before the proximal handle portion  115  and channel tube  130  enclosing the actuator assembly  122  are locked into place. As shown in  FIGS. 4B and 4C , opposing tabs  147  on the surface of the proximal handle portion  115  are configured to snap into corresponding slots  148  on the surface of the channel tube  130 . The torsional and compressional load of the compression spring  140  is sufficient to activate the actuator assembly  122 . 
         [0023]    In  FIGS. 5-7 , sectional views of the needle tip assembly  116  and the channel guide  130  are shown. In  FIG. 5 , anchors  124   a  and  124   b  reside in consecutive positions in the channel  132  of the needle tip assembly  116 . The guide pin  142  is shown as disposed within the angled slot  150  of the channel tube  130 . The anchors  124   a  and  124   b  are in an undeployed position when the guide pin  142  is located at the proximal end of the angled slot  150 . The angled slot  150  has a pattern that limits forward travel of the actuator assembly  122 , as further described below. 
         [0024]    Now turning to  FIG. 6 , rotation of the rotary disk  126  allows the guide pin  142  to follow the angled slot  150  axially to a 90 degree bend defining a first stop point  152 . The 90 degree bend corresponds to an insertion depth of the actuator assembly  122  for deploying the first anchor  124   a . The guide pin  142  stops the actuator assembly  122  which releases the first anchor  124   a  out of the needle tip assembly  116 . 
         [0025]    In  FIG. 7 , following the deployment of the first anchor  124   a , the torsional force of the compression spring  140  causes rotation of the rotary disk  126  and guide pin  142  to allow slight retraction of the actuator assembly  122 . The guide pin  142  moves slightly backwards from first stop point  152  along the angled slot  150 , then follows the angled slot  150  forward to a portion corresponding to a second stop point  154  distal to the first stop point  152 . This arrangement of stop points  152 ,  154  allows greater forward (insertion) travel for deploying the second anchor  124   b . The guide pin  142  stops the actuator assembly  122  which releases anchor  124   b  out of the needle tip assembly  116 . 
         [0026]    In use, once the anchor insertion assembly  100  is inserted to the surgical site, rotation of the deployment knob  120  achieves the desired articulation angle. Anchors  124   a  and  124   b  have been loaded into the channel  132  in the needle tip assembly  116  prior to surgical insertion of the anchor insertion assembly  100 . A surgeon inserts the needle tip assembly  116  through a first location in tissue to pierce a slit sufficiently large to pass the anchor  124   a . The actuator assembly  122  is slid forward via the deployment knob  120  for disposing the first anchor  124   a  through the slit. The needle is removed from the first location and the procedure is repeated at a second location in the tissue for inserting the second anchor  124   b . Therefore, the anchor insertion assembly  100  advantageously implements a multi-stage insertion depth limitation employing stop points  152 ,  154  at each insertion depth such that the stop points  152 ,  154  prevent travel of the actuator assembly  122  from advancing multiple anchors into the surgical site, as well as over-insertion of the anchors. 
         [0027]    While the system, apparatus and methods defined herein have been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.