Posterior Intervertebral Disc Inserter and Expansion Techniques

Abstract

Insertion and expansion devices for use in inserting motion discs, and associated methods of use.

1 . A method of inserting a curvilinear motion disc having a first and second legs connected by a pivot, each leg having an endportion, the method comprising the steps of:
 a) providing the motion disc in a collapsed position,   b) providing a motion disc inserter comprising a handle having a longitudinal axis and a first end having a first holder and a deployer, the deployer being axially moveable along the axis of the handle,   c) attaching the first endportion of the motion disc to the first holder,   d) contacting the second endportion of the motion disc to the deployer,   e) arcuately inserting the motion disc into the disc space in the collapsed condition, and   f) axially moving the deployer to move the second leg and to expand the motion disc into an open condition.   
     
     
         2 . The method of  claim 1  wherein the handle comprises a rod within a tube, wherein the deployer is attached to a distal end of the rod, and wherein the axial movement of the deployer is accomplished by axially moving the rod within the tube. 
     
     
         3 . The method of  claim 2  wherein the axial movement of the deployer is accomplished by slidably moving the rod within the tube. 
     
     
         4 . The method of  claim 2  wherein the axial movement of the deployer is accomplished by threadably moving the rod within the tube. 
     
     
         5 . The method of  claim 2  wherein the axial movement of the deployer is accomplished by ratcheting movement of a notched rod within the tube. 
     
     
         6 . The method of  claim 1  further comprising monitoring a depth to which the deployer is axially moved by visualizing depth markings. 
     
     
         7 . The method of  claim 6  wherein the depth markings are located on the deployer. 
     
     
         8 . The method of  claim 6  wherein the depth markings are placed on the handle of the inserter. 
     
     
         9 . The method of  claim 1  further comprising the step of distracting the disc space with a distractor prior to inserting the motion disc. 
     
     
         10 . The method of  claim 9  wherein the distractor has a transverse cross-section having a height and a width, wherein the width is greater than the height. 
     
     
         11 . The method of  claim 1  wherein the motion disc is inserted into the disc space from a posterior approach. 
     
     
         12 . The method of  claim 1  further comprising the step of docking the inserter onto a landmark. 
     
     
         13 . The method of  claim 1  wherein the motion disc has a shape selected from the group consisting of a “T” shape, “Y” shape and a “H”-shape. 
     
     
         14 . The method of  claim 1  wherein the motion disc has an “H” shape. 
     
     
         15 . An assembly for inserting a motion disc into a disc space, the assembly comprising:
 a) a curvilinear motion disc having first and second pivoting legs, each leg having an endportion, wherein the first and second leg endportions are in a first collapsed position, and wherein the first and second leg endportions are in a second expanded position, and   b) an inserter comprising a handle having a longitudinal axis and a first end having a first holder and a deployer, the deployer being axially moveable along the axis of the rod,   wherein the first endportion of the motion disc is attached to the first holder, and wherein the second endportion of the motion disc is attached to the deployer.   
     
     
         16 . The assembly of  claim 15  wherein the handle comprises a rod within a tube, and wherein the deployer extends from a distal end of the rod. 
     
     
         17 . The assembly of  claim 16  wherein the rod is slidably movable within the tube. 
     
     
         18 . The assembly of  claim 16  wherein the rod is threadably movable within the tube. 
     
     
         19 . The assembly of  claim 16  wherein the rod is ratchetably movable within the tube. 
     
     
         20 . The assembly of  claim 15  wherein the handle further comprises depth markings. 
     
     
         21 . The assembly of  claim 20  wherein the handle comprises a rod within a tube, and wherein the depth markings are placed on the rod. 
     
     
         22 . The assembly of  claim 20  wherein the depth markings are placed on the inserter handle. 
     
     
         23 . The assembly of  claim 15  further comprising docking means on the inserter. 
     
     
         24 . The assembly of  claim 15  wherein the motion disc has a shape selected from the group consisting of a “T” shape, “Y” shape and a “H” shape. 
     
     
         25 . The assembly of  claim 15  wherein the motion disc has an “H” shape. 
     
     
         26 . A method of inserting a curvilinear motion disc having first and second endportions, the method comprising the steps of:
 a) providing the motion disc in a collapsed position wherein the first and second endportions are close together,   b) inserting into a disc space a distal portion of a motion disc inserter comprising a proximal portion and a curved distal portion comprising upper and lower rails,   c) advancing the motion disc in the collapsed condition through the motion disc inserter to insert the motion disc into the disc space and rotate the motion disc,   f) expanding the motion disc into an open condition in the disc space.   
     
     
         27 . The method of  claim 26  wherein advancing the motion disc is performed with a pusher that holds and pushes a proximal end of the motion disc to advance it distally within the inserter. 
     
     
         28 . The method of  claim 26  wherein advancing the motion disc is performed with a puller comprising a cable wrapped around a pulley located at a distal tip of the track, wherein a first free end of the cable is connected to the motion disc and a second free end of the cable extends out of the proximal tubular portion of the inserter, whereby providing a tensile force on the cable moves the motion disc distally within the inserter and into the disc space. 
     
     
         29 . The method of  claim 26  wherein advancing the motion disc is performed by temporarily attaching interconnecting features that connect the inserter to the implant, and withdrawing the inserter from the disc space, thereby changing a footprint of the motion disc via inserter extraction forces. 
     
     
         30 . The method of  claim 26  wherein advancing the motion disc is performed by placing an instrument having a puller mechanism on a contra-lateral side of the disc space, activating the puller mechanism and thereby pulling the motion disc into position.