Radially compressed dehydrated spinal nucleus implants

Abstract

A radially compressed xerogel spinal nucleus implant is manufactured and utilized for implantation into an intervertebral disc space. The implant has an optimized cross-sectional ellipsoid configuration which facilitates insertion of the implant through a minimal incision in the annulus. Radial compression is achieved by exerting substantially equilateral circumferential compression on an object contained within a radially collapsible member for exerting substantially equilateral circumferential compression on the object. Radial compression may also be achieved by exerting substantially equilateral circumferential compression force on a spinal nucleus implant via gas pressure in a sealed chamber.

1 - 23 . (canceled) 
     
     
         24 . A method of shaping a spinal nucleus implant comprising providing a spinal nucleus implant made, at least in part, of a hydrogel, inserting the implant into a radially collapsible member for exerting substantially equilateral circumferential compression on an object contained within the member, exerting substantially equilateral circumferential compression on the implant, thereby causing the implant to assume a rod-shaped configuration substantially corresponding to the configuration of the radially collapsible member. 
     
     
         25 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the radial aspect of the implant is compressed while the major or axial axis maintains substantially the same length. 
     
     
         26 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the implant is radially compressed and elongated in the axial direction as the radially collapsible member exerts substantially equilateral circumferential compression on the implant. 
     
     
         27 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the hydrogel is initially fully or nearly fully hydrated and, during compression, is made to be at least partially dehydrated. 
     
     
         28 . A method of shaping a spinal nucleus implant according to  claim 27  wherein dehydration is accomplished by compression of the implant. 
     
     
         29 . A method of shaping a spinal nucleus implant according to  claim 27  wherein dehydration is accomplished by regulating at least one condition selected from the group consisting of temperature, humidity and pressure, of the atmosphere surrounding the collapsible member. 
     
     
         30 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is made of a porous elastic material. 
     
     
         31 . A method of shaping a spinal nucleus implant according to  claim 30  wherein the porous elastic material is made from a material selected from the group consisting of an elastic polymer, rubber and neoprene 
     
     
         32 . A method of shaping a spinal nucleus implant according to  claim 30  wherein the porous elastic material is a woven or non-woven mesh. 
     
     
         33 . A method of shaping a spinal nucleus implant according to  claim 30  wherein the porous elastic material is a braid. 
     
     
         34 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is made of a metal having sufficient porosity to allow water to escape from the implant. 
     
     
         35 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is a radially collapsible sleeve and substantially equilateral circumferential compression is exerted by stretching the collapsible sleeve in an axial direction. 
     
     
         36 . A method of shaping a spinal nucleus implant according to  claim 35  wherein stretching the collapsible sleeve is accomplished by pulling the distal ends of the collapsible sleeve away from each other. 
     
     
         37 . A method of shaping a spinal nucleus implant according to  claim 35  wherein stretching the collapsible sleeve is accomplished by fixing one end of the collapsible sleeve may to a stationary anchor while the other end is pulled to stretch the radially collapsible sleeve. 
     
     
         38 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is a cylindrical coil which is made to collapse and exert substantially equilateral circumferential compression on the implant. 
     
     
         39 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is a loop is formed around the circumference of a spinal nucleus implant and pulling the loop tight to exert substantially equilateral circumferential compression on the implant. 
     
     
         40 . A method of shaping a spinal nucleus implant according to  claim 24  wherein the collapsible member is an iris diaphragm mechanism which closes to exert substantially equilateral circumferential compression on the spinal nucleus implant to radially compress the implant. 
     
     
         41 . A method of shaping a spinal nucleus implant comprising providing a spinal nucleus implant made, at least in part, of a hydrogel; placing the spinal nucleus implant within a pressure chamber having at least one sealed channel in communication with the implant, the sealed channel providing for egress of moisture from the implant; exerting pressure by increasing gas pressure in the pressure chamber to cause substantially equilateral circumferential compression of the implant. 
     
     
         42 . A method of shaping a spinal nucleus implant according to  claim 41  wherein the implant elongates axially through the sealed channel. 
     
     
         43 - 52 . (canceled)