Methods and apparatus for treating disc herniation and preventing the extrusion of interbody bone graft

Abstract

Methods and apparatus for treating disc herniation provide a conformable device which assumes a first shape associated with insertion and a second shape or expanded shape to occlude the defect which typically follows partial discectomy. The device may take different forms according to the invention, including patches size to cover the defect or plugs adapted to fill the defect. In a preferred embodiment, however, the device is a gel or other liquid or semi-liquid which solidifies to occlude the defect from within the body of the disc itself. In another preferred embodiment, a mesh screen is collapsed into an elongated form for the purposes of insertion, thereby minimizing the size of the requisite incision while avoiding delicate surrounding nerves. Such a configuration also permits the use of instrumentation to install the device, including, for example, a hollow tube or sheath adapted to hold the collapsed screen, and a push rod to expel the collapsed device out of the sheath for use in occluding the disc defect. A device according to the invention may further include one or more anchors to assist in permanently affixing the device with respect to the defect.

1 . A method for treating an annulus fibrosis having an outer layer, at least one inner layer, and a defect extending through the outer and inner layers, comprising the steps of: 
 inserting an implant into the defect in the annulus fibrosis;    advancing the implant distally beyond the outer layer in the annulus fibrosis; and    expanding the implant to a diameter larger than the defect,    wherein the expanded implant has a convex surface and wherein the convex surface is facing outwardly with respect to the outer layer of the annulus fibrosis, and wherein the implant prevents escape of nucleus pulposus through the defect.    
     
     
         2 . The method of  claim 1 , wherein the step of inserting the implant into the defect further comprises the steps of inserting an elongate tubular sheath into the defect and advancing the implant through the sheath into and distally beyond the outer layer in the annulus fibrosis.  
     
     
         3 . The method of  claim 1 , wherein the step of advancing the implant through the sheath further comprises the step of operating a plunger to push the implant out of the sheath.  
     
     
         4 . The method of  claim 1 , wherein the implant is a porous mesh.  
     
     
         5 . The method of  claim 1 , wherein the implant is a self expanding mesh  
     
     
         6 . The method of  claim 5 , wherein the mesh has a first elongated shape and a memory of a second radially expanded shape, and wherein the method further comprises the step of straightening the mesh for introduction into the defect, whereupon it is released and assumes the second radially expanded shape due to the memory effect.  
     
     
         7 . The method of  claim 1 , wherein the implant further comprises a radio-opaque contrast material.  
     
     
         8 . The method of  claim 1 , wherein the implant further comprises one or more anchors, and wherein the method further comprises the step of securing the one or more anchors to at least one of the annulus fibrosis and the vertebra.  
     
     
         9 . The method of  claim 1 , wherein the implant is advanced distally so that the proximal end of the implant lies beyond the outer layer of the annulus fibrosis.  
     
     
         10 . The method of  claim 1 , wherein the implant is arranged in a generally conical shape when expanded.  
     
     
         11 . The method of  claim 1 , wherein the implant is titanium.  
     
     
         12 . The method of  claim 1 , wherein the implant is expanded within the defect proximal to the nucleus pulposus.  
     
     
         13 . A method for treating an annulus fibrosis having an outer layer, at least one inner layer, and a defect extending through the outer and inner layers, comprising the steps of: 
 inserting an implant into the defect in the annulus fibrosis;    advancing the implant distally beyond the outer layer in the annulus fibrosis; and    expanding the implant to a diameter larger than the defect,    wherein the expanded implant has a convex surface and wherein the convex surface is facing inwardly with respect to the outer layer of the annulus fibrosis, and wherein the implant prevents escape of nucleus pulposus through the defect.    
     
     
         14 . The method of  claim 13 , wherein the step of inserting the implant into the defect further comprises the steps of inserting an elongate tubular sheath into the defect and advancing the implant through the sheath into and distally beyond the outer layer in the annulus fibrosis.  
     
     
         15 . The method of  claim 13 , wherein the step of advancing the implant through the sheath further comprises the step of operating a plunger to push the implant out of the sheath.  
     
     
         16 . The method of  claim 13 , wherein the implant is a porous mesh.  
     
     
         17 . The method of  claim 13 , wherein the implant is a self expanding mesh  
     
     
         18 . The method of  claim 17 , wherein the mesh has a first elongated shape and a memory of a second radially expanded shape, and wherein the method further comprises the step of straightening the mesh for introduction into the defect, whereupon it is released and assumes the second radially expanded shape due to the memory effect.  
     
     
         19 . The method of  claim 13 , wherein the implant further comprises a radio-opaque contrast material.  
     
     
         20 . The method of  claim 13 , wherein the implant further comprises one or more anchors, and wherein the method further comprises the step of securing the one or more anchors to at least one of the annulus fibrosis and the vertebra.  
     
     
         21 . The method of  claim 13 , wherein the implant is advanced distally so that the proximal end of the implant lies beyond the outer layer of the annulus fibrosis.  
     
     
         22 . The method of  claim 13 , wherein the implant is arranged in a generally conical shape when expanded.  
     
     
         23 . The method of  claim 13 , wherein the implant is titanium.  
     
     
         24 . The method of  claim 13 , wherein the implant is expanded within the defect proximal to the nucleus pulposus.