Flexible elongated chain implant and method of supporting body tissue with same

Abstract

Implants and methods for augmentation, preferably by minimally invasive procedures and means, of body tissue, including in some embodiments repositioning of body tissue, for example, bone and, preferably vertebrae are described. The implant may comprise one or more chain linked bodies inserted into the interior of body tissue. As linked bodies are inserted into body tissue, they may fill a central portion thereof and for example in bone can push against the inner sides of the cortical exterior surface layer, for example the end plates of a vertebral body, thereby providing structural support and tending to restore the body tissue to its original or desired treatment height. A bone cement or other filler can be added to further augment and stabilize the body tissue. The preferred implant comprises a single flexible monolithic chain formed of allograft cortical bone having a plurality of substantially non-flexible bodies connected by substantially flexible links.

1 . An apparatus for augmentation of body tissue comprising: 
 a flexible elongated member having a longitudinal length substantially larger than its height or its width, wherein the member comprises:    a plurality of substantially non-flexible bodies; and    a plurality of substantially flexible links interconnecting the bodies, the bodies and links connected end-to-end to form the elongated member,    wherein the elongated member is formed of a biocompatible material.    
     
     
         2 . The apparatus of  claim 1  wherein the elongated member is formed as an integral monolithic chain.  
     
     
         3 . The apparatus of  claim 2  wherein the monolithic chain is formed of bone.  
     
     
         4 . The apparatus of  claim 3 , wherein the monolithic chain is formed of allograft bone.  
     
     
         5 . The apparatus of  claim 4  wherein the flexible links are formed of bone that has been demineralized to a greater extent than the bodies.  
     
     
         6 . The apparatus of  claim 5  further comprising a coating applied to at least a portion of the elongated member.  
     
     
         7 . The apparatus of  claim 6  wherein the coating comprises at least one of the group selected from a therapeutic agent, a bone cement, an antibiotic, and a bone growth stimulating substance.  
     
     
         8 . The apparatus of  claim 7  wherein the coating comprising a bone cement that may be activated upon insertion into the body tissue.  
     
     
         9 . The apparatus of  claim 4  wherein at least a portion of the bodies comprise an outer surface configured to promote bone in-growth.  
     
     
         10 . The apparatus of  claim 1 , wherein the bodies are larger in size than the links, and chain is bendable such that adjacent bodies can touch without breaking or cracking the chain.  
     
     
         11 . The implant of  claim 1  insertable into bone.  
     
     
         12 . The implant of  claim 1  insertable between two vertebrae.  
     
     
         13 . An apparatus for augmenting a body tissue comprising an elongated member having a longitudinal length greater than either its height or width, the elongated member formed of allograft bone and comprising: 
 a plurality of bodies and    a plurality of links interconnecting the bodies wherein the links are more flexible and have a greater degree of demineralization than the bodies.    
     
     
         14 . The apparatus of  claim 13  wherein the bodies have a first cross-sectional size and the links have a second cross-sectional size, the first cross-sectional size being larger than the second cross-sectional size.  
     
     
         15 . The apparatus of  claim 13  wherein the elongated member has a length between about 40 mm and about 150 mm, a maximum height between about 2 mm and about 8 mm, and a maximum width of between about 3 mm and about 8 mm.  
     
     
         16 . The apparatus of  claim 13  further comprising a bone cement coating covering at least a portion of the elongated member wherein the coating has an active state and inactive state, the bone cement being user controlled to change from the inactive state to the active state, the active state permitting the cement to attach to another surface.  
     
     
         17 . A method of treating osteoporotic bone comprising: 
 providing a monolithic, flexible, elongated member having a longitudinal length greater than either its height or its width, the elongated member formed of allograft bone comprising a plurality of bodies connected together by a plurality of links wherein the links are located between the bodies and the links have a greater degree of demineralization and flexibility than the bodies,    inserting the elongated member into the interior of the bone.    
     
     
         18 . The method of  claim 17  wherein the elongated member is inserted along its longitudinal length.  
     
     
         19 . The method of  claim 17  wherein the elongated member is inserted simultaneously with bone cement that will cure to a hardened state in situ in the interior of the bone.  
     
     
         20 . The method of  claim 19  wherein at least a portion of the elongated member extends from the bone.  
     
     
         21 . The method of  claim 17  wherein the elongated member is inserted through a cannula into the interior of a vertebrae.  
     
     
         22 . The method of  claim 17  wherein the elongated member is inserted with sufficient force to move at least a portion of the cortical exterior surface of the bone.  
     
     
         23 . The method of  claim 17  further comprising: 
 creating an opening in the cortical exterior surface of a bone; and    creating a cavity within the interior of the bone.    
     
     
         24 . The method of  claim 23  wherein the step of creating the cavity comprises compacting bone cells within the bone.  
     
     
         25 . The method of  claim 17  further comprising inserting at least one selected from the group of bone chips, therapeutic agents, bone-stimulating agents and antibiotics into the interior of the bone.  
     
     
         26 . The method of  claim 17  further comprising: 
 creating an opening in the exterior surface of the bone;    creating a passageway from the opening to the interior of the bone; and    filling at least one of the opening and the passageway with a plug of bone cement to prevent the escape of the elongated member from the interior of the bone.    
     
     
         27 . The method of  claim 17  wherein the step of inserting the elongated member comprises bending the plurality of links so that the bodies within the interior of the bone contact each other.  
     
     
         28 . The method of  claim 27  wherein the bodies are larger in size than the links.  
     
     
         29 . The method of  claim 28  wherein after the step of inserting the elongated member into the interior of the bone, the method further comprises inserting at least one selected from the group of bone cement, and bone chips.  
     
     
         30 . A method of treating the spine comprising: 
 providing a flexible elongated member having a longitudinal length greater than its height or width, the elongated member formed of allograft bone comprising a plurality of bodies connected together by a plurality of links wherein the links are located between the bodies and the links have a greater degrees of demineralization and flexibility than the bodies; and    inserting the elongated member between two adjacent vertebrae.    
     
     
         31 . The method of  claim 30  further comprising inserting the elongated member into the annulus of a spinal disc.  
     
     
         32 . The method of  claim 30  wherein the bodies are larger than the links.  
     
     
         33 . The method of  claim 30  wherein at least one elongated member is formed from a single allograft bone as an integral monolithic structure.  
     
     
         34 . A method of manufacturing an allograft bone implant comprising: 
 machining from bone an elongated member having a longitudinal length greater than either its height or width, the elongated member having a plurality of bodies connected together by a plurality of links wherein the links are located between the bodies and the bodies are connected along a line in end-to-end fashion.    
     
     
         35 . The method according to  claim 34  wherein the bodies have a larger volume than the links and the elongated member is formed from the same bone as one single monolithic implant.  
     
     
         36 . The method of  claim 35  wherein the step of demineralizing the elongated member comprising exposing a plurality of the bodies and a plurality of the links to the same demineralizing solution for substantially the same amount of time.  
     
     
         37 . The method of  claim 36  wherein the links are fully demineralized.  
     
     
         38 . The method of  claim 34  further comprising: 
 covering the plurality of bodies to prevent the bodies from being subject to demineralizing solution, and    exposing the links and covered bodies to demineralizing solution.