Rod-cord dynamic connection assemblies with slidable bone anchor attachment members along the cord

Abstract

A dynamic fixation medical implant having at least two bone anchors includes a longitudinal connecting member assembly having a core portion made from at least one pre-tensioned flexible member and a cooperating pre-compressed surrounding outer sleeve. The sleeve surrounds the core and is disposed between cooperating rigid end members that are attached to the bone anchors.

What is claimed and desired to be secured by Letters Patent is as follows: 
     
         1 . In a medical implant assembly having at least first and second bone anchors cooperating with a longitudinal connecting member, the improvement wherein the connecting member comprises:
 a) a first substantially solid connecting member portion for attachment to the first bone anchor, the first connecting member having at least a pair of spaced apertures;   b) a second connecting member portion for attachment to the second bone anchor; and   c) a transition portion disposed between the first and second connecting member portions, the transition portion having at least one flexible tie looped through the pair of spaced apertures of the first connecting member portion.   
     
     
         2 . The improvement of  claim 1  wherein the first connecting member portion is substantially rigid. 
     
     
         3 . The improvement of  claim 1  wherein the second connecting member portion is substantially rigid. 
     
     
         4 . The improvement of  claim 1  wherein the first connecting member portion has a plurality of apertures and the at least one tie is a plurality of closed loops. 
     
     
         5 . The improvement of  claim 1  wherein the second connecting member portion has a through bore and the at least one tie is received through the through bore. 
     
     
         6 . The improvement of  claim 1  wherein the transition portion further comprises an elastic outer spacer. 
     
     
         7 . The improvement of  claim 6  wherein the at least one tie is in tension and the elastic outer spacer is in compression. 
     
     
         8 . In a medical implant assembly having at least two bone attachment structures cooperating with a longitudinal connecting member, the improvement wherein the connecting member comprises:
 a transition portion disposed between the bone attachment structures, the transition portion having   a) at least one substantially rigid portion with at least a pair of spaced apertures; and   b) at least one elongate tie extending through the apertures, the tie being in tension prior to attachment of the rigid portion to the bone attachment structure.   
     
     
         9 . The improvement of  claim 8  wherein the at least one substantially rigid portion is a first rigid portion having a plurality of apertures and further comprising a second rigid portion having at least a second aperture, the at least one tie extending through each of the apertures. 
     
     
         10 . The improvement of  claim 8  wherein the at least one rigid portion has a plurality of apertures and further comprising a plurality of ties, each tie extending through an aperture. 
     
     
         11 . The improvement of  claim 9  wherein both the first and second rigid portions have a plurality of apertures and further comprising a plurality of ties, each tie extending through one aperture of the first rigid portion and one aperture of the second portion, the ties forming discrete loops. 
     
     
         12 . The improvement of  claim 9  wherein the first rigid portion is an elongate rod. 
     
     
         13 . The improvement of  claim 9  wherein both the first and second rigid portions are each elongate rods. 
     
     
         14 . The improvement of  claim 9  further comprising a compressible spacer at the transition portion. 
     
     
         15 . In a medical implant assembly having at least first and second bone anchors cooperating with a longitudinal connecting member, the improvement wherein the connecting member comprises:
 a) first and second rigid ends, the first rigid end coupled to the first bone anchor, the first rigid end extending completely through the first bone anchor; the second rigid end coupled to the second bone anchor, the second rigid end extending completely through the second bone anchor;   b) a pre-tensioned non-metallic flexible core positioned between the first and second rigid ends and coupled to both the first and second rigid ends; and   c) a pre-compressed elastomer completely surrounding the flexible core.   
     
     
         16 . The improvement of  claim 15  wherein the first rigid end has an integral plate with at least a pair of apertures and the flexible core is at least one tie looped through the apertures. 
     
     
         17 . The improvement of  claim 15  wherein both the first rigid end and the second rigid end each have a plurality of apertures and the flexible core is at least one tie extending through each of the apertures. 
     
     
         18 . The improvement of  claim 15  wherein the first rigid end has a plurality of apertures and the flexible core comprises a plurality of ties, each tie extending through an aperture. 
     
     
         19 . The improvement of  claim 18  wherein the second rigid end has a plurality of apertures and each tie extends through at least one aperture of the first rigid end and one aperture of the second rigid end, the ties forming discrete loops. 
     
     
         20 . The improvement of  claim 19  wherein the first rigid end includes an elongate rod integral with a radially extending plate, the plate having the plurality of apertures.