Method and apparatus for flexible fixation of a spine

Abstract

A flexible spinal fixation device having a flexible connection unit for non-rigid stabilization of the spinal column. In one embodiment, the fixation device includes at least two securing members configured to be inserted into respective adjacent spinal pedicles, each securing member each including a coupling assembly. The fixation device further includes a flexible connection unit configured to be received and secured within the coupling assemblies of each securing member so as to flexibly stabilize the affected area of the spine.

1 . A flexible connection unit for use in a spinal fixation device, the flexible connection unit comprising a longitudinal member having at least one groove formed along at least a portion of the longitudinal member thereby providing additional flexibility to the longitudinal member.  
     
     
         2 . The flexible connection unit of  claim 1  wherein the longitudinal member comprises a solid rod.  
     
     
         3 . The flexible connection unit of  2  wherein the solid rod comprises a solid metal rod.  
     
     
         4 . The flexible connection unit of  claim 1  wherein the at least one groove has a depth between 1 and 5 millimeters and a width between 0.1 and 2.0 millimeters.  
     
     
         5 . The flexible connection unit of  claim 1  wherein the at least one groove is formed in a spiral configuration along a longitudinal axis of the longitudinal member.  
     
     
         6 . The flexible connection unit of  claim 5  wherein the at least one groove is formed at a spiral angle θ from horizontal between 30 and 89 degrees.  
     
     
         7 . The flexible connection unit of  claim 1  further including at least one transverse tunnel formed within at least a portion of the longitudinal member.  
     
     
         8 . The flexible connection unit of  claim 7  wherein the longitudinal member comprises a solid rod cylindrical in shape and the at least one transverse tunnel passes through the cylindrical rod such that respective openings for the at least one transverse tunnel are located on opposing side surfaces of the cylindrical rod.  
     
     
         9 . The flexible connection unit of  claim 8  wherein the at least one transverse tunnel comprises a plurality of transverse tunnels and each transverse tunnel passes through a center longitudinal axis of the cylindrical rod at a predetermined angle Φ and wherein adjacent transverse tunnels share a common opening on one side of a cylindrical wall, forming a zigzag pattern of interior tunnels passing transversely through the central longitudinal axis of the rod.  
     
     
         10 . The flexible connection unit of  claim 9  wherein the location of the common openings intersect with respective portions of the at least one groove at an exterior surface of the rod.  
     
     
         11 . The flexible connection unit of  claim 1  wherein the longitudinal member comprises a cylindrical tube.  
     
     
         12 . The flexible connection unit of  11  wherein the cylindrical tube comprises a metal cylindrical tube.  
     
     
         13 . The flexible connection unit of  claim 11  further comprising a rod having a smaller diameter than the cylindrical tube such that the rod is configured to fit inside a longitudinal axial channel of the cylindrical tube.  
     
     
         14 . The flexible connection unit of  claim 13  wherein the rod comprises a solid rod.  
     
     
         15 . The flexible connection unit of  claim 14  wherein the solid rod is made from a flexible core material selected from a group consisting of: carbon graphite, PEEK, PEEKEK, NITINOL, and UHMWPE.  
     
     
         16 . The flexible connection unit of  claim 14  wherein the solid rod comprises a second groove formed thereon for providing additional flexibility to the solid rod.  
     
     
         17 . The flexible connection unit of  claim 13  wherein the rod comprises a second tube.  
     
     
         18 . The flexible connection unit of  claim 17  wherein the second tube is made from a flexible core material selected from a group consisting of: carbon graphite, PEEK, PEEKEK, NITINOL, and UHMWPE.  
     
     
         19 . The flexible connection unit of  claim 17  wherein the second tube comprises a second groove formed thereon for provided additional flexibility to the second tube.  
     
     
         20 . The flexible connection unit of  claim 1  wherein the longitudinal member is configured in the shape of a cylindrical rod.  
     
     
         21 . The flexible connection unit of  claim 20  wherein the cylindrical rod has a substantially uniform outer diameter along its longitudinal axis.  
     
     
         22 . The flexible connection unit of  claim 1  wherein the portion of the longitudinal member having at least one groove has a cross-sectional area that is different from respective end portions of the longitudinal member.  
     
     
         23 . A flexible connection unit for use in a spinal fixation device comprising a solid longitudinal member and at least one transverse tunnel formed within the solid longitudinal member so as to provide flexibility to the longitudinal member.  
     
     
         24 . The flexible connection unit of  claim 23  wherein the solid longitudinal member comprises a cylindrical rod and the at least one transverse tunnel passes through a center longitudinal axis of the cylindrical rod such that respective openings for the at least one transverse tunnel are located on opposite sides of a cylindrical wall of the rod.  
     
     
         25 . The flexible connection unit of  claim 23  wherein the at least one transverse tunnel comprises a plurality of transverse tunnels, each transverse tunnel intersecting a center longitudinal axis of the longitudinal member at a predetermined angle Φ and wherein adjacent transverse tunnels share a common opening at a lateral surface of the longitudinal member, forming a zigzag pattern of interior tunnels intersecting the center longitudinal axis of the longitudinal member.  
     
     
         26 . A flexible connection unit for use in a spinal fixation device comprising: 
 a longitudinal member configured to be secured to a patient's spine using at least three securing members;    wherein a first portion of the longitudinal member is configured to be located between a first pair of securing members and a second portion of the longitudinal member is configured to be located between a second pair of securing members; and    wherein at least one of the first and second portions comprises a groove formed therein for providing flexibility to the at least one of the first and second portions.    
     
     
         27 . The flexible connection unit of  claim 26  wherein the longitudinal member comprises a cylindrical rod and the groove comprises a spiral groove formed along a longitudinal axis of the at least one of the first and second portions.  
     
     
         28 . The flexible connection unit of  claim 26  wherein each of the first and second portions comprises a groove formed therein for providing flexibility thereto.  
     
     
         29 . The flexible connection unit of  claim 28  wherein the grooves formed in the first and second portions each comprise a spiral groove formed around a respective longitudinal axis of the first and second portions.