Flexible linking piece for stabilising the spine

Abstract

Embodiments described herein relate to a connecting member for maintaining the spacing between at least two anchor members screwed into vertebrae and methods for stabilizing the spine using a connecting member. One embodiment of a connecting member can include a first rigid portion formed of a first material, a second rigid portion formed of the first material and a connecting body comprising a second material that is more elastically deformable than the first material.

1 . A method of stabilizing a spinal segment of a body comprising:
 securing a first anchor to a first vertebra, the first anchor including a head portion and a bone attachment portion;   securing a second anchor to a second vertebra, the second anchor including a head portion and a bone attachment portion;   implanting a connecting member into the body, wherein the connecting member comprises:
 a first rigid portion formed of a first material comprising;
 a first rod portion adapted to secure in a head portion of a first anchor; and 
 a first wall having a larger radius than the first rod portion; 
 
 a second rigid portion formed of the first material comprising:
 a second rod portion adapted to secure in a head portion of a second anchor; and 
 a second wall having a larger radius than the second rod portion; and 
 
 a connecting body having a first end abutting the first wall and a second end abutting the second wall, wherein the connecting body comprises a second material that is more elastically deformable than the first material; 
   positioning the connecting body between the head portion of the first anchor and the head portion of the second anchor; and   positioning the first rigid portion within the head portion of the first anchor and the second rigid portion in the head portion of the second anchor.   
   
   
       2 . The method of  claim 1 , wherein the first wall and second wall each comprise at least one protrusion that abuts the connecting body. 
   
   
       3 . The method of  claim 2 , wherein the first rigid portion partially overlaps said connecting body. 
   
   
       4 . The method of  claim 1 , wherein the first rigid portion defines an opening passing from the first wall through the first rigid portion and open to an end of the first rod portion and the second rigid portion defines an opening passing from the second wall through the second rigid rod portion and open to and of the second rod portion. 
   
   
       5 . The method of  claim 1 , further comprising positioning the first rigid portion and second rigid portion from the top of the first anchor and second anchor respectively. 
   
   
       6 . The method of  claim 1 , further comprising:
 securing the first rigid portion to the head portion of the first anchor by engaging a first locking member to a the head portion of the first anchor; and   securing the second rigid portion to the head portion of the second anchor by engaging a second locking member to a the head portion of the second anchor;   
   
   
       7 . The method of  claim 1 , wherein the head portion of each of the first and second anchors includes a slot adapted to receive the first rigid portion and second rigid portion respectively. 
   
   
       8 . The method of  claim 1 , wherein the connecting body has a greater cross-sectional area than the first rod portion and the second rod portion. 
   
   
       9 . The method of  claim 7 , wherein the first rigid portion and second rigid portion are formed of a biocompatible metal and the connecting body comprises a polymer. 
   
   
       10 . A connecting member comprising:
 a first rigid portion formed of a first material comprising;
 a first portion adapted to secure in a head portion of a first anchor; and 
 a first wall having a larger radius than the first rod portion; 
   a second rigid portion formed of the first material comprising:
 a second portion adapted to secure in a head portion of a second anchor; and 
 a second wall having a larger radius than the second rod portion; and 
 a connecting body having a first end abutting the first wall and a second end abutting the second wall, wherein the connecting body comprises a second material that is more elastically deformable than the first material. 
   
   
   
       11 . The connecting member of  claim 10 , wherein the first wall and second wall each comprise at least one protrusion that abuts the connecting body. 
   
   
       12 . The connecting member of  claim 11 , wherein the first rigid portion partially overlaps said connecting body. 
   
   
       13 . The connecting member of  claim 10 , wherein the first rigid portion defines an opening passing from the first wall through the first rigid portion and open to an end of the first rod portion and the second rigid portion defines an opening passing from the second wall through the second rigid rod portion and open to and of the second rod portion. 
   
   
       14 . The connecting member of  claim 10 , wherein the first material is a biocompatible metal and the second material is a polymer. 
   
   
       15 . The connecting member of  claim 10 , wherein the connecting body is substantially symmetrical about a longitudinal axis. 
   
   
       16 . The connecting member of  claim 10 , wherein the first rigid portion and the second rigid portion are cylindrical. 
   
   
       17 . A spinal stabilization system comprising:
 a first anchor coupled to a first vertebra, the first anchor having a head portion;   a second anchor coupled to a second vertebra, the second anchor having a head portion;   a connecting member comprising:
 a first rigid portion formed of a first material comprising;
 a first portion secured in a head portion of a first anchor; and 
 a first wall having a larger radius than the first rod portion; 
 
 a second rigid portion formed of the first material comprising:
 a second portion secured in a head portion of a second anchor; and 
 a second wall having a larger radius than the second rod portion; and 
 
 a connecting body having a first end abutting the first wall and a second end abutting the second wall, wherein the connecting body comprises a second material that is more elastically deformable than the first material. 
   
   
   
       18 . The spinal stabilization system of  claim 17 , wherein the first wall and second wall each comprise at least one protrusion that abuts the connecting body. 
   
   
       19 . The spinal stabilization system of  claim 18 , wherein the first rigid portion partially overlaps said connecting body. 
   
   
       20 . The spinal stabilization system of  claim 17 , wherein the first rigid portion defines an opening passing from the first wall through the first rigid portion and open to an end of the first rigid portion and the second rigid portion defines an opening passing from the second wall through the second rigid portion and open to an end of the second rigid portion.