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, a second rigid portion and a connecting body disposed between the first rigid body and the second rigid body that is more flexible than the first rigid body and the second rigid body. The connecting member can be provided as a preassembled connecting member.

1 . A method of stabilizing a spinal segment of a body comprising:
 providing a connecting member comprising a first rigid portion, a second rigid portion and connecting body disposed between the first rigid portion and the second rigid portion to form a preassembled connecting member, wherein the connecting body is more flexible than the first rigid portion and the second rigid portion;   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;   inserting the preassembled connecting member into the body to the spinal segment;   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 assembling further comprises securing the connecting body between the first rigid portion and the second rigid portion. 
   
   
       3 . The method of  claim 1 , further comprising:
 securing the first rigid portion to the head portion of the first anchor by engaging a locking member to 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 the head portion of the second anchor.   
   
   
       4 . 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. 
   
   
       5 . The method of  claim 1 , wherein:
 the first rigid portion comprises:
 a first rod portion adapted to be secured in the head of the first anchor; 
 a first wall; 
   the second rigid portion comprises:
 a second rod portion adapted to be secured in the head of the second anchor; 
 a second wall; 
   wherein the connecting member abuts the first wall and the second wall and is secured between the first wall and the second wall.   
   
   
       6 . The method of  claim 5 , wherein the connecting body has a greater cross-sectional area than the first rod portion and the second rod portion. 
   
   
       7 . The method of  claim 5 , wherein the first rigid portion and second rigid portion partially overlap said connecting body. 
   
   
       8 . The method of  claim 5 , wherein the first rod portion and second rod portions are formed of a biocompatible metal and the connecting body comprises a polymer. 
   
   
       9 . The method of  claim 5 , 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. 
   
   
       10 . The method of  claim 5 , wherein the first wall and second wall each comprise at least one protrusion that abuts the connecting body. 
   
   
       11 . The method of  claim 1 , wherein the connecting member is formed by injecting the connecting body between the first rigid portion and the second rigid portion. 
   
   
       12 . 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; 
   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; and 
   a connecting body secured between the first wall and the second wall, wherein the connecting body comprises a second material that is more elastically deformable than the first material;   wherein the connecting member is adapted to be inserted into the body as a preassembled connecting member.   
   
   
       13 . The connecting member of  claim 12 , wherein the first material is a biocompatible metal and the second material is a polymer. 
   
   
       14 . The connecting member of  claim 12 , wherein the connecting body is substantially symmetrical about a longitudinal axis. 
   
   
       15 . The connecting member of  claim 14 , wherein the first rigid portion and the second rigid portion are cylindrical. 
   
   
       16 . The connecting member of  claim 14 , wherein the connecting body has a greater radius than the first portion and the second portion. 
   
   
       17 . The connecting member of  claim 12 , wherein the first rigid portion and second rigid portion partially overlap the connecting body. 
   
   
       18 . The connecting member of  claim 12 , 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 portion and the second rigid portion defines an opening passing from the second wall through the second rigid portion and open to and of the second rod portion. 
   
   
       19 . The connecting member of  claim 12 , wherein the first wall and second wall each comprise at least one protrusion that abuts the connecting body. 
   
   
       20 . A method of stabilizing a spinal segment of a body comprising:
 forming, outside of the body, 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; 
 
 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; and 
 
 a connecting body secured between the first wall and the second wall, wherein the connecting body comprises a second material that is more elastically deformable than the first material; 
   inserting the connecting member into the body;   positioning the connecting body between a head portion of a first anchor and a head portion of a second anchor; and   positioning the first portion within the head portion of the first anchor from the top of the first anchor and the second portion in the head portion of the second anchor from the top of the second portion.   
   
   
       21 . The method of  claim 20 , wherein the first rigid portion and second rigid portion partially overlap said connecting body. 
   
   
       22 . The method of  claim 20 , 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 portion and the second rigid portion defines an opening passing from the second wall through the second rigid portion and open to and of the second portion.