Posterior stabilization systems with shared, dual dampener systems

Abstract

Dynamic posterior stabilization systems and methods of stabilizing vertebrae are described. A dynamic posterior stabilization system may include a first bone fastener configured to couple to a first vertebra, a second bone fastener configured to couple to a second vertebra, and a dampener system attached to the first bone fastener and the second bone fastener. The dampener system may include a first dampener set and a second dampener set. Compression of the first dampener set provides resistance to movement of the first bone fastener towards the second bone fastener. Compression of the first dampener set and the second dampener set provides resistance to movement of the first bone fastener away from the second bone fastener.

1 - 147 . (canceled) 
     
     
         148 . A dynamic stabilization system, comprising:
 a first bone fastener configured to couple to a first vertebra;   a second bone fastener configured to couple to a second vertebra; and   a dampener system comprising:
 a first portion; 
 an adjustable member configured to couple the first portion to the first bone fastener; 
 a first dampener set; 
 a second dampener set; and 
 a second portion configured to couple to the second bone fastener, 
   wherein the adjustable member is configured to translate along a length of the first portion to adjust an effective length of a portion of the dampener system spanning the distance between the first and second bone fastener.   
     
     
         149 . The system of  claim 148 , wherein the adjustable member comprises a thread configured to engage a complementary thread disposed along the first portion of the dampener system. 
     
     
         150 . The system of  claim 148 , wherein the adjustable member is configured to translate to a position along the length of the first portion such that when the human spine is in a neutral position the first dampener set and the second dampener set experience substantially no compression during use. 
     
     
         151 . The system of  claim 148 , wherein the adjustable member is configured to couple the first portion to the first bone fastener allowing rotation and polyaxial movement of the dampener system relative to the first bone fastener. 
     
     
         152 . The method of  claim 148 , wherein the adjustable member is configured to couple the first portion to the first bone fastener allowing rotation and polyaxial movement of the dampener system relative to the first bone fastener, wherein the adjustable member is substantially spherical and at least partially disposed in a complementary portion coupled to the bone fastener. 
     
     
         153 . The system of  claim 148 , wherein compression of the first dampener set is configured to provide resistance to movement of the first bone fastener towards the second bone fastener during use, wherein compression of the first dampener set is configured to provide resistance to movement of first bone fastener away from the second bone fastener during use, and wherein compression of the second dampener set is configured to provide resistance to movement of first bone fastener away from the second bone fastener during use. 
     
     
         154 . The system of  claim 148 , wherein the dampener system comprises an elongated member, wherein the elongated member comprises the first portion and the second portion, and wherein the first portion is configured to move relative to the second portion. 
     
     
         155 . The system of  claim 148 , wherein the first dampener set comprises a plurality of dampeners. 
     
     
         156 . The system of  claim 148 , wherein the first dampener set comprises a dampener with large and small diameter sections. 
     
     
         157 . The system of  claim 148 , further comprising a sleeve configured to couple the second portion to the second bone fastener. 
     
     
         158 . The system of  claim 148 , further comprising an offset member configured to couple the second portion to the second bone fastener. 
     
     
         159 . The system of  claim 148 , further comprising a first washer having a convex surface and a second washer having a convex surface, wherein the convex surface of the first washer and the convex surface of the second washer are configured to engage recesses in a collar of the second bone fastener. 
     
     
         160 . The system of  claim 148 , wherein the first dampener set comprises an elastic dampener member and wherein the second dampener set comprises an elastic dampener member. 
     
     
         161 . The system of  claim 160 , wherein each of the first and second dampener sets comprises a first rigid member configured to be disposed on a first side of the elastic dampener member and a second rigid member configured to be disposed on a second side of the elastic dampener member that is opposite from the first side during use such that the first and second rigid members sandwich the respective elastic dampener members. 
     
     
         162 . The system of  claim 148 , wherein the first dampener set is configured to be disposed between a head portion of the first bone fastener and a head portion of the second bone fastener during use, and wherein the second dampener set is configured to be disposed on an opposite side of the head portion of the second bone fastener from the first dampener set during use. 
     
     
         163 . A method of stabilizing a portion of a human spine, comprising:
 securing a first bone fastener to a first vertebra of a human spine;   securing a second bone fastener to a second vertebra of the human spine; and   coupling a dampener system to the first bone fastener and the second bone fastener, comprising coupling an adjustable member to the first bone fastener or the second bone fastener, wherein the adjustable member is coupled to a first portion of an elongated member of the dampener system, wherein the adjustable member is capable of translating along a length of the first portion of the elongated member to adjust an effective length of the elongated member spanning the distance between the first and second bone fastener, and wherein the dampener system comprises a first dampener set and a second dampener set positioned on the elongated member.   
     
     
         164 . The method of  claim 163 , wherein the adjustable member comprises a thread configured to engage a complementary thread disposed along at least the portion of the elongated member. 
     
     
         165 . The method of  claim 163 , further comprising: translating the adjustable member along a length of the first portion of the elongated member such that the elongated member has a desired effective length for spanning a distance between the first and second bone fastener. 
     
     
         166 . The method of  claim 163 , further comprising: translating the adjustable member to a position along a length of the first portion of the elongated member such that when the human spine is in a neutral position the first dampener set and the second dampener set experience substantially no compression. 
     
     
         167 . The method of  claim 163 , further comprising: allowing rotation and polyaxial movement of the elongated member relative to the first or second bone fastener which is coupled to the adjustable member. 
     
     
         168 . The method of  claim 163 , further comprising: allowing rotation and polyaxial movement of the elongated member relative to the first or second bone fastener which is coupled to the adjustable member, wherein the adjustable member is substantially spherical and disposed in a complementary portion coupled to the bone fastener. 
     
     
         169 . The method of  claim 163 , further comprising: resisting movement of the first bone fastener away from the second bone fastener by compressing the first dampener set and the second dampener set during use. 
     
     
         170 . The method of  claim 163 , further comprising: resisting movement of the first bone fastener towards the second bone fastener by compressing the first dampener set during use. 
     
     
         171 . The method of  claim 163 , further comprising securing at least one dynamic interbody device between the first vertebra and the second vertebra. 
     
     
         172 . The method of  claim 163 , wherein the first dampener set comprises an elastic dampener member, and wherein the second dampener set comprises an elastic dampener member. 
     
     
         173 . The method of  claim 172 , further comprising:
 moving the first bone fastener towards the second bone fastener such that the first and second rigid members of the first dampener set move toward one another to compress the elastic dampener of the first dampener set during use, and   moving the first bone fastener away from the second bone fastener such that the first and second rigid members of the first dampener set move toward one another during use and the first and second rigid members of the second dampener set move toward one another during use to compress the respective elastic dampeners of the first and second dampener sets during use.   
     
     
         174 . The method of  claim 163 , further comprising:
 disposing the first dampener set between a head portion of the first bone fastener and a head portion of the second bone fastener during use; and   disposing the second dampener set on an opposite side of the head portion of the second bone fastener from the first dampener set during use.