Spinal Fixation Constructs and Related Methods

Abstract

This disclosure describes a variety of transitional or terminal components that may be implanted as part of a spinal fixation construct to decrease the potential for subsequent development of junctional disease. The fixation construct may extend any number of levels from a single level construct to a long construct spanning multiple spinal levels and multiple spinal regions from the lumbosacral to cervical regions, and with any variety of combination of anchors, rods, and connectors. Terminal and/or transitional components maybe utilized at the caudal and or cephalad ends of the fixation construct to reduce stresses endured by the construct adjacent pathology and prevent or reduce incidence and degree of junctional disease.

What is claimed is: 
     
         1 . A rod attachment for securing a spinal rod to a bone structure, the rod attachment comprising:
 a first side, a second side, and a lumen extending longitudinally along a first axis through the first side and the second side of the rod attachment, the lumen dimensioned to receive the spinal rod and wherein the first lumen is configured to allow the spinal rod to enter from the first side and exit the lumen from the second side;   a third side of the rod attachment including at least one aperture, wherein the at least one aperture intersects the lumen along a second axis about perpendicular to the first axis; and   a fourth side of the rod attachment including a tether connector, wherein the tether connector is configured to receive a tether parallel to and offset from the second axis.   
     
     
         2 . The rod attachment of  claim 1 , wherein the lumen has an enclosed perimeter. 
     
     
         3 . The rod attachment of  claim 1 , wherein the rod attachment further comprises: a housing section that contains the lumen, the at least one aperture, and the tether connector. 
     
     
         4 . The rod attachment of  claim 1 , wherein the tether connector comprises:
 a post member extending outwardly from the fourth side; and   a second lumen extending through the post member.   
     
     
         5 . The rod attachment of  claim 4 , wherein the lumen does not intersect the second lumen. 
     
     
         6 . The rod attachment of  claim 1 , wherein the rod attachment further comprises:
 at least one locking element in the at least one aperture.   
     
     
         7 . The rod attachment of  claim 6 , wherein the at least one aperture comprises an aperture screw thread, wherein the at least one locking element comprises a locking screw thread, and wherein the aperture screw thread and the locking screw thread are complementary. 
     
     
         8 . The rod attachment of  claim 7 , wherein the aperture screw thread is configured to engage with the locking screw thread as the at least one locking element is advanced via rotation in the at least one aperture. 
     
     
         9 . A rod attachment for securing a spinal rod to a bone structure, the rod attachment comprising:
 a first side, an second side and a first lumen extending longitudinally through the first side of the rod attachment and the second side of the rod attachment, wherein the first lumen is dimensioned to receive the spinal rod and configured to allow the spinal rod to enter from the first side and exit the first lumen from the second side;   a third side having a first aperture and a second aperture, wherein the first aperture and the second aperture each intersect the first lumen; and   a fourth side including a tether connector, wherein the tether connector comprises a post member extending outwardly from the fourth side, wherein the post member comprises a second lumen dimensioned to receive a tether.   
     
     
         10 . The rod attachment of  claim 9 , wherein the rod attachment further comprises: a housing section that contains the first lumen, the first aperture, the second aperture, and the tether connector. 
     
     
         11 . The rod attachment of  claim 9 , wherein the first lumen does not intersect the second lumen. 
     
     
         12 . The rod attachment of  claim 9 , wherein the rod attachment further comprises:
 a first locking element in the first aperture; and   a second locking element in the second aperture.   
     
     
         13 . The rod attachment of  claim 12 , wherein the first and second apertures comprise aperture screw threads, wherein the first and second locking elements comprise locking screw threads, and wherein the aperture screw threads and the locking screw threads are complementary. 
     
     
         14 . A bone anchor for securing a spinal rod to a bone structure, the bone anchor comprising:
 a threaded shank; and   a housing comprising:
 a base coupled to the threaded shank; 
 a pair of upstanding arms spaced apart forming a channel dimensioned to fit a portion of the spinal rod; and 
 a tether connector on a given arm of the pair of upstanding arms. 
   
     
     
         15 . The bone anchor of  claim 14 , wherein the housing is coupled to the threaded shank in a multi-axial configuration in which the housing can rotate and pivot relative to the threaded shank. 
     
     
         16 . The bone anchor of  claim 14 , wherein the tether connector comprises:
 a post member extending outwardly from the given arm; and   a lumen extending through the post member.   
     
     
         17 . The bone anchor of  claim 16 , wherein the channel does not intersect the lumen. 
     
     
         18 . The bone anchor of  claim 14 , wherein the bone anchor further comprises:
 a locking element that is attachable to the housing between the pair of upstanding arms.   
     
     
         19 . The bone anchor of  claim 18 , wherein the locking element comprises an upper portion that mates with the pair of upstanding arms and a lower portion that engages with a given portion of the spinal rod. 
     
     
         20 . The bone anchor of  claim 18 , wherein each arm of the pair of upstanding arms comprises a locking engagement feature configured to engage with a housing engagement feature of the locking element as the locking element is advanced via rotation between the pair of upstanding arms.