Method and associated instrumentation for installation of spinal dynamic stabilization system

Abstract

In one embodiment, a spinal stabilization apparatus includes a vertebral anchor having a head portion and a bone attachment portion. An elongate, flexible guide is removably coupled to the head portion of the vertebral anchor and has a channel extending longitudinally thereof and communicating with a slot in the head portion of the anchor. An elongate cord may be received within the channel to facilitate inserting and securing a spacer between pairs of anchors installed into adjacent vertebrae of a person's spine.

What is claimed is: 
     
       1. A method of installing a spinal stabilization construct, comprising:
 installing first and second vertebral anchors onto first and second vertebrae, respectively, each vertebral anchor having an upwardly open channel adapted to receive a flexible connecting element extending between the first and second vertebrae; 
 mounting first and second access members onto the first and second vertebral anchors, respectively, each access member having a cannula to provide access to the channel of the respective vertebral anchor; 
 inserting the connecting element through a slot in the first access member; 
 advancing the flexible connecting element from the slot in the first access member into the channel of the first vertebral anchor; 
 securing the flexible connecting element to within the channel of the first vertebral anchor with a first fastener; 
 positioning a spacer on the connecting element adjacent the first vertebral anchor; 
 inserting the flexible connecting element through a slot in the second access member; 
 translating a tool along an exterior of the second access member without rotation to advance the flexible connecting element along the slot in the second access member into the channel in the second vertebral anchor; 
 positioning the spacer between the vertebral anchors; and 
 securing the flexible connecting element to within the channel of the second vertebral anchor with a second fastener. 
 
     
     
       2. The method of  claim 1 , wherein positioning the spacer between the vertebral anchors includes:
 pushing the spacer into position between the vertebral anchors with the tool. 
 
     
     
       3. The method of  claim 2 , wherein the tool includes a lateral portion extending transverse to a longitudinal axis of the tool for contacting the spacer. 
     
     
       4. The method of  claim 3 , wherein the lateral portion is a flange including an arcuate surface. 
     
     
       5. The method of  claim 4 , wherein the arcuate surface contacts an outer surface of the spacer. 
     
     
       6. The method of  claim 1 , wherein the tool is a tubular member slidably disposed around the second access member. 
     
     
       7. The method of  claim 1 , further comprising:
 tensioning the connecting element after securing the flexible connecting element to the channel of the first vertebral anchor and prior to securing the flexible connecting element to the channel of the second vertebral anchor. 
 
     
     
       8. The method of  claim 1 , further comprising:
 distracting the first and second vertebrae during positioning of the spacer between the vertebral anchors. 
 
     
     
       9. The method of  claim 1 , wherein securing the flexible connecting element to the channel of the first vertebral anchor with the first fastener includes passing the first fastener through the first access member percutaneously to the first vertebral anchor, and securing the flexible connecting element to the channel of the second vertebral anchor with the second fastener includes passing the second fastener through the second access member percutaneously to the second vertebral anchor. 
     
     
       10. A method for performing spinal stabilization surgery, comprising:
 creating at least one access opening in a patient;   implanting, through the at least one access opening, a plurality of vertebral anchors into a plurality of corresponding vertebrae, each vertebral anchor having an upwardly open channel defined between upwardly directed arms, the channel configured to receive a flexible cord in a top loading manner;   top loading the cord into the channel of a first vertebral anchor of the plurality of vertebral anchors using a cord guide tool having a cord guide feature and a vertebral anchor feature;   securing a first end portion of the cord to the first vertebral anchor;   engaging a second vertebral anchor of the plurality of vertebral anchors with the cord guide tool through the at least one access opening;   using the cord guide tool to advance the cord distally into the channel of the second vertebral anchor subsequent to engagement with the second vertebral anchor and prior to fixation of the cord in the second vertebral anchor;   engaging a tensioning tool to the cord guide tool;   translating the second vertebral anchor implanted into a second vertebra relative to the first vertebral anchor implanted into a first vertebra using vertebral anchor feature of the cord guide tool;   applying a tension to the cord using the tensioning tool; and   securing the cord to the second vertebral anchor by rotating a set screw into securement in the channel of the second vertebral anchor with a driver;   wherein the securing step is performed while the cord guide tool is engaged with the second vertebral anchor at the vertebral anchor feature after being slid over an access tool coupled to the second vertebral anchor.   
     
     
       11. The method of claim 10, further comprising:
 positioning the driver through a lumen of the cord guide tool to rotate the set screw.   
     
     
       12. The method of claim 11, wherein the tensioning tool is engaged at a proximal end region of the cord guide tool and the cord passes through an opening in the cord guide tool at least partially defining the cord guide feature to reach the tensioning tool. 
     
     
       13. The method of claim 12, wherein the driver is positioned in the lumen of the cord guide tool while the tensioning tool is engaged at a proximal end region of the cord guide tool. 
     
     
       14. The method of claim 13, wherein the tensioning tool is offset from the lumen of the cord guide. 
     
     
       15. The method of claim 10, wherein a portion of the cord extends from the second vertebral anchor to the tensioning tool. 
     
     
       16. A method for performing spinal stabilization surgery, comprising:
 implanting first and second vertebral anchors into first and second vertebral bodies, respectively, each vertebral anchor having an upwardly open channel defined between upwardly directed arms, the channel configured to receive a flexible cord in a top loading manner;   advancing the cord distally into the channel the first vertebral anchor;   securing a first end portion of the cord to the first vertebral anchor;   engaging the second vertebral anchor with a cord guide tool;   using the cord guide tool to both advance the cord distally into the channel of the second vertebral anchor with a cord guide feature and translate the second vertebral anchor relative to the first vertebral anchor with a vertebral anchor feature prior to fixation of the cord in the second vertebral anchor, wherein translating the second vertebral anchor involves application of force to the cord guide tool to manipulate the position of the second vertebral body;   engaging a tensioning tool to a proximal end of the cord guide tool;   applying a tension to the cord using the tensioning tool;   positioning a driver through a lumen of the cord guide tool; and   securing the cord to the second vertebral anchor while the cord guide tool is engaged with the second vertebral anchor at the vertebral anchor feature after being slid over an access tool coupled to the second vertebral anchor.   
     
     
       17. The method of claim 16, wherein the driver is positioned in the lumen of the cord guide tool while the tensioning tool is engaged with the cord guide tool. 
     
     
       18. The method of claim 17, wherein the tensioning tool is offset from the lumen of the cord guide tool. 
     
     
       19. The method of claim 18, wherein a portion of the cord extends from the second vertebral anchor to the tensioning tool.