Percutaneous access devices and bone anchor assemblies

Abstract

A percutaneous access device includes an inner tube and an outer tube disposed about at least a portion of the inner tube. The outer tube may be sized to span from a skin incision in a patient to a site proximate the spine of the patient. The distal end of the outer tube may be adapted to releasably engage a bone anchor. The inner tube may be adjustable relative to the outer tube between a first position and a second position in which the distal end of the inner tube contacts the bone anchor. A bone anchor assembly includes a bone anchor having a distal bone engaging portion and a receiving member having a recess for receiving a spinal fixation element. The proximal end of the receiving member may have an arcuate groove formed on an exterior surface thereof to facilitate connection of an instrument to the receiving member.

1 .- 46 . (canceled) 
     
     
         47 . An elongate guide tool in combination with a spinal bone screw implant, the guide tool being reversibly attachable to the bone screw for guiding a rod into a receiver of the bone screw, the guide tool comprising:
 a) a body with a longitudinally extending through-bore extending from a top opening to a bottom opening, the through-bore being sized and shaped for receiving a closure top therethrough;   b) a laterally extending pass-through slot extending upwardly from the bottom opening and joined with the through-bore, the pass-through slot defining a pair of spaced opposed legs and being sized and shaped so as to receive the rod therethrough, the pass-through slot being alignable with a U-shaped channel of the bone screw receiver; and   c) a first inwardly projecting attachment structure near the bottom opening that is sized and shaped to cooperatively engage a second attachment structure of the bone screw receiver when the guide tool is secured to the bone screw, wherein the second attachment structure is a radiused horizontal groove circumferentially located on an exterior of the receiver, the second attachment structure having an abutment surface, thereby preventing rotation of the guide tool relative to the receiver; wherein   d) when the pass-through slot and the U-shaped channel are aligned, the rod is transferable from the guide tool to the bone screw.   
     
     
         48 . The guide tool according to  claim 47 , wherein the guide tool further comprises:
 a) a cutout sized, shaped and positioned so as to straddle the rod when the guide tool is rotated such that the pass-through slot and the U-shaped channel are not aligned.   
     
     
         49 . The guide tool according to  claim 47 , wherein each of the legs comprises:
 a) an inner surface comprising the first attachment structure.   
     
     
         50 . The guide tool according to  claim 47 , wherein each of the legs comprises:
 a) an inner surface of the through-bore having a portion of a guide and advancement structure thereon.   
     
     
         51 . The guide tool according to  claim 47 , wherein:
 a) the first attachment structure reversibly engages the second attachment structure upon rotation of the guide tool relative to a head of the bone screw.   
     
     
         52 . The guide tool according to  claim 51 , wherein:
 a) the first and second attachment structures cooperate so as to substantially align the pass-through slot and the U-shaped channel such that the rod is transferable therebetween.   
     
     
         53 . The guide tool according to  claim 47 , wherein:
 a) the body includes upper, middle and lower portions; and   b) the pass-through slot extends from the lower portion toward the middle portion.   
     
     
         54 . The guide tool according to  claim 47 , wherein:
 a) each leg includes an inner surface with an inwardly extending first attachment structure; and   b) the first attachment structure includes an off-set detent sized and shaped so as to be cooperatively rotatably received by the bone screw second attachment structure.   
     
     
         55 . The guide tool according to  claim 54 , wherein:
 a) the bone screw second attachment structure is an off-axis partially circumferential slot sized and shaped to reversibly engage the off-set detent.   
     
     
         56 . The guide tool according to  claim 47 , wherein:
 a) each leg includes an inner surface with an inwardly extending first attachment structure;   b) the first attachment structure includes an off-set cam sized and shaped so as to be cooperatively rotatably received by the bone screw second attachment structure.   
     
     
         57 . The guide tool according to  claim 56 , wherein:
 a) the bone screw second attachment structure is a camming groove sized and shaped to reversibly engage the off-set cam.   
     
     
         58 . The guide tool according to  claim 47 , wherein:
 a) each leg includes an inner surface with an inwardly extending first attachment structure;   b) the first attachment structure includes an inwardly extending shelf near the guide tool bottom opening, the shelf being sized and shaped so as to be cooperatively rotatably engage the bone screw second attachment structure.   
     
     
         59 . The guide tool according to  claim 58 , wherein:
 a) the bone screw second attachment structure is a partially circumferential groove sized and shaped to rotatably receive the shelf therein.