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 . A receiver for a bone anchor and comprising:
 a) a pair of laterally spaced upstanding arms having external surfaces extending from a front side to a back side of the receiver and respective upper surfaces, the arms forming a rod-receiving channel therebetween; and   b) at least one arm having a laterally opening slot formed on a respective external surface and located near the respective upper surface, the slot being sized and shaped to extending radially, circumferentially, and horizontally with respect to the respective external surface, the slot extending to one of the front and back sides of the receiver, the slot having an abutment surface.   
     
     
         48 . A guide tool assembly for implanting a spinal rod in a bone anchor, the tool assembly comprising:
 a) a first tool having an overall length and a lower end snapped onto the bone anchor, said first tool having a central opening extending the entire overall length, and a channel opening radially outward along a lower length of said first tool, so as to form a pass-through passageway for receiving the rod therein; and   b) a second tool configured to push the rod down into the bone anchor.   
     
     
         49 . A guide tool assembly for use with a spinal implant bone anchor and an associated rod, the guide tool assembly comprising:
 a) an elongate body having an overall length and a longitudinal axis with a central opening along the overall length of the elongate body, the elongate body having an outer surface and a channel with a lateral opening extending through the outer surface and along a portion of the length of the elongate body upwardly from a bottom of the body, the channel and the channel opening being sized and shaped for receiving the rod;   b) an opposed spinal implant bone anchor engaging structure near the bottom of the body engaging a bone anchor head; and   c) an elongate rod pushing member having an overall length; wherein   d) the guide tool assembly configured to insert the bone anchor, to manipulate the head of the bone anchor, to insert the rod, to guide the rod to the bone anchor head, and to reduce the rod down into the head by pushing the rod pushing member down on the rod; and wherein   e) the assembly configured to be removable from the bone anchor after the rod has been secured to the head of the bone anchor.   
     
     
         50 . The guide tool assembly of  claim 49 , wherein
 a) the opposed spinal implant bone anchor engaging structure is flexible.   
     
     
         51 . The guide tool assembly of  claim 49 , including
 a) a screw driver to insert the bone anchor.   
     
     
         52 . A guide tool assembly for use with a spinal implant bone screw and an associated rod, the guide tool assembly comprising:
 a) an elongate body having a central opening along an overall length thereof, the body having an outer surface and a channel with a lateral opening extending through the outer surface and along at least a portion of the overall length of the body upwardly from a bottom of the body, the channel and the channel opening being sized and shaped for receiving the rod;   b) an opposed spinal implant engaging structure near the bottom of the body and configured to flexibly engage a head of the bone screw; and   c) a second elongate member having an overall length and being translationally disposed with respect to at least a portion of the flexible engaging structure and configured to cooperate with the guide tool assembly to insert the rod into the bone screw head.   
     
     
         53 . The guide tool assembly of  claim 52 , wherein
 a) at least a portion of the elongate body outer surface is threaded.   
     
     
         54 . In a bone anchor having a head with first and second opposed arms defining a channel therebetween and a shank pivotable with respect to the head, the improvement wherein:
 a) the shank is cannulated; and   b) the first arm has an outward facing slot, the slot formed in and extending horizontally and circumferentially about a periphery of the first arm, the slot remaining open and uncovered when a closure is in the channel.