Patent ID: 8617210

Claim:
A system comprising: a percutaneous access device comprising an inner member having a proximal end, a distal end, and a lumen extending between the proximal end and the distal end; an outer member disposed about at least a portion of the inner member, the outer member having a proximal end, a distal end, and a lumen extending between the proximal end and the distal end; the outer member being sized to span from at least a skin incision in a patient to a predetermined site proximate the spine of the patient, and an adjustment mechanism connecting the inner member to the outer member and being operable to axially adjust the inner member relative to the outer member along the longitudinal axis of the outer member between a proximal position and a distal position; and a bone anchor assembly comprising: a bone anchor having a proximal head and a distal bone engaging portion; and a receiving member coupled to the bone anchor, the receiving member having a proximal end, a distal end and a recess for receiving a spinal fixation element, the receiving member having a substantially U-shaped cross-section defined by two legs separated by the recess, each leg being free at the proximal end of the receiving member, an exterior surface of a proximal end of a first one of the legs including a first groove and an exterior surface of a proximal end of a second one of the legs including a second groove, the first groove having a proximal surface and a distal surface opposite the proximal surface and the second groove having a proximal surface and a distal surface opposite the proximal surface, the proximal surface of the first groove and the distal surface of the first groove each are angled distally toward the exterior surface of the first leg and each are oriented at an angle greater than 0 degrees relative to an orthogonal line that is oriented perpendicular to a longitudinal axis of the receiving member, the proximal surface of the second groove and the distal surface of the second groove each are angled distally toward the exterior surface of the second leg and each are oriented at an angle greater than 0 degrees relative to an orthogonal line that is oriented perpendicular to the longitudinal axis of the receiving member, wherein the distal end of the outer member is adapted to releasably engage the the first groove and the second groove and wherein, when the distal end of the outer member is engaged to the receiver member, the inner member is adjustable by the adjustment mechanism to the distal position and into to contact with the proximal end of the receiving member.