Closure system for spinal fixation instrumentation

A closure system for fixing a spinal fixation element to a spinal fixation element receiving body comprising:

• a low profile outer locking nut for engaging an outer surface of the spinal fixation element receiving body having:
• opposed proximal and distal ends;
• a generally cylindrical, low profile outer surface;
• an inner surface defining an inner bore;
• a spinal fixation element closure surface provided on the distal end;
• and
• an engagement element formed on the inner surface adjacent the distal end for engaging an outer portion of the spinal fixation element receiving body so as to close the spinal fixation element to the spinal fixation element receiving body upon tightening of the engagement element;
• and
• a driving element formed at the proximal end within a periphery defined by the low profile outer surface, the driving element configured to receive a driving tool to tighten the engagement element;
• and
• an inner set screw for engaging an inner surface of a spinal fixation element having
• a body having an outer surface, a proximal end and a distal end;
• a spinal fixation element closure surface provided on the distal end;
• an engagement element formed on the outer surface for engaging an inner portion of the spinal fixation element receiving body so as to close the spinal fixation element to the spinal fixation element receiving body upon tightening of the engagement element;
• and
• a fastening element formed on the proximal end;
• wherein when the outer locking nut is engaged to an outer portion of the spinal fixation element receiving body and the inner set screw is engaged to an inner portion of the spinal fixation element receiving body, the fastening element of the inner set screw is accessible through the inner bore of the outer locking nut so that the outer locking nut and the inner set screw are independently tightenable with respect to the spinal fixation element receiving body.

A system for coupling a spinal fixation element to a patient's spine comprising:

• a spinal fixation element receiving body having a vertebral coupling element disposed on a first end of the body and a spinal fixation element receiving opening formed on a second end of the body, the body including an outer portion adapted to engage an outer locking nut and an inner portion adapted to receive and engage an inner set screw;
• a low profile outer locking nut for engaging an outer surface of the spinal fixation element receiving body having:
• opposed proximal and distal ends;
• a generally cylindrical, low profile outer surface;
• an inner surface defining an inner bore;
• a spinal fixation element closure surface provided on the distal end;
• and
• an engagement element formed on the inner surface adjacent the distal end for engaging the outer portion of the spinal fixation element receiving body so as to close the spinal fixation element to the spinal fixation element receiving body upon tightening of the engagement element;
• and
• a driving element formed at the proximal end within a periphery defined by the low profile outer surface, the driving element configured to receive a driving tool to tighten the engagement element;
• and
• an inner set screw for engaging an inner surface of a spinal fixation element having
• a body having an outer surface, a proximal end and a distal end;
• a spinal fixation element closure surface provided on the distal end;
• an engagement element formed on the outer surface for engaging the inner portion of the spinal fixation element receiving body so as to close the spinal fixation element to the spinal fixation element receiving body upon tightening of the engagement element;
• and
• a fastening element formed on the proximal end;
• wherein when the outer locking nut is engaged to an outer portion of the spinal fixation element receiving body and the inner set screw is engaged to an inner portion of the spinal fixation element receiving body, the fastening element of the inner set screw is accessible through the inner bore of the outer locking nut so that the outer locking nut and the inner set screw are independently tightenable with respect to the spinal fixation element receiving body.