Section on neurosurgery. (Abstracts of Scientific Posters).

N1-E. LAG SCREW FIXATION OF AN ACUTE HANGMAN'S FRACTURE: CASE ILLUSTRATION. Adam Kremer, MD, John Song, MD, and Peter Konrad, MD, PhD. Vanderbilt University, Nashville, TN.

A 33-year-old, morbidly obese woman presented after an unrestrained, rollover motor vehicle crash in which she sustained multiple injuries. Physical examination revealed no sensorimotor deficits. Neuroimaging demonstrated an asymmetric fracture of the axis, involving the right pars interarticularis and left postero-inferior corner of the body of C2. The displacement of the posterior arch could not be reduced by traction. We opted to perform direct reduction and fixation via a posterior approach using lag screws, similar to the technique described by Borne et al. The superior margin of the lamina of C2 was used as the starting point for screw insertion; direct visualization of the superomedial surface of the isthmus and pedicle, Viewpoint frameless stereotaxy, and lateral fluoroscopy provided the screw trajectory and depth of insertion. Postoperative CT and dynamic radiographs show complete reduction, no instability, and accurate screw placement. The patient remained neurologically intact. She was discharged i n a cervical collar. After 10 weeks, the collar was removed. Dynamic radiographs one year after surgery show fusion of the axis fracture and preservation of physiologic movement at Cl-2 and C2-3. This procedure allows direct reduction and compression of fracture fragments, immediate stabilization, and avoidance of halo immobilization. Rotation at C1-2 is unaffected.