1. Orthopaedic and Traumatology Department, Institute of Orthopedics “Carlos E. Ottolenghi,” Hospital Italiano de Buenos Aires, Buenos Aires, Argentina;
2. Departments of Orthopaedics and
3. School of Medicine, University of California, Irvine, Orange, California
4. Neurosurgery, University of California, Irvine, Orange, California; and