1. Department of Orthopaedic Surgery, University of Pittsburgh, 3471 Fifth Avenue, #1010, Pittsburgh, PA 15213.
2. VA Pittsburgh Healthcare System, University Drive C, Pittsburgh, PA 15240.
3. Department of Neurology, University of Pittsburgh, 811 Kaufmann Medical Building, 3471 Fifth Avenue #810, Pittsburgh, PA 15213.
4. Magnetic Resonance Research Center, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15213.