1. 1Illinois Neuro-Spine Center, Aurora, Illinois;
2. 2Texas Back Institute, Plano, Texas;
3. 3Spine and Scoliosis Center, Towson, Maryland;
4. 4Buffalo Spine Surgery, Lockport, New York;
5. 5Lennox Hill Hospital, New York, New York; and
6. 6Goldstein and Penenberg Orthopedic Associates, Beverly Hills, California