1. 1Department of Neurological Surgery, Cedars-Sinai Medical Center, Los Angeles;
2. 2Department of Neurological Surgery, Northwestern Memorial Hospital, Chicago, Illinois;
3. 3Howell Allen Clinic, Nashville, Tennessee;
4. 4German Scoliosis Center, Bad Wildungen, Hesse, Germany and
5. 5National Naval Medical Center, Bethesda, Maryland
6. 6Department of Neurological Surgery, University of California, San Francisco, California;