Duration of Follow-up: Patients will be clinically followed post-surgery throughout the course of the patient's treatment. Follow-up appointments will be scheduled at 1, 6, and 12 months post-surgery and every year thereafter until 5 years after the index procedure, then every 2 years until the final planned procedure, or the completion or spinal growth (typically about 2 years after menarche in girls, or the equivalent in boys), whichever occurs first. Other patient visits may occur as deemed necessary.