• Progression of Cobb angle to greater than 50 degrees (proxy for surgical indication) [ Time Frame: Measured throughout study ] [ Designated as safety issue: No ]
  
• Cessation of skeletal growth [ Time Frame: Measured throughout study ] [ Designated as safety issue: No ]
  

• Clinical measures [ Time Frame: Measured every 6 months ] [ Designated as safety issue: No ]
  
• Radiographic measures [ Time Frame: Measured every 6 months ] [ Designated as safety issue: No ]
  
• Psychosocial measures [ Time Frame: Measured every 6 months ] [ Designated as safety issue: Yes ]
  

AIS is characterized by a lateral curvature of the spine greater than 10 degrees plus rotation of the spinal vertebrae. AIS is found in adolescents between the age of 10 and time of skeletal maturity. Progression of a spinal curve to 50 degrees suggests a high risk for continued curve progression throughout adulthood and usually indicates the need for spinal fusion surgery. Only about 10 percent of adolescents with AIS end up having curves that progress and require surgical intervention. While certain risk factors for curve progression have been identified, there is no reliable way of estimating the likelihood of needing surgery. Bracing is currently the standard of care for treating AIS. However, the effectiveness of bracing remains unclear, and it is unknown which adolescents in particular may benefit from bracing. Therefore, adolescents undergo bracing without knowing their likelihood of avoiding surgery. The purpose of this study is to compare the risk of curve progression in adolescents with AIS who wear a brace versus those who do not and to determine whether there are reliable factors that can predict the usefulness of bracing for a particular individual with AIS. The study will also evaluate the best dosing and duration schedule and how bracing affects quality of life, functioning, and psychosocial adjustment among participants.

Participation in this study will last until a participant reaches skeletal maturity or their spinal curve progresses to 50 degrees, after which usual care will continue. Participants will be randomly assigned to wear a thoracolumbosacral orthoses brace or not wear a brace. Study visits will occur every 6 months at an orthopaedic surgeon's office and will include x-rays, a clinical exam, and questionnaires. Participants assigned to braces will be instructed to wear the brace at least 18 hours per day. Monitors placed in the brace will be used to determine the actual wear time by each participant.