Idiopathic scoliosis is the most common spinal deformity in children and adolescents with an estimated prevalence of 3%. About one tenth of the children with scoliosis develop a deformity that requires treatment with brace or surgery with the current treatment protocol. When brace treatment for scoliosis is indicated, standard treatment consists of bracing 20 hours or more per day. Outcomes of brace treatment depend to a large extent on wearing time and since many adolescents feel uncomfortable in the brace, it is of importance to combine efficacy and comfortability of the brace.

Bracing with a rigid TLSO is gold-standard treatment in terms of halting progression of idiopathic scoliosis in skeletally immature adolescents and children. The treatment is cumbersome and demanding for adolescents during a vulnerable stage in life, and may be associated with poor compliance. Furthermore, the treatment lasts in many cases for several years and has shown to have a negative psychological effect for patients. Since time in brace is of utmost importance for best possible outcome, the braces need to be tolerated by the patients. As of today, 3D designed braces have received much attention and are thought to increase comfortability and ultimately increase wearing time, leading to better outcomes.

In a multicenter randomized controlled trial, we seek to compare standard Boston brace to a newly developed 3D designed Boston brace. Skeletally immature patients with idiopathic scoliosis will be randomized to receive either standard Boston brace or Boston 3D brace. All patients will be encouraged to be physically active for 60 minutes per day. Patients, outcome assessors and clinician in charge during follow-ups will be blinded for the type of brace the patients are being treated with. Thermal sensors will be installed in all braces to monitor compliance. Outcome include change in curve severity, quality of life and surgical rates. Patients will be evaluated with clinical and radiological follow-ups every six months until skeletal maturity and thereafter at 2, 5 and 10 years. Curve progression will not lead to change of brace. A total of 85 individuals are required in each group based on the hypothesis of a 2% failure rate in the 3D-brace group and 15% in the standard brace group with 5% significance level and 80% power and consideration for dropout of up to 20%.

For individuals who are not willing to be randomized and participate in the study, standard Boston brace will be offered and these individuals will serve as an observational group with similar follow-ups and will be asked to answer same survey as the study populations will do.

Inclusion Criteria:

• Cobb 25-40 degrees
• Skeletally immature, Sanders score of 6 or less and Risser 2 or less.
• Menarche status maximum one year in females
• Aged 9-17 years
• No previous brace treatment or surgery for scoliosis
• Apex of the primary curve at T7 or caudal

Exclusion Criteria:

• Non-idiopathic scoliosis (i.e. neuromuscular, syndromic or congenital scoliosis)
• Previous spine surgery

IPD underlying published manuscripts will be accessible for other researchers.

The study protocol will be submitted to a peer-reviewed journal.

The investigators in charge will be responsible for reviewing access requests. Crude data, randomization procedures and intervention details can be shared with other researchers upon request.

Orthotist and research nurse will know what type of brace the participant receives, but will not tell the participant which type he/she has received. Investigators, care providers and outcome assessors will be blinded for type of brace.