RT Journal Article SR Electronic T1 3D-printed brace in the treatment of adolescent idiopathic scoliosis: a study protocol of a prospective randomised controlled trial JF BMJ Open JO BMJ Open FD British Medical Journal Publishing Group SP e038373 DO 10.1136/bmjopen-2020-038373 VO 10 IS 11 A1 Zhang, Youyu A1 Liang, Junyang A1 Xu, Nanfang A1 Zeng, Lin A1 Du, Chaojun A1 Du, Yaoxu A1 Zeng, Yan A1 Yu, Miao A1 Liu, Zhongjun YR 2020 UL http://bmjopen.bmj.com/content/10/11/e038373.abstract AB Introduction Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine. Brace treatment is effective for eligible patients with AIS and the effectiveness is significantly correlated with the average brace-wear time per day. Three-dimensional (3D) printing technology is a recent advancement that offers unique opportunities for biomedical applications, and customisation of scoliosis braces might lead to greater patient satisfaction and improved compliance. We present here the design of a randomised controlled trial on the clinical effectiveness of 3D-printed braces versus thoracolumbosacral orthoses (TLSO) for patients with AIS.Methods and analysis Patients with AIS (age 10–16 years) with Risser sign 0-II, Cobb angle of main curve of 20°−40°, premenarchal or no more than 1-year postmenarchal (for women), and no history of treatment are eligible, unless they are unable to tolerate the treatment or refuse participation. A total of 88 patients will be randomised into either the 3D group or TLSO group on a 1:1 basis. Participants in the 3D group will choose between a 3D-printed brace and TLSO, according to the Zelen’s design of the trial. Primary outcome measures will include the average brace-wear time per day, health-related quality of life and Cobb angle progression of the primary curve. Secondary outcome measures will include immediate in-brace correction of Cobb angle of the primary curve, rate of conversion to surgery and incidence of any adverse events. This study is designed as a single-centre, two-arm, superiority and open-label randomised controlled trial. The sample size is calculated with reference to the preliminary study and based on the sample size calculation formula.Ethics and dissemination This study was approved by the Peking University Third Hospital Medicine Science Research Ethics Committee (No: 2019-017-02). Results of the trial will be submitted for publication in a peer-reviewed journal and as conference presentations.Trial registration number ChiCTR1900027379, pre-results.