Curve progression after long-term brace treatment in adolescent idiopathic scoliosis: comparative results between over and under 30 Cobb degrees - SOSORT 2017 award winner.

Background: The factors influencing curve behavior following bracing are incompletely understood and there is no agreement if scoliotic curves stop progressing with skeletal maturity. The aim of this study was to evaluate the loss of the scoliotic curve correction in patients treated with bracing during adolescence and to compare patient outcomes of under and over 30 Cobb degrees, 10 years after brace removal.

Methods: We reviewed 93 (87 female) of 200 and nine patients with adolescent idiopathic scoliosis (AIS) who were treated with the Lyon or PASB brace at a mean of 15 years (range 10-35). All patients answered a simple questionnaire (including work status, pregnancy, and pain) and underwent clinical and radiological examination. The population was divided into two groups based on Cobb degrees (< 30° and > 30°). Statistical analysis was performed to test the efficacy of our hypothesis.

Results: The patients underwent a long-term follow-up at a mean age of 184.1 months (±72.60) after brace removal. The pre-brace scoliotic mean curve was 32.28° (± 9.4°); after treatment, the mean was 19.35° and increased to a minimum of 22.12° in the 10 years following brace removal. However, there was no significant difference in the mean Cobb angle between the end of weaning and long term follow-up period ( p  = 0.105). The curve angle of patients who were treated with a brace from the beginning was reduced by 13° during the treatment, but the curve size lost 3° at the follow-up period.The groups over 30° showed a pre-brace scoliotic mean curve of 41.15°; at the end of weaning, the mean curve angle was 25.85° and increased to a mean of 29.73° at follow-up; instead, the groups measuring ≤ 30° showed a pre-brace scoliotic mean curve of 25.58°; at the end of weaning, it was reduced to a mean of 14.24° and it increased to 16.38° at follow-up.There was no significant difference in the mean progression of curve magnitude between the ≤ 30° and > 30° groups at the long-term follow-up.

Conclusions: Scoliotic curves did not deteriorate beyond their original curve size after bracing in both groups at the 15-year follow-ups. These results are in contrast with the history of this pathology that normally shows a progressive and lowly increment of the curve at skeletal maturity. Bracing is an effective treatment method characterized by positive long-term outcomes, including for patients demonstrating moderate curves.