"Cured" patients with early-onset idiopathic scoliosis after serial casting are at risk of recurrence at intermediate follow-up.

Abstract

Serial casting limits curve progression while preserving spinal growth, delaying or even eliminating the need for surgery. Some patients with EOIS can be "cured" with curve reduction under 15°. However, no long-term studies have defined whether "cured" patients maintain small curves or if they are at risk of progression. We examined if casting patients remained "cured" following treatment. We identified 40 EOIS patients who were treated with serial casting, achieved curves under 15° and had minimum 2 years of follow-up after completing the treatment. Failure was defined as an increase > 6° resulting in a curve magnitude > 15° at any point during follow-up, requiring cast/brace treatment after cessation of initial cast/brace, or undergoing surgery. Average curve magnitude at the time of cure was 11.1°. Kaplan-Meier survival analysis was used to identify failure rates over time. 10 patients (25.0%) met criteria for failure. Mean time from cure to last follow-up was 4.3 years. 3 patients (7.5%) completed bracing and were later re-braced while 2 (5.0%) required surgery. Mean curve magnitude of "failed" patients was 27.4° with an average increase of 15.6°. At 5.1 years, probability of successful treatment is 64.2%. For "failed" patients, median time to failure was 2.4 years. Successful patients were braced for median 1.4 years, while "failed" patients had a median of 1 year. While EOIS patients may be "cured" with serial casting, this may not be sustained. The percentage of "failures" likely will increase with longer follow-up through skeletal maturity, and patients must be closely monitored after concluding casting/bracing.