The influence of how much a scoliosis orthosis is worn and its ability to prevent curve

Donald E. Katz, CO and Richard H. Browne, PhD

Introduction: A considerable amount of literature suggests that orthotic treatment for adolescent idiopathic scoliosis (AIS) can prevent progression of a curve that would otherwise worsen if left untreated. Among a number of variables in orthotic treatment, the amount of time in which an orthosis needs to be worn to be effective is not well understood. Most studies on the efficacy of orthotic treatment for adolescent idiopathic scoliosis have no measure of compliance with wear schedules other than patient or family reports. The true effectiveness of bracing cannot be determined without accurately documenting actual wear. Thus, the purpose of this prospective study was to objectively measure the wear patterns of those with AIS prescribed to wear an orthosis, and to study the impact of actual wear on treatment outcome.

Methods: From July of 1998 to July of 2000, 152 consecutively treated, skeletally immature patients from a single institution wearing either a Boston or Charleston brace for curves from 25 to 48 degrees due to AIS, with no prior treatment, were prospectively reviewed. Those prescribed a Boston brace were randomly selected for either 23 or 16 hours of recommended wear per day, while those prescribed a Charleston brace were asked to wear it 8 hours at night. The amount of time in which each orthosis was worn was documented utilizing a temperature data logger and algorithm to specify dates and times of actual wear throughout treatment. In a separate review, this method of documenting brace wear was shown to accurately estimate the specific times in which a scoliosis orthosis was worn by a factor of greater than 96%.

Of the 152 subjects enrolled (132 Boston brace; 20 Charleston brace), 25 patients (24 Boston; 1 Charleston) were lost to follow up, 2 patients were excluded due to insufficient data for review, 3 patients were excluded because surgery was undertaken despite no evidence of curve progression, 5 patients were excluded due to breaches in study protocol, and 3 patients were still on-going treatment at the time of this review. Thus, a total of 114 patients (98 Boston brace wearers; 16 Charleston brace wearers) serve as the population for this review. To better identify those patients in a Boston brace most likely to experience curve progression, the 82 patients that were Risser 0 or 1 at brace prescription were analyzed separately from the 16 patients that were Risser 2 or higher.

An Excellent outcome resulted when either curve correction or progression of 5 degrees or less occurred; a Fair outcome reflected those that demonstrated curve progression greater than 5 degrees but surgical stabilization was not recommended; a Failed outcome reflected those who demonstrated curve progression of >5 degrees and surgical stabilization was recommended. Results: For the 82 Risser 0 or 1 patients treated with a Boston brace, the amount of time in which the orthosis was worn significantly influenced (p=0.008) the likelihood of an excellent outcome (Fig. 1).

Results: For the 82 Risser 0 or 1 patients treated with a Boston brace, the amount of time in which the orthosis was worn significantly influenced (p=0.008) the likelihood of an excellent outcome (Fig. 1).

For the 16 Boston brace patients that were Risser 2 or higher at prescription, the amount the orthosis was worn had no significant effect on outcome (68% excellent results). In the 16 patients treated with a Charleston brace, results were similar but statistical significance was not achieved due to a small sample size.

Conclusion: A significant positive correlation exists between the amount a Boston brace is worn and its ability to prevent curve progression in patients with AIS. No such correlation exists in those whom are more mature (Risser 2 or greater) at the time of brace prescription, as these patients tend to do well without regard to how much an orthosis is worn.