The Influence of How Much a Scoliosis Orthosis is Worn and Its Ability to Prevent Curve Progression in Adolescent Idiopathic Scoliosis

Purpose: To determine the relationship between how much a scoliosis orthosis is worn for adolescent idiopathic scoliosis (AIS) and its ability to prevent curve progression.

Methods: From July of 1998 to July of 2000, 126 consecutively treated, skeletally immature patients from a single institution wearing a Boston brace for curves from 25 to 48 degrees due to AIS, with no prior treatment, were prospectively reviewed. Patients were randomly selected for either 23 or 16 hours of recommended wear per day. 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 99%. Of the 126 subjects enrolled into the study, 18 were lost to follow up, 3 went to surgery without demonstrating curve progression, and 3 are still wearing an orthosis. Thus, this review reflects our findings of 102 patients who completed brace treatment either due to reaching skeletal maturity or requiring surgical correction. To better identify those patients most likely to experience curve progression, the 86 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 86 Risser 0 or 1 patients in this review, the amount of time in which the orthosis was worn significantly influenced (p=0.002) the likelihood of an excellent outcome (Fig. 1).For the 16 patients that were Risser 2 or higher at brace prescription, the amount the orthosis was worn had no significant effect on outcome (68% excellent results).

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.