Brace treatment of Idiopathic Scoliosis is effective for a curve over 40 degrees, but is the evaluation of Cobb angle the only parameter for the indication of treatment?

Background: The recent literature showed positive results for bracing of patients with idiopathic scoliosis above 45° who refused surgery. However, no one has investigated whether other parameters can affect the results.
Aim: The aim of this study was to evaluate the effectiveness of bracing in idiopathic scoliosis with curves above 40° and to verify the mechanical and biological parameters which go beyond the simple bend value expressed in Cobb degrees.
Design: This is an observational controlled cohort study nested in a prospective clinical on-going database including 1,238 patients with idiopathic scoliosis.
Setting: Inpatients and outpatients in Rome.
Population: The study enrolled 160 patients with idiopathic scoliosis with curves above 40°.
Methods: This is a prospective study based on an ongoing database including 1,238 patients with idiopathic scoliosis. The patients studied had idiopathic scoliosis with curves of 40° or more, Risser grade 0-4, and had refused any surgical treatment. 160 patients met the inclusion criteria. Of these, 104 patients had a definite outcome, 28 abandoned treatment and 28 are currently under treatment. The minimum duration of follow-up was 24 months. X-rays were used to obtain Cobb degrees and torsion of the apical vertebrae (Perdriolle's method). Three outcomes were distinguished according to SRS-SOSORT criteria: correction, stabilization and progression. To achieve the second aim, we divided the sample into subgroups according to Cobb degrees (<45°; ≥45°), Risser (0-2; 3-4) and rotation (<20; ≥20). Furthermore, logistic regression was applied by Stepwise Regression.
Results: The results of our study showed that in 104 patients with a definite outcome the Cobb mean value was initially 47±5.25 SD and 34.19 ±8.45 SD at follow-up. Perdriolle was initially 20.04±5.53 SD and 16.76±7.04 at follow-up. Overall, 81 patients (78%) obtained a curve correction, and stabilization was achieved in 14 cases (13%). Nine patients experienced curve progression (9%), 16 patients were recommended for surgery because the curve at follow up was over 45°. The analysis of subgroups shows that with Cobb <45° at baseline, the average reduction was 11.46° Cobb, while in cases with Cobb ≥45 at baseline, the mean correction was 13.74° Cobb. In subgroups with Perdriolle <20° at baseline, the average reduction was 16.02° Cobb, while in cases with Perdriolle ≥20° at baseline, the mean correction was 8.4° Cobb. In subgroups with Risser 0-2 at baseline, the average reduction was 14.7° Cobb, while in cases with Risser 3-4 at baseline, the mean correction was 6.7° Cobb. The logistic regression model shows significance for the initial value of Perdriolle and Risser.
Conclusions: Our results indicate that an adequate conservative treatment must definitely be considered for patients with scoliotic curves who refuse surgery; the results will be better particularly if the rotation is lower than 20 and Risser is between 0-2.
Clinical Rehabilitation Impact: With the simultaneous evaluation of the Cobb angle, the vertebral rotation and the potential vertebral growth, it was possible to predict the final results at the start of treatment.