Brace treatment versus observation alone for scoliosis associated with Chiari I malformation following posterior fossa decompression: a cohort study of 54 patients.

PURPOSE: To be deemed effective in preventing curve progression, brace treatment should show alteration of the expected natural history. Most of the reported studies on the effect of bracing on the evolution of Chiari malformation-associated scoliosis (CMS) following posterior fossa decompression (PFD) were small series with inconclusive results. The goal of this study was to investigate whether post-PFD brace treatment for CMS produces better outcomes than observation alone.
METHODS: The clinical and radiographic data of 21 patients treated with observation alone (Ob group) and 33 patients receiving brace treatment (Br group) were retrospectively reviewed. Evolution of scoliosis was defined as progression of Cobb angle of the primary curve of >5°, as compared with that at brace initiation.
RESULTS: At the latest follow-up, curve progression occurred in 10 (30 %) of Br group and 13 (62 %) of Ob group (P = .022). Overall, 8 (24 %) patients in the Br group and 9 (43 %) in the Ob group underwent further scoliosis surgery (P = .151). When analyses were restricted to the 27 braced and 17 observed patients who had reached skeletal maturity or undergone spinal fusion surgery, decreased curve progression and surgical rates were also observed in the Br group though not reaching statistical significance. Results of the survival analysis, however, demonstrated a significantly increased survival proportion in the Br group (0.63 versus 0.35, P = .014).
CONCLUSIONS: Compared with observation alone, bracing treatment following PFD in patients with CMS was observed to reduce the rates of curve progression and scoliosis surgery. However, patients and their parents should be informed that almost a third of patients still go on to surgery.