Role of Body Cast Application for Scoliosis Associated With Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare genetic syndrome, with a prevalence of infantile scoliosis of ~23%. These curves are likely related to severe hypotonia. Approximately 15% of children with PWS will need surgical intervention for their scoliosis. The purpose of this study was to evaluate the effectiveness of curing or controlling moderate and severe infantile scoliosis curves in children with PWS.

This single institution, retrospective study of patients with PWS and infantile scoliosis reviewed 34 consecutive children with >24 months follow-up from initiation of serial spinal casting. Cobb angle comparison measurements of radiographs taken precasting, during treatment, and at follow-up were performed. Rib-vertebral angle difference, Nash-Moe rotation, and space available for lung measurements were followed. Outcomes were stratified as "Cured," "Braced," and "Surgery."

Average age for first cast for the entire study was 32 months (range, 14 to 64), undergoing 8 casts (range, 3 to 18) over 25 months (range, 9 to 57) for an initial curve of 54 degrees (range, 27 to 106 degrees), which improved to 27 degrees (range, 11 to 78 degrees). In total, 12 patients (35%) were in the Cured group, following 6 casts over 17 months, with an initial curve of 44±14 degrees improving to 17±5 degrees at the end of treatment, and 20±18 degrees at 68-month follow-up. In total, 18 patients were in the Braced group, with curves initially improving from 55±14 degrees to 35±14 degrees, but at 47±20 degrees at 51-month follow-up. Four patients needed surgery, with initial curves 85 degrees (range, 54 to 106 degrees), but surgery could be postponed 56 months (range, 40 to 73) by casting. Rib-vertebral angle difference was not prognostic.

Serial spinal casting is effective in for treating infantile scoliosis in children with PWS. One third of patients had their curve resolved, at least temporarily, where they were braced and cast free. The others were able to delay surgery for a number of years. Initial curves <50 degrees in children <3 years of age seem to have the best prognosis.

Level IV.