Purpose of the study: Determine the prevalence and course of spinal deformations in Willi-Prader syndrome and assess the effect of treatment with growth hormone. Analyze outcome after conservative and surgical treatments.

Material and methods: We reviewed the files of 51 patients with Willi-Prader syndrome proven genetically. Spinal deformations were classed according to the SRS system. Body mass index (BMI) was determined and correlated with age and administration of growth hormone. Statistical analysis used the coefficient of correlation and the chi-square test to search for correlations between qualitative variables.

Results: There were 37 girls and 24 boys, mean age at last follow-up 10.7±6.7 years. The prevalence of scoliosis was 52% and varied according to genotype.

The prevalence of scoliosis deformations was higher in patients aged over ten years (p< 0.01). The prevalence of scoliosis was greater in female patients. Patients with BMI< 25 had a significantly lower risk of scoliosis. Treatment with growth hormone was associated with a significant decrease in risk of scoliosis. Among scoliosis patients, ten had a main curvature < 15° and were monitored. Eleven had a curvature > 15° (31±11°) and were treated with a corset. Five had a curvature > 50° and trunk imbalance and were treated surgically. Four of these patients developed serious complications.

Discussion: Scoliosis deformation is frequent in Willi-Prader syndrome. Weight control is very important and BMI should be maintained below 25 to limit the risk of scoliosis. Treatment with growth hormone helps limit BMI and thus the risk of scoliosis. For major deformations, surgical treatment is indicated but at the risk of serious postoperative complications.