Correlation of scoliotic curvature with Z-score bone mineral density and body mass index in patients with osteogenesis imperfecta

Abstract

Study design: A cross-sectional radiographic and clinical study of patients with osteogenesis imperfecta (OI).

Objective: To determine demographic, anthropometric, and radiographic parameters that correlate with development of scoliosis in patients with OI.

Summary of background data: Despite the relatively high prevalence of scoliosis in patients with OI and its clinical significance, little is known about demographic and anthropometric parameters that correlate with the development of scoliosis.

Methods: Clinical records and spinal radiographs of 19 OI patients were reviewed. There were 5 male and 14 female patients with an average age of 14.2 years (range, 4-20 years). Seven patients were Sillence Type I and 12 patients were Type III. The Cobb angle of scoliosis was analyzed for correlations with age, body mass index (BMI), physical capability, leg-length discrepancy, Z-score bone mineral density (BMD) in the lumbar spine, thoracic kyphosis angle, and lumbar lordosis angle by using Pearson's correlation method. A probability of less than 0.05 was considered statistically significant.

Results: The average Cobb angle of scoliosis was 25.2 degrees (range, 5 degrees-108 degrees) including 6 patients with an angle of > or = 30 degrees. Five of these 6 patients were Sillence Type III. Statistical analysis showed a significant positive correlation between the extent of scoliosis and BMI, as well as leg-length discrepancy. There was an inverse correlation between the extent of scoliotic curvature and the Z-score BMD as well as the thoracic kyphosis angle.

Conclusion: The correlation of scoliosis with the Z-score BMD and BMI supports the pathology of scoliosis based on vertebral fragility. Proper management of BMD and BMI may have therapeutic value in delaying the progression of scoliosis in patients with osteogenesis imperfecta.