Patterns and progression in congenital scoliosis.

Sixty cases of congenital scoliosis over a 13-year period were studied. The female:male ratio was 1.4:1. The deformity usually presented itself first either at 2 or 8-13 years of age. A positive family history was present in five cases, and parental consanguinity was observed in 40% of patients. Five patterns of deformity were recognized. Hemivertebra was the most common type, and unilateral unsegmented bar with contralateral hemivertebra was the most severe and most progressive pattern of deformity. Thoracic curves were more prevalent while larger curves were more commonly seen in the thoracolumbar area. The curves measured >40 degrees in 70% of the patients who had reached maturity. The curve progression index was 9 degrees for unilateral unsegmented bar with contralateral hemivertebra, and 6 degrees without contralateral hemivertebra. This index was 1.5 degrees for hemivertebra and complex type of deformity, and 0.5 degrees for block vertebra. Unbalanced fully segmented hemivertebra was next after the two types of unsegmented bars in terms of potential for progression. Presence of fused ribs on concave side of lower thoracic curves increased the rate of curve progression. Spinal dysraphism, diagnosed in 20% of cases, was the most commonly associated anomaly.