Congenital kyphosis due to defects of anterior segmentation.

Twenty-seven patients with Type-II congenital kyphosis (failure of anterior vertebral segmentation) all had progression of the kyphosis which varied in magnitude. The average rate of progression was 5 degrees per year. Pain due to compensatory lumbar hyperlordosis (eight patients) and objectionable deformity (fifteen patients) were the most frequent complaints. Unlike patients with Type-I kyphosis (failure of vertebral formation), paraplegia did not occur and associated congenital anomalies were infrequent (three of the twenty-seven patients). Spontaneous ossification of the anterior part of seemingly normal intervertebral discs leading to bar formation and progression of deformity occurred in five patients. A Milwaukee brace had little effect on this fixed kyphotic deformity in the six patients in whom the brace was used. Early recognition and spine fusion are the recommended treatment. Posterior fusion is sufficient in young children with progressive deformity, whereas combined two-stage anterior and posterior fusion with osteotomy of the anterior bar is recommended in children with severe deformity.