Deformities of the spine in neurofibromatosis. Clinical and radiographic study of 46 cases.

Scoliosis, in particular kyphoscoliosis, is the most frequent bony abnormality in neurofibromatosis (up to 43 per cent). The most usually accepted aetiopathogenesis is a primary mesoblastic defect of the vertebrae, though other hypotheses exist. Hereditary factors have been shown to be present in about half the cases and the spinal deformity is almost always associated with skin changes, and less frequently with nerve or cardiac changes or with elefantiasis. The ages most affected are from four to eleven years, the commonest site is the dorsal spine and the average number of affected vertebrae is 5.5. There are three main radiological characteristics: widening of the spinal canal, widening of the intervertebral foraminae, and a scalloped appearance of the posterior borders of the vertebral bodies. From the point of view of prognisis the scoliosis is markedly progressive and difficult to control, even after bone maturity. In consequence, neurological symptoms frequently arise, usually as late complications.