Atlantoaxial dislocation associated with neurofibromatosis. Report of three cases.

Atlantoaxial dislocation was found in three patients with neurofibromatosis. Roentgenographic findings included marked reduction of sagittal diameter at the C-1 vertebral level, and cervical spine abnormalities associated with mesodermal dysplasia, such as posterior scalloping of the cervical spinal bodies with dural ectasia and vertebral body deformity (vertebral body dysplasia). Although the relationship of the atlas and axis did not change with neck position, all three patients had progressive neurological deficits and were treated by decompressive surgery combined with fusion. The pathogenesis of atlantoaxial dislocation associated with neurofibromatosis is discussed.