A case of cervical myelopathy with developmental canal stenosis at the level of the atlas. A case report.

The craniocervical junction is one of the most common sites of malformations. Only three cases of myelopathy due to hypoplasia of atlas have been reported previously. Among these malformations, the hypoplasia of atlas was first described by Wackenheim in 1974. Although developmental canal stenosis due to the hypoplasia of atlas seems to have a tendency of causing the cervical myelopathy, only three cases of cervical myelopathy due to this condition have been reported previously. A 77-year-old man with severe canal stenosis at the level of the atlas is reported. The clinical manifestations were 20-year history of progressive gait disturbance and paresis of both upper and lower extremities. The spinal cord was markedly compressed at the level of the atlas. The clinical manifestations improved after a resection of posterior arch of the atlas.