[A case of achondroplasia showing diffuse spinal canal stenosis]

A rare case of achondroplasia showing diffuse spinal canal stenosis is presented. A 39-year-old woman was admitted to our hospital because of numbness of lower extremities and intermittent claudication. The patient's height was 121cm and she had the typical clinical features of an achondroplastic dwarf. Neurological examination revealed spastic paraparesis, and sensory impairment below the level of T11 in the left side and L1 in the right. A plain X-ray feature of the spine showed spinal canal stenosis. The interpedicular distances were short in all vertebrae, and especially more prominent in the caudal lumbar region. The sacrum laid horizontally and the sacral angle was narrower than normal case. Myelography and computed tomographic myelography demonstrated severe stenosis of the subarachnoid space at the level of T9-11. Laminectomy was performed from the inferior half of T9 to T11. The yellow ligaments were prominently hypertrophic and these were removed as far as possible. Postoperatively, the weakness of the lower extremities was improved immediately, but numbness remained. Five months after the operation, she suffered from urinary dysfunction, so further laminectomy from T12 to L5 was performed. Also in this operation, hypertrophic yellow ligament was pathognomonic. Following this operation the patient had a good recovery course and returned to work.