FOOT DYSTONIA AND LUMBAR CANAL STENOSIS

We describe a patient who developed involuntary, painless, dystonic co ntraction of the toes of the right foot on standing or walking. The de velopment of this abnormal movement had been preceded by sensory distu rbance on the soles of both feet, triggered by dorsiflexion of the fee t. Examination showed that weight bearing on the right foot and walkin g brought on clawing of the toes of the right foot, which was relieved within seconds of taking pressure off the right foot. There was senso ry and reflex evidence of bilateral S1 root disturbance confirmed by e lectrophysiology. Magnetic resonance imaging of the lumbar spine showe d marked stenosis of the lumbar canal with compression of the L5 and S 1 nerve roots bilaterally. Tile patient underwent a lumbar laminectomy with nerve root exit foramina decompression, which abolished the foot dystonia and has considerably improved the sensory disturbance. This case demonstrates that lumbar canal stenosis and/or nerve root compres sion, may be responsible for foot dystonia. Amelioration of the abnorm al movement by surgical decompression argues strongly in favour of thi s hypothesis.