Treatment of cervical disc disease using Cloward's technique. III. Evaluation of cervical spondylotic myelopathy in 138 cases.

Among 1,106 patients with cervical disc disease treated with Cloward's operation over a fifteen-year period, 138 patients had symptoms and signs of spinal cord involvement. The median symptom duration was one year. Nearly all had gait disturbances, 63% had spasticity of the lower extremities and 11% had various degrees of tetraplegia. Three months after surgery 78% of the patients were found to have some symptoms, but only 5% had no symptoms at all. At the time of the questionnaire (average 7.7 years postoperatively) 46% of the patients stated they were still affected by the operation. The duration of preoperative symptoms was of significance to the outcome, but age, sex, and severity of myelopathy were not. It was demonstrated that patients with medullary involvement had a higher annual mortality rate than patients with radicular symptoms, and that this rate depended on the severity of the spinal cord symptoms.