The symptoms, physical findings, and roentgenograms of sixty patients who underwent cervical discectomy and interbody fusion by the Robinson-Smith technique were reviewed and compared with the patient's condition two to nine years after surgery. On the basis of such a long-term evaluation, these patients were categorized and the findings were utilized to determine the factors that influence the results of surgery. These findings were as follows:

1. Patients with radicular symptoms had a higher rate of improvement than those whose symptoms were non-radicular. A positive correlation was found between satisfactory results and either motor or sensory deficits. This correlation was still greater when both motor and sensory findings were present.

2. Men tended to have much better results from discectomy than did women.

3. Occipital headaches and non-radicular symptoms as the predominant complaints tended to reduce the likelihood of a desirable result although some patients with such complaints were greatly improved.

4. A slight but definite correlation was obtained between the findings on roentgenograms of the cervical spine and the results of surgery. Patients with apparently normal cervical spines tended to have less desirable results than those with osteophyte formation or narrowing of the interspace or both.

5. The value of discography and myelography was not clearly defined by this evaluation. These methods are of secondary importance to the clinical evaluation.

6. Patients with correlating symptoms and signs of root compression had better results from surgery than did those whose treatment resulted in bone fusion, suggesting that the selection of patients for cervical discectomy may be more important than the obtaining of a bone fusion.