Degenerative arthritis of the adjacent spinal joints following anterior cervical spinal fusion : clinico-radiologic and statistical correlations

: On the premise that cervical intersomatic spinal fusion in the treatment of traumatic or spondylolytic myelopathy and post-traumatic instability provokes degenerative arthritis due to functional overloading of the spaces adjacent to the fusion, 37 patients (average age 57, range 25-80) who had undergone spinal fusion by Cloward's technique were subjected to radiographic study and clinical evaluation. The average follow-up was 11.5 years (range 7-16 years). In comparison with a control group of the same age who had not undergone this operation, these patients' C3-C4 and C6-C7 spaces (adjacent to the most commonly fused vertebrae) were smaller by 16.7% and 15.9%, respectively. In spite of the worsening of the radiographic situation, from a clinical standpoint there was a significant improvement in the symptomatology of 86.5% of the patients. Thus the degenerative arthritis is both less evident and, as far as the long-term clinical outcome is concerned, less influential than could be expected. This finding is confirmed by the lack of statistical correlation between the clinical results and the radiographic evidence.