Does developmental canal stenosis influence surgical results of bilateral open-door laminoplasty for cervical spondylotic myelopathy?

OBJECT: The purpose of this study was to investigate the prevalence of developmental canal stenosis in patients with cervical spondylotic myelopathy (CSM), and the correlation between surgical results and degree of developmental canal stenosis. METHODS: A total of 112 patients who eventually had surgical treatment for CSM were evaluated. Male patients whose sagittal spinal diameter was < 14 mm and females whose sagittal diameter was < 13 mm even at one level were classified as having developmental canal stenosis. Two groups of patients were used in this study; the "positive" group (57 cases) included patients with developmental canal stenosis preoperatively, whereas the "negative" group (55 cases) excluded such patients. Lateral functional radiographs obtained in patients in the 2 groups were compared for range of motion and clinical results. RESULTS: Developmental canal stenosis was found in 50.9% of all cases. Based on clinical results, there was no significant difference between the 2 groups. CONCLUSIONS: Patients with CSM showed a high incidence of preoperative developmental canal stenosis. However, there were no significant differences in clinical results between patients with and without this disorder. These results indicate that developmental canal stenosis is not a factor that influences surgical results.