Study design: A retrospective single-center study.
Objective: To investigate the prevalence of symptoms before and after surgery in a large series of patients with cervical spondylotic myelopathy (CSM).
Summary of background data: No study has elucidated the epidemiological data regarding the prevalence of pre- and postoperative symptoms in patients with CSM.
Methods: Five hundred twenty consecutive patients with CSM (331 male and 189 female; mean age, 62.2 yr) treated by laminoplasty were enrolled. The average follow-up period was 33.3 months. Severity of myelopathy was evaluated according to a scoring system proposed by the Japanese Orthopedic Association for CSM, and prevalence was determined by the presence or absence of a full Japanese Orthopedic Association score for each function. The persistence rate (%) (postoperative prevalence/preoperative prevalence × 100) of each function impairment was also assessed after surgery.
Results: The preoperative prevalence of motor function impairment in the upper and lower extremities was 77.7% and 80.4%, respectively, whereas that of sensory function impairment in the upper and lower extremities and trunk was 88.6%, 56.5%, and 48.3%, respectively. The preoperative prevalence of urinary bladder function impairment was 41.2%. The persistence rate of motor function impairment in the upper and lower extremities was 52.7% and 71.5%, respectively, whereas that of sensory function impairment in the upper and lower extremities and trunk was 72.0%, 56.8%, and 61.4%, respectively. The persistence rate of urinary bladder function impairment was 49.1%.
Conclusion: The preoperative prevalence of motor function impairment in the upper and lower extremities and that of sensory function impairment in the upper extremity is higher than that of other function impairments, and impairments in lower extremity motor function and upper extremity sensory function often persist after surgery. These findings provide baseline data that may allow clinicians to accurately assess preoperative impairment and postoperative outcomes in patients with CSM.