Predictive factors for postoperative motor recovery of proximal upper extremity in patients with degenerative cervical myelopathy: a multicenter prospective study.

STUDY DESIGN: Multicenter prospective study. OBJECTIVE: To clarify the postoperative course and predictive factors for motor recovery of the proximal upper extremity in patients with degenerative cervical myelopathy (DCM). SETTING: Keio University School of Medicine and affiliated hospitals belonging to Keio Spine Research Group (KSRG). METHODS: From a total of 1322 patients undergoing surgery for DCM, 363 patients with preoperative weakness in the deltoid or biceps brachii were included. Patients were divided into two groups based on their status at 2 years postoperatively: P group (persistent weakness; n = 131) and C group (complete recovery; n = 232). Variables including age, sex, medical history, duration of symptoms, surgical procedure, radiographic parameters, Japanese Otrhopaedic Association (JOA) scores, JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), SF-36, and pain scales were compared. RESULTS: P group was significantly older and had higher rates of hypertension, cerebrovascular disease, other musculoskeletal diseases, and prior cervical surgery. Preoperative JOA scores for upper extremity motor function were also significantly lower in P group (p < 0.05). Multivariate logistic regression analysis identified lower preoperative JOA motor scores (OR 3.27), prior cervical surgery (OR 3.29), history of other musculoskeletal diseases (OR 1.77), and history of hypertension (OR 1.64) as significant predictors of poor prognosis (p < 0.05). CONCLUSION: Surgical interventions are effective for motor recovery, with over 60% of patients achieving full strength. However, preoperative motor severity, prior surgery, history of other musculoskeletal diseases, and history of hypertension are key predictors of limited improvement. LEVEL OF EVIDENCE: Level II.