Predictors of Surgical Outcome in Cervical Spondylotic Myelopathy

STUDY DESIGN: Prospective study. OBJECTIVE: To determine whether magnetic resonance imaging and clinical and demographic findings in patients with cervical spondylotic myelopathy (CSM) were independently associated with baseline functional scores and whether these were also predictive of postoperative functional outcomes. SUMMARY OF BACKGROUND DATA: There are considerable limitations in current literature that prevent making formal recommendations regarding the use of clinical and radiological prognostic factors in patients with CSM. METHODS: This prospective study included 65 consecutive patients with CSM treated in a tertiary referral center. The modified Japanese Orthopaedic Association (mJOA) scale was used to quantify disability at admission and at 12-month follow-up. Age, sex, duration of symptoms, severity of myelopathy, spinal column alignment, surgical technique, levels of compression, anteroposterior diameter and transverse area at the site of maximal cord compression, and magnetic resonance imaging signal intensity changes were assessed. Data were analyzed using Spearman rank correlation test, analysis of variance, Mann-Whitney U test, and stepwise multivariate regression. RESULTS: Higher baseline mJOA scores were associated with younger age (P = 0.0002), shorter duration of symptoms (P = 0.03), and greater transverse area (P = 0.02). Better recovery ratio was associated with younger age (P = 0.005) and higher baseline mJOA score (P = 0.003). Greater changes in mJOA score were associated with higher baseline mJOA score (P < 0.0001). Using multivariate analysis, the functional outcomes after surgery were best predicted by baseline mJOA score and age of patient. CONCLUSION: Age and baseline mJOA scores were highly predictive of outcome for patients undergoing surgical treatment of CSM. The degree of spinal cord compression and patterns of signal intensity changes on T1/T2 weighted images were not independently predictive of outcome, but it was found to correlate with the functional status at the time of presentation and age of the patient. The duration of symptoms correlated well with preoperative functional status but did not seem to affect the postoperative outcome.