Correlation and change of quality of life and neurological function outcome for cervical spondylotic myelopathy after surgery

English Keywords:Cervical spondylotic myelopath  Outcome assessment  SF-36  Modified JOA score

English Abstract:

  【Abstract】 Objectives: To investigate the profile of quality of life(QOL) outcome after surgery for cervical spondylotic myelopathy(CSM) and its consistency with neurological function by using a cohort study. Methods: The sample comprised 280 patients who underwent surgical treatment for cervical spondylotic myelopathy in our hospital between February 2008 and May 2013. The mJOA score and SF-36 were used to evaluate the neurologic function, QOL was recorded before surgery, 3 months after surgery, 1 year after surgery and at final follow-up. The profile of health status measures(HSMs) and changes in clinical effects in each group after surgeries were analyzed by the Wilcoxon rank-sum test. For investigating the correlation between the two HSMs, the Spearman rank correlation analysis was performed. To assess the ability to discriminate health transition item(HTI) of the change of mJOA, recovery rate of mJOA, mental component score(MCS) and physical component score(PCS) of SF-36, receiver operating characteristic(ROC) curve was performed to distinguish the Somewhat Better from the About the Same patients. The accuracy of the ROC curve was evaluated by using the calculated area under the curve(AUC). To evaluate the most valid and responsive measure of the therapeutic effectiveness of CSM, AUC of the ROC curve and the correlations between responses to the anchor were calculated by Spearman rank correlation analysis. Results: The mean follow-up time was 50.5±10.3(24-84) months. The recovery rate of neurological function at 3 months, 1 year postoperatively and final follow-up was (45.0±42.4)％, (64.4±31.6)％ and (66.8±36.9)％ respectively. The scores of all sections of the SF-36 scale revealed that patients with CSM had significant impairment compared to the healthy adult(P＜0.05). After surgery, with the exception of general-health and social-function at three months after surgery, all the other items at every follow-up time showed significant improvement. PCS had a significant improvement(P=0.000) at 3 months after surgery except of MCS until 1 year after surgery(P value was 0.103 for MCS at 3 months after surgery compared with preoperation). PCS and MCS showed significant improvement at 1 year after surgery and final follow-up(P＜0.05). In terms of health transition item, the scores were 2.27±1.06, 1.84±0.90, 1.84±0.88 at 3 months, 1 year and final follow-up after surgery respectively. The improvement of mJOA was correlated with PCS at every follow-up and MCS at 1 year after surgery and final follow-up. At 3 months after surgery, the AUC(0.97) and correlation coefficient(-0.81) of PCS had the highest value of four indexes. While the recovery rate of mJOA was AUC=0.93, correlation coefficient =-0.82 at 1 year after surgery. As for the final follow-up, the results were not consistent, and the recovery rate of mJOA had the highest AUC(0.95) and the highest correlation coefficient(-0.67) was for MCS. Conclusions: The preoperative QOL of patients with CSM is severely impaired compared to the normal population and each domain of the SF-36 improves in varied degrees. At the early stage of recovery, the improvements in mJOA scores are essentially correlated with domains from the physical components of the SF-36, while at later stages associated with both domains. The most responsive indicator varies depending on the follow-up time.