The reliability of quality of life evaluation using SF-36 and its correlation with neurological function assessment in Chinese patients with cervical spondylotic myelopathy

English Keywords:Cervical spondylotic myelopathy  Reliability  SF-36  modified Japanese Orthopaedic Association

English Abstract:

  【Abstract】 Objectives: To calculate the reliability of SF-36 and to verify its consistency with neurological function assessment after surgery for Chinese cervical spondylotic myelopathy(CSM) patients. Methods: The data of 142 CSM patients (male=84, female=58, average age was 60.0 years old, SD=10.9) who underwent surgical treatment were prospectively collected. Both neurological measurement (modified Japanese Orthopaedic Association, mJOA score) and quality of life (QOL) measurement (SF-36) were used to evaluate patients in this study preoperatively and at the follow-up of 3-month, 1-year and over 2-year postoperatively. The results of SF-36 evaluation in CSM patients were compared with that of healthy adults. Cronbach α was used to assess the reliability of 8 domains of SF-36. We also analyzed the consistency of domains of SF-36 with mJOA score at different follow-up time points. Based on the changing trends of each scale, we calculated the peak recovery time of CSM patients during the follow-up period. Results: The scores for all SF-36 domains except for mental health domain indicated that patients with CSM were significantly impaired compared with healthy adults. Cronbach α ranged from 0.73 (for role-emotional) to 0.85 (for physical functioning). (Cronbach α: physical functioning=0.85, role-physical=0.83, bodily pain=0.80, general health=0.81, vitality=0.81, social functioning=0.79, role-emotional=0.73, mental health=0.75). At the 3-month follow-up, improvements in mJOA scores were only significantly correlated with the patient′s scores of physical functioning and bodily pain. [Correlation coefficient(CC)(R): physical functioning=0.32, bodily pain=0.20; P<0.05]. At 1 year after surgery, improvements in mJOA scores were significantly correlated with physical functioning, general health, social functioning and role-emotional [CC(R): physical functioning=0.39, general health=0.24, social functioning=0.22, role-emotional=0.19; P<0.05]. While at final follow-up, improvements in mJOA scores were significantly correlated with physical functioning, vitality and role-emotional [CC(R): physical functioning=0.38, vitality=0.20, role-emotional=0.20; P<0.05]. The physical component score(PCS) peaked at 17.7 months and the mental component score(MCS) at 18.9 months, respectively. Conclusions: SF-36 is a reliable method to evaluate patients with CSM. The evaluation of quality of life was inconsistent with the neurological function improvement in different stages of the postoperative follow-up. At the early stage of recovery, the improvements in mJOA scores essentially correlated with domains from the physical components of the SF-36, while at later stages the improvements were associated with domains from both physical and mental components.