Emotional health predicts pain and function after fusion: A prospective multicenter study

Study Design. Prospective. Objectives. To assess whether patients with poorer emotional health before fusion surgery will have worse pain and function after surgery, and to identify patient variables that predict fusion outcomes. Summary of Background Data. A systematic review of fusion outcomes studies reported an average of 68% "satisfactory" outcomes. The persistence of pain and functional limitations leads to emotional and financial costs. Therefore, it is important to identify the factors that affect fusion outcome. Research has explored psychosocial factors (e.g., depression, anxiety) as being important outcome predictors. Methods. Data from subjects enrolled in a multisite trial of 2 fusion systems were analyzed. Subjects completed measures of health-related quality of life (SF-36), pain (visual analog scale), and function (Oswestry Disability Index). A total of 160 subjects completed measures before fusion, 155 completed measures 12 months after fusion, and 115 completed measures 24 months after fusion. Subject variables (i.e., age, gender, smoking, workers' compensation, and second surgery status) and presurgical pain/function were regressed on pain/function outcomes after surgery. This model was compared to one that included presurgical Mental Component Scores (MCSs), which is a SF-36 derived measure of emotional health, to determine whether MCS data significantly improved the prediction of pain/function. Results. Higher presurgical MCS (i.e., better emotional health) predicted less back and leg pain after surgery. Similarly, higher presurgical MCS predicted better physical function after surgery. Other important predictors of pain and function were presurgical pain and function, workers' compensation, and smoking status. The associations were modest (2% to 9% of independent variance accounted for), but significant. Conclusions. Presurgical emotional status is one significant predictor of pain and function outcomes up to 2 years after fusion. Other significant predictors included workers' compensation status, smoking status, and presurgical pain/function. Studies to identify and intervene with patients with poorer emotional status will clarify whether presurgical mental health intervention can improve pain and function outcomes after surgery or whether these patients are not candidates for surgery.