Prediction of Objectively Measured Physical Activity and Self-Reported Disability Following Lumbar Fusion Surgery.
To investigate the predictive value of preoperative fear-avoidance factors (self-efficacy for exercise, pain catastrophizing, kinesiophobia, and depression), walking capacity, and traditional predictor variables for predicting postoperative changes in physical activity level and disability 6 months after lumbar fusion surgery in patients with chronic low back pain (LBP). We prospectively enrolled 118 patients scheduled for lumbar fusion surgery for motion-elicited chronic LBP with degenerative changes in 1-3 segments of the lumbar spine. Associations between the predictors and the dependent variables were investigated with multiple linear regression analysis. Dependent variables were physical activity level as objectively measured with a triaxial accelerometer and disability as measured with the Oswestry Disability Index. Preoperative physical activity level (β = -0.349; P < 0.001) and self-efficacy for exercise (β = 0.176; P = 0.021) were significant predictors of the postoperative change in physical activity. Preoperative disability (β = -0.790; P < 0.001), self-efficacy for exercise (β = 0.152; P = 0.024), and pain catastrophizing (β = 0.383; P = 0.033) were significant predictors for the change in the Oswestry Disability Index. Patients with low levels of preoperative physical activity were more likely to increase their level of physical activity after lumbar fusion surgery, especially when their self-efficacy for exercise was high. However, most of these patients still had low levels of physical activity after surgery, and they may therefore need extra support in increasing their postoperative physical activity levels.