Effect of lumbar spinal fusion surgery on the association of self-report measures with objective measures of physical function

The lack of association between self-reported questionnaires and objective measures of function before surgery was likely due to psychological distress, correlating with emotional and cognitive function rather than true functional capacities. The influence of these psychological factors might be reduced after surgery due to a reduction of low back pain. To obtain an accurate assessment of impairment, there is a need to evaluate function by measuring objective physiologic parameters that are unsusceptible to voluntary or affective influences.