Background: Spinal cord compression may lead to numerous symptoms and decreased functional capabilities. Causes include spinal stenosis, herniated disks, tumors, and spinal cord injury. Surgical outcomes are difficult to predict, especially those related to changes in patient functional capabilities. In this study, we sought to: 1) determine the predictors of change in disability and pain for spinal surgery patients, and 2) evaluate the relationship between pain and disability outcomes.
Methods: A single arm, 24-month cohort, repeated measures study of spinal surgery patient outcomes was performed in adult patients with spinal cord compression for which a surgical procedure was performed between June 2013 and December 2015, and with at least six months post-surgery data (N=76). Using linear regression, clinical and demographic parameters were evaluated as predictors of reduction in functional disability and pain, as measured by Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for Pain, respectively. The interaction between change in pain and functional disability was also evaluated.
Results: Changes from baseline were significant (p<0.05) for both the Oswestry Disability Index score (-0.13, 0.086-0.178), and Visual Analog Scale for Pain (-0.20, 0.129-0.268). Significant predictors for reduction in pain were pre-surgery pain and disability, prior spinal surgery history, age, alcoholic consumption, and microdiscectomy intervention. Predictors for reduction in disability were pre-surgery pain and disability, duration of symptoms, weight, resection, instrumentation, and laminectomy. Additionally, reduction in pain was found to be a significant confounder (>10% change in effect estimate with and without confounder) in the analysis, strongly affecting the impact of some predictors.
Conclusions: The results of this study suggest that postsurgical reduction in pain may be more amenable to prediction than reduction in disability. In addition, the relationship between spinal surgery disability and pain outcomes may be one of the factors that make prediction of surgical outcomes difficult. We recommend that future research, seeking to identify predictors of spinal surgery outcomes, be carefully designed to take into account the impact of pain on disability.