Is type of compensation a predictor of outcome after lumbar fusion?

STUDY DESIGN

Propensity-matched case-control study.

OBJECTIVE

To examine the impact of compensation status on clinical outcomes after lumbar spine fusion.

SUMMARY OF BACKGROUND DATA

Workers' compensation has been associated with inferior outcomes after treatment of low back pain. However, patients receiving other forms of compensation, such as long-term disability or government-supported insurance, have not been studied independently.

METHODS

Patients with complete preoperative and 2-year postoperative data, including Oswestry disability index, 36-item short form health survey, and numeric rating scales for back and leg pain, after 1- or 2-level posterolateral lumbar fusion from a single spine surgery practice, were retrospectively identified. Fifty-nine patients 50 years or younger receiving disability compensation and 38 patients receiving workers' compensation were identified from 1144 patients with complete outcome measures. Propensity scoring was used to match cohorts not receiving compensation. Each group was matched for sex, age, smoking status, body mass index, surgical indication, number of levels fused, and baseline outcome measures. Fifty-one and 37 matched pairs were successfully identified for disability and workers' compensation cohorts, respectively.

RESULTS

Consistent with propensity matching, no statistically significant difference between cohorts was observed for demographics and baseline outcome measures. At 2-year follow-up, the disability compensation group demonstrated similar degrees of improvement for all outcome measures compared with its matched nondisability cohort, whereas the workers' compensation group demonstrated less improvement than its matched cohort.

CONCLUSION

This study demonstrates a difference in outcomes after lumbar spinal fusion between long-term disability and workers' compensation populations. Although, these populations achieve only marginal improvement, it seems that the type of compensation status influences outcome. Workers' compensation has a clear, negative influence on outcome when compared with controls, whereas well-selected patients receiving disability compensation seem more likely to benefit from lumbar fusion. Therefore, surgeons and researchers alike should not include disability compensation patients in the same cohort as patients on workers' compensation.