The impact of workers' compensation on outcomes of surgical and nonoperative therapy for patients with a lumbar disc herniation: SPORT

Abstract

Study design: Prospective randomized and observational cohorts.

Objective: To compare outcomes of patients with and without workers' compensation who had surgical and nonoperative treatment for a lumbar intervertebral disc herniation (IDH).

Summary of background data: Few studies have examined the association between worker's compensation and outcomes of surgical and nonoperative treatment.

Methods: Patients with at least 6 weeks of sciatica and a lumbar IDH were enrolled in either a randomized trial or observational cohort at 13 US spine centers. Patients were categorized as workers' compensation or nonworkers' compensation based on baseline disability compensation and work status. Treatment was usual nonoperative care or surgical discectomy. Outcomes included pain, functional impairment, satisfaction and work/disability status at 6 weeks, 3, 6, 12, and 24 months.

Results: Combining randomized and observational cohorts, 113 patients with workers' compensation and 811 patients without were followed for 2 years. There were significant improvements in pain, function, and satisfaction with both surgical and nonoperative treatment in both groups. In the nonworkers' compensation group, there was a clinically and statistically significant advantage for surgery at 3 months that remained significant at 2 years. However, in the workers' compensation group, the benefit of surgery diminished with time; at 2 years no significant advantage was seen for surgery in any outcome (treatment difference for SF-36 bodily pain [-5.9; 95% CI: -16.7-4.9] and physical function [5.0; 95% CI: -4.9-15]). Surgical treatment was not associated with better work or disability outcomes in either group.

Conclusion: Patients with a lumbar IDH improved substantially with both surgical and nonoperative treatment. However, there was no added benefit associated with surgical treatment for patients with workers' compensation at 2 years while those in the nonworkers' compensation group had significantly greater improvement with surgical treatment.

Figure 1

Flow diagram of enrollment and follow-up. The numbers of patients who completed follow-up or underwent surgery are cumulative during the 2-year follow-up period.

Figure 2

Outcomes of surgical treatment and nonoperative treatment in the workers' compensation and nonworkers' compensation groups during 2 years of follow-up. The graphs show adjusted as-treated analyses. Results for bodily pain and physical function are scores on the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36), ranging from 0 to 100, with higher scores indicating less severe symptoms. The Oswestry Disability Index ranges from 0 to 100, with lower scores indicating less severe symptoms. The horizontal dashed line in each of the two SF-36 graphs represents normal values adjusted for age and sex. The I bars represent 95% confidence intervals for the surgical groups, and the P values represent a global (area under the curve) comparison of surgical versus nonoperative treatment for workers' compensation and nonworkers' compensation groups. At 0 months, the floating data points represent the observed mean scores or proportions for each study group, whereas the data points on plot lines represent the adjusted mean scores from as-treated analyses.