In the February 15 issue, Dr. Nguyen and colleagues reported on the dismal return to work (RTW) rate for worker’s compensation (WC) patients following lumbar fusion for degenerative disease. While this may seem like just another article to throw on the stack of papers demonstrating the poor outcomes of WC patients across the spectrum of orthopaedic and spinal conditions, what is striking about this article is how terrible the outcomes actually were. The study compared 725 WC patients with lumbar degenerative conditions who underwent fusion to 725 similar WC patients who were treated non-operatively and demonstrated that by five years only 26% of the fusion patients had returned to work compared with 67% of non-operative patients. Additionally, patients who underwent fusion actually increased their long-term use of narcotics from baseline. Are these results surprising? Given what we know about lumbar fusion for degenerative disk disease (DDD) and WC patient outcomes across most orthopaedic conditions, maybe not. No study has shown a marked benefit of fusion compared to non-operative treatment for DDD, even in the best of patients, while many have shown no benefit at all. While the SPORT study showed a large benefit of diskectomy compared to non-operative treatment for disk herniation patients overall, WC patients had minimal benefit even with this well-proven operation.1 In this study, the combination of questionable indications for surgery (i.e. the majority of patients underwent fusion for DDD for disk herniation) and a patient population known for poor outcomes resulted in bad surgical results.
Given these poor results, should we stop performing fusion on WC patients? Unfortunately, this study was not designed to answer this question, even though the answer may seem obvious. In order to answer this question, a prospective randomized trial comparing fusion to non-operative treatment for specific diagnoses in the WC population would need to be performed. This study suffers from the same problems as most retrospective, observational studies, namely the inability to control for the baseline differences between the groups being compared. While the two groups were similar on most measured variables, there were important differences in education, gender, and smoking status, all markers for important psychosocial differences that were not measured. Additionally, the surgery patients were by definition different since they were both offered surgery and chose to have it. Unmeasured differences between the groups likely included severity of disease, motivation to improve, coping skills, and beliefs about recovery from back pain. Since these factors were not measured, the authors were unable to control for them in their analyses, and they likely confounded the relationship between treatment and RTW. Another issue is the use of RTW as the main outcome measure without the use of a validated clinical outcome measure. While SPORT demonstrated a marked benefit of surgery for disk herniation, spinal stenosis, and degenerative spondylolisthesis on the SF-36 and Oswestry Disability Index, surgery did not result in a higher RTW rate compared to non-operative treatment.2-4 This suggests that RTW is a highly complex outcome dependent on many psychosocial and economic factors in addition to functional status. Since validated clinical outcomes were not measured, we cannot conclude anything about the functional status or pain levels of the two groups. Despite the inability to conclusively answer the question of whether or not we should perform fusion on WC patients, this study certainly causes one to question our ability to help this population with surgery. These data should be shared with WC patients making treatment decisions. It seems likely that if they were aware that they only had a 26% chance to RTW and would likely increase their narcotic usage following fusion that their enthusiasm for surgery might wane.
Please read Dr. Nguyen’s article and accompanying commentary. How will these data affect how you treat WC patients with degenerative lumbar conditions? Let us know by leaving a comment on The Spine Blog.
Adam Pearson, MD, MS
1. Atlas SJ, Tosteson TD, Blood EA, Skinner JS, Pransky GS, Weinstein JN. The impact of workers' compensation on outcomes of surgical and nonoperative therapy for patients with a lumbar disc herniation: SPORT. Spine (Phila Pa 1976) 2010;35:89-97.
2. Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical versus nonoperative treatment for lumbar disc herniation: four-year results for the Spine Patient Outcomes Research Trial (SPORT). Spine 2008;33:2789-800.
3. Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical versus nonoperative treatment for lumbar spinal stenosis four-year results of the Spine Patient Outcomes Research Trial. Spine (Phila Pa 1976) 2010;35:1329-38.
4. Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical versus nonsurgical therapy for lumbar spinal stenosis. The New England journal of medicine 2008;358:794-810.