Work-Related Chronic Low Back Pain

Return-to-Work Outcomes After Referral to Interventional Pain and Spine Clinics

Rathin N. Vora, MD, MPH; Bruce A. Barron, MD, MS; Anthony Almudevar, PHD; Mark J. Utell, MD


Spine. 2012;37(20):E1282-E1289. 

In This Article


To summarize, our findings demonstrated that patients not referred to PTC/SC had better return-to-work and pain outcomes than those who were referred. The study also showed that return to work and pain improvement were strongly associated with the TSI. In addition, we found a direct correlation between pain levels and functional outcomes, that is, as pain levels worsen, return-to-work outcomes worsen.

Low back injuries have historically been one of the most common work-related injuries. Much of the literature has evaluated modalities such as functional restoration programs in improving outcomes in LBP.[19] To our knowledge, this is the first study to evaluate return to work in chronic low back work-related injuries based on treatment in a PTC/SC.

As we explored the aforementioned results further to evaluate factors that may have contributed to our findings, we found that TSI was a very strong contributor, that is, as the TSI increased, the potential for functional improvement decreased irrespective of the referral pattern. We also observed a difference in outcomes in the 2 clinics from where the study patients were referred. Most of this difference can be explained by the longer TSI at OEM than at FLOHS. It was also observed that as the pain level worsened, the functional level also worsened. Therefore, the level of pain seemed to have adversely affected functionality to some extent.

A recent study by Nguyen et al[20] looked at long-term outcomes of lumbar fusion among worker's compensation patients in Ohio. They found that 2 years after fusion surgery, 26% of fusion cases had returned to work, whereas 67% of nonsurgical controls had returned to work (P < 0.001) within 2 years from the date of injury. They also reported time off work (or time off work prior to surgery) as a significant factor that predicted poor functional outcomes. They concluded that lumbar fusion for the diagnoses of disc degeneration, disc herniation, and/or radiculopathy in a workers' compensation setting was associated with poor return-to-work status. Our study showed poorer functional outcomes in patients referred to PTC/SC. However, our findings indicated that the major reason for a similar finding was likely related to longer TSI.

One major strength of this study was the extensive data set collected through detailed chart review of every patient. In addition, the 2 clinics, although different from each other, were thought to be representative of typical cases of work-related LBP in the greater Rochester region and could be reasonably generalized to workers' compensation injuries at the national level.

The major limitation of this study was its retrospective study design. In addition, we did not have specific predetermined criteria for the referral and nonreferral groups, because specific nationally accepted criteria for referral to a PTC/SC do not exist. In general, all patients whose medical condition did not improve significantly after at least 8 weeks of similar conservative care were considered for referral. It should be noted that confounding may have played a role in this study, that is, patients least likely to improve were likely referred to the PTC/SC. In general, physician judgment and perceived patient benefit are the basic criteria used in referring patients to PTC/SC in most clinical practices today as was in our study. The number of patients was not large enough to evaluate specific interventional modalities in the referred group. It should also be noted that inherent to the workers' compensation system is the link between issues of disability and compensability, which may affect outcomes in those with chronic disability. However, this study specifically evaluated only work-related low back injuries in both the referred and the nonreferred groups. Finally, our findings should not be extrapolated to non–work-related low back injuries.

Several important implications for clinical practice arise from these findings. First, our results clearly revealed that functional improvement decreased as the TSI increased (Figure 3). In general, there was very little change in functional improvement after 6 months of TSI. Second, we found that current referral patterns and timing of referral to PTC/SC as a form of last resort, when the condition is chronic and all else has failed, do not result in improved work status outcomes. This strategy increases the likelihood of PTC/SC failure even before treatment has started.

Figure 3.

Graph showing relation between functional change and time since injury in the non–referral group. The graph shows that the largest functional change (improvement in return-to-work status) occurred early on in the injury, with the amount of improvement dropping off considerably after 1 year of injury in patients who were not referred to the pain clinic. The referral group was not included because there was little improvement in their functional improvement as demonstrated in Figure 2. TSI indicates time since injury; FI, function improvement.

This study has also laid important groundwork for future work in this area. The lack of clinical criteria for referral to PTC/SC poses a major limitation for both medical care and research in this area and needs to be addressed. Establishing defined criteria would help clinicians refer appropriate patients to PTC/SC. These criteria would also help further in the area of outcomes-based research. To further elucidate our findings, we recommend a prospective trial in which patients would be randomized to PTC/SC referral or no referral at a specified referral center and at a specified time after their injury, for example, 6 weeks after injury, to assess outcomes. Finally, all future workers' compensation low back injury studies should take into account the TSI, because this is one of the most important factors in predicting outcomes.