Review of SCS For Chronic LBP Draws Criticism

A group of pain physicians has asked the Cochrane Library to retract a review on spinal cord stimulation (SCS) for the treatment of chronic low back pain (CLBP). The request appeared as a commentary article led by Shravani Durbhakula, MD, MPH, MBA, an assistant professor of pain medicine in the Department of Anesthesiology and Critical Care Medicine at Johns Hopkins School of Medicine, in Baltimore, that appeared in Pain Medicine (2023;24[8]:923-925).

The Cochrane Review concluded that the evidence did not support the use of SCS to manage chronic low back pain outside of a clinical trial. “Current evidence suggests spinal cord stimulation probably does not have sustained clinical benefits that would outweigh the costs and risks of this surgical intervention,” wrote the authors of the review.

Durbhakula and colleagues wrote that the retraction was necessary because of “striking errors in the methodology, execution and conclusions” of the review (Cochrane Database Syst Rev 2023;3[3]:CD014789) led by Adrian Traeger, MD, of the Institute for Musculoskeletal Health, a division of the School of Public Health in the University of Sydney. “The authors of the Cochrane review extrapolate questionable findings to generate overreaching conclusions that have the potential to negatively impact the care of patients with chronic low back pain,” according to Durbhakula’s team.

Durbhakula said the review’s researchers were incorrect in excluding large, multicenter, comparative effectiveness trials and pragmatic studies—such as those comparing SCS with revision decompression and/or fusion surgery, and tonic SCS with novel waveforms.

“While we agree that placebo- and sham-controlled trials represent the highest level of scientific evidence, paresthesia-free waveforms which enable randomized, double-blind studies were developed merely over a decade ago,” Durbhakula and colleagues wrote.

“Furthermore, independent physician investigators have struggled to complete these studies as they are expensive to perform, and recruitment is difficult for sham-controlled spinal cord stimulation trials. Meanwhile, industry is disincentivized from performing such studies, as the [FDA] does not require them for regulatory approvals in the presence of a predicate device; they are costly and hard to accrue patients into; and the risk–benefit ratio does not favor companies and their shareholders,” they wrote. These historical limitations explain both the dearth of literature in this category and why the few published sham-controlled studies are smaller, single-center studies.”

The retraction request article states that while high-quality, placebo-controlled studies of SCS for CLBP are indeed needed, there is an abundance of Level 1 comparative effectiveness data that support the efficacy of SCS for CLBP. “These studies have long-term follow-up and answer key clinical questions, such as defining the optimal spinal cord stimulation waveform for a specific patient phenotype, and whether spinal cord stimulation provides outcome and cost benefits over revision decompression and/or fusion surgery,” wrote Durbhakula’s team. “The summation of these data demonstrates large magnitudes of effect, although with indirectness and potential for risk of bias. As such, GRADE [Grading of Recommendations, Assessment, Development, and Evaluations] assessment should reveal moderate-certainty evidence of medium- to long-term effectiveness of spinal cord stimulation for CLBP.”

According to Durbhakula’s group, Traeger et al identified parallel trials evaluating SCS and conventional medical management against conventional management alone; however, their interpretation of these studies and handling of inclusion and exclusion were misguided. The authors’ conclusions about SCS’s probable lack of efficacy rested solely on the Hara et al study (JAMA 2022;328[5]:1506-1514), a placebo-controlled trial with medium-term follow-up. This study had multiple flaws, which have been pointed out by expert pain physicians and clinical scientists in the neuromodulation field from around the world, according to the retraction request.

“Generalizations about CLBP care interventions, drawn from data limited by narrow search criteria, are problematic and misleading,” Durbhakula and colleagues wrote. “The reader is left questioning whether Traeger et al intended to provide a balanced assessment of the published literature on SCS for CLBP from conception, given their 2020 letter to the editor and stated conflicts of interest that include royalties from two books: 1) “Surgery, the Ultimate Placebo” and 2) “Hippocrasy: How Doctors Are Betraying Their Oath.” Furthermore, while a pain physician was acknowledged at the end of the publication, the extent of this physician’s involvement was too limited to warrant authorship. Inclusion of a physician author with content expertise in pain medicine and neuromodulation could have offered insight into the limitations addressed here, provided a balanced interpretation of the published literature, and aided with recommendations of appropriate scope.”

—Kate O’Rourke

Durbhakula reported consulting payments from Averitas Pharma and Biotronik. Traeger provided paid consultancy on models of physiotherapy care to a health service provider in 2017.