By Pat Anson, PNN Editor

A large new study is raising questions about the long-term effectiveness of spinal cord stimulators and whether they really help patients reduce their use of opioids and other pain treatments.

Researchers at the University of California San Francisco (UCSF) School of Medicine analyzed health data for 1,260 patients who received permanent stimulators and found that — when compared to a control group — the devices did not reduce their use of opioids, epidurals, corticosteroid injections or radiofrequency ablation after two years. About a fifth of the patients experienced complications so severe the devices had to be removed or revised.

Spinal cord stimulators (SCSs) are considered an invasive treatment of last resort for people with chronic back or leg pain, because the devices have to be surgically implanted near the spine and connected to batteries placed under the skin. The implants send electrical impulses into the spine to mask pain.

About 50,000 SCSs are implanted annually in the U.S. and their use is growing – in part because of the belief they’ll reduce the need for opioids and other pain therapies.

But UCSF researchers found that SCS patients actually filled more opioid prescriptions after one year than a control group of pain patients (CMM) who did not get the devices. The use of other medications and procedures by SCS patients declined slightly after one year, but there were no significant differences between the two groups after two years.

“The lack of reduction in pharmacotherapy, epidural and facet corticosteroid injections, and radiofrequency ablations at 2 years among patients receiving SCS compared with those receiving CMM suggests that SCS was providing insufficient pain relief to forego other therapies or improve rates of depression or anxiety, as prescriptions for these drug classes did not decline,” lead author Sanket Dhruva, MD, an Assistant Professor of Medicine at UCSF, wrote in JAMA Neurology.

“Because most patients still had their permanent SCS in place at 2 years, some may receive prolonged benefit from this modality, although we were not able to identify this through reductions in opioid use or nonpharmacologic pain interventions.”

Researchers also found that the total cost of care was about $39,000 higher for SCS patients in the first year, while health costs were similar for the two groups in the second year.

‘Sobering Insights’

"The findings appear to belie the popular belief that SCS may result in reduced opioid medication usage or overall fewer physician visits in the years immediately following device implant," wrote Prasad Shirvalkar, MD, and Lawrence Poree, MD, both from the UCSF Division of Pain Medicine, in an accompanying editorial.

“Using robust propensity matching, the present study provides sobering insights that SCS does not appear to reduce chronic opioid use or the utilization of health care resources compared with CMM in the first 2 years after implant. We believe this will help mitigate excessive enthusiasm of SCS as a panacea for chronic pain syndromes and illuminate biases of SCS hype cycle that can possibly be fueled by industry-related conflicts of interest.”

Stimulators are no longer limited to patients with chronic back, neck and leg pain. Last year the FDA expanded the use of SCSs to include pain from diabetic neuropathy. Stimulators are also now being used on patients with Complex Regional Pain Syndrome (CRPS).

A 2018 study by a team of investigative journalists found that SCSs have some of the worst safety records of medical devices tracked by the FDA. A 2020 FDA review of adverse events involving stimulators found that nearly a third were reports of unsatisfactory pain relief. The review also identified nearly 500 deaths linked to the devices, along with nearly 78,000 injuries and 30,000 device malfunctions.