One in four people with the implants need another surgery, usually within three years, new Australian study finds…

Not only are spinal cord stimulators largely ineffective for treating lower back pain, but a new study published in the Medical Journal of Australia has found almost one in four patients needs surgical reintervention to fix complications, usually within three years of having one implanted.

What did the researchers do

The team of Australian experts analysed data supplied by five private health insurers from 11451 admissions involving 5839 people who had a spinal cord stimulation-related surgical procedure between January 2011 and April 2022.

Of the 4361 people who received a definitive implant (rather than a trial implant), 1011 of them (23.2%) needed to undergo another procedure. The median time to first re-intervention was 16.8 months.

This finding further strengthens the case to urgently reconsider using spinal cord stimulators to manage lower back pain, says first author Dr Caitlin Jones, a postdoctoral research associate at the University of Sydney’s Institute of Musculoskeletal Health.

Harms linked with spinal cord stimulators

Dr Jones was also first author on a paper that found 522 adverse events reported to the TGA from July 2012 to January 2019 involved spinal cord stimulators. Most of these events (79%) were rated as severe, meaning they necessitated hospitalisation, Dr Jones explains.

Another 13% were classed as life-threatening—including haemorrhagic strokes associated with the procedure, pulmonary emboli, and one case where a tumour grew in the pocket housing the stimulator’s battery pack, Dr Jones says. There were five reports of death, although data was not sufficient to attribute these directly to the device or procedure.

Over half the reported harms were related to device malfunction—such as fracture or movement of the electrical lead—and others included infections, dural tears and unexplained increases in pain.

They also found that for every 10 devices implanted each year in Australia, four are removed.

Meanwhile, a 2023 Cochrane review concluded that spinal cord stimulation was probably no better than placebo at reducing pain or improving function or quality of life in people with lower back pain.

So, why are these devices still an approved back pain treatment?

Desperate patients driving demand

The desperation of people with chronic pain is one key reason, Dr Jones says.

“There’s not a whole lot of treatments that can help these people. And a lot that I’ve spoken to are willing to take these big risks in searching for something that helps,” she says.

But desperation is not a great foundation for choosing treatment, especially when the stakes are high.

“The risk of it actually making their pain worse is higher than it relieving their pain,” she says.

“I’ve got a lot of empathy for people who just want to try something, and their doctors want to offer them something. But in the case of spinal cord stimulators, you’re doing something that is more likely to make them worse than better. So it’s not a gamble that pays off in my books.”

She thinks a lot less people would agree to take the risk if they knew the truth about the likely benefits and harms involved.

Has regulation kept up with evidence?

In 2022, the TGA responded to increasing concerns about the safety and performance of these devices by launching a post-market review into all spinal cord stimulators included on the Australian Register of Therapeutic Goods (ARTG).

As a result, they removed 12 devices from the register and imposed conditions on the 70 others —such as asking sponsors to provide additional studies or imposing tighter restrictions on how they’re used and in which patients.

This review is ongoing, but Dr Jones is not overly impressed by its outcomes so far.

“We thought when they were undertaking this review, there would be published findings where they actually present what evidence they looked at and how they came to their conclusions, but it’s a lot less than that,” she says.

“I think the regulatory action being a bit behind the evidence is part of why there’s this mismatch between how often they’re used versus what we know about what they do.”

The TGA stands by its review

The TGA says the devices are generally used as a last line of treatment, and that careful patient selection is crucial.

“Appropriate patient selection for use of spinal cord stimulation and device suitability for individual conditions remain of utmost importance in the consideration of use of these devices,” the TGA said in a December update on the post market review.

A spokesperson for the TGA told Healthed that devices were removed from the ARTG where evidence was insufficient.

“To date, the evidence reviewed by the TGA indicates an acceptable risk-benefit profile, for the specified patient cohorts, for the devices that remain included on the Australian Register of Therapeutic Goods (ARTG),” the TGA spokesperson said.

The TGA declined to elaborate on appropriate patient selection. Some information has been published in evidence-based consensus guidelines in 2023 by the American Society of Regional Anesthesia and Pain Medicine.

Lucrative or costly, depending on who you ask

The MJA study found spinal cord stimulators cost health insurers an average of $55,000 each, with patients paying more out of their pockets.

Ninety percent of procedures are done in private hospitals, which hints that there is a financial incentive for putting them in, Dr Jones notes.

Some experts suggest industry influence, and promotion of the devices by the pain specialists who implant them, at least partly drives their continued use in Australia.

While the data for the most recent study was supplied by insurance companies, it wasn’t funded by them – but the Medical Technology Association of Australia told the Sydney Morning Herald that because private health insurers have an interest in avoiding paying for the high cost procedure, the fact the data came from them could potentially bias the outcome.

Dr Jones says their findings probably underestimate the actual number and cost of surgical reinterventions because some common device problems (such as the need to reposition leads without replacing the hardware) were not included in the dataset health insurers provided. Nor were people who elected to leave the device in place but turn it off captured in the dataset.

What can GPs do?

The TGA advises health professionals to give patients enough information to enable informed educated consent, and to continue reporting all adverse events associated with a spinal cord stimulation implant.

Dr Jones agrees it’s crucial to inform patients of the risks and benefits of spinal cord stimulation, adding that results are no better than a sugar pill or sham therapy.

“The risk of it actually making their pain worse is higher than it relieving their pain,” she says.

“If patients are more concerned about getting some relief regardless of the harm, then you might explain that the chance of having relief is really minuscule—and most likely there’ll be no relief. Are they more concerned about harms? You can focus in on that.”

Ideally, she recommends discussing this before they see a pain specialist about getting a stimulator, because by then they are likely to be committed to this pathway.

Dr Jones suggests recommending therapies with demonstrated effectiveness in chronic back pain, including exercise, education, cognitive behavioural therapy, sensorimotor retraining and cognitive functional therapy instead.