Summary: According to a new study, spinal cord stimulation does not provide long-term relief for back pain and may actually cause harm to a patient.
Source: University of Sydney
Spinal cord stimulation, a medical technology suggested to treat people with chronic back pain, does not provide long-term relief and may cause harm, according to a Cochrane Review released today.
Spinal cord stimulation is thought to work by implanting a device that sends electrical pulses to the spinal cord to interrupt nerve signals before they get to the brain.
The study reviewed published clinical data on spinal cord stimulation. This included randomized controlled trials, considered to be the most robust method to measure effectiveness of a treatment in medical research.
The researchers analyzed the results of 13 clinical trials, looking at data from 699 participants, comparing spinal cord stimulation treatment with placebo or no treatment for low back pain.
Cochrane reviews are trusted by researchers, medical professionals and policymakers because they use robust methodologies to combine evidence from multiple sources, reducing the impact of bias and random error that can make individual studies less reliable.
The review concluded that spinal cord stimulation is no better than a placebo for treating low back pain, with probably little to no benefit for people with low back pain or improvement in their quality of life.
There was little to no clinical data regarding the long-term effectiveness of spinal cord stimulation.
The researchers also found that adverse side effects to the surgery were poorly documented overall, preventing them from concluding the level of risk involved. Harms from spinal cord stimulation could include nerve damage, infection, and the electrical leads moving, all of which may need repeated surgeries.
The review findings have been submitted to the Federal Department of Health and Aged Care prosthesis list review taskforce. The taskforce is reviewing the eligibility of current prostheses subsidized by Medicare.
In Australia, the devices’ long-term safety and performance are also being re-assessed by The Therapeutic Goods Administration (TGA), the country’s regulatory authority for therapeutic goods.
“Spinal cord stimulation is invasive and has a great financial cost to people who choose surgery as a last resort to alleviate their pain. Our review found that the long-term benefits and harms are essentially unknown,” said lead researcher Dr. Adrian Traeger from Sydney Musculoskeletal Health, an initiative of the University of Sydney, Sydney Local Health District and Northern Sydney Local Health District.
“Our review of the clinical data suggests no sustained benefits to the surgery outweigh the costs and risks.
“Low back pain is one of the leading causes of disability worldwide. Our findings further emphasize the urgent need to review funding arrangements for chronic pain care to help patients in their search for relief. There are evidence-based physical and psychological therapies for back pain; ensuring access to these is essential.”
The review team found multiple gaps in clinical data.
There were no studies that investigated the long-term (more than 12 months) impact of spinal cord stimulation on low back pain. The longest was a single six-month trial.
The majority of clinical trials only looked at the immediate impact of the device, which is a time frame of less than a month.
The review team provided a list of recommendations, including that future spinal cord stimulation clinical trials be at least 12 months, clearly document the number of people who experience adverse events and make comparisons with other pain treatment options.
Professor Chris Maher, Co-Director of Sydney Musculoskeletal Health, said, “Our review found that the clinical benefit of adding spinal cord stimulation to treat low back pain remains unknown. When coupled with the reality that these devices are very expensive and often break down there is clearly a problem here that should be of concern to regulators.”
A separate Cochrane review, in which the researchers were not involved, examined the effect of spinal cord stimulation versus placebo in people with chronic pain. Similar to this review, it concluded there was a lack of evidence to suggest long-term benefits in treating chronic pain.
About this neurotech and pain research news
Original Research: Open access.
“Spinal cord stimulation for low back pain” by Adrian Traeger et al. Cochrane Database of Systematic Reviews
Spinal cord stimulation for low back pain
Spinal cord stimulation (SCS) is a surgical intervention used to treat persistent low back pain. SCS is thought to modulate pain by sending electrical signals via implanted electrodes into the spinal cord. The long term benefits and harms of SCS for people with low back pain are uncertain.
To assess the effects, including benefits and harms, of SCS for people with low back pain.
On 10 June 2022, we searched CENTRAL, MEDLINE, Embase, and one other database for published trials. We also searched three clinical trials registers for ongoing trials.
We included all randomised controlled trials and cross‐over trials comparing SCS with placebo or no treatment for low back pain. The primary comparison was SCS versus placebo, at the longest time point measured in the trials. Major outcomes were mean low back pain intensity, function, health‐related quality of life, global assessment of efficacy, withdrawals due to adverse events, adverse events, and serious adverse events. Our primary time point was long‐term follow‐up (≥ 12 months).
Data collection and analysis
We used standard methodological procedures expected by Cochrane.
We included 13 studies with 699 participants: 55% of participants were female; mean age ranged from 47 to 59 years; and all participants had chronic low back pain with mean duration of symptoms ranging from five to 12 years. Ten cross‐over trials compared SCS with placebo. Three parallel‐group trials assessed the addition of SCS to medical management.
Most studies were at risk of performance and detection bias from inadequate blinding and selective reporting bias. The placebo‐controlled trials had other important biases, including lack of accounting for period and carryover effects.
Two of the three parallel trials assessing SCS as an addition to medical management were at risk of attrition bias, and all three had substantial cross‐over to the SCS group for time points beyond six months. In the parallel‐group trials, we considered the lack of placebo control to be an important source of bias.
None of our included studies evaluated the impact of SCS on mean low back pain intensity in the long term (≥ 12 months). The studies most often assessed outcomes in the immediate term (less than one month).
At six months, the only available evidence was from a single cross‐over trial (50 participants). There was moderate‐certainty evidence that SCS probably does not improve back or leg pain, function, or quality of life compared with placebo. Pain was 61 points (on a 0‐ to 100‐point scale, 0 = no pain) at six months with placebo, and 4 points better (8.2 points better to 0.2 points worse) with SCS.
Function was 35.4 points (on a 0‐ to 100‐point scale, 0 = no disability or best function) at six months with placebo, and 1.3 points better (3.9 points better to 1.3 points worse) with SCS. Health‐related quality of life was 0.44 points out of 1 (0 to 1 index, 0 = worst quality of life) at six months with placebo, and 0.04 points better (0.16 points better to 0.08 points worse) with SCS.
In that same study, nine participants (18%) experienced adverse events and four (8%) required revision surgery. Serious adverse events with SCS included infections, neurological damage, and lead migration requiring repeated surgery. We could not provide effect estimates of the relative risks as events were not reported for the placebo period.
In parallel trials assessing SCS as an addition to medical management, it is uncertain whether, in the medium or long term, SCS can reduce low back pain, leg pain, or health‐related quality of life, or if it increases the number of people reporting a 50% improvement or better, because the certainty of the evidence was very low.
Low‐certainty evidence suggests that adding SCS to medical management may slightly improve function and slightly reduce opioid use. In the medium term, mean function (0‐ to 100‐point scale; lower is better) was 16.2 points better with the addition of SCS to medical management compared with medical management alone (95% confidence interval (CI) 19.4 points better to 13.0 points better; I2 = 95%; 3 studies, 430 participants; low‐certainty evidence).
The number of participants reporting opioid medicine use was 15% lower with the addition of SCS to medical management (95% CI 27% lower to 0% lower; I2 = 0%; 2 studies, 290 participants; low‐certainty evidence). Adverse events with SCS were poorly reported but included infection and lead migration. One study found that, at 24 months, 13 of 42 people (31%) receiving SCS required revision surgery.
It is uncertain to what extent the addition of SCS to medical management increases the risk of withdrawals due to adverse events, adverse events, or serious adverse events, because the certainty of the evidence was very low.
Data in this review do not support the use of SCS to manage low back pain outside a clinical trial. Current evidence suggests SCS probably does not have sustained clinical benefits that would outweigh the costs and risks of this surgical intervention.