Does Spinal Cord Stimulation Improve Diabetic Neuropathy?

Rod S. Taylor, MSc, PhD; Mark Harmel, MPH, CDCES


October 19, 2022

This transcript has been edited for clarity.

Good afternoon. I'm going to talk to you about the SENZA-PDN trial. This is a randomized controlled trial conducted in patients with peripheral diabetic neuropathy. It's a really important indication because these people suffer from large losses in their quality of life. Although we can treat these patients' pain with analgesics, often these therapies aren't effective.

In this trial, we took 216 patients in the United States across 18 centers who had their peripheral diabetic neuropathy for at least a year in spite of taking usual-care medication. They also had to have a pain VAS > 5 on a scale where 0 represents no pain and 10 max pain.

We randomized them to continue with their usual medical management, which in this case was analgesic treatment, or to usual care plus a new technology that I'm very excited to talk to you about today, which is called spinal cord stimulation.

The patients we recruited who received the spinal cord stimulator demonstrated much improved levels of pain and quality of life compared with the usual-care group, who virtually did not change their level of pain or their quality of life compared with their baseline assessment.

I'm going to focus on what happened after that 6-month period. One of the things we did in the trial design was to allow patients to cross over if they failed to get therapeutic benefit from the therapy they were receiving. Given that, we observed that 90% of patients elected to cross over from their usual care to receiving a spinal cord stimulator.

We followed up with everybody for an additional 18 months. We looked at their data out to 24 months and what we found was very interesting. Essentially, the improvements that we saw at 6 months were continued to 24 months in both the group that received spinal cord stimulation at the outset and in those who crossed over and received a spinal cord stimulator at 6 months.

Of course, the importance of that observation is that these benefits aren't just short term but indeed are sustained over a 2-year period in those who received a stimulator from the outset. That's important because when you do these trials, one of the things that can happen when you're measuring patient-reported outcomes is a placebo effect.

Are these improvements in the stimulator arm purely due to people knowing they're getting something additional to their care? Usually placebo effects tend to dissipate in the longer term. The fact that we now have these longer-term data, I think you would agree, provides further support that this intervention with spinal cord stimulation may be an effective one for this population of people with painful diabetic neuropathy.

What are the implications of these findings? First, we need to recognize that spinal cord stimulation is not a routine therapy currently available for people with painful diabetic neuropathy. Indeed, if you look across the globe, whether you're in the United States, Europe, or wherever, clinical guidelines do not currently recommend spinal cord stimulation. Of course, with this evidence, we anticipate clinical guidelines being updated in the future to reflect this.

Working on the basis, then, that we do have a therapy for patients, how might we make this available? What would be involved? First, spinal cord stimulation is a technology we've had available for the better part of three decades, and we've traditionally used it in the treatment of people with chronic low back pain. We know what this therapy is and we know how to do it.

What does it involve? It involves bringing the patient into the hospital after an initial period of assessment. They will go into the OR — the technology is very similar to a cardiac pacemaker — and it is implanted into their lower back. Under the skin is a battery attached to two leads, and those leads are then effectively implanted under local anesthetic into the intrathecal space of the spinal cord.

The clinician will then test with the patient on the slab to check that they've got the sweet spot where, if they activate the stimulator, the patient perceives an improvement in their pain. Once that's done, we close up the wound, and the patient is allowed to go out, be fully ambulant, and effectively undertake what we call a trial period, which can be up to maybe a month, where they wear the device. We will give them a diary, ask them to record their pain scores, and then bring them back.

If that all goes well, we'll then perform what we call a permanent implant. We will finalize the implementation of the implant and then the patient can go out from the clinic and wear the device during their normal activity.

What we've found in the chronic low back pain areas is that these people can get benefit from these devices over the longer term. I've talked about 24 months. Typically, the battery life of these devices now is as long as 8 or 9 years. We will certainly have to bring the patient back on an annual basis to assess them. At some point, we may also need to change their battery. That's a very simple procedure to do under local anesthetic.

We've heard the evidence. How do I go about accessing this technology? It's important to say that the regulators, both in the United States (the FDA) and in Europe, have approved this technology as clinically efficacious and safe. However, in Europe and in the United States, this technology has not routinely been recognized by insurance or for availability within the UK National Health Service.

For that to happen, both insurers and bodies, such as the National Institute for Health and Care Excellence in the UK, need to take the advice I've talked to you about today, examine the robustness, look at issues such as cost-effectiveness, and then make a final decision on whether this technology would represent good value for money for populations, be that based in North America, Europe, or elsewhere in the globe.

The technology is not available to the patient just yet, but we hope that that decision-making will follow in the coming months or a couple of years.

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