Spinal Cord Stimulation for PDN: Science Fiction or Ready for Primetime?

Erika Petersen, MD

When discussing advances in the care of patients with diabetes in recent years, much of the discussion has focused on pharmacologic therapies and advances in continuous glucose monitoring. Although optimal management with newer agents and CGM can prevent complications, some technologic advances with the potential to provide immediate improvements in quality of life for patients with diabetes has flown under the radar.

Spinal cord stimulation has been examined for decades, but, recently, new trials have drummed up interest in the approach for the management of diabetic peripheral neuropathy, including the SENZA-PDN trial. An open-label, prospective, randomized trial assessing the effects of spinal cord stimulation using a 10-kHz spinal cord stimulator from Nevro Corporation for reducing pain from diabetic peripheral neuropathy over a 12-month period, results of the study suggested use was associated with durable pain relief and quality of life improvements over the course of a year. More recently, 24-month data from an extension of the trial provided further insight into use of spinal cord stimulation for reducing diabetic peripheral neuropathy.

The 24-month results, which were presented at ADA 2022 by Erika Petersen, MD, principal investigator of the SENZA-PDN and director of Functional and Restorative Neurosurgery and Neuromodulation at the University of Arkansas for Medical Sciences, demonstrated use of the spinal cord stimulator yielded a response rate of 84%, with a 77% average reduction in pain that was consistent over 24 months. Further analysis indicated use was associated with a mean reduction in sleep disturbances of 69%, clinically meaningful improvements in quality of life, and a 71% sensory improvement rate.

To learn more about spinal cord stimulation, the 24-month results of SENZA-PDN, and real-world challenges to optimal uptake, Endocrinology Network reached out to Petersen and a portion of that conversation can be found below.

Q&A on Spinal Cord Stimulation for Peripheral Diabetic Neuropathy, with Erika Petersen, MD

Endocrinology Network: Can you describe the key take-home points from the recently presented SENZA-PDN 24-month data?

Erika Petersen, MD: One of the biggest things that worries me for patients is: How long is this going to last? A lot of people start a medication and it stops working after a few months. You know, for example, I think it's more than 70% of people who start on pregabalin aren't taking it a year later because of side effects, it stops working, or they can't afford it. The other piece that I think is really interesting is what this does when people have an illness that is potentially progressive. If somebody's blood sugar is not under control, we presume that they continue to have damage to the end organs. We see the same thing with diabetic peripheral neuropathy, but if we can demonstrate something that can hold pain levels, even when somebody continues to have diabetes and continues to be at risk of having progressive injury to their nerves, that on its own is a really important finding. And that's what we showed in our 24-month data. We showed that people had dramatic improvement in pain, in quality of life, their ability to sleep and be more active. All of those things we showed at 12 months, we can now show those things are maintained at 24 months. We would expect that some of those people in the 12 additional months might potentially be at risk of worsening disease. It’s incredibly important if these results not only hold steady but continue to work while people are still dealing with the ongoing processes of diabetes.

Endocrinology Network: How does the patient population from SENZA-PDN compare to real-world populations of patients with diabetic peripheral neuropathy?

Petersen: Our BMI cutoff was 45 kg/m2 and our HbA1c requirement was to be less than 10%. So, these were fairly permissive inclusion criteria as far as somebody's health goes, but you're absolutely right that people who volunteer to participate in cutting edge medical research are sometimes more proactive, interested, and motivated to pursue something about their health than the average population.

One of the advantages of this stimulator system is that, other than having to recharge the battery wirelessly through the skin, there is not too much that a patient needs to do in order to maintain. So, I would expect that a large number of patients in real-world settings are going to be able to do as well as those in the study. There actually is a real-world study that was published last November in the Journal of Diabetes Science and Technology looking at 79 patients who were treated with [high-frequency] spinal cord stimulation in clinical practices and they showed nearly equivalent pain response for those patients as well.

So, we had greater than 80% of patients at 24 months who had at least a 54% reduction in their pain and that average pain reduction was over 74%. On top of that, a majority of patients had some neurological improvements. This is one of the first studies ever done in spinal cord stimulation that showed sensory improvements after an intervention. That was an interesting finding to me and probably the thing I'm most excited about. This study was done to study pain and function, but the sensory finding is the next step in the story and something that I think other people are going to get excited about as well.

Endocrinology Network: Do you expect the nature of the device to cause hesitancy in some patients and how would you approach this hesitancy in a real-world setting?

Petersen: I completely agree. For a lot of people with diabetes, this may be one of the first procedures or surgeries they've ever considered. As a neurosurgeon, I do deep brain stimulation and I've had a few patients whose first operation ever is to have a brain stimulator placed, which is a pacemaker in the brain essentially, and I'm like "Wow, you went big on this one for your first operation," but everybody makes their own choices about what is at stake and what results they think they're going to get.

When you look back 3 or 4 years ago, people weren't as amenable to the idea of continuous glucose monitoring and having the ability to have an app with constant connectedness and awareness of what that number looks like all the time. So, as technology moves, people start to talk more and more about what areas are welcome to them. There are going to be some people who think this is science fiction, but there are other people who say it's a pacemaker for pain. If you can have a pacemaker in your heart, why shouldn't you have a device like this? There are a lot of devices like this, including sacral stimulators for bladder continence that are very prevalent. I think people will become more receptive because I imagine most people either use a CGM and are now familiar with technology and having something that is at the skin surface that they're interacting with for improving their control of the disease of diabetes.

Another thing is that they probably know somebody who has an implanted device—whether it's a pacemaker, a spinal stimulator, or potentially a bladder stimulator—they probably know somebody and that itself makes them more comfortable. A lot of my patients will talk to other people who've had a device. We have a network of patients who have these stimulators and are willing to talk to other patients who are thinking about having one. That approach also helps people be more comfortable with whether this is the right fit for them or not.

Ultimately, nobody really knows what it feels like to be in one's own body, besides the individual, and, if the pain and the impact in terms of quality of life is enough, then this is the next step that they will be willing to consider. The best way to approach that is with a team of clinicians who are supportive and with the resources and education that are available. The Nevro website that's for patients HFXForPDN.com does a very good job of providing some of that baseline support and information as well.