High-Frequency Spinal Cord Stimulation Eases Diabetic Neuropathy Pain

Andrew D. Bowser

June 15, 2020

For patients with painful diabetic neuropathy that doesn’t resolve with standard treatment, use of a 10-kHz spinal cord stimulation device may relieve pain and improve sensation, initial results of a large randomized controlled trial suggest.

Some 79% of patients had substantial pain relief 3 months after starting treatment, compared with 5% of patients managed with conventional medical treatment, according to results of SENZA-PDN, which investigators say is the largest-ever randomized, controlled trial of spinal cord stimulation for managing painful diabetic neuropathy.

Although this was not a comparative trial, investigator Erika Petersen, MD, said in an interview that results seen with the 10-kHz spinal cord stimulator (Nevro Corp.) exceed what has been seen in previous studies of spinal cord stimulation devices operating at lower frequencies, where response rates have been in the 40%-55% range.

New Option For Front Line Providers?

"My overall takeaway here is that these initial 3-month results are very promising," said Dr. Petersen, who is Director of Functional & Restorative Neurosurgery and Neuromodulation at the University of Arkansas for Medical Sciences in Little Rock.

Patient-perceived numbness and sensory assessments by investigators also improved following implantation of the spinal cord stimulator, according to Dr. Peterson, who added that measurements of sleep and activity also seemed to improve in these patients with painful diabetic neuropathy.

"Spinal cord stimulation has been established for chronic back and leg pain, but being able to innovate in this population with diabetic neuropathy is really something that we anticipate will improve quality of life and functional benefit for a large number of patients who currently have been stuck with the options that are currently available," Dr. Petersen said in an interview.

Natalie H. Strand, MD, assistant professor of pain medicine at Mayo Clinic, Scottsdale, Ariz., said that while the findings of this randomized study may require corroboration, they do suggest that this neuromodulation device may provide another option for front line diabetes providers when patients have persistent pain despite appropriately medication management.

"These patients are probably under-referred to interventional pain specialists," said Dr. Strand in an interview. "The primary care physicians and endocrinologists may not think of neuromodulation as an appropriate treatment, and they may not know that it can be so effective."

"Anything that we can add as physicians to help decrease the burden of diabetes is going to be very impactful," Dr. Strand added. "While this is focused on pain, what we’re really trying to treat is the entire patient – improve their quality of life and make diabetes more manageable."

Nearly 80% of Treated Patients Responded at 3 Months

The SENZA-PDN study results were presented as a late-breaking poster presentation at the virtual annual scientific sessions of the American Diabetes Association. Those results included 103 patients randomized to conventional medical management alone, and 113 who received medical management plus the spinal cord stimulator, which Dr. Strand described as a minimally invasive, reversibly implanted epidural device designed to stimulate the spinal cord and reverse pain sensations.

The median age was about 61 years and roughly two-thirds were male. All patients had to have lower extremity pain with an average intensity of at least 5 out of 10 cm on the visual analog scale (VAS) at enrollment, according to published inclusion criteria for the study (NCT03228420).

Three months after device implantation, 75 out of 95 evaluable patients (79%) had a response, defined as 50% or greater pain relief plus no worsening of neurological deficit related to painful diabetic neuropathy. By contrast, only 5 of 94 medically managed patients (5%) met those response criteria (P < 0.001), according to reported data.

The mean VAS score in the device group dropped from 7.6 at baseline to 2.4 at 1 month and 1.7 at 3 months, data show. In the medical management group, mean VAS scores were 7.0 at baseline, 6.7 at 1 month, and 6.5 at 3 months.

Sensory assessment of monofilament and pinprick perception, performed by investigators at 3 months, indicated a 72% improvement in the device arm versus 7% improvement in the medical management arm, while analysis of patient-drawn diagrams additionally suggested improvement in perceived numbness, according to investigators.

Quality-of-life improvements related to sleep and activity were also apparent at 3 months in the device group, Dr. Petersen said, with investigators noting substantial reductions in trouble falling asleep because of pain and awakening due to pain. Likewise, data at this initial report suggested improvements in 6-minute walk test that were apparent in the device group but not the medical management group.

While the spinal cord stimulator under investigation is already approved by the U.S. Food and Drug Administration, Dr. Petersen said a lack of data specific to painful diabetic neuropathy has been a hurdle to insurance coverage for some patients.

"I've had patients who clearly have every suggestion that they match the characteristics of our research population here, but the insurance will decline the procedure as being experimental," she said. "My hope is that randomized, controlled trial results in a research study such as this is something that will improve the access of the therapy to patients who would not be able to afford it without having insurance cover the procedure."

Follow-up of the study will continue for 24 months and will include assessment of health economics and use of pain medication, Dr. Petersen said.

The SENZA-PDN study is funded by Nevro Corp. Dr. Petersen said that she receives research funding and consulting fees from Nevro Corp. and other device manufacturers. Dr. Strand said she had no disclosures related to the research.

SOURCE: Petersen E. ADA 2020, Late-breaking poster 31-LB.

This article originally appeared on MDedge.com.


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