Nevro Study on Painful Diabetic Neuropathy and Spinal Cord Stimulation

The World Health Organization estimates that there are more than 422 million adults with diabetes around the world, and this is double the number just four decades ago.  Almost one in five of these diabetics will develop painful diabetic neuropathy or PDN. Painful diabetic neuropathy is a potentially debilitating pain condition that may progress if the diabetes is poorly managed.

There is good news for PDN sufferers, however. A new therapy developed by Nevro may provide some relief from pain symptoms related to painful diabetic neuropathy. The new therapy is a 10 kHz spinal cord stimulation device that has produced promising results in studies and recently earned approval from the Food and Drug Administration.

Painful Diabetic Neuropathy

Painful diabetic neuropathy is a health condition that is believed to arise from high levels of sugar in the blood damaging nerves. This damage interferes with the nerves’ ability to send signals accurately and is likely the cause of the pain symptoms associated with painful diabetic neuropathy. This condition is more likely to develop the longer the diabetes is left untreated or poorly managed.

The primary treatment for painful diabetic neuropathy now is slowing progression of the diabetes. By lowering the amount of blood sugar, the damage to the neurons can be minimized. This may be accomplished by a combination of the following:

  • Limiting sugar intake
  • Exercise regularly
  • Manage stress
  • Take medications

It can be possible to seriously lower your risk of developing painful diabetic neuropathy by keeping your blood sugar within recommended levels.

The other treatment option is to mitigate pain symptoms. Many PDN patients take anti-seizure drugs like gabapentin or antidepressants like amitriptyline or imipramine to manage their pain symptoms.

Senza System for Painful Diabetic Neuropathy

In July of 2021, the Nevro Corporation announced that it had received approval for its Senza System which treats painful diabetic neuropathy. This is currently the only spinal cord stimulation therapy for painful diabetic neuropathy approved by the U.S. Food and Drug Administration.

Spinal cord stimulation involves the implantation of an electrical device that sends electrical impulses to the spine. This low-level current blocks pain signals by occupying the spinal nerves with this stimulation.

Any spinal cord stimulation therapy involves two procedures. The first is a trial procedure that confirms that the patient will respond to electrical stimulation. The second procedure involves implantation of the permanent device.

The Senza System can deliver electrical signals with frequencies ranging from 2 Hz to 10 kHz. However, the Senza System does not deliver a constant current, but instead employs a programmer unit that sends waveforms in a variety of frequencies designed by an HF10 algorithm. This programming capability allows the physician to modify the waveform algorithm as circumstances merit.

The implant device has an upgradeable pulse generator that has a lifetime of more than ten years. The system also has conditional full-body MRI-approval, or in other words would enable patients to undergo a magnetic resonance imaging exam without removal of the implant.

Efficacy of the Senza System

Although the Senza System is not successful with all painful diabetic neuropathy patients, the results of one major study were sufficient to merit FDA approval. This study published in JAMA Neurology had 216 randomized painful diabetic neuropathy patients. The median duration of diabetes was 10.9 years, while the median duration of painful diabetic neuropathy was 5.6 years.

The study participants were enrolled from various medical facilities around the U.S. from August 2017 to August 2019. All had the 10 kHz Senza System device implanted. Various metrics including pain VAS, health-related quality of life, and HbA1C were recorded prior to device implantation and 6 months after the procedure.  A control group of painful diabetic neuropathy patients on conventional therapies was used to contrast the study participants.

Spinal cord stimulation has been used in PDN patients before but with less positive outcomes. One study published in 1996 that had 36 to 60 participants used 40 to 60 Hz SCS. This study followed up at the 6-month and 24-month periods. Researchers discovered that this low-frequency spinal cord stimulation produced uncomfortable side effects like paresthesia, i.e., burning or tingling sensations, causing many of the study participants to discontinue use.

The results from the 10 kHz SCS were considerably better than for the low-frequency SCS studies. Various metrics including lower limb motor function, light touch sensation and motor reflexes were assessed. The primary metric of pain relief was dramatically improved in most study participants. Of the 104 PDN patients that completed the test implant procedure, 90 went on to have the full and permanent 10 kHz SCS device implanted.

At the 6-month mark, the control group experienced no decline in pain intensity, but the implanted group reported a 76 percent average decline in pain scores. The implanted group had an average pain VAS score of 7.6 prior to the procedure and 1.7 score at the 6-month mark. What is remarkable is that 55 of the 88 participants in the implanted group experienced complete remission of their chronic pain condition.

It should be noted, however, that there were some flaws in the study. Because of the serious implications of implanting a medical device, the study administrators could not use a blind control group with placebo implants. This means that patient bias could have been present and unaccounted for in the trial; in other words, patients that underwent the spinal cord stimulator procedure may have unconsciously expected pain relief and skewed the study’s outcomes.

Should You Consider the Senza System?

Given the startling outcomes of this initial study, if you are a painful diabetic neuropathy patient, then it is probably in your best interest to at least discuss it with your pain specialist. You should keep in mind that there is still ongoing study into the long-term efficacy of the Senza System, and that this is a relatively serious procedure (although minimally invasive) that does carry some noteworthy health risks.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

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