A brand new study suggests that high-frequency spinal cord stimulation offers the most effective possible pain relief for diabetic neuropathy.

The therapy, Nevro’s HFX system, involves the surgical implantation of a small electronic device near the spine. Thin wires to the spinal cord offer “direct neural inhibition,” blocking the passage of pain signals between the extremities and the brain.

The study, published in Diabetes Research and Clinical Practice, showed that Nevro’s system boasts unmatched efficacy for painful diabetic neuropathy, a condition that’s notoriously proof against medical treatment. After 24 months, the overwhelming majority of participants reported significant and sturdy pain relief. Talking to Diabetes Each day, David Caraway, MD, PhD, the chief medical officer of Nevro, called the outcomes “spectacular.”

“Truthfully, you don’t see results like that; 90 percent of patients had at the very least 50 percent pain relief, in a multicenter two-year trial. It just doesn’t really occur.”

The spinal cord stimulation treatment also produced intriguing knock-on effects. In a post-hoc evaluation, study participants using the HFX system were found to enjoy each weight reduction and higher blood sugar control (A1C). The therapy also appeared to enhance sensory and neurological function. This unanticipated bonus must be evaluated in more-focused trials, but it surely suggests that high-frequency spinal cord stimulation is just not merely masking pain but in addition addressing peripheral neuropathy in a more profound manner.

Painful Diabetic Neuropathy

Neuropathy is a variety of nerve damage common in individuals with diabetes, ultimately attributable to high blood sugar levels (hyperglycemia). Diabetic neuropathy can affect many parts of the body, but it surely incessantly touches the feet and legs first. This nerve damage and dysfunction may be extremely uncomfortable, with patients feeling pain, tingling, burning, or prickling; the pain is commonly worse at night.

The pain from diabetic neuropathy can be frustratingly difficult to treat. A 2014 study, for instance, found that only 14 percent of patients enjoyed significant pain reduction from gabapentin — a commonly prescribed and officially really helpful drug therapy — compared with those using a placebo.

Patients who’re in a position to find relief often use a mixture of prescription medication, over-the-counter treatments comparable to ointments, alternative remedies like cannabis, and nonmedicinal techniques comparable to massage or foot elevation. Sadly, many individuals with painful diabetic neuropathy find no relief from any of those treatments, and have resigned themselves to the discomfort and pain.

Spinal Cord Stimulation

Spinal cord stimulation involves the surgical implantation of a small device within the back. This device delivers mild electrical pulses along thin wires to the spinal cord. These pulses mask or block pain signals from reaching the brain.

The technique isn’t recent; it’s been used for years for a lot of varieties of chronic pain, comparable to failed back surgery syndrome. The stimulators typically include distant controls that allow patients to regulate the variety of pain relief they’re receiving.

In the USA, there are three spinal cord stimulation systems currently approved for the treatment of painful diabetic neuropathy. The devices made by Nevro’s two competitors, Medtronic and Abbott, emit a lower electrical frequency that largely masks pain by introducing a tingling sensation known technically as “paresthesia.” Nevro’s high-frequency device, however, doesn’t cause a tingling feeling. Several studies, of patients each with and without diabetes, have shown that high-frequency stimulation offers more-effective pain relief.

Pain Relief Results

The brand new study enrolled 216 patients with “refractory” painful diabetic neuropathy: People had already failed to answer at the very least one drug treatment. For the primary six months, the volunteers were randomly placed into two groups, one receiving the Nevro HFX device, the opposite receiving conventional care. After six months, patients were allowed to modify treatments in the event that they so desired. Patients subjectively rated their pain levels on the usual scale, selecting a number from 0 to 10. The study continued for a complete of two years:

• Nevro HFX reduced pain by a median of 80 percent.
• Ninety percent of participants experienced greater than 50 percent pain relief.
• Within the group that originally received spinal stimulation devices, none elected to modify to traditional care after six months.
• Within the group that originally received conventional care, 93 percent elected to have the Nevro device implanted.

Measures of sleep quality and quality of life similarly improved.

Five patients (3.2 percent) needed to have the implant removed as a result of infection.

Improved Sensation

The study also tested for changes within the patients’ sensory, motor, and reflex functions. The outcomes were “surprising even to us,” says Dr. Caraway.

Sixty-six percent of implanted individuals exhibited a “clinically meaningful improvement,” mostly in sensory function. Some participants offered cheerful anecdotes attesting to the change: “These patients would say things like, ‘I can feel the cold tiles on my floor for the primary time in years’ or ‘I can feel my socks again!’”

The development in sensation is, frankly, difficult to clarify. It doesn’t necessarily make any sense that spinal cord stimulation — which is meant merely to dam pain signals — would enhance the power to feel.

“We’ve got several working hypotheses,” Caraway says. For one, perhaps fast pain relief allowed people to perceive sensations that had previously been masked by pain. Some patients claimed to experience sensory improvement almost immediately, and “perhaps whenever you profoundly relieve pain, perhaps you’re in a position to process sensory information higher.”

There’s also some preliminary, unpublished evidence that high-frequency spinal stimulation helps to extend nerve fiber density. “Perhaps we’re having direct effects on pain circuit neurons?”

Nevro has launched into a brand new study that may deal with these neurological improvements. Caraway can’t wait to unravel it: “Is it true, clinically? Let’s do a fair higher study. If we are able to show improvement in sensory function, now that makes an enormous difference. We’ll know more as we progress.”

A1C and BMI

Nevro’s big study was not initially designed to judge blood sugar control or weight reduction as primary outcomes, but a post-hoc evaluation released during June’s annual American Diabetes Association (ADA) scientific conference found that certain subsections of trial participants enjoyed improvements in each measures.

An initial evaluation of the general numbers found that Nevro HFX didn’t result in blood sugar improvements. But when limited to patients with a starting A1C of greater than 8.0 percent (those not meeting traditional benchmarks for glycemic control), there was a drop of 1.0 percent after two years that was each “statistically and clinically significant.”

Participants also lost weight. After the total two years, participants had lost a median of 6.8 kilos; those with class 2 obesity lost 11.9 kilos.

It’s unlikely that the device itself caused these improvements directly.

“We don’t think it’s a direct physiological effect,” says Caraway. “It’s probably lifestyle changes. In the event you’re taking a patient’s pain away, they usually’re paying more attention to their hyperglycemia, they’re walking around more, they’re comfortable, their mood is best, they usually’re sleeping higher, you may imagine that things are going to get well by way of A1C and BMI.”

Pain relief, briefly, can result in healthier lifestyles. Caraway shared the story of 1 participant, a security guard at a significant sports arena, whose neuropathic pain affected his mobility so badly that he had resigned himself to being stuck at a desk for the remaining of his life. Now he’s walking “18,000 steps a day” and has lost about 60 kilos.

Too Good to Be True?

Some experts, nonetheless, caution against taking Nevro HFX’s results at face value. During June’s ADA conference, it became clear that specialists within the study of painful diabetic neuropathy doubted that spinal cord stimulation was quite as effective as the brand new study implied.

Eva Feldman, MD, PhD, a professor of neurology on the University of Michigan, explained her skepticism: “My concern, which is shared by many neurologists, is that this invasive procedure … has not definitively been shown to be effective beyond a placebo response.”

Dr. Feldman explained that Nevro HFX has never been tested against a placebo. A very rigorous clinical trial would implant “sham” devices in some volunteers, a measure that Nevro has never taken — and is unlikely ever to take, on condition that it has already won approval from the U.S. Food and Drug Administration. “Several clinical trials in other disorders with pain, comparable to migraine, have shown a big placebo effect,” Feldman continued.

Rob Singleton, MD, a professor of neurology on the University of Utah, speculated that the placebo effect could possibly be especially large for a therapy like spinal cord stimulation, which requires each an invasive procedure and ongoing management, much more complicated than a straightforward shot or pill. It could possibly be that the added investment predisposes patients to be especially eager for positive results.

Each experts also expressed skepticism of the claim that spinal cord stimulation could improve sensation. On the conference podium, Dr. Singleton wondered aloud whether those claims were “adequately measured.” Feldman doubted that the connection between spinal cord stimulation and improved neurological function made any sense in any respect.

Takeaway

A brand new study suggests that Nevro HFX, a high-frequency spinal cord stimulation system, offers unmatched relief from painful diabetic neuropathy for patients who don’t respond to traditional treatment. Study participants enjoyed remarkable levels of pain relief and enhanced sleep quality, and a majority even appeared to have enhanced sensation of their feet. For some, the improved quality of life translated to each weight reduction and higher blood sugar control. Some experts, nonetheless, caution that the outcomes are lower than reliable and that the therapy is probably not quite as powerful as the brand new study implies.