FDA Approves Device That Uses Artificial Intelligence to Treat Chronic Pain

By Pat Anson, PNN Editor

The Nevro Corporation says it has won approval from the Food and Drug Administration for an advanced spinal cord stimulator (SCS) that uses artificial intelligence to individualize treatment for each patient.

Nevro says its Senza HFX iQ stimulator “learns from patients” as they use the device and develops customized algorithms for treating chronic back pain, leg pain and pain from diabetic neuropathy.

"HFX iQ is designed to improve the consistency of pain relief and is the only SCS system that truly personalizes care," D. Keith Grossman, Chair and CEO of Nevro, said in news release.

"Pain is variable from patient to patient and over time. Using the big data from our HFX Cloud patient database, our unique HFX Algorithm was developed to identify those programs where patients have been more likely to get relief in the real world.  HFX iQ takes direct input from each patient on their pain and quality of life measures to get smarter over time and recommend program changes.”

Nevro says patients will start with a program most likely to provide pain relief, and then adjusts it over time based on patient input and medical data, such as pain scores, activity levels and changes in use of pain medication. Patients can also adjust their pain relief programs through an app on their smartphones.

Spinal cord stimulators are usually considered the treatment of last resort for people with intractable or severe chronic pain that doesn’t respond to other therapies. The surgically implanted devices emit low levels of electricity that reduce the intensity of pain signals.

Unlike older stimulators, Senza stimulators use electric pulses of 10 kHz, a high frequency that doesn’t create an uncomfortable tingling sensation and delivers more pain relief. Last year the FDA approved Senza stimulators for the treatment of painful diabetic neuropathy, making it the first spinal cord stimulation system approved for that condition. Until then, most SCS devices were only approved for patients with severe back pain.

About 50,000 stimulators are implanted in the U.S. every year, with failure rates for the devices estimated at 25 to 30 percent. Most patients are required to undergo psychological testing and a trial treatment before getting a SCS.

The FDA has come under scrutiny for its regulation of stimulators and other medical devices.  A 2020 report by Public Citizen accused the FDA of “dangerously lax” oversight of stimulators, which were linked to 156,000 injuries and 931 deaths.  The agency responded to the report by sending a letter to healthcare providers reminding them to only implant stimulators after a trial period that demonstrates the device are effective. An FDA review of adverse events involving stimulators found that nearly a third were reports of unsatisfactory pain relief.

Nevro says it will begin a limited release of Senza HFX iQ later this year, with a full market launch in the U.S. in early 2023. Nevro is also seeking approval of HFX iQ in Europe.  

FDA Approves Spinal Cord Stimulator for Diabetic Neuropathy

By Pat Anson, PNN Editor

Like many other people with diabetic neuropathy, Lee Cagle suffered from burning and stinging sensations in his legs – pain so severe that he used sheets at night to build a small tent around his feet so that the fabric didn’t touch his skin and trigger another flare.

The 33-year-old Arkansas man tried pain medications such as hydrocodone and gabapentin (Neurontin), but didn’t like their side effects or potential for addiction.

“I don’t want to get hooked on pain meds. I’ve seen people hooked on pain meds and I didn’t want that for myself,” Cagle told PNN. “I only used them on the worst of worse days, when I could not fall asleep because I was in so much pain.”

Last year Cagle heard about a clinical trial for people with painful diabetic neuropathy (PDN) and decided to take a chance, enrolling in the study to see if a Nevro spinal cord stimulator could relieve his pain. The device emits mild electrical pulses to disrupt pain signals before they reach the brain. 

“It was almost instantaneous. The ease of the pain that it gave me,” Cagle said. “I felt so much better.”

The results from his two-week trial were so promising that Cagle agreed to have the stimulator permanently implanted along his spine during an outpatient procedure. That was nine months ago.

“I’m a completely different person now, compared to what I was before I got it put in my back,” said Cagle, who had only one minor setback when one of the electrodes leading from the stimulator failed.      

Cagle was one of 113 patients with PDN who had Nevro stimulators implanted during the clinical trial. Several dropped out of the study due to adverse events such as infections and two had their devices removed.

Most of those who remained reported significant pain relief of at least 50% and improved quality of life.

NEVRO IMAGE

The overall results were so promising that the Food and Drug Administration recently approved Nevro’s Senza stimulators for the treatment of PDN, making it the only spinal cord stimulation system approved for that condition. The Senza stimulators are unique because they use high frequency electric pulses of 10 kHz, a frequency that doesn’t create an uncomfortable tingling sensation that’s common with other stimulators.

"The substantial pain relief and improved quality of life demonstrates that 10 kHz Therapy can safely and effectively treat this patient population," said lead investigator Dr. Erika Petersen, Professor of Neurosurgery and Director of Functional and Restorative Neurosurgery at the University of Arkansas for Medical Sciences. "I'm grateful to my co-investigators and the patients who participated in this study, as the results and this approval will have far-reaching impact on the lives of PDN patients."

‘Dangerously Lax’ Oversight

FDA approval of the Nevro stimulator for PDN is a significant expansion of the medical device market. Of the 34 million Americans with diabetes, about one in five have painful neuropathy, a condition that develops when high blood glucose levels damage peripheral nerves. Until now, most spinal cord stimulators were only approved for patients with severe back pain.

FDA approval also comes at a time when the agency is under growing scrutiny for its regulation of medical devices, particularly spinal cord stimulators. A 2020 report by Public Citizen accused the FDA of “dangerously lax” oversight of stimulators, which were linked to 156,000 injuries and 931 deaths. Ironically, the report noted that spinal cord stimulators are often touted as safer alternatives to opioid medication.  

“In the midst of the opioid crisis, medical device companies and medical centers that implant spinal cord stimulators increasingly have been marketing spinal cord stimulation as an alternative to opioids for chronic pain,” the report found. “Importantly, no evidence was provided that spinal cord stimulators reduce the use of opioids.”  

The FDA responded to the Public Citizen report by sending a letter to healthcare providers reminding physicians to only implant stimulators after a trial period that demonstrates the device provides effective pain relief. An FDA review of adverse events involving spinal cord stimulators found that nearly a third were reports of unsatisfactory pain relief. Even worse, the review identified nearly 500 deaths linked to the devices between 2016 and 2020.

A new study published this week in JAMA Internal Medicine concluded that the FDA’s adverse events reporting system for medical devices may significantly underestimate the number of deaths that actually occur. Researchers found the system relies too heavily on adverse events reported by device manufacturers.

The Center for Medicare Services (CMS) is also taking a harder look at spinal cord stimulators. On July 1, CMS implemented a new rule requiring Medicare patients to get prior authorization before a stimulator is implanted. The agency said there has been significant expansion in the use of spinal cord stimulators – about 50,000 are now implanted every year in the U.S. – but it could find no medical reason to justify the increasing number of procedures.

“After reviewing all available data, we found no evidence suggesting other plausible reasons for the increases, which we believe means financial motivation is the most likely cause," CMS said.

Industry groups and some members of Congress lobbied hard against the CMS rule, saying prior authorization would create “significant barriers to access to medically necessary procedures.”    

For patients who are desperate for pain relief, who find medication ineffective or difficult to obtain, spinal cord stimulation may be one of the few options remaining. Asked if he would recommend the Nevro stimulator to other DPN patients, Lee Cagle said he would.

“Definitely. Most definitely. I’m a totally different person now,” he said. “If Nevro came in with something else, if they needed me for a trial study, I wouldn’t hesitate.”  

Senza Stimulator Rated More Effective Long Term

By Pat Anson, Editor

A two-year study of an innovative spinal cord stimulator shows the device is more effective at relieving chronic back and leg pain long term than traditional stimulators.

The Senza HF10 spinal cord stimulator uses high frequency pulses of 10,000 Hz to mask a patient’s perception of pain. Traditional stimulators typically use lower frequencies at 40 to 60 Hz.  

Spinal cord stimulators (SCS) are often considered the treatment of last resort for chronic back and leg pain, because the devices have to be surgically placed near the spine and connected to batteries implanted under the skin. The devices send electrical impulses into the spine to mask pain.

In a study of 171 patients with implanted SCS devices, 76% of those with back pain and 73% with leg pain had pain relief after 24 months with the Senza HF10. That compares to about 50% of the patients implanted with a traditional stimulator.

image courtesy nevro

The Senza stimulator is made by Nevro Corp. (NYSE: NVRO) a medical device company in Redwood City, California.

"By demonstrating a significant and durable decrease in back and leg pain over a two-year period, Nevro's HF10 therapy represents an important and evidence-based advance in pain medicine,” said Leo Kapural, MD, the lead author and principal investigator of the study, which is published in the journal Neurosurgery.  

“Extending comparative safety and efficacy outcomes from 12 to 24 months provides physicians, patients, and payers with rigorous evidence demonstrating the durability of SCS in treating chronic pain.”

The Senza SCS was approved by the Food and Drug Administration last year. It has been available in Europe and Australia for several years.

Nevro says the HF10 stimulator is the only SCS therapy that provides pain relief without paresthesia -- a tingling or buzzing sensation that lower-frequency stimulators use to help mask pain signals. Some patients have found paresthesia uncomfortable.

MarketsandMarkets, a market research firm based in Dallas, estimates the global market for spinal cord stimulators and other neuromodulation devices could reach $6.8 billion by 2017.

New Stimulator Delivers Back Pain Relief

By Pat Anson, Editor

A new type of spinal cord stimulator (SCS) provides significantly more relief from chronic back and leg pain than traditional SCS therapy, according to the results of a new study published in the journal Anesthesiology.

The Senza spinal cord stimulator, which recently won approval from the U.S. Food and Drug Administration, uses high frequency pulses of 10,000 Hz to mask a patient’s perception of pain. Traditional SCS therapies use frequencies of 40 to 60 Hz.

"This is the first long-term study to compare the safety and effectiveness of high frequency and traditional SCS therapy for back and leg pain," said lead author Leonardo Kapural, MD, professor of anesthesiology at Wake Forest University School of Medicine and clinical director at the Carolinas Pain Institute.

"Chronic back and leg pain have long been considered difficult to treat and current pain relief options such as opioids have limited effectiveness and commonly known side effects. Given the prevalence of chronic pain, high frequency SCS is an exciting advance for our patients."

image courtesy of nevro

In a study of 171 patients with implanted SCS devices, 85 percent of those with back pain and 83 percent with leg pain using the Senza HF10 stimulator had a 50% reduction in pain or greater after three months.

Only about half the patients implanted with a traditional SCS device (44% with back pain and 56% with leg pain) experienced that kind of pain relief.

None of the patients in the HF10 therapy group experienced paresthesia – a tingling or buzzing sensation often felt with lower frequency stimulators. They were also more likely to be “very satisfied” with their pain relief (55% versus 32%).

Lower back pain affects about a quarter of the world’s adult population and is the leading cause of disability. Back pain is usually treated with physical therapy or pain relievers.

For chronic back pain, spinal cord stimulators are often the treatment of last resort because the devices have to be surgically placed near the spine and connected to batteries implanted under the skin. The devices send electrical impulses into the spine to mask pain.

The Senza SCS system is made by Nevro (NYSE: NVRO), a medical device company based in Menlo Park, California. Senza has been available in Europe and Australia for the last five years. In May, Senza won approval from the FDA for use in the United States.

MarketsandMarkets, a market research firm based in Dallas, estimates the global market for spinal cord stimulators and other neuromodulation devices could reach $6.8 billion by 2017.