Every 20 seconds, Greg Dubrule receives a short, high-frequency electrical pulse to the epidural space in his spinal cord from a small, wired device implanted in his back a year ago.

“For me, full power is the setting that works best,” the 66-year-old Groton resident, owner of the Black Hawk sport fishing boat in Niantic, said last week, explaining how he controls the level and rhythm of the pulses. “It’s been heaven-sent. It’s not that I can do any more or less than I used to, but I can live relatively pain-free.”

Since 1993, Dubrule had been in constant pain from injuring his back during a fishing tournament. After three surgeries and multiple medications brought little relief, he agreed to have a new type of spinal cord stimulator implanted first on a trial basis, then permanently. Costing $20,000 to $25,000, the device and surgery were covered by workmen's compansation insurance, he said.

“I probably have at least 60 percent less pain,” he said. “Being out on the water, you get bounced around a lot, so that’s a good test of the stimulator working.”

Dubrule is one of about 40 local residents turning to the latest version of a technology that’s been around for 30 years as an alternative to surgery and to avoid the dangers of highly addictive opioid painkillers. The devices, made by the Nevro Corp. of Redwood City, Calif., and approved by the Food and Drug Administration in 2015, administer 10,000 hertz of electricity for a minute fraction of a second at low amplitudes to disrupt the body’s pain signals, all but replacing older stimulators that used low-frequency, longer-duration pulses.

“This is a very good alternative for people in chronic pain, especially given the opioid addiction crisis,” said Dr. Sudhir Kadian of the Shoreline Interventional Pain Center in New London, He has implanted about 20 of the devices since 2016, while his partner in the practice, Dr. Honghui Feng, has implanted another 20. During the two- to three-hour "minimallly invasive" surgical procedure, which is used for the permanent implant, wire leads with electrical contacts at the end are threaded along the spinal cord to discs T8 and T9, roughly the midpoint of the back.

"This is the sweet spot," Kadian said. 

Dr. Tim Lamer, a spine and pain specialist at the Mayo Clinic in Rochester, Minn., believes many more patients could benefit from the high-frequency stimulators, which mainly relieve low back and leg pain. Lamar, who serves on the executive board of the American Academy of Pain Medicine, said the new devices are providing greater relief with fewer side effects like the leg tingling and numbness the lower-frequency versions were known for. Nationally, about 15,000 of the high-frequency devices are now in use, according to the company.

“We’re seeing success in 70 to 75 percent of patients,” he said, adding that the device is considered successful if it relieves 50 percent or more of a patient’s pain. “Ten years ago, we didn’t have anything for them. What this device does is activate your body’s intrinsic pain relief system, increasing serotonin. It blocks or suppresses the pain signals. The data for this has the best outcomes of anything else we’ve done.”

In a November article in the journal Neurosurgery, researchers compared the effectiveness of high- to low-frequency stimulators among patients at 11 pain treatment centers across the country. After three months, about 84 percent of patients with the new device reported experiencing 50 percent or more reduction in their pain. By comparison, only about half of the patients with the low-frequency stimulators saw that much pain relief, according to the study, which is slated to continue for the next two years.

Lamar cautioned, however, that the device isn’t for everyone in pain. Patients must undergo careful screening, including psychological testing to rule out untreated mental health conditions, and have tried several types of more conservative therapies first. These include steroids, physical therapy and anti-inflammatory medication.

“For properly selected patients, the results are very good,” he said.

Laura Cross of Gales Ferry, a labor and delivery nurse at Lawrence + Memorial Hospital, last week completed a one-week trial with a Nevro stimulator, and is deciding whether to have the permanent device. The intractable back pain she’s lived with for the last nine years was about half as severe as without the stimulator, she said.

“I thought it would do more than it did,” she said. “But I was in a better mood with less pain. I’ll probably do it, but I’ll have to think about it.”

Another L+M nurse, Debbie Scott, 62, can’t wait to get the permanent device, based on her recent pain-free week using the temporary one.

“It was life-changing,” the Waterford resident said. “I could actually sit up for a while and cook.”

Now, she said, she’s awaiting word from her insurance company about whether it will approve coverage of the permanent implant.

Sixty-seven-year-old Bernard Nasser of Groton, a retired high school teacher, wrestling coach and former marathon runner, called his recent week using the trial stimulator “awesome.” He tried steroid injections and ablations without success, and considered spinal fusion therapy, but decided that was too risky. Like many other patients, he is adamant about avoiding opioid medications. Now that he’s tried the simulator, he has hope he can get back to gardening and long walks one day, provided his insurance company approves coverage.

“I’ve been in a lot of pain the last four years, and this gave me incredible relief,” he said. “I had about 75 percent less pain. I moved around a lot more.”

 j.benson@theday.com