NEW YORK (Reuters Health) - High-frequency (10 kHz) spinal cord stimulation (SCS) provides durable pain relief in patients with painful diabetic neuropathy (PDN) who don't respond to conventional medical therapy, according to 12-month results from the SENZA-PDN study.
The findings, online now in Diabetes Care, support the six-month results published earlier this year in JAMA Neurology.
The SENZA-PDN study enrolled 216 patients with refractory PDN, with 103 patients randomly assigned to conventional medical management (CMM) alone and 113 to CMM plus the Senza System with 10-kHz SCS made by Nevro Corporation, which funded the study. The U.S. Food and Drug Administration (FDA) approved the system to treat PDN last summer.
At six months, patients had the option to crossover to the alternative treatment if they continued to have insufficient pain relief. In the CMM group, 95 completed six-month follow-up and 81% (77 of 95) chose to crossover to 10-kHz SCS compared with none from the 10-kHz SCS plus CMM group.
Mean lower limb pain on the 10-cm visual analog scale (VAS) was 7.6 cm for the SCS patients at baseline, dropped significantly to 1.7 cm at six months and remained at 1.7 cm at 12 months. This represented 77.1% mean pain relief (P<0.001), with 86% of patients responding to treatment, report Dr. Erika Petersen of the University of Arkansas Medical School and colleagues.
For the crossover group, mean baseline lower limb pain VAS score was 7.2 cm, with no change at six months but improvement after crossover to SCS, similar to the originally assigned 10-kHz SCS group: mean 70.3% pain relief (P<0.001), with lower limb pain VAS score of 2.0 cm, and 84% responders, they report.
Neurological improvements, particularly improved sensory function, maintained over 12 months for the majority of patients receiving 10-kHz SCS, including 68% of patients originally assigned to SCS and 62% who crossed over to SCS.
There were eight infections related to the implant procedure (5.2%). Three resolved with conservative treatments, while five (3.2%) required removal of the device.
"There were no explants for loss of efficacy. Two participants (1.3%) had the location of the implantable pulse generator revised, and one participant (0.6%) experienced lead migration that required a revision procedure; all three continued in the study," the researchers report.
"Patients with painful diabetic neuropathy have no way to cure their condition, and many have trouble achieving relief from their pain," Dr. Petersen said in a news release.
"However, with high-frequency 10 kHz therapy, I'm seeing durable pain relief and potentially disease-modifying neurological improvements, which could be a game-changer when it comes to how we treat patients with impaired sensory function," she added.
Two companion papers in the Journal of Diabetes Science and Technology provide real-world evidence of pain relief and functional improvements with Nevro's 10 kHz SCS device.
In their paper, Dr. Jeffrey Chen of the University of California, San Diego, and colleagues report that 58 of 73 patients using the device (79.5%) responded to treatment, having at least 50% patient-reported pain relief from baseline. Average follow-up in the patients, who were mostly older men, was 21.8 months. Most patients also reported improvements in sleep and overall function relative to baseline.
In the other paper, Dr. Natalie Strand of Mayo Clinic Arizona, in Phoenix, and Dr. Adam Burkey of Anesis Spine & Pain Care, in Renton, Washington, review the current evidence for both high-frequency and low-frequency SCS to treat PDN, finding that high-frequency 10 kHz SCS provides greater pain relief and improves neurological function.
In email to Reuters Health, Dr. Petersen said, "There have been several well-designed studies published on pharmacological treatments for PDN; unfortunately, the pain relief shown is often modest and many patients do not tolerate the side effects of these medications. This patient population is in need of better treatment options."
"Candidates for high-frequency (10 kHz) SCS are people with diabetes who have burning or stabbing pain in their feet that is often worse at night and who have not had relief with medications. Patients should be healthy enough to undergo a minimal risk surgery to implant the SCS device," Dr. Petersen said.
"There are likely millions of people in the US who could benefit from high-frequency SCS, now approved by the FDA for treatment of PDN," she added.
Support for all three studies was provided by Nevro Corp. Several authors have disclosed financial relationships with the company.
SOURCES: https://bit.ly/3prxCIP, https://bit.ly/3GdkJZD and https://bit.ly/31pWjxe Diabetes Care, Journal of Diabetes Science and Technology, online November 29, 2021.
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