Preliminary 6-month results from the first-in-human trial of deep brain stimulation (DBS) of the subgenual singulate cortex (SCC) for chronic low back pain, suggested that the procedure reduces pain, opioid use, and disability. In addition, the procedure was well tolerated with no serious adverse events or complications.
"We believe DBS is an option for those patients with severe low back pain who have tried and exhausted medications, physical therapy, and a trial of spinal cord stimulation," principal investigator Ausaf A. Bari, MD, PhD, University of California, Los Angeles, told Medscape Medical News.
The findings from the first treated patient were presented on May 4, 2024, at the American Association of Neurological Surgeons 2024 Annual Meeting.
A New Treatment Target?
"There's a growing amount of scientific evidence including neuroimaging that pain, in general, and chronic low back pain, in particular, affects brain circuits," Bari noted.
Therapies such as spinal cord stimulation (SCS) don't address these brain changes, he added, which could explain why SCS seems ineffective for low back pain.
"Our hypothesis is that DBS will help these patients by modulating brain circuits that mediate chronic pain," Bari said.
These brain circuits have known connections to the SCC, so the researchers propose it may serve as a target for DBS to control chronic low back pain.
The patient was a 50-year-old male with a history of medically refractory chronic low back pain for > 20 years and failed back surgery syndrome, who had failed a trial spinal cord stimulation and was taking 10 mg oxycodone three times a day.
He underwent stereotactic implantation of bilateral SCC DBS electrodes and placement of an implantable pulse generator. Probabilistic tractography was used to target the SCC region with connectivity to a combination of participant-specific white matter fibers associated with affective neural networks. Stimulation-related side effects were ruled out using awake intraoperative testing.
At a 6-month follow up, the patient's pain levels had decreased significantly from baseline, including a 75% drop on the Visual Analog Scale and an 86% drop on the Pain Anxiety Symptom Scale. In addition, there was a 90% decrease in the Oswestry Disability Index score.
Weekly opioid doses and oral morphine equivalents were also reduced by 95%, Bari reported.
Bari said the trial defined nonsurgical pain as low back pain that does not have a surgically addressable cause and has been deemed to be nonoperative by two surgeons. Investigators plan to enroll a total of 15 patients in the phase 1 study.
"We need more clinical trials of DBS that can test the most promising brain areas," said Bari. "This will require multisite clinical trials and cooperation between multiple centers and disciplines."
Generalizability Challenging?
Commenting on the research for Medscape Medical News, Michael Staudt, MD, MSc, University Hospitals Cleveland Medical Center, Ohio, who was not involved in the study, said one of the challenges is that the definition of nonsurgical back pain can vary widely between surgeons, payers, and interventionalists.
"So, when we say nonsurgical back pain, we're already putting [patients] into a category that's a little bit muddy," Staudt said.
He also noted that recent, large trials cleared by the US Food and Drug Administration are using spinal cord stimulation for nonsurgical back pain because it is low impact and offers another nonsurgical option for people who fail medical management.
"The step between spinal stimulation and deep brain stimulation is a big step," Staudt said. "It's not brain surgery to do a spinal cord stimulator. You won't find many people who are putting in deep brain stimulators, and the challenge with that is it's hard to say if you'd get enough patients in a large enough trial to show overall benefits and cost effectiveness."
"I do find it very interesting," Staudt added. "He's [Bari] published it and worked on it for a long time, but the applicability, the generalizability is challenging."
The study was funded by the National Institutes of Health. Bari reported serving as a consultant for Medtronic and Novartis and on the scientific advisory boards of Nervonik and Vonova. Co-investigator Nader Pouratian, MD, PhD, reported consulting for Abbott Laboratories and Sensoria Therapeutics. Staudt reported serving as a consultant for Abbott and a scientific advisor and consultant for Boston Scientific.
Patrice Wendling is a medical journalist based in Chicago.
Note: This article originally appeared on Medscape
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