Spinal Cord Stimulation Eases Pain From Diabetic Nerve Damage, Trial Finds

A multicenter randomized clinical trial led by researchers at Wake Forest University School of Medicine found that high-frequency spinal cord stimulation significantly reduced pain and improved sensory function in people with treatment-resistant painful diabetic neuropathy. The findings, published in the journal Diabetes Care, also showed early evidence of increased density of small nerve fibers in the skin, though the researchers said more work is needed to understand whether that effect persists.

Diabetic neuropathy is a common complication of diabetes that can cause chronic pain, numbness and loss of feeling, particularly in the feet and legs, and as it progresses can lead to balance problems, foot ulcers and a higher risk of amputation. Current treatments mainly manage symptoms and do not reliably restore sensation or reverse nerve damage. The study, called the Painful Diabetic Neuropathy Sensory study, tested 10-kHz spinal cord stimulation, in which thin leads are surgically implanted near the spinal cord along with a small pulse generator under the skin, sending mild electrical pulses that alter how pain signals travel to the brain.

The trial enrolled 91 adults with diabetes and chronic, treatment-resistant painful diabetic neuropathy at 13 centers across the United States, randomly assigning them to receive either conventional medical management alone or spinal cord stimulation plus conventional medical management. Using a conservative analysis that accounted for missing outcomes, 79.4% of participants who underwent temporary spinal cord stimulation achieved at least a 50% reduction in lower-limb pain, compared with 4% of those receiving conventional medical management alone; among participants who received a permanent implant and completed six-month follow-up, 93.1% achieved that level of pain reduction.

The trial also met its sensory endpoint: among participants who completed six-month follow-up, 55.2% of those receiving spinal cord stimulation showed meaningful improvement in their ability to detect touch, temperature, vibration and body position, compared with 25% of those receiving conventional medical management. Skin biopsies showed an average 56% increase in small nerve-fiber density in the lower calf among participants receiving spinal cord stimulation, with no significant change in the conventional-treatment group, though the study was not designed to determine whether the nerve fibers had regenerated.

"Pain relief was expected based on previous research, but the objective improvements in sensory measures and nerve-fiber density were particularly encouraging," said Robert W. Hurley, the study's corresponding author and a professor of pain medicine and anesthesiology at Wake Forest University School of Medicine. He said longer follow-up is needed to determine whether the changes persist and what they mean for patients. The researchers noted the trial was stopped early after meeting its effectiveness criteria, which can make a treatment effect appear larger, and that participants had severe, treatment-resistant neuropathy, so the findings may not apply to people with milder disease.