Brain Implants Give Relief to Neuropathic Pain

In this image, DBS probes are attached to the top of the skull.

A medical device implanted in the brain that is used to treated depression and Parkinson’s disease is also effective at treating neuropathic pain, according to a study in Neurosurgery, the official journal of the Congress of Neurological Surgeons.

Deep brain stimulation (DBS) involves the implantation of a small electrode — sometimes called a “brain pacemaker” — which sends small electrical impulses to specific parts of the brain

Researchers at the University of Oxford gave DBS treatments to 85 patients with chronic neuropathic pain and said they achieved significant and lasting benefits in pain relief, quality of life, and overall health. Some patients continued to show improvement after the first year.

Millions of Americans suffer from neuropathy, including about half of all diabetics. Damaged or diseased nerves cause chronic pain or loss of feeling in the toes, feet, legs, hands and arms. Strokes and amputation that causes phantom limb pain can also cause neuropathy.

Stroke was the most common cause of neuropathic pain in the Oxford study, followed by head and facial pain, spinal disease, amputation, and injury to nerves from the upper spinal cord (brachial plexus).

A DBS stimulator made by Medtronic

A DBS stimulator made by Medtronic

In 74 of the patients, a trial of DBS produced sufficient pain relief to proceed with implantation of a brain pacemaker. Two-thirds of those who received the implant had significant improvement in their overall health up to four years later, including 89% of the amputees and 70% of the stroke patients.

On average, scores on a 10-point pain scale (with 10 indicating the most severe pain) decreased from about 8 to 4 within the first three months of DBS treatment.

Neuropathic pain is difficult to treat and drugs often don’t provide much relief. DBS has been approved in the U.K. to treat neuropathy, but not in the U.S.

Deep brain stimulation has long been regarded as potentially useful for patients with severe neuropathic pain. However, there has been relatively little research to confirm its benefits; only 1,500 patients have been treated worldwide. The new study —  accounting for about five percent of all reported patients — used updated DBS technologies, imaging, and surgical techniques.

Oxford researchers say larger studies are needed to confirm their findings.