Medicine

Zapping the brain to bring refief from pain

Elaine Waese May 7 1979
Medicine

Zapping the brain to bring refief from pain

Elaine Waese May 7 1979

Zapping the brain to bring refief from pain

Medicine

Whenever her old arm injury kicks up, Claudette Nepton flicks on a radio transmitter, the size of a cigarette package, sending her brain a tiny zap of electricity that kills her pain. She’s one of an estimated 300 people in the world (20 in Canada) who have analgesic electronic stimulators surgically implanted in the thalamus region of their brains, the area that integrates sensory information. Before the operation, nerve damage in her right arm, resulting from a car acci-

dent, caused Mrs. Nepton such agony that, even with massive doses of morphine, she could barely do her daily chores and her neck muscles tensed so badly, she couldn’t talk. As a last resort, her doctors suggested Deep Brain Stimulation (DBS) and referred her to brain surgeon Dr. Jean-Louis Lalonde at Sacré Coeur Hospital in Montreal.

In the operating room, head shaven, she received a local anesthetic (the brain is insensitive to pain) and through a hole drilled in her skull, an electrode wire was inserted into the centre of her brain. Dr. Lalonde probed the electrode into several potential targets, stimulating each one with an elec-

tric current, until he located the spot in her brain where stimulation seemed to provide her with maximum relief; acrylic filled up the bur hole, anchoring the electrode wire that was to stick out of her head for the next couple of weeks—a trial period to determine whether or not the gadget could relieve her pain.

The trial was a success. A second operation completely internalized the rest of the equipment—the dangling wire was imbedded under the skin of her

neck, shoulder and chest, ending in a radio-frequency receiver, the size of a quarter, which sat between her breastbone and the skin of her chest. (Deep Brain Stimulators are wonders of biomedical engineering: the circuitry is so tiny, it must be assembled under a microscope; materials encasing the electronics are recently designed ceramics that won’t corrode in the body’s harsh environment; seams are closed by laser beams. With the installation ready for use, Claudette Nepton could turn on the transmitter and in 15 min-

utes or so have several hours’ relief from her pain. A year later, she reports, “For me, it was a miracle. I can do my housework now, and I can talk again—I still have pain, but I can live with it.” DBS was developed in 1971 by Dr. Yoshio Hosobuchi at the University of Cal-

ifornia Medical School. The procedure effectively relieved severe chronic pain of cancer, spinal disc degeneration, arthritis, spinal cord injury, but the question was howl The answer remains an enigma—nobody, not even the dozens of doctors using it, understands how it works: the best they can offer is a theory which suggests that since relief can last for many hours after only a few minutes of stimulation, it’s possible electrical stimulation may trigger the brain’s release of natural pain-killing chemicals.

Most doctors working with DBS are happy with their results and find the few side effects it causes—occasional dizziness, sensations of hot or cold, blurring of vision—tolerable. Vancouver neurosurgeon Dr. Ian Turnbull, who plans to implant six stimulators this coming year, says that out of his 17 patients who received DBS over the past four years, all suffered from pain caused by nerve injury; 13 experienced complete or partial relief; four did not respond to stimulation during surgery and never received permanent implantation. “Why DBS works for some people and not others, I can’t tell you,” says Turnbull. “But I do know that it’s very effective in some cases.” Medical journals are full of miraculous DBS case studies—one man, for example, a 31year-old house electrician, was out-ofwork for two years because of low-back pain; after DBS, he was able to work as a bricklayer.

More than $10 billion is spent on analgesic drugs and surgery each year and until recently, the only effective treatment of chronic pain involved cutting pain pathways in the brain and spinal cords. Benefits, unfortunately, were not long-lasting—usually only two or three years. For this reason, there has been a great interest in the potential for electrical stimulation. Not all observers, however, are optimistic. Dr. Ronald Tasker, a neurosurgeon at the Toronto General Hospital, is highly critical: “The devices are man-made and just like heart pacemakers, they can have breakdowns, which means you have to perform corrective surgery. Another reason the results of DBS have not been more dramatic may be due to the fact that surgeons reserve this little known and yet unproven procedure for their most hopeless cases.

“DBS is a controversial issue among neurosurgeons because there’s never been a carefully controlled study,” says Dr. Paul Clarke, Ontario health ministry representative for a provincial task force that has been investigating electrical stimulation for more than a year. “Ours will be the first—participating medical schools in Toronto, Ottawa, Kingston, London, and Hamilton will subject each patient’s case to the scrutiny of an independent, objective, preand post-operative assessment.” The study should be completed in several years and will affect Ontario’s decision to cover such procedures under the provincial health insurance plan. Currently, two provincial plans—Alberta and B.C. and the Workmen’s Compensation Boards in B.C. and New Brunswick cover the complete medical costs— about $7,000.

“The thalidomide experience made us very cautious about introducing new concepts in medicine, and rightly so,” says Dr. Adrian Upton, a neurologist at McMaster University, “but we must remember that the first antibiotics were arsenic compounds that could kill you if you took too much. The theory behind DBS is a good one, and it’s likely that as equipment improves, results will improve. We mustn’t dismiss a good idea in its infancy.” Elaine Waese

Elaine Waese