With Deep-Brain Stimulation, Neurosurgeon Believes In Magic

Deep-Brain Stimulation

A surgical procedure most closely associated with relief of tremors in patients with Parkinson ,, s disease is offering relief for other movement disorders and soon will be considered at Ohio State University Medical Center for those with select psychiatric disorders as well.

The procedure, deep-brain stimulation, delivers electrical pulses directly to brain tissue that controls movement, often dramatically reducing tremors or problems of rigidity in patients with Parkinson ,, s disease by interrupting signals that cause those symptoms. But to date, Ohio State neurosurgeons have also performed the surgery on a handful of patients with multiple sclerosis, with promising results.

"I tell patients it ,, s magic, said Dr. Atom Sarkar, a neurosurgeon at Ohio State ,, s Medical Center specializing in deep-brain surgeries. "It ,, s the closest thing we have in neurosurgery to magic. We don ,, t really understand completely how it works.

Early medical attempts to control tremors through brain surgery involved actually burning the surface of the brain through a technique called ablation. Some patients experienced relief, but not all " and either way, their brain tissue remained permanently damaged. Now, surgeons place an electrode in the brain to achieve the same results. If it doesn ,, t provide relief, they can remove the electrode with little or no loss of brain tissue.

Discovered serendipitously by French surgeons in the 1980s, the stimulation procedure typically is used for tremors but now is being considered as a potential therapy for other movement disorders. Sarkar is expanding the DBS program at Ohio State to include patients with a variety of conditions, including those that aren ,, t yet established applications for the surgery: multiple sclerosis, Tourette ,, s syndrome, epilepsy (in patients who don ,, t respond to standard epilepsy surgery), depression and obsessive-compulsive disorder.

"It ,, s empiric " we ,, ve been able over time to identify targets that will give different patients relief from their various disorders, Sarkar said. "At an academic medical center, we are more than willing to try to expand the application.

Patients undergoing deep-brain stimulation typically are those whose quality of life has decreased significantly because of limitations caused by their movement disorder, or those whose medications no longer effectively control symptoms.

One of the mysteries of the procedure, according to Sarkar, is that it can reduce two kinds of symptoms in patients with Parkinson ,, s disease " tremor and immobility.

"We understand that Parkinson ,, s is associated with a dopamine deficiency but we don ,, t understand why some patients present with rigidity and others with tremor, he said. "We do observe that the electrode in the brain structure helps both kinds of conditions.

The procedure involves a surgically implanted, battery-operated medical device that delivers electrical stimulation to targeted areas in the brain, blocking the abnormal nerve signals that cause tremor other symptoms. For example, in Parkinson ,, s disease, the electrode is commonly placed in the subthalamic nucleus, the base for nerve cells that play critical roles in the control of movement. In patients with MS and a condition called essential tremor, the thalamus is targeted. Both sections are in the central area of the brain.

After placing the electrode, surgeons practice the stimulation during the operation to initially gauge its effectiveness and to observe any potential side effects. "These patients are superstars because they have to be awake for this, Sarkar said.

The electrodes are attached via a thin wire passed under the skin to an external battery, or neurostimulator, placed under the collarbone in a separate procedure after the brain surgery. About two weeks later, the stimulator is turned on and begins sending the therapeutic signals to the brain through the electrode. Waiting periods between procedures allow for healing and reduction of swelling. Batteries are typically changed every three to five years.