FDA expands use of brain implant

WASHINGTON -- A brain stimulator used to control tremors now can be implanted deep into a different part of the brain to fight other debilitating symptoms of Parkinson's disease, the government ruled Monday.

Since 1997, doctors have been able to implant Medtronic Corp.'s pacemaker-like device into one side of a patient's brain to cut the tremors that plague patients with Parkinson's and certain other diseases. Tremor experts have called the Activa system a major advance.

The Food and Drug Administration's 1997 approval, however, said Activa implants were only for one side of the brain -- meaning it helped only one side of the body.

Monday, the FDA approved using Activa on both sides of the brain and in a slightly deeper spot, which promises to control not just tremors on both sides of the body but other troubling Parkinson's symptoms such as rigid arms and legs and the sudden, uncontrollable flailing of limbs called dyskinesia.

Up to 1.5 million Americans have Parkinson's disease, a degenerative neurological disease. The drug L-Dopa helps some Parkinson's symptoms, although its effects wane over time.

In a $25,000 procedure, doctors drill through the skull and implant an electrode into the brain. It is connected by a wire run just under the skin to the collarbone, where a generator is implanted. It sends electrical waves to the electrode, which emits constant, tiny electrical shocks customized to block tremors.

Doing the procedure on both sides of the brain will double the surgery's cost, a Medtronic spokesman said.

A study of 160 patients with advanced Parkinson's concluded that implanting two Activa systems, on opposite sides of the brain in areas called the subthalamic nucleus and the globus pallidus, significantly improved patients' motor skills.

The implants aren't without risk, the FDA warned. About 7.5 percent of study participants experienced bleeding in the brain, 11 percent had an infection related to the device and 10 percent experienced some paralysis.

Although Monday's approval means Medtronic can now promote the implant for both sides of the brain, the company agreed to an FDA demand that it continue to study the operation's long-term effects.