Jan. 17, 2002 St. Louis, — Deep brain stimulation for patients with Parkinson’s Disease (PD), approved by the Food and Drug Administration (FDA) on Monday, is available from Washington University physicians at Barnes-Jewish Hospital.
The implanted device, made by Medtronic Inc., delivers continuous, high frequency electrical stimulation to a particular region of the brain in order to disrupt brain signals that otherwise cause disabling symptoms.
The deep brain stimulator was FDA approved in 1997 for use in one region of the brain, the thalamus, to reduce tremor. Though patients with PD often experience tremor, it is only one of many disabling symptoms. The approval announced Monday allows neurosurgeons to implant the device in a nearby region, the subthalamic nucleus, a procedure that has been proven to not only relieve tremor but also alleviate the other symptoms of PD.
Though the 1997 FDA approval did not specifically address the use of deep brain stimulation in the subthalamic nucleus, approval of the device itself allows physicians to use it in ways they feel are beneficial for the patient. A team of neurologists and neurosurgeons at Washington University School of Medicine in St. Louis therefore have been implanting the stimulator in both the thalamus and in the subthalamic nucleus for the past few years.
“This may be one of the best treatment options available for selected patients with advanced Parkinson’s disease, but not all patients are good candidates for this surgery,” says Fredy J. Revilla, M.D., a neurologist at the Movement Disorder Center at Washington University. “Those who already have undergone the procedure have had dramatic improvements.”
Joshua L. Dowling, M.D., assistant professor of neurological surgery at the School of Medicine and Keith M. Rich, M.D., associate professor of neurological surgery, of radiology and of anatomy and neurobiology, already have implanted the device in close to 100 patients with PD and other forms of tremor at Barnes-Jewish Hospital. Their hope is that this surgical option will be more accessible to the public and that insurance companies will more readily pay for the procedure in PD patients now that it has FDA approval.
“We’ve had remarkable success using this procedure in PD patients,” says Dowling. “Many patients return to a relatively normal, active life, usually with a significant reduction in their medication. We’re thrilled that the FDA has approved the procedure for these patients.”
The subthalamic nucleus is one of the brain regions involved in controlling movement and is overly active in patients with PD. Patients therefore may experience a number of symptoms including tremor, slowness of movement, stiffness and difficulty talking. Drugs help to “unfreeze” the muscular system, but often cause frequent, exaggerated involuntary movements, limiting their functional benefit. Deep brain stimulation of the subthalamic nucleus provides good symptomatic relief with much lower doses of medication, reducing the side effects.
Other surgical procedures including pallidotomy and thalamotomy also can improve the symptoms of PD, but these procedures involve destroying a small area of brain tissue and are irreversible. Therefore, there is higher risk of permanent undesirable side effects. “Subthalamic nucleus deep brain stimulation works better with overall lower risk,” says Dowling.
The stimulator consists of three parts. A thin, flexible wire, called the lead, is implanted into the brain with four electrodes extending into the subthalamic nucleus. Another wire connects the lead to the Implantable Pulse Generator, a metal device roughly the size of a heart pacemaker. The generator generally is implanted near the collarbone and is battery-operated, thus generating power for the electrodes in the brain.
The device can be turned on and off or removed if necessary, and stimulation levels are adjusted according to individual needs.
In addition to its clinical uses, the deep brain stimulator provides a unique way to study the underlying cause and manifestation of PD. Researchers at the School of Medicine are combining imaging techniques with deep brain stimulation to find out more about the disease itself.
The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
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