Parkinson's Brain Implant Approved

Originally Published MDDI February 2002

NEWS & ANALYSIS

James Dickinson

FDA in January approved expanded labeling for a Medtronic deep-brain stimulator, the Activa Parkinson's Control System originally approved in 1997. Based on new clinical studies, the new labeling provides for use of the device in both sides of the brain to help control symptoms of advanced Parkinson's disease that can't be adequately controlled with medication.

The 1997 approval was for use in one side of the brain to help control tremors on one side of the body.

The Activa system, FDA said, consists of electrodes that are implanted into the brain and connected by leads under the skin to a pulse generator implanted in the abdomen or chest. The pulse generator sends a constant stream of tiny electrical pulses to the brain, blocking tremors. When the device is implanted in both sides of the brain, two separate systems are used.

To turn the stimulator on and off, FDA said, the patient holds a magnet over the pulse generator. The generator must be replaced every three to five years, the life of the battery.

Some 160 patients with advanced Parkinson's disease were enrolled at 18 medical centers in the United States, Canada, Australia, and Europe. The device was implanted bilaterally in 134 patients. The implant procedures were done simultaneously or in stages. The patients were followed for approximately one year.

During the study, FDA said, patients were evaluated for a variety of Parkinson's symptoms using a test for total motor skills, including hand movement, leg agility, facial expression, rigidity, tremor, and speech. They were tested with the Activa system turned on, both with and without medication. Total motor skills improved in nearly half the patients taking medication and approximately 90% of the patients not taking medication.

According to FDA, nearly all of the 160 patients enrolled in the study experienced one or more adverse events. During the entire study, 7.5% had bleeding into the brain; 11% had device-related infection; 10% had paralysis, and 8% had weakness. Some 37% of the adverse events were related to the Activa system. Six percent of the device-related adverse events were serious and ongoing, including a worsening of motor impairment and other Parkinson's symptoms.

Copyright ©2002 Medical Device & Diagnostic Industry