TORONTO—High-frequency stimulation of the subthalamic nucleus is the surgery of choice for patients with advanced stage Parkinson’s disease, said Alim-Louis Benabid, MD, PhD, at the 2001 Annual Meeting of the American Association of Neurological Surgeons. More effective than medical or other surgical treatments, the surgery involves ventriculography, followed by the placement of bilateral subthalamic nucleus electrodes and stimulators. Dr. Benabid is Director of the Neurobiophysics Laboratory at Joseph Fourier University in Grenoble, France.

“Subthalamic nucleus deep brain stimulation is a front runner and currently the most effective therapy for our patients with Parkinson’s disease,” concurred Andres M. Lozano, MD, PhD, who filled the role of discussant to comment on the research presentation. “Dr. Benabid has demonstrated that high-frequency stimulation of the subthalamic nucleus is more effective than other surgical treatments for Parkinson’s disease,” Dr. Lozano continued. While high-frequency stimulation of the subthalamic nucleus has improved Unified Parkinson Disease Rating Scale (UPDRS) III scores by 62%, bilateral pallidotomy is associated with a UPDRS score improvement of 50% to 55%, unilateral pallidotomy with a 30% improvement, and fetal cell transplantation with an 18% improvement, noted Dr. Lozano. He is a Professor in the Department of Surgery at the University of Toronto and a consultant with the Divisions of Neurosurgery at The Toronto Hospital and Mount Sinai Hospital, Toronto.

BENEFITS ARE SIGNIFICANT AND LONG LASTING

Since 1993, Dr. Benabid and colleagues have treated 125 patients with advanced idiopathic Parkinson’s disease with high-frequency stimulation of the subthalamic nucleus using chronic bilateral electrodes. The patients (60% male; mean age, 56 ± 8) were taking 1,500 ± 800 mg of levodopa and had a UPDRS III score of 59 ± 10 in the off stage.

The eight-year study demonstrated that high-frequency stimulation of the subthalamic nucleus improved off-stage dystonia by 95%, tremor by 80%, and akinesia and rigidity by 60%. The reduction of levodopa by 70% at three months was associated with the resolution of levodopa-induced dyskinesias. “After several years, it was almost impossible to induce dyskinesias anymore,” Dr. Benabid noted.

The benefits of this surgical treatment are long lasting, he said. Five years after surgery, although 25% of the patients were impaired, 36% were stable. This is normally never seen in Parkinson’s disease, he noted. He added that surgical outcomes continue to improve as his team becomes more experienced with the procedure.

EARLIER TARGETING

Compared with ablative surgery, the complications associated with this procedure are limited, said Dr. Benabid. There was no operative mortality, three patients developed an unrelated intracerebral hematoma, and eight patients developed local infections. “Implantation of electrodes induced 2% symptomatic hemorrhage and the confusion that is seen in more than 20% of the patients, depending on age and severity [of disease] of the patient,” he noted. Stimulation-related complications were seen in 15% of the patients, some of whom had exhibited these symptoms before surgery.

“We initially targeted the patients when surgical treatment was indicated, when medical treatment failed, and when the patient had severe disability in the motor response and was not yet demented,” said Dr. Benabid. “Currently, we extend this indication to patients who have not yet lost comfort, job, friends, and spouse. The trend is to operate on patients as soon as you are sure that the rapid progression of symptoms and doses will lead them to the end stage,” he said.

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