Expanding Applications of Deep Brain Stimulation: Cluster Headache, Tourette Syndrome, Chronic Pain

Points to Remember

• Deep brain stimulation (DBS) is an evolving type of neurosurgery first used to treat movement disorders. It is emerging now as an effective therapy for nonmotor disorders.
• Expanding applications for DBS at Mayo Clinic include cluster headache, dystonia, chronic pain, and Tourette syndrome.
• DBS is generally reserved for patients in whom pharmacologic and other treatments are no longer effective or who have disabling adverse effects from medical treatments. Careful evaluation and review of potential candidates for DBS surgery by neurologists, neurosurgeons, psychiatrists, and other professionals is necessary to determine the patients for whom surgery is appropriate.

Deep Brain Stimulation Surgery

The goal of deep brain stimulation (DBS) is to restore function by stimulating brain tissue at specific sites deep in the brain. DBS was developed in the 1980s in Europe. Neurosurgeons from Mayo Clinic in Jacksonville, Florida, traveled to Europe for training in 1997 and were among the first to perform DBS surgery in the United States. DBS was principally used to treat movement disorders associated with essential tremor and Parkinson disease.

An electrode is implanted into a group of nerve cells in the brain.

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In DBS surgery, electrodes are implanted in a specific area of the patient's brain to target nerve cells that demonstrate irregular behavior. Pulses of electricity are delivered through the stimulation electrode and regulated by programming a pulse generator implanted near the patient's clavicle. The electrical pulses reorganize neural circuits and neuronal activity to normalize brain function. DBS is both reversible—turning off the generator ends the therapy—and highly individualized through adjustments to the pulse generator.

DBS at Mayo Clinic

Laboratory investigations have produced new insights into the role of electricity in reorganizing neural circuits and brain function. Combined with frank clinical need and excellent results in treating motor syndromes, the new research findings drive the trend of applying DBS therapy to include nonmotor syndromes and conditions.

Mayo Clinic has expanded its DBS program to include new treatment approaches and innovative research to refine and improve DBS surgery. Mayo Clinic neurosurgeons using DBS surgery have treated segmental or focal dystonias such as writer's cramp and spasmodic torticollis. DBS has also been successful in some patients with Tourette syndrome, although this application is under study. Tourette symptoms fluctuate over time, so long-term follow-up, currently under way in an international study, is critical.

Some success has also been seen in patients with cluster headaches and for another rare headache syndrome. Other conditions under consideration for DBS treatment at Mayo Clinic include epilepsy, depression, and obsessive-compulsive disorder.

Stereotactic head frame

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DBS is generally reserved for patients in whom pharmacologic and other treatments are no longer effective or who have disabling adverse effects. Not all patients with a given disorder are candidates. Interdisciplinary teams meet regularly at each Mayo Clinic site. These teams evaluate patients, formulate treatment recommendations, and provide multiple perspectives on current practice and future clinical and research directions for DBS.

Mayo Clinic is also active in research concerning the mechanisms of DBS. This is creating a better understanding of the procedure and its benefits.

What to Look for in a DBS Program

A successful DBS program needs 3 key components: 1) careful patient selection, 2) precise targeting of the neural structures during the surgical procedures, and 3) intense, highly individualized postoperative care and follow-up to make sure the pulse generator is programmed optimally.

Careful Patient Selection

The first step is comprehensive clinical evaluation by a neurologist on the DBS team that is tailored to the disorder. This evaluation typically includes tests of memory, cognitive function, and speech and language and possibly a psychiatric evaluation for depression or other disorders. Evaluations are also done by a neurosurgeon and possibly a pain specialist.

Surgeons review electrophysiologic recordings

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Surgical Procedure

The brain structures targeted during DBS surgery vary according to the condition being treated. To locate a target a stereotactic head frame is applied to the patient, an MRI is obtained, and that image is merged with a brain atlas. These images, along with electrophysiologic recordings, allow the surgical team to precisely locate the anatomic target. The surgeon aims a microelectrode inserted through a small hole in the patient's skull. The brain-mapping software developed at Mayo Clinic has helped Mayo DBS teams achieve an exceptionally accurate targeting history.

DBS surgery is generally done with the patient awake to evaluate patient responses to intraoperative stimulation. The surgery may include implantation of electrodes and a pulse generator.

Individualized Aftercare

Follow-up requires continued evaluation by an experienced team to adjust medications and make any stimulator programming adjustments, especially during the first 6 months after surgery.