SURGERY QUELLS DYSTONIA SYMPTOMS IN OTHERWISE UNTREATABLE PATIENTS


TORONTO -- Nine patients with dystonia symptoms unresponsive to conventional treatment found relief from new surgical approaches to the movement disorder, report Jerrold L. Vitek, M.D., Ph.D., and his Emory University colleagues at the recent meeting of the American Academy of Neurology.

Of nine patients who underwent unilateral surgical pallidotomy, six found significant, lasting improvement in muscle spasms and other symptoms of dystonia. Symptoms slowly recurred in two patients, but were significantly improved after undergoing a second surgery on the other side of the brain employing deep brain stimulation.

"Dystonia is a movement disorder that is poorly responsive to medical therapy," says Dr. Vitek, who is associate professor of neurology at the Emory University School of Medicine.

"Pallidotomy is an effective therapy for the treatment of patients with medically intractable dystonia," he says. "When used in combination with deep brain stimulation, both appendicular (dystonia in appendages) as well as axial dystonia may be greatly attenuated with significant improvement in both movement and disability and normalization (decreased coactivation and reduced overflow into adjacent muscle groups) of muscle activity both at rest and during movement."

Time of followup ranges from three months to two years after surgery. Measurements from two dystonia movement rating scales indicated an average improvement in patients' symptoms postsurgery of 67 percent and 45 percent, respectively.

During pallidotomy, neurologists use a microelectrode brain mapping procedure -- pioneered by the Emory team originally for Parkinson's disease -- to identify for neurosurgeons those few brain cells associated with dystonia. At Emory, Dr. Vitek and colleague Mahlon DeLong, M.D., chairman of neurology, are guided during pallidotomy by the electrical charges of single nerve cells as they pinpoint for neurosurgeon Roy A.E. Bakay, M.D., the troublesome cells in the pallidum to be ablated.

Deep-brain stimulation has been approved by the Food & Drug Administration only for tremor and epilepsy. Investigative treatment for dystonia involves the neurosurgical implantation of a pacemaker-type device under the skin below the clavicle that delivers controlled electrical stimulation to brain regions associated with dystonia, particularly the pallidum. Potential advantages involve performing procedures on both sides of the brain with less risk of permanent side effects that may be associated with bilateral ablative procedures. In addition, use of electrical stimulation allows physicians the flexibility to end or reverse treatment, or adjust stimulation frequencies to improve the effect of stimulation on dystonic movements.

Dystonia causes muscles to pull or spasm. Effects may be localized to particular regions such as the neck and shoulders, vocal cords, eyelids, arms or legs, or they may be more generalized. Because its effects are so varied and because symptoms may mimic other conditions, dystonia is difficult to diagnose, says study co-investigator Marion Evatt, M.D., assistant professor of neurology at Emory.

The research was supported by the Dystonia Medical Research Foundation.