Gamma Knife Thalamotomy Gives Modest Benefit for Disabling Tremor


Last Updated: 2010-05-26 15:31:30 -0400 (Reuters Health)

NEW YORK (Reuters Health) - On average, gamma knife thalamotomy has a modest benefit on disabling tremor, Canadian researchers report.

There is a "very wide range" of response to radiation, and in time to response, co-author Dr. Elena Moro of the University of Toronto told Reuters Health by e-mail.

Dr. Moro and her colleagues assessed clinical outcomes after gamma knife thalamotomy in 14 patients with essential tremor and Parkinson's disease who were unwilling or ineligible to undergo deep brain stimulation or other surgical procedures.

The patients were followed for at least 6 months (and for an average of 19 months), and upper limb and head tremor were graded according to the Fahn-Tolosa-Marin Tremor Rating Scale. Other outcome measures included activities of daily living scores and the incidence of adverse events.

As reported in the May Archives of Neurology, gamma knife thalamotomy produced significant improvement only in Fahn-Tolosa-Marin Tremor Rating Scale activities of daily living scores (p = 0.03), with median and mean changes of 2.5 and 2.7 points, respectively (on a scale of 0 to 4). There were no significant changes in other items.

Handwriting showed a trend toward improvement (p = 0.07). Unified Parkinson's Disease Rating Scale activities of daily living scores tended to improve as well (p = 0.11).

Dr. Moro said gamma knife thalamotomy was "relatively safe" at her center. Overall, three patients developed delayed neurologic adverse events. These were mild in two patients and serious in one (who initially showed marked improvement).

"In our institution we currently reserve this modality of treatment for those who are not eligible for neuromodulation procedure," Dr. Moro said. "A lot of these patients would not have had treatment of any kind, were it not for the fact that a non-invasive modality of treatment is available."

Arch Neurol 2010;67:584-588.

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