ABSTRACT
In this chapter the author describes his experience and that of others in the use of the Gamma Knife (Gamma Knife is a registered trademark of Elekta, Inc., Norcross, GA, USA) radiosurgical instrument to make lesions in the ventral intermediate thalamic nucleus to treat tremor of a variety of causes or in the internal segment of the globus pallidus to treat rigidity, bradykinesia, and L-dopa-induced dyskinesias in Parkinsonian patients. Patient selection for gamma knife procedures to treat movement disorders is similar to that for radiofrequency thalamotomy or deep brain stimulation except that patients of advanced age, those with other serious medical illnesses, and those utilizing anticoagulants may be treated safely with the Gamma Knife. Between 85 and 90% of patients with Parkinsonian tremor or essential tremor are rendered either tremor-free or nearly so following radiosurgical thalamotomy. These improvements are maintained in patients who have been followed between 4 and 8 years after the procedures. About 50% of patients with tremors of other origins may be improved although complete freedom from tremor has not been identified. Significant improvements in bradykinesia and rigidity occur in Parkinsonian patients, particularly in the ``off'' state, following radiosurgical pallidotomy. More than 85% of patients are rendered free of L-dopa-induced dyskinesias following radiosurgical pallidotomy. These improvements are maintained in patients followed more than 4 years after the procedures. Only 5 patients of more than 300 treated (1.7%) developed any side effects from the procedures. Radiosurgical thalamotomy and pallidotomy are effective and safe procedures for the treatment of movement disorders. For patients who take chronic anticoagulants, they may be the only form of surgical therapy available. Radiosurgical procedures are as effective as radiofrequency procedures or deep brain stimulation procedures and should be considered and presented as surgical options to patients who are surgical candidates for the treatment of movement disorders.
KEYWORD
Radiosurgery - Parkinson's disease - essential tremor
