Gamma knife thalamotomy (GKT) is a safe and effective treatment for medically refractory Parkinson disease (PD) tremor, especially for the elderly or those not suitable for deep brain stimulation or thermal thalamotomy, a recent study found. Researchers retrospectively studied the outcomes of 33 patients who were treated with GKT over a 19-year period. 12 patients were ≥80 years. A median dose of 140 Gy (range, 130-150 Gy) was delivered to the nucleus ventralis intermedius through a single 4-mm isocenter. They scored tremor, handwriting, drawing, and ability to drink fluids. and found:

• After GKT, 31 patients (93.9%) experienced improvement in tremor.
• 23 patients (70.0%) had complete or nearly complete tremor arrest.
• 9 patients (27.2%) noted tremor arrest and resolution of impairment in writing, drawing, and ability to drink fluids.
• 1 patient (3%) improved in bradykinesia, 3 patients (9%) improved in rigidity, and 3 patients (9%) decreased their dosage of dopa after GKT.
• Tremor relief was fully maintained in the last follow-up for 96.8% of responding patients.