Gamma knife thalamotomy provides durable long-term relief from essential tremor: a 30-year single institution experience.

BACKGROUND

Gamma Knife (GK) stereotactic radiosurgical thalamotomy is a minimally invasive treatment option for medically refractory essential tremor (ET), but long-term outcome data remain limited. We evaluated three decades of institutional experience to characterize tremor improvement, functional outcomes, safety, and durability of response after GK thalamotomy.

METHODS

We performed a retrospective single-institution cohort study of 163 GK thalamotomy procedures for ET. All procedures targeted the contralateral ventral intermediate nucleus of the thalamus. Primary outcomes included clinical benefit, complete tremor arrest, adverse radiation effects (AREs), and tremor recurrence. Functional outcomes were assessed using pre- and post-treatment Fahn-Tolosa-Marín Tremor Rating Scale (FTM) scores, including tremor, writing, drawing, drinking, and total FTM score.

RESULTS

Mean age at treatment was 74.1 ± 11.1 years, and follow-up duration averaged 95.1 months, with a median of 97 months (range, 15-356). Clinical benefit was observed in 152 of 163 procedures (93.3%), with a median time to benefit of 4.0 months (IQR 2.0-6.0). Complete tremor arrest occurred in 39 procedures (23.9%). AREs occurred in 6 procedures (3.7%). Tremor recurrence was documented in 16 procedures (9.8%), with a median time to recurrence of 26.0 months. All functional domains improved significantly after treatment (all p < 0.001). Mean total FTM score improved from 12.26 ± 2.20 to 5.00 ± 4.02.

CONCLUSIONS

GK thalamotomy was associated with meaningful and durable tremor improvement in medically refractory ET, with significant functional improvement, infrequent AREs, and low recurrence over long-term follow-up.