Objective: To describe a novel case of gamma knife radiosurgical (GKRS) thalamotomy for treatment of refractory essential tremor (ET) with delayed onset adverse effects due to lesion progression.

Background: ET is considered the most common movement disorder in adults, and is associated with significant physical and psychosocial disability. While medical therapy is first line therapy, pharmacologic agents are often inadequate in controlling severe symptoms or cause intolerable adverse effects. GKRS thalamotomy is an effective treatment of refractory ET for patients who are not eligible for deep brain stimulation or prefer a non-incisional advanced therapy option. Reports of adverse effects beginning more than 1 year after GKRS are rare.

Method: A 73 year-old left-handed male with familial essential tremor present for more than 30 years and refractory to primidone and propranolol underwent stereotactic GKRS (130 Gy dose) to the ventral intermediate nucleus (VIM) of the right thalamus.

Results: 3-6 months after GKRS, the patient experienced gradual and significant improvement in left hand tremor, with improvement in hand writing and pouring from cups (see figure 1). MRI brain 4 months post-op showed an appropriate corresponding 6 mm oval lesion with peripheral enhancement in the right thalamus, with associated abnormal FLAIR signal. 31 months after GKRS, he developed paresthesia of the left hand and mouth. MRI brain showed an increase in previously seen rim-enhancing lesion at the site of the right thalamotomy, measuring 1.1 x 1.0 cm, with surrounding vasogenic edema, extending into the posterior limb of the internal capsule (see figure 2). He was treated with oral steroids, with unknown symptom response.

Conclusion: GKRS thalamotomy is a reasonable option for ET patients with medically refractory tremor who cannot undergo incisional/invasive treatment. However, sensitivity to gamma radiation can be idiosyncratic, with adverse effects or benefits occurring year(s) after the procedure.

« Back to MDS Virtual Congress 2020

MDS Abstracts - https://www.mdsabstracts.org/abstract/delayed-lesion-adverse-effects-of-gamma-knife-radiosurgical-thalamotomy-for-essential-tremor/