Unilateral MR-guided high-focus ultrasound ablation of the cerebellothalamic tract for essential tremor is based on the concept of subthalamotomy. It leads to better clinical outcomes with fewer side effects.
Background: Stereotactic therapeutic procedures such as deep brain stimulation and MR-guided high-focus ultrasound ablation in the nucleus ventralis intermedius (VIM) of the thalamus have been successfully used for essential tremor. Choosing the cerebellothalamic tract as the stereotactic target is based on the concept of subthalamotomy and also better clinical outcomes with fewer side effects when stimulating the fiber tracts caudal to the VIM.
METHODS: This prospective, uncontrolled, single-center study included 6 patients with essential tremor and inadequate symptom control. Before the intervention and 48 hours, 1, 3, and 6 months afterward, patients were clinically examined and videos were evaluated by tremor scores in a blinded fashion.
Results: 6 months postintervention showed a statistically significant reduction of tremor of 83% and improvement of quality of life of 52% compared to test results pre-intervention without impairment of coordination of both hands or cognition. Transient side effects such as subjective clumsiness of the treated hand and gait unsteadiness had disappeared after 3 months. 4 of 6 patients reported dizziness toward the end of the intervention, which, however, immediately subsided after termination of sonication.
Comment: Unilateral MR-guided focused ultrasound ablation of the cerebellothalamic tract in the treatment of essential tremor is effective and safe. However, further larger studies and also comparative studies between VIM vs CTT ablation are crucial to define the best target point.
InFo NEUROLOGY & PSYCHIATRY 2017; 15(4): 34-35.
