Successful MRgFUS VIM Thalamotomy for Essential Tremor Nearby Cavernous Malformation: Image Case Report

Essential tremor (ET) is the most common movement disorder, severe and refractory cases of which may benefit from neurosurgical interventions such as magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy. Cerebrovascular diseases are generally considered a contraindication for MRgFUS due to concerns of intracerebral hemorrhage; however, they are a heterogenous group of lesions, with distinct clinical behaviors. We present the first reported case of successful MRgFUS-thalamotomy for ET in a patient with a contralateral thalamic cerebral cavernous malformation (CCM).

A 78-year-old male with refractory bilateral upper limb postural/action tremor consented and was planned for a left-sided ventral intermediate nucleus (VIM) MRgFUS-thalamotomy. However, brain MRI revealed a right anterior thalamic CCM measuring 1.5 cm. After careful planning, a modified treatment was still carried out by blocking ultrasound trajectories intersecting the CCM (as well as calcifications) and with increased low-medium power sonications (eight sonications targeting 50-55°C). The patient experienced no adverse effects and demonstrated significant tremor improvement, and postoperative imaging confirmed a well-defined lesion without complications.

The distinct histopathological features of CCMs, including slow flow and the absence of arterial feeders, produce a more favorable profile compared to other cerebrovascular lesions. Avoidance of direct ultrasound trajectories through the malformation, the use of conservative temperatures, and continuous clinical monitoring were critical to ensuring procedural safety and efficacy. This case demonstrates the feasibility of MRgFUS-thalamotomy in carefully selected patients with coexisting CCMs.