Successful MRgFUS VIM Thalamotomy for essential tremor nearby cavernous malformation: image case report

INTRODUCTION: Essential tremor (ET) is the most common movement disorder, whose severe and refractory cases 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). CASE PRESENTATION: A 78-year-old male with refractory bilateral upper limb postural/action tremor was consented and 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), using increased low-medium power to avoid cavitation, and applying relatively long durations to reach the required energy (eight sonications targeting 50-55°C). The patient experienced no adverse effects, demonstrated significant tremor improvement, and postoperative imaging confirmed a well-defined lesion without complications. DISCUSSION: The distinct histopathological features of CCMs, including slow flow and absence of arterial feeders, produce a more favorable profile compared to other cerebrovascular lesions. However, low blood flow may pose a higher risk during thermal ablation, therefore avoidance of direct ultrasound trajectories through the malformation, 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.