Health Technology Brief

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Magnetic Resonance–Guided Focused Ultrasound (MRgFUS) Unilateral Thalamotomy for Essential Tremor

August 28, 2019

Health Problem: Essential tremor (ET) is a neurological disorder of involuntary rhythmic tremors. Although ET is considered a benign disease, disabling tremors affect activities of daily living and workplace productivity and are a source of psychological distress and embarrassment. Medication-resistant ET occurs in 30% to 50% of patients with ET. While approximately 50% of patients with ET achieve symptom reduction; complete resolution of tremor symptoms is rare.

Technology Description: Transcranial magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an incisionless therapy option that does not use ionizing radiation for thermal ablation of a part of the thalamus.

Controversy: Invasive alternatives to MRgFUS have the risks associated with open surgery, including infection, hemorrhage, and damage to nontargeted areas; the radiosurgical alternative entails exposure to ionizing radiation exposure and may result in delayed onset of clinical effect.

It is not known if, in the event of failed thalamotomy with MRgFUS, a subsequent open surgical procedure can be performed safely and effectively, or if MRgFUS can be used as rescue for failed open surgery. Furthermore, lesional approaches to thalamotomy, such as the MRgFUS, have focused on unilateral surgery due to safety concerns; the safety of bilateral MRgFUS thalamotomy is unknown.

Key Questions:

  • Is unilateral MRgFUS thalamotomy effective for the treatment of moderate-to-severe medication-refractory essential tremor ET?
  • How does unilateral MRgFUS thalamotomy compare with clinical alternatives for the treatment of medication-refractory ET?
  • Is unilateral MRgFUS thalamotomy safe?
  • Have definitive patient selection criteria been identified for unilateral MRgFUS thalamotomy?