Stereotactic MRI-guided Focused Ultrasound Mesencephalotomy

This phase 1 study investigates the safety and initial effectiveness of focused ultrasound lesioning of the contralateral mesencephalon for severe, opioid-resistant pain associated with head, neck, and brachial cancer. Safety: To evaluate the incidence and severity of adverse events associated with unilateral stereotactic focused ultrasound mesencephalotomy. Efficacy: To determine the level or degree of pain relief in the head, neck, and brachial regions using validated numeric pain scales and patient-reported measures of pain. The rationale for this proposed Phase 1 study is based upon: 1. The pain associated with head, neck, and brachial cancer is one of the most severe and difficult conditions because it is: * notoriously refractory to medical therapies, * localized to the highest regions of the neural axis and is thus not amenable to traditional surgical options like intrathecal opioids or spinal cordotomy, and * affects them during the terminal stages of life. 2. Stereotactic mesencephalotomy, targeted to the confluence of the spinoreticular and spinothalamic tracts, has been associated with pain relief from malignancy, but historical stereotactic methods lacked precision to reduce morbidity for routine adoption. 3. Focused ultrasound has been demonstrated to be a precise stereotactic lesioning modality, and the technique can be performed without incisions or craniotomy. Continuous closed-loop monitoring of the thermal ablation process with MRI has yielded lesion accuracies consistently \< 1 millimeter.