Neurosurgery
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Stereotactic radiosurgery (SRS) is widely accepted as a minimally invasive alternative to surgery in the management of arteriovenous malformations (AVMs). Dilated AVM outflow veins or varices may be caused by high-flow or partial outflow obstruction, which may increase the risk of a hemorrhage before or after SRS. ⋯ The presence of AVM variceal venous drainage did not affect the obliteration rate and did not confer a higher risk of a subsequent hemorrhage both before and after SRS.
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During focused ultrasound ablation (FUSA), the presumed stereotactic target is tested with subthreshold sonications before permanent ablation. This testing relies on ultrasound-induced reversible clinical effects (thermal neuromodulation, TN). However, the thermal dose and spot size thresholds to induce TN are not yet defined. ⋯ The TN thermal dose and spot size thresholds are significantly higher than the current FUSA standard of care. We recommend long duration (>30 s), subthreshold sonications for intraoperative testing during FUSA. Future investigations should test whether the thermal dose threshold is tissue-specific and determine the mechanisms underlying focused ultrasound TN.