376 Laser Interstitial Thermal Therapy for Deep-Seated Perivascular Brain Tumors: Evaluating the Risk of Distal Ischemia

Abstract

INTRODUCTION: Laser interstitial thermal therapy (LITT) is a novel minimally invasive cytoreductive treatment option for primary and metastatic brain tumors. By relying on stereotactic guidance, the use of LITT carries a risk for direct and thermal vascular injury, especially when targeting deep-seated tumors with surrounding critical vasculature. It is thought that nearby blood vessels act as heat sinks from thermal injury, however, the risk of ablation causing an ischemic stroke is not well reported. METHODS: A retrospective review identified patients who underwent LITT between 2013 – 2021 for brain tumors located within the insula, basal ganglia, and thalamus. Demographic, clinical, and volumetric characteristics were collected. The primary outcome was radiographic evidence of distal ischemia on post-ablation imaging. RESULTS: A total of 50 patients underwent 59 ablations for perivascular brain tumors located in the insula (52%), basal ganglia (24%), and thalamus (24%). Of the tumors treated, 22 (37%) were low-grade gliomas, 32 (54%) were high-grade gliomas, and 5 (8%) were metastatic. No coagulopathies were identified in any patient. A biopsy was performed in 72% of patients. The mean volume of ablation was 12.4 cm3 (S.D. 13.9) with a median extent of ablation of 92% (IQR 30%, 100%). Two patients developed symptomatic intracerebral hemorrhage. One developed a tract hemorrhage attributed to vessel injury from fiber insertion. The other presented with delayed onset hemorrhage one week later due to uncontrolled hypertension. In all patients, there was no radiographic evidence of distal ischemia following LITT on DWI sequencing . The median length of stay was 2 days with 81% of patients being discharged home. CONCLUSIONS: We demonstrate that LITT has minimal risk for new onset distal ischemia for deep-seated perivascular brain tumors.