ITVT-05. Intraoperative Ultrasound Guidance Improves Resection In Gliomas – Results From A Single Centre Propensity Matched Comparative Cohort Analysis Of 2D Vs Navigated 3D Ultrasound In 500 Gliomas

Abstract

Abstract INTRODUCTION Intraoperative ultrasound (iUS) is a promising tool for glioma surgery. Navigated 3-D (n3D) iUS has many benefits over standard 2-D iUS. METHODS This was a retrospective comparative cohort study using propensity score matching (PSM). 500 consecutive histologically confirmed gliomas were divided into 2 cohorts – 2DiUS - Cohort A; and n3DiUS -Cohort B. PSM was used to account for known confounders (250 in each group; 1:1 matching). Gross total resection rates (based on iUS findings as well as postoperative MR) and perioperative morbidity were analyzed across the groups as were factors influencing these outcomes (using univariate as well as multivariate regression models). RESULTS Overall, the majority of the patients were adults (94%), males (71%) with hemispheric tumors (96%). 35% had tumors close to eloquent regions and 23% had received some prior treatment. The majority were high-grade gliomas (85%). 2D iUS was employed mainly for localization (80%) whereas n3D was used predominantly for resection control (84%) [p < 0.001]. GTR rate was higher in the n3D cohort (55.2% vs 38.4% in 2D; p = 0.001). The odds of having a complete resection in the n3D cohort was twice that of the 2D. Prior treatment, hemispheric location, and use of fluorescence were also significantly associated with higher GTR rates on univariate analysis. On multivariate analysis, all of these remained significant. There was no difference in the morbidity rates in the two cohorts. N3D iUS had a higher specificity and positive likelihood ratio in detecting tumor residue. CONCLUSION For hemispheric gliomas undergoing resective surgery, the use of navigated 3D ultrasound improves GTR rates, with no added morbidity. It is more likely to be used for resection control mode than is 2DUS and this is probably because n3DUS is more specific and likely to pick up tumor residues contributing to its better accuracy.