DOES THE ADDITION OF INTRA-OPERATIVE ULTRASOUND TO MULTIMODAL (AWAKE, TRACTOGRAPHY AND 5-ALA GUIDED) ELOQUENT GLIOBLASTOMA RESECTION IMPROVE EXTENT OF RESECTION: A RETROSPECTIVE MATCHED COHORT STUDY

Abstract AIMS Maximising extent of resection (EOR) with eloquently located glioblastoma must be balanced against risk of neurological deficit. The optimal surgical adjuncts to enable maximal safe resection remains undefined. We present the first series to assess the safety and efficacy of awake craniotomy (AC) using 5-aminolevulinic acid (5-ALA) and tractography, with and without the additional use of intraoperative ultrasound (USS) guidance to resect Isocitrate Dehydrogenase (IDH) Wildtype GB. METHODS We conducted a single-centre retrospective matched cohort study (1:1) of patients undergoing AC for primary resection of eloquently located IDH-Wildtype GB, over a 10-year period, between January 2014 and January 2023. Outcomes assessed included neurological complications, EOR and overall survival (OS). RESULTS 156 patients (92M:64F, mean age 57.2 years) were included, with 78 patients having the use of intraoperative USS and 78 patients without. All cases used neuronavigation, 5-ALA and DTI. The cohorts were well-matched in age, gender, WHO performance status, tumour volumes, lobar and functional locations. Gross total resection (>98%) was achieved in 101/156 patients (64.7%), whilst 51/156 patients (32.6%) had a near total resection (95- 98%). The median percentage EOR with USS was 100%, whilst without USS was 97.8% (Wilcox, p=0.0004). There was no increased risk of permanent neurological deficit with this more complete resection achieved with USS (Fisher’s Exact test p=0.65), suggesting it was not of inferior safety. Median OS was 19.0 months (95% CI: 16.7 – 21.3 months). CONCLUSION Intraoperative USS is a widely available, cost-effective option for the real-time visualisation of tumour residual to facilitate maximal resection, in conjunction with other operative adjuncts. It is reported that USS and 5- ALA provide different information about tumour extent, and when combined intraoperatively, enhance EOR synergistically.