MNGI-33. RESULTS OF TRANSCRANIAL RESECTION OF OLFACTORY GROOVE MENINGIOMAS IN RELATION TO IMAGING-BASED CASE SELECTION CRITERIA FOR THE ENDOSCOPIC APPROACH

BACKGROUND: Endoscopic endonasal surgery (EES) is increasingly used for Olfactory Groove Meningiomas (OGMs). The role of EES for large (4cm) or complex OGMs is debated. Specific imaging features have been reported to affect the degree of gross total resection (GTR) and complications following EES for OGMs. The influence of these factors on transcranial resection (TCR) is unknown. OBJECTIVE: We examined the impact of specific imaging features on outcome following TCR to provide a standard for large and endoscopically less favorable OGMs against which endoscopic outcomes can be compared. METHODS: Retrospective study of patients undergoing TCR for OGMs 2002–2016. RESULTS: 50 patients (mean age 62.1 years, mean maximum tumor diameter 5.04 cm and average tumor volume of 48.8 cm3) were studied. Simpson grade 1 and 2 resections were achieved in 80% and 12%, respectively. A favorable functional outcome [modified Rankin Scale (mRS) 0–2] was attained in 86%. The degree of resection, mRS, mortality (4%), recurrence (6%), infection (8%) and CSF leak requiring intervention (12%) was not associated with tumor calcification, absence of cortical cuff, T2 hyperintensity, tumor configuration, tumor extension beyond midpoint of superior orbital roof or extension to posterior wall of frontal sinus. There was no difference in resection rates but a trend towards greater complications between three arbitrarily divided groups of large meningiomas of increasing complexity based on extensive extension or vascular adherence. CONCLUSION: Favorable outcomes can be achieved with TCR for large and complex OGMs. Factors which may preclude endoscopic resection do not negatively affect outcome following TCR.