OP40 * POST-OPERATIVE T2 HYPERINTENSITY IN PERI RESECTION MARGIN FOLLOWING AWAKE MACROSCOPIC INTRAGYRAL TOTAL RESECTION OF LOW GRADE GLIOMA IS NOT A RELIABLE MARKER OF RESIDUAL TUMOUR

Abstract

INTRODUCTION: Awake craniotomy for resection of tumours from eloquent brain area is an established technique. We describe six year outcome data of awake surgery for radiological low grade glial series tumours resected using natural subpial and vascular intergyral planes. We describe immediate post-operative radiological findings and its correlation with long term outcome. METHOD: This is a retrospective analysis of clinical and radiological records of awake craniotomies undertaken between 2007-2014. Patients were identified from operative department records and radiological data were retrieved from hospital's electronic image archive. A correlative analysis was done between immediate post-operative T2 changes and long term tumour progression. RESULTS: 38 patients underwent awake craniotomy with average age of 41.1 yrs(range 21-79). 6 patients have died (average survival 2.69 years, range 1-84 months) due to tumour progression. 5 of these had initial diagnosis of grade 3 tumour or above; 1 patient had malignant melanoma. 32 (85%) patients have survived the survey period(2.38 years, range 1-72 months).On MRI most patients had post-operativeT2hyperintensity around the resection margins. The T2hyperintensity persisted in 6 patient. This was correlated with either a peri-operative decision to sub-totally resect, or subsequent tumour progression. In other 32 patients the T2 changes either reduced or remained static. Histology of these patients showed 4 grade 2, 22 grade 3, and 6 grade 4 tumours. CONCLUSION: T2 changes in peri-resection brain parenchyma following a macroscopic complete resection of low grade tumours using awake techniques is not a reliable marker of tumour residual or recurrence. 85% of such changes resolved.