Cortical mapping and resection under local anaesthetic as an aid to surgery of low and intermediate grade gliomas

We report four cases of the use of per-operative cortical mapping during craniotomy under local anaesthesia to define the relationship between the glioma and speech and somatosensory cortex. This enabled a radical subtotal (two cases) or an apparent total (two cases) excision of the tumour close to somatosensory and speech cortex with no permanent neurological deficit. Use of this technique allows radical excision of intrinsic low and intermediate grade gliomas that would otherwise be considered unexcisable and may lead to an improved survival.