Awake Surgery With Visual Pathway Mapping in Low Grade Glioma Surgery

Abstract

The visual pathway and its defects have been thoroughly studied in clinical correlation to temporal lobe lesions related to epilepsy and traumatic lesions. Nevertheless, its clinical correlation and other decisionmaking have not been addressed regarding neoplastic lesions. We present a case report of a 28-year-old man with a one-year history of generalized seizures and left superior homonymous quadrantanopia, with no other neurological disturbance on physical examination. According to diffusion tensor imaging tractography, MRI demonstrated a non-enhancing, right temporal lesion disrupting the visual pathway. An awake surgery with direct cortical electrostimulation of visual pathways was performed with subtotal resection of the tumor to preserve visual function, confirmed with postoperative MRI. Histopathological studies revealed a fibrillary astrocytoma.Surgical technique aided with intraoperative cortical and subcortical stimulation involving low-grade gliomas in eloquent areas is an exceptionally suitable procedure for complex cases where the visual pathway is compromised. Our objective is to describe how intraoperative mapping of visual function is performed in our institution and to comment on the relevant technical nuances, which can serve as a practical guideline for young neurosurgeons, as no previous cases have been reported in our country.

An update on tests used for intraoperative monitoring of cognition during awake craniotomy

“…Patient had to indicate movement direction. * Tested in wrist, elbow, toe, foot and knee Calculation Calculation task Clock reading Clock reading [ 224 ] Language Picture naming Motor Flexion and extension of the left arm and hand Executive function Stroop task Working memory Digit span Recall [ 225 ] Language Picture naming Auditory descriptive naming Non-word repetition Single word reading Writing Face recognition Famous face naming [ 226 ] Language Object naming ( Snodgrass naming task) Reading (Working) memory Digit span forwards Digit span backwards Executive functions DKEFS; Colour-Word Interference Test : inhibition condition DKEFS; Colour-Word Interference Test : Inhibition/switching condition Visuospatial Dot counting task [ 227 ] Motor Verbal commands of voluntary movements [ 228 ] Motor Voluntary motor movement based on verbal commands [ 229 ] Language Pictured object naming Pronouncing a familiar written Japanese word Action verb generation during image presentation Spontaneous speech through continuous conversation [ 230 ] Motor Verbal commands of voluntary movements [ 231 ] Face recognition Show faces and ask for change in perception Look at objects and the presenter’s own faces to discriminate face related from object related responses [ 232 ] Motor Tapping Continuous movement of the upper limb [ 233 ] Visuospatial …”