AWAKE SURGERY DURING 5-ALA HIGH GRADE GLIOMA FLUORESECNCE GUIDED RESECTION

Abstract

Introduction Awake surgery (AS) is currently the gold standard for low-grade glioma located in language brain areas to provide patients with the best prognosis with a high quality of life. A recent meta-analysis by Gerritsen et all (2019) also suggests that AS with direct cortical stimulation for high grade gliomas (HGG) provides a better outcome. Direct cortical stimulation and subcortical mapping during AS allows the surgeon to detect regions of the cortex and white matter tracts involved in specific functions of language, semantics, syntax, phonetics, or phonology. 5-ALA fluorescence-guided tumor resection is a technique that offers the advantage of better delineating high-grade glioma, increasing the chance of achieving gross total tumor resection, improving overall survival. 5-ALA is a metabolic tracer with a risk of photosensitisation and for 48 hours after administration the patient must be kept in a dark environment avoiding the risk of skin reactions. For this reason, during the operation including in the awake phase we have to keep the same low light exposure conditions, which could sometimes pose some difficulties for the operating team. Material and Methods We present a case operated in MedLife Polisano Hospital in May 2023, for frontal HGG, using AC together with 5-ALA fluorescence. The patient was evaluated preoperatively with MRI, MPRAGE contrast and DTI tractography, which was fused to the navigation system during surgery. The operation was performed with asleep-awakeasleep technique and in the awake phase we used the Boston test for naming, specific questions and calculation tests with direct cortical stimulation by the Penfield bipolar technique and monopolar subcortical mapping with the Raabe suction probe, adapted to our Natus Medical intraoperative monitoring system. Surgery was performed in semi-dark conditions with a tablet, turning on dim light tunning. Results In the awake phase we obtained speech arrest, semantic and phonological paraphrases, which allowed us to determine the brain areas, cortical and subcortical regions, involved in language functions. Thus we performed a total tumor resection with language-preserving. There were no incidents during surgery and the patient was discharged in good condition on the 5th postoperative day. Conclusions Brain tumor surgery is multimodal, using many tools and techniques. The use of AS together with 5-ALA fluorescence-induced resection is safe and provides the prerequisites to achieve gross total tumor resection while preserving language functions.

Keywords

• glioblastoma
• awake surgery
• fluorescence guided surgery