Exoscopic Versus Microscopic Surgery in 5-ALA Guided Resection of High Grade Gliomas

Background: Glioma surgery was remarkably renewed in the past 2 decades, with improved safety and limited but yet improved life expectations. Fluorescence-guided resection of high-grade gliomas (HGG) plays a central role in this sense, by allowing higher degrees of extent of resection (EOR). The introduction of the exoscopic guided surgery may be considered an implementation for fluorescence techniques over the traditional microscopes. We present the application and the advantages of the exoscopic guided surgery compared to the microscopic surgery in tumor resection guided by 5-ALA fluorescence in patients with HGG. Methods: ten consecutive patients underwent a surgery for HGG resection. The surgery was performed via an exoscopic-guided procedure (Olympus Orbeye) and after oral administration of Gliolan 5 hours before the procedure. During surgery, the procedure was shifted to microscope (Kinevo 900, Zeiss) view. The intensity of the fluorescence under the two different was subjectively measured in different picture samples during the surgery in a 1 to 5 (from minimum to maximum) scale. The brightness of the surgical field and the detailing of the anatomy were also analyzed comparatively. Results: among the ten patients the histopathological diagnosis was an high grade glioma in all cases. In 9 cases was possible to achieve the gross total resection. There was no perioperative mortality. The median fluorescence intensity, on a scale of 15, was 4.5 in the exoscope group and 3.5 in the microscope group (p0.01). Conclusions: The exoscopic guided surgery adds advantages to the traditional fluorescence- guided surgery with 5-aminolevulinic acid. Beyond the important advantage of low cost and the possibility to perform collaborative surgeries, it adds a plain and continuous visualization of the tumor and the surgical field in the fluorescence guided glioma surgery compared to the microscopic guided one.