Fluorescein-guided surgery for grade IV gliomas with a dedicated filter on the surgical microscope: preliminary results in 12 cases

Background Fluorescein is widely used as a fluorescent tracer for many applications. Its capability to accumulate in cerebral areas with blood-brain barrier damage makes it an ideal dye for intraoperative visualization of malignant gliomas (MG). We report our preliminary experience in fluorescein-guided removal of grade IV gliomas using a dedicated filter on the surgical microscope. Methods In September 2011 we started a prospective phase II trial (FLUOGLIO) to evaluate the safety and obtain initial indications about the efficacy of fluorescein-guided surgery for MG. Patients with suspected MG amenable to complete resection of contrast-enhancing areas were eligible to participate in this study. This report is based on a preliminary analysis of the results of 12 patients with grade IV gliomas out of 15 consecutive cases (age range 48–72 years) enrolled since September 2011. Fluorescein was injected intravenously (i.v.) after intubation (5–10 mg/kg). The tumor was removed using a microsurgical technique and fluorescence visualization by BLU 400 or YELLOW 560 filters on a Pentero microscope (Carl Zeiss, Germany). The study was approved by our ethics committee and registered on the European Regulatory Authorities website (EudraCT no. 2011-002527-18). Results Histological analysis confirmed grade IV gliomas in 12/15 cases. Median preoperative tumor volume was 33.15 cm 3 (9.6–87.8 cm 3 ). No adverse reaction related to the administration of fluorescein was registered. Contrast-enhanced tumor was completely removed in 75 % of the patients. Conclusion This preliminary analysis suggested that the use of intravenous fluorescein during surgery on grade IV gliomas is safe and allows a high rate of complete resection of contrast-enhanced tumor at the early postoperative MRI.