Protoporphyrin-IX Fluorescence in Skull Base Meningiomas’ Resection

• Published in: Journal of Neurological Surgery Part B: Skull Base Vol. 74; no. S 01
• Main Authors: ManHon, Tang, Goodman, Carol, Moseley, Harry, Eljamel, Sam
• Format: Conference Proceeding Journal Article
• Language: English
• Published: 16.03.2013
• ISSN: 2193-6331; 2193-634X
• DOI: 10.1055/s-0033-1336196

Introduction: Meningiomas arise from arachnoid cap cells that surround and adhere to the dura mater. Meningiomas comprise 13-30% of primary intracranial tumors and are only less frequent than intracranial gliomas. They can occur anywhere in the cranium and the spine, and removal of skull base meningiomas is challenging. We explored the use of fluorescence to guide intracranial meningiomas’ resection. Methods: Twenty-nine consecutive lesions with MRI differential of meningiomas were included in this analysis, including 17 supratentorial, 10 infratentorial, and 1 thoracic. Twenty-three were women, the mean age was 55.4 years, and the final diagnosis was meningioma in 21 (72.4%). All these patients received 1.5 g 5-aminolevulinic acid (ALA) orally approximately 3 hours before surgery. Surgical resection was aided by using the blue light of the microscope (Pentero, Zeiss, Germany). The fluorescence was graded into strong (very red fluorescent), faint (pink), and moderate (between red and pink). Results: Fluorescence was detected in 22 (78.6%), of which 20 were intracranial meningiomas. Strong fluorescence signal was observed in nine of all lesions (32%), all of which were intracranial meningiomas (45%). Moderate fluorescence was noted in seven lesions (25%), all of which were intracranial meningiomas (35%). Faint signal was observed in six (14.3%), four of which were meningiomas (20%). Seventeen of intracranial meningiomas were WHO grade I (85%) and three (15%) were grade II. Total excision (Simpson grade 1) was achieved in all meningiomas. There was no correlation between histological type, ALA dose, or time to fluorescence and the intensity of fluorescence. Only two patients developed significant drop in blood pressure (7.1%). Conclusion: Intracranial meningiomas fluoresce after oral ALA at a dose of 12-35 mg/kg body weight. ALA-induced fluorescence is safe and helpful in intracranial meningioma surgical resection.