Fluorescence Guided Focal Cortical Dysplasia Surgery

Epilepsy is one of the most common neurological disorders, with one of the highest morbidity rates of all diseases. Despite the development of new anticonvulsant drugs, around a third of patients suffer from drug-resistant epilepsy (RPE). The onset of RPE can be lengthy, prolonging the period during which affected patients live with seizures that have a negative impact on their quality of life. Epilepsy surgery can be a curative treatment, and can enable anticonvulsant medication to be discontinued, optimizing quality of life and cognitive development. In addition, as it has been shown that the prolonged duration of epilepsy prior to surgery has an impact on the occurrence of postoperative seizures, early surgery is increasingly being considered. Focal cortical dysplasia (FCD) is the leading cause of focal lesional epilepsy and is generally drug-resistant. Good postoperative seizure results after surgical resection are strongly linked to complete resection of the dysplastic tissue. Consequently, accurate localization and precise delineation of FCD lesions are crucial during surgery. Currently, the extent of surgical resection is based primarily on preoperative examination, as the macroscopic appearance of dysplastic tissue does not differ from normal cortex. The various intraoperative techniques available to improve the quality of excision (neuronavigation, ultrasound, intraoperative MRI and intraoperative guidance by fluorescence microscopy) all have their limitations. In this context, new intraoperative tools are needed to help the neurosurgeon delineate lesions during surgery. Intraoperative fluorescence spectroscopy is used for surgical guidance of gliomas and other brain pathologies, and has demonstrated its ability to characterize pathological tissues. DCFs exhibit metabolic differences that can also be detected by 5-amino-levulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence intraoperatively. Indeed, in some patients who underwent surgery after