Enlightening the invisible: Applications, limits and perspectives of intraoperative fluorescence in neurosurgery

The introduction of intraoperative fluorophores represented a significant advancement in neurosurgical practice. Nowadays they found different applications: in oncology to improve the visualization of tumoral tissue and optimize resection rates and in vascular neurosurgery to assess the exclusion of vascular malformations or the permeability of bypasses, with real-time intraoperative evaluations. A comprehensive knowledge of how fluorophores work is crucial to maximize their benefits and to incorporate them into daily neurosurgical practice. We would like to revise here their applications and clinical relevance. A focused literature review of relevant articles dealing with the versatile applications of fluorophores in neurosurgery was performed. The fundamental mechanisms of action of intraoperative fluorophores are enlightened, examining their interactions with target tissues and the principles driving fluorescence-guided surgery. The clinical applications of the principal fluorophores, namely fluorescein sodium, 5-ALA and indocyanine green, are detailed, in regards to the management of vascular malformations, brain tumors and pathologies treated through endoscopic endonasal approaches. Future perspective dealing with the development of new technologies or of new molecules are discussed. By critically assessing the efficacy and applications of the different fluorophores, as well as charting their potential future uses, this paper seeks to guide clinicians in their practice and provide insights for driving innovation and progress in fluorescence-based surgery and research. •Fluorophores maximize tumor removal and improve outcomes of vascular malformations.•FNa and ICG videoangiography have complementary advantages.•5-ALA is the gold standard for fluorescence-guided surgery for high-grade gliomas.•FNa may be a valid alternative to 5-ALA for glioma surgery and for other tumors.•FNa and ICG may be useful tools in performing endoscopic endonasal procedures.