Fluorescence guidance in skull base surgery: Applications and limitations - A systematic review

Abstract

Introduction: Intraoperative fluorescence guidance is a well-established surgical adjunct in high-grade glioma surgery. In contrast, the clinical use of such dyes and technology has been scarcely reported in skull base surgery.

Research question: We aimed to systematically review the clinical applications of different fluorophores in both open and endonasal skull base surgery.

Material and methods: We performed a systematic review and discussed the current literature on fluorescence guidance in skull base surgery.

Results: After a comprehensive literature search, 77 articles on skull base fluorescence guidance were evaluated. A qualitative analysis of the articles is presented, discussing clinical indications and current controversies. The use of intrathecal fluorescein was the most frequently reported in the literature. Beyond that, 5-ALA and ICG were two other fluorescent dyes most extensively discussed, with some experimental fluorophore applications in skull base surgery.

Discussion and conclusion: Intraoperative fluorescence imaging can serve as an adjunct technology in skull base surgery. The scope of initial indications of these fluorophores has expanded beyond malignant glioma resection alone. We discuss current use and controversies and present an extensive overview of additional indications for fluorescence imaging in skull base pathologies. Further quantitative studies will be needed in the future, focusing on tissue selectivity and time-dependency of the different fluorophores currently commercially available, as well as the development of new compounds to expand applications and facilitate skull base surgeries.

Keywords: 5-ALA; Endoscopic endonasal surgery; Fluorescein; Fluorescence-guided resection; Indocyanine-green; Skull base tumors.

Fig. 1

– Endoscopic endonasal view of intrathecal applied fluorescein demonstrating an anterior skull base defect in a young female patient with spontaneous rhinoliquorrhea.

Fig. 2

A case of ICG fluorescence after endoscopic endonasal resection of intrasellar PitNET. A single dose 25 mg was given upon completing sphenoidal step of the procedure. In (A) endoscopic view after surgical resection shows the pituitary gland dislocated laterally and posteriorly. In (B) the ICG endoscopic view show differences in the fluorescence of the gland caused by different degrees of compression by the tumor. In (C) measurement of ICG fluorescence representing when the maximum and minimum blue color values were reached in the pituitary gland, with attached screenshots from the measurements generated using ImageJ software. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3

(A) axial, (B) coronal, and (C) sagittal MRI post-contrast images of a pituitary macroadenoma where the gland is pushed to the right side and is covering the sellar face. (D) shows opening of the dura and underlying hyperfluorescent pituitary gland. (E) shows sectioning of the gland to reveal the underlying hypofluorescentwadenoma. (F) shows a cruciate incision of the pituitary gland and the underlying hypofluorescent adenoma.

Fig. 4

A case of a recurrent chordoma in which a nasoseptal flap has been reutilized. In (A) normal endoscopic mode shows the proximal portion^◄ of the flap and the distal portion^●of the flap. In (B) shows the ICG endoscopic view where the distal portion^●is hypofluorescent in comparison to the proximal portion^◄. (C) shows a case of pituitary microadenoma with the beginning of the ICG fluorescence in the Internal carotid artery * on both sides. (D) shows a case of resected tuberculum sellae meningioma and the underlying optic nerve, left Internal carotid artery▼, and the superior hypophyseal artery ^▲.