Application and Outcomes of Indocyanine Green in Endoscopic Transsphenoidal Surgery for Functional Pituitary Tumors: A Literature Review.

Abstract

<b>Introduction:</b> Functional pituitary tumors (FPT) are hormone-producing adenomas that present distinct surgical difficulties, primarily because they are often microadenomas and require total removal to restore normal hormone levels. Distinguishing these tumors from healthy pituitary tissue during endoscopic transsphenoidal surgery can be challenging. Indocyanine green (ICG) fluorescence has shown promise as a technique to enhance visualization during surgery; however, its use in FPTs remains poorly defined. This literature review aims to evaluate the use of ICG in endoscopic transsphenoidal surgery for adult functional pituitary tumors. The primary focus is on assessing complete tumor resection, biochemical remission, and tumor differentiation from normal tissue after ICG use. Secondary goals include reviewing different ICG administration methods. <b>Methods:</b> We developed a search strategy to perform a systematic literature search across multiple databases with a set of MeSH terms and keywords on the OVID platform. In addition, we conducted a manual literature search by reviewing the reference lists of the studies included. After this, the relevant search results were uploaded to COVIDENCE for systematic management of the screening process by two reviewers. Articles that met our inclusion criteria were then selected for data extraction. <b>Results:</b> The initial search results gave 319 studies, of which 10 met the inclusion criteria after going through various screening phases. These were then included in the final analysis, consisting of 55 adult FPT cases. The majority of studies reported successful differentiation between tumor and normal pituitary tissue, with ICG fluorescence facilitating complete tumor resection and subsequent biochemical remission. Our review also identified two primary ICG administration techniques: low-dose intraoperative injection and high-dose preoperative administration. <b>Conclusion:</b> Findings from our study indicate that ICG fluorescence is a clinically effective tool for enhancing tumor visualization during endoscopic transsphenoidal surgery in adult FPT patients. Both low-dose intraoperative and high-dose preoperative ICG administration techniques showed promising outcomes in improving surgical precision. Having said that, further research, with larger comparative studies and the development of a standardized protocol, is required to optimize ICG use in FPTs as well as to address the variability in fluorescence intensity observed among different FPT subtypes.