Comparison of Fluorescein-INtra-VItal Microscopy Versus Conventional Frozen Section Diagnosis for intraOperative Histopathological Evaluation

In neurosurgery, intraoperative histopathological frozen section analysis (cryosection) offers a crucial tool for the rapid assessment of tumor entity and dignity and the creation of tumor-free resection margins. The method, however, remains unreliable and time-consuming, sometimes prolonging surgical times and demonstrating diagnostic accuracy for frozen section in glioma ranging from 78.4% to 95% in comparison to the final histopathology, depending on the technique used.2,3 To combat these shortcomings, another promising adjunct was developed in the form of intraoperative dye-dependent in-vivo microscopy, for which there has been little scientific evidence so far, with only a few recent studies exploring its utility, safety and general applicability. The theoretical idea of the technique in principle is to allow for histopathological assessment of tumor tissue in-vivo without the need for time-consuming fixation and transport of resected tissue biopsies, aiming for a so-called in-situ digital biopsy and thereby substantially improving operative precision and surgical times. It stands to reason that the benefit in visualization provided by fluorescein staining may further be driven through in-vivo microscopy. Altogether, with the use of fluorescein sodium in in-vivo microscopy, the operating surgeon may in the future inspect supposedly malignant fluorescent tissue first-hand, evaluate it for tumorous cells in real-time and adjust their resection strategy in a far more immediate fashion.