Advancements in Neurosurgical Intraoperative Histology

Abstract

Despite their relatively low incidence globally, central nervous system (CNS) tumors remain amongst the most lethal cancers, with only a few other malignancies surpassing them in 5-year mortality rates. Treatment decisions for brain tumors heavily rely on histopathological analysis, particularly intraoperatively, to guide surgical interventions and optimize patient outcomes. Frozen sectioning has emerged as a vital intraoperative technique, allowing for highly accurate, rapid analysis of tissue samples, although it poses challenges regarding interpretive errors and tissue distortion. Raman histology, based on Raman spectroscopy, has shown great promise in providing label-free, molecular information for accurate intraoperative diagnosis, aiding in tumor resection and the identification of neurodegenerative disease. Techniques including Stimulated Raman Scattering (SRS), Coherent Anti-Stokes Raman Scattering (CARS), Surface-Enhanced Raman Scattering (SERS), and Tip-Enhanced Raman Scattering (TERS) have profoundly enhanced the speed and resolution of Raman imaging. Similarly, Confocal Laser Endomicroscopy (CLE) allows for real-time imaging and the rapid intraoperative histologic evaluation of specimens. While CLE is primarily utilized in gastrointestinal procedures, its application in neurosurgery is promising, particularly in the context of gliomas and meningiomas. This review focuses on discussing the immense progress in intraoperative histology within neurosurgery and provides insight into the impact of these advancements on enhancing patient outcomes.

Keywords: Raman histology; cytologic preparations; deep neural networks; digital histopathological assessment; frozen sectioning.

Figure 1

Schematic representation of the long and tedious histopathology process. The patients need to undergo initial scanning to identify the tumor. This is followed by a sample section which further undergoes multiple processing steps, taking a longer time, and needs to be confirmed by a neuropathologist which increases the chances of error. An error or partial removal of a tumor leads to invasive surgery, again affecting the health and quality of life of the patient (created with Biorender.com). Copyright © 2023 The Authors. CS Omega published by American Chemical Society [13].

Figure 2

Confocal Laser Microscopy in vivo Convivo case (Besta Neurological Institute, Milan, Italy). (A). The confocal probe is dressed with its appropriate sterile sheath and used directly on the cerebral surface. (B). Preoperative magnetic resonance with contrast administration images loaded on the neuronavigation system (Stealth S8-Medtronic) of a right frontal parasagittal anaplastic oligodendroglioma, IDH mutant (WHO grade III). (C). Intraoperative view of fluorescein-guided removal of the tumor under YELLOW560 filter activation on a Pentero microscope (Carl Zeiss Meditec). (D). Convivo in vivo image taken at the center of the tumor showing tumor cells along with typical perineural satellitosis (small arrows), which can be easily found on a relative histopathological image as well (hematoxylin and eosin, big arrow, (E)). Copyright© 2021 The Authors. Journal of Clinical Medicine published by MDPI, Basel, Switzerland [60].