Extended reality in the changing landscape of cranial neurosurgery: Role of image fusions and connectomics in precision and safety

Recently, augmented reality (AR), virtual reality (VR) and mixed reality (MR) technologies, collectively termed Extended Reality (XR), have been adopted to support enhanced visualizations for neurosurgeons by augmenting the clinical environment with relevant digital content. These groundbreaking technologies, including connectomics, have been successfully integrated into neurosurgery as tools for preoperative rehearsals, surgical simulation, and intraoperative augmentation. Adaptation of XR within the surgical field has assisted neurosurgeons with preoperative planning using connectomics and anticipation of potential complications. XR enables neurosurgeons to explore operative fields from various angles and visualize hidden neurovascular anatomy, enhancing precision in keyhole approaches. It also addresses resident work hour restrictions and challenges like COVID-19, offering advanced training tools for novices and experts alike. Additionally, XR facilitates telecasting, patient education, remote telecollaboration, and helps bridge global educational gaps in neurosurgery, including credentialing and recertification. This paper outlays the conceptual differences between AR, VR, and MR, emphasizing the benefits and limitations of XR, along with the growing role of connectomics in micro-neurosurgery and endoscopic neurosurgery. The role of 2D versus 3D imaging, merger of preoperative versus real-time imaging, fusion of additional imaging data such as ICG, 5-ALA, or fluorescein angiography, and utilization of emerging technologies like Surgical Theater, QuickTome, etc. are highlighted. We also bring forth the pivotal role of visuo-spatial orientation of co-participants, apart from shared intentions and varied competence during the use of MR in neurosurgery. We explore the latest XR applications in neurosurgery and discuss exciting future directions, limitations, and ethical implications for the trailblazing technology.