Neuronavigation is integral to modern neurosurgery. Clinical studies demonstrate its effectiveness. The primary tracking modalities in neurosurgical navigation are optical tracking systems (OTS) and electromagnetic tracking systems (EMTS). OTS remains the gold standard due to its accuracy and reliability. However, inherent inaccuracies due to brain deformation and image resolution and tool calibration and registration errors can impact overall accuracy significantly, which differs from the system-declared accuracy. Augmented reality (AR) technologies solve traditional navigation challenges by integrating virtual information with the patient’s anatomy, enhancing the surgeon’s focus and cognitive load management. Head-mounted displays (HMDs) offer ergonomic benefits, although most AR-based neuronavigation studies have been limited to proof-of-concept trials. This study aims to evaluate VOSTARS, a novel hybrid video and optical see-through HMD designed for precision surgery, specifically in neurosurgical oncology for targeting supratentorial tumors. Previous in-vitro studies using patient-specific phantoms have shown promising results, with high accuracy in real-to-virtual target visualization and craniotomy trajectory tracing. With this work, we further assessed VOSTARS’ targeting accuracy within a realistic neurosurgery clinical workflow and compared its performance to the commercial StealthStation ® system on a patient-specific phantom. Our results demonstrate that users achieved the same median accuracy, 2 mm (IQR: 1 mm), over 60 measurements with both VOSTARS and the StealthStation ® with no statistically significant difference between the systems, confirming the non-inferiority of the VOSTARS platform compared to a commercial optical tracking-based surgical navigator.

This study explores and preliminarily validates an online calibration method for Augmented Reality Optical See-Through Head-Mounted Displays. One of the major obstacles with those devices concerns the complexity and the unreliability of the calibration procedures for a correct virtual-to-real alignment, a key aspect of medical and industrial settings. Specific simplified procedures calibrate Commercial Optical See-Through devices, but these are mainly based on the adjustment of the single degree of freedom associated with the user's interpupillary distance. The presented work aims to provide a calibration method that can improve the performance and the accuracy of the user with precise control of the rendering cameras intrinsic and extrinsic parameters on the top of the device's default calibration system. The study was carried out using Microsoft HoloLens 2, which is one of the most advanced Optical See-Through Head-Mounted Displays, and we asked users to complete a targeting task within their peripersonal space after calibrating the device. Preliminary results show that the proposed method improves the alignment task by approximately 50 % in terms of mean error and by approximately 35 % in terms of maximum error.