Augmented Reality Navigation for Cortical Surface Mapping and Tractography Visualization During Epilepsy Surgery

Introduction: Surgical resection of the seizure onset zone can provide high rates of seizure freedom in patients with epilepsy, but carries a risk of neurologic deficit when the epileptogenic lesion is in close proximity to eloquent regions. Traditionally, cortical surface mapping has been done using 2D neuronavigation and electrocorticography. Here we report the first known case series using Augmented Reality (AR) navigation for intraoperative cortical surface mapping and tractography visualization during epilepsy surgery.

Methods: An AR navigation platform was developed using a commercially available head-mounted display (Microsoft HoloLens 2). Preoperative imaging data (MRI, DTI, & CT) was segmented and registered intraoperatively to the patient using a stylus and anatomic landmarks. AR navigation was used to visualize fiber tracts, cortical structures, and vasculature directly on the patient throughout the surgical procedure. AR navigation accuracy was compared to traditional 2D neuronavigation and phase reversal electrocorticography.

Results: AR navigation was used in 3 surgical epilepsy cases (age range: 16-26 years). In two cases, AR navigation was used for pre-central gyrus, cortical vasculature, and corticospinal tract (CST) visualization; one for the resection of the seizure onset zone in the SMA/pre-SMA region as defined by stereoelectroencephalography (SEEG), and the other for resection of an AVM near the post-central gyrus. In these cases, AR navigation was also used for dural sinus visualization. In the third case, AR was used to visualize the optic tract during a right anterior temporal lobectomy. The seizure onset zone was localized via SEEG as being directly adjacent to the optic tract. All 3 cases were seizure free with no significant neurological deficits at last follow-up.

Conclusion : AR navigation was found to be accurate when compared to traditional 2D neuronavigation and phase reversal electrocorticography. Intraoperatively, it has provided an improved method of cortical surface neuronavigation that provides the surgeon with increased 3D spatial information.