Enabling Navigation and Augmented Reality in the Sitting Position in Posterior Fossa Surgery Using Intraoperative Ultrasound.

Simple Summary: Neuronavigation and microscope-based augmented reality are widely used in neurosurgery to support intraoperative orientation, preserve neurological function, and maximize the extent of resection. However, in the sitting position, navigation may not be accurate enough to fully exploit its potential due to brain deformations caused by gravity and brain shift. To ensure accurate navigation and augmented reality support, it is necessary to verify and update navigation regularly. Intraoperative ultrasound is an easy-to-use tool that can be used to verify accuracy and to generate real-time image data to update navigation without significantly interrupting the surgical workflow. This can be achieved by outlining the lesion within the data set or by rigidly co-registering preoperative and intraoperative data to update and enable navigation and augmented reality support. In this study, image-based co-registration improved the navigation accuracy, making intraoperative ultrasound useful for enabling navigation and augmented reality support during posterior fossa surgery in the sitting position. Despite its broad use in cranial and spinal surgery, navigation support and microscope-based augmented reality (AR) have not yet found their way into posterior fossa surgery in the sitting position. While this position offers surgical benefits, navigation accuracy and thereof the use of navigation itself seems limited. Intraoperative ultrasound (iUS) can be applied at any time during surgery, delivering real-time images that can be used for accuracy verification and navigation updates. Within this study, its applicability in the sitting position was assessed. Data from 15 patients with lesions within the posterior fossa who underwent magnetic resonance imaging (MRI)-based navigation-supported surgery in the sitting position were retrospectively analyzed using the standard reference array and new rigid image-based MRI-iUS co-registration. The navigation accuracy was evaluated based on the spatial overlap of the outlined lesions and the distance between the corresponding landmarks in both data sets, respectively. Image-based co-registration significantly improved (p < 0.001) the spatial overlap of the outlined lesion (0.42 ± 0.30 vs. 0.65 ± 0.23) and significantly reduced (p < 0.001) the distance between the corresponding landmarks (8.69 ± 6.23 mm vs. 3.19 ± 2.73 mm), allowing for the sufficient use of navigation and AR support. Navigated iUS can therefore serve as an easy-to-use tool to enable navigation support for posterior fossa surgery in the sitting position. [ABSTRACT FROM AUTHOR]