Surgical Planning of Temporal Bone Skull Base Defects Using 3D Patient-Specific Models

The middle cranial fossa (MCF) approach provides exceptional exposure to the internal auditory canal, tegmen tympani, tegmen mastoideum, the petrous apex, the labyrinthine and tympanic segment of the facial nerve including the geniculate ganglion. The MCF approach is used for the resection of skull base tumors, repair of tegmen dehiscences with associated cerebrospinal fluid (CSF) leak and superior semicircular canal dehiscences. The MCF approach is a valuable yet technically challenging technique that is not without its challenges: the middle cranial fossa floor can be a featureless, flat, and smooth surface lacking clear and distinct landmarks. While the arcuate eminence has classically guided skull base surgeons to the location of the superior semicircular canal, it has been often described as being anterior, posterior or altogether absent. Furthermore, several cadaveric studies of the temporal bone have consistently described the unreliability of using the arcuate eminence as a substitute of the superior semicircular canal during topographic orientation. Thus, the lack of reliable and distinct anatomic landmarks that are consistent from patient to patient can present significant difficulties. Compounding the problem is the disparity in training programs that teach the MCF approach.

Augmented reality (AR) offers a new approach to overcome these anatomical, or lack of anatomical landmarks at the MCF. To address these limitations, we consider the effectiveness of three different forms of AR techniques in improving the surgeon’s localization of skull base disorders including tegmen defects and superior semicircular canal dehiscences.

Augmented reality (AR) techniques consisting of 3D images, hybrid-reality holographic superimposed images, and 3D models are compared with the traditional controls, standard CT and MRI images. By allowing the surgeon to visualize and interact with the area of interest in new dimensions, these innovative forms of visualization offer key insights into the anatomical landscape that are unclear or absent from traditional images. Additionally, AR offers the potential to overcome the need to look away from the surgical field as the superimposed hybrid-reality holographic images are incorporated into the surgical field. Ultimately, these visualizations have the potential to improve surgical outcomes in skull base disorders that employ the MCF approach.