A Fully Immersive, Open-Source Virtual Surgical Simulator for Skull Base Surgery

Background: Temporal bone requires both intricate understanding of three-dimensional microanatomy and precise surgical technique. Virtual surgical simulators have the potential to provide customizable and patient-specific practice. We present a fully immersive virtual temporal bone surgical simulator, as well as a relevant skull base use case to augment surgical training and facilitate preoperative planning.

Methods: The fully immersive virtual reality system (FIVRS) for skull base surgery was developed using asynchronous multi-body framework (AMBF), an open-source simulation environment. AMBF allows for the real-time simulation of surgical tools and patient tissue, with integration of haptic, sound, and visual feedback to the user ([Fig. 1]). For temporal bone procedures, we incorporated a PhantomOmni haptic device as a virtual drill. A CT scan of a patient with a facial schwannoma involving the labyrinthine segment and first genu was manually labeled ([Fig. 2]) and imported into FIVRS. Two surgeons performed five virtual drilling trials on this labeled CT.

Fig. 1 Hardware setup for the fully immersive virtual reality system.

Fig. 2 Axial (left) and coronal (right) views of left temporal bone CT scan. Inferior row shows manual color segmentations of structures. IAC, internal auditory canal; FN, facial nerve; SVN, superior vestibular nerve; CC, common crus; SSC, superior semicircular canal; TMJ, temporomandibular joint; ICA, internal carotid artery.

Results: FIVRS reliably modeled patient anatomy within its environment to simulate a middle cranial fossa approach for a patient with facial schwannoma involving the labyrinthine segment and first genu of the facial nerve. The internal auditory canal (IAC) was successfully unroofed, and the labyrinthine segment was successfully visualized for decompression without contacting the drill in all trials. The overall approach and characteristics of bone surrounding relevant anatomical structures as modeled by FIVRS was noted to reflect findings from this patient’s surgery.

Conclusion: FIVRS is an open-source platform that allows surgeons to virtually drill temporal bones with a haptic device. We present a patient case involving decompression of the facial nerve using FIVRS, which reflected the findings in this patient’s actual surgery. This system offers key benefits over traditional training methods, such as cadaveric and phantom models, as it provides cost-effective, repeatable, and patient-specific training. FIVRS has additional capabilities to suggest boundaries for dissection, display distances to critical structures, and overlay radiological views. Moreover, a variety of data are generated by the simulator including voxels removed, eye-tracking data, and drill stroke kinematics, which can be used for skill analysis. Future work on including these advanced features for skull base cases will be explored.

Fig. 3 Scenes in a representative FIVRS drilling trial. (Top) Middle cranial fossa approach to drilling the internal auditory canal (IAC). (Bottom) The bony covering of the IAC and the labyrinthine segment of the facial nerve (FN) for decompression. Bone above the superior semicircular canal (SSC) and superior vestibular nerve (SVN) was intentionally drilled for landmark visualization. INC, incus; MAL, malleus; TMJ, temporomandibular joint; ICA, internal carotid artery.

Publication History

Article published online:
07 February 2025