Preclinical Application of Augmented Reality in Pediatric Craniofacial Surgery: An Accuracy Study

Abstract

Background: Augmented reality (AR) allows the overlapping and integration of virtual information with the real environment. The camera of the AR device reads the object and integrates the virtual data. It has been widely applied to medical and surgical sciences in recent years and has the potential to enhance intraoperative navigation.

Materials and methods: In this study, the authors aim to assess the accuracy of AR guidance when using the commercial HoloLens 2 head-mounted display (HMD) in pediatric craniofacial surgery. The Authors selected fronto-orbital remodeling (FOR) as the procedure to test (specifically, frontal osteotomy and nasal osteotomy were considered). Six people (three surgeons and three engineers) were recruited to perform the osteotomies on a 3D printed stereolithographic model under the guidance of AR. By means of calibrated CAD/CAM cutting guides with different grooves, the authors measured the accuracy of the osteotomies that were performed. We tested accuracy levels of ±1.5 mm, ±1 mm, and ±0.5 mm.

Results: With the HoloLens 2, the majority of the individuals involved were able to successfully trace the trajectories of the frontal and nasal osteotomies with an accuracy level of ±1.5 mm. Additionally, 80% were able to achieve an accuracy level of ±1 mm when performing a nasal osteotomy, and 52% were able to achieve an accuracy level of ±1 mm when performing a frontal osteotomy, while 61% were able to achieve an accuracy level of ±0.5 mm when performing a nasal osteotomy, and 33% were able to achieve an accuracy level of ±0.5 mm when performing a frontal osteotomy.

Conclusions: despite this being an in vitro study, the authors reported encouraging results for the prospective use of AR on actual patients.

Keywords: augmented reality; computer-assisted surgery; craniofacial surgery; head and neck surgery.

Figure 1

Development phase: (a) from CT scan to virtual content preparation; the virtual 3D skull model was also 3Dprinted to obtain a patient-specific phantom; (b) Unity software interface used for AR application development; (c) the planned osteotomy lines displayed in AR with HoloLens 2 smart glasses.

Figure 2

On the left, the planned osteotomies for the fronto-orbital bandeau of the Fronto Orbital Remodeling (FOR) on the right, the 3D printed cutting guides with calibrated grooves for both osteotomies.