Practical Use of Mixed Reality for Transfacial Pinning in Monobloc Advancement for Syndromic Craniosynostosis

Mixed reality (MR) enables real-time overlay of virtual anatomic structures in the surgical field and has potential applications in craniofacial surgeries. Although early monobloc advancements have benefited from transfacial pinning, the technique remains challenging owing to the limited safe insertion area and orbital injury risk. The authors processed DICOM-format computed tomography images for bone segmentation and added a rod representing the optimal pin insertion trajectory. Then, the authors imported the final 3-dimensional models into HoloLens 2, an MR device. During surgery, after a bicoronal incision, the hologram was manually aligned with the skull based on anatomic landmarks, and transfacial pinning was guided along the virtual rod. This system allowed real-time confirmation of the entry point and insertion trajectory, resulting in accurate pin placement and a minimised risk of orbital penetration. MR-assisted transfacial pinning enhances surgical safety, reduces procedural stress, and holds promise for broad applications in craniofacial surgery and surgical education.