Surgical navigation in cranio-maxillofacial surgery: an evaluation on a child with a cranio-facio-orbital tumour.

Surgical navigation, though well-established, is often associated with extra effort for both patient and surgeon, and with additional exposure to radiation as a result of the necessary extra imaging. Osteoblastoma is a benign bone tumour, malignant transformation of which is rare but possible, and so resection is indicated. The orbit with surrounding structures is a challenging region for accurate three-dimensional reconstruction. A virtual plan based on the patient's mirrored anatomy realised by intraoperative navigation can assist in achieving perfect results. An 8-year-old boy presented with a huge osteoblastoma of the frontal and temporal skull. The tumour had extracranial and intracranial parts, and reached into the orbital roof and the sphenoid and ethmoid bones. The ethmoid sinus was involved, the eye was displaced, and he had functional problems. Virtual planning and navigation were prepared without the need for any additional imaging. The tumour was resected through a coronal approach, and immediately reconstructed with an autologous calvarial split graft, designed and positioned under navigation with a preoperative plan that was based on the mirrored healthy side. Surgical navigation based on a virtual plan can achieve symmetrical results, particularly when dealing with complex three-dimensional anatomy. Navigation does not necessarily mean additional procedures or imaging. We think that virtual planning and navigation are useful for selected cases.