[Application of computer-assisted navigation in oral and maxillofacial surgery: retrospective analysis of 104 consecutive cases].

Purpose: To evaluate the application of computer-assisted navigation system (CANS) in Oral and Maxillofacial Surgery.

Methods: One hundred and four patients were included in this study, including 34 with zygomatic-orbital-maxillary fracture, 27 with unilateral TMJ ankylosis, 29 with fibrous dysplasia, 9 with mandibular angle hypertropia, 3 with cartilage and bone tumors and 2 with facial foreign bodies. CT scan was performed and the data was saved as Dicom (digital imaging and communications in medicine) format. With preoperative planning and 3-dimensional simulation, normal anatomic structures of the affected side were created by superimposing and mirroring the unaffected side. The osteotomy lines, amount and range of resection, the reduction position of bony segments and the reconstruction morphology was determined and displayed. All surgeries were performed under the guidance of navigation system. The accuracy of navigation was evaluated by comparing the postoperative CT three-dimensional model with preoperative surgical planning.

Results: Through registration, an accurate match between the intra-operative anatomy and the CT images was achieved. With the guidance of navigation, anatomic structures and the position of surgical instruments were shown real-time on the screen. No complications occurred in all patients and the systematic error was within 1 mm. Good coincidence with preoperative planning was achieved for osteotomy lines, the amount of resection and reduction of fractures. The mean error between virtual and real results was (1.46±0.24) mm. All patients healed uneventfully and facial symmetry was improved.

Conclusions: With the ability of preoperative planning, surgical simulation and postoperative prediction, CANS shows its great value in improving the accuracy of oral and maxillofacial surgery, reducing trauma and restoring facial symmetry. It is regarded as a valuable and safe technique in this potentially complicated procedure.