Hybrid optical and electromagnetic navigation for mandibular angle osteotomy

Surgical navigation systems are extensively employed to enhance the accuracy and safety of traditional surgeries. However, current single-mode systems, using either optical navigation or electromagnetic (EM) navigation, suffer from either occlusion or magnetic interference when simultaneously tracking the mandible and surgical saw in mandibular angle osteotomy (MAO). To resolve this, we propose a hybrid optical and EM navigation system (HOENS), utilizing optical navigation to track the surgical saw and EM navigation to track the mandible. A distance-based automatic hybrid navigation strategy is introduced to integrate both navigation approaches, leveraging the strengths of each. We conducted experiments with mandible phantoms to verify the effectiveness and accuracy of HONES. Results demonstrate that under laboratory conditions, with some nearby metallic interference, HOENS achieves an average hybrid navigation accuracy below 2 mm. Further evaluation of magnetic interference from the surgical saw on the EM sensor validated the necessity of our hybrid navigation strategy. Finally, we conducted osteotomy experiments on the mandible phantoms, where HOENS operated normally and provided precise visual guidance, with an average setup time of less than 20 min. Consequently, HOENS is feasible and effective for assisting surgeons in MAO, meeting clinical accuracy requirements, and shows promising potential for future clinical applications.