Abstract
Navigation systems are surgical support devices that enhance surgical safety and reduce operating time by providing three-dimensional information about lesions. While commonly used in the intracranial, midfacial, and pharyngeal regions, their application to the mandible and surrounding tissues has been challenging. This report describes a case in which a navigation system was used to remove an injection needle that had strayed into the parapharyngeal space. The patient was a 31-year-old woman who had presented after a dental injection needle fractured during mandibular foramen block anesthesia at a local dental clinic. Panoramic X-ray and computed tomography (CT) images revealed a needle-shaped foreign body in the right parapharyngeal space, leading to a referral to our hospital. A surgical procedure using a navigation system under general anesthesia was planned to remove the foreign body. During CT imaging for registration, an opening aid was fabricated and fitted to the patient to reproduce the same opening position intraoperatively. During the operation, we found little error compared to the CT images. We identified and removed the foreign body, completing the operation without causing unnecessary tissue damage. This case demonstrates that navigation systems can be adapted to movable tissues around the mandible using a procedure similar to that employed here.
