Zygomatico-coronoid Bony Ankylosis Co-existing with Temporo-mandibular Joint Ankylosis: Unusual Radiological Findings in a Post-traumatic Maxillofacial Patient

Zygomatico-coronoid ankylosis is an unusual event. Twenty-four cases have been reported so far in the English literature but the exact incidence might be more. In this case report, the management of a 30-year-old male patient with zygomatico-coronoid bony ankylosis is presented following road traffic accident.

Examination revealed moderate head injury with basal skull fracture, fractured mandible and dislocated right temporomandibular joint (TMJ). There were also fractured ribs, right femur and ankle fractures. Craniofacial CT scan showed compound fracture of the left parasymphysis of the mandible with supero-lateral fracture dislocation of the right mandibular condyle. He had mandibular fracture fixation with metal plates and screws and closed reduction of right TMJ. He was subsequently discharged with strict instructions on active jaw exercise. He was lost to follow up for 3 months and on re-presentation in the hospital, mouth opening was 1.4 cm. Repeated CT scan showed bony fusion involving the right zygomatic arch and the coronoid process.

Regarding treatment, surgical approach to the coronoid process was performed intraorally, however, because of persistent restricted mouth opening intraoperatively, a pre-auricular approach using the Bramley-Alkayat incision was used to assess the condyle in order to perform high condylectomy and utilize temporal muscle as inter-positional material.