Replacement of temporomandibular condylar head in a patient suffering from ankylosing spondylitis with severe ankylosis of the temporomandibular joints and whole spine

Abstract Bilateral prosthetic replacement of the condylar head was performed via a transparotid approach without adverse events in a 42-year-old man suffering from ankylosing spondylitis with severe ankylosis of both temporomandibular joints and the whole spine. He was diagnosed with ankylosing spondylitis 7 years previously, and trismus was noted at the time of diagnosis. He also had a 28-year history of psoriasis vulgaris. He could not open his mouth and had a very limited range of motion in the spine, which was fixed in a kyphosis position. We encountered two general difficulties when attempting to perform condylar replacement. First, because of ankylosis of the whole spine and decreased mechanical bone strength, the risk of an intraoperative spinal injury was not negligible. We prevented this by repeated preoperative simulations and optimization of the intraoperative position with the cooperation of the medical staff. Second, because of the limited range of motion in the whole spine and temporomandibular joints, the operative field was not guaranteed, so intraoral and posterior approaches could not be performed. The extraoral transparotid approach was used in this patient, despite a risk of facial nerve paralysis. We achieved a final mouth-opening capacity of 45 mm without complications.