[A Difficult Airway after Anesthetic Induction in a Patient with Masticatory Muscle Tendon-Aponeurosis Hyperplasia].

We present a case of masticatory muscle tendon- aponeurosis hyperplasia in a patient who underwent general anesthesia for gynecologic surgery. The patient's square-shaped mandible was noticed during preoperative assessment by an anesthesiologist. Further investigation revealed masticatory muscle tendon- aponeurosis hyperplasia. Anesthetic induction agents were administered, and facemask ventilation was initi- ated easily. As the anesthesiologist had predicted, the patient's mouth opening was reduced after administration of muscle relaxants, and keeping her mouth open was more difficult than when she was conscious. Nasotracheal intubation was performed successfully using a bronchoscope. Patients with muscle tendon- aponeurosis hyperplasia do not generally have associated pain, and do not know that they have a limited mouth opening. They are therefore sometimes unaware that they have the condition. Anesthesiologists need to predict that airway intubation will be difficult when the patient has a limited mouth opening associated with a square-shaped mandible.