Rocuronium Induced Masseter Muscle Rigidity during Intubation in Patients with Dental Surgery

Masseter muscle rigidity (MMR), known as the ‘jaw of steel’, sometimes makes laryngoscope unusable due to the stiffness of the jaw. MMR during general anesthesia was previously considered as an early episode of malignant hyperthermia (MH). Generally, MMR occurs in the pediatric patients after induction with succinylcholine and volatile agents. However, MMR following the administration of non-depolarizing muscle relaxants is uncommon, although described in some reports. We report a case of 62-year-old male patient which developed MMR following intravenous administration of rocuronium during induction of anesthesia. Our patient was not found to be vulnerable to MH. Although fiberoptic nasotracheal intubation had been successfully performed in our case, an unanticipated difficult airway due to MMR can be experienced at any time. Therefore, we should be aware that, although rare, MMR can occur after using non-depolarizing muscle relaxant. Additionally, in case of any incident of MMR, anesthesiologists need to recognize the management of a difficult airway and to maintain adequate oxygenation in a variety of methods according to a difficult airway algorithm.