mise à jour du
6 juin 2002
J Clin Anesth
Dislocation of the temporo-mandibular joint due to forceful yawning during induction with Propofol
 Alexander Avidan
Department of anesthesiology and critical care medecine, Hebrew University Hadassah Medical School, Jerusalem, Israel 
Bâillements et stomatologie
Yawning is often seen during induction of anesthesia with propofol. I report an episode of dislocation of the temporo-mandibular joint caused by forceful yawning during induction with propofol.
A 26-year-old, healthy (ASA physical status 1) woman was scheduled for aspiration of oocytes for in vitro fertilization. During the slow induction of anesthesia with propofol (AstraZeneca, London, UR) to a total dose of 2 mg/kg the patient yawned forcefully. During the procedure, the patient was breathing spontaneonsly through a facemask (70% nitrous oxide in oxygen), and at the end of surgery she was fully conscious. It was then noticed that her mouth was sliglitly opened (approximately 1 cm) and that she could not open, nor close it. Dislocation of the right teimporo-mandibular joint (TMJ) was the diagnosis. This was explained to the patient and she agreed to undergo reduction of the TMJ under anesthesia. After administration of 1 mg/kg propofol the jaw was easily reduced by pushing the mandible inferiorly and posterior. The patient wokeup within 1 to 2 minutes. She then complained about pain in the right TMJ. The rnouth opening was good with stable closure, and both TMJs were moving freely. A gauze bandage was applied around her face to prevent any further inadvertent wide mouth opening for the next 24 hours, and she was instructed to eat a soft diet only. Further follow-up was not necessary because the patient did not have any history of previous TMJ dislocation.
It is well known that forced volontary opening of the mouth (stich as yawning, laughing, or even passionate kissing) may lead to TMJ dislocation. Forced passive opening of the mouth (e.g. during larygoscopy.) inpatients with or without hypermobility of the TMJ may also lead to dislocation. Yawning during induction of anesthesia is frequently seen with propofol. The slow injection of propofol transforms the patient from the awake state through sedation to anesthesia. In the stage of sedation, forceful yawning may occur. The dislocation of the TMJ is caused by displacement oftlic mandibular head out of the glenoid fossa. Anterior dislocation, such as was seen in this case, is the most common presentation, where posterior, lateral, and superior dislocations are rarer and usually associated with coexistant fractures of the base of skull,mandible, or the glenoid fossa
Early reduction of the dislocatedjoint is important in reducing permanent sequelae. The goal is to bring thecondylar head down and around the articular eminence of the TMJ. This action is achieved by pushing the mandible inferiorely and posterioly and it can be performed while standing before or behind the patient: The lateral pterygoid muscle is the main muscle of involvement. Although the reduction may be performed while the patient is conscious, decrease of the muscle spasm facilitates the joint reduction and reduces the pain. This can be achicved with direct injection of local anesthetics into the muscle or under sedation. Totten and Zambito describe the use of propofol to reduce dislocated TMJ in two patients. It is interesting to note that in one patient the TMJ had to be reduced twice: the patient dislocated the TNJ a second time while yawning during propofol sedation alter the TMJ was reduced the first time. Although propofol is an excellent sedative drug, its use may be contraindicated in reducing TMJ dislocations. Forceful yawning during induction of anesthesia with propofol should be avoided.