Postoperative temporomandibular joint dislocation reduced by the syringe technique

A young adult female, otherwise well with no relevant history and who consented to publication of this report, presented for a minor procedure under general anaesthesia without neuromuscular blockade. Preoperative assessment was performed on the day of surgery. She had previously had an uneventful anaesthetic for a past surgery. The patient had no other past medical history. She did not take any regular medication. On airway assessment, it was noted that she had a slightly small mouth opening, a Mallampati score of 2 and good neck mobility. Her body mass index was 25 kg/m², and she was categorised as American Society of Anesthesiologists physical status class I. The patient gave informed consent for general anaesthesia.

In theatre, routine monitoring was attached. The patient was given midazolam 1 mg and fentanyl 50 μg, and anaesthesia was induced with propofol 200 mg. A jaw thrust was performed by the anaesthetic technician, and an i-gel® (Intersurgical Ltd, Wokingham, UK) laryngeal mask airway (LMA) was inserted by the consultant anaesthetist successfully on their first attempt. No complications were noted. Ventilation was successful. Anaesthesia was maintained with sevoflurane. No muscle relaxants were given. The duration of the surgical procedure was approximately 15 minutes.

Following completion of the surgery, the sevoflurane was turned off. Once the patient was spontaneously breathing, the LMA was removed in theatre, and the patient taken to the post-anaesthesia care unit (PACU). After the patient awoke in the PACU, it was noted that her jaw was locked open and that she was unable to close her mouth. The patient was able to indicate that there was something wrong on her left side. A left-sided anterior temporomandibular joint (TMJ) dislocation was immediately suspected. Diagnosis was made clinically, with no investigations performed. The ‘syringe technique’ was suggested and then performed by an emergency medicine trainee, and the dislocation was successfully reduced. ¹ Intraoral jaw manipulation was also considered and would have been the next step had the syringe technique failed. However, this would have potentially required intravenous analgesia and sedation. The patient had no complaints of pain throughout the reduction, throughout her time in PACU or at a phone call follow-up three months following the event.

The syringe technique was described in an emergency department setting by Gorchynski et al. in 2014. The technique appears to be well tolerated by patients and requires no procedural sedation or intravenous analgesia. ¹ To the authors’ knowledge, it has not previously been used in the postoperative setting. We provide a brief description of the syringe technique, as it may not be familiar to many anaesthetists. The technique is performed by placing a five or ten ml syringe between the patient’s posterior upper and lower molars or gums on the affected side. The patient is asked to bite down gently, grasp the syringe between their teeth and then to roll the syringe back and forth using their teeth. ¹ In Gorchynski et al.’s prospective study, the syringe technique achieved a 97% success rate (30/31 patients) in reducing anterior non-traumatic TMJ dislocation in the emergency department, with the majority (77%) of cases successfully reduced in less than one minute. ¹

Jaw dislocation following general anaesthesia is a rare but well-described complication.^2–5 Traditional TMJ reduction techniques require manual intraoral or extraoral manipulation of the jaw by the anaesthetist, which puts them at risk of bite injury. ¹ , ⁶ In this case, we found the syringe technique to be a simple, fast and effective technique to reduce a postoperative anterior TMJ dislocation safely. We would recommend that the syringe technique be attempted for up to five minutes to reduce anterior TMJ dislocation in the awake patient in the postoperative setting prior to consideration of manual intraoral or extraoral jaw manipulation.