Dr Stephen Gilmartin Emergency Registrar
Peer review: Dr Mehul Srivastava
Editor: Dr David McCreary
THE CASE
A 22-year-old female medical student attends the emergency department. She is unable to close her mouth after yawning in one of her biochemistry lectures. She is in some distress and is struggling to speak clearly.
You have seen many a bored medical student, so you are able to quickly diagnose a temporomandibular joint (TMJ) dislocation. Before we get down to the fun part of relocation let’s explore the background of this injury.
ANATOMY
The TMJ is a ginglymoarthroidal (yes, that's a real word) joint, this means it is made up of two joints, one moving in a hinge motion and the other in a gliding motion. The Condylar process articulates with the glenoid fossa and is cushioned by an articular disc.
HOW IS STABILITY NORMALLY MAINTAINED?
The synergistic movement of the joint’s dynamic stabilisers (pterygoid and masseter muscles) ensures the TMJ remains stable during opening and closing of the jaw.
Image 2: Anatomy of Pterygoid Muscles
Image 3: Anatomy of Masseter Muscles
DISLOCATION
Spontaneous anterior TMJ dislocation has a reported annual incidence of 5.3 per 1,000,000 patients who present to the emergency department (ED)(2). Dislocation is most commonly bilateral but can also be unilateral.
MECHANISM
When movement of the stabilising muscles becomes uncoordinated, this leads to an increased risk of TMJ dislocation. Dislocations can occur in any direction but anterior is by far the most common. This involves the condylar process moving anteriorly out of the fossa and sitting anterior to the articular eminence. Most dislocations occur spontaneously following yawning, eating seizures or intraoral procedures. Infrequently dislocations have an associated fracture.
REDUCTION
The optimal reduction technique will be safe and performed with appropriate analgesia and sedation. We will not discuss analgesia and sedation techniques here, instead we will focus on the reduction methods themselves. We would advise attempting the extraoral methods first (Methods 1 & 2 below) prior to attempting the intraoral method. This is for two reasons; the intraoral method is invasive and usually requires some level of sedation.
EXTRA-ORAL 1. Our first method was first described in 2007 by Chen et al(4). They reported a case series of seven patients who were all successfully reduced using this extraoral technique. They did not comment on success rates among all comers, time taken or any complications. This technique involves:
Sitting the patient upright with their head against a solid surface
Apply steady pressure with your thumb to the anterior ramus of the affected side.
With your other hand, you do two things.
First is to provide counter pressure with your thumb on the patient’s cheek.
The second is to apply an anterior and rotational force to the contralateral angle of the mandible with your fingertips.
You should feel a clunk. If it is a bilateral dislocation, you now perform the same procedure on the opposite side.
You can see a great video of an extra-oral method from AliEM here:
2. Our next extra-oral technique was described more recently (2014), the 'syringe technique':
Once again, the patient is placed in a comfortable seated position.
The clinician places a syringe between the posterior upper and lower molars on the affected side.
The patient is then instructed to gently bite down and grasp the syringe while rolling it back and forth in their mouth.
This should result in reduction after a few minutes.
The authors describe an impressive success rate of 97% (30/31), (the unsuccessful patient had no teeth!), 70% (24/31) were relocated in less than one minute with nil complications reported (5).
INTRA-ORAL METHOD
Finally, we have the traditional intra-oral method described in the textbooks. (Ed. - and the technique I use regularly as it works every time, sorry, novel-techniquers!):
Sitting the patient upright with their head against a solid surface. This is to avoid retraction away from the clinician.
While wearing gloves, the clinician places their thumbs into the patient’s mouth and applies pressure to the patient’s inferior molars
An inferior and anterior force is applied
Once you feel the condyle is disengaged you can apply posterior force to relocate.
You should feel a clunk and the patient will be immediately relieved.
A video of the traditional method can be seen here.
☝️ Editor's note: Practice Point Yes, this is putting your thumbs between the patient's molars so you want to have some gauze over your digits. My way of doing this is to put on a pair of gloves, put the gauze over your thumbs, and put a second pair of gloves over this. This prevents you having loose gauze floating around the patient's mouth and gives you more dexterity for performing the technique.
CASE CONCLUSION You relocate the TMJ using the extraoral technique. The patient is delighted and can now (carefully) sing your praises. Before she goes you advise her to avoid eating large or chewy foods for the next few days and to apply superior pressure to her chin when yawning. She asks does she require surgery and you reassure her that this is rarely warranted, and simple self-help techniques as described are more effective.
REFERENCES
Minye HM. Neuroplasticity and central sensitization in orofacial pain and TMD. OBM Neurobiol. 2020;4(2):1.
Papoutsis G, Papoutsi S, Klukowska-Rötzler J, Schaller B, Exadaktylos AK. Temporomandibular joint dislocation: a retrospective study from a Swiss urban emergency department. Open Access Emerg Med OAEM. 2018;10:171.
Oliphant R, Key B, Dawson C, Chung D. Bilateral temporomandibular joint dislocation following pulmonary function testing: a case report and review of closed reduction techniques. Emerg Med J. 2008 Jul;25(7):435–6.
Chen Y-C, Chen C-T, Lin C-H, Chen Y-R. A safe and effective way for reduction of temporomandibular joint dislocation. Ann Plast Surg. 2007 Jan;58(1):105–8.
Gorchynski J, Karabidian E, Sanchez M. The “syringe” technique: a hands-free approach for the reduction of acute nontraumatic temporomandibular dislocations in the emergency department. J Emerg Med. 2014;47(6):676–81.
STEPHEN GILMARTIN
Emergency Registrar
Stephen is an emergency medicine doctor from Ireland. He has interests in trauma, ultrasound and medical education. He’s amazed that your brain is active 24/7, 365 days of the year until your death, the only two times it stops is during an exam and when you’re trying to write a funny bio!
