Save your Thumbs: Extra-oral reduction of anterior mandibular dislocations
Resident Clinical Pearl (RCP) – February 2017
Kavish Chandra, PGY2 iFMEM, Dalhousie University, Saint John, New Brunswick
@kavishpchandra
Reviewed by Dr. Paul Frankish and Dr. David Lewis
Mandibular dislocations can be atraumatic or traumatic. The atraumatic variety can occur after extreme mouth opening from yawning, laughing or vomiting and can cause severe pain, difficulty swallowing and malocclusion of the jaw (1).Anterior mandibular dislocations are the most common form of atraumatic dislocations and can be bilateral or unilateral. In this injury, the temporal mandibular joint (TMJ) dislocates in front of the articular eminence and muscular spasm traps the mandible in that position (2).(Fig. 1A and B)
Figure 1A: TMJ and coronoid (black arrow) in normal resting position. Figure 1B: TMJ dislocates anteriorly and the coronoid (black arrow) is palpable just below the zygoma. Adapted from Chen et al. 2007.
Various reduction techniques are described and predominantly involve intra-oral manipulation, often with the use of procedural sedation (Fig. 2) (1). With the intra-oral technique, there is a risk of the mandible snapping shut on the operator’s fingers as well as the risk of a failed reduction and risks of procedural sedation.
Figure 2: Intra-oral TMJ reduction with thumb on molars and pressure is applied downwards and backwards. Adapted from Tintinalli’s Emergency Medicine.
The Question: is there an effective extra-oral reduction technique for anterior mandibular dislocations?
Chen et al. (2007) published a case series describing a rapid and effective extra-oral reduction method for anterior mandibular dislocations(2). Furthermore, their technique does not require any procedural sedation and analgesia, thereby minimizing risks to the patient and freeing up valuable ED resources.
Figure 3: With your fingers, pull the mandible forward (large arrow) while using the ipsilateral zygoma as fulcrum (little arrow). This further dislocates the TMJ anteriorly and facilitates contralateral TMJ reduction. See Figure 4 to perform the concurrent contralateral TMJ reduction. Adapted from Chen et al. 2007.
Figure 4: On the opposite side, place your thumb just above the palpable coronoid process and apply persistent pressure to push the coronoid and TMJ back (big and little arrow). Figure 3 and 4 are reversed to facilitate TMJ reduction on contralateral side. Adapted from Chen et al. 2007.
Why not watch this technique in action:
References
- Tintinalli, JE. (2016). Eye, ear, nose, throat and oral disorders. (8th ed.) Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (pages 1590-1591). New York: McGraw-Hill.
- Chen Y, Chen C, Lin C, Chen Y. A safe and effective way for reduction of temporomandibular joint dislocation. Ann Plast Surg. 2007;58(1):105-108. [PubMed]
- https://www.aliem.com/2016/trick-of-the-trade-extra-oral-technique-for-reduction-of-anterior-mandible-dislocation/
