It’s 0300 and you are on a solo night shift when a couple are rushed into the resuscitation bay by the triage nurse. The woman says that the man had his jaw “wired shut” three weeks ago and began retching an hour ago. Your suspicions are confirmed when you look at his mouth and see the image below:

Figure 1. Arch bars (green arrows) are used for mandibular fixation, adapted from Jones and Read (2006).

As your patient is being placed on cardiac and oxygen monitoring, you can see they are agitated and hypoxic. You ask yourself, how can I get access to their oropharynx and begin my resuscitation?

Background

Arch bars and intermaxillary fixation are placed after mandibular fractures. In Figure 1, the arch bars, horizontal bars indicated by the green arrow, are fixated by circumferential wires around the teeth.¹ In order to fixate the mandible and maxilla, fixation wires (vertical wires indicated by the red arrow seen in Figure 2) bring together and upper and lower arch bars, effectively eliminating mouth opening.¹

Figure 2. Intermaxillary fixation wires, vertical wires indicated by the red arrows. Adapted from Jones and Read (2006).

While it is standard procedure for dentists and oral surgeons to provide patients with wire cutters and instructions following intermaxillary fixation for emergencies, this may not be readily available in the emergency department when needed the most.

The materials required:

1. A deep breath
2. Wire cutters (or if not, heavy metal scissors)
3. Hemostat or needle driver

The steps:

1. Identify and cut the vertical fixation wire on one side of the twist as seen in Figure 2. This is similar to cutting a single interrupted suture.
2. Pull on the twist with a hemostat or needle driver and pull the wire out. There are generally 2-4 fixation wires per each side that require cutting in order to open the mouth.
3. In some instances, there may be heavy elastics vertically as well, pull and cut those as well.
4. Proceed with the resuscitation as deemed necessary (airway access or allowing the patient to vomit)
5. The dentist or oral surgeon can re-fixate the wires non-urgently after the emergency has passed

See the following links on how arch bars and intermaxillary fixating wires are placed (to get an understanding of where to cut to release the mandible)

1. https://www.youtube.com/watch?v=RGp46yHoVag&feature=youtu.be (minute 14 and on for application of intermaxillary fixation wires)
2. https://emcrit.org/racc/airway-decisions/

Pearl: consider having wire cutters as part of your difficult airway cart or kit

Bottom Line: intermaxillary fixation can pose a serious threat to a patient needing to vomit or one that requires emergency airway access. Be prepared to cut the right wires in order allow mouth opening.

References

This post was copyedited by Kavish Chandra @kavishpchandra