Mandibulomaxillary fixation (MMF)

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 Principles: general considerations
 Arch bars: indications
 Arch bars: general considerations
 Arch bars: preparation
 Arch bar: bar position
 Arch bars: bar fixation
 Arch bars: mandibulomaxillary fixation (MMF)
 Other methods: Ernst ligatures
 Other methods: bone supported devices
Principles: general considerations

Rigid fixation techniques in the dentate patient begin with fixation of the occlusion. This ensures that the patients maintain their preoperative occlusal status. There are several techniques to providing mandibulomaxillary fixation (MMF). Many surgeons agree that the gold standard in MMF is the use of arch bars. However, there are various methods of MMF to be used in specific clinical situations.

Common MMF methods are:

  • Arch bars (described in this document)
  • Ernst ligatures (click here for a detailed description)
  • Bone supported devices including intermaxillary fixation (IMF) screws, hanger plates and interarch miniplates (click here to learn more about bone supported devices)

There other methods of wire fixation such as Ivy loops, Gilmer wiring, Stout wiring and Kazanjian buttons to name but a few.


AO Teaching video on mandibulomaxillary fixation (MMF)


Arch bars: indications

Arch bars are preferred:

  • For temporary fragment stabilization in emergency cases before definitive treatment
  • As a tension band in combination with rigid internal fixation
  • For long-term fixation in conservative treatment
  • For fixation of avulsed teeth and alveolar crest fractures

Arch bars: general considerations

There are important points to consider before starting.
The occlusion must be checked. In the case of jaw malformations, such as a deep bite deformity, it may be impossible to use arch bars.
There should be calculable tension forces on both bars, so the hooks should be symmetrically positioned in the upper and lower jaw. This symmetry is essential for functional training with elastics.

One pitfall when using arch bars is the risk of contamination of bloodborne infection from patients. Passing the wires to secure the arch bar can result in a puncture or tear in the surgeon’s glove and the possibility of disease transmission to the surgeon.


Arch bars: preparation
Mandibulomaxillary fixation (MMF)

Check occlusion
Before inserting the arch bars, check the occlusion. There should be full interdigitation of the teeth with regular contacts.

Determine if the patient has a normal occlusion or a preexisting malocclusion before taking the patient to the operating room.


Mandibulomaxillary fixation (MMF)

Adjusting the shape
The prefabricated arch bar must be adjusted in shape and length according to the individual situation. The arch bar should not damage the gingiva.

Firstly, the bar is adapted closely to the dental arch. The bar should be placed between the dental equator and the gingiva.


Mandibulomaxillary fixation (MMF)

Trimming the bar
The bar should be trimmed to allow ligation to as many teeth as possible. The bar should not extend past the most distal tooth or protrude into the gingiva as this will be an irritation to the patient.


Arch bar: bar position
Mandibulomaxillary fixation (MMF)

Symmetric bar position
To achieve calculable tension forces on both bars, the hooks must be positioned symmetrically in the upper and lower jaw. This symmetry is essential for functional training with elastics.


Arch bars: bar fixation
Mandibulomaxillary fixation (MMF)

Ligature preparation
To fix the arch bar in place, prepare a ligature in the premolar region of each side. The wire ends should not damage the surrounding soft tissues.


Mandibulomaxillary fixation (MMF)

Attaching the bar
Position the arch bar and fix it using the wire twister.

In the premolar and molar regions one end of the wire is above the arch bar and the other end below it.


Mandibulomaxillary fixation (MMF)

Wire end
Cut the wire with the cutter and turn the ends away from the gingiva to prevent damage.


Mandibulomaxillary fixation (MMF)

Make sure the wire rosettes do not protrude away from the arch bar as this will be an irritation to the patient.


Mandibulomaxillary fixation (MMF)

Photographs show arch bars applied to mandible and maxilla.


Mandibulomaxillary fixation (MMF)

Arch bars: mandibulomaxillary fixation (MMF)

General considerations
Mandibulomaxillary fixation (MMF) can be used either intraoperatively to establish the correct occlusion or as part of postoperative management of the patient’s injury. MMF may be accomplished with wires or training elastics depending on the overall treatment plan for this patient.


Mandibulomaxillary fixation (MMF)

With wires
The wire loop is placed over the maxillary and mandibular lugs of the arch bar and the wire loop is tightened.


Mandibulomaxillary fixation (MMF)

MMF completed with wire fixation. At least three wires, a posterior wire loop in each side, and an anterior wire loop will provide stable fixation.


Mandibulomaxillary fixation (MMF)

Elastics
Some surgeons prefer MMF with elastics for intraoperative management of the occlusion. Additionally, postoperative training elastics can be used to manage condylar fractures in a closed manner.


Other methods: Ernst ligatures
Mandibulomaxillary fixation (MMF)

Click here for a description of Ernst ligature application.


Other methods: bone supported devices
Mandibulomaxillary fixation (MMF)

Click here for a detailed description of bone supported devices and their application.