Authors of section

Author

Boaz Arzi

Executive Editor

Amy Kapatkin

General Editor

Frank Verstraete

Open all credits

Plate fixation

1. Principles

The overall goal is to restore normal anatomical contour and allow for normal function.

Restoring and maintaining occlusion is the most important aspect of panfacial fixation.

Pharyngeal intubation is required to assess and verify occlusion, during and after the surgery. If the panfacial fractures do not affect the occlusion, pharyngeal intubation in not necessary.

general considerations with midface fractures

From a biomechanical standpoint, the maxillofacial structures are relatively lightweight. Yet they have strong frames made of thin bones that also form the nasal cavity and paranasal sinuses. These maxillofacial frames are strengthened by the buttresses, which are thicker areas of the bones, designed to distribute the forces of mastication. The buttresses also help to maintain the position of the maxilla in the appropriate relationship with the base of the skull and the mandible. There are lateral, medial and caudal buttresses. The objective of reconstructing midfacial fractures is to restore these buttresses as well as the orbit and frontonasal vault. Fixation of bone fragments is done from the most unstable to more stable, in order to ‘simplify’ the fracture.

general considerations with midface fractures

2. Preparation and approach

For this procedure, one of the following patient positions is used:

Both intraoral approach and extraoral dorsal midline approach can be used. Use the least traumatic approach that allows effective fracture reduction and fixation. Avoid blood vessels, nerves and the salivary duct.

The extraoral approach usually has the best access for open reduction and plating.

dorsal midline approach

The intraoral approach may be used for fractures of the caudal maxilla if it provides better visualization and access.

intraoral approach to the maxilla

3. Irrigation of the fracture

The fracture must be irrigated to eliminate debris and possible foreign material. The brain may be exposed with a frontal sinus fracture. Therefore irrigation should be performed away from the brain.

plate fixation

4. Reduction

When a fracture is depressed, one or two periosteal elevators are placed underneath the fragment and the whole fracture complex is elevated to restore the normal anatomical contour.

Note: Care should be taken to avoid vascular damage during the reduction as the bone edges may be very sharp.

If a bone fragment is dislodged into the frontal sinus or devitalized, it should be removed to avoid the formation of a sequestrum.

plate fixation

5. Fixation

Plate selection and preparation

One or more low-profile titanium 2mm non-locking miniplates are contoured using specially designed miniplate bending pliers, and adapted to the desired anatomical site. This allows for accurate repositioning and reconstruction of the frontonasal area. The length of the plate should allow for at least two screws on each side of the fracture. Three screws per fracture fragment (six cortices) are ideal.

plate fixation

Plate application

The plates are applied spanning the fracture margins. An adequate number of plates should be applied to provide stability to the fractured segment.

plate fixation

Note: Specifically for caudal fractures, care should be taken to avoid placing screws into the infraorbital canal or the root structures.

Note: Management of fractures involving the orbit should avoid damaging the eye globe.

Note: Management of fractures involving the palate should attempt to preserve the integrity of the major palatine artery.

The length of the screws can be determined by using CT measurements of the bone thickness and a depth gauge.

plate fixation

As a general guide, the sequence of plate placement is initiated from reconstruction and fixation of the facial region buttresses to serve as a base for other fragments to be secured.

Alternatively, comminuted displaced fractures can be 'simplified' by stabilizing the largest fragments first. Once the large fragments are secured, the smaller fragments are stabilized and fixed.

The plates are secured to the bone with at least two non-locking, self-tapping titanium screws in each segment of the fracture.

From a biomechanical standpoint, the maxillofacial structures are relatively lightweight. Yet they have strong frames made of thin bones that also form the nasal cavity and paranasal sinuses. These maxillofacial frames are strengthened by the buttresses, which are thicker areas of the bones, designed to distribute the forces of mastication. The buttresses also help to maintain the position of the maxilla in the appropriate relationship with the base of the skull and the mandible. There are lateral, medial and caudal buttresses. The objective of reconstructing midfacial fractures is to restore these buttresses as well as the orbit and frontonasal vault. Fixation of bone fragments is done from the most unstable to more stable, in order to ’simplify’ the fracture.

midface panfacial nondisplaced

6. Closure

The soft tissues are closed routinely in two layers. A Stent bandage is secured in place for 72 hours in order to minimize postoperative swelling and emphysema.

plate fixation

7. Case example

A 2-year-old Coonhound with a displaced and depressed panfacial fracture from being kicked by a horse.

plate fixation

Preoperative 3D CT images.

definition

The dorsal midline approach was used to expose and reduce the fractures.

plate fixation

The fracture was repaired using multiple 2.0mm non-locking titanium miniplates.

plate fixation

Nasal cavity, preoperative (a) and postoperative (b) CT images.

plate fixation

Orbit, preoperative (a) and postoperative (b) CT images.

plate fixation

Postoperative 3D CT images.

plate fixation

Postoperative CT image (left) at 18 months showing completely healed and remodeled bone.

The right rhinoscopic image shows a screw tip in the nasal cavity with fungal plaques covering it. Aspergillus fungal infection was diagnosed making it necessary to remove all implants.

Additional treatment to resolve the Aspergillus fungal infection was done.

plate fixation

8. Aftercare

The dog should be kept on soft food for one or two weeks after surgery.

Intraoperative intravenous administration and then oral antibiotics for one to two weeks is recommended. Antibiotics used should have an excellent oral cavity penetration and spectrum. Example: ampicillin at 20 mg/kg intravenous antibiotics followed by oral antibiotics amoxicillin/clavulanic acid at 15-20 mg/kg orally twice daily.

Pain medication, such as opioids and non-steroidal anti-inflammatory medications, are used for 7-14 days.

If the fracture involved the oral cavity, oral rinse with 0.05-0.12% chlorhexidine gluconate solution is recommended (not for maxillomandibular fixation).

Recheck is recommended in 10-14 days and at three and six months post-surgery.

If there are any signs of complications (i.e. purulent nasal discharge), CT and rhinoscopy are indicated.

Implant removal

Typically, titanium miniplates and screws are osseointegrated. If there is no implant failure or infection, there is no need for implant removal.