Authors of section

Author

Boaz Arzi

Executive Editor

Amy Kapatkin

General Editor

Frank Verstraete

Open all credits

External skeletal fixator

1. Principles

Restoration of occlusion and normal anatomy is crucial to avoid long term complications such as malocclusion, malunion, nonunion, refracture, facial asymmetry and loss of function.

2. Approach

Pharyngeal intubation is needed to assess and maintain occlusion throughout and following the surgery.

Pharyngeal intubation in a dog

With the patient in dorsal recumbency, a ventral approach to the mandibular body or bodies is performed. The incision should expose enough intact bone to place at least two K-wires on both sides of the fracture.

Alternatively, a minimally invasive approach can be used.

Note: External skeletal fixation of the mandible can be done in a closed fashion, with percutaneous pin placement, as long as reduction can be achieved.

Ventral approach in a dog mandible with body unilateral comminuted fracture

3. Reduction

The mandible and maxilla should be closed in the desired occlusion. This will align the bones into normal occlusion

The technique uses 26 or 28 gauge wire. The wires are looped around all four canine teeth and twisted together to lock the mouth in normal occlusion.

The mandible and maxilla should be closed in the desired occlusion in a dog with body unilateral comminuted fracture

4. Fixation

General considerations for K-wires insertion

The external skeletal fixator is applied to span the fracture site and K-wire placement must avoid the mandibular tooth roots.

At least two percutaneous smooth K-wires should be placed on either side of the fracture margin.

External skeletal fixator in a dog with mandible body unilateral comminuted fracture

Incisions

Either a surgical incision or small percutaneous incisions are performed to insert the K-wires.

K-wire insertion

The K-wires are placed at a 15°-20° angle to enhance purchase of the K-wires in the bone. Smooth K-wires are used to avoid trauma to the neurovascular bundle in the mandibular canal if the K-wires penetrate the canal.

The rostral K-wire closest to the fracture site should be inserted first alternating until all the K-wires are inserted.

External skeletal fixator in a dog with mandible body unilateral comminuted fracture K-wire insertion order

K-wires will engage one mandible and not cross over the intermandibular space reaching the other mandible. This is true in application of bilaterally placed external skeletal fixator.

External skeletal fixator in a dog with mandible body unilateral comminuted fracture K-wire insertion

Application of tube and dental acrylic

A silicon tube is placed over the K-wires with at least 2-3 K-wires present on each side of the fracture.

The tube should only be penetrated on one side to avoid the escape of the material.

External skeletal fixator with tube in a dog with mandible body unilateral comminuted fracture

Dental acrylic or custom tray material is mixed to prescribed consistency and placed into a catheter tip syringe.

It is injected into the tube in the liquid phase.

External skeletal fixator with tube and dental acrylic insertion in a dog with mandible body unilateral comminuted fracture

Dental acrylic or custom tray material is allowed to solidify.

External skeletal fixator with tube and dental acrylic in a dog with mandible body unilateral comminuted fracture

5. Aftercare

The patient should wear an Elizabethan collar until removal of the construct.

Multimodal analgesia is recommended. Non-steroidal medication for 10-14 days and opioids for the first 5 days post-surgery as needed.

Antibiotic therapy is prescribed for a period of 10-14 days following surgery.

The exposed pins are cleaned at least once daily using 0.12% chlorhexidine gluconate solution. Another option is to use a water-flossing device.

A radiographic recheck is performed every 6 weeks until the fracture is healed.

The external skeletal fixator is removed when the fracture is healed.