Authors of section

Author

Boaz Arzi

Executive Editor

Amy Kapatkin

General Editor

Frank Verstraete

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Intraosseous wiring

1. Principles

The overall goal is to restore occlusion, normal anatomy and function. Restoring and maintaining occlusion is the most important aspect of fixation of the mandibular fractures.

Intraosseous wire fixation in a dog mandible with body unilateral simple fracture

Simple, unilateral mid body mandibular fractures can be repaired with 2 intraosseous wires. This method should be used on stable fractures that interdigitate.

Intraosseous wire fixation is not recommended for comminuted or bilateral mandibular fractures.

Example of intraosseous wire fixation in a dog mandible with body unilateral simple fracture

2. Positioning and approach

This procedure is performed through the ventral approach to the mandibular body, with the patient placed in dorsal recumbency.

dorsal recumbency   midface

3. Preliminary assessment

The fractured area is clipped to assess for penetrating injuries. If a penetrating wound is found, an exploratory surgery and debridement of the area is indicated to remove any foreign bodies (i.e. hair).

A comprehensive intraoral examination must be performed to assess for any injury affecting occlusion, teeth trauma and periodontal tissues.

Dental radiographs and a CT are obtained to provide details about the dentoalveolar structures in relationship to the fractures.

4. Reduction

Reduction of the fracture is done digitally, bringing the teeth into normal occlusion, which realigns the bones.

The image shows malocclusion assessed by palpation.

Malocclusion assessed by palpation in a dog mandible with body unilateral simple fracture

Small loose bone fragments devoid of soft tissue attachments should be removed.

Teeth that are periodontally stable but are fractured near the fracture line should be left in place. They should be temporarily treated endodontically by a partial coronal pulpectomy to provide pain relieve and avoid infection at the fracture site.

Root canal treatment or tooth extraction is performed when the fracture is healed.

5. Fixation

Placement of drill holes

Drill holes are planned to avoid tooth roots and the mandibular canal. 2 wires should be used to provide adequate stabilization. The wires should be placed at a 20° angle to each other or in a triangle configuration.

Placement of drill holes for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

The drill holes should be 0.5-1.0 cm away from the fracture line and drilled with a 10° angulation towards the fracture line to facilitate the passage of the wire.

Placement of drill holes for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

A smooth K-wire is used for drilling when close to the mandibular canal. This decreases the risk of damage of the neurovascular bundle. A drill bit can be used when the mandibular canal can be avoided.

Holes drilling for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

Wire insertion and tightening

Size of the orthopedic wire depends on the size of the mandible. Size 22-24 is adequate for toy breed dogs and cats; 18-20 gauge is adequate for large breed dogs.

The wire is pre-stretched before insertion.

Wire pre-stretching for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

The wires are passed through the pre-drilled holes and twisted so the knot is on the buccal surface.

Wire insertion for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

Maintain tension while twisting the wire and bend during the final twisting.

Wire tightening for intraosseous wire fixation in a dog mandible with body unilateral simple fracture

Occlusion evaluation

Recheck occlusion after wire fixation because the bone fragments may have shifted.

Closure

The wire is cut leaving 3-4 twists.

Wire cut in intraosseous wire fixation in a dog mandible with body unilateral simple fracture

Avoid shifting the fracture fragments when bending the wire. It may affect the bone alignment, but is necessary to avoid soft tissue damage and pain.

Example of intraosseous wire fixation in a dog mandible with body unilateral simple fracture

6. Debridement and suturing

If wounds are present, they should be debrided followed by copious irrigation with sterile saline 0.9%. Soft tissue lacerations are sutured in 2 layers using 4.0 poliglecaprone 25 or other monofilament absorbable suture in a simple-interrupted fashion.

Note: in the oral cavity, due to abundant blood supply, aggressive debridement is rarely needed.

The skin incision is closed with 4-0 monofilament nonabsorbable in a simple interrupted fashion.

7. Aftercare

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

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

The wires are kept in place until the fracture is healed (usually 6-8 weeks) and removed under general anesthesia using ventral approach.