The method of approach to the fracture would depend on which one would be least traumatic, but effective to approach the fractured bone taking into account the topographic anatomy. In addition, blood supply and other structures such as nerves and salivary duct need to be avoided.
Both intraoral approach and extraoral 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.
The intraoral approach may be used for fractures of the caudal maxilla if it provides better visualization and access.
3. Irrigation of the fracture
Irrigation of the fractured area is required to eliminate debris and possible foreign material.
When a fracture is depressed or displaced, 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 nasal cavity or devitalized, it should be removed to avoid the formation of a sequestrum.
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 caudal maxillary 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.
The plates are applied spanning the fracture margins. Loose vital bone fragments can be incorporated into the fixation.
Note: Care should be taken to avoid placing screws into the infraorbital canal or the root structures.
The length of the screws can be determined by using CT measurements of the bone thickness and a depth gauge.
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.
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.
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.
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.
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.
Typically, titanium miniplates and screws are osseointegrated. If there is no implant failure or infection, there is no need for implant removal.