Non-Invasive Techniques for Maxillofacial Fracture Repair
Lo�c Legendre Canada
Facial fractures result from severe trauma, be it serious falls or automobile accidents, and the affected animal usually presents in a state of shock that requires immediate attention. A detailed examination followed by a radiographic survey is necessary to evaluate the extent of the damage. Repair is next; the goal here is to allow the patient to resume normal feeding as soon as possible. This last step is where most of the complications occur. This article will cover the various problems that one encounters when dealing with these cases.
In many cases, emergency care and shock treatment are priorities. Further examination has to wait until the patient is stable enough to be sedated or anesthetized. Gentle palpation and manipulation of the jaws are required to verify whether they are in occlusion. Radiographs of the suspected fracture sites are also mandatory. Survey films are very important because it is so easy to miss non-displaced fractures that are fairly common when dealing with the skull. There is a definite advantage in owning and using a dental x-ray machine here. Dental radiographs provide the operator with intraoral views that eliminate superimposition of bony structures and therefore greatly facilitate the diagnosis of skull fractures.
Mandibular fractures are obvious and it is easy to concentrate on mandibular damage and miss maxillary trauma. Epistaxis is often the result of turbinates or nasal septum fractures. Its presence dictates that a maxillary radiograph be obtained.
The animal usually presents soon after the accident. The immediate considerations are airway obstruction, hemorrhage, shock, lung contusion, open fractures, and pain management. Following the initial examination, treatment consists of fluid therapy, anti-shock corticosteroids (methylprednisolone or dexamethazone), fracture stabilization using Robert-Jones bandages or splints, chest radiographs, and pain medication. If there are open fractures or wounds, an antibiotic regimen is instituted. In cases of severe blood loss, a PCV is done and replacement therapy is started as necessary. During the exam, one should note mobility and possible displacement of the mandible. One should also check whether or not the patient can close its mouth and whether or not there was epistaxis. The patient�s ability to close its mouth sufficiently to swallow needs to be restored.(1)
This is the most challenging but also the most interesting aspect of the case. The treatment goals are: realignment to normal occlusion, minimal invasiveness, minimal morbidity, early return to self-feeding, and pain control.(1-3) When dealing with facial fractures, the repair has to be stable but not necessarily rigid. Remember, the body of the mandible is not a weight-bearing bone. The use of intramedullary pins, plates, and screws is cautioned against as it can easily result in radicular (tooth root) damage. Pins, plates, and screws have further disadvantages: they are expensive and require specialized equipment and training. The upper jaw and the nasal cavity consist of thin bone plates that is almost impossible to fix rigidly.(2) Wires are preferred because they are easier, less expensive, and have less harmful side effects. Acrylic intraoral splints remain the method of choice, as they are easy, fast, and non-invasive.(4) The patient is anesthetized and intubated. If it has not already been done, a radiological survey of both mandible and maxilla is completed.
If the mandibular symphysis is separated, wire it together. A wire loop entering under the chin and passing distal to the canines combined with a figure eight wire looped around the base of the canines yield excellent results.(4)
Fractures of the Body of the Mandible
Fractures of the body of the mandible are rare (1) but need to be stabilized. Commonly, with a favorable fracture (1, 3), one wire loop going through holes placed at least 5mm on either side of the fracture is usually sufficient. One is addressing the osseous defect directly. Another way to fix this type of fracture is to use an intraoral acrylic splint. This technique does not address the bone defect directly but rather uses the teeth as anchors to realign the bone. In other words, your main goal is to keep the teeth in occlusion and the bone will heal in the correct position. Fixing a jaw fracture is no longer an orthopedic problem but a dental one. The teeth to be incorporated into the splint are cleaned and polished using a non-fluoridated pumice. The teeth are then aligned into an anatomic position, etched, rinsed, and dried. The composite resin is added to the teeth and allowed to cure. When dealing with a mandibular fracture, most of the resin needs to be added to the lingual surface of the teeth not to interfere with the occlusion. Once cured the splint is checked for any sharp edge or overhang. These need to be removed using a Goldie or a laboratory bur. One ends up with a ribbon of acrylic bonded to the lingual surface of the mandibular teeth. The splint is intraoral and unobtrusive. The jaw is supported and functional. The patient can start eating soft food right away. The standard technique when repairing an unfavorable fracture (1) is to pass two loops of wire through three or four holes.(3) Acrylic splints can also be used in the same manner as above, but it is wise to reinforce them with one or two circlage wires around the mandible.
These are commonly stable and non-displaced, and they rarely require individual stabilization. Exceptions would be when the fractures result in malocclusion, facial deformity, oronasal communication, instability, or obstruction of the nasal passages.(2) In those cases, one can try to align fragments of maxilla and hold them in place using wires and/or titanium plates with micro screws, or one can align the maxillary teeth and hold them by running an intraoral splint on the buccal surface of the maxillary teeth. Another technique consists in bonding the upper canine teeth to the lower canine teeth. If the mandibular teeth are in the normal position and the maxillary canine teeth are bonded to them in the correct relationship, then the maxilla is going to heal in the anatomic position. If the canine teeth overlap by 2 mm, the mouth is open wide enough to allow the patient to lap semi-liquid food.
Maxillary and Mandibular Fractures
These cases are more often encountered in cats than in dogs. Pushing the above principal one step further, one reconstructs the mandible first, using acrylic splint and wire, and then aligns the maxilla to the repaired mandible. Once again, the goal is to be able to close the mouth in occlusion. Rather than try to fix multiple maxillary fractures, the teeth are used as markers and anchors. Once they are correctly lined up, the canines are bonded together. Both jaws are immobile but the patient can still lap food and thrive.
The Edentulous Patient
So now you are using the teeth as fixation points to repair jaw fractures, but what do you do when faced with an edentulous patient. The usual presentation is a geriatric toy breed suffering from chronic advanced periodontal disease referred to you because of a spontaneous or iatrogenic fracture of the mandible at the level of the first molar. The responsible tooth, if still present, has to be removed because the whole area is infected. You are left with a lot of granulation tissue and little, if any, bone. Even if you wanted to, you could not use screws, plates, pins, or wires. First, debride and clean the area, and close the soft tissue defect. Enter a wire from the ventral edge of the mandible dorsally on the buccal surface of the mandible, loop it in the mouth, and push it back ventrally on the lingual surface of the mandible so that it exits through the entrance hole. Do this on both mesial and distal fragments of the mandible. Make sure the alignment of the mandible is correct. Apply a ribbon of acrylic over the length of the body of the mandible, incorporating both wire loops. Build up the acrylic until it is 7 to 10 mm diameter. Before the acrylic is set, pull on the wire ends, under the jaw, to tighten the loops into the acrylic. Add some acrylic to cover the wires in the mouth. Smooth out the tube of acrylic. Once dry, you have a rigid conforming splint, fixed to both fragments of the mandible. The apparatus is intraoral, except for two small twisted wire ends under the chin. The patient can eat soft food right away. The splint needs to be kept clean daily and is removed five to eight weeks later.
We are dealing with bony fractures but sometimes teeth are in the way. Teeth in the line of fracture do not necessarily need to be extracted. Extraction is recommended if the tooth is endodontically or periodontically involved and is not aiding in the stabilization of the fracture. A healthy tooth in the line of fracture can be retained as long as further treatment is planned.(3) Endodontic treatment will be needed within six months.
In the text above, the author used the term acrylic in a general way to cover both acrylic and composite resins. Acrylics are cost-effective but time-consuming, as powder and liquid have to be mixed in-situ. Light-cured composite resins are also time-consuming, as they have to be cured in increments. New, chemical-cured, self-mixing resins considerably speed up the procedure but also add cost to the client. Pain control is easily achieved by placing a fentanyl dermal patch on the chest, five to eight hours prior to the surgery.(5) If the patch is placed at the time of the surgery, an injectable analgesic will be necessary until the patch becomes active.
The patient is usually sent home the following day on a semi-liquid diet and with recommendations to be kept indoors, and to come back in five days for a recheck visit and to remove the patch. A chlorhexidine solution is sent home to be used twice daily to clean the mouth and the splint. These patients do slobber at first and it is recommended that their faces and front paws be washed daily. If any open wounds were present, appropriate antibiotics are prescribed for seven to 10 days.
The next visit is set for five to eight weeks after the operation.(4,6) The patient is anesthetized, intraoral radiographs are obtained, and if they show good healing, the splint is removed and the teeth are polished clean. A shorter time interval does not permit complete bone healing, but once again, with facial fractures, bone rigidity is not essential as long as there is good stability. The patient stays on soft food for another two weeks before returning to the diet of its choice.
The goal of mandibular and maxillary fracture repair is to stabilize the fragments and to regain normal occlusion. Invasive techniques such as pins, plates and wires can cause radicular as well as more soft tissue damage.(3) Standard orthopedic techniques often provide compression that combined with rigid fixation, facilitate rapid bone healing. In the case of facial trauma, the same techniques often exacerbate the compression of fragments and aggravate malocclusion.(4) In these cases, anatomic occlusion and functionality are more important than rigidity of the fixation. Intraoral acrylic splints help achieve these points. They are quick, they minimize tissue exposure and morbidity, and they allow early return to normal feeding.
Their use is most beneficial when dealing with multiple fractures. The teeth are used as anchors and when they are manipulated in occlusion, they bring the bone fragments back into alignment. The acrylic splints hold everything into place. They are the technique of choice as they are quick, easy, and non-invasive and provide excellent results. Think as dentists! Use the teeth!
1. Harvey CE, Emily P. Small Animal Dentistry. Philadelphia: Mosby-Year Book, Inc., 1993: 312-335.
2. Gorrel C, Penman S, Emily P. Small Animal Oral Emergencies. New York: Pergamon Press, 1993: 37-45.
3. Wiggs RB, Lobprise HB. Veterinary Dentistry Principles and Practice. Philadelphia: Lippincott�Raven Publishers, 1997: 259-279.
4. Legendre LFJ. Use of maxillary and mandibular splints for restoration of normal occlusion following jaw trauma in a cat: a case report. J Vet Dent 1998; Vol. 15 no.4 (Dec): 179-181.
5. Scherk-Nixon M. A study of the use of a transdermal fentanyl patch in cats. JAAHA 1996; 32: 19-24.
6. Colmery III B. Maxillofacial surgery. Proc Sixth World Vet Dent Congress 1999.
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