A minimum of two points of fixation should be used to provide stable internal fixation of mandibular symphysis fractures:
A- Apply the first plate to the inferior border of the mandible.***
Use a 1.5 mm drill bit with 6 mm stop to drill monocortically through the plate hole next to the fracture.
B- Apply the first plate to the inferior border of the mandible.
Use a 1.5 mm drill bit with 6 mm stop to drill biocortically through the plate hole next to the fracture.
Insert a 2.0 mm screw, 6 mm in length a 2.0 mm screw, 6 mm in length.
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In healthy cats and dogs, great force (trauma) is necessary to fracture the jaw (lower jaw). A fracture is a broken bone and can vary in severity, from a fissure (incomplete fracture) to a severe comminuted fracture (many pieces). Vehicular trauma is the most frequent cause of mandibular fractures. Due to the intensity of trauma associated with mandibular (maxillary) maxillary (upper jaw) or skull fractures, it is possible that the lesions are not only in the face area and pets often need treatment of other lesions before the fracture is definitively treated. The primary care veterinarian may recommend X-rays of other parts of the body before focusing on the jaw. Thoracic (chest) injuries often occur at the same time and may manifest as pulmonary contusions (lung hematomas), pneumothorax (perforated lung), diaphragmatic hernia and traumatic myocarditis (heart hematoma that causes arrhythmias). It is very important to evaluate the entire body first, since these other injuries could be life-threatening.
Sometimes, there is no history of trauma. In these cases, a pathological fracture (fracture caused by a disease) should be considered. Diseases such as severe bone deterioration of a tooth / jaw and cancer can weaken the bone and make it easier for you to suffer a fracture. Pathological fractures usually affect older animals more often than young animals.
The jaw and upper jaw have unique characteristics compared to the rest of the skeleton that complicate the treatment of fractures. The jaw is composed of two bones joined in the midline by a symphysis (non-mobile joint). The roots of the teeth, nerves, blood vessels and salivary ducts are all inside the jaw and next to it. These structures usually suffer trauma with a mandibular fracture.
Clinical manifestations:
Symptoms of mandibular fractures include:
- refusal to eat
- bleeding from the mouth
- bad jaw alignment
- wounds around the mouth, pain and swelling in the area, mouth that remains open
- excess salivation that may be stained with blood.
Diagnosis:
Due to the inconvenience of this injury, the veterinarian may recommend sedation or anesthesia for the pet before palpating the injured area and doing more tests. Due to the minimum amount of soft tissues that cover the jaw, it is common for these fractures to be open. An open fracture is a fracture in which the protective layer of soft tissues around the bone opens, showing the edges of the broken bones outward.
Once the veterinarian determines that the pet is stable enough to focus on the tests and treatment of the mandibular lesion, x-rays of the jaw will be recommended to confirm if there is a fracture and guide treatment recommendations. Due to the complex anatomy of the jaw, teeth and skull, radiographs are usually performed under severe sedation or general anesthesia. This will reduce the stress of the pet and allow optimal placement to interpret the complicated images. In some cases, a CT scan may be recommended to obtain more information about the complex anatomy and determine the best surgical plan.
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In healthy cats and dogs, great force (trauma) is necessary to fracture the jaw (lower jaw). A fracture is a broken bone and can vary in severity, from a fissure (incomplete fracture) to a severe comminuted fracture (many pieces). Vehicular trauma is the most frequent cause of mandibular fractures. Due to the intensity of trauma associated with mandibular (maxillary) maxillary (upper jaw) or skull fractures, it is possible that the lesions are not only in the face area and pets often need treatment of other lesions before the fracture is definitively treated. The primary care veterinarian may recommend X-rays of other parts of the body before focusing on the jaw. Thoracic (chest) injuries often occur at the same time and may manifest as pulmonary contusions (lung hematomas), pneumothorax (perforated lung), diaphragmatic hernia and traumatic myocarditis (heart hematoma that causes arrhythmias). It is very important to evaluate the entire body first, since these other injuries could be life-threatening.
Sometimes, there is no history of trauma. In these cases, a pathological fracture (fracture caused by a disease) should be considered. Diseases such as severe bone deterioration of a tooth / jaw and cancer can weaken the bone and make it easier for you to suffer a fracture. Pathological fractures usually affect older animals more often than young animals.
The jaw and upper jaw have unique characteristics compared to the rest of the skeleton that complicate the treatment of fractures. The jaw is composed of two bones joined in the midline by a symphysis (non-mobile joint). The roots of the teeth, nerves, blood vessels and salivary ducts are all inside the jaw and next to it. These structures usually suffer trauma with a mandibular fracture.
Clinical manifestations:
Symptoms of mandibular fractures include:
- refusal to eat
- bleeding from the mouth
- bad jaw alignment
- wounds around the mouth, pain and swelling in the area, mouth that remains open
- excess salivation that may be stained with blood.
Diagnosis:
Due to the inconvenience of this injury, the veterinarian may recommend sedation or anesthesia for the pet before palpating the injured area and doing more tests. Due to the minimum amount of soft tissues that cover the jaw, it is common for these fractures to be open. An open fracture is a fracture in which the protective layer of soft tissues around the bone opens, showing the edges of the broken bones outward.
Once the veterinarian determines that the pet is stable enough to focus on the tests and treatment of the mandibular lesion, x-rays of the jaw will be recommended to confirm if there is a fracture and guide treatment recommendations. Due to the complex anatomy of the jaw, teeth and skull, radiographs are usually performed under severe sedation or general anesthesia. This will reduce the stress of the pet and allow optimal placement to interpret the complicated images. In some cases, a CT scan may be recommended to obtain more information about the complex anatomy and determine the best surgical plan.
Treatment:
External immobilization may be placed. The reduction involves manipulation of bone fragments for alignment, with the aim of reducing discomfort. External immobilization is often a form of muzzle, either custom made from a medical tape or a commercial muzzle. In some cases, external immobilization is all that is needed for treatment.
Surgical treatment of mandibular fractures is recommended when the fracture is unstable, multiple fractures / chunks are present and / or both sides of the jaw are affected. Surgery is performed to restore adequate occlusion (normal scissor-type teeth interaction) of the teeth, improve well-being and aesthetic appearance, and provide a rapid recovery of function.
Many methods are available to treat mandibular fractures and the surgeon will determine which method is most suitable for the pet. Internal reduction and stabilization with bone plates and screws is a widely used surgical treatment. An incision is made in the region of the fracture, reducing (aligning) the fragments of the fracture and then stabilizing said fragments with a surgical bone plate and screws. Advantages include a rapid recovery of function and minimal postoperative care, compared to other techniques.
Another common surgical treatment involves using an external skeletal fixation (ESF). The ESF involves placing nails through the skin into the bone pieces and then connecting these nails to a connecting rod that gives stability, so that proper consolidation can occur. Most of the structure of the ESF is outside the animal and some postoperative care is necessary. The advantages of the ESF are that the structure can be placed in a less invasive way and, once the fracture is consolidated, the implants are completely removed. Other accepted surgical treatments include using splints inside the mouth, interosseous or interfragmentary wires, interdental wires or inter-interarred wires. In some cases, it may be recommended to place a feeding tube to reinforce nutrition while the fracture is welded.
Later Care and Evolution:
Possible complications include:
- defective dental occlusion
infection
- delayed / incomplete bone consolidation
- bone consolidation failure
Defective dental occlusion is the complication that occurs most frequently and can cause malfunction of the jaw joint, excessive wear of the teeth, injury to the tissues of the mouth surrounding the area, gum disease, pain and difficulty to eat Once defective dental occlusion occurs, its treatment is difficult.
Pain relievers are usually prescribed after treatment of a mandibular fracture. Many veterinary surgeons will also recommend a nonsteroidal anti-inflammatory drug (NSAID) specifically made for dogs or cats. In most cases, antibiotics will be prescribed due to the large number of open mandibular fractures.
Pets should not be allowed to play with toys or other animals, chew bones or do any activity that puts stress on the fracture site and puts them at risk of consolidation. If external immobilization is used, it may be recommended to inspect the muzzle site to check for irritation or accumulation of food debris, since dermatitis is common. In pets treated with immobilization or with fixation that limits the opening or closing of the mouth, it should be avoided that the pet has a lot of activity and limit the activity to the air at the coolest hours of the day. Dogs regulate body temperature by panting and if gasping with a muzzle or a closed mouth surgery technique is prevented, body temperature can rise rapidly.
Change in diet during recovery. If the pet consumes a dry tablet diet, it may be recommended to switch to a soft diet or soak the dry diet in warm water to soften the tablets before serving. This will reduce stress on the bones in consolidation and reduce trauma to soft tissues healing inside the mouth. In cases where feeding probes have been placed, instructions will be given to take care of the probe and feed through it.
Food residues may accumulate if splints are used inside the mouth, interdental wires, or inter-strand wires. You may be instructed to gently wash the pet's mouth on a regular basis to keep the site free of debris. If external skeletal fixators are used to stabilize the fracture, the device may need to be cleaned regularly and, in some cases, the fixators will be sold and may need regular bandage changes.
The prognosis is generally very good if complications are avoided. As stated earlier, a defective dental occlusion may cause additional procedures to be necessary (eg tooth reconstruction).
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