History and Physical Examination Findings
A 2-year-old 29.6-kg (65.2-lb) castrated male Coonhound was evaluated after sustaining acute trauma to the face as a result of being kicked by a horse. The patient had no pertinent medical history. On initial evaluation, facial asymmetry with considerable soft tissue swelling of the left dorsal maxillary region, a 10-mm laceration of the skin overlying the left maxilla, and bilateral epistaxis were present. Remaining findings on physical, neurologic, and oral examination were unremarkable.
The patient was monitored overnight, and appropriate analgesics were administered. The following day, facial swelling was improved, although a shallow concave depression in the area of the left nasal, frontal, and maxillary bones and at the medial canthus was noted. No radiographic imaging was performed at that time.
One week later, the patient was referred for further investigation following the development of sneezing. The patient had adequate nasal airflow bilaterally, although several nonproductive sneezing episodes were noted. The swelling on the muzzle had decreased, compared with swelling seen during the initial evaluation, and the shallow concave depression in the left maxillofacial region was still present (Figure 1).
Photograph of a 2-year-old Coonhound evaluated after sustaining acute trauma to the face as a result of being kicked by a horse (the hair has been clipped in preparation for surgery). There is a shallow concavity in the dorsal maxillary region and a small skin laceration overlying the left maxilla.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Photograph of a 2-year-old Coonhound evaluated after sustaining acute trauma to the face as a result of being kicked by a horse (the hair has been clipped in preparation for surgery). There is a shallow concavity in the dorsal maxillary region and a small skin laceration overlying the left maxilla.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Photograph of a 2-year-old Coonhound evaluated after sustaining acute trauma to the face as a result of being kicked by a horse (the hair has been clipped in preparation for surgery). There is a shallow concavity in the dorsal maxillary region and a small skin laceration overlying the left maxilla.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Results of a CBC and serum biochemistry analysis were unremarkable. The patient was anesthetized, and CT of the head was performed (120 kV, 100 mA, and 0.8-second rotation). A transverse image and a 3-D reconstruction obtained with 1.3-mm contiguous images are provided (Figure 2).
Transverse CT image of the head of the dog in Figure 1 obtained at the level of the distal root of the maxillary fourth premolar teeth (A) and a 3-D reconstruction of the head obtained with 1.3-mm contiguous images (B).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Transverse CT image of the head of the dog in Figure 1 obtained at the level of the distal root of the maxillary fourth premolar teeth (A) and a 3-D reconstruction of the head obtained with 1.3-mm contiguous images (B).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Transverse CT image of the head of the dog in Figure 1 obtained at the level of the distal root of the maxillary fourth premolar teeth (A) and a 3-D reconstruction of the head obtained with 1.3-mm contiguous images (B).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
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Diagnostic Imaging and Interpretation
There were multiple comminuted depression fractures of the left maxilla and the dorsomedial aspect of the right maxilla, right and left nasal bones, and rostral portions of the left and right frontal bones, resulting in many variably sized osseous fragments within the left and right nasal cavities. The nasal septum also had multiple fractures and was deviated toward the right. The depression of the fracture fragments had substantially decreased the volume of the nasal cavity. The left globe and retrobulbar structures and the cribriform plate were intact. Soft tissue overlying the fractures was thickened and irregular, and multiple pockets of subcutaneous emphysema were present. As seen on the 3-D reconstruction, the frontal, maxillary, and nasal bones had a fracture pattern centered at the midline of the face and radiating out toward the periphery, consistent with the reported nature of the trauma. Four large fracture fragments and multiple small fragments were visible. The depression of the fracture fragments would have resulted in concavity of the dorsal surface of the skull when all swelling had resolved. The contour of the orbit was also altered by the fracture pattern and fragments (Figure 3).
Same images as in Figure 2. A—On the transverse CT image, notice the multiple comminuted fractures of both maxillae, more severe on the left, with severe compression of the nasal cavity by the fracture fragments. The nasal septum is also fractured and deviated mildly to the right at this level (white arrow). There is increased soft tissue opacity in the nasal cavity, representing hemorrhage and swelling. B—On the 3-D reconstruction, notice the extent of the comminuted maxillofacial fractures and compression of the nasal cavity. Although the bones of the left orbit were involved, the globe itself was intact, as was the cribriform plate. The reconstructed view allowed identification of 4 large fracture fragments that required realignment (black arrows).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Same images as in Figure 2. A—On the transverse CT image, notice the multiple comminuted fractures of both maxillae, more severe on the left, with severe compression of the nasal cavity by the fracture fragments. The nasal septum is also fractured and deviated mildly to the right at this level (white arrow). There is increased soft tissue opacity in the nasal cavity, representing hemorrhage and swelling. B—On the 3-D reconstruction, notice the extent of the comminuted maxillofacial fractures and compression of the nasal cavity. Although the bones of the left orbit were involved, the globe itself was intact, as was the cribriform plate. The reconstructed view allowed identification of 4 large fracture fragments that required realignment (black arrows).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Same images as in Figure 2. A—On the transverse CT image, notice the multiple comminuted fractures of both maxillae, more severe on the left, with severe compression of the nasal cavity by the fracture fragments. The nasal septum is also fractured and deviated mildly to the right at this level (white arrow). There is increased soft tissue opacity in the nasal cavity, representing hemorrhage and swelling. B—On the 3-D reconstruction, notice the extent of the comminuted maxillofacial fractures and compression of the nasal cavity. Although the bones of the left orbit were involved, the globe itself was intact, as was the cribriform plate. The reconstructed view allowed identification of 4 large fracture fragments that required realignment (black arrows).
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
The extent of fracture displacement and comminution was surprising given the patient's relatively limited physical examination abnormalities and clinical signs but was consistent with the severity of trauma observed by the client. The degree of fragment displacement, presence of fracture fragments within the nasal cavity, and clinical signs in the patient were all indications for maxillofacial reconstructive surgery.1,2
Treatment and Outcome
Following CT, the patient was taken to surgery, where a 140-mm longitudinal incision was created on the dorsal midline of the face. A large hematoma was seen overlying the most severely compressed fracture fragments. After the 4 major fragments were elevated, the nasal cavity was carefully debrided and copiously flushed, and all small detached fragments of bone were removed. Vital bone fragments were realigned and secured in place with titanium miniplates and screws contoured to the patient's normal anatomy.2,3
On postoperative CT images obtained after maxillofacial reconstructive surgery had been performed, restoration of the normal nasal sinus space and contours of the maxillae could be seen (Figure 4). The fracture fragments were held in good alignment with various titanium miniplates and screws. A stent bandage was placed to minimize postoperative emphysema around the surgery site.
Postoperative CT images of the dog in Figure 1. A—On a transverse CT image obtained at the level of the mesial roots of the maxillary first molar teeth, the contour of the maxilla has been restored, with normal volume of the nasal cavity and no bony fragments remaining within the nasal cavity. Soft tissue opacities in the nasal cavity, consistent with hemorrhage and lavage fluid from the procedure, remain evident. A cross-section of a titanium miniplate and screws can be seen (white arrow). B—On a 3-D reconstruction, the final surgical outcome can be appreciated. Reconstruction of the maxillofacial contour was accomplished with various-sized titanium miniplates and screws, allowing for an immediate return to function and a good cosmetic outcome for the patient.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Postoperative CT images of the dog in Figure 1. A—On a transverse CT image obtained at the level of the mesial roots of the maxillary first molar teeth, the contour of the maxilla has been restored, with normal volume of the nasal cavity and no bony fragments remaining within the nasal cavity. Soft tissue opacities in the nasal cavity, consistent with hemorrhage and lavage fluid from the procedure, remain evident. A cross-section of a titanium miniplate and screws can be seen (white arrow). B—On a 3-D reconstruction, the final surgical outcome can be appreciated. Reconstruction of the maxillofacial contour was accomplished with various-sized titanium miniplates and screws, allowing for an immediate return to function and a good cosmetic outcome for the patient.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
Postoperative CT images of the dog in Figure 1. A—On a transverse CT image obtained at the level of the mesial roots of the maxillary first molar teeth, the contour of the maxilla has been restored, with normal volume of the nasal cavity and no bony fragments remaining within the nasal cavity. Soft tissue opacities in the nasal cavity, consistent with hemorrhage and lavage fluid from the procedure, remain evident. A cross-section of a titanium miniplate and screws can be seen (white arrow). B—On a 3-D reconstruction, the final surgical outcome can be appreciated. Reconstruction of the maxillofacial contour was accomplished with various-sized titanium miniplates and screws, allowing for an immediate return to function and a good cosmetic outcome for the patient.
Citation: Journal of the American Veterinary Medical Association 242, 2; 10.2460/javma.242.2.161
The patient recovered well after surgery and was eating the next morning. Analgesics and antimicrobial medications were continued after surgery. At the time of suture removal 14 days after surgery, the incision site had healed completely, and no abnormalities could be detected on physical or ocular examination. Further follow-up discussions with the client in the 6 months after surgery revealed that the patient had returned to its normal energy level, with resolution of all sneezing episodes, normal findings on ophthalmologic examination, and no detectable facial asymmetry. Skull radiographs obtained 7 months after surgery showed fracture healing; the titanium plates and screws were in appropriate positions.
Comments
The extent of maxillofacial trauma can be difficult to assess in awake patients owing to pain, swelling, and temperament of the patient. Following acute trauma, efforts should first concentrate on stabilizing the patient's condition, addressing life-threatening injuries or bleeding, and obtaining adequate pain control. Once the patient's condition is stabilized, any maxillofacial fractures should be diagnosed and addressed as soon as possible after the trauma has occurred because any delay in repair will result in the formation of fibrous adhesions that make adequate realignment of the fragments more difficult.1,2,4 The standard in human medicine is to repair most maxillofacial fractures within 2 to 3 days after the patient has been medically stabilized and the initial swelling has decreased.1
In patients in which damage to the maxillary, incisive, nasal, frontal, or zygomatic bones is suspected, CT images of the head are indicated for diagnosis and treatment planning.5 The ability to obtain usable data from skull radiographs is limited because of overlapping structures and the presence of sinus spaces and air-filled cavities. It has been demonstrated that fractures that are easily identifiable on CT images are frequently missed on conventional radiographs.5 Furthermore, treatment planning becomes clearer with the use of 3-D reconstructions. Potential complications of undiagnosed facial fractures in dogs and cats include malocclusion, chronic sinusitis, and cavitation of the fracture defect as well as impaired ocular movement and stenosis of the nasolacrimal duct, depending on fracture location and severity.2
In this case, the external facial swelling masked the true extent of the facial damage. Radiographic images of the head would likely not have been sufficient for detection of several critical fracture fragments that were removed or realigned on the basis of information obtained by means of CT. It was only with CT that it was possible to appreciate the impact of the trauma on the maxillofacial region. The use of 3-D reconstructions can also assist with treatment planning. Such images allow surgeons to be thorough in their debridement without being overly invasive by visualizing bone fragments otherwise hidden in areas of hemorrhage and swelling. This minimizes the likelihood of potential complications such as chronic sinusitis and sequestrum formation, which can occur if these fragments were inadvertently missed. Postoperative imaging allowed us to clearly identify reestablishment of the normal nasal contour. The use of CT in patients with maxillofacial trauma continues to be an excellent means of diagnosing fractures and formulating treatment plans for fracture management.
References
1. Sharabi SE, Koshy JC, Thornton JF, et al. Facial fractures. Plast Reconstr Surg 2011; 127:25e–34e.
2. Boudrieau RJ. Maxillofacial fracture repair using miniplates and screws. In:Verstraete FJM, Lommer MJ, eds. Oral and maxillofacial surgery in dogs and cats. Oxford, England: Elsevier Saunders, 2011;305–321.
3. Rahn B. Bone healing: histologic and physiologic concepts. In: Sumner-Smith G, ed. Bone in clinical orthopedics. 2nd ed. New York: Thieme, 2002;287–326.
4. Boudrieau RJ. Fractures of the maxilla. In:Johnson AL, Houlton JEF, Vannini R, eds. AO principles of fracture management in the dog and cat. Davos, Switzerland: AO Publishing, 2005;116–129.
5. Bar-Am Y, Pollard RE, Kass PH, et al. The diagnostic yield of conventional radiographs and computed tomography in dogs and cats with maxillofacial trauma. Vet Surg 2008; 37:294–299.
