Facial trauma in cats is primarily due to injuries caused by cars and falls from high levels (high-rise syndrome). Therefore, facial trauma is often associated with multiple injuries (multitrauma patient).¹

1. Anatomical Landmarks

The head is divided into two parts: the face and the cranium. The face is the most rostral part of the head, which does not engulf the brain case. In man, the face is divided into three levels: the lower level includes the mandibles, the lower lip, the floor of the mouth and the chin area; the middle face includes the upper maxilla, the upper lip, the nasal area, the lower eyelids and the cheeks from the lip commissure to the papillary line; the upper face starts from the papillary line to the hairs.

The face is located rostral to and slightly ventral to the brain case and acts as a shock absorber during trauma. Thick areas of bone determine pillars or buttresses which are providing 3-D mechanical resistance against distortion; they are divided into three principal areas: zygomatico-maxillary (lateral) buttress, nasomaxillary (medial) buttress, and pterygomaxillary (caudal) buttress. The lateral and medial buttresses are the most important in maintaining the vertical and sagittal dimensions of the face.

The mandibles are paired bones articulated to the skull based through the temporomandibular joint and unified rostrally by a strong fibrocartilaginous union, the symphysis. The caudal aspect of the mandible, the ramus and the condylar process, is covered by the thick masticatory muscles.

2. Initial Clinical Examination

In case of polytrauma associated with respiratory, circulatory or neurological disorders, clinical examination of facial lesions is postponed up until the animal's condition is stabilized. Oxygen therapy, perfusion and pain-killing therapy are maintained as long as necessary. Initial clinical examination should not be done at risk of deteriorating the cat's condition.

Initial facial examination, without general anesthesia, is aimed at observing:

 Cutaneous lesions (e.g., lip avulsion)

 Hemorrhage from nasal cavity, oral cavity or ear canal

 Ocular lesions

 Modification of dental occlusion indicating osteoarticular injuries

In a recent study in 84 cats which had sustained a high-rise syndrome, 94% of the cats survived and 66% of them suffered some degree of orofacial injury. Orofacial lesions which were identified included bilateral epistaxis, hard palate fracture +/- tear of palatal soft tissue, palatal soft tissue bruising, mandibular fracture, mandibular symphyseal separation, tongue injury, facial soft tissue injury, dental trauma, and other oral soft tissue injury.²

When neurological lesions are suspected, caution must be observed when manipulating the jaws to avoid exacerbation of potential skull base or cranial vault lesions, which are often associated with facial trauma. Whenever possible, a CT scan examination is strongly recommended prior to any therapy. A more detailed examination is undertaken only when the animal's condition is stabilized and general anesthesia can be induced. Placement of endotracheal tube and oxygen therapy is mandatory. In case of pharyngeal/laryngeal obstruction secondary to injuries, the tube is placed through a tracheostomy site. At that time, it is recommended to place an oesophageal tube in order to insure proper feeding of the animal prior to and after the surgery.

3. Evaluation of the Lesions Under Anesthesia

As soon as the animal is stabilized and pain controlled, general anaesthesia can be considered to allow better examination of oral structures and of the occlusion. Beyond the clinical detection of an abnormal mobility of the jaw bones, assessment of dental occlusion plays a primary role in evaluating the presence of osteoarticular lesions.

4. Diagnostic Imaging

Precise diagnostic imaging is essential in assessing the lesions prior to considering any treatment. Taking radiographs is the easiest means of evaluating hard tissue lesions and is readily available to most veterinary practitioners. However, precise evaluation of bone structures is rendered difficult by superimposition between right and left sides as well as between the mandible and the craniomaxillary complex. Detailed examination of a specific area is difficult except for the mandibular body and the teeth when using intraoral radiology techniques. To avoid the detrimental effects of superimposition, many different radiographic projections are required to demonstrate individual structures or regions within the skull. A complete skull study typically includes ventrodorsal (VD) or dorsoventral (DV), laterolateral (LL) and left and right lateral-oblique (OBL) projections. These projections can be completed by a laterolateral (LL) 15°-nose up for better evaluation of the TMJ.

Anatomic features easily identified on the DV radiograph include the zygomatic arch, dental occlusion, mandibular symphysis, and coronoid process. The mandibular body, frontal bone, temporal bone, and maxillary bone are easily identified on the OBL radiographs and the incisive bone, frontal bone, mandibular ramus, horizontal lamina of the palatine bone, nasal bone, condylar process, mandibular head, mandibular fossa, and ethmoid bone are easily identified on the LL radiograph, although it is impossible to determine sides because of superimposition of structures. Anatomic features that are very difficult or impossible to identify in all radiographs are the maxillary midline, horizontal lamina of the palatine bone, nasomaxillary suture, vomer bone, sphenoid bones, and pterygoid bone.³ Computed tomography (CT) has been shown superior to conventional radiography in detecting maxillofacial traumatic lesions. CT scans demonstrated 1.6 times more maxillofacial injuries for dogs and 2.0 times more for cats than conventional radiographs.³

Adapted from ³

Clinical and radiographic examinations are more likely to pick up the easiest lesions to detect. When using CT scan imaging, in 36% of dogs or cats presenting with symphyseal dysjunction or mandibular body fractures, which can readily be detected by radiographs, 1 to 6 other trauma can be detected.³

Thorough assessment of maxilla-facial lesions secondary to trauma is essential in deciding the treatment approach. Nonsurgical as well as surgical treatments can both be used when dealing with maxilla-facial trauma cases, keeping in mind that in animals, reestablishment of function rather than esthetics is the main goal.

References

1.  Vnuk D, Pirkić B, Maticić D, Radisić B, Stejskal M, Babić T, Kreszinger M, Lemo N. Feline high-rise syndrome: 119 cases (1998–2001). J Feline Med Surg. 2004;6(5):305–312.

2.  Bonner SE, Reiter AM, Lewis JR. Orofacial manifestations of high-rise syndrome in cats: a retrospective study of 84 cases. J Vet Dent. 2012;29(1):10–18.

3.  Bar-Am Y, Pollard RE, Kass PH, Verstraete FJ. The diagnostic yield of conventional radiographs and computed tomography in dogs and cats with maxillofacial trauma. Vet Surg. 2008;37(3):294–299.