Oromaxillonasal Fistula in a Horse

Abstract

A 10-year-old mixed/breed mare was presented to the Veterinary Hospital of Uniderp/Anhanguera, in Campo Grande (MS), with signs of respiratory distress. The owner reported that the problem had been present for > 1-year. The horse was cachectic, anemic, and dyspneic with breathing limited to the right nostril. The horse also had halitosis and a bilateral mucopurulent nasal discharge (Fig. 1) Oral examination revealed a complicated crown fracture of the left maxillary fourth premolar tooth (208). Fragments of the tooth crown were displaced into the alveolus of 208. An oronasal fistula was present adjacent to the fractured 208 (Fig. 2). The sagittally oriented crown fragments of the 208 were removed. A large amount of food and debris was observed in the left maxillary sinus. Given the severity of the case, the recommendation of euthanasia was accepted by the owner.Post-mortem examination of the thoracic and abdominal cavities demonstrated no significant changes. However, examination of the oral cavity revealed areas of gingivitis and a large oronasal communication in the area surrounding 208.A cross-section of the head near the 208 alveolus showed food material and debris filling the left maxillary and conchal sinuses. The right nasal passage was narrow and compressed, with a clear deviation of the nasal canal and nasal septum secondary to the foreign material in the left maxillary and conchal sinuses (Fig. 3). The left mandibular fourth premolar tooth (308) was elongated 4-cm compared to other mandibular cheek teeth and contributed to compaction of the 208 crown fragments into the alveolus and the subsequent oronasal fistula (Fig. 3).