Computed tomographic findings in 1600 cases of equine sinonasal disease and associations with case outcome

BACKGROUND: No study has described the computed tomographic (CT) sinonasal findings in a large cohort of referred sinonasal disease cases. OBJECTIVES: To report the CT imaging findings in equine sinonasal disease and examine associations between case outcome and CT findings. STUDY DESIGN: Retrospective case series. METHODS: Data were collected from medical records from 19 equine hospitals on sinonasal disease cases which had undergone CT imaging. Case outcome was obtained from clinical records, and/or by contacting clients and referring veterinarians. Multivariable logistic regression analysis was used to examine variables at presentation associated with case outcome. RESULTS: The 1600 cases of sinonasal disease had unilateral sinusitis in 1457 and bilateral sinus disease in 143. The rostral maxillary sinuses (86.1% affected) and ventral conchal sinuses (74.8% affected) were most commonly involved. Fluid attenuation or distortion of the ventral nasal conchal bullae (NCB) was present in 21.3% and 39.3% of cases, respectively, and of the dorsal NCB, in 16.5% and 28.4% of cases, respectively. Hyperostosis (inflammatory thickening) of sinus-related bones was mild in 35.5%, moderate in 19.8%, severe in 8.7%, and absent in 36.1% of cases. A total of 659 non-fractured and 200 fractured apically infected teeth were found. The normal contralateral sinuses in 100 horses showed CT evidence of endodontic/apical infection in 114 cheek teeth. The multivariable model was built with data from 674 cases. Cases with apically infected non-fractured (odds ratio [OR] 2.15, 95% confidence interval [CI] 1.41-3.29) or fractured teeth (OR 2.03, 95% CI 1.08-3.81) (i.e., dental sinusitis) had a higher likelihood of cure than those that did not. Cases with caudal group sinusitis (OR 0.48, 95% CI 0.29-0.80) or moderate or severe bone hyperostosis (OR 0.53, 95% CI 0.36-0.78) had a lower likelihood of cure than those without. MAIN LIMITATIONS: Retrospective study with incomplete data available for some cases. CONCLUSIONS: Maxillary cheek teeth endodontic/apical infection does not always cause sinusitis. Sinus bone hyperostosis and caudal group sinusitis are associated with a lower likelihood of cure, whereas apical infections are associated with a higher likelihood of cure.