A long-term study of sinoscopic treatment of equine paranasal sinus disease: 155 cases (2012-2019)

BACKGROUND: There is little objective information concerning the intra- and post-operative complications or the long-term outcome of sinoscopic treatment of equine sinus disorders.

OBJECTIVES: To document the long-term outcome, including intra-operative complications, reasons for treatment failure and other complications, in horses undergoing standing sinoscopic treatment of sinus disorders.

STUDY DESIGN: Retrospective clinical study.

METHODS: Records of sinus disease cases presented to The University of Edinburgh Veterinary School between January 2012 and July 2019 were reviewed. Follow-up information was obtained from clinical records and a telephone questionnaire.

RESULTS: Long-term follow up for 155 cases treated sinoscopically showed that 108/155 (69.7%) fully responded to their initial treatment. Concurrent intranasal lesions were identified in 37.4% of cases. Sinusotomy was later required in 10 cases to improve surgical access or sinonasal drainage. Reasons for failure to fully respond to the initial treatment (n=47) included: intra-sinus bone sequestra (n=9), inspissated exudate (n=6) or insects (n=2); similar material and/or infected conchal bullae in the middle meatus (n=7); persistent oro-maxillary fistulae (n=4), misdiagnosed dental apical infections (n=4); impaired sinonasal drainage (n=4), progressive ethmoid haematoma regrowth (n=3) and undiagnosed causes (n=5). Further treatment of 43 of these cases (67% as outpatients) showed 34/43 cases fully responding to their second treatment. Only 4/155 cases (2.6%) required sinonasal fenestration. In the long term, 149/155 cases (96.1%) showed full and 2/155 cases (1.3%) showed partial improvement. Sinoscopy portal wound infection occurred in 9 cases.

MAIN LIMITATIONS: The length of time between treatment and obtaining follow-up information in some cases. Advances in knowledge and techniques over the duration of the study.

CONCLUSIONS: Sinoscopic treatment is a minimally-invasive technique causing minimal morbidity and was successful in 96.1% of cases. Meticulous care should be taken to ensure that bony sequestrae and inspissated exudate are fully removed from the sinuses and nasal cavity during sinoscopic treatments.