Paranasal sinus cysts in the horse: Complications related to their presence and surgical treatment in 37 cases.
Authors: Fenner M F, Verwilghen D, Townsend N, Simhofer H, Schwarzer J, Zani D D, Bienert-Zeit A
Journal: Equine veterinary journal
Summary
# Paranasal Sinus Cysts in Horses: Complications and Surgical Outcomes Paranasal sinus cysts frequently trigger secondary sinusitis in horses, yet their complications and long-term prognosis have received limited clinical documentation. This multicentre retrospective review examined 37 horses presenting with nasal discharge, facial swelling and epiphora, using radiography and CT to assess cyst-related tissue destruction and associated morbidities. Horses over 10 years old demonstrated significantly greater complications, including pressure-induced nerve damage (headshaking in 6 cases, unilateral blindness in 1), dental apex changes in 10 horses, and substantial bone resorption in 31 cases. Following surgical removal via osteotomy, 78.6% of the 28 horses with available follow-up data achieved full resolution, though post-operative complications occurred in 18 cases, most notably surgical site infection (11 horses) and nasofrontal suture periostitis (6 horses), with cyst recurrence in 18.9% of cases. The critical clinical message is that whilst uncomplicated cysts respond well to surgical treatment, long-standing cases in older animals develop serious secondary complications due to sustained pressure effects on facial structures and nerves that substantially worsen prognosis—emphasising the importance of early diagnosis and intervention, particularly in older horses where bone inflexibility may exacerbate progressive damage.
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Practical Takeaways
- •Paranasal sinus cysts carry a good prognosis when treated early via surgical osteotomy, with nearly 80% achieving full resolution in this series
- •Older horses (>10 years) are at substantially higher risk for pressure-induced complications affecting facial bones, teeth, and nerves; early intervention is critical in these cases
- •Plan for post-operative management of SSI and nasofrontal suture periostitis, which together occurred in 40% of surgical cases; recurrence monitoring is warranted as cysts return in approximately 1 in 5 horses
Key Findings
- •78.6% of horses (22/28) were fully cured following surgical treatment via osteotomy, with 14.3% partially cured and 7.1% showing no response
- •Post-operative complications occurred in 43.2% of cases (16/37), including surgical site infection (29.7%), nasofrontal suture periostitis (16.2%), and sequestration (2.7%)
- •Cyst recurrence occurred in 18.9% of cases (7/37) post-operatively
- •Horses over 10 years old demonstrated significantly more secondary complications including tissue destruction, nerve damage, and dental involvement than younger horses