Paranasal sinus cysts in the horse: Complications related to their presence and surgical treatment in 37 cases.

Overall, the diagnosis and treatment of sinus cysts is relatively straightforward and carries a good prognosis. In long-standing cases complications secondary to the expansive growth of cysts will dramatically affect the prognosis for full recovery due to pressure-induced changes to facial bones, cheek teeth and nerves. These secondary complications mainly occurring in older horses may be due to a combination of a relatively longer period of affection and the inflexibility of older horses' bones. Cyst recurrence following treatment can occur in up to 19% of cases.