Sinus disease.

The diagnosis and treatment of diseases of the paranasal sinuses and conchae of horses are complicated by the large size of these structures, their complex anatomy, difficulties of access to them, and the advanced state of many diseases before diagnosis is made. Improved diagnostic methods include nuclear scintigraphy, computed tomography, and direct endoscopy of the sinuses. Treatment of some sinus diseases can be enhanced by access through direct sinus endoscopy for focal lesions, use of large frontal bone flaps for diffuse sinus lesions, standing surgery through a frontal flap for a variety of sinus disorders, and intralesional formalin for progressive ethmoidal hematomas.