Chronic upper respiratory tract diseases (URTD) such as common cold, sinusitis, and airsacculitis, are common health problems in captive orangutans (Pongo abelii, P. pygmaeus).2-7 A previous study identified chronic sinusitis as a primary stage of airsacculitis in captive orangutans.7 Comparable to human medicine, orangutans with diagnosed sinusitis that is unresponsive to long-term intensive medical treatment might be potential patients for minimally invasive functional endoscopic sinus surgery (FESS) to improve their wellbeing and to prevent further disease progression. Orangutans considered for FESS must be examined thoroughly, including a computed tomography scan (CT), to evaluate the upper respiratory tract to display individual anatomic structures. Anesthesia should be regarded as a high-risk immobilization, and anesthetized orangutans should be intubated in a sitting position immediately after induction to prevent pulmonary aspiration of pathologic exudates. For CT scanning, orangutans should be positioned in ventral recumbency for best display of possible fluid levels.6
The purpose of the surgery is to re-establish ventilation and mucociliary clearance of the sinuses. Preoperative medical management includes ten days of antibiotics according to drug resistance testing and a three-day course of steroids. The minimally invasive FESS technique also requires extensive training and specialized endoscopic and surgical instruments to ensure best surgical results.1 Preliminary results of the study in the captive European orangutan population revealed a promising long-term outcome of FESS as a treatment of chronic sinusitis and airsacculitis, thus increasing the welfare of orangutans suffering from chronic upper respiratory tract disease.
The authors thank especially Mr. T. Hoffmann; Anklin Ltd., Medical Supplies, Binningen, Switzerland; and Mr. C. Hartwig, Karl Storz GmbH & Co., for providing all the endoscopic equipment and technical support during the procedures. The work and organization of all participating zoos is gratefully appreciated.
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