Transendoscoplc resection ol pharyngeal cysts in the standing horse

Abstract

Pharyngeal cysts are uncommon in horses (Koch and Tate, 1978; Shoemaker and Haynes, 1992). They might be congenital remnants of the thyroglossal duct or of inflammatory or traumatic origin (Koch and Tate, 1978; Stick and Soles, 1980; Haynes et al., 1990; Robertson, 1991; Shoemaker and Haynes, 1992). Suggestive clinical symptoms are an inspiratory and/or exspiratory noise, exercise intolerance, nasal discharge and dysphagia (Koch and Tate, 1978; Robertson, 1991; Tulleners, 1991; Shoemaker and Haynes, 1992; Speirs et al., 1992). In the year 1995 four horses of different breeds between two and eight years of age were diagnosed with pharyngeal cysts in the Clinic of Ruminant and Equine Medicine. The diagnosis was made by endoscopic visualization in ail cases. In two horses the general appearance was only slightly altered. Two patients were presented with coughing, nasal discharge and dysphagia. Their general appearance was moderatley to severly altered. One horse was presented with an intermitient epiglottic entrapment and one horse with a permanent epiglottic entrapment in addition to the pharyngeal cyst. In all cases exstirpation of the cyst was performed transendoscopically in the standing horse after sedation with detomidin (8mg/500 kg bodyweight intravenous; Domosdean, Graub AG) in combination with butorphanol (10 mg/500 kg bodyweight intravenous; Morphasol, Graub AG) and local anesthesia of the pharynx (Lidokain Losung 10% reuli). For transendoscopic resection of the cyst a wire snare (SD-16U, Olympus AG) was fixed at the base of the cyst via a transnasal or transoral approach. Excision was done electrosurgically with a high frequency generator (UES 10; Olympus AG) connected to the wire snare. In three cases it was possible to excise the cyst at its base. In one horse the cyst was only partially removed to avoid perforation of the soft palate. Postoperative therapy consistet of sodium penicillin (30,000 IU/kg bodyweight), gentamicin (5 mg/kg bodyweight) and flumethason (2.5 mg/ kg bodyweight) twice daily via an intravenous catheter. Duration of this therapy was adapted to the recovery period of the individual horse. All horses returned to their prior use within two to four weeks. Because of the simple technique and the good results the transendoscopic electrosurgical resection of pharyngeal cysts in the standing horse has to be considered an alternative therapy to other procedures.