Modified frontonasal sinus flap surgery in standing horses: surgical findings and outcomes of 60 cases

Abstract

Previous studies of sinus surgery on standing horses have been based on techniques which utilise powered hand bone saws and preserve the bone flap, which was thought to be essential for a good cosmetic result. This report describes a simplified technique applied to the standing horse where the sinus flap construction used a large skull trephine and where the bone flap is necessarily discarded. To assess whether the modified standing frontonasal flap (SFF) surgery offers an effective method to investigate and/or treat sinunasal disorders in the horse. The case records of 60 horses subjected to modified SFF surgery were reviewed to analyse the efficacy of the technique when applied to a range of sinunasal disorders in terms of diagnosis, surgical findings, complications and long-term outcomes, including cosmetic effect. Resolution of clinical signs was achieved in 54 out of 60 horses, and for the remainder the SFF technique proved useful on a diagnostic basis. The cosmetic result was, in the opinion of the owners, excellent or satisfactory in 48 of 56 (86%) horses. The modified SFF technique was found to be practicable and provided satisfactory exposure of the sinus contents for diagnosis and removal of diseased tissue in a range of disorders. An acceptable cosmetic result can be obtained in the majority of horses despite rejection of the disc of overlying bone. Apart from avoiding the risks associated with general anaesthesia, the advantages of the modified SFF sugery are: a reduction of haemorrhage in the standing horse; reduced mucosal engorgement; straightforward anatomical orientation; a comfortable working height; and reduced surgery time. A sound knowledge of the functional anatomy of the area is a prerequisite before embarking on any form of sinunasal surgery. Complications are infrequent and usually transient. The modified SFF technique is a valuable alternative to other invasive methods of sinunasal surgery.