EQUINE VETERINARY JOURNAL Equine vet. J. (2005) 37 (2) 138-142
Modified frontonasal sinus flap surgery in standing horses: surgical findings and outcomes of 60 cases
G. C. QUINN, J. A. KIDD† and J. G. LANE* Department of Clinical Veterinary Science, University of Bristol, Langford, Avon BS40 5DU, UK. Keywords: horse; sinus; frontal flap; empyema; sinus cyst; ethmoidal haematomaSummary Reasons for performing study: 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 boneflap is necessarily discarded. Objectives: To assess whether the modified standing frontonasal flap (SFF) surgery offers an effective method to investigate and/or treat sinunasal disorders in the horse. Methods: 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 longterm outcomes, including cosmetic effect. Results: 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. Conclusions: The modified SFF technique was found to bepracticable 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 haemorrhagein 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. Potential relevance: The modified SFF technique is a valuable alternativeto other invasive methods of sinunasal surgery. Introduction Advances in techniques, together with improved agents for sedation
and analgesia, have allowed an increasing number of equine disorders to be evaluated and treated with the horse standing. This includes the investigation and treatment of equine nasal and paranasal sinus disorders (Lane 1987; Ford 1991; Ruggles et al. 1993; Schumacherand Crossland 1994; Schumacher et al. 1998, 2000), so that surgery of these structures under general anaesthesia is likely to be reserved for the more invasive procedures. The clinical features of sinunasal disorders are usually dominated by a nasal discharge, which is almost invariably unilateral and where the nature varies from mucoid to purulent. Other signs may include epistaxis, facialdeformity, malodorous breath, ocular discharge, abnormal respiratory noise and altered nasal airflow. However, the latter are normally features of expansive lesions or where there is impairment or obstruction of the normal drainage mechanisms (Tremaine and Dixon 2001a). A variety of surgical approaches have been described to access the individual sinus compartments. However, where wide exposure is neededto enter multiple sinus compartments, the frontonasal route via the conchofrontal sinus (CFS) is a more versatile approach than the lateral maxillary approach (Lane 1993; Schumacher and Crossland 1994; Schumacher et al. 1998, 2000; Freeman 2003). Correct positioning of the osteoplastic flap permits the breakdown and removal of the intercompartmental septum so that access can be gained to the...