Trephination versus Minimally Invasive Transnasal Approaches for the Diagnosis and Treatment of Sinus Disease in Horses

SIMPLE SUMMARY: The horse’s upper respiratory tract contains several sinus cavities, and the infection of these sinuses (sinusitis) can be encountered due to various reasons. Several different diagnostic and treatment options have been descripted in the last few decades to facilitate prompt and correct diagnosis and treatment. With advances in the development of several diagnostic tools, for example three-dimensional imaging (e.g., standing computer tomography) and small-diameter video endoscopes, new therapeutic techniques are constantly being introduced. This report aims to highlight the advantages and disadvantages of several invasive and minimally invasive techniques to enter the affected sinuses in a retrospective clinical study. Nearly half of the cases presented here could be entered and subsequently treated through the nose by the use of a small-diameter video endoscope without additional intervention. However, in cases where surgery was required, minimally invasive techniques seemed to be as effective in resolving clinical signs as more invasive approaches. While proper case selection is crucial for success, these experiences point towards the fact that minimally invasive transnasal approaches should be considered more commonly for the diagnosis and treatment of horses presenting with sinusitis in the future. ABSTRACT: This retrospective case series aims to highlight the advantages and disadvantages of different treatment options for sinus disease in horses, with a special focus on surgical approaches. The medical records of 25 horses with sinusitis which presented to the equine hospital, Vetmeduni Vienna, between August 2020 and January 2022 were analysed. In 11 cases, conservative treatment by the transnasal endoscopic lavage of the affected sinuses through the sinonasal channel or through a developed, pre-existing sinonasal fistula was performed. In the remaining 14 cases, openings into the sinus for subsequent lavage were surgically created either via classical trephination/bone flaps (8) or by transnasal endoscopically guided minimally invasive approaches (8). In some cases (2), a combination of classical extra-nasal and minimally invasive transnasal approaches was required. The minimally invasive techniques used were comprised of laser surgery (3), electrosurgery (3) and balloon sinoplasty (2). The sinusitis and underlying diseases were successfully treated in all of the horses until hospital discharge. Long-term follow-up could be obtained only from a small number of patients due to the temporal proximity (the study began two years ago) to their initial discharge from the hospital, but they showed the continuous resolution of clinical signs in all cases in which follow up data were available. The results of this case series indicate that if surgical intervention is required, minimally invasive techniques appear to be a promising and potentially cheaper alternative to classical extra-nasal approaches for the treatment of sinus disease in selected cases. In the future, the use of these techniques should be considered more commonly with the broader availability of improved endoscopes and instruments. Additionally, by using small-diameter endoscopes, the need for any surgical intervention might be significantly reduced in many cases.