Extra‐nasal approach to access the dorsal and ventral conchal bullae in horses

Abstract

SummaryNasal conchal bulla empyema can be found in up to 20% of horses with paranasal sinus disease but remains difficult to diagnose and can result in persistent unilateral discharge before presentation. Our aim in this experimental ex vivo study was to describe two extra‐nasal approaches to access the nasal conchal bullae. Six cadaveric heads were used to determine the ideal landmarks to access the dorsal and ventral conchal bullae through two rhinocenteses performed with the aid of a 14G needle and a mallet through the maxillary bone, and to access both bullae simultaneously through a 13‐mm diameter trephination. Both techniques were performed bilaterally. To assess correct placement of the rhinocenteses and trephination, each bulla was injected with a coloured insulating foam before performing a maxillary bone flap to inspect the bullae. Both bullae were successfully entered with the 14G needle in all instances. The nasolacrimal duct was damaged while entering the ventral conchal bulla in 3/12 approaches. Trephination of the maxillary bone allowed access to both nasal conchal bullae in all cases but one, where the portal was placed too dorsally and did not allow access to the ventral conchal bulla. The opening created with the trephine could allow the use of a small instrument such as a rongeur which could have diagnostic and therapeutic benefits. The limitations are that this was an ex vivo study and nasolacrimal duct damage could have clinical repercussions if the duct becomes obstructed after accessing the ventral conchal bulla. It was concluded that the techniques described are simple, minimally invasive and provide access to the conchal bullae for diagnostic and therapeutic purposes. Additionally, they may reduce the need for CT or laser for the diagnosis and treatment of bulla empyema.