Fenestration of the maxillary septal bulla using different surgical approaches and endoscopy systems in horses: An ex vivo study.

Sinusitis is common in horses. Sinoscopy is used for visualization of sinus cavities and can be used for diagnostic and therapeutic purposes. In this surgical procedure, a larger chamber is created and communication with other sinus compartments facilitated. To compare the applicability of different surgical approaches and rigid endoscopy systems for sinus inspection and fenestration of the maxillary septal bulla, and to examine the impact of different lens angles on the effectiveness of the procedure. Six chemically preserved cadaveric equine heads were used. Frontal and caudal maxillary portals were tested. Portals were created in the right and left antimeres of each specimen, over the frontal and the caudal maxillary sinus. Two types of rigid 4 mm endoscopes (0º and 30º) were used. The comprehensiveness of sinus examination and the applicability of portals for fenestration of the maxillary septal bulla were evaluated. Satisfactory exploration of sinus cavities and structures of interest was achieved in all specimens. Fenestration of the maxillary septal bulla was successfully accomplished using frontal portals as viewing portals and caudal maxillary portals as instrument portals. When caudal maxillary portals were used as viewing portals, endoscope maneuverability was limited by the infraorbital canal in 50% of antimeres. When frontal portals were used as instrument portals, the frontomaxillary opening interfered with or prevented appropriate fenestration of the bulla in 83.33 % and 16.66 % of antimeres respectively. Ideally, frontal portals should be used as viewing portals and caudal maxillary portals as instrument portals for successful fenestration of the maxillary septal bulla.