Objectives: To examine the frequency in which angled endoscopes are necessary to visualize the true maxillary ostium (TMO) following uncinectomy and prior to maxillary antrostomy. Additionally, to identify preoperative computed tomography (CT) measures that predict need for an angled endoscope to visualize the TMO.
Study design: Retrospective study.
Setting: Tertiary academic hospital.
Patients and methods: Patients who underwent endoscopic sinus surgery (ESS) between December of 2017 and August of 2018 were retrospectively identified. Cases were reviewed if they were primary ESS cases for chronic rhinosinusitis without polyposis and if they were at least 18 years of age.
Results: Sixty-three maxillary antrostomies were reviewed (82.5% were from bilateral cases). Thirty-five cases (55.6%) required an angled endoscope in order to visualize the TMO. Of the preoperative CT measures examined, a smaller sphenoid keel-caudal septum-nasolacrimal duct (SK-CS-NL) angle was significantly associated with need for an angled endoscope intraoperatively to visualize the TMO (17.1° SD ± 3.2 vs 15.0° SD ± 2.9; P = .010).
Conclusion: Angled endoscopes are likely required in the majority of maxillary antrostomies to visualize the TMO. This is important to recognize in order to prevent iatrogenic recirculation. The SK-CS-NL angle may help to identify cases preoperatively which require an angled endoscope to identify the TMO during surgery.
Keywords: chronic rhinosinusitis; endoscopic sinus surgery; maxillary ostium; maxillary sinus; nasal endoscopy; recirculation.