The Infra-Bullar Groove: Assessing a Novel Surgical Landmark for Identifying the Natural Maxillary Ostium

Functional endoscopic sinus surgery (FESS) is the gold-standard surgical treatment for chronic rhinosinusitis (CRS) not responding to appropriate medical therapy. Identifying the natural maxillary ostium (NMO) during FESS is often challenging due to the lack of definitive landmarks. To aid in the identification of the NMO, we describe and assess the feasibility of using a new surgical landmark, the infra-bullar groove (IBG), and evaluate its visibility and reproducibility during FESS. <b>Methods:</b> Video recordings of 41 maxillary antrostomy procedures in patients with varying severity of CRS were reviewed. Surgeons of different experience levels assessed IBG visibility and its termination at the NMO. <b>Results:</b> In video recordings where the ethmoid bulla was preserved during uncinectomy, the IBG and its connection to the NMO were successfully identified by all reviewers in 100% of analyzable cases. The mean time to IBG identification did not significantly differ among surgeons. The IBG was consistently more pronounced in cases with well-pneumatized bullae. <b>Conclusions:</b> Under controlled surgical conditions where the ethmoid bulla is preserved during uncinectomy, the IBG demonstrates high visibility and reproducibility for locating the NMO. However, further prospective studies are needed to establish its real-world utility and impact on surgical outcomes.