The Lamella Ostium Extent Mucosa (LOEM) system: a new classification for endoscopic sinus surgery

In the last decades, various types of endoscopic sinus surgery (ESS) have emerged as treatments for chronic rhinosinusitis (CRS), particularly with the development of personalized, endotype-driven approaches targeting mucosal inflammation and remodeling. Despite these advancements, the literature reports heterogeneous and often divergent outcomes, leaving the actual benefit of more extensive surgical approaches in CRS control a matter of ongoing debate. This discrepancy stems from inconsistent definitions of surgical techniques, leading to variations in osseous and mucosal resections depending on patient phenotype, disease severity and surgeon preference. To address this inconsistency, the Japanese Rhinology Society introduced a classification based on procedure extent, but it lacks details on anatomical structures and mucosal treatment. Similarly, the ACCESS system measures ESS extent with postoperative CT-scans but overlooks mucosal interventions.