Several intraoperative processes and postoperative adverse events contributed additional predictive information for prolonged LOS, after consideration of preoperative patient characteristics.

The etiology of maxillary sinus mucoceles is not well understood. Mechanical obstruction or allergy or both do not seem to play an important role. An infectious origin is also not supported by the above data. Endoscopic sinus surgery is a reliable therapeutic measure with a favorable long-term outcome.