Abstract
OBJECTIVE
To describe a reliable anatomical landmark to identify the maxillary sinus natural ostium during endoscopic surgery (traditional or minimally invasive).
METHOD
An anatomical and radiological study in which we evaluated the presence of an anatomical landmark through dissections of 10 cadaver heads and with tridimensional reconstructions of 50 computer tomography (CT) exams of patients with sinonasal inflammatory problems. The dissections were performed by the same surgeon and using traditional endoscopes (0-degree and angled), as well as traditional instruments. Each head was dissected at both sides, so 20 sides were dissected. The CT scans were selected from 20 patients with sinonasal inflammatory from our institution's ambulatory center. The exams had a maximum thickness of 1 mm and were tridimentionally reconstructed using a computer program (Realia Intage).
RESULTS
The anatomical landmark, the ‘m‘ line, which is a line from the most inferior aspect of the ethmoid bulla to the nasal lateral wall, was reliable and crossed the maxillary sinus natural ostium in every dissection and CT reconstruction.
CONCLUSION
The ‘m‘ line points toward the maxillary sinus natural ostium and can be useful to surgeons during maxillary sinus surgery, either traditional or minimally invasive, such as in balloon sinuplasty.