Angle between anterior and medial maxillary sinus wall is an additional predictive factor for enhanced visibility during pre-lacrimal window approach

Introduction and Aims Endoscopic-endonasal approach to the anterior wall of the maxillary sinus is particularly difficult. The recently introduced prelacrimal window approach (PLWA) provides a wide access to this challenging location with a low complication rate. To perform a PLWA, the distance between the anterior wall of the maxillary sinus and the nasolacrimal duct must be a certain distance. Another factor that can influence the endoscopic access to the anterior wall of the maxillary sinus during a PLWA is the angle between the anterior and medial wall of the maxillary sinus. A more acute angle favors the visibility of the anterior maxillary sinus wall. This antero-medial maxillary sinus angle (AMMSA) has not yet been measured in this context.

Methods The AMMSA was retrospectively measured in 100 randomly selected NNH-CT scans (n=200) from CRSsNP patients. The methodology of measurements was analogous to Simmen et al. Furthermore, the AMMSA was divided into two visibility types (type A: < 70° and type B:≥70°).

Results The whole cohort presented an AMKW of 68.6° (SD 5.9; 52-88). In 5% there was an AMMSA of more than 80°. Type-A ( < 70°) was found in 59.5% and type-B (≥70°) was found in 40.5%.

Conclusion The AMKW shows a relatively constant value around 68°. In a few cases, however, a significantly larger AMKW is found, which can significantly limit the visibility and accessibility of the anterior wall of the maxillary sinus during the perfomance of a PLWA.

Poster-PDF A-1467.pdf

Publication History

Article published online:
13 May 2021