The Relationship of the Medial Maxillary Sinus Roof to the Sphenoid and Posterior Ethmoid Sinuses in Korean: A Radiologic Study

Lee, Seung Ju; Kwak, Min Young; Kang, Yong Kyung; Kim, Ji Sun

Abstract

BACKGROUND AND OBJECTIVES
The aim of this study was to perform radiologic study assessing the utility of the medial maxillary sinus roof (MMSR) as a reference point for providing a safe route of entry into the sphenoid and the posterior ethmoid sinuses in Korean patients.
SUBJECTS AND METHOD
We retrospectively reviewed 82 consecutive ostiomeatal computed tomographic scans of Korean adult patients performed from January 2014 to December 2014. Using the nasal floor as a reference point, the vertical distances to the highest MMSR, natural sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base were measured. Then the vertical distances from the highest MMSR to the sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base were calculated. The maxillary sinus to posterior ethmoid height ratio was calculated.
RESULTS
The average height of the highest MMSR relative to the nasal floor was measured to be 33.95+/-3.36 mm. The vertical distance from the highest MMSR to the natural sphenoid ostium, anterior sphenoid roof and floor and posterior ethmoid skull base was 1.87+/-3.52 mm, 11.77+/-3.30 mm, 6.09+/-3.16 mm, and 15.46+/-3.07 mm respectively. The mean ratio of the maxillary sinus to the posterior ethmoid height was 2.3+/-0.56.
CONCLUSION
The MMSR can be used as a reliable landmark to localize the natural sphenoid ostium and to enable a safe entry into the posterior ethmoid. Moreover, it provides a reasonable margin of safety from the skull base.