The pneumatization and adjacent structure of the posterior superior maxillary sinus and its effect on nasal cavity morphology

Abstract

Background: The aim of this study was to observe the pneumatization degree and adjacent structure of the posterior supe-rior maxillary sinus (PSMS) and its effect on nasal cavity morphology. Material/Methods: The study included a total of 103 cases whose paranasal sinus CT scans had been analyzed. The pneumati-zation of the PSMS and its relationship with posterior ethmoid sinus (PEs) and sphenoid sinus (SS) were ob-served. The effects of the pneumatization of PSMS on nasal cavity width and morphology also were evaluated. Results: 1) The PSMS was adjacent to orbit or middle nasal meatus (MNM) as type I in 5.82% of cases. The PSMS was adjacent to the orbit and superior nasal meatus (SNM) as follows: the superior part of medial wall of maxillary sinus (MMS) was not abutting on PEs as type II (4.35%) and abutting on PEs as type III (85.9%). If the type III was not accompanied by MMS shift toward medial it was identified as type IIIa (33.50%), and if it was accom-panied MMS shift toward medial, it was identified as type IIIb (45.63%). The ethmomaxillary sinus (EMS) was identified as type IIIc (6.80%). The PSMS directly abutted on the SS as type IV in (3.88%). 2) The higher the de-gree of the pneumatization of PSMS was, the narrower the width of the upper part of the posterior nasal cav-ity (p<0.05 respectively). Conclusions: The relationship of PSMS with the orbit, SNM, PEs, and SS should be identified pre-operation; it is important for safety and complete removal of retromaxillary lesions during endoscopic sinus surgery. The pneumatiza-tion degree of PSMS also should be considered as it can influence the morphology of posterior nasal cavity.