Authors' Classification of Sphenoid Sinus Pneumatizations into the Sphenoid Bone Processes.

Background

The varied shape and size of the sphenoid sinuses result in a highly variable degree of extension, described in different ways in the literature. The aim of the study was to create the authors' classification of the sphenoid sinus extensions into the sphenoid bone processes.

Methods

The study was retrospective, based on the results of head CT scans. The study group comprised 432 children, aged from birth to 18 years. Three types of sphenoid sinus extension into the sphenoid bone processes were proposed. Pneumatization of the lesser wing (type I), of the greater wing (type II), and of the pterygoid process (type III). Three subtypes were defined for each type. Pneumatization of the lesser wing in relation to the optic canal: only above (Ia), only below (Ib), and simultaneously above and below (Ic). Pneumatization of the greater wing in relation to the foramen rotundum: only above (IIa), only below (IIb), and simultaneously above and below (IIc). Pneumatization of the pterygoid process in relation to the pterygoid canal: only laterally (IIIa), only medially (IIIb), and simultaneously laterally and medially (IIIc).

Results

Pneumatization of the lesser wings was observed in 19.44%, of the greater wings in 36.11%, and of the pterygoid processes in 25.00 of % children. As a result of the analysis conducted in accordance with the proposed classification, bilateral pneumatization of the lesser wings (type I), greater wings (type II), and pterygoid processes (type III) were found to occur more frequently than unilateral pneumatization. In the case of rare subtypes (Ia, Ic, IIa, Iic, or IIIb), a given subtype was observed to occur more frequently unilaterally.

Conclusions

In the conducted analysis, we presented the authors' classification of sphenoid sinus extensions into the sphenoid bone processes.