The pneumatization of the sphenoid sinus, its variations and relations with surrounding neurovascular anatomic structures: A computerized tomography study.

ABSTRACT

INTRODUCTION AND OBJECTIVES: The wide range of variability of SS pneumatization and relation with surrounding structures can result in serious complications; seeing that, the assessment of regional anatomy is essential for both surgeons and radiologists. We mainly aim to reveal the possible correlation between the SS pneumatization types and protrusion/dehiscence of the adjacent neurovascular structures in a larger population by using computerized tomography (CT) images. METHODS: The type of SS pneumatization (I-IV), pneumatization of anterior clinoid process (ACP), greater wing of sphenoid (GWS), and pterygoid process (PP) was evaluated. Protrusion and dehiscence of ICA, ON, MN, and VN was noted. RESULTS: 1003 patients were included into the study. ICA, ON, and MN protrusions were not seen in patients with the type I or II SS on both sides. These protrusions were most frequently seen along with the type IV SS on both sides (p < 0.05). ICA, ON, MN, and VN dehiscence was not found in any patients with the type I SS. The rate of ICA protrusion increased with presence of GWS and PP; ICA dehiscence was found to be positively correlated with ACP, GWS, and PP pneumatization. CONCLUSIONS: Variations, either amount or the extent, of the pneumatization of the SS are related with the presence of protrusion/dehiscence of ICA, ON, MN and VN. Knowing and reporting these relations can decrease the rate of complications during skull base surgery.