Presence and types of anterior clinoid process pneumatization, evaluated by Multidetector Computerized Tomography.

PURPOSE The types and ratio of anterior clinoid process (ACP) pneumatization in paranasal sinus Multidetector Computerized Tomography (MDCT) were investigated the importance of ACP in neurosurgical approaches discussed. METHODS Paranasal MDCT images of 499 subjects (259 male, 240 female), between 17 and 65 years of age, were included in the study. Presence and types of pneumatization of the ACP and pneumatization types (I, II or III) were evaluated. RESULTS ACP pneumatization was detected in 37.5% of the males and 33.3% of the females. Right, left and bilateral ACP pneumatizations were detected in 12.7%, 9.3% and 15.4% of males and 9.2%, 8.3% and 15.8% of the females, respectively. The most commonly detected types of pneumatization were Type I (49.1%) for right pneumatizations and Type II pneumatization for left (40.9%) and bilateral (37.2%) pneumatizations. In males, Type I (37.1%) and in females, Type II (40.0%) pneumatizations were detected more frequently. Type III pneumatization was detected in 29.9% of the males and 22.5% of the females. ACP pneumatization ratios were higher in younger subjects and lower in older subjects. CONCLUSION Sclerosis process related to aging may be responsible for the lower pneumatization ratios in older subjects. When Type III ACP pneumatization is present, clinoidectomy should not be performed: in this type of ACP pneumatization, cerebrospinal fluid fistula develops in all cases.