Endonasal Anterior Skull Base: Variability of the Bony Anatomy and Gender-Related Differences in Adults

The endoscopic endonasal approaches (EEAs) to the anterior skull base (ASB) are used with increased frequency. We present the results of the morphometric analysis of the endonasal anterior skull base bony anatomy in adults. A total of 103 adult patients with computed tomography (CT) scan of the face were included. Exclusion criteria included patients who were <18 years of age or radiographic evidence of neoplasm, infection, previous surgery, or trauma. The images were analyzed using OsiriX MD. We collected the patients' demographics and measured the ASB length and angle in the midsagittal plane. Also, we measured the width, the angle of the ethmoid, and the height of the piriform aperture. Wilcoxon's rank-sum test was used for data analysis with a significance level of p < 0.05. The average age was 44.9 with 47% males. The mean ASB length and angle were 48.7 mm (SD ± 3.8) and 34.3 degrees (SD ± 2.9), respectively. The ethmoidal width and coronal angles were 23.9 mm (SD ± 2.9) and 27.2 degrees (SD ± 3.1) respectively. The piriform height was 32.1 mm (SD ± 4.4; [Fig. 1]). Females had a shorter ASB (47.1 vs. 50.2 mm, p < 0.05), a wider angle (35.1 vs. 33.7 degrees, p < 0.05), and a shorter piriform height (30.6 vs. 33.4 mm, p < 0.05). Also, females had a narrower ethmoid (23.1 vs. 24.6 mm, p < 0.05; [Fig. 2]). There are significant variability and gender-related differences in the bony anatomy of the endonasal anterior skull base in adults. These differences can affect the dimensions and freedom of movement of the endoscopic endonasal approaches to the anterior skull base.

Fig. 1

Fig. 2

Publication History

Article published online:
12 February 2021