Relation between the Internal Acoustic Canal and the Volume of Petrous Apex and Translabyrinthine Corridors in Adults

The internal acoustic canal (IAC) and jugular foramen (JF) are important landmarks when performing anterior or posterior petrosectomy approaches. We present the analysis of the anatomic variability of the IAC angle and the distance between the IAC and JF in adults. Also, we describe the correlation between the IAC angle and IAC–JF distance and the volume of the petrous apex (PA) and translabyrinthine (TL) corridors. Seventy-six computed tomography scans of the head were selected. Exclusion criteria included patients <18 years of age, radiographic evidence of trauma, neoplasm, infection, or previous surgery. The images were analyzed using OsiriX MD (Bernex, Switzerland). We measured the IAC angle, IAC–JF distance, and the volume of the PA and TL corridors using three-dimensional reconstruction. The average age was 49 years with 44% females. The mean IAC angle and IAC–JF distances were 79.8 degrees and 15.2 mm, respectively. The mean PA and TL volume was 2.2 and 10.1 cm³, respectively. The IAC angle correlated negatively with both the PA volume (rho = −0.4, p < 0.05) and TL volume (rho = −0.3, p < 0.05), and the IAC–JF distance correlated positively with both the PA volume (rho = 0.3, p < 0.05) and TL volume (rho = 0.4, p < 0.05; [Fig. 1]). The petrous apex and translabyrinthine corridors are among the most commonly used skull base approaches. Our analysis showed that a longer distance between the IAC and the JF leads to a larger PA and TL corridors, while a wider IAC angle leads to a smaller PA and TL corridors. Also, we found significant variability in the dimensions of the IAC angle and IAC–JF distance among adults ([Figs. 2]–[4]).

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Artikel online veröffentlicht:
12. Februar 2021