Role of resection of torus tubarius to maximize the endonasal exposure of the inferior petrous apex and petroclival area

Abstract

Endoscopic access to the petrous apex and petroclival region often requires sacrificing the Eustachian tube (ET). This study aimed to compare the maximum exposure of the petrous apex and petroclival region via an endonasal corridor when sparing or resecting the ET and its torus. Six cadaveric specimens (12 sides) were dissected through an endonasal transpterygoid approach. Endonasal exposure of the petroclival region was completed using techniques that included the preservation of the ET (group 1), resection of the torus tubarius (group 2), and resection of the ET (group 3) were sequentially performed on each side. The working distances from the anterior genu of the petrous internal carotid artery (ICA) to the inferior boundaries of each corridor were measured and compared. In group 1, the medial petrous apex and petroclival sulcus could be exposed with a working distance of 4.08 ± 0.67 mm. In group 2, the fossa of Rosenmüller, inferior petrous apex, and hypoglossal canal could be exposed, with a significantly increased working distance of 18.33 ± 0.89 mm (P = .001). In group 3, the exposure and ICA control was superior and offered a working distance of 20.67 ± 0.78 mm. No statistically significant difference derived from comparing groups 2 and 3 (P = .875). Resection of the torus tubarius can increase exposure of the petrous apex and petroclival region. It provides an alternative to resecting the ET, which might be beneficial for maintenance of middle ear function. ET resection, however, seems superior when ICA control is required.