Abstract

Objectives: To systematize the anatomical study of the vestibular aqueduct using high resolution computed tomography (HRCT) and to evaluate the retrolabyrinthine region in patients with unilateral Ménière’s disease (MD).

Methods: The vestibular aqueduct is one of the most studied labyrinth structures in the genesis of endolymphatic hydrops and has a possible anatomic and physiological role in this disease. Twenty patients with unilateral Ménière’s disease and ten normal patients (control group) underwent HRCT of temporal bones. In total 60 ears were analyzed, 20 of them in each of the following groups: GI (ear affected by MD), GII (MD group - ear not affected), GIII (control). The images were analyzed blindly. The vestibular aqueduct was identified and the measurements were acquired in its middle portion and in the external opening. The retrolabyrinth dimension was also measured in these patients. These findings were analyzed and compared between these groups.

Results: The vestibular aqueduct was identified in the ears of 95% of GI, 90% of G II and 100% of G III, and measurements of the width of the middle portion and external opening of vestibular aqueduct were analyzed and showed no statistical difference between the three groups. The retrolabyrinthine dimension was similar between groups G I and G II, but significantly higher in G III (G I=G II<G III).

Conclusion: It is possible to apply the proposed systematization for the evaluation of the vestibular aqueduct by HRCT. The identification and measurement of vestibular aqueduct width did not show statistically significant differences between affected (GI) and unaffected (GII) ears of patients with Ménière’s disease, nor in relation to the control group (GIII). The retrolabyrinthine dimension was significantly higher in the control group (GIII) compared to that of GI and GII

Keywords: Vestibular aqueduct; Temporal bone; Meniere’s disease; Retrolabyrinthine dimension; High resolution computed tomography ; Endolymphatic hydrops; Ear