Presence of vascular loops entering internal acoustic channel may increase risk of Sudden sensorineural hearing loss and reduce recovery of these patients.

Abstract

To analyze whether there is correlation between branching patterns of anterior inferior cerebellar artery/posterior inferior cerebellar artery (AICA/PICA) in cerebellopontine angle (CPA) area, as demonstrated by three-dimensional fast imaging employing steady-state acquisition (3D FIESTA) magnetic resonance imaging (MRI) and 1) idiopathic sudden sensorineural hearing loss (ISSNHL) outcomes and 2) recovery of ISSNHL. We evaluated patients with idiopathic SSNHL for branching patterns of AICA/PICA in CPA area, as demonstrated by 3D FIESTA MRI. Sixty-eight patients with SSNHL (32 [47.1%] women; mean age 45.3 ± 14.6 [minimum-maximum: 18-77]) and 38 healthy volunteers [17 (44.7%) women; mean age 48.6 ± 14.0 (minimum-maximum: 26-81)] were included in this study. We evaluated patients for branching patterns and classified as type IA, IB, IIA, and IIB. Branching patterns were evaluated at the diseased side of the patients and both sides of the control group. Pretreatment and posttreatment audiological values were also studied. AICA/PICA branching patterns in control group versus study group in the affected side were: 26 (34.2%) versus 12 (17.6%) subjects had type IA; seven (9.2%) versus nine (13.2%) subjects had type IB; 31 (40.8%) versus 23 (33.8%) subjects had type IIA; and 12 (15.8) versus 24 (35.3%) subjects had type IIB branching patterns, respectively. Presence of vascular loops entering internal acoustic channel (type IIB branching pattern) was more prominent in the study group (P = 0.017). In addition, type IIB branching pattern was significantly associated with unresponsiveness to treatment (18 [75%] of 24 patients with type IIB were unresponsive and 14 [47.0%] of 30 patients with nontype IIB were unresponsive, P < 0.001). Type IIB branching pattern has been shown to be more common in patients with ISSNHL, and these patients come across with unresponsiveness to standard therapy more than the other branching types. 3b. Laryngoscope, 127:210-215, 2017.