title: Implication of bony cochlear nerve canal on hearing in patients with congenital unilateral sensorineural hearing loss.
abstract: This study was designed to evaluate the dimensions of the bony cochlear nerve canal (BCNC) in congenital unilateral sensorineural hearing loss (USNHL) patients with normal inner ears, and to analyze the correlation between BCNC and hearing status. Medical records and temporal bone computed tomography (TBCT) findings of 380 patients who visited Seoul National University Hospital between January 1999 and December 2007 were reviewed retrospectively. The length and width of the BCNC at the fundus of the internal auditory canal were measured in millimeters based on the axial view of TBCT for three ear groups: normal inner ears of control group subjects (group A, 179 ears), normal inner ears on the contralateral side of USNHL patients (group B, 201 ears), and the affected inner ears in USNHL (group C, 201 ears). The mean values of length and width in group C (0.79 ± 0.36 and 1.58 ± 0.83 mm, respectively) were significantly smaller than those in group A (1.07 ± 0.10 and 2.38 ± 0.28 mm, respectively; p < 0.001) and group B (1.04 ± 0.23 and 2.33 ± 0.39 mm, respectively; p < 0.001). The receiver operating characteristic curves for BCNC were conducted to estimate the cutoff values from which the proportions of profound hearing loss increased, compared to those of mild to severe hearing loss. The areas under the curve were 0.487 ± 0.044 (p = 0.781) and 0.622 ± 0.041 (p = 0.011) for length and width, respectively. The cutoff value of width with a sensitivity of 90% for profound USNHL was 1.16 mm in otherwise normal inner ears. Clinicians would be recommended to take a close look at BCNC as one of the possible causes of hearing loss in otherwise normal inner ears of USNHL on TBCT.
authors.affiliation: Department of Otorhinolaryngology, Kyungpook National University College of Medicine, Daegu, Republic of Korea.
authors.forename: Jeong Hun
authors.initials: JH
authors.lastname: Jang
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Jae Chul
authors.initials: JC
authors.lastname: Yoo
authors.forename: Chang-Hee
authors.initials: CH
authors.lastname: Kim
authors.forename: Min Soo
authors.initials: MS
authors.lastname: Kim
authors.forename: Sun O
authors.initials: SO
authors.lastname: Chang
authors.forename: Seung Ha
authors.initials: SH
authors.lastname: Oh
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
mesh_terms: D002648:Child; D003056:Cochlear Nerve / Q000002:abnormalities* / Q000000981:diagnostic imaging; D007758:Ear, Inner / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology; D046088:Hearing Loss, Unilateral / Q000151:congenital / Q000000981:diagnostic imaging / Q000209:etiology; D006801:Humans; D008297:Male; D015588:Observer Variation; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013701:Temporal Bone / Q000002:abnormalities* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data; D000160:Vestibulocochlear Nerve Diseases / Q000151:congenital / Q000000981:diagnostic imaging* / Q000209:etiology