Hypoplasia off the bony canal for the cochlear nerve in patients with congenital sensorineural hearing loss: Initial observations

PURPOSE: To evaluate the length and width of the bony canal of the cochlear nerve in patients with congenital sensorineural hearing loss (SNHL) who ha ve "normal" findings at thin-section computed tomography (CT) of the tempor al bone. MATERIALS AND METHODS: The authors retrospectively evaluated the length and width of the bony canal for the cochlear nerve in two groups of patients. The first group was composed of 33 patients with profound SNHL and no demon strable abnormality at thin-section CT. The control group was composed of 5 0 patients who underwent temporal bone CT for causes unrelated to SNHL. The mean value +/- SD was calculated for both cohorts. Statistical analysis co nsisted of the nonparametric Wilcoxon rank sum test with the NPAR1WAY progr am. RESULTS: The length and width of the bony canal for the cochlear nerve were significantly smaller in patients with SNHL than in the control group (P < .05) CONCLUSION: The hypoplastic bony canal for the cochlear nerve in patients w ith SNHL may be indicative of a previously unrecognized embryologic malform ation of the cochlear nerve.