Inner-ear malformations as a cause of single-sided deafness

Abstract

<jats:title>Abstract</jats:title><jats:sec id="S0022215120001036_sec_a1" sec-type="other"><jats:title>Objective</jats:title><jats:p>To determine the prevalence and distribution of inner-ear malformations in congenital single-sided deafness cases, as details of malformation type are crucial for disease prognosis and management.</jats:p></jats:sec><jats:sec id="S0022215120001036_sec_a2" sec-type="methods"><jats:title>Methods</jats:title><jats:p>A retrospective study was conducted of 90 patients aged under 16 years with congenital single-sided deafness. Radiological findings were evaluated using computed tomography and magnetic resonance imaging. Inner-ear malformations were identified and cochlear nerve status was determined in affected ears.</jats:p></jats:sec><jats:sec id="S0022215120001036_sec_a3" sec-type="results"><jats:title>Results</jats:title><jats:p>Out of 90 ears, 42 (46.7 per cent) were found to have inner-ear malformation. Isolated cochlear aperture stenosis was the most common anomaly (<jats:italic>n</jats:italic> = 18, 20 per cent), followed by isolated cochlear aperture atresia (<jats:italic>n</jats:italic> = 11, 12.2 per cent) and cochlear hypoplasia (<jats:italic>n</jats:italic> = 7, 7.8 per cent). Cochlear nerve deficiency was encountered in 41 ears (45.6 per cent). The internal auditory canal was also stenotic in 49 ears (54.4 per cent).</jats:p></jats:sec><jats:sec id="S0022215120001036_sec_a4" sec-type="conclusions"><jats:title>Conclusion</jats:title><jats:p>Inner-ear malformations, especially cochlear aperture anomalies, are involved in the aetiology of single-sided deafness more than expected. The cause of single-sided deafness differs greatly between congenital and adult-onset cases. All children with single-sided deafness should undergo radiological evaluation, as the prognosis and management, as well as the aetiology, may be significantly influenced by inner-ear malformation type.</jats:p></jats:sec>

Cochlear Nerve Deficiency in Pediatric Unilateral Hearing Loss and Asymmetric Hearing Loss

“…CND was demonstrated in 29.9% of ears in the UHL population, which is within the reported range in the literature. However, this is slightly below the median previously reported in the literature, with 5 of the 8 cited studies reporting nerve deficiency in 39-50% of ears [Clemmens et al, 2013;Nakano et al, 2013;Paul et al, 2017;Usami et al, 2017;van Beeck Calkoen et al, 2017;Lipschitz et al, 2020;Pollaers et al, 2020;Tahir et al, 2020]. In contrast to the UHL cohort, CND was found in a significantly lower proportion of ears in the AHL population (11.5%).…”

“…While several past studies have evaluated CND in pediatric patients with UHL, the literature has reported widely variable prevalence of CND ranging from 9 to 50% [Clemmens et al, 2013;Nakano et al, 2013;Paul et al, 2017;Usami et al, 2017;van Beeck Calkoen et al, 2017;Lipschitz et al, 2020;Pollaers et al, 2020;Tahir et al, 2020]. Evaluation of CND in pediatric patients with AHL has been limited in the literature, with studies reporting a range of 0-28% prevalence of CND [Usami et al, 2017;Lipschitz et al, 2020].…”

Do Otologists and Other Otolaryngologists Manage Single-Sided Deafness Differently?

“…However, Zhan et al 28 reported that MRI imaging was their first choice in children, and if MRI findings were not optimal, they used temporal bone CT as an adjunct. Tahir et al 32 reported that they generally preferred CT + MRI together as imaging for children with a diagnosis of SSD but recently stated that to reduce radiation exposure, they prefer only MRI for children for whom surgery is not considered. 32 While CT is useful for the diagnosis of middle and inner ear anomalies (partition anomalies and common cavity), MRI is a standard diagnostic tool to detect the absence of the cochlear nerve.…”

“…Tahir et al 32 reported that they generally preferred CT + MRI together as imaging for children with a diagnosis of SSD but recently stated that to reduce radiation exposure, they prefer only MRI for children for whom surgery is not considered. 32 While CT is useful for the diagnosis of middle and inner ear anomalies (partition anomalies and common cavity), MRI is a standard diagnostic tool to detect the absence of the cochlear nerve. Therefore, Park et al 33 recommend high-resolution 3-dimensional MRI imaging.…”

Congenital Unilateral Hearing Loss: Characteristics and Etiological Analysis in 121 Patients

“…A cochlear nerve deficiency was the most frequent MRI finding. We prefer to use this term because the difference between hypoplasia and aplasia is not always evident, and cochlear aperture width and cochlear nerve status do not always correlate (24). Cochlear nerve deficiency has been found in about 30% of the patients with congenital sensorineural hearing loss and accounts for even a higher percentage in the group of severe to profound hearing loss (13,25).…”