Genetics of Inner Ear Malformations: A Review

Inner ear malformations are present in 20% of patients with sensorineural hearing loss. Although the first descriptions date to the 18th century, in recent years the knowledge about these conditions has experienced terrific improvement. Currently, most of these conditions have a rehabilitative option. Much less is known about the etiology of these anomalies. In particular, the evolution of genetics has provided new data about the possible relationship between inner ear malformations and genetic anomalies. In addition, in syndromic condition, the well-known presence of sensorineural hearing loss can now be attributed to the presence of an inner ear anomaly. In some cases, the presence of these abnormalities should be considered as a characteristic feature of the syndrome. The present paper aims to summarize the available knowledge about the possible relationships between inner ear malformations and genetic mutations.

Sequential Bilateral Cochlear Implantation in a Child with Severe External, Middle, and Inner Ear Malformations: Surgical Considerations and Practical Aspects

Cochlear implantation (CI) is a safe and beneficial surgery for children with congenital inner ear malformations, with the exception of cochlear nerve aplasia. The combination of microtia with middle and inner ear abnormalities is extremely uncommon and sufficiently severe to make a surgical approach to the cochlea difficult. We report herein the case of a 2-year-old girl who presented with profound bilateral sensorineural hearing loss, congenital aural atresia, microtia, and inner ear malformations. High-resolution computed tomography revealed poor development of the bilateral middle ear spaces, absence of the incus and stapes, aberrant courses of facial nerves, aplastic lateral semicircular canals, and covered round windows. With intraoperative imaging assistance, sequential bilateral CI was performed using a transmastoid approach with no complication. We propose that CI is feasible in patients with severe external and middle ear malformations. However, major malformations increase the risk of complications. As the facial nerve and cochlea are difficult to locate due to the lack of important anatomical landmarks, detailed planning and adequate preparation, including review of the preoperative imaging data, and the use of facial nerve monitoring and intraoperative imaging are very important. In addition, experienced surgeons should perform CI to ensure the success of the operation.

Imaging of inner ear malformations: a primer for radiologists

In the multidisciplinary management of patients with inner ear malformations (IEMs), the correct diagnosis makes the differences in terms of clinical and surgical treatment. The complex anatomical landscape of the inner ear, comprising several small structures, makes imaging of this region particularly challenging for general radiologists. Imaging techniques are important for identifying the presence and defining the type of IEM and the cochlear nerve condition. High-resolution magnetic resonance imaging (MRI) sequences and high-resolution computed tomography (HRCT) are the mainstay imaging techniques in this area. Dedicated MRI and HRCT protocols play an important role in the diagnosis and treatment of patients with inner ear disease. The most suitable technique should be selected depending on the clinical setting. However, in cases of congenital malformation of the inner ear, these techniques should be considered complementary. Since prompt intervention has a positive impact on the treatment outcomes, early diagnosis of IEMs is very important in the management of deaf patients. This article reviews the key concepts of IEMs for clinical radiologists by focusing on recent literature updates, discusses the principal imaging findings and clinical implications for every IEM subgroup, thus providing a practical diagnostic approach.