Epidemiologic, Imaging, Audiologic, Clinical, Surgical, and Prognostic Issues in Common Cavity Deformity

Abstract

IMPORTANCECommon cavity deformity is a rare congenital inner ear malformation associated with profound hearing loss and attributed to an early developmental arrest of the cochlear-vestibular structures. This narrative review highlights the need to identify reliable indicators of hearing rehabilitation outcome.OBSERVATIONS Despite its relatively simple definition, common cavity deformity varies widely in morphologic features, presence of cochlear nerve fibers and remnants of Corti organ, and outcome after cochlear or brainstem implant. CONCLUSIONS AND RELEVANCECochlear implant has been shown to be a valid option for common cavity deformity, but its outcome remains variable and poor. Identification of specific neuroradiologic, audiologic, and neurophysiologic prognostic features; tailoring of the surgical approach; and standardization of outcome measures are needed to optimize the management of common cavity deformity and hearing rehabilitation after implant.

Evaluating Common Cavity Cochlear Deformities Using CT Images and 3D Reconstruction

“…Although MRI is the gold standard for the identification of the cochlear nerve (CN), 22 it is discussed to be prone to errors 8 . The absence of a clearly visible CN is not appropriately distinguishing between CC and CA because CA may present with a hypoplastic nerve, and CC usually is associated with a common cochleovestibular nerve (CVN) 12,23 . Batuk et al report a case series of 12 children who received auditory brainstem implant after poor hearing outcomes with CI alone.…”

“…Different radiological phenotypes are being discussed. The size of the CC varies in previous studies and the limit to other malformations such as incomplete partition type 1 (IP‐1) is not clearly defined 12 …”

Genetics of Inner Ear Malformations: A Review

“…The common cavity is characterized by the absence of the normal differentiation between the cochlea and vestibule with the result of a single cystic cavity (see Figure 1). Common cavity is supposed to be the result of a developmental arrest in the fourth week of gestation and accounts for about 0.7-26% of cochlear malformations [7].…”

“…Common cavities are assumed to have a non-genetic origin. However, two studies might suggest otherwise: one study found an association between common cavity deformity and autosomal recessive truncating HOXA1(P49639) mutations in an Bosley-Salih-Alorainy syndrome variant [22], another study described the case of a family with two Common cavity is supposed to be the result of a developmental arrest in the fourth week of gestation and accounts for about 0.7-26% of cochlear malformations [7].…”

“…For the most severe malformations (such as Michel deformity or cochlear aplasia), a brainstem implant is now considered an available option [4,5], while for most of the other malformations, rehabilitation can be performed with hearing aids until a feasible cochlear implantation is available [6]. In some cases (i.e., common cavity deformities), it is still debated which procedure can offer the best results in terms of auditory outcome, but multiple options are available [7].…”