Lateral semicircular canal dilatation in a patient with congenital hearing loss due to α-tectorin mutation: microanatomical considerations.

The tectorial membrane is crucial in the physiology of the auditory neuroepithelium. Mutations in one of its functional molecules, α-tectorin, lead to autosomal dominant and recessive congenital mid-frequency, non-syndromic hearing loss.Typically, α-tectorin mutations are not accompanied by any morphological abnormalities of the labyrinth. For the first time, we present a case of a toddler boy with congenital hearing loss due to TECTA gene mutation and concomitant bilateral dilation of the lateral semicircular canals.The expression of glycoproteins, like α-tectorin, varies between the distinct labyrinth acellular membranes. Various mutations in the TECTA gene may affect additional glycoproteins that share a high percentage of sequence similarity at the amino acid level with α-tectorin. The mutated glycoproteins differ in the hydration level of their side chains of glycosaminoglycans. Hydration level could affect the mass of the ampullary cupula of the lateral semicircular canal leading to its dilation during embryogenesis.

The Eustachian Tube Dysfunction in Children: Anatomical Considerations and Current Trends in Invasive Therapeutic Approaches.

The eustachian tube (ET) has a crucial role in the physiology of the middle ear. Thus, any condition that renders the tube dysfunctional is directly implicated with middle ear pathophysiology, like in the case of acute otitis media and otitis media with effusion. Children are more vulnerable to pathologies of the middle ear, primarily due to the immature development of their eustachian tubes. Otitis media with effusion, apart from being a burden for hearing, with direct consequences for speech development, may also be implicated in cholesteatoma formation. Medical therapy is not practically effective for the treatment of effusion. Moreover, the established surgical approaches, like grommets and adenoidectomy, deal only indirectly with the problem since they are not addressing the dysfunctional ET itself. An emerging interventional approach that intends to restore the function of the tube is the transnasal balloon dilation of the cartilaginous part of the ET. Growing international experience indicates that this promising technique is safe and effective. In the current review, we aim to provide background information on the anatomy, physiology, and pathophysiology of the ET and to present the progress of the balloon dilation technique with emphasis on pediatric patients.