Congenital malformations of the ear and cochlear implantation in children: review and temporal bone report of common cavity

Abstract

The objective of this review is to analyze aspects of congenital malformation of the ear in relation to cochlear implantation in children. Having briefly described the in utero development of the ear and the classification of types of external, middle and inner ear malformation, five practical aspects of these malformations are discussed. It seems likely that the combination of bilateral profound sensorineural deafness with bilateral microtia severe enough to make a surgical approach to the cochlea difficult will be extremely uncommon. No such cases have been reported, although Klippel-Feil deformity seems the syndrome most likely to produce this set of circumstances.Abnormalities in the intratympanic course of the facial nerve have been associated with cochlear malformation, emphasizing the benefit of intra-operative facial nerve monitoring, and a technique suggested for safely avoiding an abnormally placed nerve. Fistulae of cerebrospinal fluid (CSF) and perilymph can complicate surgery and are relatively common in common cavity and Mondini malformations. Strategies for facilitating surgery in the presence of ‘gushers’, for measuring the pressure of a gusher and for placement of the cochlear implant electrode array are reviewed, with reports of fluctuating levels of electric current when implants lie in dysplastic cochleas.The relationship of implant performance to VIIIth nerve tissue in malformed cochleas is discussed, with a description of the histological findings in a common cavity cochlea. Techniques for identifying the absence of the cochlear nerve are reviewed. Stimulation of the facial nerve by cochlear implants has been described in cases of congenital malformation of the labyrinth but is relatively uncommon. Case reports of the benefit received by implanted children with congenital cochlear malformation have appeared since 1988. Most cases reported have not yet been followed for long enough to establish a clear picture of the outcome following cochlear implantationin such children; no centre has yet built up a large series of cases, but there have been two multicentre postal surveys. It seems likely that in cochlear malformation the range of potential outcomes in terms of hearing threshold and the development of speech perception and production will be similar to the range found in implanted children without cochlear dysplasia. However there is, as yet, no clear picture of the mean level of performance within this range.

Benign paroxysmal vertigo of childhood: A review of the literature

“…The subjective interview should include a profile of development, including any anatomical or developmental anomalies or congenital abnormalities (1,46,47). A history of 'TORCH' (toxoplasmosis, other infections, rubella, cytomegalovirus infection and herpes simplex) infections are often associated with labyrinthitis (6,47), cardiorespiratory disease and head trauma, and a family history of vertigo, Batson migraine, hearing loss, demyelinating disease or seizures (6,47).…”

Cochlear Implants in Forty-Eight Children with Cochlear and/or Vestibular Abnormality

“…While successful surgery and good insertion depth are important, they do not guarantee development of speech perception and subsequent language development [Dowell et al, 2002a]. Some studies have examined the relationship between degree of cochlear abnormality and speech perception outcomes [Eisenman et al, 2001;Papsin, 2005] but not language outcomes, and there has been no examination of the relative effects of other known variables (such as duration of profound loss, communication mode, onset and course/progression of hearing loss and cognitive status) [Graham et al, 2000]. It is important to understand the efficacy of cochlear implants for the population of children with cochlear and/or vestibular abnormality compared to the normal population.…”

Effects of gestational exposure to ethane dimethanesulfonate in CD‐1 mice: Microtia and preliminary hearing tests

“…Severe cases of microtia have previously been correlated with dysplasia of the middle ear, potentially due to the common embryonic origin of the two structures (Kountakis et al, 1995;Calzolari et al, 1999;Graham . Average BAER waveforms for adult animals gestationally exposed to vehicle or 160 mg/kg/day EDS after stimulation with a rarefaction click, 4, 16, or 64 kHz tone pips.…”