Cochlear implant surgery in challenging cases

Abstract

Expanding selection criteria and increasing numbers of cochlear implantations have revealed several challenging cases with regard to surgery and medical point of view. Cochlear implantation of congenitally deaf children with inner-ear malformations may involve difficulties in preoperative evaluation, surgical approach and postoperative follow-up. Cochlear nerve aplasia (as evidence of only one existing nerve in three dimensional magnetic resonance imaging) and hypoplastic cochleas are among the most difficult cases and sometimes children are considered unsuitable for cochlear implantation. However, there is always the possibility that hypoplastic cochleas may include ganglion cells and the only nerve in the internal auditory canal (facial nerve) may contain auditory fibres as well. A positive history of auditory experience and evidence of electrical auditory brainstem response or response to the promontory or round window electrical stimulation may imply that a functioning auditory system is in place. Malformations like common cavity deformity, isolated bilateral vestibular aqueduct enlargement and Mondini dysplasia are usually less challenging, although cerebrospinal fluid leak and postoperative meningitis may be a possibility. In cases of post-meningitic deaf patients, ossification (or obliteration) may be a serious problem even if computed tomography and MRI scan show a patent cochlea or minimal changes. Acoustic neuromas and neurofibromatosis type 2 are other challenging cases, as there is always the possibility that the sensorineural hearing loss is secondary to cochlear damage by interference of the tumour to cochlear blood supply. In conclusion, challenging cases are becoming more common as we are expanding selection criteria, and we should be prepared for alternative cochlear implant devices (straight electrode arrays, dual arrays, compressed arrays, etc.), increased rate of possible complications at, and following, surgery, and functional outcome that may vary considerably among implantees.

Bilateral implantation in children with cochleovestibular nerve hypoplasia

“…Expanding selection criteria and increasing numbers of cochlear implantations have revealed several challenging cases with regard to surgical and medical perspectives. Cochlear implantation of congenitally deaf children with inner ear malformations may involve difficulties in preoperative evaluation, surgical approach and postoperative followup [8,9]. Hypoplastic cochleovestibular nerve remains among the most difficult cases [10].…”

Characteristic of hearing loss in children with Pendred syndrome and results of its treatment with cochlear implants – a literature review

“…Pomimo charakterystycznych cech budowy ucha wewnętrznego proces implantacji ślimakowej u pacjentów z zespołem Pendreda nie wiąże się z wyższym niż zazwyczaj odsetkiem komplikacji śródoperacyjnych [30]. Do najczęściej wymienianych należy wyciek perylimfy lub płynu mózgowo-rdzeniowego spotykany głównie podczas kochleostomii [30,[34][35][36][37]. W zależności od ośrodka, liczby analizowanych przypadków i przyjętej metodologii częstość występowania tego powikłania waha się istotnie pomiędzy poszczególnymi badaniami od 14,5 do 80% pacjentów [21,30,35,37].…”

“…Chociaż autorzy analizowanych prac podają, że w niektórych przypadkach wymienione komplikacje śródoperacyjne, a także charakterystyczna budowa ucha wewnętrznego pacjentów z zespołem Pendreda, mogą być przyczyną pooperacyjnego zapalenia opon mózgowo-rdzeniowych, to teza ta nie znajduje jednoznacznego potwierdzenia w piśmiennictwie [34,40,42,44]. W celu uniknięcia Now Audiofonol, 2019; 8(2): 20-25 tego powikłania zaleca się profilaktyczną aplikację antybiotyków zgodnie z antybiogramem oraz przedoperacyjne szczepienie przeciwko S. pneumoniae [21,30,35,36].…”

Prognostic indicators in paediatric cochlear implant surgery: a systematic literature review

“…Children are being implanted in early infancy, the surgery is now applied to growing numbers of children with less severe hearing losses and bilateral implantation is increasing (Kirk et al, 2000;Nikolopoulos and Kiprouli, 2004;Loudon et al, 2005;Dettman et al, 2004a, b;ASHA, 2004). Universal neonatal screening, in particular, has contributed to earlier recognition of sensorineural hearing loss (SNHL) by identifying many profoundly deaf infants at birth (James, 2004;Bauer et al, 2003).…”