Cochlear implantation in the congenitally malformed ear

Abstract

Approximately 20%-35% of patients with profound congenital sensorineural hearing loss have radiographic evidence of anatomic inner ear abnormalities. 1 Jackler R.K. Luxford W.M. House W.F. Congenital malformations of the inner ear: A classification based on embryogenesis. Laryngoscope. 1987; 97: 2-14 Crossref PubMed Scopus (622) Google Scholar , 2 Parry D.A. Booth T. Roland P.S. Advantages of magnetic resonance imaging over computed tomography in preoperative evaluation of pediatric cochlear implant candidates. Otol Neurotol. 2005; 26: 976-982 Crossref PubMed Scopus (114) Google Scholar , 3 McClay J.E. Tandy R. Grundfast K. et al. Major and minor temporal bone abnormalities in children with and without congenital sensorineural hearing loss. Arch Otolaryngol Head Neck Surg. 2002; 128: 664-671 Crossref PubMed Scopus (92) Google Scholar , 4 Papsin B.C. Cochlear implantation in children with anomalous cochleovestibular anatomy. Laryngoscope. 2005; 115: 1-26 Crossref PubMed Scopus (262) Google Scholar In the past, congenital malformations of the inner ear were considered by some to be a contraindication to cochlear implantation due to surgical concerns over electrode placement as well as expected poor audiologic performance. 5 Phelps P.D. Cochlear implants for congenital deformities. Jour Laryn Oto. 1992; 106: 967-970 Crossref Scopus (38) Google Scholar With the advent of improved imaging modalities as well as refined surgical techniques, implantation of the malformed inner ear is now performed frequently. In addition, recent studies continue to demonstrate a significant hearing benefit from cochlear implants in patients with inner ear dysplasia. 6 Buchman C.A. Copeland B.J. Yu K.K. et al. Cochlear implantation in children with congenital inner ear malformations. Laryngoscope. 2004; 114: 309-316 Crossref PubMed Scopus (117) Google Scholar , 7 Hoffman R.A. Downey L.L. Waltzman S.B. et al. Cochlear implantation in children with cochlear malformations. Am J Otol. 1997; 18: 184-187 PubMed Google Scholar These hearing results, however, tend to correlate with the severity of the inner ear malformation.