The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2004 The American Laryngological, Rhinological and Otological Society, Inc. Cochlear Implantation in Children with Congenital Inner Ear Malformations Craig A. Buchman, MD; Benjamin J. Copeland, MD, PhD; Kathy K. Yu, MD; Carolyn J. Brown MS, CCC-SLP; Vincent N. Carrasco, MD; Harold C. Pillsbury, III, MD Objective/Hypothesis: To assess the audiologic and surgical outcomes for pediatric cochlear implant patients with inner ear malformations. Study Design: Retrospective review of 315 pediatric cochlear im- plant cases from 1994 to 2002. Methods: Twenty-eight pediatric cochlear implant patients with known inner ear malformations determined on high-resolution computed tomography (HRCT) of the temporal bone were the subjects of review. Results of HRCT findings, intraoperative findings, postoperative complications, and objective measures of both closed- and open-set testing of speech perception were analyzed. Results: Patients with the constellation of an incompletely partitioned (IP) cochlea, enlarged vestibular aque- duct (EVA), and a dilated vestibule (i.e., Mondini’s malformation) as well as those with an isolated EVA or partial semicircular canal aplasia have relatively good levels of speech perception. Patients with total semicircular canal aplasia, isolated IP, cochlear hyp- oplasia, or common cavity demonstrated lower levels of performance. Poor performance may be related to associated developmental delays rather than labyrin- thine anatomy alone. Complications of surgery were relatively limited. Conclusions: Cochlear implanta- tion can be successfully performed in children with inner ear malformations. These children and their parents can expect significant auditory benefits from this intervention. The various types of inner ear malformations may have quite different prog- noses for good auditory performance. Key Words: Cochlear implant, malformation, Mondini, perfor- mance, laryngoscope. Laryngoscope, 114:309 –316, 2004 INTRODUCTION The evaluation and management of children with profound hearing loss (HL) and associated inner ear de- velopmental malformations present a significant chal- lenge to even the most experienced clinician. In fact, until recently, many cochlear implant centers deferred implan- tation in these children because of uncertainty regarding surgical feasibility and performance expectations. Many reports have focused on the surgical details of implanting the malformed inner ear, with little attention being given to the audiologic outcomes. 1–9 Others that include audio- logic information have been largely descriptive, with only few giving hard data 10 –15 or specific speech perception results. 16 –22 Moreover, the relative rarity of the various inner ear malformations has precluded a large accumula- tion of patients at one center; thus, little is truly known about the differences among the specific types of inner ear malformations. The purpose of the current study was to detail the experience of a single, large pediatric cochlear implant center with an emphasis on reporting objective outcome measures on the various types of inner ear malformations. MATERIALS AND METHODS This study is part of an ongoing, retrospective case review of 315 children with cochlear implants in the W. Paul Biggers, MD, Carolina Children’s Communication Disorders Program (CCCDP), Department of Otolaryngology–Head and Neck Surgery, at the Uni- versity of North Carolina at Chapel Hill (UNC-CH). This study was approved by the institutional review board at UNC-CH. Between 1994 and 2002, 28 (8.8%) children with radio- graphically documented inner ear malformations received co- chlear implants at UNC-CH. Before implantation, all children had documented severe to profound or profound sensorineural HL and failed an appropriate hearing-aid trial. Most children partic- ipated in an intensive auditory-based therapy program. Preoper- ative imaging, intraoperative findings, postoperative complica- tions, and performance were reviewed. High-resolution computed tomography (HRCT) scans were reviewed for each patient by at least two experienced observers. The findings were categorized as shown in Table I, with examples illustrated in Figure 1. Mondini’s malformation was defined as per the original description: incompletely partitioned (IP) cochlea (i.e., dysplasia) with fusion of the apical turns, dilated vestibule, and enlarged vestibular aqueduct (EVA). 23 For the purposes of this article, this is referred to as the constellation of IP, EVA, and a dilated vestibule. Common cavity (CC) was defined as no inter- nal differentiation into either a vestibular or cochlear bud. EVA was measured at the midportion of the posterior semicircular canal (SCC) and considered abnormal if greater than 2 mm in From the W. Paul Biggers, MD, Carolina Children’s Communication Disorders Program (CCCDP), Department of Otolaryngology–Head and Neck Surgery, University of North Carolina, Chapel Hill, North Carolina, U.S.A. Editor’s Note: This Manuscript was accepted for publication August 25, 2003. Send Correspondence to: Dr. Craig A. Buchman,G0412 Neuroscience Hospitals, CB # 7600, Chapel Hill, NC 27599-7600, U.S.A. E-mail: buchman@med.unc.edu Laryngoscope 114: February 2004 Buchman et al.: Inner Ear Malformations 309