Cochlear Implantation in Isolated Large Vestibular Aqueduct Syndrome: Report of Three Cases and Literature Review

THIEME Case Report Cochlear Implantation in Isolated Large Vestibular Aqueduct Syndrome: Report of Three Cases and Literature Review Rabindra Pradhananga1,2 Kiran Natarajan3 AmarNath Devarasetty3 1 Department of ENT-Head and Neck Surgery, Tribhuvan University Teaching Hospital, Kathmandu, Nepal 2 Department of Implantation Otology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India 3 Department of Otorhinolaryngology, Madras ENT Research Foundation, Chennai, Tamil Nadu, India Mohan Kameswaran2 Address for correspondence Rabindra Pradhananga, MS, Fellowship in Implantation Otology; Department of ENT-Head and Neck Surgery, Tribhuvan University Teaching Hospital, Kathmandu, Nepal, Kathamandu þ977, Nepal (e-mail: ; ). Int Arch Otorhinolaryngol 2015;19:359–363. Abstract Keywords ► large vestibular aqueduct ► cochlear implantation ► CSF gusher Introduction Large vestibular aqueduct syndrome (LVAS) is characterized by the enlargement of the vestibular aqueduct associated with sensorineural hearing loss. It is the most common radiographically detectable inner ear anomaly in congenital hearing loss. LVAS may occur as an isolated anomaly or in association with other inner ear malformations. Objective To report three cases of isolated LVAS with a focus on preoperative assessment, surgical issues, and short-term postoperative follow-up with preliminary auditory habilitation outcomes. Resumed Report One girl and two boys with LVAS were assessed and cochlear implantation was performed for each. Various ways of intraoperative management of cerebrospinal fluid gusher and postoperative care and outcomes are reported. Conclusion Cochlear implantation in the deaf children with LVAS is feasible and effective. Introduction The vestibular aqueduct (VA) is a tiny, bony canal in the otic capsule that originates on the medial wall of the vestibule and extends toward the cerebellar face of the petrous pyramid at the posterior cranial fossa. It contains the endolymphatic duct connecting the endolymphatic sac and the vestibule. It has an average diameter of 0.6 to 1.5 mm at its midpoint between the common crus and its opening at the posterior cranial fossa.1,2 The VA derives from a diverticulum formed in the wall of the otocyst during the fifth week. The aqueduct begins as a short, broad pouch but gradually elongates and thins until it achieves its characteristic J shape of adulthood.3 A premature arrest in development produces an abnormally short and broad VA. received August 24, 2014 accepted October 11, 2014 published online November 14, 2014 DOI http://dx.doi.org/ 10.1055/s-0034-1395791. ISSN 1809-9777. When this anatomical anomaly of large VA is associated with hearing loss, it is referred as large vestibular aqueduct syndrome (LVAS). LVAS is usually bilateral. Valvassori and Clemis were the first to describe and name LVAS after finding the association between a large VA and sensorineural hearing loss (SNHL) in 50 cases.1 Cochlear implantations were performed in 99 congenital prelingual deaf children of less than 6 years in the first 5 months of 2014 in our institute. Among them, isolated LVAS was detected in three. The aim of the study was to report these three cases of isolated LVAS focusing mainly on preoperative assessment, surgical issues, and short-term postoperative follow-up with preliminary auditory habilitation outcomes measured in terms of Categories of Auditory Copyright © 2015 by Thieme Publicações Ltda, Rio de Janeiro, Brazil 359 360 Cochlear Implantation in Isolated LVAS Pradhananga et al. Category Criteria 7 Uses telephone with known speaker 6 Understands conversation without lip-reading tation was beneficial for the treatment of hearing loss in LVA as well as in the control patients.7 Chen et al compared 62 infants with LVAS for development of auditory skills after cochlear implant and found results similar to those of infants with a normal inner ear.8 5 Understands common phrases without lip-reading Case Reports 4 Discriminates speech sounds without lip-reading 3 Identifies environmental sounds 2 Responds to speech sounds 1 Aware of environment sounds 0 Not aware of environmental sounds Table 1 Category of Auditory Performance Performance (CAP; ►Table 1) and Speech Intelligibility Rating (SIR; ►Table 2) scores. Literature Review Enlargement of the VA is diagnosed radiographically, when its anteroposterior diameter exceeds 1.5 mm on computed tomography (CT) scan of temporal bone, measured midway between its aperture and crus communes.1,4 In many cases, LVA accompanies malformation of the cochlea and/or SCCs (semi-circular canals). It also may be the sole radiographically detectable abnormality of the inner ear in a child with hearing loss (isolated LVAS). More commonly, LVAS is associated with nonsyndromic deafness. But it can also be associated with syndromic hearing loss as in Pendred syndrome, branchio-oto-renal syndrome, and CHARGE syndrome (coloboma of the eye, heart defects, atresia of the nasal choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness). It has been postulated that LVAS is inherited as an autosomal recessive trait.5 Cochlear implantation effectively increases both auditory perception and speech and language development in children with LVAS.6 Most of the literature reported cerebrospinal fluid (CSF) gusher or leak as a common problem encountered during and after cochlear implantation.6 Miyamoto et al published results of a retrospective case-control study on outcomes of cochlear implantation in 23 patients with LVAS and 46 control patients and concluded that cochlear implan- Case 1 A 25-month-old boy presented to the Implant Outpatient Department with a history of trouble hearing, first noticed by the parents at the age of 8 months, with delay in speech and language development. The child was born at full term by cesarean section with a birth weight 1.9 kg. There was no history of maternal illnesses including TORCH [toxoplasmosis, other (syphilis, varicella-zoster, parvovirus B19), rubella, cytomegalovirus, and herpes infection], Rh-incompatibility, neonatal jaundice, or meningitis. His other developmental milestones were within normal limits. There was no history of visual disturbances, hypothyroidism, syncopal spells, or urinary disturbances. General examination showed normal IQ with no neurologic dysfunction. Ear, nose, and throat (ENT) examination showed normal external ear with normal and healthy-looking tympanic membrane. There was no response to tuning fork tests in either ear. Other ENT examination was within normal limits. The patient underwent detailed audiological workup. Behavioral audiometry showed profound SNHL in both ears. Tympanogram showed A-type curve in both ears. Brainstem evoked response audiometry (BERA) showed absent wave V on both sides at 90-dB nHL (normal Hearing Level) at the rate of 19.3/s using click and tone bu (...truncated)