title: Cochlear implant electrode array misplaced in Hyrtl's fissure.
abstract: Hyrtl's fissure is a cleft that is present in the developing fetal petrous temporal bone and extends from the area inferior to the round window to the meninges of the posterior fossa. Persistent Hyrtl's fissure, due to incomplete ossification, is considered a rare temporal bone malformation, and is a known cause of perilabyrinthine cerebrospinal fluid fistula. Very few cases are reported as being at risk of complication of cochlear implant surgery. Here we report the case of an 8-year-old boy with misplacement of an electrode array in Hyrtl's fissure. The diagnosis was made postoperatively, since cochlear implant failure was suspected from non-auditory responses. Computed tomography (CT) revealed the extracochlear location of the electrode array. We emphasize the role of presurgical imaging CT and magnetic resonance imaging in detecting temporal bone abnormalities, and we discuss the value of intraoperative auditory nerve response telemetry and postoperative radiological evaluation in diagnosing cochlear implant misplacement.
authors: Department of Otorhinolaryngology Head & Neck Surgery, Beni Messous Universitary Hospital, Alger 1600, Algeria.
authors: Amina
authors: A
authors: Mouzali
authors: Kheiredidine
authors: K
authors: Ouennoughi
authors: Mohamed-Salah
authors: MS
authors: Haraoubia
authors: Omar
authors: O
authors: Zemirli
authors: Jean Michel
authors: JM
authors: Triglia
mesh_terms: D002648:Child; D019929:Cochlear Implantation / Q000009:adverse effects* / Q000379:methods; D003054:Cochlear Implants; D020878:Device Removal; D004567:Electrodes, Implanted / Q000009:adverse effects*; D005500:Follow-Up Studies; D005547:Foreign Bodies / Q000175:diagnosis / Q000209:etiology*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019300:Medical Errors; D035583:Rare Diseases; D012086:Reoperation / Q000379:methods; D018570:Risk Assessment; D013701:Temporal Bone / Q000002:abnormalities*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome