title: Facial nerve stimulation in the narrow bony cochlear nerve canal after cochlear implantation.
abstract: To evaluate the correlation between a narrow bony cochlear nerve canal (BCNC) and facial nerve stimulation (FNS) after cochlear implantation (CI) and their underlying mechanisms and to predict the risk of FNS preoperatively.
  
  
  
  Retrospective cohort study.
  
  
  
  A total of 64 pediatric cases that underwent CI were included. Among them, 32 cases experienced FNS after CI, and another 32 cases were selected from 817 pediatric implantees by stratified random sampling. The width of the BCNC, the status of the cochlear nerve (CN) and the internal auditory canal (IAC), T level, and C level were compared and analyzed. Strategies for eliminating FNS were also analyzed.
  
  
  
  The FNS group showed a narrower BCNC (1.09 ± 0.52 mm) than the control group (1.99 ± 0.61 mm; P < .01), a lower CN/facial nerve ratio (0.32 ± 0.36) than the control group (1.34 ± 0.76; P < .01), and narrower IAC diameter (4.06 ± 1.71 mm) than the control group (5.66 ± 1.36 mm; P < .01). The FNS group also showed higher T level (165.7 ± 28.3 μA) than the control group (142.2 ± 21.2 μA; P < .01). Adjustment of the C levels and/or pulse width and switching off offending electrodes were attempted to eliminate FNS, with a 75.0% success rate. The FNS group still showed low Categories of Auditory Performance scores (3.00 ± 1.90) compared with the control group (5.94 ± 1.41, P < .01) after adjustment.
  
  
  
  A narrow BCNC could be a cause of FNS after CI. Therefore, careful selection of the side for CI and programming strategies are required to reduce FNS.
  
  
  
  4. Laryngoscope, 126:1433-1439, 2016.
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.|Department of Otorhinolaryngology , Korea University Ansan Hospital, Ansan, Republic of Korea.
authors.forename: Yoon Chan
authors.initials: YC
authors.lastname: Rah
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Young-Sun
authors.initials: YS
authors.lastname: Yoon
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Moon Young
authors.initials: MY
authors.lastname: Chang
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Myung-Whan
authors.initials: MW
authors.lastname: Suh
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Seung-Ha
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Sun O
authors.initials: SO
authors.lastname: Chang
authors.affiliation: Department of Otorhinolaryngology , Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Moo Kyun
authors.initials: MK
authors.lastname: Park
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D019929:Cochlear Implantation / Q000009:adverse effects*; D003056:Cochlear Nerve / Q000503:physiopathology / Q000601:surgery; D005154:Facial Nerve / Q000503:physiopathology / Q000601:surgery; D005155:Facial Nerve Diseases / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D013701:Temporal Bone / Q000033:anatomy & histology* / Q000294:innervation / Q000601:surgery; D016896:Treatment Outcome
keywords: Cochlear implantation; bony cochlear nerve canal; facial nerve stimulation