title: Factors affecting final facial nerve outcome following vestibular schwannoma surgery.
abstract: OBJECTIVE
  To determine factors affecting facial nerve outcome of vestibular schwannoma surgery.
  
  
  METHODS
  This retrospective cohort study comprised 652 patients. The outcome measure was House-Brackmann classification at two years post-operatively. Univariate and multivariate analyses were carried out to determine the factors affecting facial nerve outcome. The incidence rates of hemifacial spasm, metallic taste and crocodile tear syndrome were recorded.
  
  
  RESULTS
  For tumours less than 1.5 cm, 95 per cent of outcomes were normal, 100 per cent were satisfactory (House-Brackmann grades I-III) and 0 per cent were unsatisfactory (grades IV-VI). For tumours 1.5-2.4 cm, 83 per cent of outcomes were normal, 99 per cent were satisfactory and 1 per cent were unsatisfactory. For tumours 2.5-3.4 cm, 68 per cent of outcomes were normal, 96 per cent were satisfactory and 4 per cent were unsatisfactory. For tumours 3.5-4.4 cm, 52 per cent of outcomes were normal, 80 per cent were satisfactory and 20 per cent were unsatisfactory. For tumours larger than 4.4 cm, 50 per cent of outcomes were normal, 72 per cent were satisfactory and 28 per cent were unsatisfactory.
  
  
  CONCLUSIONS
  Tumour size and operation year were significant predictors of facial nerve outcome. The surgical learning curve was steepest for the first 50 patients.
authors.affiliation: Neuro-otology and Skull Base Surgery Department, Addenbrookes Hospital,Cambridge University Teaching Hospitals NHS Trust,UK.
authors.forename: D A
authors.initials: DA
authors.lastname: Moffat
authors.affiliation: Centre for Applied Medical Statistics,University of Cambridge,UK.
authors.forename: R A
authors.initials: RA
authors.lastname: Parker
authors.affiliation: Neurosurgery Department, Addenbrookes Hospital,Cambridge University Teaching Hospitals NHS Trust,UK.
authors.forename: D G
authors.initials: DG
authors.lastname: Hardy
authors.affiliation: Neurosurgery Department, Addenbrookes Hospital,Cambridge University Teaching Hospitals NHS Trust,UK.
authors.forename: R
authors.initials: R
authors.lastname: Macfarlane
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D007758:Ear, Inner / Q000473:pathology / Q000601:surgery; D005154:Facial Nerve / Q000473:pathology / Q000502:physiology / Q000601:surgery*; D005155:Facial Nerve Diseases / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D019569:Hemifacial Spasm / Q000209:etiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D013506:Otologic Surgical Procedures / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D013651:Taste Disorders / Q000209:etiology; D013666:Tears; D016896:Treatment Outcome; D055815:Young Adult