title: Consequences to hearing during the conservative management of vestibular schwannomas.
abstract: OBJECTIVE
  To estimate the risk of loss of serviceable hearing during the conservative management of vestibular schwannomas.
  
  
  METHODS
  Retrospective case review.
  
  
  METHODS
  Twenty-five patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively for a mean duration of 43.8 months (range, 12-194 mo). The pure-tone average (PTA) (0.5, 1, 2, and 3 kHz) and speech discrimination scores (SDS) were measured at regular intervals throughout the entire duration of follow-up. Serviceable hearing was defined using two criteria: 70% SDS/30 dB PTA (the 70/30 rule) and 50% SDS/50 dB PTA (the 50/50 rule). The size and growth rate of tumors were determined according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines (1995). Intervention was recommended if there was evidence of continuous or rapid radiological tumor growth, and/or increasing symptoms or signs suggestive of tumor growth.
  
  
  RESULTS
  The risk of loss of serviceable hearing for the total group was 43% using the 70/30 rule and 42% using the 50/50 rule. Tumor growth was considered significant (> 1 mm) in 8 tumors (32%) and nonsignificant in 17 (68%). The risk of loss of serviceable hearing for the tumor-growth group was 67% using the 70/30 rule and 80% using the 50/50 rule. In contrast, the risk of loss of serviceable hearing for the no tumor-growth group was 25% using the 70/30 rule and 14% using the 50/50 rule. No audiological factors predictive of tumor growth were identified.
  
  
  CONCLUSIONS
  There is a significant risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. This risk appears to be greater in tumors that demonstrate significant growth.
authors.affiliation: Department of Otolaryngology, University Health Network, Toronto General Hospital, University of Toronto, Ontario, Canada.
authors.forename: R M
authors.initials: RM
authors.lastname: Walsh
authors.forename: A P
authors.initials: AP
authors.lastname: Bath
authors.forename: M L
authors.initials: ML
authors.lastname: Bance
authors.forename: A
authors.initials: A
authors.lastname: Keller
authors.forename: J A
authors.initials: JA
authors.lastname: Rutka
mesh_terms: D000328:Adult; D001301:Audiometry, Pure-Tone; D004428:Ear Neoplasms / Q000150:complications* / Q000473:pathology / Q000628:therapy; D005260:Female; D034381:Hearing Loss / Q000209:etiology*; D006801:Humans; D007759:Labyrinth Diseases / Q000150:complications* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications* / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies; D014722:Vestibule, Labyrinth