title: Round window otosclerosis: radiologic classification and clinical correlations.
abstract: OBJECTIVE
  To develop a radiologic classification of severity of round window involvement in otosclerosis and describe the impact of each class on hearing and outcome of stapes surgery.
  
  
  METHODS
  Retrospective chart review with radiologic review of computed tomographic scans.
  
  
  METHODS
  Hospital and private otolaryngology clinics.
  
  
  METHODS
  We reviewed computed tomographic scans of 930 ears with clinical otosclerosis; 121 (13%) had round window involvement, with no pericochlear involvement in 41 of these-the primary subjects of the study. A control group consisted of 15 ears with stapedial otosclerosis.
  
  
  METHODS
  Round window involvement was classified into 5 groups from isolated round window edge hypodensity (RW-I) to overgrowing obliteration with possible extension to the cochlea (RW-V). Hearing measures included 4-frequency pure-tone average air conduction, bone conduction, and air-bone gap (ABG).
  
  
  RESULTS
  Of the 41 ears, 17.1%, 31.7%, 34.1%, and 17.1% were classified as RW-I to RW-IV, respectively. Patients with RW-I and RW-II otosclerosis, compared with the controls, showed no statistically significant differences in preoperative hearing or in ABG after stapes surgery. Patients with RW-III otosclerosis had significantly poorer hearing and a larger postoperative ABG (mean, 15 dB) than controls and groups RW-I and RW-II, whereas the RW-IV group showed the most severe hearing loss and poorest surgical outcome (all p's ≤ 0.001).
  
  
  CONCLUSIONS
  The proposed classification for round window otosclerosis is a valuable clinical tool that can help in decisions regarding, and counseling about, stapes surgery. Classes RW-I and RW-II have no clinical impact. Patients with RW-III otosclerosis may have a mild residual gap after surgery; those with RW-IV have dramatically poorer results.
authors.affiliation: Division of Otolaryngology HNS, Faculty of Medical Sciences, Lebanese University, Beirut, Lebanon. drsalahmansour@gmail.com
authors.forename: Salah
authors.initials: S
authors.lastname: Mansour
authors.forename: Karen
authors.initials: K
authors.lastname: Nicolas
authors.forename: Hassan Haidar
authors.initials: HH
authors.lastname: Ahmad
mesh_terms: D000328:Adult; D001299:Audiometry; D016208:Databases, Factual; D005260:Female; D034381:Hearing Loss / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D010040:Otosclerosis / Q000000981:diagnostic imaging* / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D012405:Round Window, Ear / Q000000981:diagnostic imaging* / Q000601:surgery; D012720:Severity of Illness Index; D016896:Treatment Outcome