title: The resected area of the posterior wall of the external auditory canal during transcanal endoscopic ear surgery for cholesteatoma.
abstract: OBJECTIVE
  The aim of this study was to evaluate part of the area of the posterior wall of the external auditory canal (EAC) that is resected during transcanal endoscopic ear surgery (TEES) for cholesteatomas that extend to the mastoid cavity, and to determine whether TEES is a minimally invasive surgical procedure for cholesteatoma.
  
  
  METHODS
  This was a retrospective study involving 25 patients with cholesteatoma that extended to the mastoid cavity, and who underwent surgery between October 2014 and October 2015. The patients' cholesteatomas were removed using TEES. In this procedure, the superoposterior wall of the EAC was resected in order to access the deepest part of the cholesteatoma. We made a paper template by tracing the shape of the resected EAC and then reconstructed the resultant defect with a piece of cartilage, the size of which was based on the size of the template. We evaluated the size and greatest dimension of the resected part of the EAC by measuring the template. Preoperatively, we also evaluated the volume of each cholesteatoma on computed tomography (CT) images.
  
  
  RESULTS
  The median size of the resected region was 37.3 (14.7-68.4)mm2. The median length of the greatest dimension of the resected area was 8.7 (5.1-15.9)mm. The median cholesteatoma volume was 417 (43-1399)mm3. The correlation coefficient (R2) obtained using a two-thirds order approximation curve for the relationship between the resected tissue area and the cholesteatoma volume (0.617) was higher than that obtained by linear approximation (0.387).
  
  
  CONCLUSIONS
  These results suggest that the resected area was minimal and of an appropriate size relative to the volume of the cholesteatoma.
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Imai
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan. Electronic address: snishiike@osakah.johas.go.jp.
authors.forename: Suetaka
authors.initials: S
authors.lastname: Nishiike
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Tsuruta
authors.affiliation: Department of Otorhinolaryngology - Head & Neck Surgery, Osaka Rosai Hospital, Japan.
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Tomiyama
mesh_terms: D000328:Adult; D000368:Aged; D002356:Cartilage / Q000637:transplantation; D018424:Cholesteatoma, Middle Ear / Q000000981:diagnostic imaging / Q000601:surgery*; D004424:Ear Canal / Q000601:surgery*; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008416:Mastoid / Q000601:surgery*; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D013506:Otologic Surgical Procedures / Q000379:methods*; D019651:Plastic Surgery Procedures; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Cholesteatoma; Minimal invasive surgery; Quantitative measurement; Transcanal endoscopic ear surgery