The resected area of the posterior wall of the external auditory canal during transcanal endoscopic ear surgery for cholesteatoma

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) mm(2). 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) mm(3). The correlation coefficient (R-2) 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). Conclusion: These results suggest that the resected area was minimal and of an appropriate size relative to the volume of the cholesteatoma. (C) 2016 Elsevier Ireland Ltd. All rights reserved.