Surgical results of tympanoplasty after conversion to the endoscopic approach performed by a surgeon experienced in microscopic surgery

Purpose The aim of this study was to analyze the surgical outcomes of endoscopic tympanoplasty (ET) type I, and to investigate the learning curve of ET type I in a surgeon experienced in microscopic surgery. Methods We retrospectively studied patients with tympanic membrane perforations who had undergone ET type I from January 2015 to June 2020. All procedures were performed by a single senior surgeon with considerable microscopic experience. We compared the perforation closure rate in relation to age, previous ear surgery history, graft material, size, and location of perforation. We compared the operation time according to the number of operated patients. Results A total of 399 patients were enrolled. The success rate of ET type I was 92.7%. Age, prior ear surgery, graft material, size, and location of perforation did not influence the surgical outcomes. The surgical time for the initial ten cases was the longest (78.3 min), and stabilized after the first 100 cases to under 60 min. The surgical success rate was 96.0% in the first 50 cases, and decreased to approximately 92% afterwards. Conclusion The surgical time largely decreased with the number of operated patients. Since the operations were performed by a surgeon experienced in microscopy, the success rate of initial cases was not low, even though the operation time of these initial cases was longer. We believe that endoscope provides a new perspective on ear surgery if it could overcome the difficulties in the early stage.