Comparison of the 3D-Exoscope and Operating Microscope in Mastoidectomy

Objectives The operating microscope (OM) commonly used in ear surgeries has several disadvantages, including a low depth of field, a narrow field of view, and unfavorable ergonomic characteristics. The exoscope (EX) was developed to overcome these disadvantages. Herein, we compared OM and EX during mastoidectomy and found out the feasibility of the EX. Study Design Prospective randomized comparative study. Setting Tertiary academic medical center. Patients Patients who had mastoidectomy for chronic otitis media with or without cholesteatoma between January 2022 and April 2022. Intervention Canal wall-up mastoidectomy (CWUM) or canal wall-down mastoidectomy (CWDM) using OM or EX without endoscope. Main Outcome Measures Operative setting time (the time between the end of general anesthesia and incision), operative time (from incision to suture), postoperative audiologic outcomes, perioperative complications, and the decision to switch from EX to OM. Results Of 24 patients who were diagnosed with chronic otitis media or cholesteatoma, 12 each were randomly assigned to the OM or EX group. The mean operation time was 175 ± 26.5 minutes and 172 ± 34.6 minutes in the EX and OM group, respectively, which was not significantly different ( p = 0.843). The procedures in the EX group were successfully completed using a three-dimensional (3D)-EX without conversion to OM. All surgeries were completed without any complications. The postoperative difference in the air and bone conduction was 11.2 and 12.4 dB in the EX and OM groups, respectively, which was not significantly different ( p = 0.551). Conclusions EX is comparable to OM in terms of surgical time, complications, and audiologic outcomes following mastoidectomy. The EX system is a potential alternative to OM. However, further improvements are required to overcome some drawbacks (deterioration of image resolution at high magnification, requirement of an additional controller for refocusing).