Advantages of ET over MT
One of the primary advantages of the endoscope is the panoramic and wide angle surgical view with magnification. In contrast, the microscope has a straight-line view, which can be limited when encountering variations of the EAC, such as a tortuous, stenotic ear canal and bony overhangs. Therefore, surgeons may need to drill out or curette bony overhangs during canaloplasty and canal wall curettage for complete visualization and assessment of the TM and the status of ossicles. In the present study, the rate of these required additional maneuvers was significantly lower in ET than in MT since the endoscope can be approximated to the surgical field, bypassing the narrowing parts of the EAC, and the angled endoscope can be rotated to obtain all-round vision without the requirement of these invasive maneuvers, thereby reducing morbidity and operative time. In agreement with our findings, Tseng C-C et al34, Lee S-Y et al35 and Pap I et al36 reported a significantly lower canaloplasty rates in ET than in MT.
In agreement with Lee S-Y et al35 and Pap I et al36, another significant advantage regarding ET is that the operative time for ET was significantly shorter than for MT. The surgeon’s experience and the learning curve generally have an impact on the operative time. However, MT consumes more time due to frequent manipulation of the patient’s head or repeated microscope adjustment for a better view, using the post-auricular approach, or performing canaloplasty and curettage. According to Hsu Y-C et al, the relatively short time required for surgery and under anaesthesia results in the significantly fewer medical resources expended on ET and decreased complications from prolonged exposure to anaesthesia.37 In our meta-analysis, the analysis for operative time data suffers from significant heterogeneity and publication bias.
Characteristically, ET is advantageous concerning safety, minimal invasiveness and the rate of complications. Because of a wide field of view with magnification, ear surgeons have obtained minimally invasive endoscope-assisted tympanoplasty accompanied by minimal complications. In our meta-analysis, we focused particularly on the following complications: the infection (wet ear), wound gap, visible scar, nausea and vomiting. No significant difference was found between both techniques with regard to infection and wound gap, but there was a highly significant decrease in the rates of visible scar, nausea and vomiting as well as the overall complications rate in favour of ET. Postoperatively, the wet ear results from a severe middle ear infection37 and the wound gap following suture removal from early loose stitches27 rather than the procedure itself. In the present study, a meta-analysis of cosmetic results through the presence or absence of a visible scar revealed that the endoscope was definitely preferred over the microscope. For ET, the transcanal approach to the middle ear and smaller incision with minimum tissue dissection for harvesting a graft lead to early wound healing and less scarring on the graft donor site.16,18,26Besides, avoiding the post-auricular route reduces the incidence of auricular displacement and asymmetry of the pinna yielding better cosmetic outcomes.12,14,19,22 Similar to meta-analytic results of visible scar, the rates of nausea and vomiting were significantly lower after ET than after MT. Nausea and vomiting are unpleasant events and are associated with patient discomfort and dissatisfaction during postoperative recovery.38 These two adverse events require administration of various treatment modalities and consequently can expand recovery room time, increase nursing care requests and the duration of hospital stay, and can further increase total healthcare costs.39
In concordance with our results regarding complications, Lee S-Y et al35 reported that wound problems of ET were significantly lower than those of MT, but there was no significant difference between ET and MT regarding wet ear.