Endoscopic stapedotomy: a comparison between 4 mm and 3 mm nasal endoscope.

Background: Although, both the microscopic and endoscopic stapes surgery have claimed a parallel audiological outcome, the comparison between two standard endoscopes (4 mm and 3 mm) in endoscopic stapedotomy is not well documented. We have compared the clinical utility and audiological outcomes of the 3 mm and 4 mm rigid nasal endoscopes in the primary endoscopic stapedotomy.
Materials and Methods: This is a retrospective study conducted in the Department of Otorhinolaryngology between June 2015 and May 2018. Total 46 patients of primary otosclerosis had undergone endoscopic stapedotomy where 3 mm and 4 mm nasal endoscopes have been used in 22 (group A) and 24 patients (group B) respectively. The preoperative, intraoperative and postoperative surgical findings including the hearing outcomes were compared between the two groups.
Results: One patient (4.5%) in group A and 6 (25%) patients in group B required canaloplasty (p = 0.00, χ ² test) and 7 (31.18%) patients in group A and 18(75%) in group B had required curettage of the bony canal wall (p = 0.04, χ ² test). There was no significant difference in the air-bone gap between the two groups (p = 0.85).
Conclusion: Both 3 mm and 4 mm nasal endoscopes can be successfully used in the endoscopic stapedotomy providing a parallel visual field. Although, comparable results can be obtained in preserving the chorda tympani nerve, tympanic membrane, facial nerve, and postoperative giddiness including the audiological outcomes, the requirement of the canaloplasty and curettage of posterior bony canal can be significantly reduced in patients operated with 3 mm nasal endoscope, especially in patients with narrow/over angulated external auditory canal.