Anatomical variations of round window in different age groups and surgical difficulties associated with them during cochlear implantation

Abstract

Introduction: Round window (RW) insertion of the electrodes during cochlear implantation is the most favorable route considered by many surgeons. The objective of this study was to review the anatomy of the RW based on visibility and accessibility of RW niche (RWN) and RW membrane (RWM) and to assess their implications in surgical difficulties during cochlear implantation in different age groups. Materials and Methods: This was a retrospective observational study conducted at the Department of ear, nose, and throat-Head and Neck Surgery, Institute of Medicine, Kathmandu, Nepal. We analyzed the record data of all the cochlear implants from January 2015 to December 2019 for the visibility of RWM, RWN, and associated surgical difficulties in different age groups. RWM visibility was classified as; Grade I (>50% of RWM is visible), Grade II (25%–50% of RWM is visible), Grade III ( 15 years, Type B (eight cases) was the most common variant of RWN and Type II (six cases) was the most common variant of RWM. There was a statistically significant association between the visibility of the RWN and RWM and the visibility of RWN and different levels of surgical difficulty (P