Standardized computed tomographic imaging and dimensions of the round-window niche.

Abstract

Both the increasing usage of intratympanic medication to the inner ear through the round window and the popularity of cochlear implantation have raised interest in the anatomy of the round-window niche (RWN). The objectives of this study were to measure the RWN and to standardize a computed tomographic projection for measuring it. We included patients of all ages who underwent computed tomography for various reasons. We measured computed tomographic images acquired from 214 patients aged 4-85 years and included 414 ears and excluded 14 inflamed "wet" ears. We measured depth, width, and shape of the RWN and skull width. The RWN dimensions did not change with age, whereas the skull width increased with age in both genders throughout the patients' entire life. Folds and soft tissue could not be demonstrated in computed tomographic imaging. In conclusion, a special oblique projection that clearly demonstrates the RWN was reconstructed, and this reconstruction allows for standardized measuring.