Positional Variations and Surgical Implications of Bony Overhangs in the External Auditory Canal

Abstract

Background: This study examines the anatomical differences in the external auditory canal (EAC), particularly bony overhangs that hinder middle ear access, affecting diagnosis and surgical procedures. It seeks to categorize these overhangs for better surgical planning, offering a classification system essential for otologists and middle ear surgeons aiming at improved surgical outcomes. Materials and Methods: This retrospective analysis at a tertiary care hospital reviewed patient records and surgical videos from November 2017, focusing on otological procedures. Excluding individuals with EAC erosions or previous surgeries, it recorded demographics, diagnoses, and details of surgeries, including bony overhang locations. The study employed descriptive statistics, Chi-squared tests, and predictive analysis to explore the impact of bony overhangs on surgical requirements. Results: This study analyzed 333 ears from 305 patients undergoing middle ear and mastoid surgeries, finding a significant association between EAC types and bony overhang distribution, confirmed by a Chi-square test (P value ≈ 1.63 × 10 −83). Despite a predominance of female patients (59%), no significant correlation was observed between EAC types and patient age or gender. However, disease duration showed a significant relationship with EAC types, with predictive analysis indicating a high likelihood of requiring canalplasty for specific EAC configurations. Conclusion: Our research presents a clinical classification for EAC and tympanic annulus overhangs, underscoring their role in surgical visibility and middle ear operation challenges. It corroborates earlier studies, stressing the need to grasp EAC variations for improved surgical planning, overcoming obstacles, and enhancing middle ear surgery outcomes, thus refining surgical methods for patients with such anatomical differences.