Re-Evaluating Anatomical Determinants of Foreign Body Aspiration in Adults

Objectives: Tracheobronchial foreign-body aspiration is a clinically significant condition in adults. Although classical teaching attributes the right-sided predominance to the steeper, shorter, and wider morphology of the right main bronchus, this explanation has not been empirically validated in patients with confirmed foreign-body aspiration. Methods: This retrospective study included adult patients (≥18 years) who underwent bronchoscopic removal of foreign bodies from the right or left main bronchus between 2012 and 2025. Only individuals with available preoperative chest radiographs were analyzed. Measurements included tracheobronchial angles, bronchial and tracheal diameters, bronchial lengths, and estimated airway volumes calculated under cylindrical assumptions. Results: Of 35 included patients, 26 (74.3%) had right-sided and 9 (25.7%) had left-sided bronchial foreign bodies. At the population level, the right main bronchus was significantly steeper, wider, and shorter than the left; however, these anatomical differences did not distinguish patients with right- versus left-sided foreign bodies. Tracheobronchial angles, tracheal dimensions, bronchial diameters, and diameter ratios were all similar between the two groups (p > 0.05). In contrast, right bronchial length and volume were significantly greater in patients with right-sided foreign bodies (p = 0.004 for both). Exploratory ROC analysis further suggested that a right bronchial length exceeding 23.28 mm may be associated with an increased tendency toward right-sided migration within this cohort. Conclusions: Increased right bronchial length and volume may facilitate a preferential pathway for airflow continuity toward the right bronchial tree. These findings challenge long-standing anatomical assumptions and highlight the need to incorporate geometric and airflow-dynamic factors into future models of aspiration mechanics.