The bronchial segmentation and its anatomical variations. A clinical-anatomic and bronchoscopy study.

The development in interventional respiratory medicine entails the need of bronchial anatomical knowledge, whose variations assume their greatest importance nowadays. The aim of this study was to describe the frequency of these variations and to analyze the bronchial lengths, barely registered before in literature. This observational descriptive study (from June 2018 until April 2019) was conducted in a sample of 17 pairs of lungs, which were dissected and measured at the Cadaver Donation Centre (Universidad Complutense, Madrid), and a second sample of 50 bronchoscopies, performed at the San Carlos Clinic Hospital, which were analyzed during the procedure. Our results show that there are no significant differences in the incidence of variations by sex in any of both samples, and neither in the average length of any bronchus by sex nor lobar pattern. Left main bronchus presents the longest length and left upper lobe bronchus the shortest. The highest percentage of variations is contained in the right lower lobe (25.4%), and the most frequent variation in the subsuperior bronchus (B*) (19.4%). The middle lobe and the left lower lobe present the lowest percentage of variations (11.9%). Only 37.3% of the pairs of lungs/patients did not have any anatomical variation in the general sample. Despite of the small size of the sample, results show a high percentage of variations and a minority of completely normal pairs of lungs, which invites us to reflect about the probable high prevalence of variations in the general population. Further studies with greater samples are needed to confirm our hypothesis.