Anatomical analysis of variations in the bronchus pattern of the left upper lobe using three-dimensional computed tomography angiography and bronchography

Background: Number of sublobar resections performed is increasing, thoracic surgeons must be familiar with bronchus anatomy and preoperative planning plays an important role in predicting anatomical variations. However, there is few report showing anatomic variations of the left upper lobe (LUL) using three-dimensional computed tomography angiography and bronchography (3D-CTAB), and no in Chinese population. The present study aimed to use 3D-CTAB to describe variations of the pulmonary bronchus of LUL in Chinese population. Methods: In this retrospective study, we analyzed 3D-reconstruction from patients that performed lobectomy, segmentectomy or subsegmentectomy of the LUL in 2020 at Fujian Medical University Cancer Hospital's Department of Thoracic Surgery. Patients with previous LUL surgery or absence of 3D-reconstruction or without surgery were excluded. Results: One hundred and sixty-six patients met our criteria. Branching of the left upper bronchus was classified into bifurcated type (99.4%) or trifurcated type (0.06%). The left upper divisional bronchus (B1+2+3) arise as bifurcated (65.65%) or trifurcated type (34.34%). Apicodorsalis bronchus (B1+2) always originated as bifurcated type, while ventralis bronchus (B-3) was either bifurcated (94.45%) or trifurcated (5.55%). Lingular bronchus (B4+5) was observed as bifurcated (96.38%) or trifurcated (3.62%) type. When analyzing sublobar divisions of bronchi a total of 14 subtypes were identified, 6 of them were found in the upper divisional bronchus. Conclusions: Bronchial anatomy of LUL is highly variable, especially in upper divisional bronchus. 3D-CTAB is a useful tool to identify variations in the bronchi pattern, we recommend preoperative planning for sublobar resection.