Anatomical distribution and clinical significance of translobar bronchi, arteries, and veins hidden in the interlobar fissure.

Background: The interlobar bronchovascular structures hidden in the incomplete interlobar fissures (IFs) are often inadvertently transected during pulmonary resections, which could inevitably lead to accidental injury and potentially compromise the function of the preserved area. A thorough examination of the anatomical distribution of translobar bronchi, arteries, and veins holds significant clinical importance.

Methods: Three-dimensional computed tomography bronchography and angiography (3D-CTBA) data from patients who underwent pulmonary resection between December 2018 and November 2019 were retrospectively analyzed. The translobar bronchi, arteries, and veins were categorized based on their origin and distribution. Surgical results of patients who underwent surgery involving translobar structures were further reviewed.

Results: Among the 310 enrolled patients, incomplete IFs (IIFs) were most frequently observed in horizontal fissures (68.7%), followed by right upper oblique fissures (42.3%), left lower oblique fissures (32.6%), left upper oblique fissures (12.9%), and right lower oblique fissures (11.0%). The incidence of bronchovascular structures was significantly higher in IIFs than in complete IFs (CIFs; 85.5% 5.2%, χ=1,021.1, P<0.001). A total of three subtypes of translobar bronchi, five subtypes of translobar arteries, and 14 subtypes of translobar veins were identified. Primary subtypes of translobar arteries (frequency >5%) included the left A (18.7%) that branched from A and the common trunk of right Asc.A+A (6.1%). Primary subtypes of translobar veins (frequency >5%) included the right V draining into inferior pulmonary vein (IPV) (5.8%), the interlobar Vb (58.4%) within horizontal fissures, the right V draining into V (26.1%), the left V draining into IPV (7.4%), the right V draining into V (38.4%), and the common trunk of left IPV and superior pulmonary vein (SPV; 9.4%). Moreover, 12.0% of translobar arteries and 75.0% of translobar veins were mistransected during anatomical pulmonary resection, resulting in gas-exchanging dysfunction in the preserved territory.

Conclusions: Translobar bronchovascular structures exhibited a high incidence and were more commonly present in IIFs. Surgeons should pay increased attention to these structures to prevent accidental injuries during anatomical pulmonary resection.