Discovery of lung surface intersegmental landmarks by three-dimensional reconstruction and morphological measurement

The lack of anatomic landmarks between segments on the lung surface makes the identification of intersegmental planes one of the greatest challenges in anatomic segmentectomy. Therefore, with the aim to determine the landmarks of intersegmental planes on the lung surface, we used three-dimensional (3D) reconstruction and morphological measurement techniques to reconstruct stereoscopic models of all pulmonary segments, and measured the length of each segment on the lung surface along the lobe's anatomic landmark lines.

We downloaded the primary computed tomography (CT) scan data of 619 patients and imported them into a 3D reconstruction system, which could automatically reconstruct the 3D model of the trachea-bronchi system. We manually reconstructed the intersegmental veins to ensure the accuracy of segmental boundary. The 3D models of pulmonary segments could be reconstructed based on the bronchial tree and the pathways of the intersegmental veins. We then measured the length of each segment on the lung surface along the lobe's anatomic landmark lines and calculated the proportions between these lengths.

Complete 3D segmental models were successfully reconstructed in 500 patients (241 male and 259 female), and the lengths of every segment on the lung surface along the lobe's anatomic landmark lines were measured. Our data revealed that the length of each segment on lung surface varied among individuals. However, the proportions between these lengths stayed constant, even when stratified by gender, age, height, and weight.

We discovered that the proportion between the lengths of adjacent segments on the lung surface stayed constant. The constant proportion reflected and uncovered the lung surface intersegmental landmarks, which could help direct surgeons to identify intersegmental planes during anatomic segmentectomy in an easy and safe way without additional cost.