Onuki Takamasa, Kanzaki Masato, Wachi Naoko, Isaka Tamami, Sakamoto Kei, Maeda Hideyuki, Oyama Kunihiro, Murasugi Masahide
Department of Surgery I, Tokyo Women's Medical University, Tokyo, Japan
Department of Surgery I, Tokyo Women's Medical University, Tokyo, Japan.
Interact Cardiovasc Thorac Surg. 2016 Jul;23(1):26-30. doi: 10.1093/icvts/ivw030. Epub 2016 Mar 30.
Although various types of segmentectomy are frequently performed for resecting lung tumours at present, there is no clear answer to the question what kind of segmentectomy would be more efficient for performing lymphadenectomy. Learning the embryological mechanism of the segment formation could be one of the methods for selecting the surgical procedure. To investigate the developmental mechanism of the lung, this study focused on 'sharing structure', a unique 3D structure consisting of the bronchi and pulmonary arteries. In the structure, two arteries from different directions, after straddling the bronchus in the central part, share one bronchial tree at the peripheral part.
Using computed tomography data obtained before segmentectomy, this study observed the 'sharing structure' in 193 left and right upper lobe cases. This study investigated the relationship between the segmental arterial types and the straddled bronchi, which were straddled by the pulmonary arteries found in the centre of the sharing structure.
In the right upper lobes, the straddled bronchi were anterior segmental bronchi. In the left upper lobes, however, the straddled bronchi of the lingular interlobar pulmonary artery type contained no anterior segmental bronchi. But, the straddled bronchi of lingular mediastinal pulmonary artery type contained anterior segmental bronchi in all cases.
Although pulmonary arteries in almost all sharing structures in the right upper lobes straddled anterior bronchi, those in mediastinal type and interlobar type in the left upper lobe were found to straddle the anterior and apicoposterior bronchi, respectively. These findings indicated that the interlobar type was speculated to be rotating mediastinal type backward in the embryonic period. This study strongly suggested a new concept that 'the lung segments never continuously exist from the early stage of the embryonic period as units, but they are only simple units artificially named by their prevailing bronchial branching patterns'. Therefore, during segmentectomy including lymphadenectomy for pulmonary tumours, the retrieval of the branching patters of pulmonary arteries could allow the segmentectomy to become more efficient with considering the formations of lung lobes.
尽管目前各种类型的肺段切除术常用于切除肺部肿瘤，但对于哪种肺段切除术在进行淋巴结清扫时更有效这一问题，尚无明确答案。了解肺段形成的胚胎学机制可能是选择手术方式的方法之一。为了研究肺的发育机制，本研究聚焦于“共享结构”，这是一种由支气管和肺动脉组成的独特三维结构。在该结构中，来自不同方向的两条动脉在中央部分跨越支气管后，在周边部分共享一个支气管树。
本研究利用肺段切除术前行计算机断层扫描获得的数据，观察了193例左右上叶病例的“共享结构”。研究了肺段动脉类型与在共享结构中心发现的被肺动脉跨越的支气管之间的关系。
在右上叶，被跨越的支气管为前段支气管。然而，在左上叶，舌叶叶间肺动脉型的被跨越支气管中不包含前段支气管。但是，舌叶纵隔肺动脉型的被跨越支气管在所有病例中均包含前段支气管。
尽管右上叶几乎所有共享结构中的肺动脉都跨越前段支气管，但左上叶纵隔型和叶间型中的肺动脉分别被发现跨越前段支气管和尖后段支气管。这些发现表明，叶间型被推测为在胚胎期向后旋转的纵隔型。本研究强烈提出了一个新的概念，即“肺段并非从胚胎期早期就作为单位连续存在，而是仅仅是根据其主要支气管分支模式人为命名的简单单位”。因此，在包括肺部肿瘤淋巴结清扫的肺段切除术中，考虑肺叶的形成，检索肺动脉的分支模式可使肺段切除术更有效。
