Kohn's pores are not responsible for collateral ventilation between inflated and deflated segments: a microscopic study of pulmonary intersegmental septa in the human lung.

The composition of the pulmonary intersegmental septum has not been clearly identified by thoracic surgeons who regard Kohn's pores as the main channel that causes air leakage when determining the intersegmental septum by segmental ventilation. In this study, we aimed to examine this possible misinterpretation by focusing on a detailed description of the microscopic anatomy of the intersegmental septum. To accomplish this aim, 50 lung samples of the intersegmental septum from fresh cadavers without emphysema were studied by histological and electron microscopy. The findings of light microscopy and electron microscopy showed that the intersegmental septum is composed of three layers. The alveolar walls of adjacent segments serve as the superficial layer. They are integral, and no Kohn's pores were identified. The deep layer contains collagen fibres. As shown by our findings, Kohn's pores are absent within the intersegmental septum. Therefore, they could not be the main channel for the collateral ventilation between inflated and deflated lung segments during a pulmonary segmentectomy.