Postoperative bleeding requiring a reoperation after a VATS procedure is reported to be 0.6%  and surgical devices are often responsible [2,3,4,5]. An endostapler is one of the most essential devices for a VATS and could cause parenchymal injury by the direct contact of the reinforced materials [3, 6] or tip of the stapler itself [2, 5]. However, the delayed bleeding due to the protruding edge of the staple line has not been previously described in the literature.
In our case, multiple firings of the endostapler created a sharp protruding edge, and the subsequent lung expansion would have promoted a direct contact between the protruding edge and parietal pleura resulting in delayed bleeding. This risk would be more significant in wedge resection cases because of the larger residual lung volume preserved which is expected to have a better lung expansion and facilitate the direct contact of the staple line and parietal pleura.
We should have paid much more attention to prevent an irregular cut line by adjusting the trajectory and insertion angle of the endostapler. Further, we should have overlaid the staple line with a surgical sealant once the protruding edge became evident. The physical isolation between the lung and parietal pleura might have avoided the contact bleeding.