Double Bipolar Sealing of the Pulmonary Artery Improves the Bursting Pressures

Background In every anatomic lung resection, branches of the pulmonary artery have to be divided. In open surgery, this can be done with ligatures or staplers. In endoscopic surgery, only an endostapler can be used. By routing we ligate the vessels double. Bipolar sealing had yielded promising results, so we wanted to know if we can improve the bursting pressures especially in case of larger vessels by double sealing. Methods Experiments were performed on preparations of the left pulmonary artery extracted at the slaughterhouse. A pressure sensor was implanted at the central end to provide digital measurement of the pneumatic load on the vessel seal and thus establish bursting pressure in each case. Vessels were sealed with MARSEAL 5 (Gebrüder Martin GmbH & Co KG, Tuttlingen, Germany) and SealSafe G3 electric current. The vessels investigated were separated into three sizes: 1 to 6 mm, 7 to 12 mm, and >12 mm. The groups (n = 12 in each) were investigated for each vessel size-Group 1: ligature; Group 2: single seal; Group 3: double seals separated by gap of 0.5 cm; and Group 4: double seals separated by gap of 1.0 cm. Mean bursting pressure (mbar) was calculated for each group. Differences between groups were calculated with Mann-Whitney U test; differences with p < 0.05 were considered significant. Results The ligated vessels in the 1 to 6 mm group showed the highest bursting pressures (mean 515.7 ± 39.6 mbar). Mean bursting pressure in the single seal group was 231.6 ± 47.5 mbar. This was not significantly different from the group with double seals placed 0.5 cm apart. However, bursting pressures were significantly higher in the group with double seals placed 1 cm apart (p < 0.001). Mean value in this case was 308.5 ± 44.5 mbar. In the 7 to 12 mm vessels, mean bursting pressure was highest with ligation at 361 ± 67.1 mbar but was significantly higher in both groups with double bipolar seals (180.3 ± 52.1 mbar with 0.5-cm separation and 277.0 ± 64.5 with 1-cm separation) than in the single seal group (102.7 ± 16.1 mbar). In large vessels (>12 mm), mean bursting pressures were low (66.3 ± 12.7 mbar) with single seals but were significantly higher with double seals (162.3 ± 35.8 mbar [0.5-cm separation] and 137.3 ± 22.9 mbar [1-cm separation]). Conclusions In the ex vivo model of the pulmonary artery, double seals revealed significantly higher bursting pressures than single seals. If there is enough vessel length, the two seals should be placed 1 cm apart.