Table of Contents:
Background: In thoracic surgery branches of the pulmonary artery have to be divided and are closed with ligatures, sutures or staplers, usually in combination or performed twice. Until now advanced bipolar impedance controlled instruments fail regularly in larger vessels and can’t reach burst pressure values compared to the mentioned methods. In this study we wanted to know if we can improve the bur-sting pressures especially in case of larger pulmonary arteries by double sealing.
Methods: Experiments were carried out 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: 1-6mm, 7-12mm and >12mm. The groups (n=12 in each) were investigated for each vessel size: ligature, single seal, double seals separated by gap of 0.5cm and double seals separated by gap of 1.0cm. 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. In addition preparations of the vessels were analyzed histologically after hematoxylin and eosin staining.
Results: The ligated vessels in the 1-6mm group showed the highest bursting pressures (mean 515.7 ± 39.6mbar). Mean bursting pressure in the single seal group was 231.6 ± 47.5mbar. This was not significantly different from the group with double seals placed 0.5cm apart. However, bursting pressures were signi-ficantly higher in the group with double seals placed 1cm apart (p < 0.001). Mean value in this case was 308.5 ± 44.5mbar. In the 7-12mm vessels, mean bursting pressure was highest with ligation at 361 ± 67.1mbar but was significantly higher in both groups with double bipolar seals (180.3 ± 52.1mbar with 0.5cm separation and 277.0 ± 64.5mbar with 1cm separation) than in the single seal group (102.7 ± 16.1mbar). In large vessels (>12 mm), mean bursting pressures were low (66.3 ± 12.7mbar) with single seals but were significantly higher with double seals (162.3 ± 35.8mbar [0.5cm separation] and 137.3 ± 22.9mbar [1cm separation]).
Conclusions: In the ex vivo model of the pulmonary artery, double seals revealed significantly higher bursting pressures than single seals, even in those whose diameters larger than 12mm. If there is enough vessel length, the two seals should be placed 1cm apart.