Pulmonary sequestration is a relatively uncommon aberration of the lung that is characterized by lung tissue that has a systemic arterial supply . It accounts for up to 6% of congenital pulmonary malformations . If a sequestration is identified, resection is generally required because of the risks of infection and misdiagnosis as a malignant lesion . Intralobar sequestration accounts for 75% of pulmonary sequestrations diagnosed, of which 98% are located in the lower lobes and the majority (58%) on the left side . Thus, accurate location of the aberrant artery is necessary.
To determine the detailed anatomy of the anomalies, we used 3-dimensional (3D) CT imaging (data not shown), which is known to confirm both the presence of the artery and the relevant anatomy . In our cases, we detected the aberrant arteries using 3D CT images to clarify specific anatomical nuances such as the presence of a pleural aberrant artery or a large-diameter artery.
VATS lobectomy has been successfully performed to excise sequestrated lung lobes [8,11-13]. When we first began performing lobectomies for sequestration, we occluded the artery centrally using double ligation before peripherally transecting the artery (data not shown); however, this proved to be unnecessary. We currently use only one stapler intra operatively, even in the presence of very large vessels, and we have not observed stapler failure in any of our VATS lobectomies. Intraoperative bleeding typically occurred during preparation of the aberrant artery and other lobectomy procedures in a previous report . Chung et al. reported that when the renal artery and vein were stapled simultaneously using an endovascular GIA stapler (Echelon Flex 60 mm, 2.5 load Endo-cutters; Ethicon Endo-Surgery), there was no clinical evidence of bruit 12 months postoperatively . That is, there was no evidence of stapling-related morbidity from the transection of systemic arteries such as the renal artery.
In fact, in the present study, there were no significant differences between ligation and stapling in terms of morbidity or mortality. Although endoscopic stapling is widely used to transect large-diameter vessels, particular care must be taken when it is used to transect an artery feeding from the aorta. This is to prevent massive bleeding caused by incomplete closure of the artery, which can occur if the endoscopic staple cutter malfunctions. Fortunately, this did not occur in the present cases. However, Liu et al. reported that one of their VATS cases was converted to thoracotomy because of injury to the aberrant artery . Additionally, when the aberrant artery was thickened or had become fragile because of recurrent infections, they often ligated the artery proximally using silk sutures before cutting it with a stapler in order to ensure a solid stump . In the case, that the aberrant artery is fragile, it may be necessary to ligate the aberrant artery prior to stapling.
In this experiment, we selected three types of stapling cartridges: white, blue, and green. Although blue and green cartridges are not routinely used, in the experimental portion of the present study, the pig vessels were denatured because of preservation such as freezing. Furthermore, we used pig vessels from the descending aorta, which were of larger diameter and thickness than are aberrant arteries associated with pulmonary sequestrations. We therefore had to use blue and green cartridges in our experiment. The results of our experimental model with pig aortas reveal that it is necessary to select the stapling cartridge based on the size of the aberrant artery (Table 1). In fact, an unsuitable cartridge appeared to weaken the staple line, whereas appropriate selection resulted in a solid stump capable of withstanding pressures of approximately 300 mmHg. In other words, using only adequate stapler cartridge made us handle the water leakage from pig aortas in this experiment. Therefore, it is acceptable that an aberrant artery can be successfully transected with minimal invasion when resecting pulmonary sequestrations with a stapler alone. In fact, we achieve similar results for both ligation and stapling in clinical cases. Final, VATS procedure using a stapler and an adequate cartridge device is increasingly employed.