Background: The occurrence of type II endoleaks after endovascular repair of aortic aneurysm has gradually gained increasing attention. We present a case of a patient with an expanding aneurysm after thoracic endovascular aortic repair (TEVAR) for a type II endoleak, in which successful direct ligations of the intercostal artery. Case Presentation A 62-year-old male patient who had previously undergone TEVAR for a descending thoracic aortic aneurysm presented ongoing chest discomfort. Approximately four years prior, he developed an intramural hematoma along with a descending thoracic aortic aneurysm (5.7 cm), which led to his zone 3 TEVAR procedure using a Medtronic Valiant thoracic endograft. Three years later, due to the expansion of an aortic aneurysmal sac, he underwent an additional TEVAR procedure under suspicion of type IA or B endoleak. However, due to the continuous growth of the descending thoracic aortic aneurysm (5.9 cm) and the suspicion of a type II endoleak, the decision was made to proceed with open repair. In cases where a type II endoleak is detected, it was planned to directly ligate the intercostal arteries suspected of causing the endoleak. We performed a left thoracotomy and following longitudinal opening of the chronic descending aortic aneurysm, we detected and cleared the old hematoma and debris, noting ongoing bleeding. Multiple ligations of the intercostal artery were performed using pledgeted prolene 3-0 sutures. On day two of postoperative care, the computed tomography (CT) confirmed the absence of any abnormalities at the surgical site and ruled out the presence of an endoleak Conclusions: In a case involving TEVAR for a thoracic aortic aneurysm, open suture ligations were used to treat type II endoleaks without having to resort to CPB, resulting in successful outcomes.