In this study, the reasons for prolonged hospital stay after thoracoscopic (video- or robot-assisted) anatomical lung resections are investigated. Currently, whenever possible, these anatomical lung resections are performed thoracoscopically, as they offer significant improvements in terms of postoperative pain, number of postoperative complications, rehabilitation, tolerance for adjuvant chemotherapy, and length of hospital stay. The development of an 'Enhanced Recovery After Surgery' (ERAS) protocol for lung surgery has further reduced hospital stay and the need for opioids for analgesia. Despite the optimal implementation of the ERAS protocol, there are still patients who need to stay in the hospital longer than the median. The aim of this research is to investigate the reasons for this.