With the further development of new surgical techniques, that allow for the performance of a variety of standard diagnostic and therapeutic procedures in a less invasive fashion, it is instructive to look at the complications of these new techniques, in order to define their role for general thoracic surgery. 372 patients have been treated by means of video-assisted thoracic surgery (VATS) between 1/1992 and 12/1994. A total of 934 open thoracic procedures were performed in the same time frame, 399 out of them for the same chest disorders as treated by VATS alternatively. In 40 cases (10.7%) the endoscopic procedure had to be converted to an open thoracotomy. The main reasons for conversion were inability to locate or resect lesions due to a deep or central position (n = 13), requirement of further resection (n = 10), adhesions (n = 9), fibrinopurulent empyema (n = 5), bleeding (n = 2) and single-lung-ventilation failure (n = 1). The mean operation time was significantly shorter with VATS compared to open procedures, except for decortications. The mean hospital stay was 4.2 days in the endoscopic and 7.9 days in the thoracotomy group. Cost analysis for both techniques included expenses for disposable instruments, the operation room, anesthesia, and total hospital charges. Higher costs for instruments for VATS procedures were compensated by shorter chest drainage, less postoperative need for analgetics and a significantly shorter hospital stay.(ABSTRACT TRUNCATED AT 250 WORDS)