Background: A newly available, laparoscopic 5-mm bipolar vessel sealing device promises substantial advantages over the 10-mm instrument. This study compared the safety as well as the technical and surgical aspects of these different tools. Methods: For this study, 30 consecutive patients undergoing laparoscopic left-sided colectomy were prospectively randomized for the 5-mm LigaSure or The 10-mm LigaSure. The patients' demographics were analyzed together with their intraoperative and postoperative parameters, and the instruments were assessed by the surgeons with a standardized questionnaire. Results: The two groups were comparable and demonstrated similar mean operation times, blood losses, and hospital stays. The 5-mm LigaSure was applied in more operation steps and resulted in fewer bleeding episodes and less lens cleaning. Monopolar scissors were used less frequently in the 5-mm group, thus minimizing cauteric lesions and their complications (0 in the 5-mm group vs 2 in the 10-mm group). Overall satisfaction with the 5-mm LigaSure was significantly higher (8.4±0.18 vs 6.9±0.41 out of 10; p=0.002), with significant advantages in terms of dissection capacity, visibility, and handling. Conclusion: The 5-mm LigaSure is as secure and fast as the larger 10-mm device and compares favorably in terms of finer dissection as well as trocar flexibility and handling. Therefore, it can be used safely in laparoscopic colorectal surger
