Background and Aims: The prevalence of obesity is growing at alarming rate, and has become a major global health problem. Laparoscopic gastric bypass surgery is the most common type of weight loss surgery. With the development of technology and equipment, 3D laparoscopic system has increasingly entered the field of general surgery. The three-dimensional stereo vision overcomes the shortage of the traditional 2D laparoscopic vision system that lacks the vertical perception and stereo views of the anatomy, and thereby provides a better surgical visual field for the primary surgeon, which allows more procedural accuracy and reduces the surgical difficulty to some extent. However, as a major renovation in laparoscopic technique, there are few reports on application of 3D laparoscopic system in gastric bypass surgery, and its advantages and disadvantages comparing with 2D laparoscopic system are unknown. Therefore, this study was designated to assess the superiority of 3D laparoscopic system in gastric bypass surgery and its application value by a single-center randomized controlled trial. 
Methods: Between August 2017 and March 2019, 60 patients seeking weight-loss treatment in the 4th Affiliated Hospital of China Medical University were enrolled, and were randomly assigned to two groups, with 30 cases in each group, and then underwent 2D laparoscopic gastric bypass surgery (2D group) and 3D laparoscopic gastric bypass surgery (3D group), respectively. The time for the completion of each surgical procedure (creating the small stomach pouch, gastrojejunostomy, and jejunojejunostomy) and the total operative time were compared between the two groups, and the subjective perceptions in operability and operating comfort of the surgeon under laparoscope were scored by questionnaire survey.
Results: There were no significant differences in the general data between the two groups of patients before operation (all P>0.05). In 3D group compared with 2D group, except the time for making small stomach pouch which showed no significant difference (P=0.120), the time for gastrojejunostomy (P=0.015) and the time for jejunojejunostomy (P=0.012) as well as the total operative time (P=0.023) were significantly reduced. The subjective scores of the surgeon for accuracy, layering perception and vertical perception and the scores for eye-fatigue sensation and neck-fatigue sensation under 3D laparoscope were all superior to those under 2D laparoscope (all P<0.05).
Conclusion: Compared with 2D laparoscopic system, 3D laparoscopic system can significantly shorten the operative time and increase the operating comfort of the surgeon in performing gastric bypass surgery. So, it has excellent application prospects.