Background: The benefits of a valid pneumoperitoneum in laparoscopic surgery are counterbalanced by the possible negative effects of increased abdominal pressure and carbon dioxide (CO2) insufflation, which are crucial factors in causing postoperative pain. The purpose of this work is to evaluate the effectiveness of the valveless trocar (VT) insufflation system in decreasing postoperative pain and influencing operative time, compared to a standard insufflation system. Methods: A systematic research was performed using MEDLINE, EMBASE, Central Cochrane Library, and CINAHL Plus for studies published up to June 2020. Randomized controlled trials (RCTs) on adult population evaluating the effects of VT versus a standard insufflation system in laparoscopic surgery and reporting postoperative pain level and operative time were included in the analysis. Data and study quality indicators were extracted independently by 2 authors using a standardized form. Statistical analysis was based on a random effect model, using the inverse variance method. Results: We identified 3 RCTs for a total of 245 patients. The meta-analysis showed a statistically significant reduction in shoulder pain with the use of VT at 24 hours: mean difference (MD) -7.9% (95% confidence interval [95% CI]: -1.29 to 0.29; z = 3.08; P = .002) and a nonstatistically significant increase in operation time: MD 5.80 (95% CI: -8.93 to 20.54; P = .44). Conclusion: Our study suggests a better shoulder pain control at 24 hours postoperation using new-generation VT for laparoscopic surgery compared to standard insufflation system. Weak evidence of increased operating time with the VT was observed considering only two of the three RCTs. PROSPERO registration number: CRD42020191835.
Keywords: insufflation system; laparoscopic surgery; operative time; pneumoperitoneum; postoperative pain; valveless trocar.