Objective: To evaluate the benefits of routine prophylactic drainage in extraperitoneal anastomoses in elective colorectal surgeries. Methods: Systematic review of the literature and meta-analysis of randomized clinical trials. The electronic databases PubMed, Embase and Lilacs were searched. Included studies evaluated the benefits of routine prophylactic drainage in elective extraperitoneal colorectal surgery compared to non-drainage. Results: 9310 studies were identified. After reading the titles and abstracts, 99 studies were found to be duplicate publications and another 9,202 were excluded for not meeting the inclusion criteria. Nine studies remained for full analysis, of which five were excluded for not complying with Cochrane Collaboration eligibility criteria for controlled clinical trials. Thus, four randomized controlled clinical trials involving a total of 1147 participants were selected for data extraction and subsequent meta-analysis. Clinical dehiscence at the site of the anastomosis was compared in four studies (1120 participants, DM = 0.01, 95% CI = -0.01 to 0.03, P = 0.85, I2 = 0%);radiological dehiscence was compared in three studies (651 participants, DM = 0.75, 95% CI = 0.38 to 1.49, P = 0.63, I2 = 0%); mortality was compared in three studies (651 participants, DM = 0.83, 95% CI = 0.39 to 1.77, P = 0.98, I2 = 0%); extra-abdominal infections were compared in four studies (1120 participants, DM = 0.81, 95% CI = 0.60 to 1.09, P = 0.83, I2 = 0%); the reoperation rate was compared in three studies (1061 participants, DM = 0.97, 95% CI = 0.70 to 1.35, P = 0.14, I2 = 48%); operative wound infection was compared in three studies (651 participants, DM = 1.02, 95% CI = 0.54 to 1.93, P = 0.26, I2 = 25%); and intestinal obstruction compared in three studies (1020 participants, DM = 1.43, 95% CI = 0.96 to 2.13, P = 0.58, I2 = 0%). Conclusion: in the currently available literature there is no high-quality scientific evidence demonstrating benefits from prophylactic drainage of extraperitoneal colorectal anastomoses in elective surgery
