Background There is little agreement on prophylactic use of drains in anastomoses in elective colorectal surgery despite many randomized clinical trials. Once anastomotic leakage occurs it is generally agreed that drains should be used for therapeutic purposes. However, on prophylactic use no such agreement exists.
Aim To compare the safety and effectiveness of routine drainage and nondrainage regimes after elective colorectal surgery. The primary outcome was clinical anastomotic leakage.
Methods A systematic search was undertaken to identify randomized clinical trials. Of the 1140 patients who were enrolled (six randomized controlled trials), 573 were allocated for drainage and 567 for no drainage. Outcome measures were: (i) mortality: 3% (18 of 573 patients) compared with 4% (25 of 567 patients); (ii) clinical anastomotic dehiscence: 2% (11 of 522 patients) compared with 1% (7 of 519 patients); (iii) radiological anastomotic dehiscence: 3% (16 of 522 patients) compared with 4% (19 of 519 patients); (iv) wound infection: 5% (29 of 573 patients) compared with 5% (28 of 567 patients); (v) reintervention: 6% (34 of 542 patients) compared with 5% (28 of 539 patients); (vi) extra-abdominal complications: 7% (34 of 522 patients) compared with 6% (32 of 519 patients). None of these differences in outcome was significant.
Conclusion There is insufficient evidence showing that routine drainage after colorectal anastomoses prevents anastomotic and other complications.