Prophylactic anastomotic drainage for colorectal surgery.

BACKGROUND: There is little agreement on prophylactic use of drains in anastomoses in elective colorectal surgery despite many randomized clinical trials. Results of these trials are contradictory, quality and statistical power of these individual studies have been questioned. Once anastomotic leakage has occurred it is generally agreed that drains should be used for therapeutic purposes. However, on prophylactic use no such agreement exists.

OBJECTIVES: Comparison of safety and effectiveness of routine drainage and non-drainage regimes after colorectal surgery. The following hypothesis was tested: The use of prophylactic anastomotic drainage after elective colorectal surgery does not prevent development of complications.

SEARCH STRATEGY: The studies were identified from CINAHL, EMBASE, LILACS, MEDLINE, Controlled Clinical Trials Database, Trials Register of the Cochrane Colorectal Cancer Group, reference lists.

SELECTION CRITERIA: Randomized controlled trials comparing drainage with non-drainage regimes after anastomoses in elective colorectal surgery were reviewed. Outcome measures were: 1. mortality; 2. clinical anastomotic dehiscence; 3. radiological anastomotic dehiscence; 4. wound infection; 5. reoperation; 6. extra-abdominal complications.

DATA COLLECTION AND ANALYSIS: Data were independently extracted and cross-checked by the two reviewers. The methodological quality of each trial was assessed. Details of the randomization (generation and concealment), blinding, and the number of patients lost to follow-up were recorded. The RCTs were stratified based on experimental group, according to clinical homogeneity (external validity).

MAIN RESULTS: Of the 1140 patients enrolled (6 RCTs), 573 were allocated for drainage and 567 for no drainage. The patients assigned to the drainage group compared with the ones assigned to non-drainage group showed: a) Mortality: 3% (18 of 573 patients) compared with 4% (25 of 567 patients); b) Clinical anastomotic dehiscence: 2% (11 of 522 patients) compared with 1% (7 of 519 patients); c) Radiological anastomotic dehiscence: 3% (16 of 522 patients) compared with 4% (19 of 519 patients); d) Wound infection: 5% (29 of 573 patients) compared with 5% (28 of 567 patients); e) Reintervention: 6% (34 of 542 patients) compared with 5% (28 of 539 patients); f) Extra abdominal complications: 7% (34 of 522 patients) compared with 6% (32 of 519 patients).

REVIEWERS' CONCLUSIONS: There is insufficient evidence showing that routine drainage after colorectal anastomoses prevents anastomotic and other complications.