Role of transanal drainage tubes in preventing anastomotic leakage after low anterior resection: a meta-analysis of randomized controlled trials

Background The transanal drainage tube (TDT) is thought to reduce the incidence of anastomotic leakage (AL) in patients with low anterior resection (LAR). However, results from different clinical trials are inconsistent, although nearly all meta-analyses agree on the efficacy. In contrast to results of many previous studies, 2 recent independent randomized controlled trials (RCTs) suggest that the use of TDT does not prevent AL. We performed a meta-analysis including only RCTs to compare patients with TDTs vs. those without TDTs in terms of AL rate. Methods A systematic literature search was performed in the PubMed, Embase, Cochrane Library databases, Clinicaltrials.gov and WHO/ICTRP from inception until February 14, 2022. RCTs that evaluated the role of TDTs in AL prevention in patients who underwent LAR for rectal cancer were included. A meta-analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Data were extracted by two authors independently, and random-effects models were implemented. The main outcome was AL, and the secondary outcome was the grade of AL. Results Three RCTs were included involving a total of 1115 participants (559 patients in the TDT group and 556 in the non-TDT group). No significant difference in the AL rate was detected (RR = 0.69, 95% confidence interval (CI) 0.42-1.15, p = 0.15, I-2 = 21%, very low certainty evidence). The incidence of grade C AL was possibly lower in the TDT group (RR = 0.33, 95% CI 0.11-1.01, p = 0.05, very low certainty evidence), while the rate of grade B AL was similar between the two groups (RR = 1.17, 95% CI 0.66-2.08, p = 0.59, very low certainty evidence). Conclusions The present meta-analysis suggests that TDTs are not effective in reducing the overall incidence of AL, but possibly have a potential benefit in reducing the occurrence of grade C AL in patients with LAR. Based on the current limited data and existing heterogeneity, the inclusion of larger populations and the identification of more uniform indications for TDT need to be addressed in future studies.

Automated summary

This study found that compared to patients without TDT, there was no significant reduction in the incidence of anastomotic leakage in patients with TDT, but there may be a potential benefit in reducing the occurrence of grade C anastomotic leakage.