Single- versus two- layer intestinal anastomosis: a meta-analysis of randomized controlled trials

Randomized controlled trials comparing single- with two-layer intestinal anastomosis were identified using a systematic search of Medline, Embase and the Cochrane Library Databases covering articles published from 1966 to 2004. Outcome of primary interest was postoperative leak. A risk ratio for trial outcomes and weighted pooled estimates for data were calculated. A fixed-effect model weighted using Mantel-Haenszel methods and a random-effect model using DerSimonian-Laird methods were employed.Six trials were analyzed, comprising 670 participants (single-layer group, n = 299; two-layer group, n = 371). Data on leaks were available from all included studies. Combined risk ratio using DerSimonian-Laird methods was 0.91 (95% CI = 0.49 to 1.69), and indicated no significant difference. Inter-study heterogeneity was significant (χ2 = 10.5, d.f. = 5, p = 0.06).No evidence was found that two-layer intestinal anastomosis leads to fewer post-operative leaks than single layer. Considering duration of the anastomosis procedure and medical expenses, single-layer intestinal anastomosis appears to represent the optimal choice for most surgical situations.The basic principles of intestinal suture were established more than 100 years ago by Travers, Lembert and Halsted [1], and have since undergone little modification. Development of stapling instruments for intestinal anastomosis has added new dimensions to intestinal surgery. Two systematic reviews of randomized controlled trials (RCTs) comparing stapled with hand-sewn colorectal anastomosis found no difference between the two methods [2,3], but colorectal surgeons need to be familiar with both. Unsurprisingly, hand-suturing techniques were shown to display a longer learning curve than stapling [4]. One aspect of intestinal suturing technique that has remained controversial is the use of either one or two layers of sutures for anastomosis.Historically, two-layer anastomosis using interrupted silk sutures for an outer inverted se