[Is the debate on mechanical bowel preparation, before colorectal surgery, over?].

The present "point of view" tries to assess the state of the art in 2008 on the role of mechanical bowel preparation before colorectal surgery. The case of bowel preparation has been questioned by several meta-analyses of small randomized trials, suggesting also its detrimental effect in terms of anastomotic leaks. In 2007 two large trials were published and pooling their data suggested an increased risk of deep abscesses when bowel preparation was omitted. A further meta-analysis including all published data on this topic appeared useful. This meta-analysis included almost 5 000 patients and showed bowel preparation involves no benefit in terms of surgical site infections, with more infections after bowel preparation (Odds ratio 1.40 [1.05-1.87]). Sensitivity analysis showed an increased risk of abscesses when bowel preparation was omitted but this risk is not clinically relevant since the number needed to harm was as high as 333 patients. In conclusion this meta-analysis including a huge number of patients does not confirm the detrimental effect of bowel preparation but did not show any benefit of it; these conclusions being valid only for colonic surgery, rectal surgery needing further studies.