Introduction: Mechanical preparation of the colon (MPC) in colorectal surgery has been a dogma that has been questioned over the last few years. The objective of this study is to demonstrate that morbidity in scheduled colorectal surgery is the same or lower without MPC.
Material and method: Patients subjected to scheduled left colon and rectal surgery with primary anastomosis randomised into two groups. The "Preparation" group (MPC) received MPC and the "non-preparation" group (No-MPC) had only cleaning enemas. The variables collected were: demographic, oncological, nutritional, risk prediction models and morbidity-mortality.
Results: Of the 193 patients included: 69 received MPC and 71 did not; 89 patients with colocolic anastomosis (MPC, 38; no MPC, 51) and 50 colorectal (MPC, 31; no MPC, 19). Statistically significant differences were seen in the overall analysis in favour of "no preparation" as regards morbidity (43.55 % with MPC and 27% with No MPC) and nosocomial infection (27.5% and 11.4%). There was 11.6% wound infections in the MPC compared to 5.7% in the no MPC, which was not statistically significant. The only mortalities were in the MPC group 2/69 (2.9% of patients). As regards the location of the anastomosis, in the colocolics the differences were more pronounced, with statistically significant differences in the morbidity, anastomosis dehiscence, and nosocomial infection variables. The effect of no MPC was not so evident in colorectal anastomosis.
Conclusions: Our results suggest that there is no benefit in MPC before surgery in colocolic anastomosis. No-MPC is not associated with a higher morbidity in wound infection or anastomotic dehiscence. In colorectal anastomosis the differences are not so evident, therefore a much bigger series needs to be studied.