To reduce the risk of postoperative infectious complications and anastomotic leakage in colorectal surgery, preoperative mechanical bowel preparation (MBP) is performed routinely. The aim of this study was to evaluate the safety of primary anastomosis in elective colorectal surgery without MBP.

From Jan. 2005 to Dec. 2006, three hundred and seventy-nine patients of elective colorectal surgery with primary anastomosis were performed with MBP in 352 cases (Prep group) and without MBP in 24 cases (Non-prep group). For preoperative MBP, 4 liters of polyethylene glycol solution was administered. Postoperative infectious complications and other morbidity were reviewed with medical records and prospectively collected data.

Demographic, clinical and treatment characteristics did not differ significantly between the two groups. The overall rate of abdominal infectious complications (wound infection, anastomotic leak) was 2.9 % in the Prep group and 9 % in the Non-prep group (P > 0.05). Anastomotic leak occurred in nine patients (2.6%) in the Prep group and one (4.5%) in the Non-prep group.

The incidence of infectious complications after elective colorectal surgery without MBP did not differ significantly compare to that with MBP. However, prospective, randomized clinical trial is needed to assess the safety of primary anastomosis in elective colorectal surgery without MBP.