Objective Assessment of Postoperative Gastrointestinal Motility in Elective Colonic Resection Using a Radiopaque Marker Provides an Evidence for the Abandonment of Preoperative Mechanical Bowel Preparation

Background: It has been suggested that mechanical bowel preparation (MBP) has no benefit in terms of anastomotic healing, infection rate, or improvement in the postoperative course in patients undergoing elective colorectal surgery, and that it should be abandoned. However, the effect of MBP on postoperative gastrointestinal motility has been assessed subjectively. In this randomized trial, we objectively assessed the effect of MBP on postoperative gastrointestinal motility and mobility in elective colonic resection. Method: In total, 79 patients scheduled to undergo elective colonic resection for cancer were randomized to MBP or no-MBP groups prior to surgery. All patients ingested radiopaque markers before surgery to evaluate postoperative gastrointestinal motility, objectively evaluated by the transition of the markers at postoperative days (PODs) 1, 3, 5 and 7. The groups were then further subdivided into open and laparoscopic-assisted colectomy (LAC) groups and evaluated in terms of gastrointestinal motility and postoperative mobility. Results: There was no significant difference between the no-MBP and MBP groups in terms of perioperative and postoperative course. In the LAC subgroup, there was no significant difference between the no-MBP and MBP groups in terms of marker transition. However, in the open subgroup, there was a significant difference between the groups in terms of the residual ratio of markers in the small intestine at POD 3 (no-MBP 35.3% vs. MBP 69.2%; p=0.041), excretion rate of markers at POD 5 (no-MBP 49.7% vs. MBP 8.8%; p=0.005), and residual ratio in the small intestine at POD 7 (no-MBP 3.1% vs. MBP 28.8%; p=0.028). Additionally, the excretion rate in the no-MBP group was significantly higher than in the MBP group at POD 7 (74.1% vs. 33.8%; p=0.007). Conclusions: Our data provide additional evidence to support the abandonment of MBP in elective open colonic surgery.