BACKGROUND 1 2 3 2 4 10 6 7 9 10 9 2 7 7 10 5 11 4 12 10 1 9 11 METHODS Diseases of the Colon and Rectum British Journal of Surgery In this review, mechanical bowel preparation will be defined as an oral preparation given prior to surgery to clear faecal material from the bowel lumen. There are a number of different preparations available including polyethylene glycol, mannitol and sodium picosulphate. Rectal enemas may also be administered before low anterior resections to ensure that the rectum is empty. Elective colorectal surgery is defined as any surgery undertaken on a planned basis for any condition of the colon or rectum requiring bowel resection and primary anastomosis. This will include colorectal carcinoma and inflammatory bowel disease. 10 11 13 14 5 Table I Table I RCTs examining MBP  Zmora 2003 Fa-Si-Oen 2005 Ram 2005 Bucher 2005 Miettinen 2000 No. of patients included 415 250 329 153 267  No. of patients excluded 35 0 Not given 0 12  No. of pt (MBP/no MBP) 187/193 125/125 164/165 78/75 138/129  Mean age (MBP/no MBP) 68/68 68/70 (median) 68/68 63/63 61/64  Cancer % (MBP/no MBP) 78/78 90/92 75/88 32/28 46/55  L colon surgery % (MBP/no MBP) 68/72 48/58 89/85 100/100 45/47  Type of prep Polyethylene glycol Polyethylene glycol Sodium phosphate Polyethylene glycol Polyethylene glycol  Antibiotic Yes Yes Yes Yes Yes  Same length of prophylaxis No Yes Yes No Yes  Rectal enema Yes No No Yes No  Anastomosis % (stapled / handsewn) Not given 7/93 (MBP) 8/92 (no MBP) 94/6 (MBP) 98/2 (no MBP) Not given 60/30 (MBP) 62/28 (no MBP)  Surgeon/trainee % Not given 42/59 (MBP) 50/50 (no MBP) 37/63 (MBP) 32/68 (no MBP) Not given Not given  Anastomotic leak % (MBP / no MBP) 3.7/2.1 (NS) 5.6/4.8 (NS) 0.6/1.2 (NS) 6/1 (NS) 4/2 (NS)  Wound infection % (MBP / no MBP) 6.4/5.7 (NS) 7.2/5.6 (NS) 9.8/6.1 (NS) 13/4 (NS) 4/2 (NS)  Intra-abdominal abscess % (MBP / no MBP) 1.1/1 (NS) Not given 0.6/0.6 (NS) 1/3 (NS) 2/3 (NS) NS = not significant 1 2 7 9 15 DISCUSSION 1 2 7 9 15 7 et al 9 There were conflicting results in the non-randomised studies with some showing an increased rate of infection and others reporting no difference in infection rates between the groups. 1 2 8 15 1 2 8 et al 15 et al 8 1 15 et al 15 et al 1 15 et al 1 5 10 11 13 14 10 11 13 14 et al 10 There was no difference found in the rate of post-operative infectious complications between the two groups. The rate of diarrhoea post-operatively was significantly more common in the group receiving MBP but this is of little clinical significance, as many patients will experience an increased stool frequency once the bowels become active. The authors acknowledge that separating the role of MBP in post-operative infection rate is difficult and ideally all other measures should be constant. They also note that the study is underpowered to detect a 5% difference in infection rate. et al 5 et al 14 et al 13 et al 11 10 11 13 9 et al 16 One hundred and thirty six patients who underwent elective left-sided colorectal procedures for non-obstructive large bowel pathologies were identified using the hospital computer system. Coding errors may mean that some eligible patients were excluded from the analysis. This, along with the lack of randomisation, would introduce significant bias. No statistical difference was found between the two groups for all infectious complications and mortality. The authors recognise the limitations of their results and do not recommend any changes in practice but do suggest that a prospective randomised trial should be performed to demonstrate the impact of MBP on morbidity and mortality in patients undergoing elective colorectal surgery. et al 17 et al 4 CONCLUSION 10 11 13 14 9 1 15 1