Methods

Randomisation was performed centrally via an interactive voice randomisation system.

Single‐blinded: the surgeon was blinded to the randomisation process and the preparation status of all patients.

Withdrawal/dropout:7 patients were excluded (5 missing consent form, 1 refusal of surgical treatment, 1 loss of follow‐up).

Follow‐up: 30 days postoperative.

Participants

Inclusion criteria: all the patients aged 18 years or old with rectal cancer who underwent laparoscopic or open elective rectal resection with mesorectal excision and sphincter preservation.

Exclusion criteria: very low tumours (abdominal perineal excision): metastasis in the liver or lungs; T4 rectal cancer; synchronous adenocarcinoma; and/or gastrointestinal disease, refusing extensive colonic surgery.

Diseases: rectal cancer.

Number of participants: 178 (102 male; 76 female).

Age: 54 ‐ 71 years.

Location of study: 8 french hospitals (Paris (2 hospitals), Bordeaux, Montpellier, Marseilles, Toulouse, Boulogne Billancourt, Clermont‐Ferrand).

Antibiotics: 500 mg of metronidazole + 1 g of ceftriaxone at anaesthetic induction and were continued every 2 hours during the surgical procedure.

Interventions

Group A ‐ MBP (n = 89): oral laxatives and retrograde enemas ‐ senna solution. After the preparation diet was confined to clear fluids.

Group B ‐ no MBP (n = 89): no preoperative dietary restrictions.

Outcomes

Anastomotic leakage: Group A = 8, Group B ‐ 17

‐ Asymptomatic anastomotic leakage: Group A = 2, Group B = 3;

‐ Clinical anastomotic leakage: Group A = 6, Group B = 14.

Wound abscess: Group A = 3, Group B = 1.

Pelvic abscess: Group A = 1, Group B = 7.

Peritonitis: Group A = 2, Group B = 6.

Reoperation: Group A = 12, Group B = 5.

Infectious abdominal complications: Group A = 15, Group B = 34.

Infectious extra abdominal complications: Group A = 1, Group B = 1.

Non infectious abdominal complications: Group A = 7, Group B = 14.

Non infectious extra abdominal complications: Group A = 5, Group B = 1.

Necessity to rectal stump washout intra operatively for pool preparation: Group A = 43, Group B = 47.

Intraoperative faecal spillage: Group A = 2, Group B = 7.

Notes

A multicenter study: 8 participating national (France) hospitals.

Included patients with preoperative radiotherapy and chemiotherapy.

Intention‐to‐treat analysis was performed.

The sample size was calculated (n = 90 participants, in each group).

Temporaly ileostomy: Group A = 71, Group B = 74.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Stated that randomised, but no details provided about randomisation method.

Participants

Inclusion criteria: participants undergoing elective colorectal surgery.

Exclusion criteria: no details.

Diseases: colorectal cancer: 164/179; other: 14/179.
Number of participants: 179.

Age: no details.

Location of study: Liverpool, UK.

Interventions

Group A ‐ MPB (n = 86);
Group B ‐ no preparation (n = 93).

Antibiotics: perioperative intravenous (no more details).

Outcomes

Wound infection: Group A = 5, Group B = 7.
Intra‐abdominal sepsis: Group A = 8, Group B = 2.
Anastomic leakage: Group A = 8/67*, Group B = 1/67*.
*only participants in whom bowel continuity was restored.

Notes

Conference proceeding only ‐ never published as article, so results obtained from abstract.
Attempt to contact the authors met with no success.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Unclear risk

B ‐ Unclear

Methods

Randomisation: computer‐generated.
Blinding: not described.
Withdrawal/dropouts: all participants finished the study.
Follow up: 30 days after surgery.

Participants

Inclusion criteria: elective left‐sided colorectal surgery; participants aged 18 years or more; no MBP or antibiotics the week before inclusion.
Exclusion criteria: any patient who could not tolerate the preparation; those who have had the bowel "prepared" for another procedure within the previous week; immunosuppression; human immunodeficiency virus infection; liver cirrhosis; and tumours smaller than 2 cm.
Diseases: colorectal cancer, diverticular disease, Hartmann's reversal, adenoma, endometriosis.
Number: 153 (81 male; 72 female).
Age: 63 years (21‐92 years).
Location: two affiliated departments in Geneva and Yverdon (Switzerland).
Date: 2001‐2003.
Antibiotics: metronidazole and ceftriaxone (continued 24 h after surgery).

Interventions

Group A ‐ MBP (n = 78): 3 litres PEG 12‐16 h before surgery.
Group B ‐ no preparation (n = 75).
Note: one 250 ml saline enema before surgery to participants undergoing anterior resection of the rectum.

Outcomes

Anastomotic leakage: Group A = 5, Group B = 1.
Intra‐abdominal abscess: Group A = 1, Group B = 2.
Peritonitis: Group A = 1, Group B = 0.
Wound infection: Group A = 10, Group B = 3.
Reoperation: Group A = 7, Group B = 2.
Total of complications: Group A = 17, Group B = 6.
Pneumonia: Group A = 6, Group B = 2.
Cardiac: Group A = 7, Group B = 2.
Sepsis: Group A = 1, Group B = 1.
Urinary tract infection: Group A = 4, Group B = 1.
Cerebral embolism: Group A = 1, Group B = 0.
Total of extra‐abdominal complications: Group A = 19, Group B = 8.

Notes

Published data.
Sample size was calculated.
Laparoscopy procedure was included (1/3 of participants).

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Unclear risk

B ‐ Unclear

Methods

Stated that randomised, but no details provided about randomisation method.
Blinding: single‐blind: surgeons were aware of participants' bowel preparation.
Withdrawal/dropout: 31% withdrew (17/186), there were no dropouts.
Follow up: not related.

On a day 7 before surgery, the colorectal anastomosis was checked, in the first half of the series.

Participants

Inclusion criteria: participants admitted for elective colorectal surgery with primary anastomosis.
Exclusion criteria: any participants who could not tolerate the preparation; participants who had the bowel "prepared" for another procedure within previous week.
Diseases: 72% colorectal cancer (133/186); 3% inflammatory bowel disease (6/186); 14% diverticular disease (26/186); 2% other (4/186).
Number: 186 (95 male; 74 female; 17 undetermined).
Age: mean age 64 years.
Location of study: Dublin, Ireland.
Date: October 1988‐September 1992.
Antibiotics: Ceftriaxone 1 g + metronidazole 500 mg intravenously started at induction of anaesthesia. Metronidazole 500 mg: 8 and 16 h, after initial dose.

Interventions

Group A ‐ MBP group (n = 82): sodium picosulphate 10 mg, the day before surgery (dose in morning and afternoon).
Group B ‐ normal diet and no other bowel preparation (n = 87).

Outcomes

Death: Group A =2; Group B = 0.
Cardiorespiratory complications: Group A = 8; Group B = 9.
Wound infection: Group A = 4; Group B = 3.
Anastomotic dehiscence: Group A = 3; Group B = 4.
Reoperation: Group A = 2; Group B = 4.

Notes

Representative sample: consecutive participants.
Surgical procedures that were excluded: participants submitted to Hartman's resection (Group A = 5: Group B = 5); defunctioning colostomy (Group A = 0: Group B = 2); abdominal excision of the rectum (Group A = 1: Group B = 2); coloanal anastomosis with colostomy (Group A = 0: Group B = 1); colostomy for rectal polyp (Group A = 1: Group B = 0).
All surgery was performed by one of two consultant surgeons or a senior registrar.
Participants without anastomosis were excluded.

The outcome "Anastomotic leakage" was stratified, by the author:
Left colectomy: Group A = 43; Group B = 51.
Anterior resection: Group A = 39; Group B = 36.
Anastomotic leakage/low anterior resection: Group A = 3/39; Group B = 4/36.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Unclear risk

B ‐ Unclear

Methods

Randomisation: computer‐generated randomisation list; participants were allocated to each intervention by means of numbered sealed envelopes that corresponded to the randomisation list.

Blinding: none.

Withdrawal/dropouts: 77 participants excluded.

Follow up: 24 days (17 ‐ 34 days).

Participants

Inclusion criteria: indication for elective colorectal surgery with primary anastomosis.

Exclusion criteria: acute laparotomy; laparoscopic colorectal surgery; contraindication for MBP; ileal stoma; younger than 18 years.

Diseases: colorectal cancer, inflammatory bowel disease, radiation induced stenosis, endometriosis, correction of Hartmann's.
Number: 1354 (682 male, 672 female).

Age: mean age 67 years.

Location of study: 13 participating hospitals in the Netherlands.

Date: April 1998‐February 2004.

Antibiotics: according to the guideline of each hospital: cefuroxime + metronidazole, cefazolin + metronidazole, cefamandole + metronidazole, gentamycin + metronidazole, amoxicillin + clavulanate, and others.

Interventions

Group A ‐ MBP (n = 670): PEG + bisacodyl (11 hospitals) or sodium phosphate solution (2 hospitals); fluid diet on the day before surgery.
Group B ‐ normal meals (n = 684).

Outcomes

Anastomotic leakage: Group A = 32, Group B = 37.
Wound infection: Group A = 90, Group B = 96.
Fascia dehiscence: Group A = 19, Group B = 16.
Urinary tract infection: Group A = 71, Group B = 70.
Pneumonia: Group A = 39, Group B = 51.
Intra‐abdominal abscess: Group A = 15, Group B = 32.
Secondary intervention (reoperation): Group A = 58, Group B = 58.
Mortality: Group A = 20, Group B = 26.

Outcomes measured in days (postoperatives):
Hospital stay: Group A = 10, Group B = 10.
Resumption of normal diet: Group A = 6, Group B = 6.

No postoperative complications: Group A = 462, Group B = 452.

Notes

A multicenter study.
Sample size was calculated.
By chance, more participants who smoked and had inflammatory bowel disease were allocated to MBP group.
X² test or Fischer's exact test to compare complication rates between groups; Mann‐Whitney test to compare continuous or graded outcomes.
Univariate analysis to asses the risk of anastomotic leakage. Multivariated logistic regression to test the risk factors simultaneously for any association with anastomotic failure. Multivariate analysis stowed that ASA classification, type of anastomosis and blood loss during operation were independent risk factors for anastomotic leakage.

In 2010 subgroup analysis is published by van't Sant the authors of this review made the calculus:

Colonic surgery (n = 905): Group A = 434; Group B = 471.

‐ Anastomotic leakage: Group A = 14; Group B = 23.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Central trial office of randomisation, computer generated.
Concealment OK.
Blinding: not described.
Withdrawal/dropout: no exclusions.
Follow up: 3 months.

Participants

Inclusion criteria: elective colon surgery.
Exclusion criteria: previous radiotherapy and/or chemotherapy; idiopathic inflammatory bowel disease; obstructive tumours; emergency laparotomy; MBP one week before the surgery; ileocaecal resections and resections below the peritoneal reflection.
Diseases: recurrent diverticular disease, colon malignancy, other.
Number: 250 (114 male; 136 female).
Age: 27.7‐89.0 years.
Location: 5 centres in the Netherlands (4) and Belgium (1).
Date: 1 October 1998‐1 October 2002.
Antibiotics: cefazolin (2 g) + metronidazole (1.5 g) or gentamicin (240 mg) + metronidazole (1.5 g), 30 minutes before surgery.

Interventions

Group A ‐ MBP (n = 125): 4 litres of PEG.
Group B ‐ normal meal up to ten hours before surgery (n = 125).

Outcomes

Anastomotic leakage: Group A = 7, Group B = 6;
Wound infection: Group A = 9, Group B = 7.

Reoperation: Group A = 13, Group B = 11.

Notes

Primary data.
Multicentre study.
Sample size was calculated.
All participants were included as intention to treat.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: no details.
Blinding: double‐blind (orange juice for the control group; no details about blinding the surgeons).
Withdrawals/dropouts: no withdrawals or dropouts.

Follow up: 30 days after surgery.

Participants

Inclusion criteria: participants admitted for elective colorectal surgery with primary anastomosis.
Exclusion criteria: no exclusions.
Diseases (Group A/B): colorectal cancer (22/21); diverticular disease (5/6); inflammatory bowel disease (2/3); ischemics colitis (1/0).
Number: 60 (33 male; 27 female).
Age: 31‐82 years.
Location: Porto Alegre, RS, Brazil.
Date: 1992‐1993.

Antibiotics: metronidazole + gentamicin 1 h before surgery, and then for 48 h.

Interventions

Group A ‐ MBP (n = 30): 500 ml mannitol 20% + 500 ml orange juice.
Group B ‐ orange juice (n = 30).

Outcomes

Wound infection: Group A = 1; Group B = 2.
Peritonitis: Group A = 2; Group B = 1.
Extra‐abdominal complications (non‐infectious):

‐Mechanical obstruction: Group A = 0; Group B = 1.

‐Dehiscence of wall suture: Group A = 0; Group B = 1.

‐Pulmonary embolism: Group A = 1; Group B = 0.

Extra‐abdominal complications (infections):

‐Pneumonia: Group A = 1; Group B = 1.

‐Urinary infection: Group A = 1; Group B = 2.

Notes

The sample size was calculated, but no details given.
Included participants without anastomosis.
Recurrence was not mentioned.
No deaths in this trial.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: Central randomisation; random numbers.
Blinding: none.

Participants

Inclusion criteria: participants undergoing elective open surgery for cancer, adenoma or diverticular disease of the rectum, involving an anastomosis; aged between 18‐85 years with an ASA grade of I, II or III.
Exclusion criteria: laparoscopic surgery; procedures involving a stoma; ASA scope IV and a life expectancy of less than 6 months.
Diseases: cancer, adenomas, diverticular disease.
Number: 44.
Date: January 1999‐March 2005.
Antibiotics: oral sulphamethoxazole‐trimethoprim + metronidazole, cephalosporin + metronidazole, or doxycycline + metronidazole.

Interventions

Group A ‐ MBP (n = 27): PEG or sodium phosphate.
Group B ‐ no preparation (n = 17).

Outcomes

Anastomotic dehiscence: Group A = 3, Group B = 0.
Wound infection: Group A = 4, Group B = 1.
General infections: Group A = 5, Group B = 1.

Notes

A multicenter study.
Surgeons in this study were all specialists in colorectal surgery.
Intention‐to‐treat analysis.
This is a group of participants, who were first included in Jung 2007, but later excluded due to rectal surgery. These data are unpublished thus far.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: central randomisation; random numbers.
Blinding: none.
Withdrawal/dropout: 14 (Group A), 12 (Group B): lost to follow up and data not submitted.
Follow up: 30 days after surgery.

Participants

Inclusion criteria: participants undergoing elective open surgery for cancer, adenoma or diverticular disease of the colon, involving an anastomosis; aged between 18‐85 years with an ASA grade of I, II or III.
Exclusion criteria (162 excluded): laparoscopic surgery; procedures involving a stoma; ASA scope IV and a life expectancy of less than 6 months.
Diseases: cancer, adenomas, diverticular disease.
Number: 1343 (623 male; 720 female)
Age: 69 years (28‐86 years).
Location of study: 1 German and 20 Swedish colorectal units.
Date: January 1999‐March 2005.
Antibiotics: oral sulphamethoxazole‐trimethoprim + metronidazole (46%); cephalosporin + metronidazole (33%); doxycycline + metronidazole (14%).

Interventions

Group A ‐ MBP (n = 686): PEG or sodium phosphate.
Group B ‐ no preparation (n = 657).

Outcomes

Anastomotic dehiscence: Group A = 13, Group B = 17.
Wound infection: Group A = 54, Group B = 42.
Deep abscess: Group A = 5, Group B = 11.

Reoperation: Group A = 30, Group B = 35.
Wound disruption: Group A = 10, Group B = 13.
Cardiovascular complications: Group A = 35, Group B = 30.
General infections: Group A = 54, Group B = 45.
Surgical site: Group A = 103, Group B = 106.
Total number of complications: Group A = 192, Group B = 181.

Notes

A multicenter study.
The groups were well matched with regard to age, sex and diagnosis.
Surgeons in this study were all specialists in colorectal surgery.
Intention‐to‐treat analysis.
The sample size was calculated.
The mean hospital stay was 9 days (7‐14 days).
Extra data after stratification has been obtained in a personal communication with the author.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: sealed envelopes at the time of the assignment of the surgical date.

Blinding: not described.

Withdrawal/Dropout: not described.

Duration of follow‐up: not related.

Participants

Inclusion criteria: all the consecutives electives surgeries with colonic anastomosis (ileocolonic, colonic, colorectal), including colonic transit reestablishment.

Exclusion criteria: patients with immediately postoperative death without relation an intraabdominal sepsis or anastomotic leakage; patients whom refused to be operated without mechanical bowel preparation; patients submitted to bowel preparation for colonoscopy within 4 days prior to surgery.

Diseases: benign or malignant colorectal pathology.

Number of participants: 129 (77 male; 52 female).

Age: 15 ‐ 85 years.

Location of study: Hospital General de Agudos and private clinic, Lanus, province of Buenos Aires.

Time os study: 2005 (March) ‐ 2006 (September).

Antibiotics: ciprofloxacin 500 mg + metronidazole 500 mg.

Interventions

Group A ‐ MBP (n = 64): upon availability dibasic‐monobasic sodium phosphate or polyethylene glycol.

Group B ‐ no MBP (n = 65).

Outcomes

Anastomotic leakage: Group A = 3 (in 53 patients), Group B = 9 (in 59 patients)

‐ Leakage in anastomosis intraperitoneal: Group A = 2 (in 43 patients), Group B = 5 (in 42 patients);

‐ Leakage in anastomosis extraperitoneal: Group A = 1 (in 10 patients), Group B = 4 (in 17 patients).

Reoperation: Group A = 3, Group B = 5

‐ Reoperation for leakage: Group A = 3, Group B = 4.

Mortality: Group A = 1, Group B = 2.

Wound infection: Group A = 10, Group B = 10.

Peritonits: Group A = 3, Group B = 4.

Intraabdominal abscess: Group A = 1, Group B = 0.

Notes

Sample size was not calculated.

Excluded patients without anastomosis in the outcome "Anastomotic leakage".

Patients without anastomosis: Group A = 6 abdominoperineal amputation, 5 Hartmann's procedure; Group B = 4 abdominoperineal amputation, 2 Hartmann's procedure.

Anastomosis and dehiscence:

‐ Right: Group A (25) = 1, Group B (21) = 2;

‐ Left: Group A (18) = 1, Group B (21) = 2;

‐ Low: Group A (10) = 1, Group B (17) = 4.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: sealed envelopes; consecutive adult participants.
Blinding: not described.
Withdrawal/dropout: all participants completed the study.
Follow up: 1‐2 months after surgery.

Participants

Inclusion criteria: all consecutive adults admitted for elective colorectal surgery.
Exclusion criteria: participants who have had bowel preparation for colonoscopy one week before surgery (n = 5); participants who were unable to drink PEG‐ELS (n = 2); participants not requiring opening of the bowel (n = 4); patient who refused to be randomised (n = 1).

Disease: colorectal cancer (134); benign tumours (24); inflammatory bowel disease (32); diverticular disease (58); other (19).

Number: 267 (130 male; 137 female).

Age: 16‐97 years.

Location: Kuopio + Oulu, Finland.

Date: 1994‐1996.

Antibiotics: ceftriaxone 2 g + metronidazole 1 g at the induction of anaesthesia.

Interventions

Group A ‐ MBP (n = 138): PEG electrolyte solution, and no solid food on the preoperative day.
Group B ‐ no preparations and normal diet (n = 129).

Outcomes

Wound infection: Group A = 5; Group B = 3.
Anastomotic leakage: Group A = 5; Group B = 3 (patients without anastomosis were excluded).
Abdominal abscess: Group A = 3; Group B = 4.
Non‐infectious postoperative complication: Group A = 11; Group B = 6.
Reoperation: Group A = 4; Group B = 2: ‐ wound rupture: Group A = 2; Group B = 0;
‐ perforation of the gallbladder: Group A = 1; Group B = 0;
‐ technical anastomotic failure: Group A = 0; Group B = 1;
‐ small bowel occlusions: Group A = 1; Group B = 2.
Extra‐abdominal infections: Group A = 4; Group B = 2.
Postoperative stay (range/days): Group A = 8; Group B = 8.
Operation time (range/min): Group A = 120; Group B = 110.

Notes

Low colonic anastomosis/leakage: Group A = 9/3; Group B = 14/2.
Participants with pre‐existing disease: Group A = 48; Group B = 61.
The differences between the two groups were not significant.
All surgery was carried out by a specialist or a junior surgeon assisted by a specialist.
Excluded participants without anastomosis in the outcome "Anastomotic leakage".
Abdominal abscess: treated conservatively.
No deaths in this trial.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: sealed envelops.

Blinding: not described.

Withdrawal/Dropout: not described.

Follow‐up: 30 days after surgery.

Participants

Inclusion criteria: elective colorectal surgery with primary anastomosis.

Exclusion criteria: colorectal cancer smaller than 2 cm not marked by colonoscopy, those who were found to have an abscess of the tumour, diverticulitis, patients who refused to be randomised.

Diseases: benign and malign colorectal diseases.

Number: 139 (50 male; 89 female).

Age: 68 ‐ 70 years.

Location: Barcelona, Spain

Time: May 2005 ‐ Agost 2007.

Antibiotics:

‐ Oral (single dose 24 hours before the surgery): neomycin + metronidazole;

‐ Parenteral (single dose at the induction of anaesthesia): ceftriaxone + metronidazole.

Interventions

Group A ‐ MBP (n = 69): monobasic sodium phosphate + dibasic sodium phosphate or polyethylene glycol

Group B ‐ no MBP (n = 70): 2 cleansing enemas

‐ the day before the surgery (at 21:00 PM),

‐ 2 hours before the surgery.

Outcomes

Overall anastomotic leakage: Group A = 5; Group B = 4

‐ colorectal anastomosis: Group A = 0 (in 31 patients); Group B = 3 (in 19 patients),

‐ colonic anastomosis: Group A = 5 (in 38 patients); Group B = 1 (in 51 patients).

Mortality: Group A = 2; Group B = 0;

Overall wound infection: Group A = 8; Group B = 4

‐ colorectal surgery: Group A = 3 (in 31 patients); Group B = 0 (in 19 patients),

‐ colonic surgery: Group A = 5 (in 38 patients); Group B = 4 (in 51 patients).

Notes

Sample size was calculated.

Colonic anastomosis: Group A = 38; Group B = 51;

Colorectal anastomosis: Group A = 31; Group B = 19.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: computer‐generated numbers.
Blinding: single‐blinded (participants were followed by an independent observer).
Withdrawal/dropouts: 2 participants excluded perioperatively; 11 at the moment of surgery (diverting stoma, tumour perforation, unresectable tumour).
Follow up: 30 days after surgery.

Participants

Inclusion criteria: all participants scheduled to undergo an elective colon or proximal rectal resection with primary anastomosis by the same surgeon; without intraoperative colonoscopy; had not had endoscopic exploration in the prior week; were 18 years of age or older; had given informed consent.
Exclusion criteria: immunosuppression; preoperative chemoradiotherapy; diverting stoma; perforated and/or obstructing tumour.
Diseases: colorectal cancer (71%), inflammatory bowel disease, other.
Number: 97 (49 male; 48 female).
Age: 54 ‐ 82 years.
Location of study: Hospital Clinico San Carlos, Madrid, Spain.
Date: October 2001‐July 2005.
Antibiotics: 80 mg of gentamicin + 500 mg of metronidazole 30 minutes before surgery and after 8 h postoperatively (3 doses).

Interventions

Group A ‐ MBP (n = 48): 3 litres of oral PEG lavage solution plus conventional enemas over 24 h.
Group B ‐ no preparation (n = 49).
Note: dietary restrictions for both group: 12 h prior to surgery.

Outcomes

Anastomotic failure: Group A = 4, Group B = 2.
Wound infection: Group A = 6, Group B = 6.
Intra‐abdominal sepsis: Group A = 3, Group B = 0.
Mortality: Group A = 3, Group B = 2.

Notes

Sample size was calculated.
No significant differences in demographics were found between the groups.
This trial was presented in abstract form at the 47th Meeting of the Society of Surgery of the Alimentary Tract.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: random numbers.

Blinding: single‐blind (the treating surgeon was blinded).

Withdrawal/Dropout: 41 exclusion after randomisation

‐ Group A: 23 resections of the colon and/or rectum without anastomosis;

‐ Group B: 16 resections, without anastomosis + 2 no resections performed.

Follow‐up: 6 weeks after surgery.

Participants

Inclusion criteria: all patients over the age of 18 years undergoing elective resection of the colon and/or rectum with anastomosis and with or without defunctioning stoma.

Exclusion criteria: patients had undergone mechanical bowel preparation within 2 days of operation date, and patients submitted to laparoscopic procedure.

Diseases: colorectal adenoma and cancer, inflammatory bowel disease, diverticular disease, rectal pathology.

Number: 294 (M:F = Group A: 1: 8, Group B: 1:9).

Age: 21 ‐ 93 years.

Location of study: Perth, Western Australia ‐ Australia.

Date: January 2000 ‐ February 2005.

Antibiotics: ticarcillin disodium and clavulanate potassium (3‐1 g) with induction of anaesthesia or gentamicin (2 mg/kg) + metronidazole (500 mg).

Interventions

Group A ‐ MBP (n = 147): polyethylene glycol

Group B no MBP (n = 147): single sodium phosphate enema 2 ‐ 4 hours before surgery.

Outcomes

Anastomotic leaks: Group A = 3; Group B = 7.

Reoperation: Group A = 0; Group B = 6;

Mortality: Group A = 0; Group B = 1.

Wound infection: Group A = 19; Group B = 21.

Intra‐abdominal abscess: Group A = 1; Group B = 1.

Notes

The sample size was calculated.

There was a significant difference in severity of the leaks: "the presence of a high volume faecal residue is likely to increase the chance of clinically significant anastomotic leak that will require reoperation".

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: participants with even numbers received MBP (Group 1); participants with odd numbers did not receive MBP (Group 2).
Blinding: not related.
Withdrawal/dropouts: no details.
Duration of follow up: not reported.

Participants

Inclusion criteria: adult participants admitted for elective colorectal surgery.
Exclusion criteria: antibiotics for the last 10 days before surgery or if there was evidence of infection; bowel preparation for colonoscopy within 6 days prior to surgery; participants undergoing proctectomy with low rectal anastomosis or surgery for polypoid lesion.
Diseases: malignant disease, irritable bowel disease, diverticulosis.
Number: 329 (201 male; 128 female).
Age: 57 ‐ 80 years.
Location: Division of General Surgery at the Rabin Medical Center, Tel Aviv, Israel.
Date: 1 April 1999 ‐ 31 March 2002.
Antibiotics: 1 h before induction: 500 mg metronidazole + 1 g ceftriaxone; continued for 48 h.

Interventions

Group A ‐ MBP (n = 164): 2.4 g monobasic sodium phosphate + 0.9 g dibasic sodium phosphate + low‐residue diet 1 day before surgery.
Group B ‐ low‐residue diet 1 day before surgery (n = 165).

Outcomes

Mortality: Group A = 2, Group B = 2.
Wound dehiscence: Group A = 3, Group B = 2.
Wound infection: Group A = 16, Group B = 10.
Anastomotic breakdown: Group A = 1, Group B = 2.
Anastomotic bleeding: Group A = not available, Group B = 2.
Abdominal/pelvic collection: Group A = 1, Group B = 1.
Urinary tract infection: Group A = 7, Group B = 5.
Pulmonary complications: Group A = 16, Group B = 9.
Thrombophlebitis: Group A = 15, Group B = 16.
Ileus (temporary postoperative bowel disfunction) : Group A = 14, Group B = 11.
Relaparotomy: Group A = 2, Group B = 2.

Notes

There were more men than women in both groups, but no statistical difference was found between the two groups (sex, age and diagnosis).

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

High risk

C ‐ Inadequate

Methods

Randomisation: participants were allocated by a randomised cards.

Blinding: not described.
Withdrawal/dropouts: 5% (8/157 cases) were withdrawn, but no dropouts.
Follow up: 30 days, or until hospital discharge.

Participants

Inclusion criteria: participants admitted for elective colorectal surgery.
Exclusion criteria: participants that had taken antibiotics for at least 15 days before surgery or if there was evidence of infection or any associated disease requiring antibiotic therapy; and participants in whom the MBP was not feasible.
Group A: 5 participants were excluded: associated infectious disease (2), and failure to achieve full MBP (3).
Group B: 3 participants excluded: an intra‐abdominal foreign body found during the operation (1), and urinary tract infection (2).
Diseases: 43% colorectal cancer (68/157); 34% megacolon (53/157); 6% inflammatory bowel disease (9/157); 3% diverticular disease (5/157); 2% familial adenoma polyposis (3/157); 7% other (11/157).
Number: 157 (72 male; 77 female; 8 undetermined).
Age: 1‐93 years.
Location: Ribeirão Preto, São Paulo ‐ Brazil.
Date: October 1991‐December 1992.
Antibiotics: cephalothin 2 g + metronidazole 1 g intravenously 2 h before induction of anaesthesia. Cephalothine 1 g given at 6 h and 12 h, and metronidazole 500 mg, at 8 h and 16 h after the initial dose.

Interventions

Group A ‐ MBP (n = 72): laxative or enema:
Laxative: (mineral oil, agar and phenolphthalein) 15 ml taken by mouth 3 times a day for 5 days before surgery; mannitol (1 litre as a 10% solution) taken by mouth at the rate of 100 ml per 5 min at 16:00 h on the day before surgery.
Enema: (water 900 ml; glycerin 100 ml) given once a day for 2 days before surgery.
Children: enema of water and glycerin (9:1) twice a day for 2 days before surgery.
Group B ‐ low‐residue diet and no other MBP (n = 77).

Outcomes

Wound infection: Group A = 17; Group B = 9.

Anastomotic dehiscence: Group A = 7; Group B = 4.
Hospital stay: Group A = 2‐34 days; Group B = 0‐90 days.

Reoperation: Group A = 4; Group B = 1.

Notes

Representative sample not described.
Participants' associated medical problems: Group A = 53/75; Group B = 52/78.
Associated medical disease: Group A = 17; Group B = 7.
Most of the participants were operated on by a senior resident (not the consultant).
Included participants without anastomosis.
Reoccurrence was because of leakage.
No death in this trial.
Extra data after stratification had been obtained with personal communication with the author.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: patients were prospectively randomised by individual computer‐generated randomisation into two groups.

Blinding: not described.

Withdrawal/dropout: 62 patients were excluded after randomisation due to the exclusion criteria.

Duration of follow‐up: 30 days postoperative.

Participants

Inclusion criteria: patients undergoing elective colon and rectal surgery with primary anastomosis.

Exclusion criteria: abdominal perineal resection, transanal resection for T1, total mesorectal excision with sphincter saving procedure after neo‐adjuvant therapy for middle or low rectal cancer, R2‐ resection, randomisation in other studies, urgency or emergency procedures, patients who required a diverting stoma proximal to the anastomosis and those who were found to have an abdominal abscess at the time of surgery.

Diseases: colorectal cancer.

Number of participants: 244 (125 male; 110 female).

Age: 60 ‐ 80 years.

Location of study: Oncologic Unit Surgery, San Martino Hospital, Genoa, Italy.

Time of study: 2005 (July) ‐ 2009 (September).

Antibiotics: cephalosporin 2 g + metronidazole 500 mg.

Interventions

Group A ‐ MBP (n = 120): 12 to 16 hours before surgery with polyethylene glycol.

Group B ‐ no MBP (n = 124).

Patients undergoing rectal surgery were given one enema one day before surgery.

Outcomes

Anastomotic leakage: Group A = 7, Group B = 5.

‐ Colon: Group A = 2, Group B = 2.

‐ Rectum: Group A = 5, Group B = 3.

Wound infection: Group A = 11, Group B = 6.

Abdominal abscess: Group A = 6, Group B = 3.

Total of infectious complications: Group A = 24, Group B = 14.

Notes

Surgery localization:

‐ Colon: Group A = 87, Group B = 95.

‐ Rectum (upper): Group A = 33, Group B = 29.

Surgical procedure:

‐ Right colectomy: Group A = 40, Group B = 50.

‐ Transverse colectomy: Group A = 9, Group B = 4.

‐ Left colectomy: Group A = 13, Group B = 26.

‐ Sigmoidectomy: Group A = 25, Group B = 15.

‐ Anterior resection: Group A = 33, Group B = 29.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation, blinding, withdrawal and dropouts: no details.

Follow up: until hospital discharge (not specified).

Participants

Inclusion criteria: participants with colorectal cancer, submitted for elective colorectal surgery.

Exclusion criteria: no details.

Diseases: colorectal cancer.

Number: 47 (21 male, 26 female).

Age: 22‐87 years.

Location of study: Lima, Peru.

Date: October 1999‐January 2001.

Antibiotics: intravenously, against anaerobic and Gram‐negative bacteria, 30 minutes before surgery.

Interventions

Group A ‐ MBP (n = 24): mannitol or PEG electrolyte solution + liquid diet 48 h before surgery.
Group B ‐ liquid diet 48 h before surgery (n = 23).

Outcomes

Wound infection: Group A = 2; Group B = 0.
Anastomotic leakage: Group A = 5; Group B = 0.
Peritonitis: Group A = 3; Group B = 0.

Notes

Length of hospital stay: Group A = 17‐19 days (mean 14); Group B = 6‐15 days (mean 11). Analysed only the complications related with the surgery. Participants without anastomosis (2 in Group A; 3 in Group B).

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Unclear risk

B ‐ Unclear

Methods

It is a subgroup analysis of a prior large multicenter performed by Contant et al.

Randomisation: computer‐generated randomisation list; participants were allocated to each intervention by means of numbered sealed envelopes that corresponded to the randomisation list.

Blinding: none.

Withdrawal/dropouts: not described.

Follow‐up: first outpatients visit after discharge from the hospital which usually occurred after 2 weeks.

Participants

Inclusion criteria: elective low anterior resection with primary anastomosis.

Exclusion criteria: acute laparotomy, laparoscopic colorectal surgery, contraindications for the use of mechanical bowel preparation, an a priori diverting ileostomy, and age less than 18 years old.

Diseases: colorectal cancer, inflammatory bowel disease, other.

Participants: 449 (no details about gender).

Age: not described.

Location of study: Netherlands (13 hospitals).

Date: April 1998 ‐ February 2004.

Antibiotics: according to the guideline of each hospital: cefuroxime + metronidazole, cefazolin + metronidazole, cefamandole + metronidazole, gentamycin + metronidazole, amoxicillin + clavulanate, and others.

Interventions

Group A ‐ Mechanical bowel preparation (n = 236): PEG + bisacodyl (11 hospitals) or sodium phosphate solution (2 hospitals); fluid diet on the day before surgery.
Group B ‐ normal meals (n = 213).

Outcomes

Anastomotic dehiscence: Group A = 18; Group B = 14.

Wound infection: Group A = 39; Group B = 36.

Intraabdominal abscess: Group A = 6; Group B = 9.

Mortality: Group A = 7; Group B = 9.

Urinary tract infection: Group A = 34; Group B = 26.

Pneumonia: Group A = 16; Group B = 20.

Fascia dehiscence: Group A = 7; Group B = 2.

Overall complications: Group A = 92 (39%); Group B = 83 (39%).

Notes

Diverting ileostomy: n = 48 (no stoma = 401).

Stoma: Group A = 27; Group B = 21.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate

Methods

Randomisation: Computer‐generated randomisation.
Blinding: not described.
Withdrawal/dropouts: 29 exclusions (18 abdominoperineal resection, 11 proximal stoma)
Follow up: 30 days after surgery.

Participants

Inclusion criteria: participants undergoing elective colon and rectal surgery with primary anastomosis.
Exclusion criteria: participants with tumours smaller than 2 cm, who required a diverting stoma proximal to the anastomosis, and those who were found to have an abdominal abscess at the time of surgery.
Diseases: carcinoma of the colon and rectum, diverticular disease, Hartmann's procedure, benign polyp, inflammatory bowel disease, other.
Number: 380 (197 male, 183 female).
Age: 68 yeas (22‐92 years).
Location: 2 university‐affiliated departments of surgery ‐ Tel Aviv and Haifa, Israel.
Date: July 1997‐July 2000
Antibiotics: 3 doses of neomycin + erythromycin + perioperative broad‐spectrum IV antibiotics.

Interventions

Group A ‐ MBP (n = 187): 1 gallon PEG 12‐16 h before surgery.
Group B ‐ no preparation (n = 193).
Note: participants in either group who were planned for rectal surgery were given one phosphate enema on the day of surgery.

Outcomes

Wound infection: Group A = 12, Group B = 11.
Anastomotic leakage: Group A = 7, Group B = 4.
Abdominal abscess: Group A = 2, Group B = 2.
Mortality: Group A = 3, Group B = 3.

Overall non surgical complications: Group A = 53, Group B = 54.

Notes

Extra data after stratification had been obtained with personal communication with the author.

Risk of bias

Bias

Authors' judgement

Support for judgement

Allocation concealment (selection bias)

Low risk

A ‐ Adequate