Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 

 Table of Contents  
Year : 2017  |  Volume : 5  |  Issue : 3  |  Page : 101-105

Mechanical bowel preparation versus no bowel preparation in open colorectal surgery: A prospective study

1 Department of General Surgery, Indira Gandhi Medical College and Hospital, Shimla, Himachal Pradesh, India
2 Department of Microbiology, Indira Gandhi Medical College and Hospital, Shimla, Himachal Pradesh, India

Date of Web Publication6-Nov-2017

Correspondence Address:
Tushar Patial
Department of Surgery, Indira Gandhi Medical College, Shimla - 171 001, Himachal Pradesh
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ssj.ssj_17_17

Rights and Permissions

Background: Colorectal surgery has always been a challenge for surgeons due to a large number of bacteria present in this area. Some of these bacteria may cause wound infection, anastomotic leak or frank sepsis. Mechanical bowel preparation (MBP) has been one of the many practices which aim to mitigate these complications. However, the use of MBP has been controversial for sometimes. We performed a prospective study to investigate the outcomes of colorectal surgery with or without MBP.
Materials and Methods: This prospective study was conducted in the Department of Surgery, IGMC, Shimla from July 1, 2014 to June 30, 2015 included forty patients admitted in an emergency, or for elective open colorectal surgery. All patients who were scheduled to undergo primary resection and anastomosis of the colon and upper rectum were eligible for inclusion in the study.
Results: Complications in the form of surgical site infection, wound hematoma, and enterocutaneous fistula were present in both groups. However the value of P = 0.204 in either group indicated that statistically, there was no difference between results of two groups. The average duration of stay in the no bowel preparation group was 13.42 days, and in the MBP group was 11.5 days.
Conclusion: This study suggests that MBP is not necessarily essential for safe colorectal surgery.

Keywords: Anastomotic leakage, colorectal surgery, mechanical bowel preparation

How to cite this article:
Patial T, Sharma VK, Mokta K, Jaswal K S, Thakur V, Vijhay Ganesun N K. Mechanical bowel preparation versus no bowel preparation in open colorectal surgery: A prospective study. Saudi Surg J 2017;5:101-5

How to cite this URL:
Patial T, Sharma VK, Mokta K, Jaswal K S, Thakur V, Vijhay Ganesun N K. Mechanical bowel preparation versus no bowel preparation in open colorectal surgery: A prospective study. Saudi Surg J [serial online] 2017 [cited 2018 Dec 11];5:101-5. Available from: http://www.saudisurgj.org/text.asp?2017/5/3/101/217741

  Introduction Top

Colorectal surgery has always been a challenge for surgeons due to a large number of bacteria present in this area. Some of these bacteria may cause wound infection, anastomotic leak or frank sepsis. Wound infection prolongs wound healing, increases the risk of poor cicatrization, the duration of hospitalization, and subsequent costs of medical care.[1] To mitigate these complications various methods of bowel preparation have been used in the past ranging from dietary restriction, cathartics, enemas, large-volume saline irrigation through a nasogastric tube, to mechanical bowel preparation (MBP) using agents, such as mannitol, sodium picosulfate, and polyethylene glycol (PEG) based solutions per orally, in conjunction with prophylactic antibiotics.[2]

MBP has been part of a traditional routine in colorectal surgery. The rationale has been that it is supposed to be protective against anastomotic leakage and infectious complications. In many surgical centers, the bowel is thoroughly cleaned before colorectal surgery with the aim to prevent wound infection and anastomotic leakage. The modern practice dated from the 1970s when surgeons such as Cohn, Nichols, and Condon emphasized that mechanical cleaning of the bowel should be an essential part of the preoperative routine.[3]

Current practice

Preoperative preparation for colorectal surgery is most often done with mechanical bowel cleaning and short antibiotic prophylaxis.[3],[4] This practice has, however, come under intense scrutiny. In 1982, Hughes et al.[5] suggested that MBP would please the surgeon, who likes to operate on a clean bowel, and that such measure would not reduce the surgical morbidity or mortality. Since that time, numerous trials and meta-analyses have failed to confer any significant advantage of bowel preparation. Perhaps, the most well-known critical analysis of this fundamental question regarding MBP versus no MBP was addressed by a Cochrane Library Systemic Database Review, first published in 2003 and updated in 2005 and 2011, which not only recommended against the use of bowel preparation but also warned that it leads to worse outcomes.[6] The omission of bowel preparation is also a core principle in most centers for enhanced recovery after surgery packages for colorectal surgery practised throughout Europe and the rest of the world.[7] However, of late, evidence has been mounting to suggest that MBP does have a role in patients undergoing open colorectal surgery.[8],[9]

The study aims to answer this question and clarify if bowel preparation does if fact reduce complications after surgery.

  Materials and Methods Top

This prospective study was conducted in the Department of Surgery, Indira Gandhi Medical College, Shimla, Himachal Pradesh, India from July 1, 2014 to June 30, 2015 included forty patients admitted in emergency, or for elective open colorectal surgery. The patients were assigned into two groups randomly and thus, each group included twenty patients each.

  1. Group A - those not receiving no bowel preparation (NBP)
  2. Group B - those receiving MBP.

Inclusion criteria

All patients who were scheduled to undergo primary resection and anastomosis of the colon and upper rectum were eligible for inclusion in the study, including those of trauma, inflammatory bowel disease and malignancies.

Exclusion criteria

  1. Any known allergy or contraindication to PEG (Group B)
  2. Patients scheduled for a low anterior resection
  3. Poor cardiopulmonary reserve and immunocompromised state
  4. Patients who did not give consent for the study.

Preoperative assessment

In the preoperative assessment, a thorough history and a complete physical examination were done. Preoperative fasting of minimum 12 h was ensured before the operation in all elective cases. Nasogastric tube insertion and aspiration of gastric contents were done in emergency cases.

Patients in Group A (NBP) received a normal meal on the evening before surgery without any preoperative MBP while those of Group B (MBP) received low residue diet for 3 days before surgery and only liquids 1 day before surgery along with bowel preparation in the form of PEG-based drink. One sachet of 137.15 g containing potassium chloride 1.484 g, sodium bicarbonate 3.37 g, PEG 118 g, sodium chloride 2.93 g, and sodium sulfate 11.36 g/137.15 g, was prepared by dissolving one sachet of this PEG-based drink in 2 L of safe drinking water. The solution was consumed over 2 h the night before the surgery. Preoperative prophylactic antibiotics in the form of cefuroxime and metronidazole were given intravenously in both the groups 1 h before the surgery and continued postoperatively.

Postoperative care and follow-up were performed by surgeons and surgical residents unaware of the grouping of the patients. The occurrence of wound infection was documented during the hospital stay and up to 4 weeks postoperatively in the outpatient department.

Postoperative complications in the form of wound infection, anastomotic leakage, disruption of the anastomosis, wound dehiscence, and death (if any), were noted and managed accordingly. Infection was defined as the discharge of pus from the wound, or a clinical suspicion of wound infection based on inflammatory signs such as increased temperature, redness, and tenderness of the wound. When it was deemed necessary to open the infected wound, a separate bacteriological sample was taken of the drained area. This sample was sent to the Department of Microbiology and antibiotics were tailored accordingly. An ultrasound of the abdomen was done in cases of suspicion of intra-abdominal abscess/collection.

Early mobilization was encouraged. The patient was followed up till 1 month postoperatively and wound sepsis, if any, was taken as infection related to surgery.

  Results and Analysis Top

Data from the two groups were entered into Microsoft Excel and analyzed using SPSS Statistical Software (SPSS Inc, Chicago, Illinois, USA). Pearson's Chi-square test was used to compare frequencies between the two treatment groups. For continuous outcome measures, the Student's t-test was used for outcomes with a normal distribution and the Mann–Whitney test for nonparametric outcomes. The value of P = 0.05 was considered statistically significant.

In this study, in the NBP group, the age ranged from 25 to 76 years of age and in the MBP group, the age ranged from 39 to 77 years of age. The mean age was 48.70 years in the NBP group and 54.55 in the MBP group [Table 1].
Table 1: Age distribution

Click here to view

In this study, 52.5% of the patients were females and 47.5% were males. The most common indications for surgery were, carcinoma of the ascending colon (25%) in the NBP group and carcinoma of the ascending colon (30%) in the MBP group [Table 2]. In the NBP group, 8 (40%) cases were either clean contaminated or dirty. Whereas, in the MBP group, all (100%) of cases were cleanly contaminated [Table 3]. The total number of complications were higher in the NBP group (11) versus the MBP group (7) [Table 4]. However, this was statistically not significant (P = 0.204). The average duration of stay in the NBP group was 13.42 days, and in the MBP group was 11.5 days, but was statistically insignificant (P = 0.390) [Table 5]. Although the duration of hospital stay was longer for the NBP group, this too was statistically insignificant. All the cases in the MBP group were performed in the elective setting. However, in the NBP group, 70% (14 cases) of the cases were performed in the elective setting [Table 6].
Table 2: Indications for surgery

Click here to view
Table 3: Degree of contamination in operated patients

Click here to view
Table 4: Postoperative complications in patients undergoing surgery

Click here to view
Table 5: Duration of hospital stay postoperatively

Click here to view
Table 6: Setting of surgery

Click here to view

  Discussion Top

Although MBP is still routine practice in elective open colorectal surgery, the question remains if this procedure achieves the desired reduction in anastomotic leakage and wound infection. Recent evidence although suggests benefit if bowel preparation is combined with oral antibiotics. This may be due to perceived benefits such as easier bowel handling, better ability to palpate small tumors and polyps, facilitation of on-table endoscopy and eradiation of harmful bacteria.[10]

It is believed that the concentration of the micro-organisms in the intra-operative remaining fecal residue does not decrease with the various forms of MBP.[11] Bowel preparation changes the physical characteristics of feces, which, by some authors is a protective factor against the pressure of the fecal bulk against the fresh anastomosis.[12],[13] Others consider the newly formed soluble formless manageable and therefore more dangerous due to easy leakage through the fresh anastomosis, leading to fecal spill and subsequent peritonitis.[14] MBP disturbs the endoluminal bowel homoeostasis. The mucosa is known to be dependent on endoluminal fuel delivery. The fecal butyrates and other short chain fatty acids are essential for cellular proliferation of colonic mucosa.[15] MBP leads to a depletion of these basic fuels, with suboptimal preoperative bowel tissue as a result. This may increase the chance of postoperative anastomotic necrosis and susceptibility for postoperative infection.[2] For those using MBP to clean the bowel, it seems logical that to have maximal effect on colonic bacterial concentration and thus, a beneficial effect on postoperative infectious complications, the use of nonabsorbable antibiotics should follow MBP.[11] Nichols and Condon [3] showed that neomycin and erythromycin given the day before surgery significantly reduced fecal aerobic and anaerobic bacteria. The same group also found that mechanical bowel cleansing had the effect of increasing the concentration of intraluminal erythromycin.

In 1992, Mansvelt et al.[10] reported on 189 patients undergoing elective colorectal surgery with just one or two enema's preoperatively. They reported a mortality rate of 1.6%, 0% anastomotic leak, and 2.6% wound infection rate.

van Geldere et al.[15] presented a series of 250 consecutive patients undergoing elective colorectal surgery without MBP with an anastomotic failure rate of 1.2%. They suggested that feces does not harm the healing process since the colonic mucosa derives most of its energy supply from the colonic lumen by bacterial metabolites of fermentable fiber, mainly short-chain fatty acids like butyrate.

The results of Mansvelt et al.[10] and van Geldere et al.[15] done without bowel preparation are remarkable, but they are achieved by a single experienced colorectal surgeon. This differs from daily surgical practice, especially in training centers like ours, where teams of surgeons are responsible for the care of patients.

A meta-analysis by Güenaga et al.,[6] for the Cochrane database showed a higher incidence of wound infections in the group receiving MBP. There was also a higher anastomotic leakage rate in the group receiving MBP.

In 2014, Brown et al.[16] assessed the effect of bowel preparation on colonic tissue and discovered a decrease in cellular proliferation after MBP. The cause of this impairment was hypothesized that MBP leads to an alteration in butyrate transport. Butyrate and other short-chain fatty acids are the primary sources of energy of the colonocyte. In addition, butyrate may favor an adaptive response to surgical interventions, such as anastomotic healing. Protein, monocarboxylate transporter (MCT)-1, is responsible for the transport of butyrate, propionate, and acetate in order of preference. This study found a reduced level of MCT-1 after bowel preparation, indicating that MBP results in a disruption of homoeostasis at the cellular level.

In 2015, Elnahas et al.[9] suggested that MBP omission was associated with a higher rate of 30-day anastomotic leaks. They were unable to ascribe any specific reason for the same but acknowledged that further research was required to recommend omission or inclusion of MBP as standard practice in colorectal surgery. Furthermore, in 2015, Kiran et al.[8] published an analysis of 8442 patients, concerning the impact of MBP with antibiotics on surgical outcomes, in particular, anastomotic leak, surgical site infection, and ileus. They found that usage of this combination reduced the above-mentioned complications by nearly half. They found that MBP with antibiotics was superior to no MBP.

The study confirms the results obtained from the few other series on open colorectal surgery without MBP.

In this study, the total anastomotic leakage rate was 2.5%, with an anastomotic leak in the NBP group being 5%. This compares favorably with studies by Elnahas et al.,[9] and Kiran et al.[8] of previously published studies of colorectal surgery, where the anastomotic leakage rate was higher in the group not receiving bowel preparation. This study also compares favorably to reports where MBP was performed such as those by Miettinen et al.[17] and Zmora et al.[14] The reported leakage rate of the latter varies considerably from 0 to 30%, but averages 5%.[9]

The wound infection rate in this study was 22.5%, with 20% infection rate in the NBP group. This is similar to the rate seen by Hughes et al.,[5] Baker et al.,[13] This could likely be due to the presence of comorbidities and operating on the patient in the emergency setting.

One patient died of sepsis, and the mortality rate of 2.5% is in keeping with that of other studies, where total mortality ranges from 0 to 16%, with an average of approximately 5%. A 36-year-old male patient who presented to the emergency with blunt trauma abdomen– with the gangrenous gut ileocolic region with multiple rib fractures complicated by hemothorax. The patient's demise on the postoperative day 6, was likely due to the presence of multiple injuries and systemic inflammatory response syndrome.

There was one anastomotic leak, which occurred in the NBP group. The total anastomotic leak rate was 2.5%, which is in accordance Miettinen et al.,[17] Zmora et al.,[14] Elnahas et al.,[9] and Kiran et al.[8] This rate is much lower than those reported by Hughes et al.[5] in patients who underwent bowel preparation. Other risk factors, such as associated peritonitis, the presence of a comorbidity in the form of an irreducible hernia, inexperience on the part of the surgeon and delayed presentation may have contributed to the failure of this anastomoses.[18] An empty bowel may theoretically render anastomotic leakage less dangerous and facilitate its management if it occurs. However, anastomotic leakage usually occurs after seven to 8 days, by which time the previously prepared bowel is already loaded, regardless of the regimen of early oral feeding or traditional bowel confinement.[15]

Other endpoints like wound infection also favored the no-preparation groups. In this study, selection bias was minimized by including only colon surgery with an intraperitoneal anastomosis. Low anterior resections were excluded because previous studies demonstrate that the anastomotic leakage rate in these low anastomoses is higher due to poor anastomosis vascularization and several other surgical aspects.[2]

It has long been thought that cleaning the bowel preoperatively reduced the amount of bacteriological species. However while reducing fecal mass, preoperative bowel preparation does not alter the concentration of fecal organisms intraluminally.[11] Moreover, MBP reduces solid stool to less manageable liquefied debris which can more readily protrude the fresh anastomosis.[14],[18],[19]

  Conclusion Top

This study suggests that patients who undergo MBP before colorectal surgery, have a slightly higher rate of wound infection but have similar rates of the anastomotic leak when compared to patients not undergoing MBP. Although the results of this study are for the omission of MBP, our study was limited by a small sample size, varied distribution of diagnosis and lack of a quantitative bacterial count. We opine that MBP is not necessarily essential for safe colorectal surgery. Healing of the loaded bowel is more than feasible. More powerful randomized clinical trials and meta-analysis are needed to accept or deny the role of bowel preparation in colorectal surgery.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Bornside GH, Cohn I Jr. Intestinal antisepsis. Stability of fecal flora during mechanical cleansing. Gastroenterology 1969;57:569-73.  Back to cited text no. 1
Solla JA, Rothenberger DA. Preoperative bowel preparation. A survey of colon and rectal surgeons. Dis Colon Rectum 1990;33:154-9.  Back to cited text no. 2
Nichols RL, Condon RE. Preoperative preparation of the colon. Surg Gynecol Obstet 1971;132:323-37.  Back to cited text no. 3
Zmora O, Pikarsky AJ, Wexner SD. Bowel preparation for colorectal surgery. Dis Colon Rectum 2001;44:1537-49.  Back to cited text no. 4
Hughes ES, McDermott FT, Polglase AL, Johnson WR, Pihl EA. Sepsis and asepsis in large bowel cancer surgery. World J Surg 1982;6:160-5.  Back to cited text no. 5
Güenaga KF, Matos D, Wille-Jørgensen P. Mechanical bowel preparation for elective colorectal surgery. Cochrane Database of Systematic Reviews 2011: CD001544. DOI: 10.1002/14651858.CD001544.pub4.  Back to cited text no. 6
Rawlinson A, Kang P, Evans J, Khanna A. A systematic review of enhanced recovery protocols in colorectal surgery. Ann R Coll Surg Engl 2011;93:583-8.  Back to cited text no. 7
Kiran RP, Murray AC, Chiuzan C, Estrada D, Forde K. Combined preoperative mechanical bowel preparation with oral antibiotics significantly reduces surgical site infection, anastomotic leak, and ileus after colorectal surgery. Ann Surg 2015;262:416-25.  Back to cited text no. 8
Elnahas A, Urbach D, Lebovic G, Mamdani M, Okrainec A, Quereshy FA, et al. The effect of mechanical bowel preparation on anastomotic leaks in elective left-sided colorectal resections. Am J Surg 2015;210:793-8.  Back to cited text no. 9
Mansvelt B, Arrigo E, Passelecq E, Gavelli A, Harb J, Huguet C. Minimal intestinal preparation before colectomy for cancer. Experience of 189 cases. Ann Chir 1992;46:592-5.  Back to cited text no. 10
Miller TA. Modern Surgical Care: Physiologic Foundations and Clinical Applications. New York: CRC Press; 2006.  Back to cited text no. 11
Mahabier C. Pre- and Intraoperative Gut Irrigation and Antibiotics in Colorectal Surgery: A Clinical and Experimental Study; 1989.  Back to cited text no. 12
Baker LW, Thomson SR, Chadwick SJ. Colon wound management and prograde colonic lavage in large bowel trauma. Br J Surg 1990;77:872-6.  Back to cited text no. 13
Zmora O, Mahajna A, Bar-Zakai B, Rosin D, Hershko D, Shabtai M, et al. Colon and rectal surgery without mechanical bowel preparation: A randomized prospective trial. Ann Surg 2003;237:363-7.  Back to cited text no. 14
van Geldere D, Fa-Si-Oen P, Noach LA, Rietra PJ, Peterse JL, Boom RP. Complications after colorectal surgery without mechanical bowel preparation. Am Coll Surg 2002;194:40-7.  Back to cited text no. 15
Brown SR, Ali MS, Williams M, Swisher JP, Rice WV, Coviello LC, et al. Cellular changes of the colon after mechanical bowel preparation. J Surg Res 2015;193:619-25.  Back to cited text no. 16
Miettinen RP, Laitinen ST, Mäkelä JT, Pääkkönen ME. Bowel preparation with oral polyethylene glycol electrolyte solution vs. no preparation in elective open colorectal surgery: Prospective, randomized study. Dis Colon Rectum 2000;43:669-75.  Back to cited text no. 17
Cameron JL, Cameron AM. Current Surgical Therapy: London: Elsevier Health Sciences; 2013.  Back to cited text no. 18
Fa-Si-Oen PR, Verwaest C, Buitenweg J, Putter H, de Waard JW, van de Velde CJ, et al. Effect of mechanical bowel preparation with polyethyleneglycol on bacterial contamination and wound infection in patients undergoing elective open colon surgery. Clin Microbiol Infect 2005;11:158-60.  Back to cited text no. 19


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Materials and Me...
Results and Analysis
Article Tables

 Article Access Statistics
    PDF Downloaded144    
    Comments [Add]    

Recommend this journal