Bowel preparation in colorectal surgery: back to the future?

The Impact of Mechanical Bowel Preparation and Oral Antibiotics in Colorectal Cancer Surgery (MECCA Study): A Prospective Randomized Clinical Trial

Background: Colorectal cancer surgery has been associated with surgical site infections (SSIs), leading to an increase in postoperative morbidity, length of stay and total cost. The aim of the present randomized study was to investigate the relationship between the preoperative administration of oral antibiotic therapy and SSI rate, as well as other postoperative outcomes in patients undergoing colorectal cancer surgery. Material and Methods: Patients who underwent colorectal cancer surgery in a university surgical department were included in the present study. Patients were randomized into two groups using the "block randomization" method. The intervention group received three doses of 400 mg rifaximin and one dose of 500 mg metronidazole per os, as well as mechanical bowel preparation the day before surgery. The control group underwent only mechanical bowel preparation the day before surgery. The study has been registered in ClinicalTrials.gov (NCT03563586). Results: Two hundred and five patients were finally included in the present study, 97 of whom received preoperative antibiotic therapy per os (intervention group). Patients of this group demonstrated a significantly lower SSI rate compared with patients who did not receive preoperative antibiotic therapy (7% vs. 16%, p = 0.049). However, preoperative antibiotic administration was not correlated with any other postoperative outcome (anastomotic leak, overall complications, readmissions, length of stay). Conclusions: Preoperative antibiotic therapy in combination with mechanical bowel preparation seemed to be correlated with a lower SSI rate after colorectal cancer surgery.

The role of preoperative mechanical bowel preparation and oral antibiotics in prevention of anastomotic leakage following restorative resection for primary rectal cancer - a systematic review and meta-analysis

PURPOSE

Anastomotic leakage after colorectal cancer resection is a feared postoperative complication seen among up till 10-20% of patients, with a higher risk following rectal resection than colon resection. Recent studies suggest that the combined use of preoperative mechanical bowel preparation and oral antibiotics may have a preventive effect on anastomotic leakage. This systematic review aims to explore the association between preoperative mechanical bowel preparation combined with oral antibiotics and the risk of anastomotic leakage following restorative resection for primary rectal cancer.

METHODS

Three databases were systematically searched in February 2022. Studies reporting anastomotic leakage rate in patients, who received mechanical bowel preparation and oral antibiotics before elective restorative resection for primary rectal cancer, were included. A meta-analysis was conducted based on the risk ratios of anastomotic leakage.

RESULTS

Among 839 studies, 5 studies met the eligibility criteria. The median number of patients were 6111 (80-29,739). The combination of preoperative mechanical bowel preparation and oral antibiotics was associated with a decreased risk of anastomotic leakage (risk ratio = 0.52 (95% confidence interval 0.39-0.69), p-value < 0.001). Limitations included a low number of studies, small sample sizes and the studies being rather heterogenous.

CONCLUSION

This systematic review and meta-analysis found that the use of mechanical bowel preparation and oral antibiotics is associated with a decreased risk of anastomotic leakage among patients undergoing restorative resection for primary rectal cancer. The limitations of the review should be taken into consideration when interpreting the results.

Has network meta-analysis resolved the controversies related to bowel preparation in elective colorectal surgery?

AIM

There are discrepancies in the guidelines on preparation for colorectal surgery. While intravenous antibiotics (IV) are usually administered, the use of mechanical bowel preparation (MBP) and/or oral antibiotics (OA) is controversial. A recent network meta-analysis (NMA) demonstrated that the addition of OA reduced incisional surgical site infections (iSSIs) by more than 50%. We aimed to perform a NMA including only the highest quality randomized clinical trials (RCTs) in order to determine the ranking of different treatment strategies and assess these RCTs for methodological problems that may affect the conclusions of the NMAs.

METHOD

A NMA was performed according to PRISMA guidelines. RCTs of adult patients undergoing elective colorectal surgery with appropriate antibiotic cover and with at least 250 participants recruited, clear definition of endpoints and duration of follow-up extending beyond discharge from hospital were included. The search included Medline, Embase, Cochrane and SCOPUS databases. Primary outcomes were iSSI and anastomotic leak (AL). Statistical analysis was performed in Stata v.15.1 using frequentist routines.

RESULTS

Ten RCTs including 5107 patients were identified. Treatments compared IV (2218 patients), IV + OA (460 patients), MBP + IV (1405 patients), MBP + IV + OA (538 patients) and OA (486 patients). The likelihood of iSSI was significantly lower for IV + OA (rank 1) and MBP + IVA + OA (rank 2), reducing iSSIs by more than 50%. There were no differences between treatments for AL. Methodological issues included differences in definition, assessment and frequency of primary endpoint infections and the limited number of participants included in some treatment options.

CONCLUSION

While this NMA supports the addition of OA to IV to reduce iSSI it also highlights unanswered questions and the need for well-designed pragmatic RCTs.

A Review of Bowel Preparation Before Colorectal Surgery

Infectious complications are the biggest problem during bowel surgery, and one of the approaches to minimize them is the bowel cleaning method. It was expected that bowel cleaning could facilitate bowel manipulation as well as prevent infectious complications and further reduce anastomotic leakage. In the past, with the development of antibiotics, bowel cleaning and oral antibiotics (OA) were used together. However, with the success of emergency surgery and Enhanced Recovery After Surgery, bowel cleaning was not routinely performed. Consequently, bowel cleaning using OA was gradually no longer used. Recently, there have been reports that only bowel cleaning is not helpful in reducing infectious complications such as surgical site infection (SSI) compared to OA and bowel cleaning. Accordingly, in order to reduce SSI, guidelines are changing the trend of only intestinal cleaning. However, a consistent regimen has not yet been established, and there is still controversy depending on the location of the lesion and the surgical method. Moreover, complications such as Clostridium difficile infection have not been clearly analyzed. In the present review, we considered the overall bowel preparation trends and identified the areas that require further research.

Intestinal motility distal of a deviating ileostomy after rectal resection with the construction of a primary anastomosis: results of the prospective COLO-MOVE study

PURPOSE

No consensus exists regarding the use of preoperative bowel preparation for patients undergoing a low anterior resection (LAR). Several comparative studies show similar outcomes when a single time enema (STE) is compared with mechanical bowel preparation (MBP). It is hypothesized that STE is comparable with MBP due to a decrease in intestinal motility distal of a newly constructed diverting ileostomy (DI).

METHODS

In this prospective single-centre cohort study, patients undergoing a LAR with primary anastomosis and DI construction were given a STE 2 h pre-operatively. Radio-opaque markers were inserted in the efferent loop of the DI during surgery, and plain abdominal X-rays were made during the first, third, fifth and seventh postoperative day to visualize intestinal motility.

RESULTS

Thirty-nine patients were included. Radio-opaque markers were situated in the ileum or right colon in 100%, 100% and 97.1% of the patients during respectively the first, third and fifth postoperative day. One patient had its most distal marker situated in the left colon during day five. In none of the patients, the markers were seen distal of the anastomosis.

CONCLUSION

Intestinal motility distally of the DI is decreased in patients who undergo a LAR resection with the construction of an anastomosis and DI, while preoperatively receiving a STE.