Right hemicolectomy anastomotic leak study: a review of right hemicolectomy in the binational clinical outcomes registry (BCOR)

What Is the Role of the Gut Microbiota in Anastomotic Leakage After Colorectal Resection? A Scoping Review of Clinical and Experimental Studies

Background: Anastomotic leakage (AL) still remains a common complication after colorectal anastomosis that leads to increased morbidity and mortality. The gut microbiota has been hypothesized as one of the risk factors associated with anastomotic leakage. The aim of the present study was to summarize all existing clinical and experimental studies that evaluate the impact of intestinal microbiota on anastomotic leakage after colorectal resection. Methods: The present scoping review was designed according to PRISMA recommendations and a systematic search in Medline, Scopus, EMBASE, Clinicaltrials.gov, Google Scholar, and CENTRAL was conducted until September 2024. Results: Overall, 7 clinical and 5 experimental studies were included. A diminished α-diversity of the gut microbiota in patients suffering from AL was demonstrated. Specific microbe genera, such as Lachnospiraceae, Bacteroidaceae, Bifidobacterium, Acinetobacter, Fusobacterium, Dielma, Elusimicronium, Prevotella, and Faecalibacterium, seem to be associated with AL. However, specific genera, like Prevotella, Streptococcus, Eubacterium, Enterobacteriaceae, Klebsiella, Actinobacteria, Gordonibacter, Phocaeicola, and Ruminococcus2, seem to be protective against AL. Experimental studies highlighted that the Western diet seems to affect microbiota diversity and increases the AL rate, whereas anastomotic healing seems to be impaired by high metalloproteinase production and increased collagenase activity. Conclusions: The intestinal microbiota seems to play an important role in anastomotic leakage after colorectal resection. Specific interventions targeting the microbiota's composition and the pathophysiological mechanisms by which it impairs anastomotic healing could diminish the risk for anastomotic leakage and improve clinical outcomes. However, future studies should be based on prospective design and eliminate heterogeneity.

Is mechanical bowel preparation mandatory for elective colon surgery? A systematic review and meta-analysis

BACKGROUND

Growing evidence demonstrates minimal impact of mechanical bowel preparation (MBP) on reducing postoperative complications following elective colectomy. This study investigated the necessity of MBP prior to elective colonic resection.

METHOD

A systematic literature review was conducted across PubMed, Ovid, and the Cochrane Library to identify studies comparing the effects of MBP with no preparation before elective colectomy, up until May 26, 2023. Surgical-related outcomes were compiled and subsequently analyzed. The primary outcomes included the incidence of anastomosis leakage (AL) and surgical site infection (SSI), analyzed using Review Manager Software (v 5.3).

RESULTS

The analysis included 14 studies, comprising seven RCTs with 5146 participants. Demographic information was consistent across groups. No significant differences were found between the groups in terms of AL ((P = 0.43, OR = 1.16, 95% CI (0.80, 1.68), I2 = 0%) or SSI (P = 0.47, OR = 1.20, 95% CI (0.73, 1.96), I2 = 0%), nor were there significant differences in other outcomes. Subgroup analysis on oral antibiotic use showed no significant changes in results. However, in cases of right colectomy, the group without preparation showed a significantly lower incidence of SSI (P = 0.01, OR = 0.52, 95% CI (0.31, 0.86), I2 = 1%). No significant differences were found in other subgroup analyses.

CONCLUSION

The current evidence robustly indicates that MBP before elective colectomy does not confer significant benefits in reducing postoperative complications. Therefore, it is justified to forego MBP prior to elective colectomy, irrespective of tumor location.

Collagenase-producing bacteria are common in anastomotic leakage after colorectal surgery: a systematic review

PURPOSE

Some gut bacteria can produce enzymes (collagenases) that can break down collagen in the intestinal wall. This could be a part of the pathophysiology of anastomotic leakage (AL). This systematic review aimed to investigate if such bacteria were present more frequently in AL patients versus non-AL patients following colorectal surgery.

METHODS

This systematic review was reported according to the PRISMA and AMSTAR guidelines. Before the literature search, a study protocol was registered at PROSPERO (CRD42022363454). We searched PubMed, EMBASE, Google Scholar, and Cochrane CENTRAL on April 9th, 2023, for randomized and observational human studies of AL following colorectal surgery with information on gastrointestinal bacteria. The primary outcome was bacteria with the potential to produce collagenase. The risk of bias was assessed with the Newcastle-Ottawa Scale, as all studies were observational.

RESULTS

We included 15 studies, with a total of 52,945 patients, of which 1,747 had AL, and bacteriological information from feces, mucosa, the resected specimen, or drain fluid was presented. In 10 of the 15 studies, one or more collagenase-producing bacteria were identified in the patients with AL. Neither the bacteria nor the collagenase production were quantified in any of the studies. The studies varied greatly in terms of sample material, analytical method, and time of collection. Studies using DNA sequencing methods did not report findings of collagenase-producing bacteria.

CONCLUSION

Collagenase-producing bacteria are more common in patients with AL following colorectal surgery than in patients without AL, but the significance is unclear. From the current studies, it is not possible to determine the pathogenicity of the individual gut bacteria.

Right hemicolectomy for colon cancer: does the anastomotic configuration affect short-term outcomes?

OBJECTIVES

Right hemicolectomy is a common colorectal operation for resection of cancers of the right colon. The ileocolic anastomosis may be created using a stapled end-to-side, stapled side-to-side or handsewn technique. Anastomotic leak and post-operative bleeding are uncommon but serious causes of morbidity and mortality, while post-operative ileus contributes to prolonged length of stay. The aim of this study was to evaluate differences in short-term outcomes between different anastomotic configurations following right hemicolectomy for colon cancer.

METHODS

We conducted a retrospective study using data from the Bowel Cancer Outcomes Registry (BCOR), including 94 hospitals across Australia and New Zealand, of all patients who underwent right hemicolectomy or extended right hemicolectomy for colon cancer with formation of a primary anastomosis between 2007 and 2021.

RESULTS

We included 8164 patients in the analysis. There was no significant difference in rates of anastomotic leak and anastomotic bleeding based on anastomotic technique. A stapled end-to-side anastomosis was associated with a lower rate of post-operative ileus than stapled side-to-side anastomosis (6.5% vs. 7.2%; P = 0.03).

CONCLUSION

Both handsewn and stapled anastomosis techniques may be utilized for oncologic right hemicolectomy, with comparable rates of anastomotic leak and post-operative bleeding. Stapled end-to-side anastomosis resulted in lower rates of prolonged ileus compared to stapled side-to-side anastomoses.