Randomized clinical trial of the influence of mechanical bowel preparation on faecal microflora in patients undergoing colonic cancer resection

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.

Mechanical bowel preparation in elective colorectal surgery: a propensity score-matched analysis of the Italian colorectal anastomotic leakage (iCral) study group prospective cohorts

Retrospective evaluation of the effects of mechanical bowel preparation (MBP) on data derived from two prospective open-label observational multicenter studies in Italy regarding elective colorectal surgery. MBP for elective colorectal surgery remains a controversial issue with contrasting recommendations in current guidelines. The Italian ColoRectal Anastomotic Leakage (iCral) study group, therefore, decided to estimate the effects of no MBP (treatment variable) versus MBP for elective colorectal surgery. A total of 8359 patients who underwent colorectal resection with anastomosis were enrolled in two consecutive prospective studies in 78 surgical centers in Italy from January 2019 to September 2021. A retrospective PSMA was performed on 5455 (65.3%) cases after the application of explicit exclusion criteria to eliminate confounders. The primary endpoints were anastomotic leakage (AL) and surgical site infections (SSI) rates; the secondary endpoints included SSI subgroups, overall and major morbidity, reoperation, and mortality rates. Overall length of postoperative hospital stay (LOS) was also considered. Two well-balanced groups of 1125 patients each were generated: group A (No MBP, true population of interest), and group B (MBP, control population), performing a PSMA considering 21 covariates. Group A vs. group B resulted significantly associated with a lower risk of AL [42 (3.5%) vs. 73 (6.0%) events; OR 0.57; 95% CI 0.38-0.84; p = 0.005]. No difference was recorded between the two groups for SSI [73 (6.0%) vs. 85 (7.0%) events; OR 0.88; 95% CI 0.63-1.22; p = 0.441]. Regarding the secondary endpoints, no MBP resulted significantly associated with a lower risk of reoperation and LOS > 6 days. This study confirms that no MBP before elective colorectal surgery is significantly associated with a lower risk of AL, reoperation rate, and LOS < 6 days when compared with MBP.

Probiotics in Postoperative Pain Management

Postoperative pain is the unpleasant sensory and emotional experience after surgery, its origin being both the inflammatory reaction induced by the surgical trauma on the abdominal wall and the splanchnic pain induced by the activation of nociceptors of the viscera, which are highly sensitive to distension, ischemia, and inflammation. Nowadays, it is well recognized that there is a close relationship between the gut microbiome and pain perception, and that microbiome is highly affected by both anesthesia and surgical manipulation. Thus, efforts to restore the disturbed microbiome via supplementation with beneficial bacteria, namely probiotics, seem to be effective. In this article, the knowledge gained mainly from experimental research on this topic is analyzed, the concluding message being that each probiotic strain works in its own way towards pain relief.

Benefits of Probiotic Pretreatment on the Gut Microbiota and Minor Complications after Bowel Preparation for Colonoscopy: A Randomized Double-Blind, Placebo-Controlled Pilot Trial

The aim of this study was to evaluate the effects of probiotic pretreatment on the alteration and recovery of gut microbiota after bowel preparation and its correlation with minor complications. This was a randomized, double-blind, placebo-controlled pilot trial that included participants 40-65 years of age. Participants were randomly provided probiotics (active group) or placebo (placebo group) for 1 month before the colonoscopy and their feces collected. A total of 51 participants were included in the present study (26 in the active group and 25 in the placebo group). In the active group, the microbial diversity, evenness, and distribution were not significantly changed between before and after bowel preparation, but did change in the placebo group. The number of gut microbiota that decreased after bowel preparation in the active group was lower than in the placebo group. On the seventh day after colonoscopy, the gut microbiota in the active group was restored to almost the same level as before bowel preparation. In addition, we identified that several strains were assumed as key microbiota in early colonization and some taxa were increased only in the active group after bowel preparation. In multivariate analysis, taking probiotics before bowel preparation was identified as a significant factor for decreasing the duration of minor complications (odds ratio 0.13, 95% confidence interval 0.02-0.60, p = 0.027). Probiotic pretreatment had benefits on the alteration and recovery of gut microbiota and possible complications after bowel preparation. Probiotics may also aid in the early colonization of key microbiota.

High-intensity mechanical bowel preparation before curative colorectal surgery is associated with poor long-term prognosis

PURPOSE

Mechanical bowel preparation (MBP) has been widely used to reduce intestinal feces and bacteria and is considered necessary to prevent surgical infections. However, it is still controversial which intensity level of MBP is the most beneficial for patients before colorectal surgery. Our study aimed to determine the impact of different intensity levels of MBP on the progression-free survival (PFS) and overall survival (OS) for colorectal cancer (CRC) patients.

METHODS

We evaluated 694 patients pathologically diagnosed with CRC and underwent MBP before surgery at 4 general hospitals from January 2011 to December 2015. The survival status of patients, the disease progression, and the time of death or progression were obtained through telephone follow-up at the deadline October 10, 2018. Hazard ratios were estimated by Cox proportional hazard models. Survival was assessed using the Kaplan-Meier method followed by the log-rank test.

RESULTS

Of 694 patients included, 462 received low-intensity MBP and 232 received high-intensity MBP. A significantly higher PFS in low-intensity MBP was observed (p = 0.009). PFS at 2000 days was 69.331% in the low-intensity arm and 58.717% in the high-intensity arm. Patients who underwent low-intensity MBP also showed higher OS (p = 0.009). Nine patients in the low-intensity MBP group received secondary surgery, and two patients in the high-intensity MBP group received secondary surgery.

CONCLUSIONS

In this retrospective cohort, low-intensity MBP was associated with better PFS and OS, which could provide a reference for doctors when choosing the intensity of MBP.

Dysbiosis and Gastrointestinal Surgery: Current Insights and Future Research

Surgery of the gastrointestinal tract can result in deep changes among the gut commensals in terms of abundance, function and health consequences. Elective colorectal surgery can occur for neoplastic or inflammatory bowel disease; in these settings, microbiota imbalance is described as a preoperative condition, and it is linked to post-operative complications, as well. The study of bariatric patients led to several insights into the role of gut microbiota in obesity and after major surgical injuries. Preoperative dysbiosis and post-surgical microbiota reassessment are still poorly understood, and they could become a key part of preventing post-surgical complications. In the current review, we outline the most recent literature regarding agents and molecular pathways involved in pre- and post-operative dysbiosis in patients undergoing gastrointestinal surgery. Defining the standard method for microbiota assessment in these patients could set up the future approach and clinical practice.

A Network Meta-Analysis and GRADE Assessment of the Effect of Preoperative Oral Antibiotics with and Without Mechanical Bowel Preparation on Surgical Site Infection Rate in Colorectal Surgery

Objective

To compare the effect of different methods of bowel preparation on the incidence of surgical site infections (SSI), anastomotic leakage (AL), and mortality in patients undergoing elective colorectal surgery.

Background

Recent guidelines advise mechanical bowel preparation with oral antibiotics (MBP-OA) for the prevention of SSI in colorectal surgery. Recent trials suggest oral antibiotics (OA) alone may be sufficient.

Methods

PubMed, MEDLINE, and Embase were searched from inception until 10-08-2021. We included randomized controlled trials (RCTs) comparing multiple methods of bowel preparation (mechanical bowel preparation [MBP], OA, MBP-OA, or no preparation) with regards to clinical outcomes such as incidence of SSI, AL, and mortality rates. A frequentist random-effects network meta-analysis was conducted to estimate the network effects of the different treatment options.

Results

We included 48 studies with 13,611 patients. Compared to no preparation, combined direct and indirect network estimates showed a relative risk (RR) for SSI of 0.57 (95% confidence interval [CI], 0.45-0.72) for MBP-OA, 0.68 (95% CI, 0.49-0.95) for OA, and 1.05 (95% CI, 0.87-1.26) for MBP. The RR for MBP-OA compared to OA was 0.84 (95% CI, 0.60-1.19); in sensitivity analysis of mainly laparoscopic procedures this effect of MBP-OA was more profound (RR, 0.56; 95% CI, 0.31-0.99).

Conclusions

This network meta-analysis of RCTs finds that both mechanical bowel preparation with oral antibiotics and oral antibiotics alone are comparably effective in the prevention of SSI. The evidence is uncertain about the relative benefit of MBP-OA compared to OA alone. Therefore, it seems justified to use either of the 2 for the prevention of SSI in colorectal surgery.

Alterations in co-abundant bacteriome in colorectal cancer and its persistence after surgery: a pilot study

There is growing interest in the role of gut microbiome in colorectal cancer (CRC), ranging from screening to disease recurrence. Our study aims to identify microbial markers characteristic of CRC and to examine if changes in bacteriome persist after surgery. Forty-nine fecal samples from 25 non-cancer (NC) individuals and 12 CRC patients, before and 6-months after surgery, were collected for analysis by bacterial 16S rRNA gene sequencing. Bacterial richness and diversity were reduced, while pro-carcinogenic bacteria such as Bacteroides fragilis and Odoribacter splanchnicus were increased in CRC patients compared to NC group. These differences were no longer observed after surgery. Comparison between pre-op and post-op CRC showed increased abundance of probiotic bacteria after surgery. Concomitantly, bacteria associated with CRC progression were observed to have increased after surgery, implying persistent dysbiosis. In addition, functional pathway predictions based on the bacterial 16S rRNA gene data showed that various pathways were differentially enriched in CRC compared to NC. Microbiome signatures characteristic of CRC comprise altered bacterial composition. Elements of these dysbiotic signatures persists even after surgery, suggesting possible field-change in remnant non-diseased colon. Future studies should involve a larger sample size with microbiome data collected at multiple time points after surgery to examine if these dysbiotic patterns truly persist and also correlate with disease outcomes.

Evaluating the Role of Probiotics in the Prevention and Management of Age-Related Diseases

The human lifespan has been significantly increased due to scientific advancements in the management of disease; however, the health span of the aging population does not follow the same trend. Aging is the major risk factor for multimorbidity that is derived from the progressive loss of homeostasis, immunological and stem cell exhaustion, as well as exacerbated inflammation responses. Age-related diseases presenting with high frequencies include neurodegenerative, musculoskeletal, cardiovascular, metabolic diseases and cancer. These diseases can be co-morbid and are usually managed using a disease-specific approach that can eventually lead to polypharmacy, low medication adherence rates and undesired drug-drug interactions. Novel studies suggest targeting the shared biological basis of age-related diseases to retard the onset and manage their manifestations. Harvesting the anti-inflammatory and immunomodulatory capacity of probiotics to tackle the root cause of these diseases, could pose a viable alternative. In this article, a comprehensive review of the effects of probiotic supplementation on the molecular pathogenesis of age-related diseases, and the potential of probiotic treatments as preventative or alleviatory means is attempted. Furthermore, issues on the safety and efficiency of probiotic supplementation, as well as the pitfalls of current clinical studies are discussed, while new perspectives for systematic characterization of probiotic benefits on aged hosts are outlined.

Combined mechanical and oral antibiotic bowel preparation is associated with prolonged recurrence-free survival following surgery for colorectal cancer

BACKGROUND AND OBJECTIVES

Recent studies suggest that bacteria influence the pathogenesis of primary colorectal cancer (CRC), yet their role in recurrence after resection is largely unknown. We have discovered that collagenase-producing bacteria promote cancer recurrence in mice, and that antibiotic bowel decontamination decreases colonization of these same organisms in humans. We hypothesized that preoperative combined mechanical and oral antibiotic bowel preparation would improve disease-free survival (DFS) in patients undergoing surgery for CRC.

METHODS

We reviewed a cancer registry of patients treated for CRC at a tertiary center. Patients who received bowel preparation were compared to those that did not via a 1:1-propensity score matched for follow-up, age, sex, BMI, stage, location, chemoradiation, infection, anastomotic leak, and blood transfusion.

RESULTS

One thousand two hundred and seventy-nine patients met inclusion criteria. Following propensity score matching, 264 patients receiving bowel prep were matched to 264 patients who did not. Kaplan-Meier estimates showed that patients who received bowel prep had a significantly improved 5-year DFS compared to those that did not (76.3% vs. 64.2%; p < .01). Cox regression demonstrated that bowel prep was associated with improved DFS (HR, 0.57; 95% CI, 0.37-0.89; p < .01).

CONCLUSION

Combined mechanical and oral antibiotic bowel preparation is independently associated with improved recurrence-free survival in patients undergoing surgery for CRC.

Intestinal Microbiota in Colorectal Cancer Surgery

Simple Summary

The microbial communities of the intestine exist in a delicate balance with the human. Colorectal cancer is one of the most common gastrointestinal malignancies, and the microbiota seems to be related to it. The intestinal microbiota of patients after colorectal surgery is changed due to surgical stress and other perioperative factors. The occurrence of complications after colorectal cancer (CRC) surgery may depend on these bacterial shifts, which could also be associated with prognosis and survival in postoperative CRC patients.

Abstract

The intestinal microbiota consists of numerous microbial species that collectively interact with the host, playing a crucial role in health and disease. Colorectal cancer is well-known to be related to dysbiotic alterations in intestinal microbiota. It is evident that the microbiota is significantly affected by colorectal surgery in combination with the various perioperative interventions, mainly mechanical bowel preparation and antibiotic prophylaxis. The altered postoperative composition of intestinal microbiota could lead to an enhanced virulence, proliferation of pathogens, and diminishment of beneficial microorganisms resulting in severe complications including anastomotic leakage and surgical site infections. Moreover, the intestinal microbiota could be utilized as a possible biomarker in predicting long-term outcomes after surgical CRC treatment. Understanding the underlying mechanisms of these interactions will further support the establishment of genomic mapping of intestinal microbiota in the management of patients undergoing CRC surgery.

Mucosal cancer-associated microbes and anastomotic leakage after resection of colorectal carcinoma

BACKGROUND

Clinical and experimental evidence suggests that colorectal mucosal microbiota changes during colorectal carcinogenesis and may impair colorectal anastomotic wound healing. Thus, we hypothesized that amounts of colorectal cancer-associated microbes in colorectal tissue might be associated with anastomotic leakage after resection for colorectal carcinoma.

METHODS

We analyzed 256 fresh frozen tissues of colorectal cancer from patients who underwent elective colorectal resection and anastomosis. Amounts of colorectal cancer-associated microbes, including Fusobacterium nucleatum, Escherichia coli possessing the polyketide synthase (pks) gene cluster, Enterococcus faecalis, and Bifidobacterium genus, in colorectal cancer tissues were measured by quantitative polymerase chain reaction assay; we equally dichotomized positive cases (high versus low). Multivariable logistic regression analysis was conducted to assess associations of these microbes with anastomotic leakage, adjusting for patient and tumor characteristics, and surgery-related factors.

RESULTS

Fusobacterium nucleatum, pks-positive Escherichia coli, Enterococcus faecalis, and Bifidobacterium genus were detected in colorectal carcinoma tissue in 140 (54%), 94 (36%), 193 (75%), and 89 (35%) of 256 cases, respectively. Compared with Bifidobacterium genus-negative cases, Bifidobacterium genus-high cases were associated with an increased risk of anastomotic leakage (multivariable odds ratio, 3.96; 95% confidence interval, 1.50 to 10.51; P_trend = 0.004). The association of Fusobacterium nucleatum, pks-positive Escherichia coli, or Enterococcus faecalis with anastomotic leakage was not statistically significant.

CONCLUSIONS

The amount of Bifidobacterium genus in colorectal tissue is associated with an increased risk of anastomotic leakage after resection for colorectal cancer. These findings need to be validated to target gastrointestinal microflora for the prevention of anastomotic leakage after colorectal resection.

Current evidence on the relation between gut microbiota and intestinal anastomotic leak in colorectal surgery

BACKGROUND

Anastomotic leak (AL) is a major complication in colorectal surgery. It worsens morbidity, mortality and oncological outcomes in colorectal cancer. Some evidence suggests a potential effect of the intestinal microbiome on wound healing. This review aims to provide a comprehensive review on historical and current evidence regarding the relation between the gastrointestinal microbiota and AL in colorectal surgery, and the potential microbiota-modifying effect of some perioperative commonly used measures.

DATA SOURCES

A comprehensive search was conducted in Pubmed, Medline and Embase for historical and current clinical and animal studies addressing perioperative intestinal microbiota evaluation, intestinal healing and AL.

CONCLUSIONS

Evidence on microbes' role in AL is mainly derived from animal experiments. The microbiota's composition and implications are poorly understood in surgical patients. Elaborate microbiota sequencing is required in colorectal surgery to identify potentially beneficial microbial profiles that could lead to specific perioperative microbiome-altering measures and improve surgical and oncological outcomes.

Randomized controlled trial of probiotic use for post-colonoscopy symptoms

BACKGROUND

Symptoms of bloating, discomfort and altered bowel function persist post-colonoscopy in up to 20% of patients. A previous randomized controlled trial of probiotics for post-colonoscopy symptoms has demonstrated a reduction in duration of pain with the use of probiotics. This was performed with air insufflation and the question was asked whether the effect would persist with the use of carbon dioxide to insufflate the colon.

METHODS

Eligible patients were recruited and randomized to receive either probiotic or placebo capsules post colonoscopy. A questionnaire was completed documenting the presence of pre-procedural and post-procedural symptoms for the following 2 weeks. The results were entered into a database and processed by an independent statistician. The primary outcome was mean pain score and incidence of bloating over the first 7 days and at 14 days post procedure. The secondary outcome was the time to return of normal bowel function.

RESULTS

Two hundred and forty participants were recruited and randomized (120 probiotic and 120 placebo). Data were available for 75 patients in the probiotic and 75 in the placebo group. There was no significant difference between groups in post-procedural discomfort, bloating nor time to return of normal bowel function. Subgroup analysis of the patients with preexisting symptoms showed a reduction in incidence of bloating with the use of probiotics.

CONCLUSION

There may be a role for the use of probiotics in the subgroup of patients with preexisting symptoms; however, routine use of probiotics to ameliorate post-procedural symptoms of carbon dioxide insufflation colonoscopy cannot be advocated.

Gut microbiome, surgical complications and probiotics

The trigger for infectious complications in patients following major abdominal operations is classically attributed to endogenous enteral bacterial translocation, due to the critical condition of the gut. Today, extensive gut microbiome analysis has enabled us to understand that almost all "evidence-based" surgical or medical intervention (antibiotics, bowel preparation, opioids, deprivation of nutrition), in addition to stress-released hormones, could affect the relative abundance and diversity of the enteral microbiome, allowing harmful bacteria to proliferate in the place of depressed beneficial species. Furthermore, these bacteria, after tight sensing of host stress and its consequent humoral alterations, can and do switch their virulence accordingly, towards invasion of the host. Probiotics are the exogenously given, beneficial clusters of live bacteria that, upon digestion, seem to succeed in partially restoring the distorted microbial diversity, thus reducing the infectious complications occurring in surgical and critically ill patients. This review presents the latest data on the interrelationship between the gut microbiome and the occurrence of complications after colon surgery, and the efficacy of probiotics as therapeutic instruments for changing the bacterial imbalance.

Laparoscopic colon resection: To prep or not to prep? Analysis of 1535 patients

BACKGROUND

Mechanical bowel preparation (MBP) before elective open colon resection does not reduce the rate of postoperative anastomotic leakage. However, MBP is still routinely used in many countries, and there are very limited data regarding the utility of preoperative MBP in patients undergoing laparoscopic colon resection (LCR). The aim of this study was to challenge the use of MBP before elective LCR.

METHODS

It is a retrospective analysis of a prospectively collected database. All patients undergoing elective LCR with primary anastomosis and no stoma were included. Preoperative MBP with polyethylene glycol solution was used routinely between April 1992 and December 2004, and then it was abandoned. The early postoperative outcomes in patients who had preoperative MBP (MBP group) and in patients who underwent LCR without preoperative MBP (No-MBP group) were compared.

RESULTS

From April 1992 to December 2014, 1535 patients underwent LCR: 706 MBP patients and 829 No-MBP patients. There were no differences in demographic data, indication for surgery and type of procedure performed between MBP and No-MBP group patients. The incidence of anastomotic leakage was similar between the two groups (3.4 vs. 3.6 %, p = 0.925). No differences were observed in intra-abdominal abscesses (0.6 vs. 0.8 %, p = 0.734), wound infections (0.6 vs. 1.4 %, p = 0.149), infectious extra-abdominal complications (1.8 vs. 3 %, p = 0.190), and non-infectious complications (6.1 vs. 6.8 %, p = 0.672). The overall reoperation rate was 4.6 % for MBP patients and 5 % for No-MBP patients (p = 0.813).

CONCLUSION

The use of preoperative MBP does not seem to be associated with lower incidence of intra-abdominal septic complications after LCR.

Randomized controlled trial of probiotics after colonoscopy

BACKGROUND

Up to 20% of patients have ongoing abdominal symptoms at day 2 and beyond following colonoscopy. It was hypothesized that some of these symptoms are related to alterations in gut microbiota secondary to bowel preparation and would improve with probiotics compared with placebo.

METHODS

Patients were given either a probiotic or placebo capsule in the days following colonoscopy. Colonoscopy was performed with air insufflation. The probiotic capsule contained the strains Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07. Patients recorded their symptoms at 1 h, 1, 2, 4, 7 and 14 days post colonoscopy and returned results once their symptoms had resolved. The primary outcomes used were the length of days to resolution of bloating, abdominal pain and altered bowel function post colonoscopy.

RESULTS

A total of 320 patients were randomized. After loss to follow-up and withdrawal, 133 patients were analysed in the probiotic group and 126 in the placebo group. Patients having probiotic had a lower number of pain days following colonoscopy, 1.99 versus 2.78 days (P < 0.033). There was no significant difference in bloating or return to normal bowel habit days (P = 0.139 and 0.265 respectively). Subgroup analysis revealed that patients with pre-existing abdominal pain benefited from probiotics in number of pain days, 2.16 versus 4.08 (P = 0.0498).

CONCLUSION

Our study has shown a significant reduction in the duration of pain days post colonoscopy in patients taking probiotic compared with placebo. No significant effect was seen in terms of return to normal bowel function or bloating post colonoscopy.

Efficacy of perioperative synbiotics treatment for the prevention of surgical site infection after laparoscopic colorectal surgery: a randomized controlled trial

PURPOSE

The aim of this study was to assess the effect of perioperative oral administration of synbiotics on the surgical outcome in patients undergoing laparoscopic colorectal resection.

METHODS

In this single-center randomized, controlled trial, patients scheduled to undergo elective laparoscopic colorectal surgery were eligible to participate and randomly assigned to a synbiotics group or a control group. The primary study outcome was the development of infectious complications, particularly surgical site infection (SSI), within 30 days of surgery.

RESULTS

In this study, 379 patients were enrolled and randomly assigned (173 to the synbiotics group and 206 to the control group), of whom 362 patients (168 to the synbiotics group and 194 to the control group) were eligible for this study. SSI occurred in 29 (17.3%) patients in the synbiotics group and 44 (22.7%) patients in the control group (OR: 0.761, 95% CI 0.50-1.16; p = 0.20). Overall, the rate of postoperative complications, including anastomotic leakage, did not differ significantly between the two groups. Synbiotics treatment reversed the changes in fecal bacteria and organic acids after surgery and suppressed the increases in potentially pathogenic species, such as Clostridium difficile.

CONCLUSION

The efficacy of perioperative administration of synbiotics was not validated as a treatment for reducing the incidence of infectious complications after laparoscopic colorectal resection. However, the microbial imbalance, in addition to the reduction in organic acids, could be improved by perioperative synbiotics treatment.

Relationship between the pH of enema solutions and intestinal damage in rabbits

Mechanical enemas can lead to intestinal mucosal injuries and bowel barrier damage, presenting as electrolyte disturbances and functional intestinal disorders. Most researchers believe that the mechanism of injury is related to osmolality, volume and temperature of the solution, infusion pressure, and the composition of the enema tube. We hypothesized that the pH of the enema solution may also contribute to intestinal damage. We administered enema solutions--normal saline, soapsuds, or vinegar (neutral, alkaline, or acidic solutions, respectively)--to three groups of rabbits (n = 20 per group). The solutions were standardized for volume and temperature and the soapsuds and vinegar solutions were adjusted to be isotonic with normal saline or deionized water. We also included a control group (n = 20) in which the enema tubes were inserted but no solution was administered. We biopsied 3 sites (rectum and distal and proximal colon). Damage to intestinal mucosa was observed by light microscopy and transmission electron microscopy. In order to explore the detection of damage using noninvasive methods, cyclooxygenase (COX)-2 gene expression was measured in the exfoliated cells gathered from postenema defecation. Epithelial loss, inflammatory reaction, and cellular microstructure damage was increased in the vinegar and soapsuds groups. Also, exfoliated cells in these groups had higher COX-2 expression than the normal saline group. The acidic and alkaline enema solutions thus caused more severe damage to the intestinal mucosa compared to the neutral liquid, supporting our hypothesis. Further, the detection of COX-2 expression shows promise as a noninvasive method for estimating enema-induced damage.

Relationship between the severity of diversion colitis and the composition of colonic bacteria: a prospective study

Background/Aims

Diversion colitis is the inflammation of the excluded segment of the colon in patients undergoing ostomy. It has been suggested that a change in colonic flora may lead to colitis; however, direct evidence for this disease progression is lacking. The aim of this study was to evaluate the relationship between the severity of diversion colitis and the composition of colonic bacteria.

Methods

We used culture methods and polymerase chain reaction to analyze the colonic microflora of patients who underwent rectal cancer resection with or without diversion ileostomy. In the diversion group, we also evaluated the severity of colonoscopic and pathologic colitis before reversal.

Results

This study enrolled 48 patients: 26 in the diversion group and 22 in the control group. Significant differences were observed between the two groups in the levels of Staphylococcus (p=0.038), Enterococcus (p<0.001), Klebsiella (p<0.001), Pseudomonas (p=0.015), Lactobacillus (p=0.038), presence of anaerobes (p=0.019), and Bifidobacterium (p<0.001). A significant correlation between the severity of colitis and bacterial composition was only observed for Bifidobacterium (p=0.005, correlation coefficient=-0.531).

Conclusions

The colonic microflora differed significantly between the diversion and control groups. Bifidobacterium was negatively correlated with the severity of diversion colitis.

A prospective randomized multicenter study of Turkish Society of Urooncology comparing two different mechanical bowel preparation methods for radical cystectomy

OBJECTIVE

To investigate the outcomes and complication rates of urinary diversion using mechanical bowel preparation (BP) with 3 day conventional and limited BP method through a standard perioperative care plan.

MATERIALS AND METHODS

This study was designed as a prospective randomized multicenter trial. All patients were randomized to 2 groups. Patients in standard 3-day BP protocol received diet restriction, oral antibiotics to bowel flora, oral laxatives, and saline enemas over a 3-day period, whereas limited the BP arm received liberal use of liquid diet, sodium phosphate laxative, and self administered enema the day before surgery. All patients received same perioperative treatment protocol. The endpoints for the assessment of outcome were anastomotic leakage, wound infection, wound dehiscence, intraperitoneal abscess, peritonitis, sepsis, ileus, reoperation, and mortality. Bowel function recovery, including time to first bowel movement, time to first oral intake, time to regular oral intake, and length of hospital stay were also assessed.

RESULTS

Fifty-six patients in 3-day BP and 56 in limited BP arm were evaluable for the study end points. Postoperatively, 1 patient in limited BP and 2 patients in 3-day BP arm died. There was no statistical difference in any of the variables assessed throughout the study, however, a favorable return of bowel function and time to discharge as well as lower complication rate were observed in limited BP group.

CONCLUSIONS

Regarding all endpoints, including septic and nonseptic complications, current clinical research offers no evidence to show any advantage of 3-day BP over limited BP.

Mechanical bowel preparation does not influence outcomes following colonic cancer resection

Background

Meta-analyses have indicated that preoperative mechanical bowel preparation (MBP) confers no clear benefit and may indeed be harmful for patients with colorectal cancer. The effects of bowel preparation on longer-term outcomes have not been reported. The aim was to compare long-term survival and surgical complications in patients who did or did not receive MBP before surgery for colonic cancer.

Methods

This was a retrospective cohort study of all patients undergoing potentially curative surgery for colonic cancer after routine hospital admission in the West of Scotland between January 2000 and December 2005. Clinical audit data were linked to cancer registrations and death certificates. Kaplan–Meier and Cox proportional hazards models were used to explore determinants of survival.

Results

A total of 1730 patients underwent potentially curative surgery for colonic cancer, of whom 886 (51·2 per cent) were men. The mean(s.d.) age was 69·7(10·6) years. Some 1460 patients (84·4 per cent) received MBP. Median follow-up was 3·5 (range 0·1–6·7) years. There were no statistically significant differences in 30-day postoperative complication rates between groups. The unadjusted hazard ratio (HR) for death from all causes for patients treated with MBP (versus no MBP) was 0·72 (95 per cent confidence interval 0·57 to 0·91). Multivariable analysis with adjustment for age, sex, socioeconomic circumstances, disease stage and presentation for surgery showed that MBP had no independent effect on all-cause mortality (HR 0·85, 0·67 to 1·10).

Conclusion

Neither postoperative complications nor long-term survival are improved by MBP before colonic cancer surgery.