Impact of Laparoscopic Colorectal Resection on Surgical Site Infection

Surgical Site Infections in Colorectal Cancer Surgeries: A Systematic Review and Meta-Analysis of the Impact of Surgical Approach and Associated Risk Factors

BACKGROUND

Surgical site infections (SSIs) represent a noteworthy contributor to both morbidity and mortality in the context of patients who undergo colorectal surgery. Several risk factors have been identified; however, their relative significance remains uncertain.

METHODS

We conducted a meta-analysis of observational studies from their inception up until 2023 that investigated risk factors for SSIs in colorectal surgery. A random-effects model was used to pool the data and calculate the odds ratio (OR) and 95% confidence interval (CI) for each risk factor.

RESULTS

Our analysis included 26 studies with a total of 61,426 patients. The pooled results showed that male sex (OR = 1.45), body mass index (BMI) ≥ 25 kg/m2 (OR = 1.09), American Society of Anesthesiologists (ASA) score ≥ 3 (OR = 1.69), were all independent risk factors for SSIs in colorectal surgery. Conversely, laparoscopic surgery (OR = 0.70) was found to be a protective factor.

CONCLUSIONS

The meta-analysis conducted revealed various risk factors, both modifiable and non-modifiable, associated with surgical site infections (SSIs) in colorectal surgery. These findings emphasize the significance of targeted interventions, including optimizing glycemic control, minimizing blood loss, and using laparoscopic techniques whenever feasible in order to decrease the occurrence of surgical site infections in this particular group of patients.

A meta-analysis of the risk factors for surgical site infection in patients with colorectal cancer

The purpose of the meta-analysis was to evaluate and compare the surgical site infection (SSI) risk factors in patients with colorectal cancer (CC). The results of this meta-analysis were analysed, and the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) were calculated using dichotomous or contentious random or fixed-effect models. For the current meta-analysis, 23 examinations spanning from 2001 to 2023 were included, encompassing 89 859 cases of CC. Clean-contaminated surgical site wounds had significantly lower infections (OR, 0.36; 95% CI, 0.20-0.64, p < 0.001) compared to contaminated surgical site wounds in patients with CCs. Males had significantly higher SSIs (OR, 1.18; 95% CI, 1.12-1.24, p < 0.001) compared to females in patients with CC. American Society of Anesthesiology score ≥3 h had a significantly higher SSI (OR, 1.42; 95% CI, 1.18-1.71, p < 0.001) compared to <3 score in patients with CCs. Body mass index ≥25 had significantly higher SSIs (OR, 1.54; 95% CI, 1.11-2.14, p = 0.01) compared to <25 in patients with CCs. The presence of stoma creation had a significantly higher SSI rate (OR, 2.28; 95% CI, 1.37-3.79, p = 0.001) compared to its absence in patients with CC. Laparoscopic surgery had significantly lower SSIs (OR, 0.68; 95% CI, 0.59-0.78, p < 0.001) compared to open surgery in patients with CC. The presence of diabetes mellitus had a significantly higher SSI rate (OR, 1.24; 95% CI, 1.15-1.33, p < 0.001) compared to its absence in patients with CCs. No significant difference was found in SSI rate in patients with CCs between <3 and ≥3 h of operative time (OR, 1.07; 95% CI, 0.75-1.51, p = 0.72), between the presence and absence of blood transfusion (OR, 1.60; 95% CI, 0.69-3.66, p = 0.27) and between the presence and absence of previous laparotomies (OR, 1.47; 95% CI, 0.93-2.32, p = 0.10). The examined data revealed that contaminated wounds, male sex, an American Society of Anesthesiology score ≥3 h, a body mass index ≥25, stoma creation, open surgery and diabetes mellitus are all risk factors for SSIs in patients with CC. However, operative time, blood transfusion and previous laparotomies were not found to be risk factors for SSIs in patients with CC. However, given that several comparisons had a small number of chosen research, consideration should be given to their values.

Ability of minimally invasive surgery to decrease incisional surgical site infection occurrence in patients with colorectal cancer and other gastroenterological malignancies

Background

Surgical site infection (SSI) is one of the most important complications of surgery for gastroenterological malignancies because it leads to a prolonged postoperative hospital stay and increased inpatient costs. Furthermore, SSI can delay the initiation of postoperative treatments, including adjuvant chemotherapy, negatively affecting patient prognosis. Identifying the risk factors for SSI is important to improving intra- and postoperative wound management for at-risk patients.

Methods

Patients with gastroenterological malignancies who underwent surgery at our institution were retrospectively reviewed and categorized according to the presence or absence of incisional SSI. Clinicopathological characteristics such as age, sex, body mass index, malignancy location, postoperative blood examination results, operation time, and blood loss volume were compared between groups. The same analysis was repeated of only patients with colorectal malignancies.

Results

A total of 528 patients (330 men, 198 women; mean age, 68 ± 11 years at surgery) were enrolled. The number of patients with diseases of the esophagus, stomach, small intestine, colon and rectum, liver, gallbladder, and pancreas were 25, 150, seven, 255, 51, five, and 35, respectively. Open surgery was performed in 303 patients vs. laparoscopic surgery in 225 patients. An incisional SSI occurred in 46 patients (8.7%). Multivariate logistic regression analysis showed that postoperative hyperglycemia (serum glucose level ≥140 mg/dl within 24 h after surgery), colorectal malignancy, and open surgery were independent risk factors for incisional SSI. In a subgroup analysis of patients with colorectal malignancy, incisional SSI occurred in 27 (11%) patients. Open surgery was significantly correlated with the occurrence of incisional SSI (P = 0.024).

Conclusions

Postoperative hyperglycemia and open surgery were significant risk factors for SSI in patients with gastroenterological malignancies. Minimally invasive surgery could reduce the occurrence of incisional SSI.

Controlling the controls: what is negative pressure wound therapy compared to in clinical trials?

AIM

Surgical site infections (SSIs) are common following colorectal operations. Clinical trials suggest that closed incision negative pressure wound therapy (ciNPWT) may reduce SSIs compared to a 'standard of care' group. However, wound management in the standard of care group may vary. The aim of this review was to assess the control arms in trials of ciNPWT for potential confounding variables that could influence the rates of SSI and therefore the trial outcomes.

METHODS

A mapping review of the PubMed database was undertaken in the English language for randomized controlled trials that assessed, in closed surgical wounds, the use of ciNPWT compared to standard of care with SSI as an outcome. Data regarding wound care to assess potential confounding factors that may influence SSI rates were compared between the ciNPWT and standard of care groups. Included were the method of wound closure, control dressing type, frequency of dressing changes and postoperative wound care (washing).

RESULTS

Twenty-seven trials were included in the mapping review. There was heterogeneity in ciNPWT duration. There was little control in the comparator standard of care groups with a variety of wound closure techniques and different control dressings used. Overall standard of care dressings were changed more frequently than the ciNPWT dressing and there was no control over wound care or washing. No standard for 'standard of care' was apparent.

CONCLUSION

In randomized trials assessing the intervention of ciNPWT compared to standard of care there was considerable heterogeneity in the comparator groups and no standard of care was apparent. Heterogeneity in dressing protocols for standard of care groups could introduce potential confounders impacting SSI rates. There is a need to standardize care in ciNPWT trials to assess potential meaningful differences in SSI prevention.

Trends in infectious complications after partial colectomy for colon cancer over a decade: A national cohort study

BACKGROUND

The American College of Surgeons National Surgical Quality Improvement Program helps participating hospitals track and report surgical complications with the goal of improving patient care. We sought to determine whether postoperative infectious complications after elective colectomy for malignancy improved among participating centers over time.

METHODS

Patients with colon malignancies who underwent elective partial colectomy with primary anastomosis (categorized as low or non-low) were identified from the American College of Surgeons National Surgical Quality Improvement Program database (2011-2019). Thirty-day postoperative infectious complications analyzed by year included superficial, deep, and organ space surgical site infections, urinary tract infection, pneumonia, and sepsis. Trends in patient and treatment characteristics were investigated using log-linear regression along with their association with infectious outcomes.

RESULTS

Of the 78,827 patients identified, 51% were female, and the median age was 68. The majority (84%) underwent partial colectomy without a low anastomosis. There was a decrease in all infectious complications except for organ space infections which increased 35% overall from 2.0 to 2.7% (P = .037), driven by patients without a low anastomosis (1.9%-2.7%, P = .01). There was no change in most patient factors associated with organ space infections, except for a notable increase in American Society of Anesthesiologists class III and IV-V patients over time, both associated with organ space infections (P < .001; P = .002).

CONCLUSION

Infectious complications have decreased significantly overall after colectomy for colon cancer, whereas there has been an increase in organ space infection rates specifically. Although changing patient characteristics may contribute to this observed trend, further study is needed to better understand its etiology to help mitigate this complication.

Choice of specimen's extraction site affects wound morbidity in laparoscopic colorectal cancer surgery

BACKGROUND

The choice for an ideal site of specimen extraction following laparoscopic colorectal surgery remains debatable. However, midline incision (MI) is usually employed for right and left-sided colonic resections while left iliac fossa or suprapubic transverse incision (STI) were reserved for sigmoid and rectal cancer resections.

OBJECTIVE

To compare the incidence of surgical site infection (SSI) and incisional hernia (IH) in elective laparoscopic colorectal surgery for cancer and specimen extraction via MI or STI.

METHOD

Prospectively collected data of elective laparoscopic colorectal cancer resections between January 2017 and December 2019 were retrospectively reviewed. MI was employed for right and left-sided colonic resections while STI was used for sigmoid and rectal resections. SSI is defined according to the US CDC criteria. IH was diagnosed clinically and confirmed by CT scan at 1 year.

RESULTS

A total of 168 patients underwent elective laparoscopic colorectal resections. MI was used in 90 patients while 78 patients had STI as an extraction site. Demographic and preoperative data is similar for two groups. The rate of IH was 13.3% for MI and 0% in the STI (p = 0.001). SSI was seen in 16.7% of MI vs 11.5% of STI (p = 0.34). Univariate and multivariate analysis showed that the choice of extraction site is associated with statistically significant higher incisional hernia rate.

CONCLUSION

MI for specimen extraction is associated with higher incidence of both SSI and IH. The choice of incision for extraction site is an independent predicative factor for significantly higher IH and increased SSI rates.

Incision pressing, a simple and effective intervention to reduce colorectal surgical site infection: A propensity score-matched study

Background

Colorectal surgery is associated with a high risk of surgical site infection (SSI). In March 2017, we developed an intervention, called “PRESS”, with the aim of reducing colorectal superficial SSI. This study assessed the effect of the new intervention in reducing the rates of superficial SSI in colorectal surgery.

Methods

This study was a retrospective review of 312 PRESS+ patients compared to 171 historical control PRESS− patients who were 18 years of age or older and underwent elective colorectal surgery with clean-contaminated wounds from January 2015 to June 2020. In the PRESS+ groups, we pressed the incision downward hard with clean gauze after the interrupted suturing of the skin. Propensity score matching with 15 variables was performed in a 1:1 ratio to reduce selection bias. Univariate analysis and multivariate analysis were performed to identify risk factors associated with SSI.

Results

The characteristics of the PRESS+ (n = 160) and PRESS− (n = 160) groups were well balanced after propensity score matching. The PRESS+ group had a lower superficial SSI rate (1.9% vs. 6.9%, P = 0.029) and a lower overall SSI rate (2.5% vs. 10.0%, P = 0.006) than the PRESS− group. Furthermore, multivariate analysis showed that the incisional press was an effective protective factor for superficial SSI (adjusted odds ratio = 0.215, 95% confidence interval = 0.057–0.818, P = 0.024). In addition, female sex (P = 0.048) and blood transfusion (P = 0.011) were demonstrated to be independent risk factors for superficial SSI.

Conclusion

The incisional press after suturing is a simple, costless, and effective intervention in reducing superficial incisional SSI.

Effect of Enteral Immunonutrition in Patients Undergoing Surgery for Gastrointestinal Cancer: An Updated Systematic Review and Meta-Analysis

Background

The efficacy of enteral immunonutrition (EIN) in patients undergoing gastrointestinal cancer surgery remains debatable. This meta-analysis aimed to investigate the effectiveness of EIN administration in patients undergoing surgery for gastrointestinal cancer.

Methods

From January 2000 to January 2022, PubMed, EMBASE, Cochrane Library, and Web of Science were thoroughly searched for randomized controlled trials (RCTs) with EIN versus standard diet or no supplement in patients undergoing surgery for gastrointestinal cancer. Overall complications and infectious complications were the primary outcomes. The secondary results were non-infectious complications, mortality, length of hospital stay, and enteral nutrition-related complications.

Results

Thirty-five studies reporting 3,692 patients undergoing surgery for gastrointestinal cancer (including gastric cancer, colorectal cancer, esophageal cancer, periampullary cancer, or pancreatic cancer) were included. Compared with the control group, EIN group had a significantly decreased incidence of overall complications (RR = 0.79, p < 0.001). Infectious complications in patients who received EIN were considerably lower than in the control group (RR = 0.66, p < 0.001). Compared to the control group, the incidence of surgical site infection, abdominal abscess, anastomotic leakage, bacteremia, duration of systemic inflammatory response syndrome (SIRS), and duration of antibiotic therapy was significantly lower in the specific infectious complications treated with EIN. Still, there was no significant difference between the two groups with other infectious complications. Moreover, a substantial shortening in the length of hospital stay was shown in EIN group compared with the control group. Still, no significant effect of EIN was demonstrated in non-infectious complicatios and mortality. The enteral nutrition-related complications had no significant difference between two groups.

Conclusions

EIN is safe and effective in reducing overall complications, infectious complications, and hospital stay in patients undergoing gastrointestinal cancer surgery (including gastric cancer, colorectal cancer, esophageal cancer, periampullary cancer, or pancreatic cancer).

Risk factors for surgical site infection in patients undergoing colorectal surgery: A meta-analysis of observational studies

OBJECTIVE

Surgical site infection (SSI) is the second most prevalent hospital-based infection and affects the surgical therapeutic outcomes. However, the factors of SSI are not uniform. The main purpose of this study was to understand the risk factors for the different types of SSI in patients undergoing colorectal surgery (CRS).

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched using the relevant search terms. The data extraction was independently performed by two investigators using a standardized format, following the pre-agreed criteria. Meta-analysis for the risk factors of SSI in CRS patients was carried out using Review Manager 5.3 (RevMan 5.3) and Stata 15.1 software. The quality of evidence was evaluated using total sample size, Egger's P-value, and intergroup heterogeneity, which contained three levels: high-quality (Class I), moderate-quality (Class II/III), and low-quality (Class IV). The publication bias of the included studies was assessed using funnel plots, Begg's test, and Egger's test.

RESULTS

Of the 2660 potentially eligible studies, a total of 31 studies (22 retrospective and 9 prospective cohort studies) were included in the final analysis. Eventually, the high-quality evidence confirmed that SSI was correlated with obesity (RR = 1.60, 95% confidence interval (CI): 1.47-1.74), ASA score ≥3 (RR = 1.34, 95% CI: 1.19-1.51), and emergent surgery (RR = 1.36, 95% CI: 1.19-1.55). The moderate-quality evidence showed the correlation of SSI with male sex (RR = 1.30, 95% CI: 1.14-1.49), diabetes mellitus (RR = 1.65, 95% CI: 1.24-2.20), inflammatory bowel disease (RR = 2.12, 95% CI: 1.24-3.61), wound classification >2 (RR = 2.65, 95% CI: 1.52-4.61), surgery duration ≥180 min (RR = 1.88, 95% CI: 1.49-2.36), cigarette smoking (RR = 1.38, 95% CI: 1.14-1.67), open surgery (RR = 1.81, 95% CI: 1.57-2.10), stoma formation (RR = 1.89, 95% CI: 1.28-2.78), and blood transfusion (RR = 2.03, 95% CI:1.34-3.06). Moderate-quality evidence suggested no association with respiratory comorbidity (RR = 2.62, 95% CI:0.84-8.13) and neoplasm (RR = 1.24, 95% CI:0.58-2.26). Meanwhile, the moderate-quality evidence showed that the obesity (RR = 1.28, 95% CI: 1.24-1.32) and blood transfusion (RR = 2.32, 95% CI: 1.26-4.29) were independent risk factors for organ/space SSI (OS-SSI). The high-quality evidence showed that no correlation of OS-SSI with ASA score ≥3 and stoma formation. Furthermore, the moderate-quality evidence showed that no association of OS-SSI with open surgery (RR = 1.37, 95% CI: 0.62-3.04). The high-quality evidence demonstrated that I-SSI was correlated with stoma formation (RR = 2.55, 95% CI: 1.87-3.47). There were some certain publication bias in 2 parameters based on asymmetric graphs, including diabetes mellitus and wound classification >2. The situation was corrected using the trim and fill method.

CONCLUSIONS

The understanding of these factors might make it possible to detect and treat the different types of SSI more effectively in the earlier phase and might even improve the patient's clinical prognosis. Evidence should be continuously followed up and updated, eliminating the potential publication bias. In the future, additional high-level evidence is required to verify these findings.

Outcomes of Laparoscopic vs. Open Reversal of Hartmann's Procedure: A Single Centre Experience

Introduction

Hartmann’s procedure is widely performed to fix colonic obstruction and perforation. It should ideally be followed by a reversal to restore bowel continuity. Reversal of Hartmann’s procedure was traditionally performed using an open technique. However, in recent days, the use of a laparoscopic approach has become increasingly popular. In our retrospective observational study, we aim to investigate the outcomes of laparoscopic versus open reversal of Hartmann’s procedure in a UK tertiary centre.

Methods

All patients who underwent reversal of their Hartmann’s procedure between January 2017 and December 2019 were included in the study. Data including demographics, days between primary operation and reversal, laparoscopic or open reversal, length of hospital stay following reversal procedure, 30-day readmission, mortality, and complication rate were collected. Statistical analysis was performed using t-test and chi-squared test.

Results

Forty-nine patients underwent reversal of Hartmann’s procedure from January 2017 to December 2019. The mean age of our cohort was 59.6 ± 13.2 years. There was no significant difference in baseline demographics of both groups, apart from the number of days between the primary operation and reversal procedure. There was also no statistical difference in length of stay, 30-day readmission, and mortality between laparoscopic and open reversal techniques. However, there was a higher incidence of wound complications in patients who underwent open reversal of Hartmann’s procedure.

Conclusion

The reversal of Hartmann’s procedure is a challenging operation. We found no significant difference between both open and laparoscopic approaches, but our study might be confounded by various factors including small sample size and selection bias. A larger, randomised study with greater statistical power is needed to confirm our findings.

Development of a new pharmacokinetic model for target-concentration controlled infusion of cefoxitin as a prophylactic antibiotic in colorectal surgical patients

AIMS

There are several limitations to the existing method of administering cefoxitin as a prophylactic antibiotic, and the limitations may be overcome by applying the target-concentration controlled infusion (TCI) method. Population pharmacokinetic parameters are required to administer cefoxitin by the TCI method. The aim of this study was to construct a new pharmacokinetic model of cefoxitin for the TCI method in colorectal surgical patients.

METHODS

In patients undergoing colorectal surgery, 2 g of cefoxitin was dissolved in 50 mL of saline and administered for 10 minutes prior to skin incision. Arterial blood samples were obtained at preset intervals to measure the total and free plasma concentrations of cefoxitin. Population pharmacokinetic analysis was performed using NONMEM software (ICON Development Solutions, Dublin, Ireland). Additionally, stochastic simulation was used to indirectly evaluate the effectiveness of the two administration methods (standard method vs TCI).

RESULTS

In total, 297 plasma concentration measurements from 31 patients were used to characterize the pharmacokinetics of cefoxitin. A three-compartment mammillary model described the pharmacokinetics of cefoxitin. Body weight and creatinine clearance were significant covariates for clearance. The stochastic simulation showed that when compared with the standard method, the TCI method has a significantly higher fraction of time that the free concentration of cefoxitin is maintained above the minimum inhibitory concentration (P < .001).

CONCLUSIONS

TCI has the potential to become a new infusion method for patient-tailored dosing in surgical patients. To administer cefoxitin via TCI in clinical practice, the newly constructed pharmacokinetic model should undergo proper external validation.

Risk factors for surgical site infection after colorectal resection: a prospective single centre study. An analysis on 287 consecutive elective and urgent procedures within an institutional quality improvement project

AIM

To determine the incidence and to investigate risk factors for surgical site infections (SSIs) in a cohort of patients undergoing colorectal surgery.

MATERIAL & METHODS

Data from all consecutive patients operated at our department in an elective or in an urgent setting over a 4-month period were prospectively collected and analysed. The updated Centres for Disease Control and Prevention guidelines were used to define and to score SSIs during weekly meetings. Multivariate analysis was performed considering a list of 20 potential perioperative risk factors.

RESULTS

A total of 287 patients (mean age 56.9 ± 16.8 years, 51.2% male) were included. Thirty-five patients (12.2%) developed SSI. Independent risk factors for SSI were BMI <20 kg/m² (OR 3.70; p = .022), cancer (OR 0.33; p = .046), respiratory comorbidity (OR 3.15; p = .035), presence of a preoperative stoma (OR 3.74; p = .003), and operative time ≥3 hours (OR 2.93; p = .014).

CONCLUSION

Identified incidence and risk factors for the development of SSI after colorectal surgery were consistent with those already reported in the literature. The possibility to develop a validated prediction model for SSIs warrants further investigation, in order to target specific preventive measures on high-risk population.

Wound infection in colorectal cancer resections through a laparoscopic approach: a single-center prospective observational study of over 3000 cases

OBJECTIVES

This prospective observational study aimed to clarify the incidence and independent risk factors of wound infection after laparoscopic surgery for primary colonic and rectal cancer.

METHODS

A prospective surveillance of surgical site infection (SSI) was conducted in consecutive patients with primary colorectal cancer, who underwent elective laparoscopic surgery in a single comprehensive cancer center between 2005 and 2014. The outcomes of interest were the incidence and risk factors of wound infection.

RESULTS

In total, 3170 patients were enrolled in the study. The overall incidence of wound infection was 3.0%. The incidence of wound infection was significantly higher in rectal surgery than in colonic surgery (4.7 vs. 2.1%, p < 0.001). In rectal surgery, independent risk factors for developing wound infection included abdominoperineal resection (p < 0.001, odds ratio [OR] = 11.4, 95% confidence interval [CI]: 5.04-24.8), body mass index (BMI) ≥ 25 kg/m2 (p = 0.041, OR = 1.97, 95% CI, 1.03-3.76), and chemoradiotherapy (p = 0.032, OR = 2.18, 95% CI, 1.07-4.45). In laparoscopic colonic surgery, no significant risk factors were identified.

CONCLUSIONS

Laparoscopic rectal surgery has a higher risk of wound infection than colonic surgery. Laparoscopic rectal surgery involving abdominoperineal resection, patients with higher BMI, and chemoradiotherapy requires careful observation in wound care and countermeasures against wound infection.

Update on risk factors of surgical site infection in colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

Surgical site infection (SSI) in colorectal cancer (CRC) has been a serious health care problem due to the delay of postoperative recovery. Our present study aimed to explore the risk factors for SSI in CRC patients.

METHODOLOGY

We have systematically searched these databases: PubMed, Cochrane Library, and EMBASE as of March 2020 for studies on risk factors associated with SSI. Two investigators independently conducted the quality assessment and data extraction. Related risk factors in the studies were recorded, and a meta-analysis was performed.

RESULTS

The search initially provided 2262 hits, 1913 studies were screened by two independent investigators. Finally, 15 studies were identified to be relevant for this meta-analysis. In total, 25 risk factors were eligible. Our meta-analysis indicated that eight factors (obesity, male sex, diabetes mellitus, ASA score ≥ 3, stoma creation, intraoperative complications, perioperative blood transfusion, and operation time ≥ 180 min) were significant risk factors for SSI, and one factor (laparoscopic procedure) was protective for SSI.

CONCLUSIONS

Effective interventions targeting the above factors may reduce the risk of developing postoperative SSI in CRC patients and improve the clinical outcome of patients. Further prospective studies are needed to confirm these findings.

Time-dependent displacement of commensal skin microbes by pathogens at the site of colorectal surgery

BACKGROUND

Although the healthy human skin microbiome has been the subject of recent studies, it is not known whether alterations among commensal microbes contribute to surgical site infections (SSIs). The objective of this study was to characterize temporal and spatial variation in the skin microbiota of patients undergoing colorectal surgery and to determine if dysbiosis contributes to SSIs.

METHODS

Sixty (60) adults scheduled to undergo elective colon or rectal resection were identified by convenience sampling. By analyzing bacterial 16S rRNA gene sequences isolated from clinical samples, we used a culture-independent strategy to monitor perioperative changes in microbial diversity of fecal samples and the skin.

RESULTS

990 samples were analyzed from 60 patients. Alpha diversity on the skin decreased after surgery but later recovered at the postoperative clinic visit. In most patients, we observed a transient postoperative loss of skin commensals (Corynebacterium and Propionibacterium) at the surgical site, which were replaced by potential pathogens and intestinal anaerobes (e.g. Enterobacteriaceae). These changes were not observed on skin that was uninvolved in the surgical incision (chest wall). One patient developed a wound infection. Incisional skin swabs from this patient demonstrated a sharp postoperative increase in the abundance of Enterococcus, which was also cultured from wound drainage.

CONCLUSION

We observed reproducible perioperative changes in the skin microbiome following surgery. The low incidence of SSIs in this cohort precluded analysis of associations between dysbiosis and infection. We postulate that real time monitoring of the skin microbiome could provide actionable findings about the pathogenesis of SSIs.

Prognostic Value of Surgical Site Infection in Patients After Radical Colorectal Cancer Resection

Background

This study aimed to evaluate the clinicopathological factors associated with surgical site infection (SSI) and the prognostic impact on patients after colorectal cancer (CRC) resection surgery.

Material/Methods

This retrospective study evaluated the relationships between SSI and various clinicopathological factors and prognostic outcomes in 326 consecutive patients with CRC who underwent radical resection surgery at Wuhan Union Hospital during April 2015–May 2017.

Results

Among the 326 patients who underwent radical CRC resection surgery, 65 had SSIs, and the incidence rates of incisional and organ/space SSI were 16.0% and 12.9%, respectively. Open surgery, chronic obstructive pulmonary disease (COPD), and a previous abdominal surgical history were identified as risk factors for incisional SSI. During a median follow-up of 40 months (range: 5–62 months), neither simple incisional nor simple organ/space SSI alone significantly affected disease-free survival (DFS) or overall survival (OS), whereas combined incisional and organ/space SSI had a significant negative impact on both the 3-year DFS and OS (P<0.001). A multivariate analysis identified that age ≥60 years, lymph node involvement, tumor depth (T3–T4), and incisional and organ/space SSI were independent predictors of 3-year DFS and OS. In addition, adjuvant chemotherapy and a carbohydrate antigen-125 concentration ≥37 ng/ml were also independent predictors of OS.

Conclusions

We have identified several clinicopathological factors associated with SSI, and identified incisional and organ/space SSI is an independent prognostic factor after CRC resection. Assessing the SSI classification may help to predict the prognosis of these patients and determine further treatment options.

Comparison of colonic stents, stomas and resection for obstructive left colon cancer: a meta-analysis

BACKGROUND

Emergency surgery (ES) is the standard-of-care for left-sided obstructing colon cancer, with self-expanding metallic stents (SEMSs) and diverting colostomies (DCs) being alternative approaches. The aim of this study was to review the short- and long-term outcomes of SEMS versus ES or DC.

METHODS

Embase and Medline were searched for articles comparing SEMS versus ES or DC. Primary outcomes were survival and recurrence rates. Secondary outcomes were peri- and postoperative outcomes. SEMS-specific outcomes include success and complication rates. Pooled odds ratio and 95% confidence interval were estimated with DerSimonian and Laird random effects used to account for heterogeneity.

RESULTS

Thirty-three studies were included, involving 15,224 patients in 8 randomized controlled trials and 25 observational studies. There were high technical and clinical success rates for SEMS, with low rates of complications. Our meta-analysis revealed increased odds of laparoscopic surgery and anastomosis, and decreased stoma creation with SEMS compared to ES. SEMS led to fewer complications, including anastomotic leak, wound infection, ileus, myocardial infarction, and improved 90-day in-hospital mortality. There were no significant differences in 3- and 5-year overall, cancer-specific and disease-free survival. SEMS, compared to DC, led to decreased rates of stoma creation, higher rates of ileus and reoperation, and led to longer hospital stay.

CONCLUSIONS

SEMS leads to better short-term outcomes but confers no survival advantage over ES. It is unclear whether SEMS has better short-term outcomes compared to DC. There is a lack of randomized trials with long-term outcomes for SEMS versus DC, hence results should be interpreted with caution.

Effect of laparoscopic surgery on the risk for surgical site infections in colorectal resection: results from the Health Insurance Review & Assessment Service Database

Purpose

To compare the hospital length of stay (LOS), duration of antibiotic use, medical costs, and incidence of surgical site infection (SSI) between laparoscopic colorectal surgery (Lap-CRS) and open CRS (Open-CRS).

Methods

We retrospectively reviewed data of the Health Insurance Review and Assessment Service Surgical Antibiotic Prophylaxis assessment (7th assessment, 2015); the nationwide data were collected from patients who underwent CRS from September to November 2015 in low volume hospital to the tertiary hospital level in Korea.

Results

All 2,751 patients who underwent elective CRS were assessed. The mean hospital LOS (12.18 days vs. 14.16 days, P < 0.001) and mean postoperative LOS (8.21 days vs. 9.46 days, P < 0.001) were shorter in the Lap-CRS group than in the Open-CRS group. The mean duration of antibiotic use was shorter in the Lap-CRS group (2.91 days vs. 3.64 days, P = 0.033). The rate of SSI was lower in the Lap-CRS group, but there was no significant difference between the groups (3.57% vs. 5.01%, P = 0.133). Among the SSI group, the mean LOS (19.5 days vs. 24.9 days, P = 0.081), duration of antibiotic use (12.62 days vs. 15.46 days, P = 0.097), and medical costs showed no significant difference between the 2 groups.

Conclusion

Lap-CRS is significantly associated with reduced hospital LOS and the duration of antibiotic use in this study. However, we could not identify significant differences in the incidence of SSI according to the type of surgery. To assess the overall benefits of Lap-CRS, studies including the rate of SSI up to 30 days postoperatively will be needed in the future.

Incidence of and risk factors for surgical site infection after colorectal surgery: A multiple-center prospective study of 3,663 consecutive patients in China

BACKGROUND

Surgical site infection (SSI) after colorectal surgery (CRS) remains a significant problem for its negative clinical outcomes. However, it is poorly understood in China. This study aims to investigate the incidence, risk factors and microbiology of SSI after CRS.

METHODS

A nationwide prospective multicenter design was applied. Patients in 19 Chinese hospitals from 2015 to 2018 were prospectively monitored for SSI after CRS. Demographic data, hospital characteristics, and potential perioperative risk factors were collected and analyzed, using univariate and multivariate logistic regression models.

RESULTS

Among 3,663 study participants, 134(3.66%) episodes of SSI were identified. The incidence rate of SSI decreased from 5.9 infections per 100 procedures in 2015 to 3.1 infections per 100 procedures in 2018 (incidence rate ratio, 0.52; 95% CI, 0.28-0.94). The SSI rates were 1.88, 4.15, 6.27 and 11.58 per 100 operations for the National Nosocomial Infections Surveillance system (NNIS) risk index categories of 0, 1, and 2 or 3, respectively. Escherichia coli (54/134, 40.3%) and Klebsiella pneumoniae (10/134, 7.5%) were the most frequently isolated microorganisms. A high prevalence of antibiotic resistance were observed in our study, with rates of extended spectrum beta-lactamase-producing or carbapenem-resistant Escherichia coli and Klebsiella pneumonia of 50.0%(27/54) and 30.0%(3/10) respectively. Preoperative hospital stay ≥ 48h (OR=2.28, 95% CI: 1.03-5.02, P=0.042) and contaminated or dirty wound (OR=3.38, 95% CI: 1.88-6.06, P=4.50×10^-5) were significantly associated with increasing risk of SSI after CRS.

CONCLUSION

A statistically significant but modest decrease in the incidence rate of CRS SSI over the 4-year study period was observed in this study. Noticeably, the relatively high rates of multidrug-resistant pathogens causing SSI after CRS should be alert, while more studies with large population are needed due to the small number of isolates identified in our survey.

What influences conversion to open surgery during laparoscopic colorectal resection?

INTRODUCTION

We analyzed the risk of morbidity and mortality in laparoscopic (Lap) conversion for colorectal surgery across a group of subspecialist surgeons with expertise in minimally invasive techniques.

METHODS

We reviewed prospective data patients who underwent abdominopelvic procedures from 7/1/2007 to 12/31/2016 at a tertiary care facility. We identified procedures that were converted from Lap to open (Lap converted). Lap converted procedures were matched to Lap completed and open procedures based on elective versus urgent and surgeon. We also abstracted patient demographics and outcomes at 30 days using the American College of Surgeons National Surgical Quality Improvement Program defined adverse event list. We analyzed outcomes across these groups (Lap converted, Lap completed, open procedures) with x² and t tests and used the Bonferroni Correction to account for multiple statistical testing.

RESULTS

From a database of 12,454 procedures, we identified 100 Lap converted procedures and matched them to 305 open procedures and 339 Lap completed procedures. In our dataset of abdominopelvic procedures, Lap techniques were attempted in 49 ± 1%. We noted a higher risk of aggerate morbidity following open procedures (33 ± 10) as compared to Lap converted (29 ± 17%) and the matched Lap completed procedures (18 ± 8%; p < 0.001). Converted cases had the longest operative time (222 ± 102 min), compared to lap completed (177 ± 110), and open procedures (183 ± 89). There were no differences in mortality, sepsis complications, anastomotic leaks, or unplanned returns to the operating room across the three operative groups.

CONCLUSIONS

Although aggregate morbidity of Lap converted procedures is higher than in Lap completed procedures, it remains less than in matched open procedures. Compared to Lap completed procedures, the additional morbidity of Lap converted procedures appears to be related to additional surgical site infection risk. Our data suggest that surgeons should not necessarily be influenced by additional complications associated with conversion when contemplating complex laparoscopic colorectal procedures.

Post-Operative Infection Prediction and Risk Factor Analysis in Colorectal Surgery Using Data Mining Techniques: A Pilot Study

Background: Post-operative infections have many negative consequences for patients' health and the healthcare system. Among other things, they increase the recovery time and the risk of re-admission. Also, infection results in penalties for hospitals and decreases the quality performance measures. Surgeons can take preventive actions if they can identify high-risk patients. The purpose of this study was to develop a model to help predict those patients at risk for post-operative infection. Methods: A retrospective analysis was conducted on patients with colorectal post-operative infections. Univariable analysis was used to identify the features associated with post-operative infection. Then, a support vector classification-based method was employed to select the right features and build prediction models. Decision tree, support vector machine (SVM), logistic regression, naïve Bayes, neural network, and random forest algorithms were implemented and compared to determine the performance algorithm that best predicted high-risk patients. Results: From 2016 to the first quarter of 2017, 208 patients who underwent colorectal resection were analyzed. The factors with a statistically significant association (p < 0.05) with post-operative infections were elective surgery, origin status, steroid or immunosuppressant use, >10% loss of body weight in the prior six months, serum creatinine concentration, length of stay, unplanned return to the operating room, administration of steroids or immunosuppressants for inflammatory bowel disease, use of a mechanical bowel preparation, various Current Procedural Terminology (CPT) codes, and discharge destination. However, accurate prediction models can be developed with seven factors: age, serum sodium concentration, blood urea nitrogen, hematocrit, platelet count, surgical procedure time, and length of stay. Logistic regression and SVM were stable models for predicting infections. Conclusion: The models developed using the pre-operative features along with the full list of features helped us interpret the results and determine the significant factors contributing to infections. These factors present opportunities for proper interventions to mitigate infection risks and their consequences.

Risk Factors for Surgical Site Infection After Laparoscopic Colectomy: An NSQIP Database Analysis

BACKGROUND

Surgical site infection (SSI) is a common complication after colon surgery. This study aimed to evaluate risk factors for SSI and its types in laparoscopic colectomy patients using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database.

MATERIALS AND METHODS

The NSQIP database was queried for patients undergoing laparoscopic colectomy from 2011 through 2017. Univariate analysis and multivariable logistic regression were used to evaluate risk factors associated with any SSI, superficial SSI, deep-incisional SSI, and organ-space SSI.

RESULTS

Of 72,519 patients, 4906 cases of SSI were identified: 2276 superficial SSI, 357 deep-incisional SSI, and 2483 organ-space SSI. Risk factors associated with superficial SSI were admission before procedure (adjusted odds ratio [AOR] = 1.31; 95% confidence interval [CI] 1.17-1.47; P < 0.01), smoking (AOR = 1.29; 95% CI 1.16-1.44; P < 0.01), and higher body mass index (AOR = 1.24 for every 5 kg/m² increase; 95% CI 1.20-1.27; P < 0.01). Deep-incisional SSI was associated with steroid use (AOR = 1.81; 95% CI 1.31-2.49; P < 0.01), admission before procedure (AOR = 1.66; 95% CI 1.30-2.13; P < 0.01), and smoking (AOR = 1.50; 95% CI 1.17-1.94; P < 0.01). Risk factors associated with organ-space SSI were wound class (AOR = 2.45 for class 4 versus ≤ 2; 95% CI 2.16-2.78; P < 0.01), chemotherapy within 90 d (AOR = 1.57; 95% CI 1.33-1.84; P < 0.01), and steroid use (AOR = 1.46; 95% CI 1.29-1.65; P < 0.01). Receipt of an oral antibiotic prep preoperatively was the strongest factor associated with SSI.

CONCLUSIONS

SSI types in patients undergoing laparoscopic colectomy have different risk factors. Modifiable risk factors may provide an opportunity to reduce SSI risk and its associated morbidity.

Perioperative Blood Transfusion and Occurrence of Surgical Site Infection: An Integrative Review

The aim of this integrative review was to locate, assess, and synthesize available evidence of the relationship between perioperative allogeneic blood transfusion and the occurrence of surgical site infection among adult patients undergoing elective surgery. After a comprehensive search of relevant databases and a review of the studies this yielded, we used a validated instrument to extract data from the 25 studies in our final sample. The clinical and surgical variables that were significantly and more frequently associated with the occurrence of surgical site infection among patients who received blood transfusions during the perioperative period were female sex, older age, and higher body mass index. Our findings indicate a lack of consensus on the hemoglobin levels that indicate a blood transfusion is necessary.

Effect of different carbon dioxide (CO2) insufflation for laparoscopic colorectal surgery in elderly patients: A randomized controlled trial

BACKGROUND

Evidence suggests that dry CO2 insufflation during laparoscopic colorectal surgery results in greater structural injury to the peritoneum and longer hospital stay than the use of warm, humidified CO2. We aimed to test the hypothesis that warm, humidified CO2 insufflation could reduce postoperative pain and improve recovery in laparoscopic colorectal surgery.

METHODS

One hundred fifty elderly patients undergoing laparoscopic colorectal surgery under general anesthesia from May 2017 to October 2018 were randomly divided into 3 groups. The primary outcomes were resting pain, cough pain, and consumption of sufentanil at 2, 4, 6, 12, 24, and 48 hours postoperatively. Quality of visual image, hemodynamic changes, esophageal temperature, mean skin temperature, mean body temperature, recovery time, days to first flatus and solid food intake, shivering, incidence of postoperative ileus, length of hospital stay, surgical site infections, patients and surgeon satisfaction scores, adverse events, prothrombin time, activated partial thromboplastin time, and thrombin time were recorded.

RESULTS

Group CE patients were associated with significantly higher early postoperative cough pain and sufentanil consumption than the other 2 groups (P < .05). Compared with group CE, patients in both groups WH and CF had significantly reduced intraoperative hypothermia, recovery time of PACU, days to first flatus and solid food intake, and length of hospital stay, while the satisfaction scores of both patients and surgeon were significantly higher (P < .05). Prothrombin time, activated partial thromboplastin time, and thrombin time were significantly higher in group CE from 60 minutes after pneumoperitoneum to the end of pneumoperitoneum than the other 2 groups (P < .05). The number of patients with a shivering grade of 0 was significantly lower and grade of 3 was significantly higher in group CE than in the other 2 groups (P < .05).

CONCLUSION

Use of either warm, humidified CO2 insufflations or 20°C, 0% relative humidity CO2 combined with forced-air warmer set to 38°C during insufflations can both reduce intraoperative hypothermia, dysfunction of coagulation, early postoperative cough pain, sufentanil consumption, days to first flatus, solid food intake, and length of hospital stay.

Novel Technique to Reduce the Incidence of SSI after Colorectal Surgery

SSI is a leading cause of morbidity and increases health-care cost after colorectal operations. It is a key hospital-level patient safety indicator. Previous literature has identified perioperative risk factors associated with SSI and interventions to decrease rate of infection. The purpose of this study was to evaluate the impact of blowhole closure on the rate of superficial and deep SSI. The ACS-NSQIP database was queried for patients undergoing colectomy at the University of Kentucky from 2013 to 2016. Retrospective chart review was performed to gather demographic data and perioperative variables. Wounds left open and packed were excluded. Rates of postoperative SSI were measured between the groups. One thousand eighty-three patients undergoing elective and emergent colectomy were reviewed. Nine hundred and forty-five had closed incision and 138 had blowhole closure. Patient characteristics between the groups were well matched. Patients with a blowhole closure were more likely to have an open procedure ( P = 0.037) and a higher wound class ( P < 0.001). The rate of superficial and deep SSI was 9.1 per cent in patients with a closed incision and 5.1 per cent in patients with blowhole closure ( P = 0.142). With adjustment for approach and wound class, blowhole closure decreased the incidence of SSI ( P = 0.04). There was no significant difference in morbidity or mortality. Patients undergoing elective and emergent colectomy had decreased incidence of SSI when blowhole closure was used. Given that it does not increase resource usage and its technical ease, blowhole closure should become the standard method of surgical wound closure.

Risk factors for incisional surgical site infection after elective laparoscopic colorectal surgery

BACKGROUND

Surgical site infection (SSI) is a common morbidity in patients undergoing colorectal surgery, and the focus of previous studies has primarily been on incisional SSI. Most reports thus far have focused on open surgery rather than on laparoscopic colorectal surgery (Lap CR). Therefore, the aim of the present study was to identify the risk factors for incisional SSI in patients undergoing elective Lap CR.

METHODS

This retrospective study was conducted to evaluate the occurrence and risk factors of incisional SSI for elective Lap CR. From January 2008 to June 2018, 1825 consecutive patients with a preoperative diagnosis of colorectal cancer who underwent Lap CR were analyzed at a single institution.

RESULTS

Incidence of incisional SSI was 3.3%. Postoperative hospital stay (days) was significantly longer in the incisional SSI group than in the non-incisional SSI group (8 [6-12] vs 10 [8-19], P < 0.001). Incisional SSI were significantly associated with five operative factors: blood loss (g) (P < 0.014), midline wound length (mm) (P = 0.038), suture materials (P = 0.014), suture technique (interrupted vs continuous mass closure, P = 0.003), and organ/space SSI (P = 0.041). Multivariate analysis showed that continuous mass closure (odds ratio 0.290; 95% confidence interval 0.101-0.831, P = 0.021) was the only factor independently associated with the incidence of incisional SSI.

CONCLUSIONS

Incidence of incisional SSI was comparable to that in previous reports. Continuous mass closure decreased the risk of incisional SSI in elective Lap CR.

Risk of Infectious Complications After Simultaneous Gastrointestinal and Liver Resections for Neuroendocrine Tumor Metastases

BACKGROUND

Neuroendocrine tumors (NETs) are a relatively rare category of cancers that arise in the gastrointestinal (GI) tract and other organs. Extended hepatectomies including resection of multiple organs are often necessary to achieve negative margins.

METHODS

We performed a review of patients undergoing liver resection for NET liver metastases from 2005 to 2015 using National Surgical Quality Improvement Program. We compared patients undergoing hepatectomy alone (HA) versus hepatectomy and a concomitant GI surgery procedure (colorectal, small bowel, and pancreatic) to evaluate postoperative infectious complications.

RESULTS

During the study period, 354 patients underwent liver resection for metastatic NET. Hepatectomy alone was performed in 98 patients, and concomitant GI surgery was performed in 256 patients, including 83 colorectal resections (HCCR), 68 small bowel resections, 75 distal pancreatectomies, and 35 pancreaticoduodenectomies (HCPD). Infectious complications were more likely to occur in those undergoing HCPD (60%, P < 0.001), and HCCR (32.5%, P < 0.05) than in those undergoing HA (16.3%). Patients undergoing HCPD and HCCR had a 7.69-fold and 2.52-fold increased risk of infectious complication, respectively, compared with HA after adjustment for other infection risk factors.

CONCLUSIONS

Neuroendocrine liver metastases requiring liver resection with concomitant colorectal resection or pancreaticoduodenectomy are at significantly increased risk of developing infectious complications.

The association between the increased performance of laparoscopic colon surgery and a reduced risk of surgical site infection

Purpose

Surgical site infection (SSI) is the most frequently occurring nosocomial infection. Remarkable surgical progress has recently been made in laparoscopic surgery. Therefore, our objective was to investigate the association between increased rates of laparoscopic colon surgery and SSI.

Methods

We retrospectively investigated SSI surveillance data from July 2003 to December 2015. Two university hospitals and 25 university-affiliated hospitals participated in prospective SSI surveillance. Univariate and multivariate analyses were performed to detect significant associations.

Results

We investigated 9655 colon surgeries. The year in which surgery was performed was significantly associated with the SSI rate (p = 0.0381). The rate of laparoscopic surgery gradually increased during the study period, and by 2012 it was routinely used for > 50% of colon surgeries. Laparoscopic surgery became a significant factor associated with reduced SSI rates compared with conventional open surgery once the performance rate of laparoscopic surgery reached > 50%.

Conclusions

Increasing rates of laparoscopic colon surgery tended to be associated with a reduction in the SSI risk after surgical treatment of colonic disease. The results of this study might encourage surgeons to view laparoscopic surgical techniques as an evidence-based approach for reducing the risk of SSI.

Electronic supplementary material

The online version of this article (10.1007/s00595-019-1760-1) contains supplementary material, which is available to authorized users.

Incidence of surgical site infection and risk factors in rectal surgery: A prospective cohort study

INTRODUCTION

Surgical site infection (SSI) is the main cause of nosocomial infection in Spain. The aim of this study was to analyze the incidence of SSI and to evaluate its risk factors in patients undergoing rectal surgery.

METHODS

Prospective cohort study, conducted from January 2013 to December 2016. Patient, surgical intervention and infection variables were collected. Infection rate was calculated after a maximum period of 30 days of incubation. The effect of different risk factors on infection was assessed using the odds ratio adjusted by a logistic regression model.

RESULTS

The study included 154 patients, with a mean age of 69.5±12 years. The most common comorbidities were diabetes mellitus (24.5%), chronic obstructive pulmonary disease (17%) and obesity (12.6%). The overall incidence of SSI during the follow-up period was 11.9% (CI95%: 7.8-17.9) and the most frequent microorganism was Escherichia coli (57.9%). Risk factors associated with surgical wound infection in the univariate analysis were blood transfusion, drain tubes and vasoactive drug administration (P<.05).

CONCLUSIONS

The incidence of SSI in rectal surgery was low. It is crucial to assess SSI incidence rates and to identify possible risk factors for infection. We recommend implementing surveillance and hospital control programs.

Colon and rectal surgery surgical site infection reduction bundle: To improve is to change

BACKGROUND

Despite the introduction of the Surgical Care Improvement Project, surgical site infections remain a source of morbidity. The aim of this study was to determine the value of implementing a colorectal bundle on SSI rates.

METHODS

Between 2011 and 2016 a total of 1351 patients underwent colorectal operations. Patients were grouped into pre-implementation (Group A, January 1, 2011-December 31, 2012), implementation (Group B, January 1, 2013-December 31, 2014) and post-implementation (Group C, January 1, 2015-December 31, 2016). Primary endpoints were superficial SSI, deep SSI, wound separation and total SSI.

RESULTS

After the bundle was implemented, there was a significant reduction in superficial (6.6%-4%, p < 0.05), deep (3.7%-1.1%, p < 0.05), and total SSI rates (10.9%-4.7%, p < 0.05). Comparing Group A to Group C there was a decrease in total SSI (9.4%-4.7%, p < 0.05).

CONCLUSION

Implementation of the bundle resulted in a reduction in overall SSI rates particularly as compliance increased. This study offers evidence that small changes can lead to significant decreases in surgical site infections.

Open Surgical Incisions After Colorectal Surgery Improve Quality Metrics, But Do Patients Benefit?

BACKGROUND

Surgical site infection is a frequent cause of morbidity after colorectal resection and is a quality measure for hospitals and surgeons. In an effort to reduce the risk of postoperative infections, many wounds are left open at the time of surgery for secondary or delayed primary wound closure.

OBJECTIVE

The purpose of this study was to evaluate the impact of delayed wound closure on the rate of surgical infections and resource use.

DESIGN

This retrospective propensity-matched study compared colorectal surgery patients with wounds left open with a cohort of patients with primary skin closure.

SETTINGS

The American College of Surgeons National Quality Improvement Program Participant Use file for 2014 was queried.

PATIENTS

A total of 50,212 patients who underwent elective or emergent colectomy, proctectomy, and stoma creation were included.

MAIN OUTCOME MEASURES

Rates of postoperative infections and discharge to medical facilities were measured.

RESULTS

Surgical wounds were left open in 2.9% of colorectal cases (n = 1466). Patients with skin left open were broadly higher risk, as evidenced by a significantly higher median estimated probability of 30-day mortality (3.40% vs 0.45%; p < 0.0001). After propensity matching (n = 1382 per group), there were no significant differences between baseline characteristics. Within the matched cohort, there were no differences in the rates of 30-day mortality, deep or organ space infection, or sepsis (all p > 0.05). Resource use was higher for patients with incisions left open, including longer length of stay (11 vs 10 d; p = 0.006) and higher rates of discharge to a facility (34% vs 27%; p < 0.001).

LIMITATIONS

This study was limited by its retrospective design and a large data set with a bias toward academic institutions.

CONCLUSIONS

In a well-matched colorectal cohort, secondary or delayed wound closure eliminates superficial surgical infections, but there was no decrease in deep or organ space infections. In addition, attention should be given to the possibility for increased resource use associated with open surgical incisions. See Video Abstract at http://links.lww.com/DCR/A560.

Reoperation after laparoscopic colorectal surgery. Does the laparoscopic approach have any advantages?

INTRODUCTION

The laparoscopic approach in colorectal complications is controversial because of its difficulty. However, it has been proven that it can provide advantages over open surgery. The aim of this study is to compare laparoscopic approach in reoperations for complications after colorectal surgery with the open approach taking into account the severity of the patient prior to reoperation.

METHODS

Patients who underwent laparoscopic colorectal surgery from January 2006 to December 2015 were retrospectively reviewed. Patients requiring urgent surgical procedures for complications in the postoperative period were divided in two groups: laparoscopic surgery (LS) and open surgery (OS). To control clinical severity prior to reoperation, The Mannheim Peritonitis Index (MPI) was calculated.

RESULTS

A total of 763 patients were studied, 40 required urgent surgery (24 OS/16 LS). More ileostomies were performed in the LS group (68.7% vs. 29.2%) and more colostomies in the OS group (37.5% vs. 6.2%), p<0.05. MPI was higher in OS group (27.31±6.47 [19-35] vs. 18.36±7.16 [11-24], p<0.001). Hospital stay after re-intervention, oral tolerance and surgical wound infection, were favorable in LS (p<0.05 in all cases). In patients with MPI score ≤26, laparoscopic approach showed shorter hospital stay after re-intervention, less stay in the critical care unit after re-intervention, earlier start of oral tolerance and less surgical wound infection (p<0.05).

CONCLUSIONS

A laparoscopic approach in re-intervention for complications after laparoscopic colorectal surgery associates a faster recovery reflected in a shorter hospital stay, earlier start of oral tolerance and a lower abdominal wall complication rate in patients with low severity index.

Simple Operating Room Bundle Reduces Superficial Surgical Site Infections After Major Urologic Surgery

OBJECTIVE

To reduce our superficial surgical site infection rate following major urologic surgery by implementing a simple operating room bundle.

METHODS

A simple operating room bundle was applied to all major urologic cases (cystectomy, nephrectomy, and prostatectomy) at a single tertiary referral center. The bundle included allowing skin prep to dry appropriately, changing gloves before skin closure, irrigating the wound before skin closure, and using a new separate sterile closing instrument set for skin closure. Alcohol-based preps were also introduced hospital-wide 3 months into the study period. The SSI rate was obtained from the National Surgical Quality Improvement Program (NSQIP) database.

RESULTS

The surgical site infection (SSI) rate was assessed after a 14-month study period for a total of 510 cases. Before instituting the alcohol-based prep, but after the bundle was implemented, 138 cases were analyzed over a 3-month period with an SSI rate of 0%. For the remaining 11 months with both the alcohol-based prep and the infection prevention bundle in place, the infection rate was 1.37% (7/510) as compared with 3.57% (22/615) for the 12-month period before bundle introduction, a statistically significant reduction (P = .023).

CONCLUSION

The SSI rate after major urologic surgery at 1 center was reduced after the introduction of a simple, fast, low-cost, and easily reproducible bundle into the operating room. The use of this bundle reduces SSI, which is critical for the patient and the physician in this era of public reporting and reimbursement based on outcomes.

Transumbilical abdominal incision for laparoscopic colorectal surgery does not increase the risk of postoperative surgical site infection

PURPOSE

Besides antibiotic prophylaxis, antiseptic skin preparation is an important measure to prevent surgical site infection (SSI). No reports have detailed the relationship between SSI and umbilical microflora following laparoscopic colorectal cancer with a transumbilical longitudinal incision.

METHODS

Risk factors and the rate of SSI were investigated in 453 patients who underwent laparoscopic colorectal resection over a 3-year period. Microbiological samples were collected from the umbilicus and SSI areas.

RESULTS

After laparoscopic procedure, we observed SSIs in approximately 5% of cases, with superficial SSI in 15 (3.3%) patients and organ/space SSIs 7 (1.5%). In univariate analysis, preoperative albumin (Alb) value and anastomosis of enterocolostomy were significantly associated with superficial SSI development. Also, age, blood loss, stoma, tumor site (rectum), and Hartmann/abdominal perineal resection (APR) were significant risk factors for organ/space SSI. In multivariate analysis, the preoperative Alb value was the most significant factor associated with a predisposition to superficial SSI. The bacteria detected in SSI were mostly different from those at wound closure. Antibiotic-resistant bacteria were included in organ/space SSI all cases.

CONCLUSIONS

SSI development with laparoscopic surgery reportedly occurs in about 3-15% cases. The SSI rate in this study and other reports was comparable. Using small transumbilical longitudinal incision in laparoscopic colorectal surgery is less likely to cause SSI when sufficient control measures are enacted, even though the umbilicus contains resident bacteria in abundance.

Perioperative Allogeneic Blood Transfusion Is Associated With Surgical Site Infection After Abdominoperineal Resection-a Space for the Implementation of Patient Blood Management Strategies

Allogeneic blood transfusion (ABT) has been reported as a major risk factor for surgical site infection (SSI) in patients undergoing colorectal surgery. However, the association of ABT with SSI in patients undergoing abdominoperineal resection (APR) and total pelvic exenteration (TPE) still remains to be evaluated. Here, we aim to elucidate this association. The medical records of all patients undergoing APR and TPE at our institution in the period between January 2000 and December 2012 were reviewed. Patients without SSI (no SSI group) were compared with patients who developed SSI (SSI group), in terms of clinicopathologic features, including ABT. In addition, data for 262 patients who underwent transabdominal rectal resection at our institution in the same period were also enrolled, and their data on differential leukocyte counts were evaluated. Multivariate analysis showed that intraoperative transfusion was an independent predictive factor for SSI after APR and TPE (P = 0.004). In addition, the first-operative day lymphocyte count of patients undergoing APR, TPE, and transabdominal rectal resection was significantly higher in nontransfusion patients compared with transfusion ones (P = 0.026). ABT in the perioperative period of APR and TPE may have an important immunomodulatory effect, leading to an increased incidence of SSI. This fact should be carefully considered, and efforts to avoid allogeneic blood exposure while still achieving adequate patient blood management would be very important for patients undergoing APR and TPE as well.

Differences in surgical site infection between laparoscopic colon and rectal surgeries: sub-analysis of a multicenter randomized controlled trial (Japan-Multinational Trial Organization PREV 07-01)

BACKGROUND

The incidence of surgical site infection (SSI) is reportedly lower in laparoscopic colorectal surgery than in open surgery, but data on the difference in SSI incidence between colon and rectal laparoscopic surgeries are limited.

METHODS

The incidence and risk factors for SSI, and the effect of oral antibiotics in colon and rectal laparoscopic surgeries, were investigated as a sub-analysis of the JMTO-PREV-07-01 (a multicenter, randomized, controlled trial of oral/parenteral vs. parenteral antibiotic prophylaxis in elective laparoscopic colorectal surgery).

RESULTS

A total of 582 elective laparoscopic colorectal resections, comprising 376 colon surgeries and 206 rectal surgeries, were registered. The incidence of SSI in rectal surgery was significantly higher than in colon surgery (14 vs. 8.2 %, P = 0.041). Although the incidence of incisional SSI was almost identical (7 %) between the surgeries, the incidence of organ/space SSI in rectal surgery was significantly higher than in colon surgery (6.3 vs. 1.1 %, P = 0.0006). The lack of oral antibiotics was significantly associated with the development of SSI in colon surgery. Male sex, stage IV cancer, and abdominoperineal resection were significantly associated with SSI in rectal surgery. The combination of oral and parenteral antibiotics significantly reduced the overall incidence of SSI in colon surgery (relative risk 0.41, 95 % confidence interval 0.19-0.86).

CONCLUSION

The incidence of SSI in laparoscopic rectal surgery was higher than in colon surgery because of the higher incidence of organ/space SSI in rectal surgery. The risk factors for SSIs and the effect of oral antibiotics differed between these two procedures.

Advantages of laparoscopic compared to conventional surgery are not related to an innate immune response of peritoneal immune activation: an animal study in rats

PURPOSE

Laparoscopic surgery (LS) has proved superior compared to conventional surgery (CS) regarding morbidity, length of hospital stay, rate of wound infection and time until recovery. An improved preservation of the postoperative immune function is assumed to contribute to these benefits though the role of the local peritoneal immune response is still poorly understood. Our study investigates the peritoneal immune response subsequent to abdominal surgery and compares it between laparoscopic and conventional surgery to find an immunological explanation for the clinically proven benefits of LS.

METHODS

Wistar rats (N = 140) underwent laparoscopic cecum resection (LCR; N = 28), conventional cecum resection (CCR; N = 28), laparoscopic sham operation (LSO; N = 28), conventional sham operation (CSO; N = 28), or no surgical treatment (CTRL; N = 28). Postoperatively, peritoneal lavages were performed, leukocytes isolated and analyzed regarding immune function and phagocytosis activity.

RESULTS

Immune function was inhibited postoperatively in animals undergoing LCR or CCR compared to CTRL reflected by a lower TNF-α (CTRL 3956.65 pg/ml, LCR 2018.48 pg/ml (p = 0.023), CCR 2793.78 pg/ml (n.s.)) and IL-6 secretion (CTRL 625.84 pg/ml, LCR 142.84 pg/ml (p = 0.009), CCR 169.53 pg/ml (p = 0.01)). Phagocytosis was not affected in rats undergoing any kind of surgery compared to CTRL. Neither cytokine secretion nor phagocytosis activity differed significantly between laparoscopic and conventional surgery.

CONCLUSIONS

According to our findings the benefits associated with LS compared to CS cannot be explained by differences in the postoperative peritoneal innate immune response. Further studies are needed to elucidate the causes for a more favorable postoperative outcome in patients after LS compared to CS.

Impact of the Specific Extraction-Site Location on the Risk of Incisional Hernia After Laparoscopic Colorectal Resection

BACKGROUND

The impact of the specific incision used for specimen extraction during laparoscopic colorectal surgery on incisional hernia rates relative to other contributing factors remains unclear.

OBJECTIVE

This study aimed to assess the relationship between extraction-site location and incisional hernia after laparoscopic colorectal surgery.

DESIGN

This was a retrospective cohort study (January 2000 through December 2011).

SETTINGS

The study was conducted at a high-volume, specialized colorectal surgery department.

PATIENTS

All of the patients undergoing elective laparoscopic colorectal resection were identified from our prospectively maintained institutional database.

MAIN OUTCOME MEASURES

Extraction-site and port-site incisional hernias clinically detected by physician or detected on CT scan were collected. Converted cases, defined as the use of a midline incision to perform the operation, were kept in the intent-to-treat analysis. Specific extraction-site groups were compared, and other relevant factors associated with incisional hernia rates were also evaluated with univariate and multivariate analyses.

RESULTS

A total of 2148 patients (54.0% with abdominal and 46.0% with pelvic operations) with a mean age of 51.7 ± 18.2 years (52% women) were reviewed. Used extraction sites were infraumbilical midline (23.7%), stoma site/right or left lower quadrant (15%), periumbilical midline (22.5%), and Pfannenstiel (29.6%) and midline converted (9.2%). Overall crude extraction site incisional hernia rate during a mean follow-up of 5.9 ± 3.0 years was 7.2% (n = 155). Extraction-site incisional hernia crude rates were highest after periumbilical midline (12.6%) and a midline incision used for conversion to open surgery (12.0%). Independent factors associated with extraction-site incisional hernia were any extraction sites compared with Pfannenstiel (periumbilical midline HR = 12.7; midline converted HR = 13.1; stoma site HR = 28.4; p < 0.001 for each), increased BMI (HR = 1.23; p = 0.002), synchronous port-site hernias (HR = 3.66; p < 0.001), and postoperative superficial surgical-site infection (HR = 2.11; p < 0.001).

LIMITATIONS

This study was limited by its retrospective nature, incisional hernia diagnoses based on clinical examination, and heterogeneous surgical population.

CONCLUSIONS

Preferential extraction sites to minimize incisional hernia rates should be Pfannenstiel or incisions off the midline. Midline incisions should be avoided when possible.

Simple, Safe, and Cost-Effective Technique for Resected Stomach Extraction in Laparoscopic Sleeve Gastrectomy

Background. Laparoscopic sleeve gastrectomy (LSG) has become a popular operation during the recent years. This procedure requires resection of 80–90% of the stomach. Extraction of gastric specimen is known to be a challenging and costly stage of the operation. In this paper, we report results of a simple and cost-effective specimen extraction technique which was applied to 137 consecutive LSG patients. Methods. Between October 2013 and October 2015, 137 laparoscopic sleeve gastrectomy surgeries were performed at Dokuz Eylul University General Surgery Department, Upper Gastrointestinal Surgery Unit. All specimens were extracted through a 15 mm trocar site without using any special device. Results. We noticed one superficial incisional surgical site infection and treated this patient with oral antibiotics. No cases of trocar site hernia were observed. Conclusion. Different techniques have been described for specimen extraction. This simple technique allows extraction of specimen safely in a short time and does not require any special device.

Malignancy is a risk factor for postoperative infectious complications after elective colorectal resection

PURPOSE

Patient and technical factors influencing the postoperative infectious complications (ICs) after elective colorectal resections are satisfactorily described. However, the underlying disease-related factors have not been extensively evaluated. This study aimed to measure the effect of malignancy on postoperative surgical site and extra surgical site infections after elective colorectal resection.

METHODS

This study is a bicentric retrospective matched pair study of prospectively gathered data. Between 2004 and 2013, 1104 consecutive patients underwent colorectal resection in two centers. Patients undergoing elective resection with supraperitoneal anastomosis for benign diseases (excluding inflammatory bowel disease) (group B, n = 305) were matched to randomly selected patients with malignancy (group M, n = 305). The matching variables were age, gender, American Society of Anesthesiologists (ASA) score, malnutrition, type of resection, and surgical approach. We compared the 30-day IC rates between patients with benign diseases (group B) and malignancy (group M). Multivariate logistic regression analysis was performed to identify the risk factors for ICs.

RESULTS

Group M had a higher overall rate of IC (25.6 vs 16.1 %, P = 0.004) as well as a higher risk of extra surgical site infections (P = 0.007) and anastomotic leakage (P = 0.039). The independent risk factors for ICs were malignancy (odds ratio (OR) = 2.02; P = 0.002), age ≥70 years (OR = 1.73, P = 0.018), tobacco history (OR = 1.87; P = 0.030), and obesity (OR = 1.68; P = 0.039).

CONCLUSION

Malignancy, age, tobacco history, and obesity increase the risk of ICs after colorectal resection. Improvement of the modifiable risk factors, increased compliance with an enhanced recovery after surgery (ERAS) program in the overall population, and optimization of immune function in patients with malignancy should be considered.

Risk factors for surgical site infection following colorectal resection: a multi-institutional study

INTRODUCTION

Surgical site infection (SSI) is an infection occurring in an incisional wound within 30 days of surgery and significantly affects patients undergoing colorectal surgery. This study examined a multi-institutional dataset to determine risk factors for SSI following colorectal resection.

METHODS

Data on 386 patients who underwent colorectal resection in three institutions were accrued. Patients were identified using a prospective SSI database and hospital records. Data are presented as median (interquartile range), and logistic regression analysis was used to identify risk factors.

RESULTS

Patients (21.5%) developed a postoperative SSI. The median time to the development of SSI was 7 days (5-10). Of all infections, 67.5% were superficial, 22.9% were deep and 9.6% were organ space. In univariate analysis, an ASA grade of II (RR 0.6, CI 0.3-0.9, P = 0.019), having an elective procedure (RR 0.4, CI 0.2-0.6, P < 0.001), using a laparoscopic approach (RR 0.5, CI 0.3-0.9, P = 0.019), having a daytime procedure (RR 0.3, CI 0.1-0.7, P = 0.006) and having a clean/contaminated wound (RR 0.4, CI 0.2-0.7, P = 0.001) were associated with reduced risk of SSI. In multivariate analysis, an ASA grade of IV (RR 3.9, CI 1.1-13.7, P = 0.034), a procedure duration over 3 h (RR 4.3, CI 2.3-8.2, P < 0.001) and undergoing a panproctocolectomy (RR 6.5, CI 1.0-40.9, P = 0.044) were independent risk factors for SSI. Those who developed an SSI had a longer duration of inpatient stay (22 days [16-31] vs 15 days [10-26], P < 0.001).

CONCLUSIONS

Patients who develop an SSI have a longer duration of inpatient stay. Independent risk factors for SSI following colorectal resection include being ASA grade IV, having a procedure duration over 3 h, and undergoing a panproctocolectomy.

Laparoscopic vs open partial colectomy in elderly patients: Insights from the American College of Surgeons - National Surgical Quality Improvement Program database

AIM

To compare the outcomes between the laparoscopic and open approaches for partial colectomy in elderly patients aged 65 years and over using the American College of Surgeons - National Surgical Quality Improvement Program (ACS NSQIP) database.

METHODS

The ACS NSQIP database for the years 2005-2011 was queried for all patients 65 years and above who underwent partial colectomy. 1:1 propensity score matching using the nearest- neighbor method was performed to ensure both groups had similar pre-operative comorbidities. Outcomes including post-operative complications, length of stay and mortality were compared between the laparoscopic and open groups. χ(2) and Fisher's exact test were used for discrete variables and Student's t-test for continuous variables. P < 0.05 was considered significant and odds ratios with 95%CI were reported when applicable.

RESULTS

The total number of patients in the ACS NSQIP database of the years 2005-2011 was 1777035. We identified 27604 elderly patients who underwent partial colectomy with complete data sets. 12009 (43%) of the cases were done laparoscopically and 15595 (57%) were done with open. After propensity score matching, there were 11008 patients each in the laparoscopic (LC) and open colectomy (OC) cohorts. The laparoscopic approach had lower post-operative complications (LC 15.2%, OC 23.8%, P < 0.001), shorter length of stay (LC 6.61 d, OC 9.62 d, P < 0.001) and lower mortality (LC 1.6%, OC 2.9%, P < 0.001).

CONCLUSION

Even after propensity score matching, elderly patients in the ACS NSQIP database having a laparoscopic partial colectomy had better outcomes than those having open colectomies. In the absence of specific contraindications, elderly patients requiring a partial colectomy should be offered the laparoscopic approach.

Laparoscopic versus open Hartmann's reversal: a systematic review and meta-analysis

BACKGROUND

Hartmann's reversal is a major surgical procedure with consistent morbidity and mortality rates. Laparoscopy has been extensively applied to colorectal surgery providing significant benefits on short- and long-term outcomes. We performed a meta-analysis of the current evidence comparing the short-term outcomes of laparoscopic Hartmann's reversal (LHR) to open Hartmann's reversal (OHR).

METHODS

A systematic search of Medline, Scopus, Web of Science, Embase, and the Cochrane database was performed. Comparative studies reporting short-term outcomes of LHR versus OHR with an intention-to-treat analysis were considered for eligibility. Primary outcome was 30-day morbidity. Secondary outcomes were 30-day mortality, 30-day reoperations, length of hospital stay (LOS), operating time, and estimated blood loss.

RESULTS

Thirteen studies comparing 862 patients (403 LHR vs 459 OHR) were included. There was no difference in mortality, while LHR was associated with a reduced overall postoperative 30-day morbidity (OR, 0.24; 95 % CI, 0.16 to 0.34). Wound infections (OR, 0.54; 95 % CI, 0.35 to 0.85) and ileus (OR, 0.47; 95 % CI, 0.25 to 0.87) were more common after OHR. LOS was shorter in the laparoscopic group as it was the time to flatus. Meta-regression analysis showed that the results were independent from potential effect modifiers.

CONCLUSIONS

LHR has less short-term complications than OHR in terms of overall morbidity, wound infection, and postoperative ileus. LOS is shorter in the LHR group, while no significant difference exists in the operating time. Randomized controlled trials are needed to confirm these findings on unbiased populations.

Daily Incision Cleansing with Alcohol Reduces the Rate of Surgical Site Infections: A Pilot Study

Surgical site infections (SSIs) represent a significant source of preventable patient morbidity and hospital expense. Our objective was to assess the role of postoperative incisional alcohol cleansing in decreasing the rates of SSI as compared with standard care (control). Patients undergoing clean-contaminated abdominal operations at a single center were included. Prospectively collected data on control patients were compared with patients treated with daily postoperative alcohol-based surgical site cleansing (70% isopropyl alcohol) for the primary outcome of an SSI within the first 30 postoperative days. A total of 93 patients were included, 56 managed with standard care and 37 managed with the addition of daily alcohol cleansing. A significantly lower rate of SSI in the group managed with daily alcohol cleansing was observed (13% vs 32%, P = 0.04). This study suggests a role for adding daily incisional alcohol cleansing to further reduce the rate of SSIs.

Single-incision laparoscopic surgery for diverticulitis in overweight patients

AIM

Single-incision laparoscopic surgery (SILS) has been introduced as a new technique for the treatment of various colorectal diseases. Recurrent or complicated diverticulitis of the sigmoid colon is a frequent indication for minimally invasive sigmoid colectomy. The aim of this study was to investigate the impact of obesity on the outcome of SILS sigmoid colectomy.

METHODS

From September 2009 to October 2014, data from 377 patients who had intended SILS sigmoid colectomy for diverticulitis at our institution were collected in a prospective database. The patients were categorized in the following subgroups: group 1 (normal weight, body mass index (BMI) < 25 kg/m(2)), group 2 (overweight, BMI 25-29.9 kg/m(2)), group 3 (obesity, BMI 30-34.9 kg/m(2)), and group 4 (morbid obesity, BMI > 35 kg/m(2)).

RESULTS

The groups were equivalent for sex, age, status of diverticulitis, the presence of acute inflammation in the specimen, and the percentage of teaching operations, but the percentage of patients with accompanying diseases was significantly more frequent in groups 2, 3, and 4 (p = 0.04, 0.008, and 0.018, respectively). As compared to group 1, the conversion rate was significantly increased in groups 2 and 4 (2.3 vs. 9.3% (p = 0.013) and 2.3 vs. 12.5% (p = 0.017), respectively). The duration of surgery, hospitalization, and morbidity did not differ between the four groups.

CONCLUSION

Up to a body mass index of 35 kg/m(2), increased body weight does not significantly reduce the feasibility and outcome of single-incision laparoscopic surgery for diverticulitis.

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.