Development of a Risk Score to Predict Anastomotic Leak After Left-Sided Colectomy: Which Patients Warrant Diversion?

Automated Identification of Postoperative Infections to Allow Prediction and Surveillance Based on Electronic Health Record Data: Scoping Review

BACKGROUND

Postoperative infections remain a crucial challenge in health care, resulting in high morbidity, mortality, and costs. Accurate identification and labeling of patients with postoperative bacterial infections is crucial for developing prediction models, validating biomarkers, and implementing surveillance systems in clinical practice.

OBJECTIVE

This scoping review aimed to explore methods for identifying patients with postoperative infections using electronic health record (EHR) data to go beyond the reference standard of manual chart review.

METHODS

We performed a systematic search strategy across PubMed, Embase, Web of Science (Core Collection), the Cochrane Library, and Emcare (Ovid), targeting studies addressing the prediction and fully automated surveillance (ie, without manual check) of diverse bacterial infections in the postoperative setting. For prediction modeling studies, we assessed the labeling methods used, categorizing them as either manual or automated. We evaluated the different types of EHR data needed for the surveillance and labeling of postoperative infections, as well as the performance of fully automated surveillance systems compared with manual chart review.

RESULTS

We identified 75 different methods and definitions used to identify patients with postoperative infections in studies published between 2003 and 2023. Manual labeling was the predominant method in prediction modeling research, 65% (49/75) of the identified methods use structured data, and 45% (34/75) use free text and clinical notes as one of their data sources. Fully automated surveillance systems should be used with caution because the reported positive predictive values are between 0.31 and 0.76.

CONCLUSIONS

There is currently no evidence to support fully automated labeling and identification of patients with infections based solely on structured EHR data. Future research should focus on defining uniform definitions, as well as prioritizing the development of more scalable, automated methods for infection detection using structured EHR data.

Anastomotic leak rate following the implementation of a powered circular stapler in elective colorectal surgeries: a retrospective cohort study

BACKGROUND

The objective of this study was to compare the anastomotic leak rates between powered and manual circular staplers in elective left-sided colorectal resections.

METHODS

A retrospective cohort study of elective left-sided colorectal resections before and after implementation of a powered circular stapler at a tertiary care center was conducted. The manual stapler group consisted of consecutive resections performed between January 2016 to December 2016 and the powered stapler group, between September 2021 and December 2022. Primary outcome was 30-day anastomotic leak rate. A chi-squared analysis was performed to compare anastomotic leak rates. Factors associated with anastomotic leak were examined.

RESULTS

Two-hundred forty-seven patients were included: 154 in the manual stapler group and 93 in the powered stapler group. Mean (SD) age was 60 (15) years old, 37.7% were female and 72.9% of resections were performed for malignancy. Both groups had similar patient characteristics and surgical technique. Overall leak rate was 2.0% in the manual stapler group and 10.8% in the powered stapler group. The powered staplers were found to have 6.06 times the odds of leak compared to manual staplers (95% CI, 1.62-22.65; p = 0.01). None of the other factors were found to be associated with anastomotic leak.

CONCLUSIONS

Patients who had left-sided colorectal anastomosis had higher anastomotic leak rates with powered compared to manual circular staplers. This finding is contrary to previous retrospective studies that found lower leak rates with powered staplers.

Stenosis of the colorectal anastomosis after surgery for diverticulitis: A national retrospective cohort study

AIM

The aim of this work was to investigate the association between early postoperative anastomotic leakage or pelvic abscess (AL/PA) and symptomatic anastomotic stenosis (SAS) in patients after surgery for left colonic diverticulitis.

METHOD

This is a retrospective study based on a national cohort of diverticulitis surgery patients carried out by the Association Française de Chirurgie. The assessment was performed using path analyses. The database included 7053 patients operated on for colonic diverticulitis, with surgery performed electively or in an emergency, by open access or laparoscopically. Patients were excluded from the study analysis where there was (i) right-sided diverticulitis (the initial database included all consecutive patients operated on for colonic diverticulitis), (ii) no anastomosis was performed during the first procedure or (iii) missing information about stenosis, postoperative abscess or anastomotic leakage.

RESULTS

Of the 4441 patients who were included in the final analysis, AL/PA occurred in 327 (4.6%) and SAS occurred in 82 (1.8%). AL/PA was a significant independent factor associated with a risk for occurrence of SAS (OR = 3.41, 95% CI = 1.75-6.66), as was the case for diverting stoma for ≥100 days (OR = 2.77, 95% CI = 1.32-5.82), while central vessel ligation proximal to the inferior mesenteric artery was associated with a reduced risk (OR = 0.41; 95% CI = 0.19-0.88). Diverting stoma created for <100 days or ≥100 days was also a factor associated with a risk for AL/PA (OR = 3.08, 95% CI = 2-4.75 and OR = 12.95, 95% CI = 9.11-18.50). Interestingly, no significant association between radiological drainage or surgical management of AL/PA and SAS could be highlighted.

CONCLUSION

AL/PA was an independent factor associated with the risk for SAS. The treatment of AL/PA was not associated with the occurrence of anastomotic stenosis. Diverting stoma was associated with an increased risk of both AL/PA and SAS, especially if it was left for ≥100 days. Physicians must be aware of this information in order to decide on the best course of action when creating a stoma during elective or emergency surgery.

Stoma associated complications after diverting loop ileostomy, end ileostomy or split stoma formation after right sided colectomy-a retrospective cohort study (StoComSplit Analysis)

BACKGROUND

For high-risk patients receiving right-sided colectomy, stoma formation is a safety strategy. Options are anastomosis with loop ileostomy, end ileostomy, or split stoma. The aim is to compare the outcome of these three options.

METHODS

This retrospective cohort study included all patients who underwent right sided colectomy and stoma formation between January 2008 and December 2021 at two tertial referral centers in Switzerland. The primary outcome was the stoma associated complication rate within one year.

RESULTS

A total of 116 patients were included. A total of 20 patients (17%) underwent primary anastomosis with loop ileostomy (PA group), 29 (25%) received an end ileostomy (ES group) and 67 (58%) received a split stoma (SS group). Stoma associated complication rate was 43% (n = 21) in PA and in ES group and 50% (n = 34) in SS group (n.s.). A total of 30% (n = 6) of patients in PA group needed reoperations, whereas 59% (n = 17) in ES and 58% (n = 39) in SS group had reoperations (P = 0.07). Wound infections occurred in 15% (n = 3) in PA, in 10% (n = 3) in ES, and in 30% (n = 20) in SS group (P = 0.08). A total of 13 patients (65%) in PA, 7 (24%) in ES, and 29 (43%) in SS group achieved stoma closure (P = 0.02). A total of 5 patients (38%) in PA group, 2 (15%) in ES, and 22 patients (67%) in SS group had a stoma-associated rehospitalization (P < 0.01).

CONCLUSION

Primary anastomosis and loop ileostomy may be an option for selected patients. Patients with end ileostomies have fewer stoma-related readmissions than those with a split stoma, but they have a lower rate of stoma closure.

CLINICAL TRIAL REGISTRATION

Trial not registered.

Score prediction of anastomotic leak in colorectal surgery: a systematic review

OBJECTIVE

Predicting the risk of anastomotic leak (AL) is of importance when defining the optimal surgical strategy in colorectal surgery. Our objective was to perform a systematic review of existing scores in the field.

METHODS

We followed the PRISMA checklist (S1 Checklist). Medline, Cochrane Central and Embase were searched for observational studies reporting on scores predicting AL after the creation of a colorectal anastomosis. Studies reporting only validation of existing scores and/or scores based on post-operative variables were excluded. PRISMA 2020 recommendations were followed. Qualitative analysis was performed.

RESULTS

Eight hundred articles were identified. Seven hundred and ninety-one articles were excluded after title/abstract and full-text screening, leaving nine studies for analysis. Scores notably included the Colon Leakage Score, the modified Colon Leakage Score, the REAL score, www.anastomoticleak.com and the PROCOLE score. Four studies (44.4%) included more than 1.000 patients and one extracted data from existing studies (meta-analysis of risk factors). Scores included the following pre-operative variables: age (44.4%), sex (77.8%), ASA score (66.6%), BMI (33.3%), diabetes (22.2%), respiratory comorbidity (22.2%), cardiovascular comorbidity (11.1%), liver comorbidity (11.1%), weight loss (11.1%), smoking (33.3%), alcohol consumption (33.3%), steroid consumption (33.3%), neo-adjuvant treatment (44.9%), anticoagulation (11.1%), hematocrit concentration (22.2%), total proteins concentration (11.1%), white blood cell count (11.1%), albumin concentration (11.1%), distance from the anal verge (77.8%), number of hospital beds (11.1%), pre-operative bowel preparation (11.1%) and indication for surgery (11.1%). Scores included the following peri-operative variables: emergency surgery (22.2%), surgical approach (22.2%), duration of surgery (66.6%), blood loss/transfusion (55.6%), additional procedure (33.3%), operative complication (22.2%), wound contamination class (1.11%), mechanical anastomosis (1.11%) and experience of the surgeon (11.1%). Five studies (55.6%) reported the area under the curve (AUC) of the scores, and four (44.4%) included a validation set.

CONCLUSION

Existing scores are heterogeneous in the identification of pre-operative variables allowing predicting AL. A majority of scores was established from small cohorts of patients which, considering the low incidence of AL, might lead to miss potential predictors of AL. AUC is seldom reported. We recommend that new scores to predict the risk of AL in colorectal surgery to be based on large cohorts of patients, to include a validation set and to report the AUC.

Risk factors for surgical site infections and trends in skin closure technique after diverting loop ileostomy reversal: A multi-institutional analysis

BACKGROUND

Surgical site infections (SSIs) are one of the most common complications following diverting loop ileostomy (DLI) closures. This study assesses SSIs after DLI closure and the temporal trends in skin closure technique.

METHODS

A retrospective review was conducted using the American College of Surgeons National Surgical Quality Improvement Program database for adult patients who underwent a DLI closure between 2012 and 2021 across a multistate health system. Skin closure technique was categorized as primary, primary ​+ ​drain, or purse-string closure. The primary outcome was SSI at the former DLI site.

RESULTS

A SSI was diagnosed in 5.7% of patients; 6.9% for primary closure, 5.7% for primary closure ​+ ​drain, and 2.7% for purse-string closure (p ​= ​0.25). A diagnosis of Crohn's disease, diverticular disease, and increasing operative time were significant risk factors for SSIs. There was a positive trend in the use of purse-string closure over time (p ​< ​0.0001).

CONCLUSIONS

This study identified a low SSI rate after DLI closure which did not vary significantly based on skin closure technique. Utilization of purse-string closure increased over time.

Systematic review of preoperative and intraoperative colorectal Anastomotic Leak Prediction Scores (ALPS)

OBJECTIVE

To systematically review preoperative and intraoperative Anastomotic Leak Prediction Scores (ALPS) and validation studies to evaluate performance and utility in surgical decision-making. Anastomotic leak (AL) is the most feared complication of colorectal surgery. Individualised leak risk could guide anastomosis and/or diverting stoma.

METHODS

Systematic search of Ovid MEDLINE and Embase databases, 30 October 2020, identified existing ALPS and validation studies. All records including >1 risk factor, used to develop new, or to validate existing models for preoperative or intraoperative use to predict colorectal AL, were selected. Data extraction followed CHecklist for critical Appraisal and data extraction for systematic Reviews of prediction Modelling Studies guidelines. Models were assessed for applicability for surgical decision-making and risk of bias using Prediction model Risk Of Bias ASsessment Tool.

RESULTS

34 studies were identified containing 31 individual ALPS (12 colonic/colorectal, 19 rectal) and 6 papers with validation studies only. Development dataset patient populations were heterogeneous in terms of numbers, indication for surgery, urgency and stoma inclusion. Heterogeneity precluded meta-analysis. Definitions and timeframe for AL were available in only 22 and 11 ALPS, respectively. 26/31 studies used some form of multivariable logistic regression in their modelling. Models included 3-33 individual predictors. 27/31 studies reported model discrimination performance but just 18/31 reported calibration. 15/31 ALPS were reported with external validation, 9/31 with internal validation alone and 4 published without any validation. 27/31 ALPS and every validation study were scored high risk of bias in model analysis.

CONCLUSIONS

Poor reporting practices and methodological shortcomings limit wider adoption of published ALPS. Several models appear to perform well in discriminating patients at highest AL risk but all raise concerns over risk of bias, and nearly all over wider applicability. Large-scale, precisely reported external validation studies are required.

PROSPERO REGISTRATION NUMBER

CRD42020164804.

Smoking Cessation for Preoperative Optimization

Cigarette smoking is associated with pulmonary and cardiovascular disease and confers increased postoperative morbidity and mortality. Smoking cessation in the weeks before surgery can mitigate these risks, and surgeons should screen patients for smoking before a scheduled operation so that appropriate smoking cessation education and resources can be given. Interventions that combine nicotine replacement therapy, pharmacotherapy, and counseling are effective to achieve durable smoking cessation. When trying to stop smoking in the preoperative period, surgical patients experience much higher than average cessation rates compared with the general population, indicating that the time around surgery is ripe for motivating and sustaining behavior change. This chapter summarizes the impact of smoking on postoperative outcomes in abdominal and colorectal surgery, the benefits of smoking cessation, and the impact of interventions aimed to reduce smoking before surgery.

Development and Validation of Machine Learning Models to Predict Readmission After Colorectal Surgery

BACKGROUND

Readmission after colorectal surgery is common and often implies complications for patients and costs for hospitals. Previous works have created predictive models using logistic regression for this outcome but have shown limited accuracy. Machine learning has shown promise in improving predictions by identifying non-linear patterns in data. We sought to create a more accurate predictive model for readmission after colorectal surgery using machine learning.

METHODS

Patients who underwent colorectal surgery were identified in the National Quality Improvement Program (NSQIP) database including years 2012-2019 and split into training, validation, and test sets. The primary outcome was readmission within 30 days of surgery. Three types of machine learning models were created, including random forest (RF), gradient boosting (XGB), and neural network (NN). A logistic regression (LR) model was also created for comparison. Model performance was evaluated using area under the receiver operating characteristic curve (AUROC).

RESULTS

The dataset included 213,827 patients after application of exclusion criteria. A total of 23,083 (10.8%) of patients experienced readmission. NN obtained an AUROC of 0.751 (95% CI 0.743-0.759), compared with 0.684 (95% CI 0.676-0.693) for LR. RF and XGB performed similarly with AUROCs of 0.749 (95% CI 0.741-0.757) and 0.745 (95% CI 0.737-0.753) respectively. Ileus, index admission length of stay, organ-space surgical site infection present at time of surgery, and ostomy placement were identified as the most contributory variables.

CONCLUSIONS

Machine learning approaches outperformed traditional statistical methods in the prediction of readmission after colorectal surgery. After external validation, this improved prediction model could be used to target interventions to reduce readmission rate.

Differential Performance of Machine Learning Models in Prediction of Procedure-Specific Outcomes

BACKGROUND

Procedure-specific complications can have devastating consequences. Machine learning-based tools have the potential to outperform traditional statistical modeling in predicting their risk and guiding decision-making. We sought to develop and compare deep neural network (NN) models, a type of machine learning, to logistic regression (LR) for predicting anastomotic leak after colectomy, bile leak after hepatectomy, and pancreatic fistula after pancreaticoduodenectomy (PD).

METHODS

The colectomy, hepatectomy, and PD National Surgical Quality Improvement Program (NSQIP) databases were analyzed. Each dataset was split into training, validation, and testing sets in a 60/20/20 ratio, with fivefold cross-validation. Models were created using NN and LR for each outcome. Models were evaluated primarily with area under the receiver operating characteristic curve (AUROC).

RESULTS

A total of 197,488 patients were included for colectomy, 25,403 for hepatectomy, and 23,333 for PD. For anastomotic leak, AUROC for NN was 0.676 (95% 0.666-0.687), compared with 0.633 (95% CI 0.620-0.647) for LR. For bile leak, AUROC for NN was 0.750 (95% CI 0.739-0.761), compared with 0.722 (95% CI 0.698-0.746) for LR. For pancreatic fistula, AUROC for NN was 0.746 (95% CI 0.733-0.760), compared with 0.713 (95% CI 0.703-0.723) for LR. Variables related to intra-operative information, such as surgical approach, biliary reconstruction, and pancreatic gland texture were highly important for model predictions.

DISCUSSION

Machine learning showed a marginal advantage over traditional statistical techniques in predicting procedure-specific outcomes. However, models that included intra-operative information performed better than those that did not, suggesting that NSQIP procedure-targeted datasets may be strengthened by including relevant intra-operative information.

Colorectal resection in end-stage renal disease (ESRD) patients: experience from a single tertiary center

BACKGROUND

End-stage renal disease (ESRD) and renal replacement therapy (RRT) are important risk factors for post-operative morbidity and mortality but remains poorly reported in colorectal surgery. This study aims to evaluate postoperative outcomes of ESRD patients under RRT undergoing colorectal resection.

METHODS

All ESRD patients under RRT who underwent colorectal resection between 2006 and 2019 were retrospectively reviewed. Perioperative outcomes were analysed, such as risk factors of postoperative complications.

RESULTS

Forty-two patients were analysed, including 27 emergency and 15 elective surgeries. The most frequent indication was acute colonic ischemia for emergency and malignancy for elective procedures. Laparoscopic approach was used in 12 patients (29%), without difference between elective and emergency groups. Postoperative severe complications rate (including deaths) was 50% (21/42), including 56% (15/27) and 40% (6/15) in emergency and elective groups, respectively (p = .334). Anastomotic leak was observed in 3 of the 23 patients (13%) undergoing digestive anastomosis, (1 in emergency and 2 in elective groups, p = .246). The postoperative mortality rate was 29%, not significantly different between groups. The median hospital stay was 14.5 days (8-42). At univariate analysis, history of cardiac event (p = .028) and open approach (p = .040) were associated with severe complications, and ASA score >3 (p = .043), history of cardiac event (p = .001) and diabetes (p = .030) associated with mortality.

CONCLUSIONS

Colorectal surgery in ESRD patient exposes to high risk of morbidity and mortality, even in the elective setting, especially in patients with comorbidities like cardiac event and diabetes. Careful patient selection and closed management is required in such fragile patients.

Bowel Dysfunction after Low Anterior Resection for Colorectal Cancer: A Frequent Late Effect of Surgery Infrequently Treated

BACKGROUND

The development of major low anterior resection syndrome (LARS) after low anterior resection is severely detrimental to quality of life, yet awareness of it by clinicians and patients and the frequency of treatment of LARS is unclear.

STUDY DESIGN

Patients who underwent low anterior resection for sigmoid or rectal cancer at a tertiary center between 2007 and 2017 (n = 798) were surveyed in 2019 to assess LARS symptoms and report medications or treatment received for LARS. LARS scores were calculated (score range 0-42) and normalized to published data on LARS prevalence in the general population in Europe, stratified by age (<50 or ≥50) and sex.

RESULTS

Of the 594 patients (74%) who returned the survey, 255 (43%) were identified as having major LARS (LARS score ≥30). This prevalence was significantly higher than published normative data from Denmark and Amsterdam when stratified by age greater than or less than 50 and sex. Patients with major LARS infrequently reported current use of first-line therapies (antidiarrheal medications 32%, fiber supplements 16%, and both 13%). Only 3% reported receiving second-line therapy of transanal irrigations and/or pelvic floor rehabilitation, and only 1% had undergone third-line therapy of sacral nerve stimulator implantation.

CONCLUSION

Major LARS is common yet seemingly underrecognized by clinicians because less than half of patients are on first-line therapy and practically none are on second- and third-line therapies. Long-term follow-up of patients after low anterior resection, improved preoperative and postoperative education, and continued symptom assessment is necessary to improve treatment of major LARS.

Defining Anastomotic Leak and the Clinical Relevance of Leaks

Surgeons universally dread gastrointestinal anastomotic leaks, yet the precise definition is not widely agreed on despite international consensus guidelines. Likewise, leaks are not uniformly reported which makes comparisons across studies flawed. Leak rates range from 1 to 3% for ileocolonic, 0.5 to 18% for colorectal, and 5 to 19% for coloanal anastomoses. The sequelae of an anastomotic leak vary but generally correlate with the need for a change in clinical management, from minimal changes to the need for reoperation. Short- and long-term outcomes can be life-altering or life-threatening. Temporary or permanent stomas may be necessary and low pelvic anastomotic leaks may affect bowel function. For cancer patients, leaks can delay treatment and negatively affect oncologic outcomes. In Crohn's patients, leaks are associated with higher recurrence rates. In essence, the lack of agreement on the definition of an anastomotic leak inhibits meaningful understand of its epidemiology, prevention, and treatment.

Anastomotic leak in patients with acute complicated diverticulitis undergoing primary anastomosis: risk factors and the role of diverting loop ileostomy

BACKGROUND

Recent data has suggested that primary anastomosis (PA), with or without a diverting loop ileostomy (DLI), is a safe option for the treatment of acute complicated diverticulitis. This study aimed to evaluate risk factors associated with anastomotic leak in patients who underwent a sigmoid colectomy with PA and to determine whether a DLI was protective against a clinically significant anastomotic leak.

METHODS

Patients with acute complicated diverticulitis who underwent a laparoscopic or open sigmoid colectomy with PA, with or without a DLI, were identified in the NSQIP PUF(2016-2017). The rates of anastomotic leak, receipt of DLI, and type of leak management were compared. Multivariate logistic regression was performed.

RESULTS

There were 497 patients identified. Seventy-nine(15.9%) patients had a DLI, while 418 (84.1%) did not. Twenty-six anastomotic leaks were identified (5.2%). On multivariate analysis, current smoking (OR 4.02; 95% CI 1.44-11.26) and chronic steroid use (OR 3.84; 95% CI 1.16-12.69) were significantly associated with an increased risk of leak. Of the 26 patients with anastomotic leaks, 5 (19.2%) had a DLI. There was no significant difference in the rate of leak between those with a DLI(5; 6.3%) and those without(21; 5.3%; p = 0.59). Patients who had a DLI were significantly less likely to experience an anastomotic leak requiring re-operation (p < 0.01).

CONCLUSIONS

Regardless of the presence of a DLI, chronic steroid use and smoking are associated with an increased risk of anastomotic leak in patients with acute complicated diverticulitis undergoing colectomy with PA. The presence of a diverting loop ileostomy is protective against re-operation.