Radiological evaluation of colorectal anastomoses

CT scan for early diagnosis of anastomotic leak after colorectal surgery: is rectal contrast useful?

BACKGROUND

Computed tomography (CT) scan with rectal contrast enema (RCE-CT) could increase the detection rate of anastomotic leaks (AL) in the early postoperative period following colorectal surgery, compared to CT scan without RCE. The aim of this study was to assess the benefit of RCE-CT for the early diagnosis of AL following colorectal surgery.

METHODS

Patients who had a RCE-CT for suspected AL in the early postoperative period following colorectal surgery with anastomosis between January 2012 and July 2019 at the Dijon University Hospital were retrospectively included. All images were reviewed by two independent observers who were blinded to the original report. The reviewers reported for each patient whether an AL was present or not in each imaging modality (CT scan, then RCE-CT). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were then calculated to determine the diagnostic performance of each modality.

RESULTS

One hundred and thirty-nine patients were included. RCE-CT had an increased NPV compared to CT scan (82% vs 77% (p = 0.02) and 84% vs 68% (p < 0.0001) for observers 1 and 2, respectively). RCE-CT had an increased sensitivity compared to CT scan (79% vs 48% (p < 0.0001) for observer 2). RCE-CT had a significant lower false-negative rate for both observers: 18% vs 23% (p = 0.02) and 16% vs 32% (p < 0.0001).

CONCLUSIONS

RCE-CT improved the detection rates of AL in the early period following colorectal surgery. RCE-CT should be recommended when a CT scan is negative and AL is still suspected.

Post-Surgical Imaging Assessment in Rectal Cancer: Normal Findings and Complications

Rectal cancer (RC) is one of the deadliest malignancies worldwide. Surgery is the most common treatment for RC, performed in 63.2% of patients. The type of surgical approach chosen aims to achieve maximum residual function with the lowest risk of recurrence. The selection is made by a multidisciplinary team that assesses the characteristics of the patient and the tumor. Total mesorectal excision (TME), including both low anterior resection (LAR) and abdominoperineal resection (APR), is still the standard of care for RC. Radical surgery is burdened by a 31% rate of major complications (Clavien-Dindo grade 3-4), such as anastomotic leaks and a risk of a permanent stoma. In recent years, less-invasive techniques, such as local excision, have been tested. These additional procedures could mitigate the morbidity of rectal resection, while providing acceptable oncologic results. The "watch and wait" approach is not a globally accepted model of care but encouraging results on selected groups of patients make it a promising strategy. In this plethora of treatments, the radiologist is called upon to distinguish a physiological from a pathological postoperative finding. The aim of this narrative review is to identify the main post-surgical complications and the most effective imaging techniques.

Usefulness of CT scan as part of an institutional protocol for proactive leakage management after low anterior resection for rectal cancer

PURPOSE

Highly selective fecal diversion after low anterior resection (LAR) for rectal cancer requires a strict postoperative protocol for early detection of anastomotic leakage (AL). The purpose of this study was to evaluate C-reactive protein (CRP)-based CT imaging in diagnosis and subsequent management of AL.

METHODS

All patients that underwent a CT scan for suspicion of AL after transanal total mesorectal excision for rectal cancer in a university center (2015-2020) were included. Outcome parameters were diagnostic yield of CT and timing of CT and subsequent intervention.

RESULTS

Forty-four out of 125 patients underwent CT (35%) with an overall median interval of 5 h (IQR 3-6) from CRP measurement. The anastomosis was diverted in 7/44 (16%). CT was conclusive or highly suspicious for AL in 23, with confirmed AL in all those patients (yield 52%), and was false-negative in one patient (sensitivity 96%). CT initiated subsequent intervention after median 6 h (IQR 3-25). There was no or minor suspicion of AL on imaging in all 20 patients without definitive diagnosis of AL. After CT imaging on day 2, AL was confirmed in 0/1, and these proportions were 6/6 for day 3, 7/10 for day 4, 2/4 for day 5, and 9/23 beyond day 5.

CONCLUSION

In the setting of an institutional policy of highly selective fecal diversion and pro-active leakage management, the yield of selective CT imaging using predefined CRP cut-off values was 52% with a sensitivity of 96%, enabling timely and tailored intervention after a median of 6 h from imaging.

Contrast-enhanced abdominal computed tomography to evaluate anastomotic integrity before ileostomy closure in postoperative colorectal cancer patients

PURPOSE

To investigate the usefulness of contrast-enhanced abdominal computed tomography (CECT) to predict clinically significant anastomotic leakage (CSAL) in patients who received colorectal cancer surgery with diverting ileostomy.

METHODS

In this retrospective cohort study, patients who underwent colorectal cancer surgery with diverting ileostomy from January 2014 to May 2018 and postoperative CECT were included. The performance of significant CECT features, identified using multivariable logistic regression, to predict CSAL was calculated. In subgroup analysis, the areas under the receiver operating characteristic curve (AUROCs) were compared between CECT and water-soluble contrast enema (WSCE) using DeLong's method.

RESULTS

Of 325 patients (median age, 58 years; 213 men), CECT was routinely performed to evaluate cancer status in 307 (94.5%), and CSAL was observed in 28 (8.6%). After multivariable adjustment, anastomotic mural defect (odds ratio [OR] 5.24; 95% confidence interval [CI] 1.77-15.51; p = 0.003), perianastomotic air (OR 7.28; 95% CI 1.82-29.17; p = 0.007) and ischemic colitis (OR 3.30; 95% CI 1.13-9.61; p = 0.029) were significantly associated with CSAL. The sensitivity, specificity, accuracy, and positive and negative predictive values of significant CECT features were 60.7%, 88.2%, 85.9%, 32.7%, and 96.0%, respectively. In subgroup analysis of 144 patients, the AUROC using significant CECT features (optimal sensitivity/specificity, 50.0%/90.4%) was comparable to that using WSCE (optimal sensitivity/specificity, 12.5%/97.8%) to predict CSAL (0.704 vs. 0.552, p = 0.085).

CONCLUSION

CECT performed after colorectal cancer surgery may be useful to assess anastomotic integrity before ileostomy closure, especially to negatively predict CSAL. In the presence of anastomotic mural defect, perianastomotic air, or ischemic colitis, WSCE may be recommended to exclude CSAL.

The importance of rectal contrast in CT assessment to detect anastomotic leakage after colorectal surgery

AIM

Computed tomography (CT) is currently the diagnostic tool most often used to detect anastomotic leakage (AL) after colorectal surgery. The aim of this study was to investigate the value of rectal contrast.

METHOD

All patients who underwent colorectal surgery with a primary anastomosis between 2009 and 2018 were identified from a prospectively maintained database. Patients who underwent postoperative CT scanning in suspicion of AL were included. The clinical and radiological outcomes of patients with and without rectal contrast were compared.

RESULTS

A total of 1183 patient records were reviewed; 225 patients underwent CT-abdomen in suspicion of AL. Of these patients, 175 (77.8%) received rectal contrast. Sensitivity and specificity in this group were 78% and 94%, respectively. The positive predictive value (PPV) was 0.78 and the negative predictive value (NPV) was 0.94. In the group without rectal contrast (n = 50), sensitivity was 47%, specificity 88%, PPV 0.66 and NPV 0.76. In patients who received rectal contrast, contrast reached the anastomosis in 81.7% compared with 26.0% in patients who were given only oral contrast (p < 0.001). The sensitivity increased to 93% in the group of patients with contrast at the anastomosis, the specificity to 97%, the PPV to 0.88 and the NPV to 0.98. No adverse events were observed after the use of rectal contrast.

CONCLUSION

The use of rectal contrast led to a significant increase in the predictive value of CT scanning for AL, especially when it reached the anastomosis. This suggests that rectal contrast is a safe and useful adjunct to CT-abdomen in the detection of AL.

Postoperative complications of colorectal cancer

Colorectal cancer is the third most common cancer, and surgery is the most common treatment. Several surgical options are available, but each is associated with a range of potential complications. The timely and efficient identification of these complications is vital for effective clinical management of these patients in order to minimise their morbidity and mortality. This review aims to describe the range of commonly performed surgical treatments for colorectal surgery. In addition, frequent post-surgical complications are explored with investigative options explained and illustrated.

Evaluation of Pelvic Anastomosis by Endoscopic and Contrast Studies Prior to Ileostomy Closure: Are Both Necessary? A Single Institution Review

Contrast enema is the gold standard technique for evaluating a pelvic anastomosis (PA) prior to ileostomy closure. With the increasing use of flexible endoscopic modalities, the need for contrast studies may be unnecessary. The objective of this study is to compare flexible endoscopy and contrast studies for anastomotic inspection prior to defunctioning stoma reversal. Patients with a protected PA undergoing ileostomy closure between July 2014 and June 2019 at our institution were retrospectively identified. Demographics and clinical outcomes in patients undergoing preoperative evaluation with endoscopic and/or contrast studies were analyzed. We identified 207 patients undergoing ileostomy closure. According to surgeon's preference, 91 patients underwent only flexible endoscopy (FE) and 100 patients underwent both endoscopic and contrast evaluation (FE + CE) prior to reversal. There was no significant difference in pelvic anastomotic leak (2.2% vs. 1%), anastomotic stricture (1.1% vs. 6%), pelvic abscess (2.2% vs. 3.0%), or postoperative anastomotic complications (4.4% vs. 9%) between groups FE and FE + CE (P > .05). Flexible endoscopy alone appears to be an acceptable technique for anastomotic evaluation prior to ileostomy closure. Further studies are needed to determine the effectiveness of different diagnostic modalities for pelvic anastomotic inspection.

Evaluation of the inflammatory markers CCL8, CXCL5, and LIF in patients with anastomotic leakage after colorectal cancer surgery

PURPOSE

Anastomotic leakage constitutes a dreaded complication after colorectal surgery, leading to increased morbidity and mortality as well as prolonged hospitalization. Most leakages become clinically apparent about 8 days after surgery; however, early detection is quintessential to reduce complications and to improve patients' outcome. We therefore investigated the significance of specific protein expression profiles as putative biomarkers, indicating anastomotic leakage.

METHODS

In this single-center prospective cohort study serum and peritoneal fluid samples-from routinely intraoperatively inserted drainages-of colorectal cancer patients were collected 3 days after colorectal resection. Twenty patients without anastomotic leakage and 18 patients with an anastomotic leakage and without other complications were included. Protein expression of seven inflammatory markers in serum and peritoneal fluid was assessed by multiplex ELISA and correlated with patients' clinical data.

RESULTS

Monocyte chemoattractant protein 2 (CCL8/MCP-2), leukemia-inhibiting factor (LIF), and epithelial-derived neutrophil-activating protein (CXCL5/ENA-78) were significantly elevated in peritoneal fluid but not in serum samples from patients subsequently developing anastomotic leakage after colorectal surgery. No expressional differences could be found between grade B and grade C anastomotic leakages.

CONCLUSION

Measurement 3 days after surgery revealed altered protein expression patterns of the inflammatory markers CCL8/MCP2, LIF, and CXCL5/ENA-78 in peritoneal fluid from patients developing anastomotic leakage after colorectal surgery. Further studies with a larger patient cohort with inclusion of different variables are needed to evaluate their potential as predictive biomarkers for anastomotic leakage.

Detection of early anastomotic leakage by intraperitoneal microdialysis after low anterior resection for rectal cancer: a prospective cohort study

AIM

Anastomotic leakage (AL) is a common and serious complication following sphincter-preserving surgery for rectal cancer. Early detection and intervention can improve clinical outcomes. The aim of this prospective cohort study was to compare intraperitoneal microdialysis with a clinical scoring system for early detection of AL.

METHOD

A microdialysis catheter was anchored near the anastomosis at low anterior resection (LAR) for rectal cancer. Peritoneal fluid samples were analysed (lactate, pyruvate, glucose and glycerol concentration) 4-hourly and compared with a daily clinical leak score (DULK = Dutch leakage). At day 7 a pelvic CT with rectal contrast enema was performed to establish if there had been a radiological leak.

RESULTS

In this two-centre study, 129 patients [median age 65 (26-82) years; 60.5% male] underwent LAR. The leak rate was 27% (grade A, n = 11; grade B, n = 12; grade C, n = 12). Receiver operator characteristic analysis demonstrated a lactate cut-off value of 9.8 mm and had 77% sensitivity, 82% specificity, 78% accuracy, a positive predictive value (PPV) of 58, a negative predictive value (NPV) of 88 (CI 79-94) and an area under the curve (AUC) of 0.9 for AL. This compared with a clinical score ≥ 4, which had 57% sensitivity, 79% specificity, 71% accuracy, a PPV of 46, a NPV of 82 and an AUC of 0.7 for AL. The mean day for a positive test when using delta lactate ≥ 6.3 mm was 1.6 days and for leak score ≥ 4 it was 3.3 days (NS).

CONCLUSION

When AL occurs, intraperitoneal lactate concentration increases over time, and at a certain cut-off has a higher sensitivity, specificity, accuracy, PPV and NPV than a clinical scoring system.

Urgent Multidetector Computed Tomography in Colon Cancer: Postsurgical Changes and Early Complications

Complications after surgery for colorectal cancer are common in emergency departments. Multidetector computed tomography plays a fundamental role in the follow-up of patients after surgery, because it enables the detection of relapse and complications. Radiologists need to be familiar with different surgical techniques and the normal postsurgical changes so that we can differentiate them from potential complications and relapse. This article reviews the multidetector computed tomography findings that can be considered normal after surgical intervention for colorectal cancer as well as the most common early complications seen in postsurgical colorectal cancer patients presenting at emergency departments.

Hybrid 18F-FDG PET/CT of colonic anastomosis

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a known method to diagnose inflammatory processes and thus may be a promising imaging technique to detect anastomotic bowel leak. The aim of this study was to assess postoperative FDG uptake in colorectal anastomosis in patients without suspicion of active infection or anastomotic leakage. Patients, methods: Design of a prospective observational pilot study in order to assess normal FDG uptake in the patient anastomosis after colorectal surgery. Patients that underwent colorectal surgery with primary anastomosis received FDG-PET of the abdomen, 2–6 days postoperatively. Results: 35 patients met the inclusion criteria. Three patients were not scanned for various reasons. Of the remaining 32 patients, one demonstrated an increased uptake of FDG at the site of the anastomosis. In the other 31 patients FDG uptake was negligible (n = 17) or scored as physiological (n = 14). None of the scanned patients developed a clinical relevant anastomotic leakage within the first 30 days after surgery. Conclusion: The present study shows that FDG uptake in colorectal anastomosis remains low within the first six days after surgery in patients without anastomotic leakage. Therefore, FDG-PET might be useful to investigate further as a tool to detect anastomotic leakage in an the early postoperative phase.

Definition of colorectal anastomotic leakage: A consensus survey among Dutch and Chinese colorectal surgeons

AIM

To determine the level of consensus on the definition of colorectal anastomotic leakage (CAL) among Dutch and Chinese colorectal surgeons.

METHODS

Dutch and Chinese colorectal surgeons were asked to partake in an online questionnaire. Consensus in the online questionnaire was defined as > 80% agreement between respondents on various statements regarding a general definition of CAL, and regarding clinical and radiological diagnosis of the complication.

RESULTS

Fifty-nine Dutch and 202 Chinese dedicated colorectal surgeons participated in the online survey. Consensus was found on only one of the proposed elements of a general definition of CAL in both countries: ‘extravasation of contrast medium after rectal enema on a CT scan’. Another two were found relevant according to Dutch surgeons: ‘necrosis of the anastomosis found during reoperation’, and ‘a radiological collection treated with percutaneous drainage’. No consensus was found for all other proposed elements that may be included in a general definition.

CONCLUSION

There is no universally accepted definition of CAL in the Netherlands and China. Diagnosis of CAL based on clinical manifestations remains a point of discussion in both countries. Dutch surgeons are more likely to report ‘subclinical’ leaks as CAL, which partly explains the higher reported Dutch CAL rates.

Integrated approach to colorectal anastomotic leakage: Communication, infection and healing disturbances

Colorectal anastomotic leakage (CAL) remains a major complication after colorectal surgery. Despite all efforts during the last decades, the incidence of CAL has not decreased. In this review, we summarize the available strategies regarding prevention, prediction and intervention of CAL and categorize them into three categories: communication, infection and healing disturbances. These three major factors actively interact during the onset of CAL. We aim to provide an integrated approach to CAL based on its etiology. The intraoperative air leak test, intraoperative endoscopy, radiological examinations and stoma construction mainly aim to detect and to prevent communication between the intra- and extra-luminal content. Other strategies including postoperative drainage, antibiotics, and infectious-parameter evaluation are intended to detect and prevent anastomotic or peritoneal infection. Most currently available interventions for CAL focus on the control of communication and infection, while strategies targeting the healing disturbances such as lifestyle changes, oxygen therapy and evaluation of metabolic biomarkers still lack wide clinical application. This simplified categorization may contribute to an integrated understanding of CAL. We strongly believe that this integrated approach should be taken into consideration during clinical practice. An integrated approach to CAL could contribute to a better understanding of the etiology of CAL and eventually better patient outcome.

Cloacal Prolapse in Raptors: Review of 16 Cases

Sixteen cases of cloacal prolapse in raptors were reviewed in this study. Colonic prolapse was the most common presentation (56% of cases). Red-tailed hawks ( Buteo jamaicensis ) were overrepresented, comprising 66% of colonic prolapse cases. In cases of colonic prolapse, postsurgical stricture formation was a commonly identified complication after resection and anastomosis of the colon. A novel technique was used in 2 cases of colonic prolapse, in which sterile, semirigid rubber tubing was placed in the distal colon and removed per-cloaca at the end of the procedure; this facilitated a secure, fluid-tight anastomosis while maintaining sufficient intestinal lumen. Oviductal prolapse (31% of cases) was associated with the most guarded prognosis (40% treatment success). Cloacoliths were treated successfully in 2 birds (13% of cases) by minimally invasive per-cloacal manual removal.

Predictive Factors for Anastomotic Leakage After Colorectal Surgery: Study Protocol for a Prospective Observational Study (REVEAL Study)

Background

Anastomotic leakage (AL) remains the most important complication following colorectal surgery, and is associated with high morbidity and mortality rates. Previous research has focused on identifying risk factors and potential biomarkers for AL, but the sensitivity of these tests remains poor.

Objective

This prospective multicenter observational study aims at combining multiple parameters to establish a diagnostic algorithm for colorectal AL.

Methods

This study aims to include 588 patients undergoing surgery for colorectal carcinoma. Patients will be eligible for inclusion when surgery includes the construction of a colorectal anastomosis. Patient characteristics will be collected upon consented inclusion, and buccal swabs, breath, stool, and blood samples will be obtained prior to surgery. These samples will allow for the collection of information regarding patients’ inflammatory status, genetic predisposition, and intestinal microbiota. Additionally, breath and blood samples will be taken postoperatively and patients will be strictly observed during their in-hospital stay, and the period shortly thereafter.

Results

This study has been open for inclusion since August 2015.

Conclusions

An estimated 8-10% of patients will develop AL following surgery, and they will be compared to non-leakage patients. The objectives of this study are twofold. The primary aim is to establish and validate a diagnostic algorithm for the pre-operative prediction of the risk of AL development using a combination of inflammatory, immune-related, and genetic parameters. Previously established risk factors and novel parameters will be incorporated into this algorithm, which will aid in the recognition of patients who are at risk for AL. Based on these results, recommendations can be made regarding the construction of an anastomosis or deviating stoma, and possible preventive strategies. Furthermore, we aim to develop a new algorithm for the post-operative diagnosis of AL at an earlier stage, which will positively reflect on short-term survival rates.

Trial Registration

Clinicaltrials.gov: NCT02347735; https://clinicaltrials.gov/ct2/show/NCT02347735 (archived by WebCite at http://www.webcitation.org/6hm6rxCsA)

Contrast medium at the site of the anastomosis is crucial in detecting anastomotic leakage with CT imaging after colorectal surgery

PURPOSE

The use of computed tomography (CT) to detect anastomotic leakage (AL) is becoming the standard of care. Accurate detection of AL is crucial. The aim of this study was to define CT criteria that are most predictive for AL.

METHODS

From January 2006 to December 2012, all consecutive patients who had undergone CT imaging because of clinical suspicion of anastomotic leakage after colorectal surgery were analysed. All CT scans were re-evaluated by two independent abdominal radiologists blinded for clinical outcome. The images were scored with a set of criteria and a conclusion whether or not AL was present was drawn. Each separate criterion was analysed for its value in predicting AL by uni- and multivariable logistic regression

RESULTS

Of 668 patients with colorectal surgery, 108 had undergone CT imaging within 16 days postoperatively. According to our standard of reference, 34 (31%) of the patients had AL. Univariable analysis showed that "fluid near anastomosis" (radiologist 1 (rad 1), p < 0.001; radiologist 2 (rad 2), p < 0.001) and "air near anastomosis" (rad 1, p < 0.001; rad 2, p < 0.001), "air intra-abdominally" (rad 1, p = 0.019; rad 2, p = 0.004) and "contrast leakage" (rad 1, p < 0.001; rad 2, p < 0.001) were associated with AL. Contrast leakage was the only independent predictor for AL in multivariable analysis for both radiologists (rad 1, OR 5.43 (95% CI 1.18-25.02); rad 2, OR 8.51 (95% CI 2.21-32.83)).

CONCLUSION

The only independent variable predicting AL is leakage of contrast medium. To improve the accuracy of CT imaging, optimal contrast administration near the anastomosis appears to be crucial.

Anastomotic leakage after colorectal surgery: diagnostic accuracy of CT

OBJECTIVES

To evaluate the diagnostic accuracy of CT in postoperative colorectal anastomotic leakage (AL).

METHODS

Two independent blinded radiologists reviewed 153 CTs performed for suspected AL within 60 days after surgery in 131 consecutive patients, with (n = 58) or without (n = 95) retrograde contrast enema (RCE). Results were compared to original interpretations. The reference standard was reoperation or consensus (a radiologist and a surgeon) regarding clinical, laboratory, radiological, and follow-up data after medical treatment.

RESULTS

AL was confirmed in 34/131 patients. For the two reviewers and original interpretation, sensitivity of CT was 82 %, 87 %, and 71 %, respectively; specificity was 84 %, 84 %, and 92 %. RCE significantly increased the positive predictive value (from 40 % to 88 %, P = 0.0009; 41 % to 92 %, P = 0.0016; and 40 % to 100 %, P = 0.0006). Contrast extravasation was the most sensitive (reviewers, 83 % and 83 %) and specific (97 % and 97 %) sign and was significantly associated with AL by univariate analysis (P < 0.0001 and P < 0.0001). By multivariate analysis with recursive partitioning, CT with RCE was accurate to confirm or rule out AL with contrast extravasation.

CONCLUSIONS

CT with RCE is accurate for diagnosing postoperative colorectal AL. Contrast extravasation is the most reliable sign. RCE should be performed during CT for suspected AL.

KEY POINTS

• CT accurately diagnosed clinically suspected colorectal AL and showed good interobserver agreement • Contrast extravasation was the most sensitive and specific CT sign • Retrograde contrast enema during CT improved positive predictive value • Retrograde contrast enema decreased false-negative or indeterminate original CT interpretations.

Systematic review of preoperative, intraoperative and postoperative risk factors for colorectal anastomotic leaks

BACKGROUND

Anastomotic leak (AL) represents a dreaded complication following colorectal surgery, with a prevalence of 1-19 per cent. There remains a lack of consensus regarding factors that may predispose to AL and the relative risks associated with them. The objective was to perform a systematic review of the literature, focusing on the role of preoperative, intraoperative and postoperative factors in the development of colorectal ALs.

METHODS

A systematic review was performed to identify adjustable and non-adjustable preoperative, intraoperative and postoperative factors in the pathogenesis of AL. Additionally, a severity grading system was proposed to guide treatment.

RESULTS

Of 1707 papers screened, 451 fulfilled the criteria for inclusion in the review. Significant preoperative risk factors were: male sex, American Society of Anesthesiologists fitness grade above II, renal disease, co-morbidity and history of radiotherapy. Tumour-related factors were: distal site, size larger than 3 cm, advanced stage, emergency surgery and metastatic disease. Adjustable risk factors were: smoking, obesity, poor nutrition, alcohol excess, immunosuppressants and bevacizumab. Intraoperative risk factors were: blood loss/transfusion and duration of surgery more than 4 h. Stomas lessen the consequences but not the prevalence of AL. In the postoperative period, CT is the most commonly used imaging tool, with or without rectal contrast, and a C-reactive protein level exceeding 150 mg/l on day 3-5 is the most sensitive biochemical marker. A five-level classification system for AL severity and appropriate management is presented.

CONCLUSION

Specific risk factors and their potential correction or indications for stoma were identified. An AL severity score is proposed to aid clinical decision-making.

CT scan-based modelling of anastomotic leak risk after colorectal surgery

AIM

Prolonged ileus, low-grade fever and abdominal discomfort are common during the first week after colonic resection. Undiagnosed anastomotic leak carries a poor outcome and computed tomography (CT) scan is the best imaging tool for assessing postoperative abdominal complications. We used a CT scan-based model to quantify the risk of anastomotic leak after colorectal surgery.

METHOD

A case-control analysis of 74 patients who underwent clinico-radiological evaluation after colorectal surgery for suspicion of anastomotic leak was undertaken and a multivariable analysis of risk factors for leak was performed. A logistic regression model was used to identify determinant variables and construct a predictive score.

RESULTS

Out of 74 patients with a clinical suspicion of anastomotic leak, 17 (23%) had this complication confirmed following repeat laparotomy. In multivariate analysis, three variables were associated with anastomotic leak: (1) white blood cells count > 9 × 10(9) /l (OR = 14.8); (2) presence of ≥ 500 cm(3) of intra- abdominal fluid (OR = 13.4); and (3) pneumoperitoneum at the site of anastomosis (OR = 9.9). Each of these three parameters contributed one point to the risk score. The observed risk of leak was 0, 6, 31 and 100%, respectively, for patients with scores of 0, 1, 2 and 3. The area under the receiver operating characteristic curve for the score was 0.83 (0.72-0.94).

CONCLUSION

This CT scan-based model seems clinically promising for objective quantification of the risk of a leak after colorectal surgery.

Beware of false-negative CT scan for anastomotic leakage after colonic surgery

BACKGROUND

Anastomotic leakage is one of the most life-threatening complications after colonic surgery. Correct diagnosis and treatment is important to reduce morbidity and mortality. An abdominal CT scan is one of the main diagnostic tools in diagnosing anastomotic leaks. The aim of this study was to examine the accuracy of abdominal CT scanning to detect anastomotic leakage and to evaluate the consequences of a false-negative CT outcome.

METHODS

All consecutive patients who underwent colonic resection for malignant disease between 2009 and 2011 or for benign disease in 2010 were reviewed. Patients in whom a postoperative abdominal CT scan was performed to detect anastomotic leakage were included.

RESULTS

In 97 of 524 patients who underwent colonic surgery, an abdominal CT scan was performed for the suspicion of anastomotic leakage. Overall leakage rate was 10.9 % (n = 57). Mortality rate after leakage was 21.1 % (n = 12). Results from all abdominal CT scans revealed an overall sensitivity of 0.59 (95 % CI 0.43-0.73), a specificity of 0.88 (95 % CI 0.75-0.95), positive predictive value 0.82 (95 % CI 0.64-0.92), negative predictive value 0.70 (95 % CI 0.57-0.81), and an accuracy of 74 %. Delayed reintervention for anastomotic leakage due to a false-negative CT outcome resulted in death in 62.5 % (n = 5).

CONCLUSION

The sensitivity of abdominal CT scanning after colonic surgery is relatively low. A negative CT scan does not rule out anastomotic leakage. Even with a negative CT scan, we should remain equally alert at clinical deterioration as an argument for timely intervention.

Prediction and diagnosis of colorectal anastomotic leakage: A systematic review of literature

Although many studies have focused on the preoperative risk factors of anastomotic leakage after colorectal surgery (CAL), postoperative delay in diagnosis is common and harmful. This review provides a systematic overview of all available literature on diagnostic tools used for CAL. A systematic search of literature was undertaken using Medline, Embase, Cochrane and Web-of-Science libraries. Articles were selected when a diagnostic or prediction tool for CAL was described and tested. Two reviewers separately assessed the eligibility and level of evidence of the papers. Sixty-nine articles were selected (clinical methods: 11, laboratory tests: 12, drain fluid analysis: 12, intraoperative techniques: 22, radiology: 16). Clinical scoring leads to early awareness of probability of CAL and reduces delay of diagnosis. C-reactive protein measurement at postoperative day 3-4 is helpful. CAL patients are characterized by elevated cytokine levels in drain fluid in the very early postoperative phase in CAL patients. Intraoperative testing using the air leak test allows intraoperative repair of the anastomosis. Routine contrast enema is not recommended. If CAL is clinically suspected, rectal contrast-computer tomography is recommended by a few studies. In many studies a “no-test” control group was lacking, furthermore no golden standard for CAL is available. These two factors contributed to a relatively low level of evidence in the majority of the papers. This paper provides a systematic overview of literature on the available tools for diagnosing CAL. The study shows that colorectal surgery patients could benefit from some diagnostic interventions that can easily be performed in daily postoperative care.

Polymerase chain reaction for Enterococcus faecalis in drain fluid: the first screening test for symptomatic colorectal anastomotic leakage. The Appeal-study: analysis of parameters predictive for evident anastomotic leakage

PURPOSE

With current diagnostic methods, the majority of patients with symptomatic colorectal anastomotic leakage(CAL) is identified approximately 1 week after operation.The aim of this study is to determine whether real-time polymerase chain reaction (RT-PCR) for detection of Escherichia coli and Enterococcus faecalis on drain fluid can serve as a screening test for CAL in the early postoperative phase.

METHODS

All patients included in this multicenter prospective observational study underwent left-sided colorectal resection for both malignant and benign diseases with construction of an anastomosis. In all patients, an intra-abdominal drain was placed during operation. During the first five postoperative days, drain fluid was processed for RT-PCR. The quantitative results of the RT-PCR on days 2 to 5 were compared to the results of day 1 in order to detect concentration changes.

RESULTS

In total, 243 patients, with both benign and malignant diseases, were included of whom 19 (7.8 %) developed symptomatic CAL. An increase in E. coli concentration was found insignificantly more patients with CAL on day 4 and 5 [p =0.0004; diagnostic odds ratio (DOR) 7.9]. For E. faecalis, this result was found for days 2, 3, and 4 (p <0.003) with highest DOR on day 3 (31.6). Sensitivity and negative predictive values were 92.9 and 98.7 %, respectively, virtually ruling out CAL in case of negative test results on the third postoperative day.

CONCLUSION

Quantitative PCR for E. faecalis performed on drain fluid may be an objective, affordable and fast screening tool for symptomatic colorectal anastomotic leakage.

Late anastomotic leakage in colorectal surgery: a significant problem

AIM

Reported incidence rates of colorectal anastomotic leakage (AL) vary between 2.5 and 20%. There is little information on late anastomotic leakage (LAL). The aim of this study was to determine the incidence of LAL after colorectal resection.

METHOD

All patients undergoing colorectal resection with primary anastomosis between January 2004 and October 2009 at the University Medical Center Groningen were included. LAL was defined as anastomotic leakage diagnosed more than 30 days after surgery.

RESULTS

One hundred and forty-one patients were analysed. Indications for surgery included both benign and malignant conditions. The incidence of early anastomotic leakage (EAL) within 30 days after surgery was 13%. The LAL rate was 6%. Eighty-nine per cent of patients with EAL underwent relaparotomy compared with 44% for LAL (P = 0.02).

CONCLUSION

One-third of all anastomotic leakages were diagnosed more than 30 days after surgery. Of these, 44% underwent relaparotomy. Patients with leakage diagnosed within 30 days after surgery were more likely to undergo relaparotomy. LAL is a significant problem after colorectal surgery.

Colorectal anastomotic leakage: Aspects of prevention, detection and treatment

All colorectal surgeons are faced from time to time with anastomotic leakage after colorectal surgery. This complication has been studied extensively without a significant reduction of incidence over the last 30 years. New techniques of prevention, by innovative anastomotic techniques should improve results in the future, but standardization and “teachability” should be guaranteed. Risk scoring enables intra-operative decision-making whether to restore continuity or deviate. Early detection can lead to reduction in delay of diagnosis as long as a standard system is used. For treatment options, no firm evidence is available, but future studies could focus on repair and saving of the anastomosis on the one hand or anastomotical breakdown and definitive colostomy on the other hand.

Systematic review on the value of CT scanning in the diagnosis of anastomotic leakage after colorectal surgery

BACKGROUND

Timely diagnosis of anastomotic leakage after colorectal surgery and adequate treatment is important to reduce morbidity and mortality. Abdominal computed tomography (CT) scanning is the diagnostic tool of preference, but its value may be questionable in the early postoperative period. The accuracy of CT scanning for the detection of anastomotic leakage and its role in timing of intervention was evaluated.

METHODS

A systematic literature search was performed. Relevant publications were identified from four electronic databases between 1990 and 2011. Inclusion criteria were human studies, studies published in English or Dutch, colorectal surgery with primary anastomosis, and abdominal CT scan with reported outcome for the detection of anastomotic leakage. Exclusion criteria were cohort of fewer than five patients, other gastrointestinal surgery, no anastomosis, and radiological imaging other than CT.

RESULTS

Eight studies, including 221 abdominal CT scans, fulfilled the inclusion criteria. Overall, the methodological quality of the studies was poor. The overall sensitivity of CT scanning to diagnose leakage was 0.68 (95 % confidence interval 0.59-0.75) for colonic resection. Data on the sequelae of false-negative CT scanning was not available.

CONCLUSION

There is limited good-quality evidence to determine the value of CT scans in the detection of anastomotic leakage. To prevent delay in diagnosis and appropriate treatment of anastomotic leakage, the relatively low sensitivity of CT scanning must be taken into account.

Burst strength testing of porcine intestinal anastomoses following negative pressure therapy

The effect of negative pressure therapy (NPT; The ABThera™ Open Abdomen Negative Pressure Therapy System, KCI USA, Inc., San Antonio, TX) on the integrity of small intestinal anastomoses was evaluated using in situ burst strength testing in a domestic pig model. In each of 3 swine, 8 anastomoses were created, 4 using sutures and 4 using staples. After 24 hours of continuous NPT, each anastomosis was subjected to burst strength testing in situ. Mean ratios of burst strength of sutured anastomoses to baseline intraluminal pressure were 9.0 to 10.9. Stapled anastomoses had significantly lower burst strength than sutured anastomoses, but mean values were still at least 4.6 times greater than baseline. No differences were seen between anastomoses that were located in close proximity with treatment and those remotely placed or when measured with negative pressure on or off at burst assessment. NPT had no acute adverse effect on intestinal anastomoses in swine.