Altered microperfusion at the rectal stump is predictive for rectal anastomotic leak

Intestinal Mucosal and Serosal Microcirculation at the Planned Anastomosis during Abdominal Surgery

INTRODUCTION

Intestinal blood flow is often named as a key factor in the pathophysiology of anastomotic leakage. The distribution between mucosal and serosal microperfusion during surgery remains to be elucidated.

OBJECTIVE

The aim of this study was to assess if the mucosal microcirculation of the intestine is more vulnerable to a surgical hit than the serosal microcirculation during surgery.

METHODS

In an observational cohort study (n = 9 patients), the microcirculation of the bowel serosa and mucosa was visualized with incident dark-field imaging during surgery. At the planned anastomosis, the following microcirculatory parameters were determined: microvascular flow index (MFI), percentage of perfused vessels (PPV), perfused vessel density (PVD), and total vessel density (TVD). Data are presented as median (interquartile range [IQR]).

RESULTS

Perfusion parameters and vessel density were significantly higher for the mucosa than the serosal microcirculation at the planned site for anastomosis or stoma. Mucosal MFI was 3.00 (IQR 3.00-3.00) compared to a serosal MFI of 2.75 (IQR 2.21-2.94), p = 0.03. The PPV was 99% (IQR 98-100) versus 92% (IQR 66-94), p = 0.01. The TVD was 16.77 mm/mm2 (IQR 13.04-18.01) versus 10.42 mm/mm2 (IQR 9.36-11.81), p = 0.01, and the PVD was 15.44 mm/mm2 (IQR 13.04-17.78) versus 9.02 mm/mm2 (IQR 6.43-9.43), p = 0.01.

CONCLUSIONS

The mucosal microcirculation was preserved, while lower perfusion of the serosa was found at the planned anastomosis or stoma during surgery. Further research is needed to link our observations to the clinically relevant endpoint of anastomotic leakage.

Effect of oxygen-producing suture material on hypoxic colonic anastomoses in an experimental model

Background

Anastomotic leak remains a significant cause of morbidity and mortality after colorectal surgery. Among multiple risk factors considered, hypoxia–ischaemia is considered to be a primary cause of intestinal anastomotic leakage. The aim of this experimental study was to assess safety, usability for surgical tasks, and efficacy of a newly developed oxygen‐producing suture material in the healing of colonic anastomoses under critical conditions.

Methods

An oxygen‐producing suture material was produced that is capable of releasing oxygen directly into the surrounding tissue. Off‐the‐shelf sutures loaded with calcium peroxide nano‐crystals and covered with poly(d,l‐lactide‐co‐glycolide) were assessed in vitro and in a rat model of hypoxic colonic anastomosis.

Results

In vitro assessment showed that these sutures can increase oxygen levels in a hypoxic environment. Potential oxygen byproducts did not seem to have a negative impact on the viability of intestinal cells. The use of oxygen‐producing sutures in vivo resulted in increased tissue oxygen saturation, measured by visible light spectroscopy, and increased mechanical stability of the anastomosis.

Conclusion

Oxygen‐producing suture material increased tissue oxygen saturation and mechanical stability of colonic anastomosis in a rat model.

Clinical utility of transanal indocyanine green near-infrared fluorescence imaging for evaluation of colorectal anastomotic perfusion

BACKGROUND

Although indocyanine green (ICG) fluorescence imaging has been reported to be useful for assessing colorectal perfusion, unstable quantification remains an issue. We performed ICG fluorescence observation from the luminal side and examined the usefulness of the transanal approach.

METHODS

A total of 69 patients who underwent left-side colon surgery were enrolled in this cohort study. After the anastomosis had been constructed, ICG 0.2 mg/kg was injected intravenously. The anastomotic site was then observed by a scope inserted transanally. The following items were examined in the areas of the anastomotic site with the highest- and lowest-fluorescence intensity: maximum fluorescence (Fmax), time from ICG injection to Fmax (Tmax), time from start of dyeing to Fmax (ΔT), and the contrast pattern of the mucosa.

RESULTS

Anastomotic leakage (AL) occurred in nine cases. Tmax and ΔT values of the lowest-fluorescence area in the distal intestine showed significant differences in the cases with AL (P = 0.015 and P = 0.040, respectively). Regarding the contrast pattern of the mucosa of the lowest-fluorescence area in the proximal and distal intestine, the patients in whom the vessels were not depicted in the area had a significantly higher incidence of AL than those in whom vessels were depicted in the area (P = 0.031 and P = 0.030, respectively). Some of the areas in which vessels were not depicted by ICG fluorescence observation from the luminal side corresponded to the points of leakage. There were heterogeneous changes that might not be grasped by observation from the serosal side.

CONCLUSION

Transanal ICG fluorescence imaging can evaluate perfusion over the entire circumference of the anastomosis in detail and aid in assessing the risk of AL. Therefore, the examination of the detailed low-perfusion area enables us to take measures for AL and to search for safer operative managements.

The Aortic Calcification Index is a risk factor associated with anastomotic leakage after anterior resection of rectal cancer

AIM

Anastomotic leakage (AL) is one of the most feared postoperative complications after anterior resection (AR) of rectal cancer. An adequate blood supply at the anastomotic site is regarded as a prerequisite for healing. We hypothesize that the Aortic Calcification Index (ACI) might reflect the severity of atherosclerosis in patients, and thereby be a risk factor for AL.

METHOD

AL was investigated retrospectively according to the definition of the International Study Group of Rectal Cancer in 423 rectal cancer patients who underwent anterior rectal resection. The ACI was measured by preoperative abdominal CT scan. The cross-section of the aorta was evenly divided into 12 sectors, the number of calcified sectors was counted as the calcification score of each slice. Lasso logistic regression and multivariate regression analysis were used to identify risk factors for AL.

RESULTS

The percentage of AL after AR was 7.8% (33/423); the mortality of patients who sustained a leak was 3.0% (1/33). Patients with a high ACI had a significantly higher percentage of AL than patients with low ACI (11.2% vs 5.6%, P = 0.04). Among patients with AL, a higher ACI was associated with greater severity of AL (the ACI of patients with grade A leakage, grade B leakage and grade C leakage was 0.5% ± 0.2%, 11.5% ± 9.2% and 24.2% ± 21.7%, respectively; P = 0.008). After risk adjustment, multivariate regression analysis showed that a higher ACI was an independent risk factor for AL (OR 2.391, P = 0.04).

CONCLUSION

A high ACI might be an important prognostic factor for AL after AR for rectal cancer. Confirmatory studies are required.

Mechanotechnical faults and particular issues of anastomotic complications following robot-assisted anterior resection in 968 rectal cancer patients

BACKGROUND

As most risk factors for anastomotic complications (AC) in rectal cancer patients appear to be noncorrectable, it is needed to find the correctable causes. Additionally, the outcomes of indocyanine-green fluorescence imaging (IFI) and robot-stapled anastomosis have yet been undetermined.

METHODS

This study retrospectively analyzed 968 consecutive patients with rectal cancer, who underwent curative robot-assisted anterior resections between 2010 and 2018. IFI parameters and stapling features in the surgical records were reviewed, and reconfirmed.

RESULTS

AC occurred in 54 patients (5.6%), 34 (3.5%) with anastomotic leakage (AL) and 24 (2.5%) with anastomotic stenosis (AS). Mechanotechnical faults including defective stapling configurations, including angles lesser than or equal to 150° and outer deviation (more than half from the center of the circle) of linear staples, between the two linear staples were independently associated with AL (P < .001 each). IFI significantly reduced AL rate (2.5% vs 5.3%, P = .029) and AS rate (2% vs 18.8%, P = .006), respectively. Robot linear stapling enabled to maintain the obtuse angle during consecutive staplings and reduced console time. AL and AS were independent risk factors for disease-free survival (P = .02) and local recurrence (P = .03), respectively.

CONCLUSIONS

AC were associated with some correctable causes, namely, mechanotechnical errors and lack of use of IFI.

Spectrophotometric assessment of bowel perfusion during low anterior resection: a prospective study

Good perfusion of the bowel and a tension-free anastomosis are the two main prerequisites for an uneventful anastomotic healing in rectal surgery. This prospective cohort study investigates the noninvasive intraoperative spectrophotometric assessment of the bowel perfusion using a device called “Oxygen to See” (O2C^®). Forty patients, planned for low anterior resection, were prospectively enrolled in this study to undergo an intraoperative spectrophotometric assessment of the bowel. Three different O2C^® parameters were collected from the colonic and the rectal stumps before fashioning the anastomosis: SO2 (capillary venous oxygen saturation), rHb (relative hemoglobin amount), and flow (blood flow velocity). Bowel perfusion was also assessed with the cold-steel-test (CST), which involves severing the colic marginal artery of Drummond at the tip of the colon stump. The data collected from the spectrophotometric measurement and the CST were analyzed for correlation of both methods with respect to each other and to the outcome of the anastomosis. Nine patients were excluded due to different reasons, thus leaving 31 patients for statistical analysis. Three flow parameters collected at the colonic stump significantly predicted an anastomotic leak (p: 0.0057; p: 0.0250; p: 0.0404). One rHb parameter collected at the rectal stump correlated weakly with the anastomotic outcome (p: 0.0768). The CST did not correlate significantly with anastomotic leak (p: 0.1195), but showed significant correlations to some rHb values. Intraoperative noninvasive spectrophotometric measurement is feasible and could be a useful method in assessing bowel perfusion before fashioning a colorectal anastomosis.

Reducing anastomotic leak in colorectal surgery: The old dogmas and the new challenges

Anastomotic leak (AL) constitutes a significant issue in colorectal surgery, and its incidence has remained stable over the last years. The use of intra-abdominal drain or the use of mechanical bowel preparation alone have been proven to be useless in preventing AL and should be abandoned. The role or oral antibiotics preparation regimens should be clarified and compared to other routes of administration, such as the intravenous route or enema. In parallel, preoperative antibiotherapy should aim at targeting collagenase-inducing pathogens, as identified by the microbiome analysis. AL can be further reduced by fluorescence angiography, which leads to significant intraoperative changes in surgical strategies. Implementation of fluorescence angiography should be encouraged. Progress made in AL comprehension and prevention might probably allow reducing the rate of diverting stoma and conduct to a revision of its indications.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) might increase the risk of anastomotic leakage compared to HIPEC: an experimental study

BACKGROUND

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) and hyperthermic intraperitoneal chemotherapy (HIPEC) are technics proposed to treat patients with peritoneal carcinomatosis, in different settings. There is some concern about an over-risk of anastomotic leakage (AL) with PIPAC jeopardizing a combination with cytoreductive surgery. This study used a healthy swine model to compare the postoperative AL rate between PIPAC and HIPEC with digestive resection and to analyze macrocirculation and microcirculation parameters.

METHODS

Segmental colonic resection with a handsewn anastomosis was performed on 16 healthy pigs; 8 pigs had a PIPAC procedure with 7.5 mg/m² cisplatin (PIPAC group), and 8 pigs had a closed HIPEC procedure with 70 mg/m² cisplatin and 42 °C as the target intraperitoneal temperature (HIPEC group). Pigs were kept alive for 8 days, then sacrificed and autopsied to look for AL, which was defined as local abscess or digestive fluid leakage when pressure was applied to the anastomosis. Food intake, weight, and core temperature were monitored postoperatively. Macrocirculation (heart rate, systolic blood pressure) and microcirculation parameters (percentage of perfused vessels, perfused vessels density, DeBacker score) were evaluated intraoperatively at five timepoints. Results were compared between pigs with AL and those without.

RESULTS

The HIPEC group had no AL, but 3 of 8 pigs (37.5%) had AL in the PIPAC group (p = 0.20). Heart rate and core temperature showed perioperative increases in the HIPEC group. Intraoperatively, heart rate was higher in the HIPEC group at the two last timepoints (123 vs. 93 bpm, p = 0.031, and 110 vs. 85 bpm, p = 0.010, at timepoints 3 and 4, respectively). Other macrocirculatory and microcirculatory parameters showed no significant differences.

CONCLUSION

In this healthy swine model, PIPAC might have increased AL incidence compared to HIPEC. This potential over-risk did not seem to be related to changes in the microcirculation. PIPAC should probably not be used with digestive resection and should be avoided in cases of perioperative serosal injury.

Serial CRP levels following oesophagectomy: a marker for anastomotic dehiscence

BACKGROUND

Following oesophagectomy, the most concerning complication is that of anastomotic leak (AL). Prompt diagnosis and intervention are crucial to facilitate an optimal outcome. Other complications, particularly respiratory, are not infrequent. Early identification of AL versus other sources of the inflammatory response can be problematic.

AIMS

To evaluate the role of serial CRP as a prognosticator for oesophagogastric AL.

METHODS

All oesophagectomies carried out at our institution from 2010 to 2017 were included. Serial C-reactive protein (CRP) and white cell count (WCC) were recorded pre-operatively and on each consecutive day up to day 10 post-op. All complications were recorded and the timing of diagnosis compared with serial CRP and WCC measurements to determine any correlation.

RESULTS

One hundred and two patients underwent oesophagectomy (84 male, 18 female) with a mean age of 62.5 years (± 9.8). Forty-seven patients developed post-operative complications, with pulmonary (n = 28) the most common. There were 5 cases of AL. Patients in the AL group (n = 5) had a significantly higher mean CRP compared to those who did not develop AL (n = 97) pre-operatively (50 vs. 14, p = 0.046), on post-op day 3 (300 vs. 218, p = 0.02) and on post-op day 4 (279 vs. 184, p = 0.009). There was no significant difference in mean daily CRP between patients with pulmonary complications (PC, n = 29) and those who did not develop complications (NC, n = 54).

CONCLUSIONS

Elevated CRP may be a useful marker in facilitating the prompt diagnosis of AL following oesophagectomy. Serial CRP may not contribute to identifying lower respiratory tract infections, partly as a result of the pro-inflammatory response following surgery.

Predictive risk factors for anastomotic leakage after anterior resection of rectal cancer in elderly patients over 80 years old: an analysis of 288 consecutive patients

Background

Anastomotic leakage (AL) is a common complication after anterior resection of rectal cancer. Few studies have been conducted to determine whether the traditional predictors of AL can be applied to elderly patients (age ≥ 80) undergoing anterior resection (AR) or low anterior resection (LAR) of rectal cancer. This study was designed to explore the predictive factors for AL after anterior resection of rectal cancer in patients over 80 years old.

Methods

From January 2007 to May 2019, consecutive elderly (age ≥ 80) rectal cancer patients undergoing AR or LAR at our institution were systematically reviewed. The general information, perioperative outcomes, and comorbidities were collected.

Results

A total of 288 consecutive patients were included in this study. The average age was 82.8 ± 2.4 years, and 30 (10.4%) patients developed AL. The univariate analyses showed that neoadjuvant therapy (50.0% vs. 27.9%, P = 0.013), the number of stapler firings ≥ 3 (60.0% vs. 36.0%, P = 0.011), and coronary heart disease (CHD) (46.7% vs. 17.8%, P < 0.001) were associated with an increased incidence of AL. The multivariate analysis showed that the number of stapler firings ≥ 3 (OR = 4.77, 95% CI = 1.33–15.21, P = 0.035) and CHD (OR = 8.33, 95% CI = 1.94–13.05, P = 0.003) were independent risk factors for AL.

Conclusion

The number of stapler firings ≥ 3 and CHD were independent risk factors for AL in elderly patients (age ≥ 80) with rectal cancer. A temporary ileostomy or the Hartmann procedure is recommended for patients with CHD, male patients, patients considered to be obese, and patients with a lower tumor location, which may increase the number of stapler firings. Certainly, we recommend that the number of stapler firings should be minimized to alleviate the economic and physical burden of patients.

End-to-end intestinal anastomosis using a novel biodegradable stent for laparoscopic colonic surgery: a multicenter study

PURPOSE

Our animal studies have demonstrated the safety and feasibility of end-to-end intestinal anastomosis using a stent for laparoscopic colonic surgery. Therefore, we designed a non-inferiority trial to investigate the outcomes of stent anastomosis (SA) vs. those of conventional hand-sewn anastomosis (CA).

METHODS

A multicenter randomized controlled trial was conducted between December, 2016 and April, 2018. The primary outcome was the healing condition of the anastomoses, evaluated by endoscopy 6 months postoperatively. The secondary outcomes were the anastomotic completion time, anastomotic leak, intestinal obstruction, peritoneal effusion, and bleeding. Quality of life (QOL) was evaluated by questionnaires.

RESULTS

The subjects of this study were 60 patients, randomly divided into a SA group (n = 30) and a CA group (n = 30). There were no differences in anastomotic healing conditions (P = 1.00). The stent procedure was associated with a significantly shorter anastomosis time than the hand-sewn anastomosis (13.517 ± 4.281 vs. 20.333 ± 2.998 min, respectively; P < 0.001). There were no significant differences in anastomotic leakage, intestinal obstruction, peritoneal effusion, or bleeding between the groups. Questionnaires revealed almost no discrepancy between baseline QOL scores and those assessed 2, 4, 8, 12, and 24 weeks postoperatively in either group.

CONCLUSIONS

Intestinal anastomosis with a stent is a non-inferior strategy for laparoscopic colonic surgery, which requires less time for the anastomosis.

Clinical Significance of Pelvic Peritonization in Laparoscopic Dixon Surgery

Background:

Pelvic floor peritoneum reconstruction is a key step in various standard resections for open radical rectal cancer. However, during endoscopic surgery, most surgeons do not close the pelvic floor peritoneum. This study aims to evaluate the efficacy of pelvic peritonization during laparoscopic Dixon surgery using an observational study.

Methods:

A total of 189 patients, who underwent laparoscopic Dixon surgery at Tianjin Union Medical Center, China, were analyzed retrospectively. All of the cases were divided into two groups according to the differences of surgical procedure. The 92 patients in Group A (observation group) underwent pelvic peritonization and the 97 patients in Group B (control group) did not undergo this procedure. Postoperative complications were observed in the two groups, compared, and analyzed using the Chi-square or Fisher's exact test.

Results:

The incidence of anastomotic leakage was significantly lower in Group A than in Group B (P = 0.014). A significant difference was found in the postoperative short-term (P = 0.029) and long-term (P = 0.029) ileus rates between the two groups, with Group A exhibiting a lower rate than Group B. Patients in Group A had significantly lower rates of postoperative infections than those in Group B (χ² = 7.606, P = 0.006; χ² = 4.464, P = 0.035). Patients in Group A had significantly lower rates of deep venous thrombosis than those in Group B (χ² = 8.531, P = 0.003).

Conclusions:

Pelvic peritonization effectively reduces postoperative complications, such as anastomotic leakage, which warrants its increased use in laparoscopic surgery.

Laser speckle contrast imaging and quantitative fluorescence angiography for perfusion assessment

PURPOSE

Indocyanine green fluorescence angiography (ICG-FA) is an established technique for assessment of intestinal perfusion during gastrointestinal surgery, whereas quantitative ICG-FA (q-ICG) and laser speckle contrast imaging (LSCI) are relatively unproven. The study aimed to investigate whether the techniques could be applied interchangeably for perfusion assessment.

METHODS

Nineteen pigs underwent laparotomy, two minor resections of the small bowel, and anastomoses. Additionally, seven pigs had parts of their stomach and small intestine de-vascularized. Data was also collected from an in vivo model (inferior caval vein measurements in two additional pigs) and an ex vivo flow model, allowing for standardization of experimental flow, distance, and angulation. Q-ICG and LSCI were performed, so that regions of interest were matched between the two modalities in the analyses, ensuring coverage of the same tissue.

RESULTS

The overall correlation of q-ICG and LSCI evaluated in the porcine model was modest (rho = 0.45, p < 0.001), but high in tissue with low perfusion (rho = 0.74, p < 0.001). Flux values obtained by LSCI from the ex vivo flow model revealed a decreasing flux with linearly increasing distance as well as angulation to the model. The Q-ICG perfusion values obtained varied slightly with increasing distance as well as angulation to the model.

CONCLUSIONS

Q-ICG and LSCI cannot be used interchangeably but may supplement each other. LSCI is profoundly affected by angulation and distance. In comparison, q-ICG is minimally affected by changing experimental conditions and is more readily applicable in minimally invasive surgery.

Intraoperative angiography with indocyanine green to assess anastomosis perfusion in patients undergoing laparoscopic colorectal resection: results of a multicenter randomized controlled trial

BACKGROUND

Insufficient vascular supply is one of the main causes of anastomotic leak in colorectal surgery. Intraoperative indocyanine-green (ICG) angiography has been shown to provide information on tissue perfusion, identifying a well-perfused location for colonic and rectal transections, and thus possibly reducing the leak rate. Aim of this study was to evaluate the usefulness of intraoperative assessment of anastomotic perfusion using ICG angiography in patients undergoing left-sided colon or rectal resection with colorectal anastomosis.

METHODS

This randomized trial involved 252 patients undergoing laparoscopic left-sided colon and rectal resection randomized 1:1 to intraoperative ICG or to subjective visual evaluation of the bowel perfusion without ICG. The primary aim was to assess whether ICG angiography could lead to a reduction in anastomotic leak rate. Secondary outcomes were possible changes in the surgical strategy and postoperative morbidity.

RESULTS

After randomization, 12 patients were excluded. Accordingly, 240 patients were included in the analysis; 118 were in the study group, and 122 in the control group. ICG angiography showed insufficient perfusion of the colic stump, which led to extended bowel resection in 13 cases (11%). An anastomotic leak developed in 11 patients (9%) in the control group and in 6 patients (5%) in the study group (p = n.s.).

CONCLUSIONS

Intraoperative ICG fluorescent angiography can effectively assess vascularization of the colic stump and anastomosis in patients undergoing colorectal resection. This method led to further proximal bowel resection in 13 cases, however, there was no statistically significant reduction of anastomotic leak rate in the ICG arm.

CLINICAL TRIAL

ClinicalTrials.gov NCT02662946.

Indocyanine green fluorescence imaging to reduce the risk of anastomotic leakage in laparoscopic low anterior resection for rectal cancer: a propensity score-matched cohort study

BACKGROUND

Recent studies have shown the potential benefit of indocyanine green fluorescence imaging (ICG-FI) in lowering the anastomotic leakage (AL) rates by changing the surgical plan. The aim of this study was to evaluate the effect of ICG-FI on the AL rates in laparoscopic low anterior resection (LAR) for rectal cancer.

METHODS

From September 2014 to December 2017, data from patients who underwent laparoscopic LAR for rectal cancer were collected and analyzed. The primary endpoint was the AL rate within 30 days after surgery. The incidence of AL in patients who underwent ICG (ICG-FI group) was compared with that in patients who did not undergo ICG (non-ICG-FI group) using propensity score matching.

RESULTS

Data from 550 patients were collected from 3 institutions. A total of 211 patients were matched in both groups by the propensity score. ICG-FI shifted the point of the proximal colon transection line toward the oral side in 12 patients (5.7%). The AL rates of Clavien-Dindo (CD) grade ≥ II and ≥ III were 10.4% (22/211) and 9.5% (20/211) in the non-ICG-FI group and 4.7% (10/211) and 2.8% (6/211) in the ICG-FI group, respectively. ICG-FI significantly reduced the AL rate of CD grade ≥ II and ≥ III (odds ratio (OR) 0.427; 95% confidence interval (CI) 0.197-0.926; p = 0.042 and OR 0.280; CI 0.110-0.711; p = 0.007, respectively). The rate of reoperation was significantly lower (OR 0.192; CI 0.042-0.889; p = 0.036) and the postoperative hospital stay significantly shorter (mean difference 2.62 days; CI 0.96-4.28; p = 0.002) in the ICG-FI group than in the non-ICG-FI group.

CONCLUSIONS

ICG-FI was associated with significantly lower odds of AL in laparoscopic LAR for rectal cancer.

CLINICAL TRIAL

The study was registered with the Japanese Clinical Trials Registry as UMIN000032654.

The Predictive Value of Pulse Wave Velocity for Anastomotic Leakage After Colorectal Surgery

BACKGROUND

Arterial perfusion defects are a risk factor for anastomotic leakage (AL) following colorectal surgery. Measuring arterial stiffness using pulse wave velocity (PWV) is known to reflect the performance of the arterial network. The objective of this study was to assess the predictive value of PWV for AL after colorectal surgery.

METHODS

A prospective monocentric study was conducted on all consecutive patients who underwent colorectal surgery scheduled between March 1, 2016 and May 1, 2017. Patients were divided into two groups according to the PWV which was measured preoperatively using the pOpmètre^® device: PWV+ (PWV > 10 m/s) and PWV- (PWV ≤ 10 m/s). We then compared the PWV+ and PWV- groups. The primary endpoint was the AL rate.

RESULTS

A total of 96 patients were studied, including 60 in the PWV- group and 36 in the PWV+ group. Patients in the PWV+ group were more at risk of presenting with AL than those in the PWV- group (6.25 vs 0%) (p = 0.002). There was no difference in immediate postoperative complications between the two groups apart from the length of hospital stay. PWV predicted the appearance of AL with a sensitivity of and a negative predictive value of 100%.

CONCLUSION

Measuring PWV could be a used as a predictive examination in the early detection of AL after colorectal surgery.

Near-infrared fluorescence image-guidance in anastomotic colorectal cancer surgery and its relation to serum markers of anastomotic leakage: a clinical pilot study

OBJECTIVE

Near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) might help reduce anastomotic leakage (AL) after colorectal surgery. This pilot study aims to analyze whether a relation exists between measured fluorescence intensity (FI) and postoperative inflammatory markers of AL, C-reactive protein (CRP), Intestinal fatty-acid binding protein (I-FABP), and calprotectin, to AL, in order to evaluate the potential of FI to objectively predict AL.

METHODS

Patients scheduled for anastomotic colorectal cancer surgery were eligible for inclusion in this prospective pilot study. During surgery, at three time points (after bowel devascularization; before actual transection; after completion of anastomosis) a bolus of 0.2 mg/kg ICG was administered intravenously for assessment of bowel perfusion. FI was scored in scale from 1 to 5 based on the operating surgeon's judgment (1 = no fluorescence visible, 5 = maximum fluorescent signal). The complete surgical procedure was digitally recorded. These recordings were used to measure FI postoperatively using OsiriX imaging software. Serum CRP, I-FABP, and calprotectin values were determined before surgery and on day 1, 3, and 5 postoperative; furthermore, the occurrence of AL was recorded.

RESULTS

Thirty patients (n = 19 males; mean age 67 years; mean BMI 27.2) undergoing either laparoscopic or robotic anastomotic colorectal surgery were included. Indication for surgery was rectal-(n = 10), rectosigmoid-(n = 2), sigmoid-(n = 10), or more proximal colon carcinomas (n = 8). Five patients (16.7%) developed AL (n = 2 (6.6%) grade C according to the definition of the International Study group of Rectal Cancer). In patients with AL, the maximum fluorescence score was given less often (P = 0.02) and a lower FI compared to background FI was measured at 1st assessment (P = 0.039). However, no relation between FI and postoperative inflammatory parameters could be found.

CONCLUSION

Both subjective and measured FI seem to be related to AL. In this study, no relation between FI and inflammatory serum markers could yet be found.

Effects of Thoracic Epidural Anaesthesia on the Serosal Microcirculation of the Human Small Intestine

BACKGROUND

The effect of thoracic epidural analgesia (TEA) on splanchnic blood flow during abdominal surgery remains unclear. The purpose of this study was to examine whether the hemodynamic effects of TEA resulted in microcirculatory alterations to the intestinal serosa, which was visualized using incident dark-field (IDF) videomicroscopy.

METHODS

An observational cohort study was performed. In 18 patients, the microcirculation of the intestinal serosa was visualized with IDF. Microcirculatory and hemodynamic measurements were performed prior to (T1) and after administering a bolus of levobupivacaine (T2). If correction of blood pressure was indicated, a third measurement was performed (T3). The following microcirculatory parameters were calculated: microvascular flow index, proportion of perfused vessels, perfused vessel density and total vessel density. Data are presented as median [IQR].

RESULTS

Mean arterial pressure decreased from 73 mmHg (68-83) at T1 to 63 mmHg (±11) at T2 (p = 0.001) with a systolic blood pressure of 114 mmHg (98-128) and 87 (81-97), respectively (p = 0.001). The microcirculatory parameters of the bowel serosa, however, were unaltered. In seven patients, blood pressure was corrected to baseline values from a MAP of 56 mmHg (55-57), while microcirculatory parameters remained constant.

CONCLUSION

We examined the effects of TEA on the intestinal serosal microcirculation during abdominal surgery using IDF imaging for the first time in patients. Regardless of a marked decrease in hemodynamics, microcirculatory parameters of the bowel serosa were not significantly affected.

TRIAL REGISTRY NUMBER

ClinicalTrials.gov identifier NCT02688946.

Radiation-induced injury on surgical margins: a clue to anastomotic leakage after rectal-cancer resection with neoadjuvant chemoradiotherapy?

Background

Few studies on anastomotic condition after rectal-cancer resection and its effect on anastomotic leakage (AL) are available up to now. This study aimed to investigate potential radiation-induced injury left on surgical margins of anterior resection after neoadjuvant chemoradiotherapy (nCRT) and its association with AL.

Methods

We retrospectively identified 161 consecutive patients who underwent anterior resection with nCRT, neoadjuvant chemotherapy without radiation (nCT) or no neoadjuvant therapy between 2014 and 2015. Tissue samples of resection margins were assessed using a specific histopathological score and microvessel density in submucosa. Propensity score matching was used to balance the baseline characteristics. Association between AL and histopathological features was analysed.

Results

AL occurred in 13 of 54 patients undergoing nCRT, 5 of 48 patients undergoing nCT and 7 of 59 patients without neoadjuvant therapy. Comparisons after matching showed median (range) histopathological scores as follows: 3 (0–8) vs 0 (0–3) vs 0 (0–2) for the proximal margin (P < 0.001); 4 (2–9) vs 0 (0–4) vs 0 (0–3) for the distal margin (P < 0.001). Correspondingly, mean (SD) microvessel densities were as follows: 21.7 (7.9) vs 27.2 (8.6) vs 27.3 (9.4) for the proximal margin (P = 0.003); 18.1 (9.3) vs 25.2 (12.9) vs 24.9 (7.4) for the distal margin (P < 0.001). Among patients undergoing nCRT, AL was associated with increased histopathological score (P = 0.003) and decreased microvessel density (P = 0.004) on the proximal margin.

Conclusions

Surgical margins of rectal-cancer resection are exposed to certain radiation-induced injury after nCRT. AL is associated with aggravated radiation damage on the proximal margin.

Rate of Anastomotic Leakage After Rectal Anastomosis Depends on the Definition: Pelvic Abscesses are Significant

BACKGROUND AND AIMS

The International Study Group of Rectal Cancer has proposed that a pelvic abscess in the proximity of the anastomosis is considered an anastomotic leak, whether or not its point of origin is detectable. This study describes how the inclusion of pelvic abscesses alters the leakage rate.

MATERIAL AND METHODS

Risk factors and postoperative complications in patients with visible anastomotic leakage ("direct leakage"), pelvic abscesses alone in the vicinity of a visibly intact anastomosis ("abscess leakage"), and no leakage were retrospectively evaluated.

RESULTS

In total, 341 patients operated with anterior resections and who received an anastomosis within 15 cm as measured from the anal verge were included. A total of 37 patients (10.9%) had direct leakage, 13 (3.8%) had abscess leakage, and 291 (85.3%) had no leakage. The overall anastomotic leakage rate was 14.7% (50 patients). In accordance with the grading system outlined by International Study Group of Rectal Cancer, 7 patients (2.1%) experienced Grade A leakage, 19 (5.6%) Grade B, and 24 (7.0%) Grade C. Direct leak patients had more often a reoperation due to anastomotic complications (odds ratio = 19.7, p = 0.001), a permanent stoma (odds ratio = 28.5, p = 0.001), and a longer hospital stay than abscess leak patients (29.0 vs 15.5 days, p = 0.030).

CONCLUSION

Abscess leakage accounted for over one-fourth of the overall leakage rate, raising the leakage rate. Direct leak patients were at a higher risk of requiring a reoperation, permanent stoma, and longer hospital stay than abscess leak patients. Abscess leak patients were at a greater risk for a urinary tract infection, wound infection, and postoperative intestinal obstruction than non-leak patients.

Can sidestream dark field (SDF) imaging identify subtle microvascular changes of the bowel during colorectal surgery?

BACKGROUND

Recognition of a non-viable bowel during colorectal surgery is a challenging task for surgeons. Identifying the turning point in serosal microcirculatory deterioration leading up to a non-viable bowel is crucial. The aim of the present study was to determine whether sidestream darkfield (SDF) imaging can detect subtle changes in serosal microcirculation of the sigmoid after vascular transection during colorectal surgery.

METHODS

A prospective observational clinical study was performed at a single medical centre. All eligible participants underwent laparoscopic sigmoid resection and measurements were taken during the extra-abdominal phase. Microcirculation was measured at the transected bowel and 20 cm proximal to this point. Microcirculatory parameters such as Microvascular Flow Index (MFI), proportion of perfused vessels (PPV), perfused vessel density (PVD), total vessel density (TVD) and the Heterogeneity Index were determined. Data are presented as median (interquartile range) or mean ± standard deviation.

RESULTS

A total of 60 SDF images were acquired for 10 patients. Perfusion parameters and perfused vessel density were significantly lower at the transected bowel compared with the non-transected measurements [MFI 2.29 (1.96-2.63) vs 2.96 (2.73-3.00), p = 0.007; PPV 74% (55-83) vs 94% (86-97), p = 0.007; and PVD 7.61 ± 2.99 mm/mm² versus 10.67 ± 1.48 mm/mm², p = 0.009]. Total vessel density was similar between the measurement locations.

CONCLUSIONS

SDF imaging can identify changes of the bowel serosal microcirculation. Significantly lower serosal microcirculatory parameters of the vascular transected bowel was seen compared with the non-transected bowel. The ability of SDF imaging to detect subtle differences holds promise for future research on microvascular cut-off values leading to a non-viable bowel.

Quantitative perfusion assessment of intestinal anastomoses in pigs treated with glucagon-like peptide 2

PURPOSE

Despite exhaustive research and improvement of techniques, anastomotic leakage remains a frequent complication in gastrointestinal surgery. As leakage is associated with poor perfusion, reliable objective methods to assess anastomotic perfusion are highly demanded. In addition, such methods enable evaluation of interventions that may improve anastomotic perfusion. Glucagon-like peptide 2 (GLP-2) is an enteroendocrine hormone that regulates mid-gut perfusion. In the present study, we aimed to explore if quantitative perfusion assessment with indocyanine green (q-ICG) could detect an increase in porcine anastomotic perfusion after treatment with GLP-2.

METHODS

Nineteen pigs had two small bowel resections followed by anastomosis. Blinded to all investigators, animals were randomized to receive GLP-2 or placebo. Anastomotic perfusion was assessed at baseline, 30 min after injection of GLP-2/placebo, and after 5 days of treatment. Anastomotic strength and healing were evaluated by bursting pressure and histology.

RESULTS

Q-ICG detected a significantly higher increase in anastomotic perfusion (p < 0.05) in animals treated with GLP-2, compared with placebo. No significant differences in anastomotic strength or healing were found.

CONCLUSIONS

Q-ICG is a promising tool for perfusion assessment in gastrointestinal surgery and opens new opportunities in research of factors that may influence anastomotic healing, but further research is warranted to evaluate the effects of GLP-2 on anastomotic healing.

Quantitative analysis of colon perfusion pattern using indocyanine green (ICG) angiography in laparoscopic colorectal surgery

Purpose

This study aimed to quantitatively evaluate colon perfusion patterns using indocyanine green (ICG) angiography to find the most reliable predictive factor of anastomotic complications after laparoscopic colorectal surgery.

Methods

Laparoscopic fluorescence imaging was applied to colorectal cancer patients (n = 86) from July 2015 to December 2017. ICG (0.25 mg/kg) was slowly injected into peripheral blood vessels, and the fluorescence intensity of colonic flow was measured sequentially, producing perfusion graphs using a video analysis and modeling tool. Colon perfusion patterns were categorized as either fast, moderate, or slow based on their fluorescence slope, T_1/2MAX and time ratio (TR = T_1/2MAX/T_MAX). Clinical factors and quantitative perfusion factors were analyzed to identify predictors for anastomotic complications.

Results

The mean age of patients was 65.4 years, and the male-to-female ratio was 63:23. Their operations were laparoscopic low anterior resection (55 cases) and anterior resection (31 cases). The incidence of anastomotic complication was 7%, including colonic necrosis (n = 1), anastomotic leak (n = 3), delayed pelvic abscess (n = 1), and delayed anastomotic dehiscence (n = 1). Based on quantitative analysis, the fluorescence slope, T_1/2MAX, and TR were related with anastomotic complications. The cut-off value of TR to categorize the perfusion pattern was determined to be 0.6, as shown by ROC curve analysis (AUC 0.929, P < 0.001). Slow perfusion (TR > 0.6) was independent factor for anastomotic complications in a logistic regression model (OR 130.84; 95% CI 6.45–2654.75; P = 0.002). Anastomotic complications were significantly correlated with the novel factor TR (> 0.6) as the most reliable predictor of perfusion and anastomotic complications.

Conclusions

Quantitative analysis of ICG perfusion patterns using T_1/2MAX and TR can be applied to detect segments with poor perfusion, thereby reducing anastomotic complications during laparoscopic colorectal surgery.

Male sex and history of ischemic heart disease are major risk factors for anastomotic leakage after laparoscopic anterior resection in patients with rectal cancer

Background

Anastomotic leakage (AL) is the most serious and common complication of surgery for rectal cancer, and associated risk factors remain unknown despite developments in laparoscopic surgery. The present study aimed to determine risk factors for AL after laparoscopic anterior resection (AR) of rectal cancer.

Methods

This retrospective cohort study extracted information from a prospective database of all consecutive colorectal resections that proceeded at Nippon Medical School Hospital between January 2011 and December 2015 (n = 865). We identified 154 patients with rectal cancer treated by elective laparoscopic AR with anastomosis using primary double-stapling. Clinical variables and comorbidity, habits, and surgery-related variables were assessed by univariate and multivariate analyses to determine preoperative risk factors for clinical AL.

Results

The overall rate of clinical AL was 11.7% (18 of 154 patients), and 5 (27.8%) of 18 patients required revised laparotomy. Data from males were analyzed because AL occurred only in males. Univariate analysis of male patients (n = 100) significantly associated preoperative creatinine values (p = 0.03) and a history of ischemic heart disease (IHD) (p = 0.012) with AL. The frequency of AL tended to increase (p = 0.06) when patients had low AR (p = 0.06) and transanal drainage. Having AL significantly prolonged hospital stays compared with patients without leakage (36.2 vs. 11.1 days; p <  0.01). Multivariate analysis identified a history of IHD (odds ratio [OR], 4.73; 95% confidence interval [CI], 1.27–17.5; p = 0.025] as an independent risk factor for AL.

Conclusions

Male sex and a history of IHD are possible risk factors for AL after elective laparoscopic rectal cancer surgery.

Smoking and tumor obstruction are risk factors for anastomotic leakage after laparoscopic anterior resection during rectal cancer treatment

Objectives: To clarify the surgical outcomes and risk factors for anastomotic leakage (AL) following laparoscopic anterior resection (Lap-AR) for the treatment of rectal cancer. Methods: We retrospectively reviewed the records of 175 consecutive primary rectal cancer patients who had undergone Lap-AR at our institution between April 2012 and November 2015. Patient, tumor, and surgical variables were analyzed using univariate analyses. Results: Of 175 patients, 116 were men (66.3%). All four patients who had AL (2.3%) were men and current smokers with heavy smoking histories. In three of the AL cases, preoperative total colonoscopy was impossible owing to tumor obstruction, and the other case had concomitant obstructive colitis after oral bowel preparation. Univariate analysis identified tumor size, tumor obstruction, and smoking history as factors significantly associated with AL development. Conclusions: Tumor size, tumor obstruction, and smoking history were risk factors for AL following Lap-AR for the treatment of primary rectal cancer.

The triune of intestinal microbiome, genetics and inflammatory status and its impact on the healing of lower gastrointestinal anastomoses

Gastrointestinal resections are a common operation and most involve an anastomosis to rejoin the ends of the remaining bowel to restore gastrointestinal (GIT) continuity. While most joins heal uneventfully, in up to 26% of patients healing fails and an anastomotic leak (AL) develops. Despite advances in surgical technology and techniques, the rate of anastomotic leaks has not decreased over the last few decades raising the possibility that perhaps we do not yet fully understand the phenomenon of AL and are thus ill-equipped to prevent it. As in all complex conditions, it is necessary to isolate each different aspect of disease for interrogation of its specific role, but, as we hope to demonstrate in this article, it is a dangerous oversimplification to consider any single aspect as the full answer to the problem. Instead, consideration of important individual observations in parallel could illuminate the way forward towards a possibly simple solution amidst the complexity. This article details three aspects that we believe intertwine, and therefore should be considered together in wound healing within the GIT during postsurgical recovery: the microbiome, the host genetic make-up and their relationship to the perioperative inflammatory status. Each of these, alone or in combination, has been linked with various states of health and disease, and in combining these three aspects in the case of postoperative recovery from bowel resection, we may be nearer an answer to preventing anastomotic leaks than might have been thought just a few years ago.

Intraoperative colonic pulse oximetry in left-sided colorectal surgery: can it predict anastomotic leak?

BACKGROUND

An anastomotic leak is a fairly common and a potentially lethal complication in colorectal surgery. Objective methods to assess the viability and blood circulation of the anastomosis could help in preventing leaks. Intraoperative pulse oximetry is a cheap, easy to use, fast, and readily available method to assess tissue viability. Our aim was to study whether intraoperative pulse oximetry can predict the development of an anastomotic leak.

METHODS

The study was a prospective single-arm study conducted between the years 2005 and 2011 in Helsinki University Hospital. Patient material consisted of 422 patients undergoing elective left-sided colorectal surgery. The patients were operated by one of the three surgeons. All of the operations were partial or total resections of the left side of the colon with a colorectal anastomosis. The intraoperative colonic oxygen saturation was measured with pulse oximetry from the colonic wall, and the values were analyzed with respect to post-operative complications.

RESULTS

2.3 times more operated anastomotic leaks occurred when the colonic StO₂ was ≤ 90% (11/129 vs 11/293). The mean colonic StO₂ was 91.1 in patients who developed an operated anastomotic leak and 93.0 in patients who did not. With logistic regression analysis, the risk of operated anastomotic leak was 4.2 times higher with StO₂ values ≤ 90%.

CONCLUSIONS

Low intraoperative colonic StO₂ values are associated with the occurrence of anastomotic leak. Despite its handicaps, the method seems to be useful in assessing anastomotic viability.

Roles of Macrophage Subtypes in Bowel Anastomotic Healing and Anastomotic Leakage

Macrophages play an important role in host defense, in addition to the powerful ability to phagocytose pathogens or foreign matters. They fulfill a variety of roles in immune regulation, wound healing, and tissue homeostasis preservation. Macrophages are characterized by high heterogeneity, which can polarize into at least two major extremes, M1-type macrophages (classical activation) which are normally derived from monocytes and M2-type macrophages (alternative activation) which are mostly those tissue-resident macrophages. Based on the wound healing process in skin, the previous studies have documented how these different subtypes of macrophages participate in tissue repair and remodeling, while the mechanism of macrophages in bowel anastomotic healing has not yet been established. This review summarizes the currently available evidence regarding the different roles of polarized macrophages in the physiological course of anastomotic healing and their pathological roles in anastomotic leakage, the most dangerous complication after gastrointestinal surgery.

Role of Indocyanine Green in Fluorescence Imaging with Near-Infrared Light to Identify Sentinel Lymph Nodes, Lymphatic Vessels and Pathways Prior to Surgery - A Critical Evaluation of Options

Modern surgical strategies aim to reduce trauma by using functional imaging to improve surgical outcomes. This reviews considers and evaluates the importance of the fluorescent dye indocyanine green (ICG) to visualize lymph nodes, lymphatic pathways and vessels and tissue borders in an interdisciplinary setting. The work is based on a selective search of the literature in PubMed, Scopus, and Google Scholar and the authors' own clinical experience. Because of its simple, radiation-free and uncomplicated application, ICG has become an important clinical indicator in recent years. In oncologic surgery ICG is used extensively to identify sentinel lymph nodes with promising results. In some studies, the detection rates with ICG have been better than the rates obtained with established procedures. When ICG is used for visualization and the quantification of tissue perfusion, it can lead to fewer cases of anastomotic insufficiency or transplant necrosis. The use of ICG for the imaging of organ borders, flap plasty borders and postoperative vascularization has also been scientifically evaluated. Combining the easily applied ICG dye with technical options for intraoperative and interventional visualization has the potential to create new functional imaging procedures which, in future, could expand or even replace existing established surgical techniques, particularly the techniques used for sentinel lymph node and anastomosis imaging.

Intraoperative use of ICG fluorescence imaging to reduce the risk of anastomotic leakage in colorectal surgery: a systematic review and meta-analysis

BACKGROUND

Indocyanine green (ICG) fluorescence imaging has been proven to be an effective tool to assess anastomotic perfusion. The aim of this systematic review and meta-analysis was to evaluate its efficacy in reducing the anastomotic leakage (AL) rate after colorectal surgery.

METHODS

PubMed, Scopus, WOS, Google Scholar and Cochrane Library were searched up to January 2017 for studies comparing fluorescence imaging with standard care. ClinicalTrials.gov register was searched for ongoing trials. The primary outcome measure was AL rate with at least 1 month of follow-up. ROBINS-I tool was used for quality assessment. A meta-analysis with random-effects model was performed to calculate odds ratios (ORs) from the original data.

RESULTS

One thousand three hundred and two patients from 5 non-randomized studies were included. Fluorescence imaging significantly reduced the AL rate in patients undergoing surgery for colorectal cancer (OR 0.34; CI 0.16-0.74; p = 0.006). Low AL rates were shown in rectal cancer surgery (ICG 1.1% vs non-ICG 6.1%; p = 0.02). There was no significant decrease in the AL rate when colorectal procedures for benign and malignant disease were combined. To date, there are no published randomized control trials (RCTs) on this subject, though 3 ongoing RCTs were identified.

CONCLUSIONS

ICG fluorescence imaging seems to reduce AL rates following colorectal surgery for cancer. However, the inherent bias of the non-randomized studies included, and their differences in AL definition and diagnosis could have influenced results. Large well-designed RCTs are needed to provide evidence for its routine use in colorectal surgery.

Colon Perfusion Patterns During Colorectal Resection Using Visible Light Spectroscopy

BACKGROUND

The impact of blood supply to the anastomosis on development of anastomotic leakage is still a matter of debate. Considering that bowel perfusion may be affected by manipulation during surgery, perfusion assessment of the anastomosis alone may be of limited value. We propose perfusion assessment at different time points during surgery to explore the dynamics of bowel perfusion during colorectal resection and its impact on outcome.

METHODS

In this prospective cohort study, patients undergoing elective colorectal resection were eligible. Colon perfusion was evaluated using visible light spectroscopy. Main outcome was the difference in colon perfusion, quantified by measuring tissue oxygen saturation (StO₂) in the colonic serosa, before and after anastomosis during surgery.

RESULTS

We included 58 patients between July 2013 and November 2015. Colon perfusion increased by an average of 5.9% StO₂ during surgery (95% confidence interval 3.1, 8.8; P < 0.001). The number of patients with abnormal perfusion (defined as StO₂ < 65%) decreased from 50% at the beginning to 24% by the end of surgery. Six patients (10%) developed anastomotic leaks (AL), of which five patients had abnormal perfusion at the beginning of surgery, whereas four patients had normal StO₂ at the anastomosis.

CONCLUSION

Colon perfusion significantly increased during colorectal surgery. Considering that one quarter of patients had suboptimal anastomotic perfusion without developing AL, impaired blood flow at the anastomosis alone does not seem to be critical. Further investigations including more patients are necessary to evaluate the impact of perioperative parameters on colon perfusion, anastomotic healing and surgical outcome.

Low values of central venous oxygen saturation (ScvO2) during surgery and anastomotic leak of abdominal trauma patients

Background

There is a well known relationship between hypoperfusion and postoperative complications like anastomotic leak. No studies have been done addressing this relationship in the context of abdominal trauma surgery. Central venous oxygen saturation is an important hypoperfusion marker of potential use in abdominal trauma surgery for identifying the risk of anastomotic leak development. The purpose of this study was to identify the relationship between low values of central venous oxygen saturation and anastomotic leak of gastrointestinal sutures in the postoperative period in abdominal trauma surgery.

Methods

A cross-sectional prospective study was performed. Patients over 14 years old who required surgical gastrointestinal repair secondary to abdominal trauma were included. Anastomotic leak diagnosis was confirmed through clinical manifestations and diagnostic images or secondary surgery when needed. Central venous oxygen blood saturation was measured at the beginning of surgery through a central catheter. Demographic data, trauma mechanism, anatomic site of trauma, hemoglobin levels, abdominal trauma index, and comorbidities were assessed as secondary variables.

Results

Patients who developed anastomotic leak showed lower mean central venous oxygen saturation levels (60.0% ± 2.94%) than those who did not (69.89% ± 7.21%) (p = 0.010).

Conclusions

Central venous oxygen saturation <65% was associated with the development of gastrointestinal leak during postoperative time of patients who underwent surgery secondary to abdominal trauma.

Cyclooxygenase-2 Is Essential for Colorectal Anastomotic Healing

OBJECTIVE

To study the effects of COX-2 on colonic surgical wound healing.

BACKGROUND

Cyclooxygenase-2 (COX-2) is a key enzyme in gastrointestinal homeostasis. COX-2 inhibitors have been associated with colonic anastomotic leakage.

METHODS

Wildtype, COX-2 knockout and COX-2 heterozygous mice were subjected to a model of colonic anastomotic leakage, and were treated with vehicle, diclofenac, or prostaglandin E2 (PGE2), the most important COX-2 product in the intestine. We assessed anastomotic leakage, mortality, angiogenesis, and inflammation. Furthermore, we investigated the association between anastomotic leakage and a human polymorphism of the COX-2 gene resulting in low COX-2 levels.

RESULTS

Diclofenac, a nonsteroidal anti-inflammatory drug inhibiting COX-2, increased anastomotic leakage compared to vehicle-treated mice (100% vs 25%, respectively). Similarly, 92% of COX-2-deficient mice developed anastomotic leakage (P = 0.003) compared to WT. PGE2 partly rescued this severe phenotype because only 46% of PGE2-administered COX-2 knockout mice developed anastomotic leakage (P = 0.02). This may be related to decreased neovascularization, because decreased CD31 staining, indicating less blood vessels, was observed in COX-2 mice (2 vessels/mm vs 6 vessels/mm in controls (P = 0.03)). This effect could partly be reversed by administration of PGE2 to COX-2 mice. No significant differences in inflammation were found. PTGS2-765G>C polymorphism in humans, associated with reduced COX-2 expression, was associated with higher anastomotic leakage rates.

CONCLUSIONS

COX-2-induced PGE2 production is essential for intestinal wound healing after colonic surgery, possibly via its effects on angiogenesis. These data emphasize that COX-2 inhibitors should be avoided after colonic surgery, and administration of PGE2 might be favorable for a selection of patients.

Lack of evidence for tissue hypoxia as a contributing factor in anastomotic leak following colon anastomosis and segmental devascularization in rats

PURPOSE

Current surgical dogma dictates that tissue ischemia and hypoxia are major contributing factors in anastomotic leak despite scant evidence. The aim of this study was to determine if tissue hypoxia is a feature of anastomotic leakage in rats following colon resection and segmental devascularization.

METHODS

Rats were randomly assigned to undergo sham operation, segmental colon devascularization alone, colectomy alone, or segmental devascularization plus colectomy. Tissue hypoxia present at the colon anastomosis site across the various treatment groups was determined at sacrifice on postoperative day 6. Pimonidazole HCl was injected 30 min prior to sacrifice. Anastomotic tissues were examined and scored for healing versus leakage using an anastomotic healing score (AHS). Collagen content, hypoxia, enteric smooth muscle and periendothelial stromal patterning, and apoptosis were evaluated histologically.

RESULTS

No differences in tissue hypoxia were noted in the 16% of anastomotic tissues with poor healing compared to the remaining 84% of rats whose anastomoses healed well. No significant changes were found in cell death in the submucosa of any group. Consistent with previous findings, poor healing was associated with lower collagen content. Submucosal thickness correlated with increased arteriole diameter (R ² = 0.25, p < 0.005).

CONCLUSIONS

These results demonstrate that tissue hypoxia is not a distinctive feature of anastomotic tissues that fail to heal and leak, even when their blood supply is interrupted. These findings suggest that compensatory factors may mitigate the effects of ischemia and hypoxia during healing of anastomotic tissues and that the process of leakage involves factors beyond their acute effects.

Interpretative Guidelines and Possible Indications for Indocyanine Green Fluorescence Imaging in Robot-Assisted Sphincter-Saving Operations

BACKGROUND

Since the introduction of indocyanine green angiography more than 25 years ago, few studies have presented interpretative guidelines for indocyanine green fluorescent imaging.

OBJECTIVE

We aimed to provide interpretative guidelines for indocyanine green fluorescent imaging through quantitative analysis and to suggest possible indications for indocyanine green fluorescent imaging during robot-assisted sphincter-saving operations.

DESIGN

This is a retrospective observational study.

SETTINGS

This study was conducted at a single center.

PATIENTS

A cohort of 657 patients with rectal cancer who consecutively underwent curative robot-assisted sphincter-saving operations was enrolled between 2010 and 2016, including 310 patients with indocyanine green imaging (indocyanine green fluorescent imaging+ group) and 347 patients without indocyanine green imaging (indocyanine green fluorescent imaging- group).

MAIN OUTCOME MEASURES

We tried to quantitatively define the indocyanine green fluorescent imaging findings based on perfusion (mesocolic and colic) time and perfusion intensity (5 grades) to provide probable indications.

RESULTS

The anastomotic leakage rate was significantly lower in the indocyanine green fluorescent imaging+ group than in the indocyanine green fluorescent imaging- group (0.6% vs 5.2%) (OR, 0.123; 95% CI, 0.028-0.544; p = 0.006). Anastomotic stricture was closely correlated with anastomotic leakage (p = 0.002) and a short descending mesocolon (p = 0.003). Delayed perfusion (>60 s) and low perfusion intensity (1-2) were more frequently detected in patients with anastomotic stricture and marginal artery defects than in those without these factors (p ≤ 0.001). In addition, perfusion times greater than the mean were more frequently observed in patients aged >58 years, whereas low perfusion intensity was seen more in patients with short descending mesocolon and high ASA classes (≥3).

LIMITATIONS

The 300 patients in the indocyanine green fluorescent imaging- group underwent operations 3 years before indocyanine green fluorescent imaging.

CONCLUSIONS

Quantitative analysis of indocyanine green fluorescent imaging may help prevent anastomotic complications during robot-assisted sphincter-saving operations, and may be of particular value in high-class ASA patients, older patients, and patients with a short descending mesocolon.

ICG fluorescence imaging for quantitative evaluation of colonic perfusion in laparoscopic colorectal surgery

BACKGROUND

Fluorescence technology with indocyanine green (ICG) provides a real-time assessment of intestinal perfusion. However, a subjective evaluation of fluorescence intensity based on the surgeon's visual judgement is a major limitation. This study evaluated the quantitative assessment of ICG fluorescence imaging in determining the transection line of the proximal colon during laparoscopic colorectal surgery.

METHODS

This is a retrospective analysis of a prospectively maintained database of 112 patients who underwent laparoscopic surgery for left-sided colorectal cancers. After distal transection of the bowel, the specimen was extracted extracorporeally and then the proximal colon was divided within the well-perfused area based on the ICG fluorescence imaging. We evaluated whether quantitative assessment of intestinal perfusion by measuring ICG intensity could predict postoperative outcomes: F _max, T _max, T _1/2, and Slope were calculated.

RESULTS

Anastomotic leakage (AL) occurred in 5 cases (4.5%). Based on the fluorescence imaging, the surgical team opted for further proximal change of the transection line up to an "adequate" fluorescent portion in 18 cases (16.1%). Among the 18 patients, AL occurred in 4 patients (4/18: 22.2%), whereas it occurred in only 1 case (1/94: 1.0%) in the good perfusion patients who did not need proximal change of the transection line. The F _max of the AL group was less than 52.0 in all 5 cases (5/5), whereas that of the non-AL group was in only 8 cases (8/107): with an F _max cutoff value of 52.0, the sensitivity and specificity for the prediction of AL were 100 and 92.5%, respectively. Regarding postoperative bowel movement recovery, the T _max of the early flatus group or early defecation group was significantly lower than that of the late flatus group or late defecation group, respectively.

CONCLUSIONS

ICG fluorescence imaging is useful for assessing anastomotic perfusion in colorectal surgery, which can result in more precise operative decisions tailored for an individual patient.

Goal-directed fluid therapy for reducing risk of surgical site infections following abdominal surgery - A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Surgical site infections (SSIs) become a key indicator of quality of care. This meta-analysis aimed to determine the effect of goal-directed fluid therapy (GDFT) on the risk of SSIs after abdominal surgery.

METHODS

MEDLINE, Embase, CINAHL, Scopus, the Cochrane Controlled Trials Register, and Cochrane Database of Systematic Reviews were searched for randomized controlled trials (RCTs), from inception to May 2016 that compared the incidence of SSIs in abdominal surgical patients with or without GDFT treatment. . Data were pooled and risk ratio (RR) as well as weighted mean differences (WMD) with their 95% confidence intervals (CI) was calculated using either fixed or random effects models, depending on heterogeneity (I²).

RESULTS

A total of 29 eligible RCTs with 5317 patients were included in this analysis. GDFT significantly reduced the incidence of SSIs after abdominal surgery. The pooled RR was 0.74 (95% CI: 0.63 to 0.86) with low heterogeneity (I² = 4%). Length of hospital stay was significantly reduced in the GDFT group (WMD: -1.16 days, 95% CI: -1.92 to -0.40, p = 0.003; I² = 81%).

CONCLUSION

This systematic review suggests that perioperative GDFT is associated with a reduction in the incidence of SSIs after abdominal surgery.

Emerging Trends in the Etiology, Prevention, and Treatment of Gastrointestinal Anastomotic Leakage

Anastomotic leaks represent one of the most alarming complications following any gastrointestinal anastomosis due to the substantial effects on post-operative morbidity and mortality of the patient with long-lasting effects on the functional and oncologic outcomes. There is a lack of consensus related to the definition of an anastomotic leak, with a variety of options for prevention and management. A number of patient-related and technical risk factors have been found to be associated with the development of an anastomotic leak and have inspired the development of various preventative measures and technologies. The International Multispecialty Anastomotic Leak Global Improvement Exchange group was convened to establish a consensus on the definition of an anastomotic leak as well as to discuss the various diagnostic, preventative, and management measures currently available.

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.

Preoperative, intraoperative and postoperative risk factors for anastomotic leakage after laparoscopic low anterior resection with double stapling technique anastomosis

Anastomotic leakage (AL) is one of the most devastating complications after rectal cancer surgery. The double stapling technique has greatly facilitated intestinal reconstruction especially for anastomosis after low anterior resection (LAR). Risk factor analyses for AL after open LAR have been widely reported. However, a few studies have analyzed the risk factors for AL after laparoscopic LAR. Laparoscopic rectal surgery provides an excellent operative field in a narrow pelvic space, and enables total mesorectal excision surgery and preservation of the autonomic nervous system with greater precision. However, rectal transection using a laparoscopic linear stapler is relatively difficult compared with open surgery because of the width and limited performance of the linear stapler. Moreover, laparoscopic LAR exhibits a different postoperative course compared with open LAR, which suggests that the risk factors for AL after laparoscopic LAR may also differ from those after open LAR. In this review, we will discuss the risk factors for AL after laparoscopic LAR.