Impact of intraoperative microperfusion assessment with Pinpoint Perfusion Imaging on surgical management of laparoscopic low rectal and anorectal anastomoses

Quantification of indocyanine-green-enhanced fluorescence with spectrophotometry (O2C®) in low anterior rectal resection: A prospective study

INTRODUCTION

Despite spectacular visuals and the seemingly convincing rationale of using indocyanine-green-enhanced fluorescence in assessing bowel perfusion during colorectal resections, a lingering sense of subjectivity remains in the challenge of quantifying this fluorescence. This prospective study analyzed the application of O2C® spectrophotometry to quantify zones of fluorescence on the large bowel during low anterior resection.

MATERIALS AND METHODS

Patients receiving a low anterior resection for cancer of the mid- and lower rectum were enrolled in this observational prospective study between February 2020 and December 2022. O2C® blood-flow measurement was performed at three different zones of fluorescence intensity (optimal [O], sufficient [S], and absent [A]), visualized at the designated and already skeletonized site of colon transection. The primary end point was to assess whether the O2C® flow value exceeds 164 arbitrary units (AU) at the zone of optimal fluorescence. The secondary objective was to assess whether there were statistically significant differences in flow parameters between the three zones, thus confirming reproducibility of measurements.

RESULTS

A total of 40 patients were enrolled in this study. Of these, 38 patients remained for statistical analysis with regard to O2C® measurement of the fluorescence zones. The O2C® flow parameter measured at the zone of optimal fluorescence was greater than 164 AU in all cases (100%, p < 0.0001). There were statistically significant differences in flow parameters measured at the three different zones of fluorescence (O-S: p < 0.0001; O-A: p < 0.0001; S-A: p = 0.0023).

CONCLUSION

This study proves the feasibility and reproducibility of quantifying zones of indocyanine green (ICG)-enhanced fluorescence on the bowel. All O2C® flow measurements that were collected at the zone of optimal fluorescence exceeded 164 AU, thereby adding more evidence to this value as a suggested cut-off parameter in terms of bowel perfusion.

Quadruple Assessment of Colorectal Anastomosis after Laparoscopic Rectal Resection: A Retrospective Analysis of a Propensity-Matched Cohort

Background: Anastomotic leakage (AL) is one of the most feared complications in colorectal surgery, with an incidence of 12-39% and associated risk of mortality of 2-24%. The causes of AL and the ways to prevent it are currently under investigation. This study aims to verify if a quadruple assessment of colorectal anastomosis could reduce AL incidence. Methods: A retrospective analysis of prospectively collected data on rectal cancer surgery performed from January 2015 to December 2017 and from January 2021 to December 2023 at a tertiary referral cancer centre was performed. Demographics, clinicopathological features, short-term outcomes, recurrences, and survival were investigated. Results: A total of 293 patients were enrolled. AL incidence was lower in the quadruple assessment group than in the control group, reaching a statistically significant result (7.7% vs. 16%; p = 0.001). This result was also confirmed after a propensity score match analysis (PSM), in which the AL rate was lower in the quadruple assessment group (5.4% vs. 12.3%; p = 0.01). Conclusions: This study shows how the systematic implementation of a quadruple assessment when performing a colorectal anastomosis could increase awareness on anastomotic success and reduce the incidence of AL.

Usefulness of fluorescence imaging with indocyanine green for evaluation of bowel perfusion in the urgency setting: a systematic review and meta-analysis

INTRODUCTION

Fluorescence imaging with indocyanine green (ICG) has been extensively utilized to assess bowel perfusion in oncologic surgery. In the emergency setting, there are many situations in which bowel perfusion assessment is required. Large prospective studies or RCTs evaluating feasibility, safety and utility of ICG in the emergency setting are lacking. The primary aim is to assess the usefulness of ICG for evaluation of bowel perfusion in the emergency setting.

MATERIALS AND METHODS

The manuscript was drafted following the recommendations of Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA). A systematic literature search was carried out through Pubmed, Scopus, and the ISI Web of Science. Assessment of included study using the methodological index for nonrandomized studies (MINORS) was calculated. The meta-analysis was carried out in line with recommendations from the Cochrane Collaboration and Meta-analysis of Observational Studies in Epidemiology guidelines, and the Mantel-Haenszel random effects model was used to calculate effect sizes.

RESULTS

10 093 papers were identified. Eighty-four were reviewed in full-text, and 78 were excluded: 64 were case reports; 10 were reviews without original data; 2 were letters to the editor; and 2 contained unextractable data. Finally, six studies 22-27 were available for quality assessment and quantitative synthesis. The probability of reoperation using ICG fluorescence angiography resulted similar to the traditional assessment of bowel perfusion with a RD was -0.04 (95% CI: -0.147 to 0.060). The results were statistically significant P =0.029, although the heterogeneity was not negligible with a 59.9% of the I2 index. No small study effect or publication bias were found.

CONCLUSIONS

This first metanalysis on the use of IGC fluorescence for ischemic bowel disease showed that this methodology is a safe and feasible tool in the assessment of bowel perfusion in the emergency setting. This topic should be further investigated in high-quality studies.

Real-time quantification of bowel perfusion using Laparoscopic Laser Speckle Contrast Imaging (LSCI) in a porcine model

BACKGROUND/PURPOSE

Real-time quantification of tissue perfusion can improve intraoperative surgical decision making. Here we demonstrate the utility of Laser Speckle Contrast Imaging as an intra-operative tool that quantifies real-time regional differences in intestinal perfusion and distinguishes ischemic changes resulting from arterial/venous obstruction.

METHODS

Porcine models (n = 3) consisted of selectively devascularized small bowel loops that were used to measure the perfusion responses under conditions of control/no vascular occlusion, arterial inflow occlusion, and venous outflow occlusion using laser speckle imaging and indocyanine green fluoroscopy. Laser Speckle was also used to assess perfusion differences between small bowel antimesenteric-antimesenteric and mesenteric-mesenteric anastomoses. Perfusion quantification was measured in relative perfusion units calculated from the laser speckle perfusion heatmap.

RESULTS

Laser Speckle distinguished between visually identified perfused, watershed, and ischemic intestinal segments with both color heatmap and quantification (p < .00001). It detected a continuous gradient of relative intestinal perfusion as a function of distance from the stapled ischemic bowel edge. Strong positive linear correlation between relative perfusion units and changes in mean arterial pressure resulting from both arterial (R2 = .96/.79) and venous pressure changes (R2 = .86/.96) was observed. Furthermore, Laser Speckle showed that the antimesenteric anastomosis had a higher perfusion than mesenteric anastomosis (p < 0.01).

CONCLUSIONS

Laser Speckle Contrast Imaging provides objective, quantifiable tissue perfusion information in both color heatmap and relative numerical units. Laser Speckle can detect spatial/temporal differences in perfusion between antimesenteric and mesenteric borders of a bowel segment and precisely detect perfusion changes induced by progressive arterial/venous occlusions in real-time.

Intraoperative bowel perfusion assessment methods and their effects on anastomotic leak rates: meta-analysis

BACKGROUND

Anastomotic leak is one of the most feared complications of colorectal surgery, and probably linked to poor blood supply to the anastomotic site. Several technologies have been described for intraoperative assessment of bowel perfusion. This systematic review and meta-analysis aimed to evaluate the most frequently used bowel perfusion assessment modalities in elective colorectal procedures, and to assess their associated risk of anastomotic leak. Technologies included indocyanine green fluorescence angiography, diffuse reflectance spectroscopy, laser speckle contrast imaging, and hyperspectral imaging.

METHODS

The review was preregistered with PROSPERO (CRD42021297299). A comprehensive literature search was performed using Embase, MEDLINE, Cochrane Library, Scopus, and Web of Science. The final search was undertaken on 29 July 2022. Data were extracted by two reviewers and the MINORS criteria were applied to assess the risk of bias.

RESULTS

Some 66 eligible studies involving 11 560 participants were included. Indocyanine green fluorescence angiography was most used with 10 789 participants, followed by diffuse reflectance spectroscopy with 321, hyperspectral imaging with 265, and laser speckle contrast imaging with 185. In the meta-analysis, the total pooled effect of an intervention on anastomotic leak was 0.05 (95 per cent c.i. 0.04 to 0.07) in comparison with 0.10 (0.08 to 0.12) without. Use of indocyanine green fluorescence angiography, hyperspectral imaging, or laser speckle contrast imaging was associated with a significant reduction in anastomotic leak.

CONCLUSION

Bowel perfusion assessment reduced the incidence of anastomotic leak, with intraoperative indocyanine green fluorescence angiography, hyperspectral imaging, and laser speckle contrast imaging all demonstrating comparable results.

Indocyanine green angiography for lower incidence of anastomotic leakage after transanal total mesorectal excision: a propensity score-matched cohort study

Background

Anastomotic leakage (AL) is the most serious complication that can arise during colorectal surgery. Indocyanine green (ICG) angiography offers an intraoperative assessment of colonic vascular perfusion in real time. We aimed to assess ICG's effects on the AL rate in patients who have undergone transanal total mesorectal excision (TaTME) for rectal cancer.

Methods

This retrospective cohort study was conducted at our center from October 2018 to March 2022 to analyze the clinical data of patients with rectal cancer who have undergone TaTME after propensity score matching (PSM). The primary outcome was the proximal colonic transection line modification and clinical AL rate.

Results

A total of 143 patients in the non-ICG group and 143 patients in the ICG group were included after PSM. The proximal colonic transection line of seven patients in the non-ICG group was modified, while 18 were in the ICG group (4.9% vs. 12.5%, p = 0.023). Twenty-three patients (16.1%) in the non-ICG group and five patients (3.5%) in the ICG group were diagnosed with AL (p < 0.001). The ICG group had a less hospital readmission rate than the non-ICG group (0.7% vs. 7.7%, p = 0.003). The between-group differences in basic line and other outcomes were not significant.

Conclusions

ICG angiography is a safe and feasible method to help surgeons identify potentially poor colonic vascular perfusion and modify the proximal colonic transection line, resulting in a significant reduction in AL and hospital readmission rates.

Anastomotic perfusion assessment with indocyanine green in robot-assisted low-anterior resection, a multicenter study of interobserver variation

BACKGROUND

Securing sufficient blood perfusion to the anastomotic area after low-anterior resection is a crucial factor in preventing anastomotic leakage (AL). Intra-operative indocyanine green fluorescent imaging (ICG-FI) has been suggested as a tool to assess perfusion. However, knowledge of inter-observer variation among surgeons in the interpretation of ICG-FI is sparse. Our primary objective was to evaluate inter-observer variation among surgeons in the interpretation of bowel blood-perfusion assessed visually by ICG-FI. Our secondary objective was to compare the results both from the visual assessment of ICG and from computer-based quantitative analyses of ICG-FI between patients with and without the development of AL.

METHOD

A multicenter study, including patients undergoing robot-assisted low anterior resection with stapled anastomosis. ICG-FI was evaluated visually by the surgeon intra-operatively. Postoperatively, recorded videos were anonymized and exchanged between centers for inter-observer evaluation. Time to visibility (TTV), time to maximum visibility (TMV), and time to wash-out (TWO) were visually assessed. In addition, the ICG-FI video-recordings were analyzed using validated pixel analysis software to quantify blood perfusion.

RESULTS

Fifty-five patients were included, and five developed clinical AL. Bland-Altman plots (BA plots) demonstrated wide inter-observer variation for visually assessed fluorescence on all parameters (TTV, TMV, and TWO). Comparing leak-group with no-leak group, we found no significant differences for TTV: Hazard Ratio; HR = 0.82 (CI 0.32; 2.08), TMV: HR = 0.62 (CI 0.24; 1.59), or TWO: HR = 1.11 (CI 0.40; 3.11). In the quantitative pixel analysis, a lower slope of the fluorescence time-curve was found in patients with a subsequent leak: median 0.08 (0.07;0.10) compared with non-leak patients: median 0.13 (0.10;0.17) (p = 0.04).

CONCLUSION

The surgeon's visual assessment of the ICG-FI demonstrated wide inter-observer variation, there were no differences between patients with and without AL. However, quantitative pixel analysis showed a significant difference between groups.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04766060.

European Association for Endoscopic Surgery (EAES) consensus on Indocyanine Green (ICG) fluorescence-guided surgery

BACKGROUND

In recent years, the use of Indocyanine Green (ICG) fluorescence-guided surgery during open and laparoscopic procedures has exponentially expanded across various clinical settings. The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on this topic with the aim of creating evidence-based statements and recommendations for the surgical community.

METHODS

An expert panel of surgeons has been selected and invited to participate to this project. Systematic reviews of the PubMed, Embase and Cochrane libraries were performed to identify evidence on potential benefits of ICG fluorescence-guided surgery on clinical practice and patient outcomes. Statements and recommendations were prepared and unanimously agreed by the panel; they were then submitted to all EAES members through a two-rounds online survey and results presented at the EAES annual congress, Barcelona, November 2021.

RESULTS

A total of 18,273 abstracts were screened with 117 articles included. 22 statements and 16 recommendations were generated and approved. In some areas, such as the use of ICG fluorescence-guided surgery during laparoscopic cholecystectomy, the perfusion assessment in colorectal surgery and the search for the sentinel lymph nodes in gynaecological malignancies, the large number of evidences in literature has allowed us to strongly recommend the use of ICG for a better anatomical definition and a reduction in post-operative complications.

CONCLUSIONS

Overall, from the systematic literature review performed by the experts panel and the survey extended to all EAES members, ICG fluorescence-guided surgery could be considered a safe and effective technology. Future robust clinical research is required to specifically validate multiple organ-specific applications and the potential benefits of this technique on clinical outcomes.

Meta analysis of indocyanine green fluorescence in patients undergoing laparoscopic colorectal cancer surgery

This meta-analysis intended to systematically evaluate the clinical implications of indocyanine green fluorescence (ICG) in patients undergoing laparoscopic colorectal surgery. PubMed, MEDLINE, Cochrane Library, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Medical Information System and China Biomedical Database were synthetically searched for studies published from inception to April 14, 2022. The randomized controlled trials comparing ICG-use with controls were selected. The incidence of anastomotic leakage (AL), lymph node detection, operation duration, intraoperative bleeding, postoperative morbidity, and hospitalization time were evaluated in summary analysis, and calculated the corresponding 95% confidence intervals (CI). Subsequently, in addition to subgroup analyses, studies for heterogeneity, sensitivity, and publication bias were carried out. Consequently, 3453 patients in the enrolled 15 studies were included; 1616 patients were allocated to the experimental group, and 1837 patients were assigned to the control group. The ICG group had a significantly decreased risk of AL (RR: 0.50, 95% CI: 0.37-0.67) and shorter hospitalization time (SMD: -0.31, 95% CI: -0.54-0.08) compared to the control group. Meanwhile, the ICG showed clearly better lymph node detection (SMD: 0.19, 95% CI: 0.02-0.36). However, when the content of operation duration (SMD: -0.07, 95% CI: -0.30-0.15) and intraoperative bleeding (SMD: -0.16, 95% CI: -0.35-0.04) were compared, no statistical significance was found. Furthermore, the pooled analysis of postoperative morbidity was not statistically significant (RR:0.79, 95% CI: 0.58-1.08). The results of the subgroup analysis of AL indicated that there may be regional variations in AL (RR: 0.50, 95% CI: 0.37-0.67) but not in postoperative morbidity (RR: 0.79, 95% CI: 0.58-1.08). In conclusion, the application of ICG in laparoscopic colorectal surgery can effectively reduce the AL, lymph node detection, and hospitalization time. However, more multicenter large-sample randomized controlled trials are required to further confirm its advantages. The meta-analysis was registered in PROSPERO (no. CRD42022288054).

Indocyanine green (ICG) fluorescence guide for the use and indications in general surgery: recommendations based on the descriptive review of the literature and the analysis of experience

Indocyanine Green is a fluorescent substance visible in near-infrared light. It is useful for the identification of anatomical structures (biliary tract, ureters, parathyroid, thoracic duct), the tissues vascularization (anastomosis in colorectal, esophageal, gastric, bariatric surgery, for plasties and flaps in abdominal wall surgery, liver resection, in strangulated hernias and in intestinal ischemia), for tumor identification (liver, pancreas, adrenal glands, implants of peritoneal carcinomatosis, retroperitoneal tumors and lymphomas) and sentinel node identification and lymphatic mapping in malignant tumors (stomach, breast, colon, rectum, esophagus and skin cancer). The evidence is very encouraging, although standardization of its use and randomized studies with higher number of patients are required to obtain definitive conclusions on its use in general surgery. The aim of this literature review is to provide a guide for the use of ICG fluorescence in general surgery procedures.

Does the level of inferior mesenteric artery ligation affect short-term and long-term outcomes of patients with sigmoid colon cancer or rectal cancer? A single-center retrospective study

Background

For sigmoid colon or rectal cancer, a definite consensus regarding the optimal level ligating the inferior mesenteric artery (IMA) has not been reached. We performed this study to determine whether the ligation level significantly affected short-term and long-term outcomes of patients with sigmoid colon or rectal cancer after curative laparoscopic surgery.

Methods

Medical records of patients with sigmoid colon or rectal cancer who had undergone curative laparoscopic surgery between January 2008 and December 2014 at the Department of Gastrointestinal Surgery, Guangdong Provincial Hospital of Traditional Chinese Medicine were reviewed. Then, the high tie group (HTG) was compared with the low tie group (LTG) in terms of short-term and long-term outcomes.

Results

Five-hundred ninety patients were included. No significant differences between two groups regarding baseline characteristics existed. HTG had a significantly higher risk of anastomotic fistula than LTG (21/283 vs 11/307, P = 0.040). Additionally, high ligation was proven by multivariate logistic regression analysis to be an independent factor for anastomotic fistula (P = 0.038, OR = 2.232, 95% CI: 1.047–4.758). Furthermore, LT resulted in better preserved urinary function. However, LTG was not significantly different from HTG regarding operative time (P = 0.075), blood transfusion (P = 1.000), estimated blood loss (P = 0.239), 30-day mortality (P = 1.000), ICU stay (P = 0.674), postoperative hospital stay (days) (P = 0.636), bowel obstruction (P = 0.659), ileus (P = 0.637), surgical site infection (SSI) (P = 0.121), number of retrieved lymph nodes (P = 0.501), and number of metastatic lymph nodes (P = 0.131). Subsequently, it was revealed that level of IMA ligation did not significantly influence overall survival (OS) (P = 0.474) and relapse-free survival (RFS) (P = 0.722). Additionally, it was revealed that ligation level did not significantly affect OS (P = 0.460) and RFS (P = 0.979) of patients with stage 1 cancer, which was also observed among patients with stage 2 or stage 3 cancer. Ultimately, ligation level was not an independent predictive factor for either OS or RFS.

Conclusions

HT resulted in a significantly higher incidence of anastomotic fistula and worse preservation of urinary function. Level of IMA ligation did not significantly affect long-term outcomes of patients with sigmoid colon or rectal cancer after curative laparoscopic surgery.

Indocyanine green (ICG) fluorescence imaging for prevention of anastomotic leak in totally minimally invasive Ivor Lewis esophagectomy: a systematic review and meta-analysis

BACKGROUND

Indocyanine green (ICG) fluorescence imaging is an emerging technology that might help decreasing anastomotic leakage (AL) rates. The aim of this study was to determine the usefulness of ICG fluorescence imaging for the prevention of AL after minimally invasive esophagectomy with intrathoracic anastomosis.

METHODS

A systematic literature review of the MEDLINE and Cochrane databases was performed to identify all articles on totally minimally invasive Ivor Lewis esophagectomy. Studies were then divided into two groups based on the use or not of ICG for perfusion assessment. Primary outcome was anastomotic leak. Secondary outcomes included operative time, ICG-related adverse reactions, and mortality rate. A meta-analysis was conducted to estimate the overall weighted proportion and its 95% confidence interval (CI) for main outcomes.

RESULTS

A total of 3,171 patients were included for analysis: 381 (12%) with intraoperative ICG fluorescence imaging and 2,790 (88%) without ICG. Mean patients' age and proportion of males were similar between groups. Mean operative time was also similar between both groups (ICG: 354.8 vs. No-ICG: 354.1 minutes, P = 0.52). Mean ICG dose was 12 mg (5-21 mg). No ICG-related adverse reactions were reported. AL rate was 9% (95% CI, 5-17%) and 9% (95% CI, 7-12%) in the ICG and No-ICG groups, respectively. The risk of AL was similar between groups (odds ratio 0.85, 95% CI 0.53-1.28, P = 0.45). Mortality was 3% (95% CI, 1-9%) in patients with ICG and 2% (95% CI, 2-3%) in those without ICG. Median length of hospital stay was also similar between groups (ICG: 13.6 vs. No-ICG: 11.2 days, P = 0.29).

CONCLUSION

The use of ICG fluorescence imaging for perfusion assessment does not seem to reduce AL rates in patients undergoing minimally invasive esophagectomy with intrathoracic anastomosis.

Indocyanine Green Near-Infrared Fluoroangiography Is a Useful Tool in Reducing the Risk of Anastomotic Leakage Following Left Colectomy

Purpose

To evaluate whether visualization of the colon perfusion with indocyanine green near-infrared fluoroangiography (ICG-NIFA) reduces the rate of anastomotic leakage (AL) after colorectal anastomosis.

Methods

Patients who underwent elective left colectomy, including all procedures involving the sigmoid colon and the rectum with a colorectal or coloanal anastomosis, were retrospectively analyzed for their demographics, operative details, and the rate of AL. Univariate and multivariate analyses were used to compare patients with and without ICG-NIFA-based evaluation.

Results

Overall, our study included 132 colorectal resections [70 sigmoid resections and 62 total mesorectal excisions (TMEs)], of which 70 (53%) were performed with and 62 (47%) without ICG-NIFA. Patients' characteristics were similar between both the groups. The majority of the procedures [91 (69%)] were performed by certified colorectal surgeons, while 41 (31%) operations were supervised teaching procedures. In the ICG-NIFA group, bowel perfusion could be visualized by fluorescence (dye) in all 70 cases, and no adverse effects related to the fluorescent dye were observed. Following ICG-NIFA, the transection line was changed in 9 (12.9%) cases. Overall, 10 (7.6%) patients developed AL, 1 (1.4%) in the ICG-NIFA group and 9 (14.5%) in the no-ICG-NIFA group (p = 0.006). The multivariate analysis revealed ICG-NIFA as an independent factor to reduce AL.

Conclusion

These results suggest that ICG-NIFA might be a valuable tool to reduce the rate of AL in sigmoid and rectal resections in an educational setting.

Immunofluorescence in Robotic Colon and Rectal Surgery

The indocyanine green fluorescence imaging system is a surgical tool with increasing applications in colon and rectal surgery that has received growing acceptance in various surgical disciplines as a potentially valid method to enhance surgical field visualization, improve lymph node retrieval, and decrease anastomotic leak. Small noncomparative prospective trials have shown that intraoperative fluorescence imaging is a safe and feasible method to assess anastomotic perfusion and that its use may impact anastomotic leak rates. However, larger prospective and randomized studies are required to validate its role and impact in colorectal surgery. The purpose of this article is to review the current status of the use of immunofluorescence in colon and rectal surgery, as well as new applications in robotic colon and rectal resections.

Effect of indocyanine green fluorescence angiography on preventing anastomotic leakage after colorectal surgery: a meta-analysis

Anastomotic leakage (AL) is a serious but not uncommon complication after colorectal surgery. We conducted this study to evaluate the effect of routine indocyanine green fluorescence angiography (ICG-FA) on reducing the AL rate after colorectal surgery. We identified all research articles about colorectal surgery using ICG-FA, published in the PubMed, EMBASE, and Cochrane Library databases from the date of database establishment to May 2020. Revman 5.3 was used for statistical analysis. We analyzed 22 controlled studies and 7 non-controlled studies on ICG-FA, including 6312 patients. The controlled studies included 2354 patients in the ICG group and 3522 patients in the non-ICG group. Meta-analysis showed that ICG-FA reduced the AL rate after colorectal surgery significantly (RR = 0.39; 95% CI 0.30-0.50; P < 0.00001). However, patients whose resection line was changed based on the fluorescence angiography had a higher AL rate than those whose resection line was not changed (OR = 5.37; 95% CI 2.67-10.81; P < 0.00001). The overall complication rate, severe complication rate, and reoperation rate in the ICG group were significantly lower than those in the non-ICG group (RR = 0.79, 95% CI 0.67-0.92, P = 0.002; RR = 0.67, 95% CI 0.47-0.96, P = 0.03; RR = 0.53, 95% CI 0.29-0.96, P = 0.04, respectively), whereas the postoperative ileus rate was significantly higher in the ICG group than in the non-ICG group (RR = 1.65; 95% CI 1.09-2.50; P = 0.02), especially in Western countries (RR = 1.6; 95% CI 1.04-2.47; P = 0.03).ICG-FA may reduce the AL rate after colorectal surgery, but ICG-FA group patients with transection line change for insufficient blood perfusion to the anastomotic stoma after evaluation had a higher AL rate than those without transection line change. Therefore, ICG-FA can help to identify patients at high risk of AL and intercept its occurrence. Moreover, ICG-FA may reduce the overall complication rate, severe complication rate, and reoperation rate, but induce postoperative ileus. High-quality randomized-controlled trials with a placebo control are needed to further evaluate the effectiveness and safety of ICG-FA.

Intraoperative fluorescence angiography and risk factors of anastomotic leakage in mini-invasive low rectal resections

BACKGROUND

One of the prerequisites for proper healing of the anastomosis after a colorectal resection is adequate blood supply to the connected intestinal segments. It has been proposed that adequate visualization of the blood flow using indocyanine green (ICG) could lead to the reduction in the incidence of anastomotic leakage (AL). The aim of this study was to assess the effectiveness of intraoperative fluorescence angiography (FA) in decreasing the incidence of AL after minimally invasive low anterior resection (LAR) with total mesorectal excision (TME) in rectal cancer patients and to determine predictors of anastomotic leak.

METHODS

From August 2015 to January 2019, data from 100 patients who underwent mini-invasive TME for rectal cancer using FA with indocyanine green (ICG) were prospectively collected and analyzed. They were compared with retrospectively analyzed data from a historical control group operated by one team of surgeons before the introduction of FA from November 2012 to August 2015 (100 patients). All patients from both groups were operated sequentially in one oncological center in Nový Jičín.

RESULTS

The incidence of AL was significantly lower in the ICG group (19% vs. 9%, p = 0.042, χ2 test). In fifteen patients in the ICG group (15%), the resection line was moved due to insufficient perfusion. Using Pearson's χ2 test, diabetes (p = 0.036) and application of a transanal drain (NoCoil) (p = 0.032) were identified as other risk factors (RFs) for AL.

CONCLUSION

The use of ICG to visualize tissue perfusion in low rectal resections for cancer can lead to a reduction of AL.

Perfusion Assessment in Left-Sided/Low Anterior Resection (PILLAR III): A Randomized, Controlled, Parallel, Multicenter Study Assessing Perfusion Outcomes With PINPOINT Near-Infrared Fluorescence Imaging in Low Anterior Resection

BACKGROUND

Indocyanine green fluoroscopy has been shown to improve anastomotic leak rates in early phase trials.

OBJECTIVE

We hypothesized that the use of fluoroscopy to ensure anastomotic perfusion may decrease anastomotic leak after low anterior resection.

DESIGN

We performed a 1:1 randomized controlled parallel study. Recruitment of 450 to 1000 patients was planned over 2 years.

SETTINGS

This was a multicenter trial.

PATIENTS

Included patients were those undergoing resection defined as anastomosis within 10 cm of the anal verge.

INTERVENTION

Patients underwent standard evaluation of tissue perfusion versus standard in conjunction with perfusion evaluation using indocyanine green fluoroscopy.

MAIN OUTCOME MEASURES

Primary outcome was anastomotic leak, with secondary outcomes of perfusion assessment and the rate of postoperative abscess requiring intervention.

RESULTS

This study was concluded early because of decreasing accrual rates. A total of 25 centers recruited 347 patients, of whom 178 were randomly assigned to perfusion and 169 to standard. The groups had comparable tumor-specific and patient-specific demographics. Neoadjuvant chemoradiation was performed in 63.5% of perfusion and 65.7% of standard (p > 0.05). Mean level of anastomosis was 5.2 ± 3.1 cm in perfusion compared with 5.2 ± 3.3 cm in standard (p > 0.05). Sufficient visualization of perfusion was reported in 95.4% of patients in the perfusion group. Postoperative abscess requiring surgical management was reported in 5.7% of perfusion and 4.2% of standard (p = 0.75). Anastomotic leak was reported in 9.0% of perfusion compared with 9.6% of standard (p = 0.37). On multivariate regression analysis, there was no difference in anastomotic leak rates between perfusion and standard (OR = 0.845 (95% CI, 0.375-1.905); p = 0.34).

LIMITATIONS

The predetermined sample size to adequately reduce the risk of type II error was not achieved.

CONCLUSIONS

Successful visualization of perfusion can be achieved with indocyanine green fluoroscopy. However, no difference in anastomotic leak rates was observed between patients who underwent perfusion assessment versus standard surgical technique. In experienced hands, the addition of routine indocyanine green fluoroscopy to standard practice adds no evident clinical benefit. See Video Abstract at http://links.lww.com/DCR/B560.

VALORACIN DE LA IRRIGACIN DE LADO IZQUIERDO/RESECCIN ANTERIOR BAJA PILAR III UN ESTUDIO ALEATORIZADO, CONTROLADO, PARALELO Y MULTICNTRICO QUE EVALA LOS RESULTADOS DE LA IRRIGACIN CON PINPOINT IMGENES DE FLUORESCENCIA CERCANA AL INFRARROJO EN LA RESECCIN ANTERIOR BAJA

ANTECEDENTES:Se ha demostrado que la fluoroscopia con verde de indocianina mejora las tasas de fuga anastomótica en ensayos en fases iniciales.OBJETIVO:Nuestra hipótesis es que la utilización de fluoroscopia para asegurar la irrigación anastomótica puede disminuir la fuga anastomótica luego de una resección anterior baja.DISEÑO:Realizamos un estudio paralelo, controlado, aleatorizado 1:1. Se planificó el reclutamiento de 450-1000 pacientes durante 2 años.AMBITO:Multicéntrico.PACIENTES:Pacientes sometidos a resección definida como una anastomosis dentro de los 10cm del margen anal.INTERVENCIÓN:Pacientes que se sometieron a la evaluación estándar de la irrigación tisular contra la estándar en conjunto con la valoración de la irrigación mediante fluoroscopia con verde indocianina.PRINCIPALES VARIABLES EVALUADAS:El principal resultado fue la fuga anastomótica, y los resultados secundarios fueron la evaluación de la perfusión y la tasa de absceso posoperatorio que requirió intervención.RESULTADOS:Este estudio se cerró anticipadamente debido a la disminución de las tasas de acumulación. Un total de 25 centros reclutaron a 347 pacientes, de los cuales 178 fueron, de manera aleatoria, asignados a perfusión y 169 a estándar. Los grupos tenían datos demográficos específicos del tumor y del paciente similares. Recibieron quimio-radioterapia neoadyuvante el 63,5% de la perfusión y el 65,7% del estándar (p> 0,05). La anastomosis estuvo en un nivel promedio de 5,2 + 3,1 cm en perfusión en comparación con 5,2 + 3,3 cm en estándar (p> 0,05). Se reportó una visualización suficiente de la perfusión en el 95,4% de los pacientes del grupo de perfusión. El absceso posoperatorio que requirió tratamiento quirúrgico fue de 5,7% de los perfusion y en el 4,2% del estándar (p = 0,75). Se informó fuga anastomótica en el 9,0% de la perfusión en comparación con el 9,6% del estándar (p = 0,37). En el análisis de regresión multivariante, no hubo diferencias en las tasas de fuga anastomótica entre la perfusión y el estándar (OR 0,845; IC del 95% (0,375; 1,905); p = 0,34).LIMITACIONES:No se logró el tamaño de muestra predeterminado para reducir satisfactoriamente el riesgo de error tipo II.CONCLUSIÓN:Se puede obtener una visualización adecuada de la perfusión con ICG-F. Sin embargo, no se observaron diferencias en las tasas de fuga anastomótica entre los pacientes que se sometieron a evaluación de la perfusión versus la técnica quirúrgica estándar. En manos expertas, agregar ICG-F a la rutina de la práctica estándar no agrega ningún beneficio clínico evidente. Consulte Video Resumen en http://links.lww.com/DCR/B560. (Traducción-Dr Juan Antonio Villanueva-Herrero).

Optimization of indocyanine green angiography for colon perfusion during laparoscopic colorectal surgery

AIM

This study aims to evaluate the extrinsic effects of conditional factors affecting quantitative parameters and to establish the optimization of indocyanine green (ICG) angiography using in vitro experiments and a prospective observational study.

METHOD

In vitro experiments were performed to evaluate the correlation between conditional factors such as camera distance, surrounding lighting, fluorescence emission sources and ICG doses. The fluorescence intensity was measured from the ICG-containing test tube in each condition. In the clinical study, ICG angiography was applied to patients with colorectal cancer (n = 164). The quantitative perfusion parameters were the maximal fluorescence intensity (F_MAX ), slope, T_1/2MAX and perfusion time ratio (TR). Camera position, distance to colon, fluorescence emission source, surrounding lighting, site of angiography and ICG specific mode were considered as conditional factors and compared with the quantitative parameters to identify the optimal condition of ICG angiography.

RESULTS

The fluorescence intensity had an inverse correlation with distance, and the transitional zone was shown at a distance of 4-5 cm by slope differential. F_MAX , T_1/2MAX and slope were affected significantly by camera distance, site of angiography, fluorescence emission source and ICG mode as conditional factors. On multivariate analysis, F_MAX was independently associated with spectral ICG mode with red inversion, laser mode and camera distance. Conversely, TR was not related to any conditional factors.

CONCLUSION

Since quantitative parameters of ICG angiography are influenced by various conditions, a standardized protocol is required. The application of ICG specific modes with a constant distance of 4-5 cm can provide optimized fluorescence images.

Multifunctional Indocyanine Green Applications for Fluorescence-Guided Laparoscopic Colorectal Surgery

Indocyanine green (ICG) could be applied for multiple functions such as fluorescent tumor localization, fluorescence lymph node mapping (FLNM), and intraoperative angiography in colorectal cancer surgery. With the near-infrared (NIR) systems, colonoscopic ICG tattooing can be used to define the early colorectal cancer that cannot be easily distinguished through the serosal surface. The lymphatic pathways can be visualized under the NIR system when ICG is injected through the submucosal or subserosal layer around the tumor. Intraoperative ICG angiography can be applied to find a favorable perfusion segment before the colon transection. Although all fluorescence functions are considered essential steps in image-guided surgery, it is difficult to perform multifunctional ICG applications in a single surgical procedure at once because complex protocols could interfere with each other. Therefore, we review the multifunctional ICG applications for fluorescent tumor localization, FLNM, and ICG angiography. We also discuss the optimal protocol for fluorescence-guided colorectal surgery.

Intra-operative assessment of left-sided colorectal anastomotic integrity: a systematic review of available techniques

AIM

Anastomotic leak (AL) after colorectal resection is associated with increased rates of morbidity and mortality: potential permanent stoma formation, increased local recurrence, reduced cancer-related survival, poor functional outcomes and associated quality of life. Techniques to reduce leak rates are therefore highly sought.

METHOD

A literature search was performed for published full text articles using PubMed, Cochrane and Scopus databases with a focus on colorectal surgery 1990-2020. Additional papers were detected by scanning references of relevant papers.

RESULTS

A total of 53 papers were included after a thorough literature search. Techniques assessed included leak tests, endoscopy, perfusion assessment and fluorescence studies. Air-leak testing remains the most commonly used method across Europe, due to ease of reproducibility and low cost. There is no evidence that this reduces the leak rate; however, identification of a leak intra-operatively provides the opportunity for either suture reinforcement or formal takedown with or without re-do of the anastomosis and consideration of diversion. Suture repair alone of a positive air-leak test is associated with an increased AL rate. The use of fluorescence studies to guide the site of anastomosis has demonstrated reduced leak rates in distal anastomoses, is safe, feasible and has a promising future.

CONCLUSION

Although over reliance on any assessment tool should be avoided, intra-operative techniques with the aim of reducing AL rates are increasingly being employed. Standardization of these methods is imperative for routine use. However, in the interim it is recommended that all anastomoses should be assessed intra-operatively for mechanical failure, particularly distal anastomoses.

Incidence and risk factors for fluorescence abnormalities on near-infrared imaging using indocyanine green in stapled functional end-to-end anastomosis in laparoscopic colectomy

PURPOSE

Recently, several studies have suggested that near-infrared (NIR) imaging using indocyanine green (ICG) may contribute to the reduction of anastomotic leakage (AL) after colorectal cancer (CRC) surgery. However, few reports have focused on the usefulness of NIR imaging for AL after stapled functional end-to-end anastomosis (stapled FEEA). The purpose of this study was to clarify the frequency of fluorescence abnormalities on NIR imaging, in cases reconstructed with stapled FEEA.

METHODS

This retrospective study included patients with colon or appendiceal cancer who underwent laparoscopic colectomy with stapled FEEA reconstruction between March 2016 and August 2019.

RESULTS

A total of 400 patients who were managed at our three institutions were included in the present study. The rate of Clavien-Dindo (CD) grade > III AL was 1.0% (4/400). The median length of postoperative hospital stay was 7 days (IQR 25-75th percentile 6-8 days). In 11 patients (2.8%), the transection line was changed by NIR imaging, due to fluorescence abnormalities. The rate of transverse colon involvement in anastomosis was significantly higher in cases with fluorescence abnormalities than in cases with normal fluorescence (p = 0.035).

CONCLUSIONS

The frequency of fluorescence abnormalities on NIR was 2.8% in cases of colon resection with reconstruction by using stapled FEEA. There was a probability of abnormal fluorescence on NIR in cases where the transverse colon was involved in the anastomosis. This means that NIR may have potential benefit in such cases.

TRIAL REGISTRATION

UMIN000039977.

Simultaneous computer-assisted assessment of mucosal and serosal perfusion in a model of segmental colonic ischemia

BACKGROUND

Fluorescence-based enhanced reality (FLER) enables the quantification of fluorescence signal dynamics, which can be superimposed onto real-time laparoscopic images by using a virtual perfusion cartogram. The current practice of perfusion assessment relies on visualizing the bowel serosa. The aim of this experimental study was to quantify potential differences in mucosal and serosal perfusion levels in an ischemic colon segment.

METHODS

An ischemic colon segment was created in 12 pigs. Simultaneous quantitative mucosal and serosal fluorescence imaging was obtained via intravenous indocyanine green injection (0.2 mg/kg), using two near-infrared camera systems, and computer-assisted FLER analysis. Lactate levels were measured in capillary blood of the colonic wall at seven regions of interest (ROIs) as determined with FLER perfusion cartography: the ischemic zone (I), the proximal and distal vascularized areas (PV, DV), and the 50% perfusion threshold proximally and distally at the mucosal and serosal side (P50M, P50S, D50M, D50S).

RESULTS

The mean ischemic zone as measured (mm) for the mucosal side was significantly larger than the serosal one (56.3 ± 21.3 vs. 40.8 ± 14.9, p = 0.001) with significantly lower lactate values at the mucosal ROIs. There was a significant weak inverse correlation between lactate and slope values for the defined ROIs (r = - 0.2452, p = 0.0246).

CONCLUSIONS

Mucosal ischemic zones were larger than serosal zones. These results suggest that an assessment of bowel perfusion from the serosal side only can underestimate the extent of ischemia. Further studies are required to predict the optimal resection margin and anastomotic site.

Complicated Diverticular Disease

The modern management of colonic diverticular disease involves grouping patients into uncomplicated or complicated diverticulitis, after which the correct treatment paradigm is instituted. Recent controversies suggest overlap in management strategies between these two groups. While most reports still support surgical intervention for the treatment of complicated diverticular disease, more data are forthcoming suggesting complicated diverticulitis does not merit surgical resection in all scenarios. Given the significant risk for complication in surgery for diverticulitis, careful attention should be paid to patient and procedure selection. Here, we define complicated diverticulitis, discuss options for surgical intervention, and explain strategies for avoiding operative pitfalls that result in early and late postoperative complications.

Indocyanine Green-Enhanced Colorectal Surgery-between Being Superfluous and Being a Game-Changer

Nowadays, surgical innovations incorporate new technological conquests and must be validated by evidence-based medicine. The use of augmented reality-assisted indocyanine green (ICG) fluorescence has generated a myriad of intraoperative applications such as demonstration of key anatomical landmarks, sentinel lymph nodes, and real-time assessment of local blood flow. This paper presents a systematic review of the clinical evidence regarding the applications of ICG near-infrared (NIR) fluorescence in colorectal surgery. After we removed duplicate publications and screened for eligibility, a total of 36 articles were evaluated: 23 on perfusion assessment, 10 on lymph node mapping, and 3 on intraoperative identification of ureters. Lack of homogenous studies, low statistical power, and confounding evidence were found to be common amongst publications supporting the use of ICG in colorectal surgery, raising concerns over this seductive technique's cost efficiency and redundancy. The compiled data showed that ICG NIR fluorescence may be a game-changer in particular situations, as proven for low colorectal anastomosis or lateral pelvic lymph node dissection, but it remains controversial for routine use and sentinel lymph node assessment. Further randomized studies are needed to confirm these conclusions. Future research directions include tumor-targeted fluorescence imaging and digital software for quantitative evaluation of fluorescence.

A prospective study of real-time identification of line of transection in robotic colorectal cancer surgery by ICG

Colorectal cancer is the second most common cancer in women and the third most common cancer in men in the world. Surgical resection is the gold standard treatment and minimally invasive surgery remains the standard of care. Anastomotic leakage is one of the most feared postoperative complications in colorectal surgery. Although several factors have been identified as possible causes of anastomotic leakage (i.e., surgical techniques, patient risk factors, suture material or devices), the complete pathogenesis is still unclear. The reported leak rate ranges from 1 to 30% and increases as the anastomosis is more distal. To date the most widely used methods to assess tissue perfusion includes the surgeon intraoperative visual judgement based on the colour; bleeding edges of resected margins; pulsation and temperature, thereby resulting in either excess or insufficient colonic resection. Earlier studies in colorectal surgery have suggested that assessment of tissue perfusion by the clinical judgment of the operating surgeon underestimated the risk of anastomotic leakage. Indocyanine green (ICG) is a intravenous dye which has shown promise in identifying the bowel vascularity real time. Earlier studies on colorectal cancer have shown that ICG based detection of bowel vascularity is technically possible and has reduced the anastomotic leak rates in 16.7% of patients. We conducted a prospective study on patients with ICG guided bowel perfusion during robotic colorectal cancer surgery. The method is technically easy, reproducible and safe. This technique has changed the intraoperative decision in 88% of patients. Larger studies are needed before this can become the standard of care.

Clinical efficacy of bowel perfusion assessment during laparoscopic colorectal resection using laser speckle contrast imaging: A matched case-control study

INTRODUCTION

Disadvantages of bowel perfusion assessment with indocyanine green fluorescence angiography include the need for a fluorophore and the subjective nature of the assessment. This study was performed to evaluate the clinical efficacy of bowel perfusion assessment using laser speckle contrast imaging (LSCI) during laparoscopic colorectal surgery.

METHODS

The study population comprised the first 27 consecutive patients who underwent laparoscopic left-sided colorectal resection with intraoperative perfusion assessment using LSCI. The operative outcomes of these patients were compared with those of a matched group of patients without perfusion assessment. We analyzed the flux data expressed in laser speckle perfusion units.

RESULTS

After propensity score matching, we found no significant between-group differences in the patients' characteristics with the exception of the cancer stage. No patients undergoing LSCI perfusion assessment developed anastomotic leakage, but five (18.5%) patients in the control group did, at a significantly higher rate in male patients (P = .042). There were no significant differences in other operative outcomes. The laser speckle perfusion unit values after ligating marginal vessels were significantly lower than before ligation (P < .01).

CONCLUSIONS

With respect to anastomotic leakage, LSCI may improve patient outcomes after colorectal surgery. This technique appears to be a superior tool with the advantages of measurement repeatability and quantitativity and no need for a fluorophore.

Evaluation of characteristics of left-sided colorectal perfusion in elderly patients by angiography

BACKGROUND

Handling of the inferior mesenteric artery (IMA) and maintaining anastomotic perfusion are important in radical resection of left-sided colorectal cancer. However, the branching of this artery and the drainage patterns of this vein vary among individuals, and the characteristics and perfusion region of this artery in elderly patients remain unclear.

AIM

To evaluate the characteristics and perfusion region of the IMA in elderly patients using angiography.

METHODS

We enrolled 154 patients (> 65 years old) who underwent digital subtraction angiography of the IMA. The characteristics, bifurcation, and distribution of the IMA and termination of the anastomotic perfusion of the left colon and rectum were examined using digital subtraction angiography. Collateral arterial arches and the IMA hemoperfusion region were also recorded. Perfusion regions were cross-referenced with clinical and anatomical features by the univariate analysis.

RESULTS

Of 154 patients, 25 (16.2%) had IMA lesions. The left colic artery arose independently from the IMA in 44.2% of patients, shared a trunk with the sigmoid artery in 35.1%, shared an opening with the sigmoid and superior rectal arteries in 16.9%, and was absent in 5.1%. The IMA perfusion region stopped at the splenic flexure in 50 (32.5%) patients. The collateral circulation existed in the colonic perfusion region, including the marginal artery (Drummond’s artery), the ascending branch of the left colonic artery to supply the transverse colon, and the arc of Riolan with a frequency of 100%, 22.7%, and 1.9%, respectively. The IMA perfusion region was independently associated with the comorbidity of atherosclerosis, IMA atherosclerotic lesion, branching pattern, collateral circulation, and marginal artery integrity.

CONCLUSION

The IMA and its branches are prone to arteriosclerosis, and IMA perfusion may be interrupted at the splenic flexure in elderly patients. The applicability and precision of preoperative angiography for evaluating the IMA branching and perfusion patterns could facilitate geriatric laparoscopic left-sided colorectal cancer surgery with suspicion of poor IMA perfusion.

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.

Visualization and quantification of anastomotic perfusion in colorectal surgery using near-infrared fluorescence

BACKGROUND

Anastomotic leakage (AL) is one of the most troublesome complications in colorectal surgery. Recently, near-infrared fluorescence (NIRF) imaging has been used intraoperatively to detect sentinel lymph nodes and visualize the blood supply at the region of interest (ROI). The aim of this study was to evaluate the role of visualization and quantification of bowel perfusion around the anastomosis using NIRF system in predicting AL.

METHODS

A prospective study was conducted on patients who had laparoscopic surgery for colorectal cancer at our institution. Perfusion of the anastomosis was evaluated with NIRF imaging after intravenous injection of indocyanine green (ICG). The time course of fluorescence intensity was recorded by an imaging analyzer We measured the time from ICG injection to the beginning of fluorescence (T₀), maximum intensity (I_max), time to reach I_max (T_max), time to reach I_max 50% ([Formula: see text]) and slope (S) after the anastomosis.

RESULTS

Tumor locations were as follows; cecum: 2, ascending colon: 2, transverse colon: 7, descending colon: 1, sigmoid colon: 2, rectosigmoid colon: 3 and rectum: 6 (one case with synchronous cancer). All operations were performed laparoscopically. Four patients were diagnosed with or suspected to have AL (2 patients with grade B anastomotic leakage after low anterior resection, 1 patient with minor leakage in transverse colon resection and 1 patient needing re-anastomosis intraoperatively in transverse colon resection). T₀ was significantly longer in the AL group than in patients without AL (64.3 ± 27.6 and 18.2 ± 6.6 s, p = 2.2 × 10^-3).

CONCLUSIONS

Perfusion of the anastomosis could be successfully visualized and quantified using NIRF imaging with ICG. T₀ might be a useful parameter for prediction of AL.

The significance of intraoperative fluorescence angiography in miniinvasive low rectal resections

Introduction

Anastomotic leak is a very serious complication in colorectal surgery. Tissue perfusion of the anastomosis plays an integral role in its multifactorial etiology. Fluorescence angiography using indocyanine green allows visualization of perfusion in real time.

Aim

To evaluate the effectiveness of intraoperative fluorescence angiography as a tool to decrease the incidence of anastomotic leak after laparoscopic or robotic low resection of the rectum for cancer.

Material and methods

Intraoperative fluorescence angiography was performed sequentially in 50 patients during low rectal resection for cancer with total mesorectal excision, primary anastomosis and protective ileostomy using laparoscopic or robotic technique. The results were compared to a historical control group of 50 patients with the same procedure without the use of fluorescence angiography.

Results

The patient sets were comparable in basic demographic and clinical parameters. Intraoperative visualization of perfusion by fluorescence angiography was achieved in all patients without unwanted side-effects. In 6 (12%) patients, the resection line was adjusted based on the fluorescence angiography. The incidence of anastomotic leak was insignificantly lower in the group with fluorescence angiography (18% vs. 10%), which led to significantly shorter hospital stay. Other postoperative complications were comparable between the two groups.

Conclusions

Fluorescence angiography using indocyanine green is a safe and effective method with the potential of reducing anastomotic leak during minimally invasive low resection of the rectum for cancer.

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.

Laser Speckle Contrast Imaging for Intraoperative Quantitative Assessment of Intestinal Blood Perfusion During Colorectal Surgery: A Prospective Pilot Study

BACKGROUND

The main limitation of perfusion assessment with indocyanine green fluorescence angiography during colorectal surgery is that the surgeon assesses the quality of perfusion subjectively. The ideal intestinal viability test must be minimally invasive, objective, and reproducible. We evaluated the quantitativity and reproducibility of laser speckle contrast imaging for perfusion assessment during colorectal surgery.

METHODS

This was a prospective, nonrandomized, pilot study of 8 consecutive patients who underwent elective left-sided colorectal resection. Laser speckle perfusion images at the site of proximal transection of the bowel were obtained intraoperatively. We tested the hypothesis that laser speckle contrast imaging was able to quantitatively identify areas of diminished intestinal perfusion after devascularization and assessed the reproducibility of this method.

RESULTS

All surgical procedures were uneventful and blood flow measurements were successfully made in all patients. None of the patients developed postoperative complications related to the anastomosis and stoma. Data analyses were successfully optimized to perform quantitative regional perfusion assessments in all cases. The bowel tissue blood flows of the anal side region adjacent to the transection line were significantly lower than those of the oral side region adjacent to the transection line after ligation of marginal vessels ( P = .012). Interrater reliability was high (intraclass correlation coefficients = 0.989), and a Bland-Altman plot showed few differences of mean flux data between 2 investigators.

CONCLUSION

Laser speckle contrast imaging is feasible for real-time assessment of bowel perfusion with quantitativity and excellent reproducibility during colorectal surgery without administration of any contrast agents.

Does near-infrared (NIR) fluorescence angiography modify operative strategy during emergency procedures?

INTRODUCTION

Bowel viability can be difficult to evaluate during emergency surgery. Near-infrared (NIR) fluorescence angiography allows an intraoperative assessment of organ perfusion during elective surgery and might help to evaluate intestinal perfusion during emergency procedures. The aim of this study was to assess if NIR modified operative strategy during emergency surgery.

MATERIALS AND METHODS

From July 2014 to December 2015, we prospectively evaluated all consecutive patients, who had NIR assessment during emergency surgery. Primary endpoint was the modification of operative strategy after the assessment with NIR. Secondary endpoints were general post-operative outcomes, including reoperation rate.

RESULTS

Fifty-six patients were included in the study. Mean age was 64 ± 17 years. An exploratory laparoscopy was performed in 39% (n = 22) and an open surgery in 61% of cases (n = 34). Conversion rate to open surgery was 41% (n = 9). 32 patients had a bowel resection. In 32% of the cases (n = 18), the result of the NIR test led to a modification of the operative strategy. Among them, 33% (n = 6) had a larger resection or a resection, which was initially not planned. The other 12 patients (67%) had finally no resection, which was initially thought to be performed. Importantly, none of those patients needed a reoperation for ischemia. Mean time for performing NIR test was 167 s (± 121). Overall reoperation rate was 16.1% (n = 9). Two patients had an anastomotic leak. Eight patients (14.3%) died within the first 30 post-operative days; however, none of them presented a bowel ischemia or an anastomotic leak.

CONCLUSION

NIR is an easy and short procedure, which can be performed during emergency surgery to assess bowel perfusion. It may help the surgeon to preserve intestinal length or to define the exact limits of resection. Overall, we report a modification of operative strategy in up to one-third of evaluated patients.

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.

Green indocyanine fluorescence in robotic abdominal surgery

Fluorescent imaging with indocyanine green (ICG) is an emerging technology that is gaining acceptance for being a valid tool in surgeons' decision making. ICG binds to plasma lipoproteins if injected intravenously and, when excited by near-infrared light, provides anatomic information about organs vascularization and tissues perfusion. If injected in tissues, it migrates in the lymphatic system, therefore enabling the identification of lymphatic draining pathways of different organs. In this paper we address specific applications of ICG fluorescence in robotic general surgery.

IntAct: intra-operative fluorescence angiography to prevent anastomotic leak in rectal cancer surgery: a randomized controlled trial

AIM

Anastomotic leak (AL) is a major complication of rectal cancer surgery. Despite advances in surgical practice, the rates of AL have remained static, at around 10-15%. The aetiology of AL is multifactorial, but one of the most crucial risk factors, which is mostly under the control of the surgeon, is blood supply to the anastomosis. The MRC/NIHR IntAct study will determine whether assessment of anastomotic perfusion using a fluorescent dye (indocyanine green) and near-infrared laparoscopy can minimize the rate of AL leak compared with conventional white-light laparoscopy. Two mechanistic sub-studies will explore the role of the rectal microbiome in AL and the predictive value of CT angiography/perfusion studies.

METHOD

IntAct is a prospective, unblinded, parallel-group, multicentre, European, randomized controlled trial comparing surgery with intra-operative fluorescence angiography (IFA) against standard care (surgery with no IFA). The primary end-point is rate of clinical AL at 90 days following surgery. Secondary end-points include all AL (clinical and radiological), change in planned anastomosis, complications and re-interventions, use of stoma, cost-effectiveness of the intervention and quality of life. Patients should have a diagnosis of adenocarcinoma of the rectum suitable for potentially curative surgery by anterior resection. Over 3 years, 880 patients from 25 European centres will be recruited and followed up for 90 days.

DISCUSSION

IntAct will rigorously evaluate the use of IFA in rectal cancer surgery and explore the role of the microbiome in AL and the predictive value of preoperative CT angiography/perfusion scanning.

A practical guide for the use of indocyanine green and methylene blue in fluorescence-guided abdominal surgery

Near-infrared (NIR) fluorescence imaging is gaining clinical acceptance over the last years and has been used for detection of lymph nodes, several tumor types, vital structures and tissue perfusion. This review focuses on NIR fluorescence imaging with indocyanine green and methylene blue for different clinical applications in abdominal surgery with an emphasis on oncology, based on a systematic literature search. Furthermore, practical information on doses, injection times, and intraoperative use are provided.

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.

Evaluation of Gastric Conduit Perfusion During Esophagectomy with Indocyanine Green Fluorescence Imaging

BACKGROUND

Anastomotic leakage is a determining factor of morbidity and mortality after an esophagectomy. An adequate blood supply of the gastric conduit is vital to prevent this complication. We aimed to determine the feasibility and usefulness of indocyanine green (ICG) fluorescence imaging to evaluate the gastric conduit perfusion during an esophagectomy.

METHODS

Patients with distal esophageal cancer or esophagogastric junction cancer scheduled for esophagectomy were enrolled in this study. After pulling up the gastric conduit into the chest and before performing the anastomosis, 5 mg of ICG was injected as a bolus. Visual assessment of the blood supply of the gastric conduit was compared with the ICG fluorescence imaging pattern of perfusion.

RESULTS

Five patients were included in this study. Hybrid Ivor Lewis esophagectomy (laparoscopic abdomen and right thoracotomy) was performed in all cases. In all patients, visual assessment of the perfusion of the stomach determined that the conduit was well perfused. In two patients (40%), ICG fluorescence showed an inadequate blood supply of the conduit's tip. Resection of the devitalized portion of the conduit was performed in these two patients. No anastomotic leaks were recorded, and all patients had an uneventful postoperative course.

CONCLUSIONS

Visual assessment of the gastric conduit may underestimate perfusion and inadequate blood supply. ICG fluorescence imaging is a promising tool to determine the gastric conduit perfusion during an esophagectomy. Prospective studies with larger series are warranted to confirm the usefulness of ICG fluorescence imaging during an esophagectomy.

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.

Clinical role of fluorescence imaging in colorectal surgery - a review

INTRODUCTION

Anastomotic leak (AL) after colorectal surgery is a devastating complication; decreased blood perfusion is an important risk factor. Surgeons rely on subjective measures to assess bowel perfusion. Fluorescence imaging (FI) with indocyanine green (ICG) provides a real-time objective assessment of intestinal perfusion. Areas covered: A PubMed search using the terms 'fluorescence imaging', 'indocyanine green', 'colon and rectal surgery' was undertaken. Sixteen articles between 2010 to present were identified. Main outcomes were leak rate reduction, change in surgical plan, and technical feasibility. Change in surgical strategy due to FI was recorded in 11 studies. Two case control studies showed overall reduction of 4% and 12% in AL rate and one showed no change in AL rate between groups. Expert commentary: According to the available literature, FI is technically feasible and alters surgical strategy in a non-negligible number of patients possibly effecting AL rates.