Fluorescence angiography likely protects against anastomotic leak in colorectal surgery: a systematic review and meta-analysis of randomised controlled trials

Indocyanine green fluorescence-guided surgery in the emergency setting: the WSES international consensus position paper

BACKGROUND

Decision-making in emergency settings is inherently complex, requiring surgeons to rapidly evaluate various clinical, diagnostic, and environmental factors. The primary objective is to assess a patient's risk for adverse outcomes while balancing diagnoses, management strategies, and available resources. Recently, indocyanine green (ICG) fluorescence imaging has emerged as a valuable tool to enhance surgical vision, demonstrating proven benefits in elective surgeries.

AIM

This consensus paper provides evidence-based and expert opinion-based recommendations for the standardized use of ICG fluorescence imaging in emergency settings.

METHODS

Using the PICO framework, the consensus coordinator identified key research areas, topics, and questions regarding the implementation of ICG fluorescence-guided surgery in emergencies. A systematic literature review was conducted, and evidence was evaluated using the GRADE criteria. A panel of expert surgeons reviewed and refined statements and recommendations through a Delphi consensus process, culminating in final approval.

RESULTS

ICG fluorescence imaging, including angiography and cholangiography, improves intraoperative decision-making in emergency surgeries, potentially reducing procedure duration, complications, and hospital stays. Optimal use requires careful consideration of dosage and timing due to limited tissue penetration (5-10 mm) and variable performance in patients with significant inflammation, scarring, or obesity. ICG is contraindicated in patients with known allergies to iodine or iodine-based contrast agents. Successful implementation depends on appropriate training, availability of equipment, and careful patient selection.

CONCLUSIONS

Advanced technologies and intraoperative navigation techniques, such as ICG fluorescence-guided surgery, should be prioritized in emergency surgery to improve outcomes. This technology exemplifies precision surgery by enhancing minimally invasive approaches and providing superior real-time evaluation of bowel viability and biliary structures-areas traditionally reliant on the surgeon's visual assessment. Its adoption in emergency settings requires proper training, equipment availability, and standardized protocols. Further research is needed to evaluate cost-effectiveness and expand its applications in urgent surgical procedures.

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.

Drainage Fluid Amylase as a Biomarker for the Detection of Anastomotic Leakage After Low Anterior Resection of Rectal Cancer: A Two-center Study

Aim

This study aimed to investigate the utility of measuring amylase levels in drainage fluid (DFA) for early, non-invasive detection of anastomotic leakage (AL) in undergoing low anterior resection (LAR) for rectal cancer.

Patients and Methods

This prospective observational cohort study analyzed drainage fluid samples from patients who underwent LAR for rectal cancer at two medical centers between February 2021 and December 2023. DFA levels were measured on postoperative days (PODs) 1, 3, and 5. AL was confirmed by clinical evidence and radiological imaging. Statistical analyses were performed to evaluate the diagnostic performance of DFA.

Results

Of 120 LAR cases, AL occurred in five (4.16%). DFA levels on POD 3 and 5 were significantly higher in the AL than in the non-AL group (p<0.0001). DFA on POD 5 had the highest diagnostic accuracy for early AL detection, with an area under the curve of 0.99, achieving 100% sensitivity and 99.5% specificity at a cutoff of 846 U/l. A DFA >846 U/l predicted AL with negative predictive and positive predictive values of 83.3% and 100%, respectively, on POD 5.

Conclusion

Measuring DFA is a non-invasive, simple and cost-effective method for early AL detection in patients with rectal cancer undergoing LAR. Our findings also suggested that drain placement may be useful for the early detection of AL through DFA measurement.

Knowledge, attitudes and practices of using Indocyanine Green (ICG) fluorescence in emergency surgery: an international web-based survey in the ARtificial Intelligence in Emergency and trauma Surgery (ARIES)-WSES project

Fluorescence imaging is a real-time intraoperative navigation modality to enhance surgical vision and it can guide emergency surgeons while performing difficult, high-risk surgical procedures. The aim of this study is to assess current knowledge, attitudes, and practices of emergency surgeons in the use of indocyanine green (ICG) in emergency settings. Between March 08, 2023 and April 10, 2023, a questionnaire composed of 27 multiple choice and open-ended questions was sent to 200 emergency surgeons who had previously joined the ARtificial Intelligence in Emergency and trauma Surgery (ARIES) project promoted by the WSES. The questionnaire was developed by an emergency surgeon with an interest in advanced technologies and artificial intelligence. The response rate was 96% (192/200). Responders affirmed that ICG fluorescence can support the performance of difficult surgical procedures in the emergency setting, particularly in the presence of severe inflammation and in evaluating bowel viability. Nevertheless, there were concerns regarding accessibility and availability of fluorescence imaging in emergency settings. Eighty-seven out of 192 (45.3%) respondents have a fluorescence imaging system of vision for both elective and emergency surgical procedures; 32.3% of respondents have this system solely for elective procedures; 21.4% of respondents do not have this system, 15% do not have experience with it, and 38% do not use this imaging in emergency surgery. Less than 1% (2/192) affirmed that ICG fluorescence changed always their intraoperative decision-making. Precision surgery effectively tailors surgical interventions to individual patient characteristics using advanced technology, data analysis and artificial intelligence. ICG fluorescence can serve as a valid and safe tool to guide emergency surgery in different scenarios, such as intestinal ischemia and severe acute cholecystitis. Due to the lack of high-level evidence within this field, a consensus of expert emergency surgeons is needed to encourage stakeholders to increase the availability of fluorescence imaging systems and to support emergency surgeons in implementing ICG fluorescence in their daily practice.

Indocyanine green fluorescence applied to gynecologic oncology: beyond sentinel lymph node

Indocyanine green (ICG), a well-known molecule employed in medicine for over five decades, has emerged as a versatile dye widely embraced across various surgical disciplines. In gynecologic oncology, its prevalent use revolves around the detection of sentinel lymph nodes. However, the true potential of ICG extends beyond this singular application, owing to its pragmatic utility, cost-effectiveness, and safety profile. Furthermore, ICG has been introduced in the theranostic landscape, marking a significant juncture in the evolution of its clinical utility. This narrative review aims to describe the expanding horizons of ICG fluorescence in gynecologic oncology, beyond the sentinel lymph node biopsy. The manifold applications reported within this manuscript include: 1) lymphography; 2) angiography; 3) nerve visualization; 4) ICG-driven resections; and 5) theranostic. The extensive exploration across these numerous applications, some of which are still in the preclinical phase, serves as a hypothesis generator, aiming to stimulate the development of clinical studies capable of expanding the use of this drug in our field, enhancing the care of gynecological cancer patients.

Perfusion outcomes with near-infrared indocyanine green imaging system in laparoscopic total mesorectal excision for mid-rectal or low-rectal cancer (POSTER): a study protocol

INTRODUCTION

Anastomotic leakage (AL) is defined as the failure of complete healing or disruption of the anastomosis subsequent to rectal cancer surgery, resulting in the extravasation of intestinal contents into the intra-abdominal or pelvic cavity. It is a serious complication of rectal cancer surgery, accounting for a considerable increase in morbidity and mortality. The use of fluorescence imaging technology in surgery allows surgeons to better evaluate blood perfusion. However, the conclusions of some existing studies are not consistent, so a consensus on whether the near-infrared indocyanine green (NIR-ICG) imaging system can reduce the incidence of AL is needed.

METHODS

This POSTER trial is designed as a multicentre, prospective, randomised controlled clinical study adhering to the "population, interventions, comparisons, outcomes (PICO)" principles. It is scheduled to take place from August 2019 to December 2024 across eight esteemed hospitals in China. The target population consists of patients diagnosed with rectal cancer through pathological confirmation, with tumours located≤10 cm from the anal verge, eligible for laparoscopic surgery. Enrolled patients will be randomly assigned to either the intervention group or the control group. The intervention group will receive intravenous injections of ICG twice, with intraoperative assessment of anastomotic blood flow using the near-infrared NIR-ICG system during total mesorectal excision (TME) surgery. Conversely, the control group will undergo conventional TME surgery without the use of the NIR-ICG system. A 30-day follow-up period postoperation will be conducted to monitor and evaluate occurrences of AL. The primary endpoint of this study is the incidence of AL within 30 days postsurgery in both groups. The primary outcome investigators will be blinded to the application of ICG angiography. Based on prior literature, we hypothesise an AL rate of 10.3% in the control group and 3% in the experimental group for this study. With a planned ratio of 2:1 between the number of cases in the experimental and control groups, and an expected 20% lost-to-follow-up rate, the initial estimated sample size for this study is 712, comprising 474 in the experimental group and 238 in the control group.

ETHICS AND DISSEMINATION

This study has been approved by Ethics committee of Beijing Friendship Hospital, Capital Medical University (approval number: 2019-P2-055-02). The results will be disseminated in major international conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04012645.

Quantification of fluorescence angiography for visceral perfusion assessment: measuring agreement between two software algorithms

BACKGROUND

Indocyanine green fluorescence angiography (ICG-FA) may reduce perfusion-related complications of gastrointestinal anastomosis. Software implementations for quantifying ICG-FA are emerging to overcome a subjective interpretation of the technology. Comparison between quantification algorithms is needed to judge its external validity. This study aimed to measure the agreement for visceral perfusion assessment between two independently developed quantification software implementations.

METHODS

This retrospective cohort analysis included standardized ICG-FA video recordings of patients who underwent esophagectomy with gastric conduit reconstruction between August 2020 until February 2022. Recordings were analyzed by two quantification software implementations: AMS and CPH. The quantitative parameter used to measure visceral perfusion was the normalized maximum slope derived from fluorescence time curves. The agreement between AMS and CPH was evaluated in a Bland-Altman analysis. The relation between the intraoperative measurement of perfusion and the incidence of anastomotic leakage was determined for both software implementations.

RESULTS

Seventy pre-anastomosis ICG-FA recordings were included in the study. The Bland-Altman analysis indicated a mean relative difference of + 58.2% in the measurement of the normalized maximum slope when comparing the AMS software to CPH. The agreement between AMS and CPH deteriorated as the magnitude of the measured values increased, revealing a proportional (linear) bias (R2 = 0.512, p < 0.001). Neither the AMS nor the CPH measurements of the normalized maximum slope held a significant relationship with the occurrence of anastomotic leakage (median of 0.081 versus 0.074, p = 0.32 and 0.041 vs 0.042, p = 0.51, respectively).

CONCLUSION

This is the first study to demonstrate technical differences in software implementations that can lead to discrepancies in ICG-FA quantification in human clinical cases. The possible variation among software-based quantification methods should be considered when interpreting studies that report quantitative ICG-FA parameters and derived thresholds, as there may be a limited external validity.

Indocyanine green fluorescence angiography could reduce the risk of anastomotic leakage in rectal cancer surgery: a systematic review and meta-analysis of randomized controlled trials

AIM

Several papers have shown that use of indocyanine green (ICG) decreases incidence of anastomotic leakage (AL) during colonic surgery, but no clear evidence has been found for rectal cancer surgery. Therefore, with this systematic review and meta-analysis of randomized controlled trials (RCTs) we aimed to assess if ICG could also reduce risk of AL in rectal cancer surgery.

METHOD

PubMed, Scopus, CINAHL and Cochrane databases were searched for RCTs assessing the effect of intraoperative ICG on the incidence of AL of the colorectal anastomosis. Pooled relative risk (RR) and pooled risk difference (RD) were obtained using models with random effects. Risk of bias was evaluated with the Rob2 tool and the quality of evidence was assessed using the GRADE Pro tool.

RESULTS

Four RCTs were included for analysis, with a total of 1510 patients (743 controls and 767 ICG patients). The rate of AL was 9% in the ICG group (69/767) and 13.9% (103/743) in the control group (p = 0.003, RR -0.5, 95% CI -0.827 to -0.172, heterogeneity test 0%, p = 0.460). The RD in terms of incidence of AL was significantly decreased by 4.51% (p = 0.031, 95% CI -0.086 to -0.004, heterogeneity test 28%, p = 0.182) when using ICG.

CONCLUSION

Our meta-analysis suggested that use of ICG during rectal cancer surgery could reduce the rate of AL.

Inferior mesenteric artery ligation level in rectal cancer surgery: still no answer-a systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis is to summarize the current scientific evidence regarding the impact of the level of inferior mesenteric artery (IMA) ligation on post-operative and oncological outcomes in rectal cancer surgery.

METHODS

We conducted a systematic review of the literature up to 06 September 2022. Included were RCTs that compared patients who underwent high (HL) vs. anterior (LL) IMA ligation for resection of rectal cancer. The literature search was performed on Medline/PubMed, Scopus, and the Web of Science without any language restrictions. The primary endpoint was overall anastomotic leakage (AL). Secondary endpoints were oncological outcomes, intraoperative complications, urogenital functional outcomes, and length of hospital stay.

RESULTS

Eleven RCTs (1331 patients) were included. The overall rate of AL was lower in the LL group, but the difference was not statistically significant (RR 1.43, 95% CI 0.95 to 2.96). The overall number of harvested lymph nodes was higher in the LL group, but the difference was not statistically significant (MD 0.93, 95% CI - 2.21 to 0.34). The number of lymph nodes harvested was assessed in 256 patients, and all had a laparoscopic procedure. The number of lymph nodes was higher when LL was associated with lymphadenectomy of the vascular root than when IMA was ligated at its origin, but there the difference was not statistically significant (MD - 0.37, 95% CI - 1.00 to 0.26). Overall survival at 5 years was slightly better in the LL group, but the difference was not statistically significant (RR 0.98, 95% CI 0.93 to 1.05). Disease-free survival at 5 years was higher in the LL group, but the difference was not statistically significant (RR 0.97, 95% CI 0.89 to 1.04).

CONCLUSIONS

There is no evidence to support HL or LL according to results in terms of AL or oncologic outcome. Moreover, there is not enough evidence to determine the impact of the level of IMA ligation on functional outcomes. The level of IMA ligation should be chosen case by case based on expected functional and oncological outcomes.

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.

[Fluorescence angiography in colorectal surgery]

OBJECTIVE

To evaluate the impact of indocyanine green fluorescence angiography on the incidence of colorectal anastomotic leakage.

MATERIAL AND METHODS

We summarized the results of non-comparative and randomized clinical trials, as well as meta-analyses.

RESULTS

Indocyanine green fluorescence angiography changes the anastomosis site in 10% of patients due to inadequate blood supply to intestinal wall at the initially scheduled level. This method can decrease the incidence of «low» colorectal anastomosis leakage.

CONCLUSION

Routine intraoperative fluorescence angiography with indocyanine green can become a standard method for prevention of colorectal anastomotic leakage.