Intraoperative laser fluorescence angiography in colorectal surgery: a noninvasive analysis to reduce the rate of anastomotic leakage

Impact of Low Ligation on Bowel Perfusion and Anastomotic Leakage in Minimally Invasive Rectal Cancer Surgery: A Post Hoc Analysis of a Randomized Controlled Trial

BACKGROUND

Whether the level of the inferior mesenteric artery ligation affects the incidence of anastomotic leakage remains unclear.

OBJECTIVE

To assess the impact of the level of inferior mesenteric artery ligation on blood flow to the anastomotic site and the incidence of anastomotic leakage using indocyanine green fluorescence imaging.

DESIGN

A post hoc analysis of the EssentiAL trial.

SETTINGS

This study was conducted at 41 tertiary referral centers in Japan.

PATIENTS

A total of 839 patients with rectal cancer (<12 cm from the anal verge) were included.

MAIN OUTCOME MEASURES

The incidence of anastomotic leakage and perfusion status were compared between the high and low ligation groups.

RESULTS

The median fluorescence time was similar at 25 seconds in both groups (p = 0.74). Although no statistical difference was noted, the high ligation group was more likely to have greater outliers in fluorescence time compared to the low ligation group. The high ligation group demonstrated higher poor perfusion rates than the low ligation group (2.8% vs 1.5%). In the high ligation group, anastomotic leakage occurred in 1 case of poor perfusion where additional resection was not performed by the surgeon's intraoperative judgment. In addition, the additional resection rate nearly doubled with the use of indocyanine green fluorescence imaging. After propensity score matching (129 patients per group), the overall anastomotic leakage rate was 13.2% in the high ligation group and 10.9% in the low ligation group ( p = 0.57).

LIMITATIONS

This study was a post hoc analysis, the sample size was small, and the anastomosis methods varied.

CONCLUSIONS

The level of inferior mesenteric artery ligation did not affect blood flow at the anastomotic site or the incidence of anastomotic leakage statistically, but assessing bowel perfusion using indocyanine green fluorescence imaging can offer clinical benefits, optimizing patient outcomes. See Video Abstract .

TRIAL REGISTRATION

The Japan Registry of Clinical Trials (jRCTs-CRB3180007), the Japanese Clinical Trials Registry (UMIN-CTR000030240).

IMPACTO DE LA LIGADURA BAJA EN LA PERFUSIN INTESTINAL Y LA FUGA ANASTOMTICA EN LA CIRUGA MNIMAMENTE INVASIVA DEL CNCER RECTAL UN ANLISIS POST HOC DE UN ENSAYO CONTROLADO ALEATORIZADO

ANTECEDENTES:No está claro si el nivel de la ligadura de la arteria mesentérica inferior afecta la incidencia de fuga anastomótica.OBJETIVO:Evaluar el impacto del nivel de ligadura de la arteria mesentérica inferior en el flujo sanguíneo al sitio de la anastomosis y la incidencia de fuga anastomótica mediante imágenes de fluorescencia con verde de indocianina.DISEÑO:Análisis post hoc del ensayo EssentiAL.ESCENARIO:Este estudio se realizó en 41 centros de referencia terciarios en Japón.PACIENTES:839 pacientes con cáncer rectal (<12 cm desde el márgen anal).PRINCIPALES MEDIDAS DE RESULTADOS:Se compararon la incidencia de fuga anastomótica y el estado de perfusión entre los grupos de ligadura alta y baja.RESULTADOS:El tiempo de fluorescencia medio fue similar a 25 segundos en ambos grupos (p = 0.74). Aunque no se observó ninguna diferencia estadística, el grupo de ligadura alta tuvo más probabilidades de tener mayores valores atípicos en el tiempo de fluorescencia en comparación con el grupo de ligadura baja. El grupo de ligadura alta demostró tasas de perfusión deficiente más altas que el grupo de ligadura baja (2.8 % frente a 1.5 %). En el grupo de ligadura alta, se produjo una fuga anastomótica en un caso de perfusión deficiente en el que no se realizó una resección adicional según el criterio intraoperatorio del cirujano. Además, la tasa de resección adicional casi se duplicó con el uso de imágenes de fluorescencia con verde de indocianina. Después de la comparación por puntaje de propensión (129 pacientes por grupo), la tasa general de fuga anastomótica fue del 13.2 % en el grupo de ligadura alta y del 10.9 % en el grupo de ligadura baja ( p = 0.57).LIMITACIONES:Este estudio fue un análisis post hoc, el tamaño de la muestra fue pequeño y los métodos de anastomosis variaron.CONCLUSIONES:El nivel de ligadura de la arteria mesentérica inferior no afectó estadísticamente el flujo sanguíneo en el sitio de la anastomosis ni la incidencia de fuga anastomótica, pero la evaluación de la perfusión intestinal mediante imágenes de fluorescencia con verde de indocianina puede ofrecer beneficios clínicos, optimizando los resultados del paciente. (Traducción-Dr. Jorge Silva Velazco)REGISTRO DEL ENSAYO:Registro japonés de ensayos clínicos (jRCTs-CRB3180007), Registro japonés de ensayos clínicos (UMIN-CTR000030240).

Possibility of preventing intra-abdominal infection by lymph node mapping with indocyanine green in robotic gastrectomy

BACKGROUND

Intra-abdominal infection can be an onerous and fatal complication of radical gastrectomy for gastric cancer. High drain amylase levels are closely related to pancreatic damage and intra-abdominal infection. We aimed to investigate whether robotic radical gastrectomy with lymph node mapping by indocyanine green tracer reduces drain amylase levels.

METHODS

Between March 2019 and July 2024, patients at our institution with clinical tumor stage cT1-T4a, N0/+, M0, and possibly treatable gastric cancer were enrolled in this study and divided into the indocyanine green group or the non-indocyanine green group based on the use of indocyanine green. One day before surgery, the patients in the indocyanine green group underwent endoscopic peritumoral injection of indocyanine green into the submucosa. Drain amylase levels on postoperative days 1 and 3, postoperative intra-abdominal infection, and perioperative outcomes were compared between the 2 groups.

RESULTS

There were no significant differences in patient background and pathologic factors between the 2 groups. Drain amylase levels on postoperative days 1 and 3 were significantly lower in the indocyanine green group than in the non-indocyanine green group, and postoperative hospital stay was shorter. The incidence of intra-abdominal infection was also significantly lower in the indocyanine green group than in the non-indocyanine green group. However, multivariate analysis of intra-abdominal infection showed a drain amylase level of 200 IU/L or higher on postoperative day 3 to be an independent risk factor for postoperative intra-abdominal infection, whereas indocyanine green use was not.

CONCLUSION

This study showed the clinical usefulness of robotic radical gastrectomy with lymph node mapping by indocyanine green. This procedure can reduce drain amylase levels and consequently may reduce the incidence of intra-abdominal infection.

Advancement of indocyanine green fluorescence imaging technology in laparoscopic surgery for rectal cancer

Indocyanine green fluorescence imaging technology has been increasingly utilized in rectal surgery in recent years. As a safe tracer, indocyanine green can facilitate lymph node tracing, assess the blood supply at anastomotic sites, and localize tumour lesions during laparoscopic surgery, thereby resulting in favourable outcomes. This technology helps surgeons to achieve more precise diagnoses and treatments in laparoscopic procedures, thus ultimately benefiting patients. However, the current application of indocyanine green fluorescence imaging technology still lacks standardized regulations, and certain effects remain contentious. This study provides a comprehensive review of the application of indocyanine green in laparoscopic surgery for rectal cancer based on the pertinent literature.

AUGUR-AIM: Clinical validation of an artificial intelligence indocyanine green fluorescence angiography expert representer

AIM

Recent randomized controlled trials and meta-analyses have demonstrated a reduction in the anastomotic leak rate when indocyanine green fluorescence angiography (ICGFA) is used versus when it is not in colorectal resections. We have previously demonstrated that an artificial intelligence (AI) model, AUGUR-AI, can digitally represent in real time where experienced ICGFA users would place their surgical stapler based on their interpretation of the fluorescence imagery. The aim of this study, called AUGUR-AIM, is to validate this method across multiple clinical sites with regard to generalizability, usability and accuracy while generating new algorithms for testing and determining the optimal mode of deployment for the software device.

METHOD

This is a prospective, observational, multicentre European study involving patients undergoing resectional colorectal surgery with ICGFA as part of their standard clinical care enrolled over a 1-year period. Video recordings of the ICGFA imagery will be computationally analysed both in real time and post hoc by AUGUR-AI, with the operating surgeon blinded to the results, testing developed algorithms iteratively versus the actual surgeon's ICGFA interpretation. AI-based interpretation of the fluorescence signal will be compared with the actual transection site selected by the operating surgeon and usability optimized.

CONCLUSION

AUGUR-AIM will validate the use of AUGUR-AI to interpret ICGFA imagery in real time to the level of an expert ICGFA user, building on our previous work to include a larger, more diverse patient and surgeon population. This could allow future progression to develop the AI model into a usable clinical tool that could provide decision support, including to new/infrequent ICGFA users, and documentary support of the decision made by experienced users.

Quantification of indocyanine green fluorescence angiography in colorectal surgery: a systematic review of the literature

BACKGROUND

Indocyanine green fluorescence angiography (ICGFA) during colorectal surgery associates with reduced post-operative anastomotic complication rates. Because its interpretation is subjective, quantification has been proposed to address inter-user variability. This study reviews the published literature regarding ICGFA quantification during colorectal surgery with a focus on impactful clinical deployment.

METHODS

A systematic review was performed of English language publications regarding clinical studies of ICGFA quantification in colorectal surgery in PubMed, Scopus, Web of Science and Cochrane Library on 29th August 2024, updated to 18th November 2024, following PRISMA guidelines. Newcastle Ottawa scale (NOS) was used to assess quality.

RESULTS

A total of 1428 studies were screened with 22 studies (1469 patients) selected. There was significant heterogeneity of ICGFA methodology, quantification methods and parameter selection and only three studies were NOS "high" quality. Extracorporeal application was most common. Four studies (154 patients) conducted real-time ICGFA analyses (others were post hoc) and four utilised artificial intelligence methods. Eleven studies only included patients undergoing left-sided resection (six focusing specifically on rectal resections). Only one study employed the quantification method to guide intra-operative decision-making regarding colonic transection. Twenty-six different perfusion parameters were assessed, with time from injection to visible fluorescence and maximum intensity the most commonly (but not only) correlated parameters regarding anastomotic complication (n = 18). Other grounding correlates were tissue oxygenation (n = 3, two with hyperspectral imagery), metabolites (n = 2) and surgeon interpretation (n = 5).

CONCLUSION

Quantification of the ICGFA signal for colorectal surgery is feasible but has so far seen limited academic advancement beyond feasibility.

Impact of indocyanine green fluorescence angiography on surgeon action and anastomotic leak in colorectal resections. A systematic review and meta-analysis

BACKGROUND

Indocyanine green fluorescence angiography (ICGFA) during colorectal surgery either reassures surgeons regarding intestinal perfusion sufficiency or prompts changed surgical strategy by indicating unsuspected insufficiency. This study describes existing evidence supporting ICGFA use in colorectal surgery, particularly regarding impact on intraoperative decisions.

METHODS

Searches were performed on PubMed, ScienceDirect, Scopus, Web of Science, Cochrane Collaboration databases on 5th December 2023, updated to 19th August 2024. Full English language publications of clinical studies in human patients undergoing colorectal resection with primary anastomosis with the use of ICGFA to assess bowel perfusion intraoperatively, with a control group, were included. Pooling of anastomotic leak (AL) rates was performed for primary outcome analysis with odds ratio (OR) and number-needed-to-treat (NNT) calculated regarding leak reduction.

RESULTS

45 studies comprising 14,333 patients were included, with 7 randomised controlled trials (2911 patients). Overall, AL rate was 6.8%, 4.5% with ICGFA and 8.5% without (OR:0.47, p < 0.001, NNT 23), increasing to 9.5%, 7.5% and 11.6%, respectively, in randomised controlled trials (OR:0.62, p < 0.01, NNT 25). In rectal resections, AL rate was 4.7% with ICGFA vs 11.5% without (OR: 0.38, p < 0.0001). 26 studies performed ICGFA before and after anastomosis formation and 19 used ICGFA only prior to bowel transection, with no significant difference of AL rate reduction on subgroup testing. ICGFA prompted a change in surgical plan in 8.4% of thirty-four studies reporting this. Interestingly, in these studies, leak rates overall were 3.7% when ICGFA matched surgeon judgement versus 5.7% when it prompted change (OR 0.51, p < 0.0025), versus 7.7% without (OR 0.45, p < 0.0001). In rectal resections, these figures were 5%, 8.8% (OR 0.42, p = 0.01) and 12.0% (OR0.39, p < 0.0001), respectively.

CONCLUSIONS

ICGFA colorectal perfusion assessment is associated with lower anastomotic leak rates, especially when confirming surgeons' judgement, and may so stratify patients post-operatively regarding subsequent anastomotic leak rate.

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.

Fluorescence angiography with indocyanine green for low anterior resection in patients with rectal cancer: a prospective before and after study

BACKGROUND

Inadequate bowel perfusion is among risk factors for colorectal anastomotic leaks. Perfusion can be assessed with indocyanine green fluorescence angiography (ICG) during colon resections. Possible benefits from its systematic use in high-risk patients with rectal cancer remain inconsistent. This study aimed to evaluate the surgical modifications induced by ICG assessment during rectal cancer surgery and associated anastomotic leaks.

METHODS

This prospective before and after cohort study was conducted in a single Canadian high-volume colorectal surgery center. Eligible patients were undergoing a low anterior resection for rectal cancer below 15 cm from the anal margin. Stapled and handsewn coloanal anastomoses were included. The experimental group was recruited prospectively, undergoing surgery using fluorescence angiography with ICG. The control group was built retrospectively from consecutive patients who had been operated on without ICG, prior to its implementation.

RESULTS

Each cohort included 113 patients. The use of ICG led to modifications from initial surgical plan in 10.6% of patients, with no occurrence of anastomotic leaks in this specific group. When comparing leak rates, using ICG seemed to be protective, but this could not be statistically proven, overall (13.3% vs. 6.2%, p = 0.07), nor for handsewn coloanal anastomoses (11.8% vs. 5.9%, p = 0.67). A lack of power could explain such non-significant results, especially with low overall anastomotic leak rates recorded.

CONCLUSION

ICG influenced ultimate proximal resection margin in a clinically relevant proportion of cases. It might be associated with reduced leak rates although not formally proven with this data. This technology is safe and easy to apply in high-volume colorectal centers.

Evaluation of the efficacy of natural orifice specimen extraction surgery versus conventional laparoscopic surgery for colorectal cancers: A systematic review and meta‐analysis

Aim

Natural orifice specimen extraction surgery (NOSES) has gained significant importance in treating cancers. The current study is a meta‐analysis that aimed to assess the short‐term efficacy and long‐term prognostic impact of NOSES and conventional laparoscopic (CL) surgery in the treatment of colorectal cancer (CRC).

Method

Published reports in several medical databases up to February 2024 were searched and information pertinent to outcomes of NOSES and CL in retrospective and randomized studies to treat CRC was collected. Pooled weighted/standardized mean difference (WMD/SMD), odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) were calculated using a fixed‐effects model or random‐effects model, and meta‐analysis was subsequently performed using Stata.

Results

Thirty‐one studies with a total of 4637 patients were included in this meta‐analysis. When compared with CL, NOSES had significant advantages in several indicators, such as wound infection [OR = 0.22 (95% CI 0.13–0.38); Z = 5.56, p = 0], incisional hernia [OR = 0.24 (95% CI 0.11–0.54); Z = 3.44, p = 0.001], blood loss [WMD = −10.17 (95% CI −14.75 to −5.60); Z = 4.36, p = 0], incision length [WMD = −4.94 (95% CI −5.27 to −4.60); Z = 29.10, p = 0.00], postoperative pain [WMD = −1.43 (95% CI −1.69 to −1.18); Z = 11.02, p = 0.00], use of additional analgesics [OR = 0.57 (95% CI 0.39–0.82); Z = 3.06, p = 0.002], hospital stay [WMD = –1.25 (95% CI −1.58 to –0.93); Z = 7.65, p = 0.00], gastrointestinal recovery [WMD = −13.42 (95% CI −17.77 to −9.07); Z = 6.05, p = 0.00], first flatus [WMD = −0.50 (95% CI −0.68 to −0.32); Z = 5.34, p = 0.00] and cosmetic result [WMD = 2.11 (95% CI 0.92–3.30); Z = 3.47, p = 0.001]. However, NOSES required a significantly longer duration of surgery [WMD = 14.13 (95% CI 6.70–21.56); Z = 3.73, p = 0.00]. There were no significant differences in postoperative anastomotic leakage, intra‐abdominal infection, lymph node harvest, proximal and distal margins, 5‐year disease‐free and 5‐year overall survival and pelvic floor function.

Conclusion

NOSES is considered an efficient surgical method of treatment for CRC that allows patients to have long‐term favourable oncological outcomes while recovering faster with minimal pain. However, these findings still require confirmation through studies on large population cohorts.

Efficacy and Safety of Fluorescence-Guided Surgery Compared to Conventional Surgery in the Management of Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

The use of fluorescence agents and imaging systems is a promising adjunct in the surgical management of colorectal cancer. This systematic review and meta-analysis aimed to assess the safety and efficacy of fluorescence-guided surgery in the management of colorectal cancer, with a comparison to conventional (non-fluorescence-guided) surgery.

METHODS

A literature search of MEDLINE, Embase, Emcare, and CINAHL databases was performed for studies that reported data on the outcomes of fluorescence-guided surgery, with or without a comparison group undergoing conventional surgery, for colorectal cancer between January 2000 and January 2024. A meta-analysis was performed using random-effect models, and between-study heterogeneity was assessed.

RESULTS

35 studies of 3217 patients with colorectal cancer were included: 26 studies (964 patients) reported on fluorescence-guided surgery and 9 studies (2253 patients) reported on fluorescence versus conventional surgery. The weighted mean of the cancer detection rate of fluorescence-guided surgery was 71% (95% CI 0.55-0.85), with no significant difference in lymph node yield ratio (WMD -0.04; 95% CI -0.10-0.02; p = 0.201) between fluorescence and conventional surgery groups. There was a significantly lower blood loss (WMD -4.38; 95% CI -7.05--1.70; p = 0.001) and complication rate (WMD -0.04; 95% CI -0.07-0.00; p = 0.027) in the fluorescence-guided surgery group, with a potentially lower anastomotic leak rate (WMD -0.05; 95% CI -0.10-0.01; p = 0.092).

CONCLUSIONS

Fluorescence-guided surgery is a safe and effective approach in the management of colorectal cancer, potentially reducing blood loss and complications. Further randomised controlled trials are required comparing fluorescence-guided surgery with conventional surgery to determine its prognostic benefit and where it should precisely fit within the management pathway of colorectal cancer.

Indocyanine green near-infrared fluorescence bowel perfusion assessment to prevent anastomotic leakage in minimally invasive colorectal surgery (AVOID): a multicentre, randomised, controlled, phase 3 trial

BACKGROUND

Anastomotic leakage is a severe postoperative complication in colorectal surgery and compromised bowel perfusion is considered a major contributing factor. Conventional methods to assess bowel perfusion have a low predictive value for anastomotic leakage. We therefore aimed to evaluate the efficacy of real-time assessment with near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) in the prevention of anastomotic leakage.

METHODS

This multicentre, randomised, controlled, phase 3 trial was done in eight hospitals in the Netherlands. We included adults (aged >18 years) who were scheduled for laparoscopic or robotic colorectal surgery (with planned primary anastomosis) for benign and malignant diseases. Preoperatively, patients were randomly assigned (1:1) to fluorescence-guided bowel anastomosis (FGBA) or conventional bowel anastomosis (CBA) by variable block randomisation (block sizes 4, 6, and 8) and stratified by site. The operating surgeon and investigators analysing the data were not masked to group assignment. Patients were unmasked after the surgical procedure or after study end. In the FGBA group, surgeons marked anastomosis levels per conventional perfusion assessment and then administered 5 mg of ICG by 2 mL intravenous bolus. They assessed bowel perfusion using NIR fluorescence imaging and adjusted (or kept) transection lines accordingly. Only conventional methods for bowel perfusion assessment were used in the CBA group. The primary outcome was the difference in the rate of clinically relevant anastomotic leakage (ie, requiring active therapeutic intervention but manageable without reoperation [grade B] or requiring reoperation [grade C], per the International Study Group of Rectal Cancer) between the FGBA group and the CBA group within 90 days post-surgery. The primary outcome and safety were assessed in the intention-to-treat population. This study was registered with ToetsingOnline.nl (NL7502) and ClinicalTrials.gov (NCT04712032) and is complete.

FINDINGS

Between July 2, 2020, and Feb 21, 2023, 982 patients were enrolled, of whom 490 were assigned to FGBA and 492 were assigned to CBA. After excluding 51 patients, the intention-to-treat population comprised 931 (463 assigned FGBA and 468 assigned CBA). Patients had a median age of 68·0 years (IQR 59·0-75·0) and 485 (52%) were male and 446 (48%) were female. Ethnicity data were not available. The overall 90-day rate of clinically relevant anastomotic leakage was not significantly different between the FGBA group (32 [7%] of 463 patients) and the CBA group (42 [9%] of 468 patients; relative risk 0·77 [95% CI 0·50-1·20]; p=0·24). No adverse events related to ICG use were observed. 313 serious adverse events in 229 (25%) patients were at 90-day follow-up (159 serious adverse events in 113 [24%] patients in the FGBA group and 154 serious adverse events in 116 [25%] patients in the CBA group). 18 (2%) people died by 90 days (ten in the FGBA group and eight in the CBA group).

INTERPRETATION

ICG NIR fluorescence imaging did not reduce 90-day anastomotic leakage rates in this trial across all types of colorectal surgeries. Further research should be done in subgroups, such as rectosigmoid resections, for which evidence suggests ICG NIR might be beneficial.

FUNDING

Olympus Medical, Diagnostic Green, and Intuitive Foundation.

The use of near-infrared angiography in evaluating bowel anastomosis during a gynecologic oncology surgery

Reducing anastomotic leak rates after bowel resection is a priority among patients undergoing gynecologic oncology surgery. While near-infrared (NIR) angiography has been investigated in the colorectal literature, more recent work has demonstrated promising results when used in gynecologic cancer surgery. It has been repeatedly shown to be a safe intervention that can offer real time assessment of bowel perfusion, offering the surgeon the opportunity to act on the results in the hopes of decreasing the risk of complications.

The use of indocyanine green for colorectal anastomoses: a systematic review and meta-analysis

INTRODUCTION

Anastomotic leak is a relatively common and debilitating complication. Colorectal leak rates vary widely in the literature, ranging from 1% to 20%. In modern surgical practice, there is much emphasis on the use of indocyanine green (ICG). This is a fluorescent dye administered intravenously to locate and predict an adequate line of anastomosis. We sought to analyse the current literature and supporting evidence behind the use of ICG in the context of elective colorectal surgery.

METHODS

A literature search was conducted for papers published between January 1991 and December 2022 concerning the use of ICG in colorectal surgery. Data on anastomotic leak, overall complication rate, operative time and involvement of artificial intelligence (AI) were compared.

RESULTS

A total of 24 studies were selected, including 3 randomised controlled trials. There was an anastomotic leak rate of 4.3% in cases with ICG administration compared with 9.5% in the control group (p<0.00001). Seven studies mentioned overall complication rates. These were lower in the ICG cohort than in the control group (15.5% vs 24.5%). There was no significant correlation between ICG use and operative time (p=0.78). Five studies looked at AI, with results suggesting that use of AI leads to much better accuracy in ICG metric analysis. However, the current literature is still inconclusive.

CONCLUSIONS

While there is strong evidence behind ICG use in the existing literature, more randomised controlled trials are required for better recommendations. AI in ICG metric interpretation has proved to be difficult owing to interpatient variability. Nevertheless, new data suggest better understanding and standardisation.

Blood perfusion assessment by near-infrared fluorescence angiography of epiploic appendages in prevention of anastomotic leakage after laparoscopic intersphincteric resection for ultra-low rectal cancer: a case-matched study

BACKGROUND

The role of intraoperative near-infrared fluorescence angiography with indocyanine green in reducing anastomotic leakage (AL) has been demonstrated in colorectal surgery, however, its perfusion assessment mode, and efficacy in reducing anastomotic leakage after laparoscopic intersphincteric resection (LsISR) need to be further elucidated.

AIM

Aim was to study near-infrared fluorescent angiography to help identify bowel ischemia to reduce AL after LsISR.

MATERIAL AND METHODS

A retrospective case-matched study was conducted in one referral center. A total of 556 consecutive patients with ultra-low rectal cancer including 140 patients with fluorescence angiography of epiploic appendages (FAEA)were enrolled. Perfusion assessment by FAEA in the monochrome fluorescence mode. Patients were divided into two groups based on perfusion assessment by FAEA. The primary endpoint was the AL rate within 6 months, and the secondary endpoint was the structural sequelae of anastomotic leakage (SSAL).

RESULTS

After matching, the study group (n = 109) and control group (n = 190) were well-balanced. The AL rate in the FAEA group was lower before (3.6% vs. 10.1%, P = 0.026) and after matching (3.7% vs. 10.5%, P = 0.036). Propensity scores matching analysis (OR 0.275, 95% CI 0.035-0.937, P 0.039), inverse probability of treatment weighting (OR 0.814, 95% CI 0.765-0.921, P 0.002), and regression analysis (OR 0.298, 95% CI 0.112-0.790, P = 0.015), showed that FAEA was an independent protector factor for AL. This technique can significantly shorten postoperative hospital stay [9 (6-13) vs. 10 (8-13), P = 0.024] and reduce the risk of SSAL (1.4% vs. 6.0%, P = 0.029).

CONCLUSIONS

Perfusion assessment by FAEA can achieve better visualization in LsISR and reduce the incidence of AL, subsequently avoiding SSAL after LsISR.

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.

C-reactive protein-to-albumin ratio as a risk factor for anastomotic leakage after anterior resection for rectal cancer with intraoperative use of indocyanine green fluorescence imaging

INTRODUCTION

Indocyanine green fluorescence imaging (ICG-FI) reduces anastomotic leakage (AL) in rectal cancer surgery. However, no studies investigating risk factors for anastomotic leakage specific to the group using ICG-FI have ever previously been conducted. The purpose of this retrospective multicenter study was to ascertain the risk factors for AL in the group using ICG-FI.

METHODS

A total of 638 patients who underwent laparoscopic or robotic anterior resection for rectal cancer between April 2018 and March 2023 were included in this study. Patients were divided into two groups: the ICG-FI group (n = 269) and the non-ICG-FI group (n = 369) for comparative analysis. The effects of clinicopathological and treatment-related factors on AL in the ICG-FI group were evaluated using both univariate and multivariate analyses.

RESULTS

The incidence of AL in the ICG-FI group was 4.8%. Although there was no significant difference in the incidence of AL between the two groups, it was observed to be lower in the ICG-FI group. A multivariate analysis revealed a preoperative C-reactive protein-to-albumin ratio (CAR) ≥ 0.049 (odds ratio, 3.73; 95% confidence interval, 1.01-13.70; p = 0.048) as an independent risk factor for AL in the ICG-FI group.

CONCLUSIONS

In this study, CAR was the only identified risk factor for AL in the ICG-FI group. It was suggested that CAR could be a criterion for early surgical intervention, prior to the escalation of risks, or for considering interventions such as diverting stoma creation.

ARIA II: a randomized controlled trial of near-infrared Angiography during RectosIgmoid resection and Anastomosis in women with ovarian cancer

BACKGROUND

Ovarian cancer with extensive metastatic disease involving pelvic structures often requires rectosigmoid resection for complete gross resection; however, it is associated with increased surgical morbidity. There are limited data, and none in ovarian cancer, on near-infrared assessment of perfusion in rectosigmoid resections with anastomosis.

PRIMARY OBJECTIVE

To compare the rate of pelvic complications (pelvic abscesses, anastomotic leaks, and infections) within 30 days of surgery with and without near-infrared assessment of perfusion at time of rectosigmoid resection and re-anastomosis in patients undergoing cytoreductive surgery for ovarian cancer.

STUDY HYPOTHESIS

We hypothesize the use of near-infrared technology (intravenous indocyanine green and endoscopic near-infrared fluorescence imaging), compared with standard intra-operative assessment, to evaluate anastomotic perfusion at time of rectosigmoid resection and re-anastomosis will result in lower rates of post-operative pelvic complications.

TRIAL DESIGN

This is a planned multicenter randomized controlled trial. Patients who undergo rectosigmoid resection as part of their ovarian cytoreductive surgery will be randomized 1:1 to standard assessment of anastomosis with the surgeon's usual technique (control arm) or assessment with near-infrared angiography using indocyanine green and endoscopic fluorescence imaging (experimental arm). Randomization will occur after rectosigmoid resection has been completed and the surgeon declares their plan to create a diverting ostomy. Randomization will be stratified by plan for diverting ostomy.

MAJOR INCLUSION/EXCLUSION CRITERIA

Main inclusion criteria include patients with primary or recurrent ovarian, fallopian tube, or primary peritoneal cancer who are scheduled for cytoreductive surgery with suspected need for low-anterior rectosigmoid resection.

PRIMARY ENDPOINT

Rate of 30-day post-operative pelvic complications.

SAMPLE SIZE

310 (155 per arm) ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS: Q2 2027 and Q4 2027, respectively.

TRIAL REGISTRATION

NCT04878094.

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.

Indocyanine green fluorescence angiography in colorectal surgery: A retrospective case-control analysis in Mexico

INTRODUCTION AND AIMS

An anastomotic leak is one of the most dreaded complications in colorectal surgery because it increases postoperative morbidity and mortality. The aim of the present study was to identify whether indocyanine green fluorescence angiography (ICGFA) reduced the anastomotic dehiscence rate in colorectal surgery.

MATERIAL AND METHODS

A retrospective study on patients that underwent colorectal surgery with colonic resection or low anterior resection and primary anastomosis, within the time frame of January 2019 and September 2021, was conducted. The patients were divided into the case group, in which ICGFA was performed for the intraoperative evaluation of blood perfusion at the anastomosis site, and the control group, in which ICGFA was not utilized.

RESULTS

A total of 168 medical records were reviewed, resulting in 83 cases and 85 controls. Inadequate perfusion that required changing the surgical site of the anastomosis was identified in 4.8% of the case group (n = 4). A trend toward reducing the leak rate with ICGFA was identified (6% [n = 5] in the cases vs 7.1% in the controls [n = 6] [p = 0.999]). The patients that underwent anastomosis site change due to inadequate perfusion had a 0% leak rate.

CONCLUSIONS

ICGFA as a method to evaluate intraoperative blood perfusion showed a trend toward reducing the incidence of anastomotic leak in colorectal surgery.

Indocyanine green: The guide to safer and more effective surgery

In this editorial we comment on the article by Kalayarasan and co-workers published in the recent issue of the World Journal of Gastrointestinal Surgery. The authors present an interesting review on the use of indocyanine green fluorescence in different aspects of abdominal surgery. They also highlight future perspectives of the use of indocyanine green in mini-invasive surgery. Indocyanine green, used for fluorescence imaging, has been approved by the Food and Drug Administration and is safe for use in humans. It can be administered intravenously or intra-arterially. Since its advent, there have been several advancements in the applications of indocyanine green, especially in the surgical field, such as intraoperative mapping and biopsy of sentinel lymph node, measurement of hepatic function prior to resection, in neurosurgical cases to detect vascular anomalies, in cardiovascular cases for patency and assessment of vascular abnormalities, in predicting healing following amputations, in helping visualization of hepatobiliary anatomy and blood vessels, in reconstructive surgery, to assess flap viability and for the evaluation of tissue perfusion following major trauma and burns. For these reasons, the intraoperative use of indocyanine green has become common in a variety of surgical specialties and transplant surgery. Colorectal surgery has just lately begun to adopt this technique, particularly for perfusion visualization to prevent anastomotic leakage. The regular use of indocyanine green coupled with fluorescence angiography has recently been proposed as a feasible tool to help improve patient outcomes. Using the best available data, it has been shown that routine use of indocyanine green in colorectal surgery reduces the rates of anastomotic leak. The use of indocyanine green is proven to be safe, feasible, and effective in both elective and emergency scenarios. However, additional robust evidence from larger-scale, high-quality studies is essential before incorporating indocyanine green guided surgery into standard practice.

Indocyanine green (ICG) fluorescence-enhanced applications in pediatric surgery

The breadth of pediatric surgical practice and variety of anatomic anomalies that characterize surgical disease in children and neonates require a unique level of operative mastery and versatility. Intraoperative navigation of small, complex, and often abnormal anatomy presents a particular challenge for pediatric surgeons. Clinical experience with fluorescent tissue dye, specifically indocyanine green (ICG), is quickly gaining widespread incorporation into adult surgical practice as a safe, non-toxic means of accurately visualizing tissue perfusion, lymphatic flow, and biliary anatomy to enhance operative speed, safety, and patient outcomes. Experience in pediatric surgery, however, remains limited. ICG-fluorescence guided surgery is poised to address the challenges of pediatric and neonatal operations for a growing breadth of surgical pathology. Fluorescent angiography has permitted intraoperative visualization of colorectal flap perfusion for complex pelvic reconstruction and anastomotic perfusion after esophageal atresia repair, while its hepatic absorption and biliary excretion has made it an excellent agent for delineating the dissection plane in the Kasai portoenterostomy and identifying both primary and metastatic hepatoblastoma lesions. Subcutaneous and intra-lymphatic ICG injection can identify iatrogenic chylous leaks and improved yields in sentinel lymph node biopsies. ICG-guided surgery holds promise for more widespread use in pediatric surgical conditions, and continued evaluation of efficacy will be necessary to better inform clinical practice and identify where to focus and develop this technical resource.

Consensus conference statement on fluorescence-guided surgery (FGS) ESSO course on fluorescence-guided surgery

BACKGROUND

Fluorescence-guided surgery (FGS) has emerged as an innovative technique with promising applications in various surgical specialties. However, clinical implementation is hampered by limited availability of evidence-based reference work supporting the translation towards standard-of-care use in surgical practice. Therefore, we developed a consensus statement on current applications of FGS.

METHODS

During an international FGS course, participants anonymously voted on 36 statements. Consensus was defined as agreement ≥70% with participation grade of ≥80%. All participants of the questionnaire were stratified for user and handling experience within five domains of applicability (lymphatics & lymph node imaging; tissue perfusion; biliary anatomy and urinary tracts; tumor imaging in colorectal, HPB, and endocrine surgery, and quantification and (tumor-) targeted imaging). Results were pooled to determine consensus for each statement within the respective sections based on the degree of agreement.

RESULTS

In total 43/52 (81%) course participants were eligible as voting members for consensus, comprising the expert panel (n = 12) and trained users (n = 31). Consensus was achieved in 17 out of 36 (45%) statements with highest level of agreement for application of FGS in tissue perfusion and biliary/urinary tract visualization (71% and 67%, respectively) and lowest within the tumor imaging section (0%).

CONCLUSIONS

FGS is currently established for tissue perfusion and vital structure imaging. Lymphatics & lymph node imaging in breast cancer and melanoma are evolving, and tumor tissue imaging holds promise in early-phase trials. Quantification and (tumor-)targeted imaging are advancing toward clinical validation. Additional research is needed for tumor imaging due to a lack of consensus.

Current status of indocyanine green fluorescent angiography in assessing perfusion of gastric conduit and oesophago-gastric anastomosis

Anastomotic leak (AL) remains a significant complication after esophagectomy. Indocyanine green fluorescent angiography (ICG-FA) is a promising and safe technique for assessing gastric conduit (GC) perfusion intraoperatively. It provides detailed visualization of tissue perfusion and has demonstrated usefulness in oesophageal surgery. GC perfusion analysis by ICG-FA is crucial in constructing the conduit and selecting the anastomotic site and enables surgeons to make necessary adjustments during surgery to potentially reduce ALs. However, anastomotic integrity involves multiple factors, and ICG-FA must be combined with optimization of patient and procedural factors to decrease AL rates. This review summarizes ICG-FA's current applications in assessing esophago-gastric anastomosis perfusion, including qualitative and quantitative analysis and different imaging systems. It also explores how fluorescent imaging could decrease ALs and aid clinicians in utilizing ICG-FA to improve esophagectomy outcomes.

Applications of indocyanine greenenhanced fluorescence in the laparoscopic treatment of colonic stricture after necrotizing enterocolitis

BACKGROUND

The status of anastomotic blood perfusion is associated with the occurrence of anastomotic leakage after intestinal anastomosis. Fluorescence angiography (FA) with indocyanine green (ICG) can objectively assess intestinal blood perfusion. This study aims to investigate whether anastomotic perfusion assessment with ICG influences surgical decision-making during laparoscopic intestinal resection and primary anastomosis for colonic stricture after necrotizing enterocolitis.

METHODS

Patients who underwent laparoscopic intestinal resection and primary anastomosis between January 2022 and December 2022 were retrospectively analyzed. Before intestinal anastomosis, the ICG fluorescence technology was used to evaluate the blood perfusion of intestinal tubes on both sides of the anastomosis. After the completion of primary anastomosis, the anastomotic blood perfusion was assessed again.

RESULTS

Of the 13 cases, laparoscopy was used to determine the extent of the diseased bowel to be excised, and the normal bowel was preserved for anastomosis. The anastomosis was established under the guidance of ICG fluorescence technology, and FA was performed after anastomosis to confirm good blood flow in the proximal bowel. The anastomotic intestinal tube was changed in one case because FA showed a difference between the normal range of intestinal blood flow and the macroscopic prediction. There was no evidence of ICG allergy, anastomotic leakage, anastomotic stricture, or other complications. The median follow-up was 6 months, and all patients recovered well.

CONCLUSIONS

The ICG fluorescence technology is helpful in precisely and efficiently determining the anastomotic intestinal blood flow during stricture resection and in avoiding anastomotic leakage caused by poor anastomotic intestinal blood flow to some extent, with satisfactory short-term efficacy.

The value of ICG-guided left colon vascular variation and anatomical rules for the radical resection of proctosigmoid colon cancer

Objective

During laparoscopic radical resection for proctosigmoid colon cancer (PCC), surgeons could inadvertently damage the arteries when following the operation path.This study investigated the variations in left colon blood vessels in order to guide the scientific protection of the marginal artery (MA) during laparoscopic surgery for PCC.

Methods

Data from seven patients who underwent inferior mesenteric artery (IMA) angiography were included as imaging references to preliminarily explore the vascular structure and variation in the left colon. The clinical video data of 183 PCC patients were retrospectively analyzed to observe intraoperative MA injury. Meanwhile, a prospective cohort of 96 patients with the same disease underwent intraoperative indocyanine green (ICG) fluorescence imaging of the peripheral sigmoid artery network, the variation of marginal arteries was summarized, and the distance between vessels and the bowel was measured at different levels. Patients were divided into 'ICG group' and 'non-ICG group' according to whether ICG guidance was performed, and perioperative conditions were compared between the two groups. Taking the integrity of lymph node dissection into consideration, 18 patients underwent carbon nanonode tracing. This study was conducted under the standard consent and ethical approval of the Ethics Committee of our center.

Results

7 patients with IMA angiography shared some vascular structures, defined as 'Dangerous Triangle' and 'Secure Window'. Through intraoperative observation, the primary arch was typically located 4.2 (2.3-6.0) cm away from the intestinal canal, and 5.21% (5/96) patients had poor anastomosis at the primary arch. Moreover, secondary vascular arches (6.4 (4.6-10.0) cm from the intestinal wall) were observed in 38.54% of patients. MA injury was identified in 2 of 183 cases, and the ischemic bowel was timely dissected, whereas no such injury occurred during ICG fluorescenceguided surgery. Guided by carbon nanoparticles, the integrity of lymph node dissection can be maintained while preserving the secondary arch in all patients.

Conclusions

This study demonstrated the benefits of ICG guidance in protecting the intestinal blood supply in laparoscopic PCC surgery. By enhancing the understanding of primary and secondary vascular arches, secure windows, and dangerous triangles, surgeons can safely optimize the surgical path during surgery.

Blood Perfusion Assessment by Indocyanine Green Fluorescence Imaging for Minimally Invasive Rectal Cancer Surgery (EssentiAL trial): A Randomized Clinical Trial

OBJECTIVE

The aim of the present randomized controlled trial was to evaluate the superiority of indocyanine green fluorescence imaging (ICG-FI) in reducing the rate of anastomotic leakage in minimally invasive rectal cancer surgery.

BACKGROUND

The role of ICG-FI in anastomotic leakage in minimally invasive rectal cancer surgery is controversial according to the published literature.

METHODS

This randomized, open-label, phase 3, trial was performed at 41 hospitals in Japan. Patients with clinically stage 0-III rectal carcinoma less than 12 cm from the anal verge, scheduled for minimally invasive sphincter-preserving surgery were preoperatively randomly assigned to receive a blood flow evaluation by ICG-FI (ICG+ group) or no blood flow evaluation by ICG-FI (ICG- group). The primary endpoint was the anastomotic leakage rate (grade A+B+C, expected reduction rate of 6%) analyzed in the modified intention-to-treat population.

RESULTS

Between December 2018 and February 2021, a total of 850 patients were enrolled and randomized. After the exclusion of 11 patients, 839 were subject to the modified intention-to-treat population (422 in the ICG+ group and 417 in the ICG- group). The rate of anastomotic leakage (grade A+B+C) was significantly lower in the ICG+ group (7.6%) than in the ICG- group (11.8%) (relative risk, 0.645; 95% confidence interval 0.422-0.987; P =0.041). The rate of anastomotic leakage (grade B+C) was 4.7% in the ICG+ group and 8.2% in the ICG- group ( P =0.044), and the respective reoperation rates were 0.5% and 2.4% ( P =0.021).

CONCLUSIONS

Although the actual reduction rate of anastomotic leakage in the ICG+ group was lower than the expected reduction rate and ICG-FI was not superior to white light, ICG-FI significantly reduced the anastomotic leakage rate by 4.2%.

Time required for indocyanine green fluorescence emission for evaluating bowel perfusion in left-sided colon and rectal cancer surgery

BACKGROUND

Indocyanine green fluorescence imaging (ICG-FI) has been reported to be useful in reducing the incidence of anastomotic leakage (AL) in colectomy. This study aimed to investigate the correlation between the required time for ICG fluorescence emission and AL in left-sided colon and rectal cancer surgery using the double-stapling technique (DST) anastomosis.

METHODS

This retrospective study included 217 patients with colorectal cancer who underwent left-sided colon and rectal surgery using ICG-FI-based perfusion assessment at our department between November 2018 and July 2022. We recorded the time required to achieve maximum fluorescence emission after ICG systemic injection and assessed its correlation with the occurrence of AL.

RESULTS

Among 217 patients, AL occurred in 21 patients (9.7%). The median time from ICG administration to maximum fluorescence emission was 32 s (range 25-58 s) in the AL group and 28 s (range 10-45 s) in the non-AL group (p < 0.001). The cut-off value for the presence of AL obtained from the ROC curve was 31 s. In 58 patients with a required time for ICG fluorescence of 31 s or longer, the following risk factors for AL were identified: low preoperative albumin [3.4 mg/dl (range 2.6-4.4) vs. 3.9 mg/dl (range 2.6-4.9), p = 0.016], absence of preoperative mechanical bowel preparation (53.8% vs. 91.1%, p = 0.005), obstructive tumor (61.5% vs. 17.8%, p = 0.004), and larger tumor diameter [65 mm (range 40-90) vs. 35 mm (range 4.0-100), p < 0.001].

CONCLUSION

The time required for ICG fluorescence emission was associated with AL.

Indocyanine green dye and its application in gastrointestinal surgery: The future is bright green

Indocyanine green (ICG) is a water-soluble fluorescent dye that is minimally toxic and widely used in gastrointestinal surgery. ICG facilitates anatomical identification of structures (e.g., ureters), assessment of lymph nodes, biliary mapping, organ perfusion and anastomosis assessment, and aids in determining the adequacy of oncological margins. In addition, ICG can be conjugated to artificially created antibodies for tumour markers, such as carcinoembryonic antigen for colorectal, breast, lung, and gastric cancer, prostate-specific antigen for prostate cancer, and cancer antigen 125 for ovarian cancer. Although ICG has shown promising results, the optimization of patient factors, dye factors, equipment, and the method of assessing fluorescence intensity could further enhance its utility. This review summarizes the clinical application of ICG in gastrointestinal surgery and discusses the emergence of novel dyes such as ZW-800 and VM678 that have demonstrated appropriate pharmacokinetic properties and improved target-to-background ratios in animal studies. With the emergence of robotic technology and the increasing reporting of ICG utility, a comprehensive review of clinical application of ICG in gastrointestinal surgery is timely and this review serves that aim.

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.

Fluorescent Imaging in Visceral Surgery: Current Opportunities and Future Perspectives

Background

Fluorescent imaging using indocyanine green (FI-ICG) has become quite popular in the past century, giving the surgeon various pre- and intraoperative approaches in visceral surgery. Nevertheless, several aspects and pitfalls of using the technology need to be addressed.

Summary

This article focused on the applications of FI-ICG in esophageal and colorectal surgery as this is where the clinical relevance is most important. Important benchmark studies were summarized to explain the background. In addition, dosage, the timing of application, and future perspectives - especially quantification methods - were the article's content.

Key Message

There are currently encouraging data on the use of FI-ICG, particularly concerning perfusion assessment to reduce anastomotic leakage, although its use is mainly subjective. The optimal dosage remains unclear; for perfusion evaluation, it should be around 0.1 mg/kg body weight. Moreover, the quantification of FI-ICG opens new possibilities, so that reference values may be available in the future. However, in addition to perfusion measurement, the detection of additional hepatic lesions such as liver metastases or lesions of peritoneal carcinomatosis is also possible. A standardization of FI-ICG and further studies are needed to fully utilize FI-ICG.

Application of indocyanine green in surgery: A review of current evidence and implementation in trauma patients

Background: Modern surgical medicine strives to manage trauma while improving outcomes using functional imaging. Identification of viable tissues is crucial for the surgical management of polytrauma and burn patients presenting with soft tissue and hollow viscus injuries. Bowel anastomosis after trauma-related resection is associated with a high rate of leakage. The ability of the surgeon’s bare eye to determine bowel viability remains limited, and the need for a more standardized objective assessment has not yet been fulfilled. Hence, there is a need for more precise diagnostic tools to enhance surgical evaluation and visualization to aid early diagnosis and timely management to minimize trauma-associated complications. Indocyanine green (ICG) coupled with fluorescence angiography is a potential solution for this problem. ICG is a fluorescent dye that responds to near-infrared irradiation. Methods: We conducted a narrative review to address the utility of ICG in the surgical management of patients with trauma as well as elective surgery. Discussion: ICG has many applications in different medical fields and has recently become an important clinical indicator for surgical guidance. However, there is a paucity of information regarding the use of this technology to treat traumas. Recently, angiography with ICG has been introduced in clinical practice to visualize and quantify organ perfusion under several conditions, leading to fewer cases of anastomotic insufficiency. This has great potential to bridge this gap and enhance the clinical outcomes of surgery and patient safety. However, there is no consensus on the ideal dose, time, and manner of administration nor the indications that ICG provides a genuine advantage through greater safety in trauma surgical settings. Conclusions: There is a scarcity of publications describing the use of ICG in trauma patients as a potentially useful strategy to facilitate intraoperative decisions and to limit the extent of surgical resection. This review will improve our understanding of the utility of intraoperative ICG fluorescence in guiding and assisting trauma surgeons to deal with the intraoperative challenges and thus improve the patients’ operative care and safety in the field of trauma surgery.

Real-time semi-quantitative assessment of anastomotic blood perfusion in mini‑invasive rectal resections by Sidestream Dark Field (SDF) imaging technology: a prospective in vivo pilot study

PURPOSE

Anastomotic leakage (AL) is one of the severe complications after rectal surgery, and anastomotic ischemia is one of the main factors. This prospective in vivo pilot study aimed to evaluate the effectiveness of Sidestream Dark Field (SDF) imaging in quantitative assessment of anastomotic microcirculation and to analyze its correlation with AL.

METHODS

Thirty-three patients with rectal cancer who underwent laparoscopic low anterior resection from 2019 to 2020 were enrolled. Microcirculation was measured by SDF imaging at the descending colon, the mesocolon transection line (MTL), and 1 cm and 2 cm distal to the MTL. Anastomotic microcirculation was measured at the stapler anvil edge before anastomosis. Quantitative perfusion-related parameters were as follows: microcirculation flow index (MFI), perfused vessel density (PVD), proportion of perfused vessels (PPV), and total vessel density (TVD).

RESULTS

All patients obtained stable microcirculation images. Functional microcirculation parameters (MFI, PPV, PVD) decreased successively from the descending colon, the colon at MTL, and 1 cm and 2 cm distal to the MTL (all P < 0.01). Extremely poor microcirculation was found at the intestinal segment 2 cm distal to the MTL. Micro-perfusion was significantly lower at the colonic limb of the anastomosis compared with the descending colon (all P < 0.001). Anastomotic leakage occurred in 3 patients (9.1%) whose anastomotic microcirculation was significantly lower than those without AL (all P < 0.01). Blood perfusion at the colonic limb of the anastomosis was significantly higher in patients with left colic artery preservation than in controls.

CONCLUSION

SDF imaging is a promising technique for evaluating anastomotic microcirculation and has potential clinical significance for risk stratification of AL.

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.

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

Near-infrared fluorescence (NIRF) image-guided surgery is a useful tool that can help reduce perioperative complications and improve tissue recognition. Indocyanine green (ICG) dye is the most frequently used in clinical studies. ICG NIRF imaging has been used for lymph node identification. However, there are still many challenges in lymph node identification by ICG. There is increasing evidence that methylene blue (MB), another clinically applicable fluorescent dye, can also be useful in the intraoperative fluorescence-guided identification of structures and tissues. We hypothesized that MB NIRF imaging could be used for lymph node identification. The aim of this study was to evaluate the feasibility of intraoperative lymph node fluorescence detection using intravenously (IV) administered MB and compare it to ICG via a camera that has two dedicated near-infrared (NIR) channels. Three pigs were used in this study. ICG (0.2 mg/kg) was administered via a peripheral venous catheter followed by immediate administration of MB (0.25 mg/kg). NIRF images were acquired as video recordings at different time points (every 10 min) over an hour using the QUEST SPECTRUM® 3 system (Quest Medical Imaging, Middenmeer, The Netherlands), which has two dedicated NIR channels for simultaneous intraoperative fluorescence guidance. The 800 nm channel was used to capture ICG fluorescence and the 700 nm channel was used for MB. The target (lymph nodes and small bowel) and the background (vessels-free field of the mesentery) were highlighted as the regions of interest (ROIs), and corresponding fluorescence intensities (FI) from these ROIs were measured. The target-to-background ratio (TBR) was then computed as the mean FI of the target minus the mean FI of the background divided by the mean FI of the background. In all included animals, a clear identification of lymph nodes was achieved at all time points. The mean TBR of ICG in lymph nodes and small bowel was 4.57 ± 1.00 and 4.37 ± 1.70, respectively for the overall experimental time. Regarding MB, the mean TBR in lymph nodes and small bowel was 4.60 ± 0.92 and 3.27 ± 0.62, respectively. The Mann-Whitney U test of the lymph node TBR/small bowel TBR showed that the TBR ratio of MB was statistically significantly higher than ICG. The fluorescence optical imaging technology used allows for double-wavelength assessment. This feasibility study proves that lymph nodes can be discriminated using two different fluorophores (MB and ICG) with different wavelengths. The results suggest that MB has a promising potential to be used to detect lymphatic tissue during image-guided surgery. Further preclinical trials are needed before clinical translation.

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.

Techniques for Diagnosing Anastomotic Leaks Intraoperatively in Colorectal Surgeries: A Review

Colorectal cancer is one of the most common surgically curable malignancies worldwide, having a good prognosis even with liver metastasis. This improved patient outcome is marred by anastomotic leaks (AL) in operated patients of colorectal cancer despite a microscopically margin-negative resection (R0). Various risk factors have been attributed to causing this. Preoperative non-modifiable factors are age, male sex, cancer cachexia, and neoadjuvant chemo-radiotherapy, and modifiable factors are comorbidities, peripheral vascular disease, anemia, and malnutrition. Intraoperative risk factors include intraoperative surgical duration, blood loss and transfusions, fluid management, oxygen saturation, surgical technique (stapled, handsewn, or compression devices), and approach (open, laparoscopic, or robotic). Postoperative factors like anemia, infection, fluid management, and blood transfusions also have an effect. With the advent of enhanced recovery after surgery (ERAS) protocols, many modifiable factors can be optimized to reduce the risk. Prevention is better than cure as the morbidity and mortality of AL are very high. There is still a need for an intraoperative technique to detect the viability of anastomotic ends to predict and prevent AL. Prompt diagnosis of an AL is the key. Many surgeons have proposed using methods like air leak tests, intraoperative endoscopy, Doppler ultrasound, and near-infrared fluorescence imaging to decrease the incidence of AL. All these methods can minimize AL, resulting in significant intraoperative alterations to surgical tactics. This narrative review covers the methods of assessing of integrity of anastomosis during the surgery, which can help prevent anastomotic leakage.

[ICG angiography in prevention of colorectal anastomotic leakage]

OBJECTIVE

To evaluate the effectiveness of indocyanine green fluorescence angiography in assessment of colorectal anastomosis perfusion.

MATERIAL AND METHODS

A prospective single-center non-randomized comparative study included 85 patients with rectum and sigmoid colon cancer between September 2019 and March 2023. In the main group (n=41), we intraoperatively injected indocyanine green (ICG) IV to assess perfusion in the near infrared spectrum. In the control group (n=44), the same interventions were performed without ICG.

RESULTS

In the main group, anterior resection of the rectum was performed in 23 (56.1%) patients with neoplasms of distal sigmoid colon and rectosigmoid tumors. Low anterior resection was performed in 18 (43.9%) cases. In the control group, the same procedures were carried out in 24 (54.5%) and 20 (45.5%) patients, respectively. After mobilization of the colon and ICG injection, we corrected resection line in 4 cases. As soon as anastomosis was formed and blood supply was controlled by ICG fluorescence angiography, we performed a water-bubble test to detect anastomotic leakage. Positive tests were detected in 4 (9.8%) and 5 (11.4%) patients of both groups, respectively. Postoperative complications occurred in 10 (24.4%) and 11 (27.3%) patients, respectively (p=0.94). Anastomosis failure was found in 1 and 7 patients, respectively. Anastomotic leakage grade «B» was significantly more common in the control group (2.4 and 13.6%, respectively, p=0.06). Anastomotic leaks were absent in all 4 patients who underwent resection level adjustment after intraoperative ICG angiography.

CONCLUSION

Fluorescent luminescence will qualitatively improve intraoperative diagnosis of hypoperfusion of resection edges. Undoubtedly, this will reduce the incidence of colorectal anastomotic leaks caused by ischemia of large bowel wall.

[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.

Indocyanine green fluorescence imaging during laparoscopic rectal cancer surgery could reduce the incidence of anastomotic leakage: a single institutional retrospective cohort study

BACKGROUND

There is insufficient evidence on whether indocyanine green (ICG) fluorescence angiography can reduce the incidence of anastomotic leakage (AL). This retrospective cohort study aimed to evaluate the effect of ICG fluorescence angiography on AL rates in laparoscopic rectal cancer surgery at a single institution.

METHODS

Patients who underwent laparoscopic low anterior resection or intersphincteric resection with ICG fluorescence angiography (ICG group; n = 73) and patients who underwent a similar surgical procedure for rectal cancer without ICG fluorescence (non-ICG group; n = 114) were enrolled consecutively in this study. ICG fluorescence angiography was performed prior to transection of the proximal colon, and anastomosis was performed with sufficient perfusion using ICG fluorescence imaging. AL incidence was compared between both groups, and the risk factors for AL were analyzed.

RESULTS

AL occurred in 3 (4.1%) and 14 (12.3%) patients in the ICG and non-ICG groups, respectively. In the ICG group, the median perfusion time from ICG injection was 34 s, and 5 patients (6.8%) required revision of the proximal transection line. None of the patients requiring revision of the proximal transection line developed AL. In univariate analysis, longer operating time (odds ratio: 2.758; 95% confidence interval: 1.023-7.624) and no implementation of ICG fluorescence angiography (odds ratio: 3.266; 95% confidence interval: 1.038-11.793) were significant factors associated with AL incidence, although the creation of a diverting stoma or insertion of a transanal tube was insignificant.

CONCLUSION

ICG fluorescence angiography was associated with a significant reduction in AL during laparoscopic rectal cancer surgery. Changes in the surgical plan due to ICG fluorescence visibility may help improve the short-term outcomes of patients with rectal cancer.

The Colorectal Anastomosis: A Timeless Challenge

Colorectal anastomosis is a sophisticated problem that demands an elaborate discussion and an elegant solution. "Those who forget the past are condemned to repeat it." George Santayana, Life of Reason , 1905.

A Narrative Review of the Usefulness of Indocyanine Green Fluorescence Angiography for Perfusion Assessment in Colorectal Surgery

Anastomotic leakage is one of the most dreaded complications of colorectal surgery and is strongly associated with tissue perfusion. Indocyanine green fluorescence angiography (ICG-FA) using indocyanine green and near-infrared systems is an innovative technique that allows the visualization of anastomotic perfusion. Based on this information on tissue perfusion status, surgeons will be able to clearly identify colorectal segments with good blood flow for safer colorectal anastomosis. The results of several clinical trials indicate that ICG-FA may reduce the risk of AL in colorectal resection; however, the level of evidence is not high, as several other studies have failed to demonstrate a reduction in the risk of AL. Several large-scale RCTs are currently underway, and their results will determine whether ICG-FA is, indeed, useful. The major limitation of the current ICG-FA evaluation method, however, is that it is subjective and based on visual assessment by the surgeon. To complement this, the utility of objective evaluation methods for fluorescence using quantitative parameters is being investigated. Promising results have been reported from several clinical trials, but all trials are preliminary owing to their small sample size and lack of standardized protocols for quantitative evaluation. Therefore, appropriately standardized, high-quality, large-scale studies are warranted.

Novel surgical procedure for preventing anastomotic leakage following colorectal cancer surgery: A propensity score matching study

Hypoperfusion is the main cause of anastomotic leakage (AL) following colorectal surgery. The conventional method for evaluating anastomotic perfusion is to observe color change and active bleeding of the resection margin of the intestine and the pulsation of mesenteric vessels. However, the accuracy of this method is low, which may be due to insufficient observation time. A novel surgical procedure that separates the mesentery in advance at the intended transection site can delay the observation of anastomotic perfusion, and can potentially detect more anastomotic sites with insufficient vascular supply and reduce the rate of AL. This study aimed to investigate the effects of a novel surgical procedure on AL following sigmoid colon and rectal cancer surgeries. A total of 343 patients who underwent rectal and sigmoid colon cancer surgeries were included in the study. From August 2021 to June 2022, patients with sigmoid colon or rectal cancer underwent a new surgical procedure of pre-division of the mesentery (PDM) at the intended transection site (PDM group). Patients with colorectal cancer who underwent conventional surgical procedures from August 2018 to July 2021 were categorized as the non-PDM group. Symptomatic AL (SAL) within 30 days and other outcomes were retrospectively analyzed using propensity score matching and compared between the two groups. The incidences of SAL were 1.3% and 11.3% in the PDM and non-PDM groups, respectively. PDM significantly reduced the SAL rate in sigmoid colon and rectal cancer surgeries (P = 0.009). The incidence of total postoperative complications (P < 0.05) was significantly lower in the PDM group than that in the non-PDM group. There were no significant differences between the two groups for operative time (P = 0.662), intraoperative blood loss (P = 0.651), intraoperative blood transfusion (P = 0.316), and intensive care rate (P = 1). The length of postoperative hospital stay (P = 0.010) and first exhaust (P = 0.001) and defecation time (P < 0.05) were shorter in the PDM group than in the non-PDM group. PDM can effectively prevent AL, and this procedure can be safely performed in sigmoid colon and rectal cancer surgeries.

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).

Assessment of Anastomotic Viability With Spectroscopic Real-time Oxygen Saturation Measurement in a Porcine Study

OBJECTIVE

Anastomotic leakage (AL) is a severe complication following intestinal procedures. Intra.Ox™ by ViOptix Inc (Newark, CA, USA) is a novel, FDA-approved spectroscopic device which enables real-time measurement of mixed tissue oxygen saturation (StO₂). Using a porcine model, this study explores the correlation between StO₂ measurements and AL formation as well as investigates the applicability of Intra.Ox™ in the clinical setting.

METHODS

Eleven female swine were divided into 3 groups to explore AL formation in different ischemic conditions. Group 1: 100% mesenteric-vascular ligation, n = 3; Group 2: 50% ligation, n = 5; Group 3: No mesenteric ligation, n = 3. StO₂ at the anastomotic line was measured before and after vessel ligation and anastomosis. Measurements were taken at 6 distinct locations along afferent and efferent loops. AL was evaluated on postoperative day 5 by re-laparotomy.

RESULTS

AL rate was 100%, 60% and 0% in groups 1, 2 and 3, respectively. Post-anastomotic StO₂ in group 1 (22.9 ± 18.5%) and 2 (39.2 ± 20.1%) were significantly lower than in group 3 (53.1 ± 8.3%, p<.0001). Post-anastomotic StO₂ readings ≤40% indicated AL potential with 100% sensitivity,+ 80% specificity, positive predictive value of 85.7% and negative predictive value of 100%.

CONCLUSION

This study demonstrates the value of Intra.Ox™ in assessing local perfusion and indicate the association between low StO₂ and AL by providing accurate, real-time, noninvasive tissue oxygenation measurements at anastomotic sites. Further studies are required to investigate the clinical application of this novel device in intestinal surgery.

Bowel perfusion demonstrated using indocyanine green fluorescence imaging in two cases of strangulated ileus

We report the use of indocyanine green (ICG) fluorescence for intraoperative diagnosis in two cases of strangulated ileus. We successfully preserved the bowel and avoided postoperative complications by detecting adequate perfusion and no necrosis in the intestine's strangulated regions. In the first case, enhanced computed tomography (CT) revealed a closed loop intestine, which showed poor contrast, and we performed laparotomy with ICG fluorescence. In the second case, the CT scan revealed bowel obstruction without ascites. We conservatively treated the patient with the insertion of a long tube. The patient's condition did not improve, and we performed laparotomy using ICG fluorescence. In both of these cases, the visual observation during laparotomy showed that the ileum had dark-red discoloration. We demonstrated perfusion and preserved the ileum by injecting 2.5 mg of ICG intravenously; fluorescence was observed in the dark-red ileum using the PINPOINT system (Novadaq, Kalamazoo, MI, US). Both patients recovered successfully after the surgery with no adverse events. Our data suggest that ICG fluorescence imaging can be one of the decision-making modalities in patients with strangulated ileus.