Indocyanine green-enhanced fluorescence to assess bowel perfusion during laparoscopic colorectal resection. Surg Endosc. 2016;30:2736-2742. [PMID: 26487209 PMCID: PMC4912584 DOI: 10.1007/s00464-015-4540-z]

Usefulness of intraoperative colonoscopy and synchronous scoring system for determining the integrity of the anastomosis in left-sided colectomy: a single-center retrospective cohort study

OBJECTIVES

The aim of this study is to evaluate the utilization of intraoperative colonoscopy (IOC) for determining the integrity of the anastomosis and to establish an IOC scoring system.

METHODS

A retrospective cohort study was conducted from January 2021 to June 2024, we analyzed the clinical data of 160 patients registered in a database who underwent laparoscopic left-sided colectomy at Pusan National University Yangsan Hospital. IOC was performed on all patients, and Mucosal color (MC), stapled line bleeding (BL), proximal redundancy (PR), and bowel preparation (BP) were evaluated and scored as variables. Logistic regression analysis was used to evaluate risk factors for anastomotic leakage (AL) and Cohen's kappa was applied to assess the reproducibility of the evaluation.

RESULTS

Of 160 patients, 10 (6.25%) experienced AL. All the IOC variables had kappa values of 0.8 or higher, indicating good agreement. The logistic regression analysis revealed significant differences in the MC 2 (P = 0.017, OR 12.86), PR 2 (P = 0.001, OR 27.64), BP 2 (p = 0.016, OR 10.50) PR 2 score (P = 0.016, OR 10.50) and the sum of the scores (p = 0.001, OR 3.51).

CONCLUSION

IOC can be performed as a reference procedure to assess the integrity of the anastomosis during left-sided colorectal surgery.

Preoperative Diagnosis and Indocyanine Green (ICG) Fluorescence-Guided Surgery for Uterine Broad Ligament Hernia: A Case Report

Uterine broad ligament hernia is a rare cause of bowel obstruction in women, often challenging to diagnose preoperatively. We report a case of a 73-year-old woman presenting with abdominal pain and vomiting. CT imaging revealed an incarcerated small bowel loop within the Douglas pouch, with displacement of the uterus, leading to a diagnosis of strangulated bowel obstruction due to a broad ligament hernia. An emergency laparotomy identified an ileal segment trapped in a defect of the left broad ligament. The bowel appeared ischemic, but intraoperative indocyanine green (ICG) fluorescence imaging confirmed adequate perfusion, allowing for preservation without resection. The hernial defect was repaired, and the patient recovered without complications. This case highlights the importance of early CT diagnosis and the utility of ICG fluorescence imaging in assessing bowel viability, aiding surgical decision-making, and preventing unnecessary resection in cases of prolonged strangulation.

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.

Monomeric or Homodimer Conjugates of Fibroblast Activation Protein Inhibitor and Cyanine 7 Bearing a Meso-Chloride as Near-Infrared Fluorescence Probes: Design, Synthesis, and Comparative In Vivo Imaging of Distinct Breast Cancer Subtypes

Intraoperative fluorescence navigation can illuminate the tumor, directing surgeons to accurately achieve negative margins, which not only reduces recurrence but also minimizes the incidence of complications. Herein, we developed two near-infrared fluorescent probes FAPI-Cy7-Cl (Emmax = 820 nm) and (FAPI)2-Cy7-Cl (Emmax = 823 nm) with prolonged tumor retention (>72 h) and high target-to-background ratios (up to 4.5) based on the conjugation of pan-cancer targeted fibroblast activation protein inhibitor (FAPI) and the "tumor-seeking" Cyanine 7 bearing a meso-chloride and a cyclohexenyl skeleton (Cy7-Cl). Specifically, FAPI-Cy7-Cl exhibited superior imaging performance in both estrogen receptor α positive breast cancer (MCF-7) and triple-negative breast cancer (TNBC) (MDA-MB-231) subtypes in mouse models. Notably, in the MDA-MB-231 tumor-bearing model, the tumor-to-liver ratio (T/L) of FAPI-Cy7-Cl increased rapidly after 2 h postinjection, reaching nearly 4.5 at 48 h, making it an optimal imaging probe for guiding TNBC surgery resection.

Impact of indocyanine green on decision making for performing laparoscopic cortical sparing adrenalectomy

BACKGROUND

Indocyanine green imaging (ICG) is an expansion technology that can contribute to the development of demanding techniques such as cortical-sparing adrenalectomy (CSA). The aim of this study was to determine in which cases CSA should be performed and when total adrenalectomy should be performed instead based on ICG fluorescence. Here, we present our experience through a series of cases and videos.

METHODS

Prospective and descriptive study on patients with surgical adrenal lesions who were proposed for CSA using ICG with near-infrared fluorescence imaging in our center. A first bolus of 6,25 mg ICG was administered intravenously upon exposure of the retroperitoneal plane. Fluorescence was visualized using a Storz® NIR/ICG endoscopic system.

RESULTS

Seven patients were proposed for CSA. After the application of ICG, a change in attitude was carried out in 71.4% of the cases (five of seven). In the two patients in whom CSA could be performed, the adrenal remnants were functional, and the resection margins of the surgical specimens were free of disease. The reasons why partial adrenalectomy could not be completed, and a total adrenalectomy was decided instead were the presence of a tumor located very close to the adrenal vein that prevented a correct remnant volume (n = 4) and one case of isofluorescent tumor with the adrenal parenchyma.

CONCLUSION

ICG fluorescence guidance could help in the decision making to select patients intraoperatively for successful cortical preservation.

Anastomotic diversion rates following integration of indocyanine green fluorescence angiography in cytoreductive surgery for ovarian cancer

OBJECTIVE

To compare rates of diverting ileostomy in patients with ovarian cancer, undergoing cytoreduction with bowel resection before and after the acquisition of indocyanine green fluorescence angiographic scans for anastomotic perfusion assessment.

METHODS

A retrospective cohort study of patients with ovarian cancer undergoing bowel resection during cytoreductive surgery between 2010 and 2021. We evaluated whether using indocyanine green fluorescence angiography impacted rates of diverting ileostomy. Baseline characteristics and rates of diversion were compared between those who had indocyanine green fluorescence assessment and those with bowel resection without anastomotic fluorescence assessment.

RESULTS

Overall, 181 patients were included. Of whom, 84 (46%) underwent anastomotic fluorescence assessment following bowel resection, and 97 (54%) had bowel resection without assessment. Mean age of the cohort was 58.2 years and 132 (73%) had stage III disease. There was no difference between groups in rates of diverting ileostomy (41% vs 41%, p=1.0). In a univariable logistic regression, the odds of having an ileostomy were 2.92 times higher in patients undergoing primary surgery than in patients undergoing interval cytoreductive surgery (95% CI 1.25 to 6.85, p=0.013). The use of fluorescence angiography did not predict performing diverting ileostomy (OR=0.97, 95% CI (0.53 to 1.76), p=0.92).

CONCLUSION

In this cohort, the simple introduction of indocyanine green fluorescence angiography had no impact on the rates of anastomotic diversion. Developing a systematic, reproducible diversion protocol with selection criteria that include fluorescence angiography is needed to assess the impact of this surgically innovative tool on the rates of anastomotic diversion in patients with advanced ovarian cancer.

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.

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Infrared Fluorescence-guided Surgery for Tumor and Metastatic Lymph Node Detection in Head and Neck Cancer

In patients with head and neck cancer (HNC), surgical removal of cancerous tissue presents the best overall survival rate. However, failure to obtain negative margins during resection has remained a steady concern over the past 3 decades. The need for improved tumor removal and margin assessment presents an ongoing concern for the field. While near-infrared agents have long been used in imaging, investigation of these agents for use in HNC imaging has dramatically expanded in the past decade. Targeted tracers for use in primary and metastatic lymph node detection are of particular interest, with panitumumab-IRDye800 as a major candidate in current studies. This review aims to provide an overview of intraoperative near-infrared fluorescence-guided surgery techniques used in the clinical detection of malignant tissue and sentinel lymph nodes in HNC, highlighting current applications, limitations, and future directions for use of this technology within the field. Keywords: Molecular Imaging-Cancer, Fluorescence © RSNA, 2024.

Surgical margin status outcome of intraoperative indocyanine green fluorescence-guided laparoscopic hepatectomy in liver malignancy: a systematic review and meta-analysis

BACKGROUND

Hepatectomy stands as a curative management for liver cancer. The critical factor for minimizing recurrence rate and enhancing overall survival of liver malignancy is to attain a negative margin hepatic resection. Recently, Indocyanine green (ICG) fluorescence imaging has been proven implemental in aiding laparoscopic liver resection, enabling real-time tumor identification and precise liver segmentation. The purpose of this study is to conduct a systematic review and meta-analysis to ascertain whether ICG-guided laparoscopic hepatectomy yields a higher incidence of complete tumor eradication (R0) resections.

METHODS

The search encompassed databases such as PubMed, Cochrane Library database, Scopus, ScienceDirect, and Ovid in April 2024, in strict adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies involving patients with malignant liver lesions who underwent ICG-guided laparoscopic hepatectomy and reported R0 resection outcomes were eligible for inclusion in this review.

RESULTS

In a total of seven studies, involving 598 patients, were included in the meta-analysis. The ICG demonstrated a significantly elevated R0 resection rate compared to the non-ICG group [98.6% (359/364) vs. 93.1% (339/364), odds ratio (OR) = 3.76, 95% confidence intervals (CI) 1.45-9.51, P = 0.005]. Notably, no heterogeneity was observed (I2 = 0%, P = 0.5). However, the subtype analysis focusing on hepatocellular carcinoma [98.2% (165/168) vs. 93.6% (161/172), OR = 3.34, 95% CI 0.94-11.91, P = 0.06) and the evaluation of margin distance (4.96 ± 2.41 vs. 2.79 ± 1.92 millimeters, weighted mean difference = 1.26, 95% CI -1.8-4.32, P = 0.42) revealed no apparent differences. Additionally, the incidence of overall postoperative complications was comparable between both groups, 27.6% (66/239) in the ICG group and 25.4% (75/295) in the non-ICG group (OR = 0.96, 95% CI 0.53-1.76, P = 0.9). No disparities were identified in operative time, intraoperative blood loss, postoperative blood transfusion, and length of hospital stay after the surgery.

CONCLUSIONS

The implementation of ICG-guided laparoscopic hepatectomy can be undertaken with confidence, as it does not compromise either intraoperative or postoperative events. Furthermore, the ICG-guided approach is beneficial to achieving a complete eradication of the tumor during hepatic resection.

TRIAL REGISTRATION

PROSPERO registration number CRD42023446440.

Utilization of Indocyanine Green (ICG) Fluorescence in Patients with Pediatric Colorectal Diseases: The Current Applications and Reported Outcomes

In pediatric colorectal surgery, achieving and visualizing adequate perfusion during complex reconstructive procedures are paramount to ensure postoperative success. However, intraoperative identification of proper perfusion remains a challeng. This review synthesizes findings from the literature spanning from January 2010 to March 2024, sourced from Medline/PubMed, EMBASE, and other databases, to evaluate the role of indocyanine green (ICG) fluorescence imaging in enhancing surgical outcomes. Specifically, it explores the use of ICG in surgeries related to Hirschsprung disease, anorectal malformations, cloacal reconstructions, vaginal agenesis, bladder augmentation, and the construction of antegrade continence channels. Preliminary evidence suggests that ICG fluorescence significantly aids in intraoperative decision-making by improving the visualization of vascular networks and assessing tissue perfusion. Despite the limited number of studies, initial findings indicate that ICG may offer advantages over traditional clinical assessments for intestinal perfusion. Its application has demonstrated a promising safety profile in pediatric patients, underscoring the need for larger, prospective studies to validate these observations, quantify benefits, and further assess its impact on clinical outcomes. The potential of ICG to enhance pediatric colorectal surgery by providing real-time, accurate perfusion data could significantly improve surgical precision and patient recovery.

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.

Fluorescence-guided minimally-invasive resection of abdominal paragangliomas using indocyanine green

This retrospective study explores the utility of near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) in enhancing the intraoperative identification and guidance for the resection of abdominal paragangliomas. They can be challenging to detect during minimally invasive surgery, due to their anatomical location, varying size and similar appearance in regard to their surrounding tissue. Patients with suspected abdominal paragangliomas planned for a minimally-invasive resection were included. As part of standard of care they received single intravenous dose of 5 mg ICG after abdominal exploration. NIR fluorescence imaging of the anatomical region of the suspected lesion was performed immediately following intravenous administration, to assess fluorescence signals, intraoperative identification, and histopathological correlation. Out of five resected suspicious lesions, four were imaged with NIR fluorescence, pathology confirming four as paragangliomas, the latter turned out to be an adrenal adenoma. NIR fluorescence identified all four lesions, surpassing the limitations of white-light visualization. Homogeneous fluorescence signals appeared 30-60 s post-ICG administration, which lasted up to 30 min. The study demonstrates the feasibility and potential clinical value of fluorescence-guided minimally-invasive resections of abdominal paragangliomas using a single intravenous ICG dose. These findings support the scientific basis for routine use of ICG-fluorescence-guided surgery in challenging anatomical cases, providing valuable assistance in lesion detection and resection.

Utility of indocyanine green fluorescent dye in emergency general surgery: a review of the contemporary literature

For decades, indocyanine green (ICG) has been available for medical and surgical use. The indications for ICG use in surgery have expanded where guided surgery directed by fluorescence and near-infrared fluorescent imaging offers numerous advantages. Recently, surgeons have reported using ICG operative navigation in the emergency setting, with fluorescent cholangiography being the most common procedure. The utility of ICG also involves real-time perfusion assessment, such as ischemic organs and limbs. The rising use of ICG in surgery can be explained by the ICG's rapid technological evolution, accuracy, ease of use, and great potential to guide precision surgical diagnosis and management. The review aims to summarize the current literature on the uses of ICG in emergency general surgery. It provides a comprehensive and practical summary of the use of ICG, including indication, route of administration, and dosages. To simplify the application of ICG, we subdivided its use into anatomical mapping and perfusion assessment. Anatomical mapping includes the biliary tree, ureters, and bowel. Perfusion assessment includes bowel, pancreas, skin and soft tissue, and gonads. This review provides a reference to emergency general surgeons to aid in implementing ICG in the emergency setting for more enhanced and safer patient care.

Efficacy and safety of near-infrared fluorescence identification of the thoracic duct during left lateral neck dissection

BACKGROUND

Thoracic duct leaks occur in up to 5% of left lateral neck dissections. No one imaging modality is routinely used to identify the thoracic duct intraoperatively. The goal of our study was to evaluate the efficacy and safety of indocyanine green lymphangiography for intraoperative identification of the thoracic duct compared to traditional methods using ambient and evaluate the optimal timing of indocyanine green administration.

METHODS

We enrolled all patients who underwent left lateral neck dissection at our institution from 2018 to 2022 in this prospective clinical trial. After indocyanine green injection into the dorsum of the foot, we performed intraoperative imaging was performed with a near-infrared fluorescence camera. We reported the data using descriptive statistics.

RESULTS

Of the 42 patients we enrolled, 14 had prior neck surgery, and 3 had prior external beam radiation. We visualized the thoracic duct with ambient light in 48% of patients and with near-infrared fluorescence visualization in 64%. In 17% of patients, we could identify the thoracic duct only using near-infrared fluorescence visualization, which occurred within 3 minutes of injection, and were required to re-dose 5 patients. We visualized the thoracic duct with near-infrared fluorescence in all patients with prior neck radiation and 77% of patients with prior neck surgery. One adverse reaction occurred (hypotension), and 5 intraoperative thoracic duct injuries occurred that were ligated. There with no chylous fistulas postoperatively.

CONCLUSION

This trial demonstrates that near-infrared fluorescence identification of the thoracic duct is feasible and safe with indocyanine green lymphangiography, even in patients with prior neck surgery or radiation.

Best Evidence for Each Surgical Step in Minimally Invasive Right Hemicolectomy: A Systematic Review

Objective

The aim of this study was to systematically review the literature for each surgical step of the minimally invasive right hemicolectomy (MIRH) for non-locally advanced colon cancer, to define the most optimal procedure with the highest level of evidence.

Background

High variability exists in the way MIRH is performed between surgeons and hospitals, which could affect patients' postoperative and oncological outcomes.

Methods

A systematic search using PubMed was performed to first identify systematic reviews and meta-analyses, and if there were none then landmark papers and consensus statements were systematically searched for each key step of MIRH. Systematic reviews were assessed using the AMSTAR-2 tool, and selection was based on highest quality followed by year of publication.

Results

Low (less than 12 mmHg) intra-abdominal pressure (IAP) gives higher mean quality of recovery compared to standard IAP. Complete mesocolic excision (CME) is associated with lowest recurrence and highest 5-year overall survival rates, without worsening short-term outcomes. Routine D3 versus D2 lymphadenectomy showed higher LN yield, but more vascular injuries, and no difference in overall and disease-free survival. Intracorporeal anastomosis is associated with better intra- and postoperative outcomes. The Pfannenstiel incision gives the lowest chance of incisional hernias compared to all other extraction sites.

Conclusion

According to the best available evidence, the most optimal MIRH for colon cancer without clinically involved D3 nodes entails at least low IAP, CME with D2 lymphadenectomy, an intracorporeal anastomosis and specimen extraction through a Pfannenstiel incision.

Evaluation of testicular blood flow during testicular torsion surgery in children using the indocyanine green-guided near-infrared fluorescence imaging technique

Objective

This study investigates the feasibility of the indocyanine green-guided near-infrared fluorescence (ICG-NIRF) imaging technique in evaluating testicular blood flow during testicular torsion (TT) surgery in pediatric cases.

Methods

We retrospectively analyzed the eight pediatric patients with TT who underwent surgery in our hospital between February and July 2023. The intraoperative two-step method of ICG-NIRF imaging and testicular incision was used to evaluate the testicular blood flow, followed by a selection of different surgical methods. The removed testes were pathologically examined after surgery, and all patients were followed up 1 month after surgery to evaluate testicular blood flow using gray-scale ultrasound and color Doppler flow imaging (CDFI).

Results

Eight pediatric TT patients aged 1-16 years, with a median age of 11.5 years, were enrolled. Time from the onset ranged from 4 to 72 h (mean 26.13 ± 25.09 h). A total of eight testes were twisted, including four on the left side and four on the right side. The twisting direction of the testes was clockwise in four cases and counterclockwise in four cases. The rotation of torsion was 180°-1,080° (mean 472.5° ± 396°). There was no statistically significant difference in the imaging time between the four patients with testicular blood vessel imaging on both the torsional and normal sides (P > 0.05). The postoperative recovery was uneventful, with no complications during the follow-up period of 1 month. The postoperative histopathological results of three patients who underwent orchiectomy showed extensive hemorrhage, degeneration, and necrosis of the testicular tissue. Among the five patients who underwent orchiopexy, a gray-scale ultrasound and CDFI examinations showed uniform internal echo of the testes and normal blood flow signals in four patients. One patient with no testicular blood vessel imaging on the torsional side showed uneven internal echo of the testis and no blood flow signals.

Conclusion

ICG-NIRF imaging is a feasible method to evaluate testicular blood flow during TT surgery. Testicular blood vessel imaging within 5 minutes after ICG injection might be the basis for testicular retention during TT surgery.

Risk assessment of rectal anastomotic leakage (RAREAL) after DIXON in non-emergency patients with rectal cancer

BACKGROUND

The routine establishment of a diverting stoma (DS) remains controversial in every patient undergoing Dixon operation. We aimed to establish a model for the risk assessment of rectal anastomotic leak (RAREAL) after Dixon in non-emergency patients with rectal cancer, using routinely available variables, by which surgeons could individualize their approach to DS.

METHODS

323 patients who underwent Dixon operation for rectal cancer from January 2015 to December 2018 were taken as the model group for retrospective study. Univariable and multivariable logistic regression analysis was used to determine the independent risk factors associated with anastomotic leakage. We constructed the RAREAL model. 150 patients who underwent Dixon operation due to rectal cancer from January 2019 to December 2020 were collected according to the uniform criteria as a validation group to validate the RAREAL model.

RESULTS

In the model group, multivariable analysis identified the following variables as independent risk factors for AL: HbA1c (odds ratio (OR) = 4.107; P = 0.044), Left colic artery (LCA) non preservation (OR = 4.360; P = 0.026), Tumor distance from the anal margin (TD) (OR = 6.373; P = 0.002). In the model group, the area under the curve (AUC) of the receiver operating characteristic (ROC) for evaluating AL with RAREAL was 0.733, and when RAREAL score = 2.5, its sensitivity, specificity and Youden index were 0.385, 0.973, 0.358, respectively. The AUC was 0.722 in the validation group and its sensitivity and specificity were 0.333 and 0.985, respectively, when RAREAL score = 2.5.

CONCLUSION

The RAREAL score can be used to assess the risk of AL after Dixon operation for rectal cancer, and prophylactic DS should be proactively done when the score is greater than 2.5.

Lymphatic flow mapping during colon cancer surgery using indocyanine green fluorescence imaging

With the development of surgical technology, indocyanine green (ICG) fluorescence navigation systems may be useful in various areas of colorectal surgery, including tumor location confirmation, bowel perfusion, ureter identification, and lymph node mapping. This review provides an overview of the current status of ICG-based navigation surgery in colorectal surgery, emphasizing its role in lymphatic flow mapping. This state-of-the-art approach will allow for appropriate oncological surgeries in the field of colorectal cancer and improve the patient's prognosis.

Fluorescent ICG angiography in laparoscopic rectal resection - a randomized controlled trial. Preliminary report

Introduction

Anastomotic leakage is one of the most dangerous complications after rectal surgery. It can cause systemic complications, reduce the quality of life and worsen the results of oncological treatment. One of the causes of anastomotic leak is insufficient blood supply to the anastomosis. Intraoperative infrared angiography with indocyanine green (ICG) is expected to improve the assessment of intestinal perfusion and thus prevent anastomotic leakage.

Aim

To present the results of the use of ICG intraoperative angiography during rectal surgery in the prevention of anastomotic leakage.

Material and methods

The study included 76 patients undergoing rectal cancer surgery. Patients were randomized to 2 groups: Group I - 41 patients with ICG intraoperative angiography; and Group II - 35 patients without ICG imaging. Anastomotic leak, length of hospitalization, and complication rate were compared.

Results

Group I patients received intravenous ICG before the anastomosis. Average time of intestinal wall contrasting was 42 s (22-65 s). Average ICG procedure time was 4 min (3.2% of total time of surgery). Three (7.3%) patients after angiography revealed intestinal ischemia requiring widened resection. No anastomotic leak was found post-operatively, and no side effects were observed after administration of ICG. In group II, 3 (8.6%) anastomotic leakages were diagnosed, 2 of which required reoperation.

Conclusions

Intraoperative angiography with ICG in near-infrared light is a safe and effective method of assessing intestinal perfusion. ICG angiography may change the surgical plan and reduce the risk of anastomotic leakage. It is necessary to continue the study until the assumed number of patients is reached.

Research progress of minimally invasive surgery for gastric cancer

Since the first laparoscopic radical surgery for early gastric cancer 30 years ago, there has been a gradual shift from "open" to "minimally invasive" surgery for gastric cancer. This transition is due to advancements in refined anatomy, enlarged field of view, faster recovery, and comparable oncological outcomes. Several high-quality clinical studies have demonstrated the safety and effectiveness of laparoscopy in the treatment of both early and locally advanced gastric cancer. The role of perioperative chemotherapy in managing locally advanced gastric cancer has been widely recognized, and there have been continuous breakthroughs in the exploration of targeted therapy and immunotherapy for perioperative treatment. Additionally, the application of indocyanine green near-infrared imaging technology, 3D laparoscopic technology, and robotic surgery systems has further improved the accuracy and minimally invasive nature of gastric cancer surgeries. Looking ahead, the field of minimally invasive surgery for gastric cancer is expected to become more standardized, resulting in a significant enhancement in the quality of life for gastric cancer patients.

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.

A Hypothetical New Challenging Use for Indocyanine Green Fluorescence during Laparoscopic Appendectomy: A Mini-Series of Our Experience and Literary Review

Laparoscopic appendectomy (LA) is a well-standardized surgical procedure, but there are still controversies about the different devices to be used for the appendiceal stump closure and the related postoperative complications. Indocyanine green (ICG) fluorescence angiography (FA) has already been shown to be helpful in elective and emergency surgery, providing intraoperative information on tissue and organ perfusion, thus guiding the surgical decisions and the technical strategies. According to these two aspects, we report a mini-series of the first five patients affected by gangrenous and flegmonous acute appendicitis intraoperatively evaluated with ICG-FA during LA. The patients were admitted to the Emergency Department with an usual range of symptoms for acute appendicitis. The patients were successfully managed by fully LA with the help of a new hypothetical challenging use of ICG-FA.

Laser speckle contrast imaging compared with indocyanine green in renal perfusion of a porcine model

Background

When viewed under near-infrared light, indocyanine green (ICG) signal for kidney perfusion can be utilized in partial nephrectomy. Laser speckle contrast imaging (LSCI) uses coherent light to detect perfusion during real-time laparoscopic surgery.

Materials and methods

Laser speckle contrast imaging or ActivSight, an imaging sensor adapter, was used during laparoscopy of an anesthetized porcine kidney model. ActivSight's "perfusion mode" and "quantification mode" displayed the blood flow as a heatmap and numerical signal intensity, respectively.

Results

After the upper segmental renal artery was clamped, ICG was seen in the lower pole, and LSCI showed low unit (dark color) quantification and perfusion in the upper pole. Indocyanine green was retained in the lower pole after the upper segmental artery was unclamped, and LSCI perfusion was demonstrated in the entire kidney.

Conclusions

Laser speckle contrast imaging is a dye-free, repeatable, real-time adjunct for renal parenchymal perfusion assessment applicable to minimally invasive renal surgery to complement the technology of ICG near-infrared fluorescence and advance digital surgery.

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.

Use of intraoperative indocyanine green fluorescence in determining testicular viability in testicular torsion patients in rural settings: A case report

INTRODUCTION AND IMPORTANCE

Testicular torsion (TT) is the result of spermatic cord twisting which can lead to significant ischemia, making it a time-sensitive surgical emergency. General surgeons in rural centers may lack the resources to adequately evaluate the viability of the affected testicle. Indocyanine green fluorescence (IGF) has been increasingly used to assess vascular perfusion in general surgery cases. In this case report, we show the use of IGF in a rural setting to assess testicular viability in TT.

CASE PRESENTATION

A 17-year-old male was transferred to our rural regional hospital emergency department for sudden and persistent right scrotal pain. The onset of symptoms was approximately 52 h at presentation. TT was diagnosed with a doppler ultrasound by a radiologist. Urgent detorsion surgery was performed. Intraoperative assessment of viability was unclear after the usual means and IGF helped confirm the absence of testicle vascularization and the need for orchiectomy.

CLINICAL DISCUSSION

General surgeons in rural communities are called to manage TT with limited resources and experience. IGF is widely used in general surgery and urology. Animal studies and two case reports show potential benefits of IGF in TT. In our patient, IGF was useful to confirm without a doubt that the right testicle was ischemic and non-viable.

CONCLUSION

In a rural setting with limited access to radiology and distant urology coverage, IGF is an excellent resource to determine intraoperative blood flow in TT with uncertain viability.

Is ICG essential in all colorectal surgery? A 3-year experience in a single center: a cohort study

INTRODUCTION AND OBJECTIVES

Indocyanine green (ICG) was introduced as a promising diagnostic tool to provide real-time assessment of intestinal vascularization. Nevertheless, it remains unclear whether ICG could reduce the rate of postoperative AL. The objective of this study is to assess its usefulness and to determine in which patients is most useful and would benefit the most from the use of ICG for intraoperative assessment of colon perfusion.

METHODS

A retrospective cohort study was conducted in a single center, including all patients who underwent colorectal surgery with intestinal anastomosis between January 2017 and December 2020. The results of patients in whom ICG was used prior to bowel transection were compared with the results of the patients in whom this technique was not used. Propensity score matching (PSM) was employed to compare groups with and without ICG.

RESULTS

A total of 785 patients who underwent colorectal surgery were included. The operations performed were right colectomies (35.0%), left colectomies (48.3%), and rectal resections (16.7%). ICG was used in 280 patients. The mean time since the infusion of ICG until detection of fluorescence in the colon wall was 26.9 ± 1.2 s. The section line was modified in 4 cases (1.4%) after ICG due to a lack of perfusion in the chosen section line. Globally, a non-statistically significant increase in anastomotic leak rate was observed in the group without ICG (9.3% vs. 7.5%; p = 0.38). The result of the PSM was a coefficient of 0.026 (CI - 0.014 to 0.065, p = 0.207).

CONCLUSIONS

ICG is a safe and useful tool to assess the perfusion of the colon prior to performing the anastomosis in colorectal surgery. However, in our experience, it did not significantly lower the anastomotic leakage rate.

The role of intraoperative hyperspectral imaging (HSI) in colon interposition after esophagectomy

BACKGROUND

Colon conduit is an alternative approach to reconstructing the alimentary tract after esophagectomy. Hyperspectral imaging (HSI) has been demonstrated to be effective for evaluating the perfusion of gastric conduits, but not colon conduits. This is the first study to describe this new tool addressing image-guided surgery and supporting esophageal surgeons to select the optimal colon segment for the conduit and anastomotic site intraoperatively.

PATIENTS AND METHODS

Of 10 patients, eight who underwent reconstruction with a long-segment colon conduit after esophagectomy between 01/05/2018 and 01/04/2022 were included in this study. HSI was recorded at the root and tip of the colon conduit after clamping the middle colic vessels, allowing us to evaluate the perfusion and appropriate part of the colon segment.

RESULTS

Anastomotic leak (AL) was detected in only one (12.5%) of all the enrolled patients (n = 8). None of the patients developed conduit necrosis. Only one patient required re-anastomosis on postoperative day 4. No patient needed conduit removal, esophageal diversion, or stent placement. There was a change in the anastomosis site to proximal in two patients intraoperatively. There was no need to change the side of colon conduit intraoperatively in any patient.

CONCLUSION

HSI is a promising and novel intraoperative imaging tool to objectively assess the perfusion of the colon conduit. It helps the surgeon to define the best perfused anastomosis site and the side of colon conduit in this type of operation.

Impacts of trans-anal tube placement in patients with sigmoid colon cancer: Risk verification analysis using inverse probability weighting analysis

Purpose

Anastomotic leakage (AL) is a serious postoperative complication that affects short- and long-term outcomes. The use of a trans-anal drainage tube (TDT) is reported to prevent AL in rectal cancer patients, but its value in sigmoid colon cancer patients is unknown.

Methods

Admitted to the study were 379 patients who underwent surgery for sigmoid colon cancer between 2016 and 2020. Patients were divided into two groups according to the placement (n = 197) or nonplacement of a TDT (n = 182). To determine the factors affecting the association between TDT placement and AL, we estimated average treatment effects by stratifying each factor using the inverse probability of treatment weighting method. The association between prognosis and AL was evaluated in each identified factor.

Results

Factors associated with postsurgical insertion of a TDT were advanced age, male sex, high body mass index (BMI), poor performance status, and presence of comorbidities. TDT placement was associated with a significantly lower AL in male patients (odds ratio [OR], 0.22; 95% confidence interval [CI], 0.07-0.73; P = .013) and for BMI ≥ 25 kg/m2 (OR, 0.13; 95% CI, 0.02-0.65; P = .013). In addition, there was a significant association of AL with poor prognosis in patients with BMI ≥ 25 kg/m2 (P = .043), age > 75 y (P = .021), and pathological node-positive disease (P = .015).

Conclusion

Sigmoid colon cancer patients with BMI ≥ 25 kg/m2 are the most appropriate candidates for postoperative TDT insertion, in terms of reduced incidence of AL and improved prognosis.

Feasibility and comparison of laparoscopic laser speckle contrast imaging to near-infrared display of indocyanine green in intraoperative tissue blood flow/tissue perfusion in preclinical porcine models

OBJECTIVE

To determine if laser speckle contrast imaging (LSCI) mitigates variations and subjectivity in the use and interpretation of indocyanine green (ICG) fluorescence in the current visualization paradigm of real-time intraoperative tissue blood flow/perfusion in clinically relevant scenarios.

METHODS

De novo laparoscopic imaging form-factor detecting real-time blood flow using LSCI and blood volume by near-infrared fluorescence (NIRF) of ICG was compared to ICG NIRF alone, for dye-less real-time visualization of tissue blood flow/perfusion. Experienced surgeons examined LSCI and ICG in segmentally devascularized intestine, partial gastrectomy, and the renal hilum across six porcine models. Precision and accuracy of identifying demarcating lines of ischemia/perfusion in tissues were determined in blinded subjects with varying levels of surgical experience.

RESULTS

Unlike ICG, LSCI perfusion detection was real time (latency < 150 ms: p < 0.01), repeatable and on-demand without fluorophore injection. Operating surgeons (n = 6) precisely and accurately identified concordant demarcating lines in white light, LSCI, and ICG modes immediately. Blinded subjects (n = 21) demonstrated similar spatial-temporal precision and accuracy with all three modes ≤ 2 min after ICG injection, and discordance in ICG mode at ≥ 5 min in devascularized small intestine (p < 0.0001) and in partial gastrectomy (p < 0.0001).

CONCLUSIONS

Combining LSCI for near real-time blood flow detection with ICG fluorescence for blood volume detection significantly improves precision and accuracy of perfusion detection in tissue locations over time, in real time, and repeatably on-demand than ICG alone.

In vivo evaluation of a hyperspectral imaging system for minimally invasive surgery (HSI-MIS)

BACKGROUND

Hyperspectral Imaging (HSI) is a reliable and safe imaging method for taking intraoperative perfusion measurements. This is the first study translating intraoperative HSI to an in vivo laparoscopic setting using a CE-certified HSI-system for minimally invasive surgery (HSI-MIS). We aim to compare it to an established HSI-system for open surgery (HSI-Open).

METHODS

Intraoperative HSI was done using the HSI-MIS and HSI-Open at the Region of Interest (ROI). 19 patients undergoing gastrointestinal resections were analyzed in this study. The HSI-MIS-acquired images were aligned with those from the HSI-Open, and spectra and parameter images were compared pixel-wise. We calculated the Mean Absolute Error (MAE) for Tissue Oxygen Saturation (StO₂), Near-Infrared Perfusion Index (NIR-PI), Tissue Water Index (TWI), and Organ Hemoglobin Index (OHI), as well as the Root Mean Squared Error (RMSE) over the whole spectrum. Our analysis of parameters was optimized using partial least squares (PLS) regression. Two experienced surgeons carried out an additional color-change analysis, comparing the ROI images and deciding whether they provided the same (acceptable) or different visual information (rejected).

RESULTS

HSI and subsequent image registration was possible in 19 patients. MAE results for the original calculation were StO_{2 orig.} 17.2% (± 7.7%)_, NIR-PI_orig. 16.0 (± 9.5), TWI_orig. 18.1 (± 7.9), OHI_orig. 14.4 (± 4.5). For the PLS calculation, they were StO_{2 PLS} 12.6% (± 5.2%), NIR-PI_PLS 10.3 (± 6.0), TWI_PLS 10.6 (± 5.1), and OHI_PLS 11.6 (± 3.0). The RMSE between both systems was 0.14 (± 0.06). In the color-change analysis; both surgeons accepted more images generated using the PLS method.

CONCLUSION

Intraoperative HSI-MIS is a new technology and holds great potential for future applications in surgery. Parameter deviations are attributable to technical differences and can be reduced by applying improved calculation methods. This study is an important step toward the clinical implementation of HSI for minimally invasive surgery.

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.

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.

When should indocyanine green be assessed in colorectal surgery, and at what distance from the tissue? Quantitative measurement using the SERGREEN program

BACKGROUND

Suture dehiscence is one of the most feared postoperative complications. Correct intestinal vascularization is essential for its prevention. Indocyanine green (ICG) is one of the methods used to assess vascularization, but this assessment is usually subjective. Our group designed the SERGREEN program to obtain an objective measurement of the degree of vascularization. We do not know how long after ICG administration the fluorescence of the tissues should be evaluated, or how far away the measurement should be performed. The aim of this study is to establish the optimal moment and distance for analyzing the fluorescence saturation of ICG.

METHODS

Prospective observational study in patients undergoing elective laparoscopic colorectal surgery. The optimal time for ICG analysis was tested in a sample of 20 patients (10 right colon and 10 left colon), and the optimal distance in a sample of ten patients. ICG was administered intravenously, and colon vascularization was quantified using SERGREEN; RGB (Red, Green, Blue) encoding was used. The intensity curve of the ICG was analyzed for ten minutes after its administration. Distances of 1, 3, and 5 cm were tested.

RESULTS

The intensity of fluorescence increased until 1.5 min after ICG administration (reaching figures of 112.49 in the right colon and 93.95 in the left). It then remained fairly stable until 3.5 min (98.49 in the right and 83.35 in the left), at which point it began to decrease gradually. ICG saturation was inversely proportional to the distance between the camera and the tissue. The best distance was 5 cm, where the confidence interval was narrower [CI 86.66-87.53].

CONCLUSION

The optimal time for determining ICG in the colon is between 1.5 and 3.5 min, in both right and left colon. The optimal distance is 5 cm. This information will help to establish parameters of comparison in normal and pathological situations.

Intraoperative assessment of bone viability through improved analysis and visualization of dynamic contrast-enhanced fluorescence imaging: technique report

Bone devitalization is believed to be a critical determinant of complications such as infection or nonunion. However, intraoperative assessment of bone devitalization, particularly in open fractures and infections, remains highly subjective resulting in variation in treatment. Optical imaging tools, particularly dynamic contrast-enhanced fluorescence imaging, can provide real-time, intraoperative assessment of bone and soft tissue perfusion, which informs the tissues' ability to heal and fight infection. We describe a novel technique to apply indocyanine green-based fluorescence imaging, using a device that is frequently used in the operating room to assess skin or flap perfusion in plastic surgery, to assess bone and deep tissue perfusion in three pertinent cases: (1) a chronic infection/nonunion after a Gustilo type 3A tibia fracture (patient 1), (2) an acute Gustilo type 3C tibia open fracture with extensive degloving/soft tissue stripping (patient 2), and (3) an atrophic nonunion of the humerus (patient 3). In all three cases, fluorescence imaging (both time-specific fluorescence and maximum fluorescence) and derived kinetic maps of time-to-peak, ingress slope, and egress slope demonstrated clear spatial variation in perfusion that corresponded to the patient pathogenesis. The impact of this information on patient outcome will need to be evaluated in future clinical trials; however, these cases demonstrate in principle that optical imaging information has the potential to inform surgical practice, reduce the variation in treatment, and improve outcomes observed in these challenging patients.

Quantitative evaluation of anastomotic perfusion during colorectal surgery via indocyanine green fluorescence angiography: a narrative review

Background and Objective

Quantitative studies of indocyanine green (ICG) are needed to optimize its evaluative potential in anastomotic perfusion during colorectal surgery. However, some limitations still existed in current studies about qualitative evaluations such as small-scale studies, the inconsistent concentration of the drug, the method of injection, etc. Therefore, this review summarized the primary quantitative parameters, image, method, and so on, during ICG fluorescence angiography aiming to further provide a theoretical basis for the application of ICG in laparoscopic colorectal surgery.

Methods

The following keywords "indocyanine green or ICG", "anastomotic perfusion", and "colorectal surgery" were applied to search for literature published from 2002 to 2022 in the PubMed, Web of Science, and Medline databases. Then, the information about ICG fluorescence angiography in quantitative evaluation of anastomotic perfusion during colorectal surgery was summarized. Through integrating the experiences derived from the literature and our research center, the crucial quantitative parameters [such as T0, Tmax, Fmax, and S (Fmax/Tmax)], image characteristics, and standard operational process for ICG fluorescence angiography were summarized.

Key Content and Findings

Firstly, quantitative parameters, including T0, Tmax, Fmax, and S (Fmax/Tmax) during the ICG fluorescence angiography could predict anastomotic leakage, and thus should be recorded. Secondly, the image curve generated by the software might differ among patients, which included a filling period, reducing period, and platform period; some patients even presented a second fluorescence intensity peak. Finally, present studies presented great heterogeneity regarding the injection dose of ICG, observation distance from the laparoscope to the anastomotic site, software, and so on, during ICG fluorescence angiography in quantitatively evaluating the intestinal blood perfusion.

Conclusions

This review points out the challenges of ICG fluorescence angiography in quantitative evaluation of anastomotic perfusion and gives some advice. However, some difficulties and issues are non-neglectable during the clinical implications of the quantitative evaluation of ICG, such as standardizing the specific cut-off value about the quantitative parameters, injection dose of ICG, observation distance from the laparoscope to the anastomotic site, software, and so on, during ICG fluorescence angiography in quantitatively evaluating the intestinal blood perfusion to eliminate heterogeneity.

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.

Utility and usability of laser speckle contrast imaging (LSCI) for displaying real-time tissue perfusion/blood flow in robot-assisted surgery (RAS): comparison to indocyanine green (ICG) and use in laparoscopic surgery

Background

Utility and usability of laser speckle contrast imaging (LSCI) in detecting real-time tissue perfusion in robot-assisted surgery (RAS) and laparoscopic surgery are not known. LSCI displays a color heatmap of real-time tissue blood flow by capturing the interference of coherent laser light on red blood cells. LSCI has advantages in perfusion visualization over indocyanine green imaging (ICG) including repeat use on demand, no need for dye, and no latency between injection and display. Herein, we report the first-in-human clinical comparison of a novel device combining proprietary LSCI processing and ICG for real-time perfusion assessment during RAS and laparoscopic surgeries.

Methods

ActivSight™ imaging module is integrated between a standard laparoscopic camera and scope, capable of detecting tissue blood flow via LSCI and ICG in laparoscopic surgery. From November 2020 to July 2021, we studied its use during elective robotic-assisted and laparoscopic cholecystectomies, colorectal, and bariatric surgeries (NCT# 04633512). For RAS, an ancillary laparoscope with ActivSight imaging module was used for LSCI/ICG visualization. We determined safety, usability, and utility of LSCI in RAS vs. laparoscopic surgery using end-user/surgeon human factor testing (Likert scale 1–5) and compared results with two-tailed t tests.

Results

67 patients were included in the study—40 (60%) RAS vs. 27 (40%) laparoscopic surgeries. Patient demographics were similar in both groups. No adverse events to patients and surgeons were observed in both laparoscopic and RAS groups. Use of an ancillary laparoscopic system for LSCI/ICG visualization had minimal impact on usability in RAS as evidenced by surgeon ratings of device usability (set-up 4.2/5 and form-factor 3.8/5). LSCI ability to detect perfusion (97.5% in RAS vs 100% in laparoscopic cases) was comparable in both RAS and laparoscopic cases.

Conclusions

LSCI demonstrates comparable utility and usability in detecting real-time tissue perfusion/blood flow in RAS and laparoscopic surgery.

Graphical abstract

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

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

Assessment of blood perfusion quality in laparoscopic colorectal surgery by means of Machine Learning

An innovative algorithm to automatically assess blood perfusion quality of the intestinal sector in laparoscopic colorectal surgery is proposed. Traditionally, the uniformity of the brightness in indocyanine green-based fluorescence consists only in a qualitative, empirical evaluation, which heavily relies on the surgeon's subjective assessment. As such, this leads to assessments that are strongly experience-dependent. To overcome this limitation, the proposed algorithm assesses the level and uniformity of indocyanine green used during laparoscopic surgery. The algorithm adopts a Feed Forward Neural Network receiving as input a feature vector based on the histogram of the green band of the input image. It is used to (i) acquire information related to perfusion during laparoscopic colorectal surgery, and (ii) support the surgeon in assessing objectively the outcome of the procedure. In particular, the algorithm provides an output that classifies the perfusion as adequate or inadequate. The algorithm was validated on videos captured during surgical procedures carried out at the University Hospital Federico II in Naples, Italy. The obtained results show a classification accuracy equal to [Formula: see text], with a repeatability of [Formula: see text]. Finally, the real-time operation of the proposed algorithm was tested by analyzing the video streaming captured directly from an endoscope available in the OR.

Experimental study of the quantification of indocyanine green fluorescence in ischemic and non-ischemic anastomoses, using the SERGREEN software program

Tissue ischemia is a key risk factor in anastomotic leak (AL). Indocyanine green (ICG) is widely used in colorectal surgery to define the segments with the best vascularization. In an experimental model, we present a new system for quantifying ICG fluorescence intensity, the SERGREEN software. Controlled experimental study with eight pigs. In the initial control stage, ICG fluorescence intensity was analyzed at the level of two anastomoses, in the right and in the left colon. Control images of the two segments were taken after ICG administration. The images were processed with the SERGREEN program. Then, in the experimental ischemia stage, the inferior mesenteric artery was sectioned at the level of the anastomosis of the left colon. Fifteen minutes after the section, sequential images of the two anastomoses were taken every 30 min for the following 2 h. At the control stage, the mean scores were 134.2 (95% CI 116.3–152.2) for the right colon and 147 (95% CI 134.7–159.3) for the left colon (p = 0.174) (Scale RGB—Red, Green, Blue). The right colon remained stable throughout the experiment. In the left colon, intensity fell by 47.9 points with respect to the pre-ischemia value (p < 0.01). After the first post-ischemia determination, the values of the ischemic left colon remained stable throughout the experiment. The relative decrease in ICG fluorescence intensity of the ischemic left colon was 32.6%. The SERGREEN program quantifies ICG fluorescence intensity in normal and ischemic situations and detects differences between them. A reduction in ICG fluorescence intensity of 32.6% or more was correlated with complete tissue ischemia.

Intraoperative Colonoscopy in Laparoscopic Rectal Cancer Surgery Reduces Anastomotic Leakage

Objectives:

Anastomotic leakage (AL) is the most severe complication of colorectal surgery and is a frequent cause of postoperative mortality. This study aimed to identify the risk factors for AL, including the type of air leak test (ALT) performed, in patients undergoing laparoscopic colorectal cancer surgery.

Methods:

This study involved a retrospective review of 201 patients who underwent elective laparoscopic procedures using circular stapled anastomosis for colorectal cancer between January 2015 and December 2020 at Kyorin University Hospital, Tokyo, Japan. In all cases, the distance from the anal verge to the anastomotic site was within 15 cm.

Results:

Overall, AL was observed in 16 patients (8.0%). Univariate analysis revealed that the risk factors for AL included diabetes (P = 0.068), tumor location (P = 0.049), level of anastomosis (P = 0.002), number of linear stapler firings (P = 0.007), and intraoperative colonoscopy (IOCS; P = 0.069). Multivariate analysis revealed that the level of anastomosis (P = 0.029) and IOCS (P = 0.039) were significant and independent risk factors for AL. One of the 107 patients undergoing ALT without IOCS and 3 of the 94 patients undergoing ALT with IOCS were proven to be positive for air leak. However, these four patients underwent additional suturing intraoperatively and developed no AL following surgery.

Conclusions:

This study identified the level of anastomosis and ALT with IOCS as predictors for AL. The results of our study indicate that ALT with IOCS may be more effective than ALT without IOCS in the diagnosis and prevention of AL.

Mesenteric Vascular Evaluation with Pre-operative Multidetector Computed Tomographic Angiography and Intraoperative Indocyanine Green Angiography to Reduce Anastomotic Leaks after Minimally Invasive Surgery for Colorectal Cancer

Background

The aim of this prospective study was to determine the effect of mesenteric vascular evaluation using pre-operative multidetector computed tomography angiography (MDCTA) and intraoperative indocyanine green (ICG) angiography on reducing the anastomotic leak rate of colorectal cancer patients undergoing minimally invasive resection.

Methods

Twenty-seven consecutive patients with colorectal cancer were studied, 18 males and 9 females, average age 69.1 ± 3.9 years. All patients underwent pre-operative mesenteric vascular evaluation using MDCTA with three-dimensional (3D) reconstruction and intraoperative evaluation of perfusion using ICG angiography. Twelve patients underwent laparoscopic resection (Olympus Visera Elite II OTV-S200) and 15 patients underwent robotic resection (DaVinci Si). Colorectal resection lines and anastomoses were guided by intraoperative ICG perfusion. Postoperative anastomotic leaks were assessed.

Results

Pre-operative MDCTA 3D reconstructions defined the left colic and sigmoid artery anatomy and guided operative planning. The intraoperative ICG angiography resulted in a change of the planned lines of resection in seven patients (26%). The rate of postoperative anastomotic leaks in this study was 0% (0/27), compared to a leak rate of 6.8% at our institution in the preceding two years.

Conclusion

Pre-operative evaluation of mesenteric vascular anatomy using MDCTA with 3D reconstruction and intraoperative evaluation of perfusion using ICG angiography were found to be technically feasible and safe. An appropriately designed study should be undertaken to prove whether it was truly effective at reducing the postoperative anastomotic leak rate in colorectal cancer patients undergoing minimally invasive resection at our institution.

Deep Learning to Measure the Intensity of Indocyanine Green in Endometriosis Surgeries with Intestinal Resection

Endometriosis is a gynecological pathology that affects between 6 and 15% of women of childbearing age. One of the manifestations is intestinal deep infiltrating endometriosis. This condition may force patients to resort to surgical treatment, often ending in resection. The level of blood perfusion at the anastomosis is crucial for its outcome, for this reason, indocyanine green (ICG), a fluorochrome that green stains the structures where it is present, is injected during surgery. This study proposes a novel method based on deep learning algorithms for quantifying the level of blood perfusion in anastomosis. Firstly, with a deep learning algorithm based on the U-Net, models capable of automatically segmenting the intestine from the surgical videos were generated. Secondly, blood perfusion level, from the already segmented video frames, was quantified. The frames were characterized using textures, precisely nine first- and second-order statistics, and then two experiments were carried out. In the first experiment, the differences in the perfusion between the two-anastomosis parts were determined, and in the second, it was verified that the ICG variation could be captured through the textures. The best model when segmenting has an accuracy of 0.92 and a dice coefficient of 0.96. It is concluded that segmentation of the bowel using the U-Net was successful, and the textures are appropriate descriptors for characterization of the blood perfusion in the images where ICG is present. This might help to predict whether postoperative complications will occur during surgery, enabling clinicians to act on this information.

The Role of Indocyanine Near-Infrared Fluorescence in Colorectal Surgery

PURPOSES

The aim of this study was to evaluate the importance of Indocyanine Green in control of anastomosis perfusion and on anastomotic leakage rates during laparoscopic and robotic colorectal procedures.

METHODS

A retrospective review of patients who underwent elective minimally invasive surgery for colorectal cancer from 1 January 2018 to 31 December 2020 was performed. All patients underwent Near-Infrared Fluorescence-Indocyanine Green system in two moments: before performing the anastomosis and after completing the anastomotic procedure. Primary outcomes were the rate of intraoperative change in the surgical resection due to an inadequate vascularization and the rate of postoperative anastomotic leakage. Secondary outcomes were the postoperative complications, both medical and surgical (intra-abdominal bleeding, anastomotic leakage).

RESULTS

Our analysis included 93 patients. Visible fluorescence was detected in 100% of the cases. In 7 patients (7.5%), the planned site of resection was changed due to inadequate perfusion. The mean extension of the surgical resection in these 7 patients was 2.2 ± 0.62. Anastomotic leakage occurred in 2 patients (2.1%). Other complications included 8 postoperative bleedings (8.6%) and 1 pulmonary thromboembolism.

CONCLUSIONS

The intraoperative use of Near-Infrared Fluorescence-Indocyanine Green in colorectal surgery is safe, feasible, and associated with a substantial reduction in postoperative anastomotic leakage rate.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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