Indocyanine green-based fluorescence imaging in visceral and hepatobiliary and pancreatic surgery: State of the art and future directions

Indocyanine Green and Hepatobiliary Surgery: An Overview of the Current Literature

Indocyanine green (ICG) is an inert polypeptide that almost totally binds to high molecular weight plasma proteins; it is cleared by the hepatocytes and directly excreted into the bile with a half-life of about 3-5 minutes. Specific systems are required to see fluorescent images. The use of this dye has been reported in different surgical specialties, and the applications in hepatobiliary surgery are widening. Being firstly used to evaluate the preoperative liver function, intra- and postoperative dynamic checking of hepatic activity has been reported and integrated within perioperative protocols allowing a tailored treatment allocation. Intravenous injection (IV) or injection into the gallbladder can ease difficult cholecystectomy. Biliary leakage detection could be enhanced by IV ICG injection. Although with some contrasting results, the use of ICG for both delineating the limits of the resection and tumor-enhanced visualization was demonstrated to improve short- and long-term outcomes. Although the lack of strong evidence still precludes the introduction of this tool in clinical practice, it harbors great potential in liver 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.

Can near-infrared imaging distinguish a gelatin-based matrix granuloma from a malignancy in a kidney?

Aim: Differentiating granulomas from cancerous tissue poses a significant challenge in upper urinary tract surgery. We present the case of a 62-year-old male with a gelatin-based matrix (SurgifloTM) granuloma in the kidney following renal cyst decortication eight years earlier.Methods: Contrast-enhanced abdominal tomography revealed a Bosniak type-4 cyst at the previous operation site. The patient underwent laparoscopic partial nephrectomy with near-infrared imaging.Results: The lesion presented as hypofluorescent relative to normal kidney tissue. Histopathological examination revealed a foreign body granuloma due to unabsorbed Surgiflo.Conclusion: The fluorescence pattern could not distinguish a Surgiflo granuloma from a malignant lesion of the kidney.

[Status Quo of Surgical Navigation]

Surgical navigation, also referred to as computer-assisted or image-guided surgery, is a technique that employs a variety of methods - such as 3D imaging, tracking systems, specialised software, and robotics to support surgeons during surgical interventions. These emerging technologies aim not only to enhance the accuracy and precision of surgical procedures, but also to enable less invasive approaches, with the objective of reducing complications and improving operative outcomes for patients. By harnessing the integration of emerging digital technologies, surgical navigation holds the promise of assisting complex procedures across various medical disciplines. In recent years, the field of surgical navigation has witnessed significant advances. Abdominal surgical navigation, particularly endoscopy, laparoscopic, and robot-assisted surgery, is currently undergoing a phase of rapid evolution. Emphases include image-guided navigation, instrument tracking, and the potential integration of augmented and mixed reality (AR, MR). This article will comprehensively delve into the latest developments in surgical navigation, spanning state-of-the-art intraoperative technologies like hyperspectral and fluorescent imaging, to the integration of preoperative radiological imaging within the intraoperative setting.

Recent advances in computerized imaging and its vital roles in liver disease diagnosis, preoperative planning, and interventional liver surgery: A review

The earliest and most accurate detection of the pathological manifestations of hepatic diseases ensures effective treatments and thus positive prognostic outcomes. In clinical settings, screening and determining the extent of a pathology are prominent factors in preparing remedial agents and administering appropriate therapeutic procedures. Moreover, in a patient undergoing liver resection, a realistic preoperative simulation of the subject-specific anatomy and physiology also plays a vital part in conducting initial assessments, making surgical decisions during the procedure, and anticipating postoperative results. Conventionally, various medical imaging modalities, e.g., computed tomography, magnetic resonance imaging, and positron emission tomography, have been employed to assist in these tasks. In fact, several standardized procedures, such as lesion detection and liver segmentation, are also incorporated into prominent commercial software packages. Thus far, most integrated software as a medical device typically involves tedious interactions from the physician, such as manual delineation and empirical adjustments, as per a given patient. With the rapid progress in digital health approaches, especially medical image analysis, a wide range of computer algorithms have been proposed to facilitate those procedures. They include pattern recognition of a liver, its periphery, and lesion, as well as pre- and postoperative simulations. Prior to clinical adoption, however, software must conform to regulatory requirements set by the governing agency, for instance, valid clinical association and analytical and clinical validation. Therefore, this paper provides a detailed account and discussion of the state-of-the-art methods for liver image analyses, visualization, and simulation in the literature. Emphasis is placed upon their concepts, algorithmic classifications, merits, limitations, clinical considerations, and future research trends.

Cobalt ferrite nanoparticle for the elimination of CD133+CD44+ and CD44+CD24-, in breast and skin cancer stem cells, using non-ionizing treatments

Background

Cancer stem cells (CSCs) are the most challenging issue in cancer treatment, because of their high resistance mechanisms, that can cause tumor recurrence after common cancer treatments such as drug and radiation based therapies, and the insufficient efficiency of common treatments in CSCs removal and the recurrence of tumors after these treatments, it is essential to consider other methods, including non-ionizing treatments likes light-based treatments and magnetic hyperthermia (MHT).

Method and material

After synthesis, characterization and investigation, the toxicity of novel on A375 and MAD-MB-231 cell lines, magnetic hyperthermia and light-based treatments were applied. MTT assay and flow cytometry was employed to determine cell survival. the influence of combination therapy on CD44 + CD24-and CD133 + CD44+ cell population, Comparison and evaluation of combination treatments was done respectively using Combination Indices (CIs).

Result

The final nanoparticle has a high efficiency in producing hydroxyl radicals and generating heat in MHT. According to CIs, we can conclude that combined using of light-based treatment and MHT in the presence of final synthesized nanoparticle have synergistic effect and a high ability to reduce the population of stem cells in both cell lines compared to single treatments.

Conclusion

In this study a novel multi-functional nanoplatform acted well in dual and triple combined treatments, and showed a good performance in the eradication of CSCs, in A375 and MAD-MB-231 cell lines.

Application of near-infrared fluorescence imaging in theranostics of gastrointestinal tumors

Gastrointestinal cancers have become an important cause of cancer-related death in humans. Improving the early diagnosis rate of gastrointestinal tumors and improving the effect of surgical treatment can significantly improve the survival rate of patients. The conventional diagnostic method is high-definition white-light endoscopy, which often leads to missed diagnosis. For surgical treatment, intraoperative tumor localization and post-operative anastomotic state evaluation play important roles in the effect of surgical treatment. As a new imaging method, near-infrared fluorescence imaging (NIRFI) has its unique advantages in the diagnosis and auxiliary surgical treatment of gastrointestinal tumors due to its high sensitivity and the ability to image deep tissues. In this review, we focus on the latest advances of NIRFI technology applied in early diagnosis of gastrointestinal tumors, identification of tumor margins, identification of lymph nodes, and assessment of anastomotic leakage. In addition, we summarize the advances of NIRFI systems such as macro imaging and micro imaging systems, and also clearly describe the application process of NIRFI from system to clinical application, and look into the prospect of NIRFI applied in the theranostics of gastrointestinal tumors.

The magic mirror: a novel intraoperative monitoring method for parathyroid glands

The accurate detection of parathyroid glands (PGs) during surgery is of great significance in thyroidectomy and parathyroidectomy, which protects the function of normal PGs to prevent postoperative hypoparathyroidism and the thorough removal of parathyroid lesions. Existing conventional imaging techniques have certain limitations in the real-time exploration of PGs. In recent years, a new, real-time, and non-invasive imaging system known as the near-infrared autofluorescence (NIRAF) imaging system has been developed to detect PGs. Several studies have confirmed that this system has a high parathyroid recognition rate and can reduce the occurrence of transient hypoparathyroidism after surgery. The NIRAF imaging system, like a magic mirror, can monitor the PGs during surgery in real time, thus providing great support for surgeries. In addition, the NIRAF imaging system can evaluate the blood supply of PGs by utilizing indocyanine green (ICG) to guide surgical strategies. The NIRAF imaging system and ICG complement each other to protect normal parathyroid function and reduce postoperative complications. This article reviews the effectiveness of the NIRAF imaging system in thyroidectomies and parathyroidectomies and briefly discusses some existing problems and prospects for the future.

Fluorescence-guided surgery: comprehensive review

BACKGROUND

Despite significant improvements in preoperative workup and surgical planning, surgeons often rely on their eyes and hands during surgery. Although this can be sufficient in some patients, intraoperative guidance is highly desirable. Near-infrared fluorescence has been advocated as a potential technique to guide surgeons during surgery.

METHODS

A literature search was conducted to identify relevant articles for fluorescence-guided surgery. The literature search was performed using Medical Subject Headings on PubMed for articles in English until November 2022 and a narrative review undertaken.

RESULTS

The use of invisible light, enabling real-time imaging, superior penetration depth, and the possibility to use targeted imaging agents, makes this optical imaging technique increasingly popular. Four main indications are described in this review: tissue perfusion, lymph node assessment, anatomy of vital structures, and tumour tissue imaging. Furthermore, this review provides an overview of future opportunities in the field of fluorescence-guided surgery.

CONCLUSION

Fluorescence-guided surgery has proven to be a widely innovative technique applicable in many fields of surgery. The potential indications for its use are diverse and can be combined. The big challenge for the future will be in bringing experimental fluorophores and conjugates through trials and into clinical practice, as well as validation of computer visualization with large data sets. This will require collaborative surgical groups focusing on utility, efficacy, and outcomes for these techniques.

Indocyanine green fluorescence imaging to localize insulinoma and provide three-dimensional demarcation for laparoscopic enucleation: a retrospective single-arm cohort study

BACKGROUND

Indocyanine green (ICG) fluorescence imaging is a new technology that can improve the real-time location of tumor edges and small nodules during surgery. However, no study has investigated its application in laparoscopic insulinoma enucleation. This study aimed to evaluate the feasibility and accuracy of this method for intraoperative localization of insulinomas and margin assessment during laparoscopic insulinoma enucleation.

MATERIALS AND METHODS

Eight patients who underwent laparoscopic insulinoma enucleation from October 2016 to June 2022 were enrolled. Two methods of ICG administration, ICG dynamic perfusion and three-dimensional (3D) demarcation staining, were utilized in the laparoscopic insulinoma enucleation. Tumor-to-background ratio (TBR) and histopathologic analysis were used to evaluate the feasibility and accuracy of these novel navigation methods in laparoscopic insulinoma enucleation.

RESULTS

All eight enrolled patients underwent both ICG dynamic perfusion and 3D demarcation staining. ICG dynamic perfusion images were available for six of them, among which five tumors could be recognized by TBR (largest TBR in each case 4.42±2.76), while the other could be distinguished by the disordered blood vessels in the tumor area. Seven out of eight specimens had successful 3D demarcation staining (TBR 7.62±2.62). All wound bed margins had negative frozen sections and final histopathologic diagnoses.

CONCLUSIONS

ICG dynamic perfusion may be helpful in observing the abnormal vascular perfusion of tumors, providing similar functionality to intraoperative real-time angiography. ICG injection under the tumor pseudocapsule may be a useful method for acquiring real-time, 3D demarcation for the resection of insulinoma.

Real-time quantification of intestinal perfusion and arterial versus venous occlusion using laser speckle contrast imaging in porcine model

PURPOSE

Real-time intraoperative perfusion assessment may reduce anastomotic leaks. Laser speckle contrast imaging (LSCI) provides dye-free visualization of perfusion by capturing coherent laser light scatter from red blood cells and displays perfusion as a colormap. Herein, we report a novel method to precisely quantify intestinal perfusion using LSCI.

METHODS

ActivSight™ is an FDA-cleared multi-modal visualization system that can detect and display perfusion via both indocyanine green imaging (ICG) and LSCI in minimally invasive surgery. An experimental prototype LSCI perfusion quantification algorithm was evaluated in porcine models. Porcine small bowel was selectively devascularized to create regions of perfused/watershed/ischemic bowel, and progressive aortic inflow/portal vein outflow clamping was performed to study arterial vs. venous ischemia. Continuous arterial pressure was monitored via femoral line.

RESULTS

LSCI perfusion colormaps and quantification distinguished between perfused, watershed, and ischemic bowel in all vascular control settings: no vascular occlusion (p < 0.001), aortic occlusion (p < 0.001), and portal venous occlusion (p < 0.001). LSCI quantification demonstrated similar levels of ischemia induced both by states of arterial inflow and venous outflow occlusion. LSCI-quantified perfusion values correlated positively with higher mean arterial pressure and with increasing distance from ischemic bowel.

CONCLUSION

LSCI relative perfusion quantification may provide more objective real-time assessment of intestinal perfusion compared to conventional naked eye assessment by quantifying currently subjective gradients of bowel ischemia and identifying both arterial/venous etiologies of ischemia.

Use of fluorescence imaging and indocyanine green during laparoscopic cholecystectomy: Results of an international Delphi survey

BACKGROUND

Published empirical data have increasingly suggested that using near-infrared fluorescence cholangiography during laparoscopic cholecystectomy markedly increases biliary anatomy visualization. The technology is rapidly evolving, and different equipment and doses may be used. We aimed to identify areas of consensus and nonconsensus in the use of incisionless near-infrared fluorescent cholangiography during laparoscopic cholecystectomy.

METHODS

A 2-round Delphi survey was conducted among 28 international experts in minimally invasive surgery and near-infrared fluorescent cholangiography in 2020, during which respondents voted on 62 statements on patient preparation and contraindications (n = 12); on indocyanine green administration (n = 14); on potential advantages and uses of near-infrared fluorescent cholangiography (n = 18); comparing near-infrared fluorescent cholangiography with intraoperative x-ray cholangiography (n = 7); and on potential disadvantages of and required training for near-infrared fluorescent cholangiography (n = 11).

RESULTS

Expert consensus strongly supports near-infrared fluorescent cholangiography superiority over white light for the visualization of biliary structures and reduction of laparoscopic cholecystectomy risks. It also offers other advantages like enhancing anatomic visualization in obese patients and those with moderate to severe inflammation. Regarding indocyanine green administration, consensus was reached that dosing should be on a milligrams/kilogram basis, rather than as an absolute dose, and that doses >0.05 mg/kg are necessary. Although there is no consensus on the optimum preoperative timing of indocyanine green injections, the majority of participants consider it important to administer indocyanine green at least 45 minutes before the procedure to decrease the light intensity of the liver.

CONCLUSION

Near-infrared fluorescent cholangiography experts strongly agree on its effectiveness and safety during laparoscopic cholecystectomy and that it should be used routinely, but further research is necessary to establish optimum timing and doses for indocyanine green.

Theoretical Study on Spectrum and Luminescence Mechanism of Indocyanine Green Dye Based on Density Functional Theory (DFT)

Indocyanine green is a great near-infrared fluorescence with good luminescent properties and important medical applications. In this paper, the theoretical spectrum and orbital model of its molecular level are established. The two most probable conformations were studied, and their energies, vibrational spectra, UV-Vis absorption spectra, frontier molecular orbitals (HOMO and LUMO), and energy gaps were obtained by density functional theory (DFT) calculations, respectively. This provides a theoretical and design basis for the development of novel dyes similar to indocyanine green dyes and a reference case for improved application methods and synthetic predesign of novel fluorescent dyes.

Systematic review, meta-analysis and single-centre experience of the diagnostic accuracy of intraoperative near-infrared indocyanine green-fluorescence in detecting pancreatic tumours

BACKGROUND

During pancreatic resections assessing tumour boundaries and identifying the ideal resection margins can be challenging due to the associated pancreatic gland inflammation and texture. This is particularly true in the context of minimally invasive surgery, where there is a very limited or absent tactile feedback. Indocyanine green (ICG) fluorescence imaging can assist surgeons by simply providing valuable real-time intraoperative information at low cost with minimal side effects. This meta-analysis summarises the available evidence on the use of near-infrared fluorescence imaging with ICG for the intraoperative visualization of pancreatic tumours (PROSPERO ID: CRD42021247203).

METHODS

MEDLINE, Embase, and Web Of Science electronic databases were searched to identify manuscripts where ICG was intravenously administered prior to or during pancreatic surgery and reporting the prevalence of pancreatic lesions visualised through fluorescence imaging.

RESULTS

Six studies with 7 series' reporting data on 64 pancreatic lesions were included in the analysis. MINOR scores ranged from 6 to 10, with a median of 8. The most frequent indications were pancreatic adenocarcinoma and neuroendocrine tumours. In most cases (67.2%) ICG was administered during surgery. ICG fluorescence identified 48/64 lesions (75%) with 81.3% accuracy, 0.788 (95%CI 0.361-0.961) sensitivity, 1 (95%CI 0.072-1) specificity and positive predictive value of 0.982 (95%CI 0.532-1). In line with the literature, ICG fluorescence identified 5/6 (83.3%) of pancreatic lesions during robotic pancreatic resections performed at our Institution.

CONCLUSION

This meta-analysis is the first summarising the results of ICG immunofluorescence in detecting pancreatic tumours during surgery, showing good accuracy. Additional research is needed to define optimal ICG administration strategies and fluorescence intensity cut-offs.

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 colonic perfusion demonstration following robotic da Vinci X inferior mesenteric artery ligation for the treatment of type II endoleak

Background

We describe the technical operative details of the robotic repair of a type II endoleak (T2E) following endovascular abdominal aortic aneurysm repair (EVAR). We demonstrate that indocyanine green (ICG) can be used intra‐operatively to demonstrate perfusion of the colon following ligation of the inferior mesenteric artery (IMA) vessel feeding the aneurysm sac.

Methods

A 74‐year old male underwent EVAR for a 5.8 cm infra‐renal abdominal aortic aneurysm using an E‐Tegra, Jotec Device (JOTEC Gmb, Lotzenäcker 23,D‐72379 Hechingen). Surveillance contrast CT (CTA) over the ensuing 30 months confirmed progressive sac expansion.

Results

ICG confirmed colonic perfusion via the marginals after IMA ligation. Total operative time 56 min < 50 mls blood loss and 1‐day hospital stay. 3‐month follow‐up: CTA and ultrasound demonstrated complete resolution of T2E and adequately perfused colon.

Conclusion

A total robotic approach can be performed safely with intra‐operative ICG used to demonstrate colonic perfusion as an added safety measure.

Morbidity analysis of left hepatic trisectionectomy for hepatobiliary disease and live donor

BACKGROUND

Despite remarkable advances in surgical techniques and perioperative management, left hepatic trisectionectomy (LHT) remains a challenging procedure with a somewhat high postoperative morbidity rate compared with less-extensive resections. This study aimed to analyze the short- and long-term outcomes of LHT and identify factors associated with the postoperative morbidity of this technically demanding surgical procedure.

METHODS

The medical records of 53 patients who underwent LHT between June 2005 and October 2019 at a single institution were retrospectively reviewed. The independent prognostic factor of postoperative morbidity was analyzed using the logistic regression model.

RESULTS

Hepatocellular carcinoma was the most common indication for surgery (n = 21), followed by hilar cholangiocarcinoma (n = 14), intrahepatic cholangiocarcinoma (n = 10), and other pathologies (including colorectal liver metastasis, hepatolithiasis, gallbladder cancer, living donor, hemangioma, and multilocular biliary cyst; n = 8). The rates of postoperative morbidities of Clavien-Dindo grade 3 or higher and 90-day mortality were 39.6% and 1.9%, respectively. The 1-, 3-, and 5-year overall survival rates were 81.1%, 61.4%, and 44.6%, respectively. Multivariate analysis revealed that preoperative jaundice [hazard ratio (HR) = 6.15, 95% confidence interval (CI): 1.57-24.17, P = 0.009] and operative time > 420 min (HR = 4.66, 95% CI: 1.27-17.17, P = 0.021) were independent predictors of postoperative morbidity.

CONCLUSIONS

The in-hospital mortality of LHT surgery can be minimalized by a reliable preoperative evaluation of liver function and selection of the dominant anatomic features of right posterior sector, active and appropriate preoperative management for obstructive cholangitis and compensatory hypertrophy of the future remnant posterior sector, and the experience of the surgeon.

Fluorescence Guided Cholecystectomy by a Single Group: Initial 47 Procedures Experience in Mexico

Introduction

Fluorescence guided surgery (FGS) for biliary surgery uses indocyanine green (ICG), a specific dye that is eliminated almost exclusively by the liver and biliary system, making it very useful for an adequate and safe visualization of biliary tract structures.

Methods

We present our experience with FGS for cholecystectomy multiport and single port, including all patients older than 18 years of age, with diagnosis of cholecystitis (acute and chronic), from October 18, 2018 to December 30, 2021.

Results

A total of 47 patients were managed with FGS cholecystectomy, mean age was 61.2 (± 17.7) years, 31 (65.9%) were female and 16 (34.1%) males. Twenty-four (51.1%) were emergency procedures, due to acute cholecystitis, of which 10 (41.7%) presented with an infected gallbladder (Parkland 3 to 5) and three (12.5%) presented with related acute pancreatitis, the remaining 23 (48.9%) cases were elective surgeries, due to chronic cholecystitis. Visualization of laparoscopic fluorescence of the biliary ducts was achieved in 45 of the 47 patients (95.7%). Mean time for biliary tract structures visual identification was 8 minutes and 40 seconds (± 7 minutes, 20 seconds), fluorescence allowed the visualization of biliary tract anatomical variants in two patients.

Discussion

The reported rate of biliary structures visualization using ICG is relatively variable, ranging from 25% to 100%, in our group it was 95.7% due to our protocol.

Conclusions

ICG utilization for cholecystectomy is very useful and helps for a safe procedure even in difficult surgeries, we believe that it should be used in everyday practice.

Navigated liver surgery: State of the art and future perspectives

BACKGROUND

In recent years, the development of digital imaging technology has had a significant influence in liver surgery. The ability to obtain a 3-dimensional (3D) visualization of the liver anatomy has provided surgery with virtual reality of simulation 3D computer models, 3D printing models and more recently holograms and augmented reality (when virtual reality knowledge is superimposed onto reality). In addition, the utilization of real-time fluorescent imaging techniques based on indocyanine green (ICG) uptake allows clinicians to precisely delineate the liver anatomy and/or tumors within the parenchyma, applying the knowledge obtained preoperatively through digital imaging. The combination of both has transformed the abstract thinking until now based on 2D imaging into a 3D preoperative conception (virtual reality), enhanced with real-time visualization of the fluorescent liver structures, effectively facilitating intraoperative navigated liver surgery (augmented reality).

DATA SOURCES

A literature search was performed from inception until January 2021 in MEDLINE (PubMed), Embase, Cochrane library and database for systematic reviews (CDSR), Google Scholar, and National Institute for Health and Clinical Excellence (NICE) databases.

RESULTS

Fifty-one pertinent articles were retrieved and included. The different types of digital imaging technologies and the real-time navigated liver surgery were estimated and compared.

CONCLUSIONS

ICG fluorescent imaging techniques can contribute essentially to the real-time definition of liver segments; as a result, precise hepatic resection can be guided by the presence of fluorescence. Furthermore, 3D models can help essentially to further advancing of precision in hepatic surgery by permitting estimation of liver volume and functional liver remnant, delineation of resection lines along the liver segments and evaluation of tumor margins. In liver transplantation and especially in living donor liver transplantation (LDLT), 3D printed models of the donor's liver and models of the recipient's hilar anatomy can contribute further to improving the results. In particular, pediatric LDLT abdominal cavity models can help to manage the largest challenge of this procedure, namely large-for-size syndrome.

The Role of Indocyanine Green Fluorescence in Rectal Cancer Robotic Surgery: A Narrative Review

Background: In rectal cancer surgery, anastomotic leakage (AL) remains the most feared complication, with a frequency of up to 30% in non-high-volume centers. The preservation of proper vascularization is a key factor for successful anastomosis. The use of fluorescence with indocyanine green (ICG) as an intraoperative method to verify optimal perfusion is becoming an interesting tool in rectal surgery. Today, robotic surgery, together with the use of the intraoperative evaluation of the perfusion with ICG, could be a real strategy to deal with AL, allowing for a more delicate and less traumatic surgical technique. This strategy may allow for an extremely accurate surgery, and for optimal control of the proper vascularization of the rectum. Methods: The purpose of this descriptive review is to analyze the impact of fluorescence and robotic surgery on short-term surgical outcomes for rectal cancer. Results: We performed a systematic literature search using the PubMed, Embase and Cochrane library databases. The primary endpoints were to evaluate the application of ICG fluorescence in robotic rectal surgery and the rate of anastomotic leakage when using these technological implementations. The secondary endpoints were to evaluate the dosage of ICG and the timing of application by different surgeons. Conclusions: ICG fluorescence is an inexpensive and quick method to assess bowel perfusion, providing immediate feedback to the surgeon, even if its role has not been proven. A quantitative system must be systematically introduced to minimize the subjectiveness of the visualized image.

Tumor-Specific Imaging with Angiostamp800 or Bevacizumab-IRDye 800CW Improves Fluorescence-Guided Surgery over Indocyanine Green in Peritoneal Carcinomatosis

Complete surgical removal of lesions improves survival of peritoneal carcinomatosis and can be enhanced by intraoperative near-infrared fluorescence imaging. Indocyanine green (ICG) is the only near-infrared fluorescent dye approved for clinical use, but it lacks specificity for tumor cells, highlighting the need for tumor-selective targeting agents. We compared the tumor-specific near-infrared fluorescent probes Bevacizumab-IRDye 800CW and Angiostamp800, which target tumor angiogenesis and cancer cells, to ICG for fluorescence-guided surgery in peritoneal carcinomatosis of ovarian origin. The probes were administered to mice with orthotopic peritoneal carcinomatosis prior to conventional and fluorescence-guided surgery. The influence of neoadjuvant chemotherapy was also assessed. Conventional surgery removed 88.0 ± 1.2% of the total tumor load in mice. Fluorescence-guided surgery allowed the resection of additional nodules, enhancing the total tumor burden resection by 9.8 ± 0.7%, 8.5 ± 0.8%, and 3.9 ± 1.2% with Angiostamp800, Bevacizumab-IRDye 800CW and ICG, respectively. Interestingly, among the resected nodules, 15% were false-positive with ICG, compared to only 1.4% with Angiostamp800 and 3.5% with Bevacizumab-IRDye 800CW. Furthermore, conventional surgery removed only 69.0 ± 3.9% of the total tumor burden after neoadjuvant chemotherapy. Fluorescence-guided surgery with Angiostamp800 and Bevacizumab-IRDye 800CW increased the total tumor burden resection to 88.7 ± 4.3%, whereas ICG did not improve surgery at all. Bevacizumab-IRDye 800CW and Angiostamp800 better detect ovarian tumors and metastases than the clinically used fluorescent tracer ICG, and can help surgeons completely remove tumors, especially after surgery neoadjuvant chemotherapy.

Consensus Conference Statement on the General Use of Near-infrared Fluorescence Imaging and Indocyanine Green Guided Surgery: Results of a Modified Delphi Study

BACKGROUND

In recent decades, the use of near-infrared light and fluorescence-guidance during open and laparoscopic surgery has exponentially expanded across various clinical settings. However, tremendous variability exists in how it is performed.

OBJECTIVE

In this first published survey of international experts on fluorescence-guided surgery, we sought to identify areas of consensus and nonconsensus across 4 areas of practice: fundamentals; patient selection/preparation; technical aspects; and effectiveness and safety.

METHODS

A Delphi survey was conducted among 19 international experts in fluorescence-guided surgery attending a 1-day consensus meeting in Frankfurt, Germany on September 8th, 2019. Using mobile phones, experts were asked to anonymously vote over 2 rounds of voting, with 70% and 80% set as a priori thresholds for consensus and vote robustness, respectively.

RESULTS

Experts from 5 continents reached consensus on 41 of 44 statements, including strong consensus that near-infrared fluorescence-guided surgery is both effective and safe across a broad variety of clinical settings, including the localization of critical anatomical structures like vessels, detection of tumors and sentinel nodes, assessment of tissue perfusion and anastomotic leaks, delineation of segmented organs, and localization of parathyroid glands. Although the minimum and maximum safe effective dose of ICG were felt to be 1 to 2 mg and >10 mg, respectively, there was strong consensus that determining the optimum dose, concentration, route and timing of ICG administration should be an ongoing research focus.

CONCLUSIONS

Although fluorescence imaging was almost unanimously perceived to be both effective and safe across a broad range of clinical settings, considerable further research remains necessary to optimize its use.

The iGreenGO Study: The Clinical Role of Indocyanine Green Imaging Fluorescence in Modifying the Surgeon’s Conduct During the Surgical Treatment of Advanced Gastric Cancer—Study Protocol for an International Multicenter Prospective Study

Background

The near-infrared/indocyanine green imaging fluorescence (NIR/ICG) technology is showing promising results in several fields of surgical oncology. The clinical value of NIR/ICG technology in the surgical treatment of advanced gastric cancer (AGC) is not clearly established.

Methods

This is the protocol of the “iGreenGO” (indocyanine Green Gastric Observation) Study, a national prospective multicenter study. Western patients who undergo curative-intent gastrectomy with D2 lymphadenectomy for AGC constitute the study cohort. All the patients undergo preoperative upper gastrointestinal endoscopy for submucosal peritumoral ICG injection at the most 20 h before surgery. Intraoperative endoscopic injection before starting surgical dissection is also allowed. The primary endpoint is the “change in the surgical conduct” (CSC), i.e., the need to perform further dissection after intraoperative NIR/ICG technology activation at the end of D2 lymphadenectomy. Secondary endpoints include the pattern of abdominal fluorescence distribution according to tumor and patient characteristics, the preoperative clinical variables potentially associated with CSC, and the incidence of stage migration due to NIR/ICG application.

Discussion

The iGreenGO Study is the first study to investigate the clinical role of NIR/ICG technology for the surgical treatment of AGC in a large cohort of Western patients. Results from the present study can further clarify the role of NIR/ICG technology in surgical lymphadenectomy for AGC.

Role of Indocyanine Green Fluorescence Imaging in Minimally Invasive Resection of Colorectal Liver Metastases

Indocyanine green (ICG) fluorescence imaging is an easy and reproducible method to detect hepatic lesions, both primary and metastatic. This review reports the potential benefits of this technique as a tactile mimicking visual tool and a navigator guide in minimally invasive liver resection of colorectal liver metastases (CRLM). PubMed and MEDLINE databases were searched for studies reporting the use of intravenous injection of ICG before minimally invasive surgery for CLRM. The search was performed for publications reported from the first study in 2014 to April 2021. The final review included 13 articles: 6 prospective cohort studies, 1 retrospective cohort study, 3 case series, 1 case report, 1 case-matched study, and 1 clinical trial registry. The administered dose ranged between 0.3 and 0.5 mg/kg, while timing ranged between 1 and 14 days before surgery. CRLM detection rate ranged between 30.3% and 100% with preoperative imaging (abdominal computed tomography/magnetic resonance imaging), between 93.3 and 100% with laparoscopic ultrasound, between 57.6% and 100% with ICG fluorescence, and was 100% with combined modalities (ICG and laparoscopic ultrasound) with weighted averages of 77.42%, 95.97%, 79.03%, and 100%, respectively. ICG fusion imaging also allowed to detect occult small-sized lesions, not diagnosed preoperatively. In addition, ICG is effective in real-time assessment of surgical margins by evaluating the integrity of the fluorescent rim around the CRLM.

Intraoperative reperfusion assessment of human pancreas allografts using hyperspectral imaging (HSI)

Background

The most common causes of early graft loss in pancreas transplantation are insufficient blood supply and leakage of the intestinal anastomosis. Therefore, it is critical to monitor graft perfusion and oxygenation during the early post-transplant period. The goal of our pilot study was to evaluate the utility of hyperspectral imaging (HSI) in monitoring the microcirculation of the graft and adequate perfusion of the intestinal anastomosis during pancreatic allotransplantation.

Methods

We imaged pancreatic grafts and intestinal anastomosis in real-time in three consecutive, simultaneous pancreas-kidney transplantations using the TIVITA^® HSI system. Further, the intraoperative oxygen saturation (StO₂), tissue perfusion (near-infrared perfusion index, NIR), organ hemoglobin index (OHI), and tissue water index (TWI) were measured 15 minutes after reperfusion by HSI.

Results

All pancreas grafts showed a high and homogeneous StO₂ (92.6%±10.45%). Intraoperative HSI analysis of the intestinal anastomosis displayed significant differences of StO₂ (graft duodenum 67.46%±5.60% vs. recipient jejunum: 75.93%±4.71%, P<0.001) and TWI {graft duodenum: 0.63±0.09 [I (Index)] vs. recipient jejunum: 0.72±0.09 [I], P<0.001}. NIR and OHI did not display remarkable differences {NIR duodenum: 0.68±0.06 [I] vs. NIR jejunum: 0.69±0.04 [I], P=0.747; OHI duodenum: 0.70±0.12 [I] vs. OHI jejunum: 0.68±0.13 [I], P=0.449}. All 3 patients had an uneventful postoperative course with one displaying a Banff 1a rejection which was responsive to steroid treatment.

Conclusions

Our study shows that contact-free HSI has potential utility as a novel tool for real-time monitoring of human pancreatic grafts after reperfusion, which could improve the outcome of pancreas transplantation. Further investigations are required to determine the predictive value of intraoperative HSI imaging.

Laparoscopic lymph node biopsy for lymphoma with a novel use of indocyanine green fluorescence in a 66-year-old male patient

Introduction

Indocyanine green (ICG) near-infrared fluorescence is primarily employed in detecting Intraoperative sentinel lymph node (SLN) mapping or to evaluate the extent of radical lymphadenectomy mainly in colo-rectal and gastric cancer. To date there are no reports indicating the use of this dye to detect pathologic lymphatic tissue when a lymph node biopsy for suspected lymphoproliferative disease is performed.

Presentation of case

A 66-year-old male patient was admitted to the hospital for severe pain of left renal colic type. A computed tomography (CT) scan and a positron emission tomography (PET) showed a left hydroureteronephrosis due to ureter compression by paraortic solid tissue of lymphomatous aspect with a standardized uptake value (SUV) of 15. Multiple lymphadenopathies on paracaval, para-aortic and common iliac sites were present as well.

Discussion

A laparoscopic lymph node biopsy (LLB) was planned for diagnostic purposes. After induction of anesthesia a ICG solution was injected Intradermally at both inguinal regions. At laparoscopy a complete visualization of the pathologic lymphnodes was achieved, enabling incisional biopsies of the lymphomatous mass. Histopathological examination showed an extranodal localization of an aggressive B-cell non-Hodgkin lymphoma.

Conclusion

ICG-fluorescence seems to offer a simple and safe method for pathologic lymph node detection. LLB in the suspicion of intra abdominal lymphoma can largely take advantage by this novel opportunity not yet tested to date. More studies with large case series are needed to confirm the efficacy of ICG-fluorescence for detecting pathologic lymph nodes.

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First report in literature concerning the use of indocyanine green (ICG) for laparoscopic lymph node biopsy

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Periaortic and iliac lymph nodes visualized at PET as pathological, at laparoscopy turned out to be stained up by ICG.

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Deep lymph nodes staining with ICG is possible by means of a preoperative injection of an ICG solution into the inguinal regions.

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ICG-fluorescence seems to offer a useful, expeditious, and easy reproductible method for pathologic lymph node [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19]] laparoscopic lymph node biopsy (LLB).

OUP accepted manuscript

To date, there are no reports indicating the use of indocyanine green (ICG) fluorescence to detect pathologic lymphatic tissue when a laparoscopic lymph node biopsy (LLB) for suspected new or recurrent lymphoma is performed. We present the case of a 72-year-old female patient admitted for suspicion of recurrent lymphoma. A preoperative imaging work-up showed solid tissue enveloping the terminal portion of the abdominal aorta with a standardized uptake value (SUV) of 10. Therefore, an LLB was planned. After induction of anesthesia, a ICG solution was injected intravenously and subcutaneously at both inguinal regions. At laparoscopy, a complete visualization of the pathologic lymph nodes was achieved, enabling an incisional biopsy of the lymphomatous mass. LLB with ICG-fluorescence offers a simple and safe method for pathologic lymph node detection in the suspicion of intra-abdominal lymphoma. More studies with large case series are needed to confirm the efficacy of this application.

Novel Intraoperative Imaging of Gastric Tube Perfusion during Oncologic Esophagectomy—A Pilot Study Comparing Hyperspectral Imaging (HSI) and Fluorescence Imaging (FI) with Indocyanine Green (ICG)

Background: Novel intraoperative imaging techniques, namely, hyperspectral (HSI) and fluorescence imaging (FI), are promising with respect to reducing severe postoperative complications, thus increasing patient safety. Both tools have already been used to evaluate perfusion of the gastric conduit after esophagectomy and before anastomosis. To our knowledge, this is the first study evaluating both modalities simultaneously during esophagectomy. Methods: In our pilot study, 13 patients, who underwent Ivor Lewis esophagectomy and gastric conduit reconstruction, were analyzed prospectively. HSI and FI were recorded before establishing the anastomosis in order to determine its optimum position. Results: No anastomotic leak occurred during this pilot study. In five patients, the imaging methods resulted in a more peripheral adaptation of the anastomosis. There were no significant differences between the two imaging tools, and no adverse events due to the imaging methods or indocyanine green (ICG) injection occurred. Conclusions: Simultaneous intraoperative application of both modalities was feasible and not time consuming. They are complementary with regard to the ideal anastomotic position and may contribute to better surgical outcomes. The impact of their simultaneous application will be proven in consecutive prospective trials with a large patient cohort.

Indocyanine green: An old drug with novel applications

Indocyanine green (ICG), a US Food and Drug Administration-approved fluorescent compound, has been on the medical stage for more than 60 years. Current uses include hepatic function evaluation before surgical procedure and fundus evaluation. The large safety margin and near-infrared fluorescent optical advantage of the drug have proved useful in several clinical trials of intraoperative systems for tumor removal. Several nanoparticle-sized formulations for thermal ablation and photodynamic therapy have also been evaluated in animal experiments. Studies have attempted to manipulate ICG as a reporter fluorophore with initial success. In this article, we reviewed ICG's histological applications, chemical and physical properties, current clinical applications, ongoing clinical trials, and biomedical studies and prospects. We believe that ICG could be used with novel biotechnological techniques, such as fluorescent endoscopy and photoacoustic equipment, in a range of biomedical fields.

Laparoscopic anatomical liver resection for malignancies using positive or negative staining technique with intraoperative indocyanine green-fluorescence imaging

BACKGROUND

Indications for a minimally invasive resections are increasing worldwide, but respecting anatomical planes during intraparenchymal transection is demanding. Intraoperative ICG fluorescence staining of liver parenchyma has been introduced as a tool for real-time intraoperative guidance. The aim of this study is to make a systematic review of the current relevant literature on indications, techniques, and results of laparoscopic anatomical liver resection (LALR) using intraoperative indocyanine green (ICG) fluorescence for positive and negative staining of liver segments in patients affected by liver malignancies.

METHODS

Electronic bibliographical databases (MEDLINE and PubMed) were searched according to the PRISMA criteria. English language articles meeting the selection criteria and published until June 2020 were retrieved and reviewed.

RESULTS

a total of 86 articles were initially found and 11 articles were finally included in the analysis with a total of 83 patients treated. Sixty-two patients (74.6%) underwent mono-segmentectomies. Thirty-five patients (42.1%) underwent the positive staining technique, and forty-eight patients (57.8%) the negative staining technique.

CONCLUSIONS

The positive or negative indocyanine green staining technique with real-time fluorescence guidance is an emerging and promising approach. However, the technique has to be standardized and advantages in terms of oncologic results still need validation in further studies.

Real-Time Intraoperative Ureteral Identification in Minimally Invasive Colorectal Surgery: A Systematic Review

Background: Although colorectal surgery (CRS) has currently almost entirely standardized surgical procedures, it can still show pitfalls such as the intraoperative ureteral injury. Intraoperative ureteral identification (IUI) could reduce the ureteral injuries rate but evidence is still lacking. We aimed to analyze the utility and the effectiveness of real-time IUI in minimally invasive CRS. Materials and Methods: A systematic review was performed examining available data on randomized and nonrandomized studies evaluating the utility of intraureteral fluorescence dye (IFD) and lighted ureteral stent (LUS) for intraoperative identification of ureters in CRS, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards. Primary endpoint was ureteral injuries rate. Secondary endpoints included acute kidney injury, hematuria, urinary tract infections (UTI), and fluorescence assessment. Results: After literature search, 158 studies have been recorded, 36 studies underwent full-text reviews and 12 studies met inclusion criteria. Overall, out of a total of 822 patients who successfully received IUI, 3 (0.33%) patients experienced ureteral injury. Hematuria was reported in 689 (97.6%) of patients following LUS-guided surgery and in 1 (2%) patient following IFD-guided surgery, although transient in all cases. UTI was reported in 15 (3.3%) LUS-guided resections and in 1 (2%) IFD-guided resections. Acute kidney injury occurred in 23 (2.5%) LUS-guided surgery and 1 (1%) IFD-guided surgery. Conclusions: Real-time ureteral identification techniques could represent a valid solution in complex minimally invasive CRS, safely, with no time consuming and always reproducible by surgeons. Prospective studies will be needed to confirm these findings.

The Role of Indocyanine Green Fluorescence Angiography in Complex Abdominal Wall Reconstruction: A Scoping Review of the Literature

BACKGROUND

Indocyanine green fluorescence angiography (ICGFA) is a technique for assessing vascularity and perfusion which has multiple proven applications across a variety of surgical procedures. Studies have been performed assessing its potential role in evaluating skin flap viability in complex abdominal wall reconstruction (CAWR) in order to avoid postoperative surgical site occurrences (SSO).

OBJECTIVES

This scoping review was intended to summarise the literature concerning ICGFA in CAWR in order to facilitate future evidence-based guidelines for its use.

ELIGIBILITY CRITERIA

Inclusion - cohort studies, randomised controlled trials, case series, case reports and ventral midline hernias only. Exclusion - patients aged under 18 years and non-human test subjects.

SOURCES OF EVIDENCE

PubMed, MEDLINE®, Cochrane, Embase and OpenGrey RESULTS: A total of 3416 unique titles were yielded from our search of which 9 met our inclusion criteria: 3 case reports, 1 retrospective case series, 1 prospective case series, 3 non-blinded, non-randomised retrospective case-controlled studies and 1 prospective, double-blinded randomised controlled study. The included studies varied considerably in size and method however the consensus appeared to support ICGFA as being a safe and feasible means of assessing tissue flap vascularity in CAWR. The studies returned contrasting results regarding the impact of ICGFA in predicting and avoiding SSOs however there were insufficient numbers of studies for a meta-analysis.

CONCLUSIONS

We identify three case reports and four lower quality studies suggesting a possible application for ICGFA in CAWR and two higher quality studies showing no overall benefit. Evidence-based guidelines on the role of ICGFA in CAWR will require the assessment of further studies.

Fluorescent cholangiography: An up-to-date overview twelve years after the first clinical application

Laparoscopic cholecystectomy (LC) is one of the most frequently performed gastrointestinal surgeries worldwide. Bile duct injury (BDI) represents the most serious complication of LC, with an incidence of 0.3%-0.7%, resulting in significant perioperative morbidity and mortality, impaired quality of life, and high rates of subsequent medico-legal litigation. In most cases, the primary cause of BDI is the misinterpretation of biliary anatomy, leading to unexpected biliary lesions. Near-infrared fluorescent cholangiography is widely spreading in clinical practice to delineate biliary anatomy during LC in elective and emergency settings. The primary aim of this article was to perform an up-to-date overview of the evolution of this method 12 years after the first clinical application in 2009 and to highlight all advantages and current limitations according to the available scientific evidence.

Fluorescence Image-Guided Surgery for Thyroid Cancer: Utility for Preventing Hypoparathyroidism

Background: Hypoparathyroidism is one of the most frequent complications of thyroid surgery, especially when associated with lymph node dissection in cases of thyroid cancer. Fluorescence-guided surgery is an emerging tool that appears to help reduce the rate of this complication. The present review aims to highlight the utility of fluorescence imaging in preserving parathyroid glands during thyroid cancer surgery. Methods: We performed a systematic review of the literature according to PRISMA guidelines to identify published studies on fluorescence-guided thyroid surgery with a particular focus on thyroid cancer. Articles were selected and analyzed per indication and type of surgery, autofluorescence or exogenous dye usage, and outcomes. The Methodological Index for Non-Randomized Studies (MINORS) was used to assess the methodological quality of the included articles. Results: Twenty-five studies met the inclusion criteria, with three studies exclusively assessing patients with thyroid cancer. The remaining studies assessed mixed cohorts with thyroid cancer and other thyroid or parathyroid diseases. The majority of the papers support the potential benefit of fluorescence imaging in preserving parathyroid glands in thyroid surgery. Conclusions: Fluorescence-guided surgery is useful in the prevention of post-thyroidectomy hypoparathyroidism via enhanced early identification, visualization, and preservation of the parathyroid glands. These aspects are notably beneficial in cases of associated lymphadenectomy for thyroid cancer.

Laparoscopic intraarterial catheterization with selective ICG fluorescence imaging in colorectal surgery

The quality of mesorectal resection is crucial for resection in rectal cancer, which should be performed by laparoscopy for better outcome. The use of indocyanine green (ICG) fluorescence is now routinely used in some centers to evaluate bowel perfusion. Previous studies have demonstrated in animal models that selective intra-arterial ICG staining can be used to define and visualize resection margins in rectal cancer. In this animal study, we investigate if laparoscopic intra-arterial catheterization is feasible and the staining of resection margins when performing total mesorectal excision with a laparoscopic medial to lateral approach is possible. In 4 pigs, laparoscopic catheterization of the inferior mesenteric artery (IMA) is performed using a seldinger technique. After a bolus injection of 10 ml ICG with a concentration of 0.25 mg/ml, a continuous intra-arterial perfusion was established at a rate of 2 ml/min. The quality of the staining was evaluated qualitatively. Laparoscopic catheterization was possible in all cases, and the average time for this was 30.25 ± 3.54 min. We observed a significant fluorescent signal in all areas of the IMA supplied, but not in other parts of the abdominal cavity or organs. In addition, the mesorectum showed a sharp border between stained and unstained tissue. Intraoperative isolated fluorescence augmentation of the rectum, including the mesorectum by laparoscopic catheterization, is feasible. Inferior mesenteric artery catheterization and ICG perfusion can provide a fluorescence-guided roadmap to identify the correct plane in total mesorectal excision, which should be investigated in further studies.

Indocyanine green staining for intraoperative perfusion assessment

Indocyanine green (ICG) is a fluorescent iodide-based dye which is used in hepatic surgery to evaluate the biliary tree, liver perfusion, and function. While liver perfusion assessment and delineation of anatomic regions has been performed using ultrasound, ischemic demarcation, or indigo carmine/methylene blue staining, ICG staining can overcome limitations associated with these techniques, such as rapid washout, lack of precision, non-demarcation in damaged livers, and lack of intraparenchymal fidelity. ICG can be used to fluoresce target segments/tumors (Positive staining) or counterstain normal liver tissue leaving areas of interest unstained (negative staining). Moreover, ICG enhancement patterns vary for different tumors, such as colorectal liver metastases vs. hepatocellular carcinoma, providing not only help with detection but also assessment of differentiation. In the field of oncology, benefits of ICG include detection of small radiographically occult tumors, distinction between cirrhotic nodules and cancer, identification of necrotic tumors in chemotherapy-damaged livers, and determining margins when intraoperative ultrasound is inadequate. While ICG has important and expanding indications in hepatic surgery, limitations include small depth of penetrance, need for special monitors/equipment, and potential for dye spillage. ICG is well tolerated, has a small learning curve, minimally invasive surgical integration, and options of both portal vein and peripheral vein injection and hence is a safe and versatile method of anatomic liver mapping, tumor visualization, and liver graft perfusion evaluation in oncologic surgery and liver transplantation. Advancements in technique and technology associated with ICG will aid in increasing the indications in hepato-biliary surgery.

ICG fluorescence imaging in colorectal surgery: a snapshot from the ICRAL study group

Background

Fluorescence-guided visualization is a recently proposed technology in colorectal surgery. Possible uses include evaluating perfusion, navigating lymph nodes and searching for hepatic metastases and peritoneal spread. Despite the absence of high-level evidence, this technique has gained considerable popularity among colorectal surgeons due to its significant reliability, safety, ease of use and relatively low cost. However, the actual use of this technique in daily clinical practice has not been reported to date.

Methods

This survey was conducted on April 2020 among 44 centers dealing with colorectal diseases and participating in the Italian ColoRectal Anastomotic Leakage (iCral) study group. Surgeons were approximately equally divided based on geographical criteria from multiple Italian regions, with a large proportion based in public (89.1%) and nonacademic (75.7%) centers. They were invited to answer an online survey to snapshot their current behaviors regarding the use of fluorescence-guided visualization in colorectal surgery. Questions regarding technological availability, indications and techniques, personal approaches and feelings were collected in a 23-item questionnaire.

Results

Questionnaire replies were received from 37 institutions and partially answered by 8, as this latter group of centers do not implement fluorescence technology (21.6%). Out of the remaining 29 centers (78,4%), fluorescence is utilized in all laparoscopic colorectal resections by 72.4% of surgeons and only for selected cases by the remaining 27.6%, while 62.1% of respondents do not use fluorescence in open surgery (unless the perfusion is macroscopically uncertain with the naked eye, in which case 41.4% of them do). The survey also suggests that there is no agreement on dilution, dosing and timing, as many different practices are adopted based on personal judgment. Only approximately half of the surgeons reported a reduced leak rate with fluorescence perfusion assessment, but 65.5% of them strongly believe that this technique will become a minimum requirement for colorectal surgery in the future.

Conclusion

The survey confirms that fluorescence is becoming a widely used technique in colorectal surgery. However, both the indications and methods still vary considerably; furthermore, the surgeons' perceptions of the results are insufficient to consider this technology essential. This survey emphasizes the need for further research to reach recommendations based on solid scientific evidence.

Super-Selective Intra-Arterial Indocyanine Green Administration for Near-Infrared Fluorescence-Based Positive Staining of Hepatic Segmentation: A Feasibility Study

BACKGROUND

Despite the increasing number of laparoscopic hepatic procedures for the resection of hepatocellular carcinoma (HCC), intraoperative tumor localization and demarcation remains challenging in comparison to open surgery. In this study, we evaluated the feasibility of positive liver segment staining through the super-selective intra-arterial indocyanine green (ICG) administration.

METHODS

Eight patients presenting with a single HCC underwent an interventional vascular procedure followed by laparoscopic surgery. A microcatheter was advanced into the hepatic artery branches perfusing the HCC followed by digital subtraction angiography and angiography computed tomography (angio-CT). Patients were then transferred to the operating room, and a laparoscopic hepatectomy was performed under ultrasound guidance. A 5 mL bolus of ICG with a concentration of .125 mg/mL was injected through the microcatheter, and a near-infrared laparoscope was used to detect the fluorescence signal to assess the correspondence between the fluorescence-based demarcation and the intraoperative ultrasound-based demarcation.

RESULTS

The duration for the angiography procedure was 32.7 +/- 5.3 min, and it took 242 +/- 118 min from the end of angiography procedure until the start of the surgical procedure. In all cases, the fluorescent liver segment was corresponding to the angio-CT findings. In 6/8 cases, fluorescence imaging was considered helpful in the identification of the resection line. In 3 patients, the resection line was changed according to the positively stained liver segment.

CONCLUSION

We successfully demonstrated the feasibility of the super-selective intra-arterial ICG administration for fluorescence-based positive staining of hepatic segmentation during laparoscopic surgery for HCC (NCT04266548).

Functional anatomical hepatectomy guided by indocyanine green fluorescence imaging in patients with localized cholestasis: Report of four cases

BACKGROUND

Liver cancer is a malignant tumor with a high incidence. At present, the most effective treatment is laparoscopic hepatectomy (LH). Indocyanine green fluorescence imaging (ICG-FI) has become an important tool in LH, and the most common fluorescent types of tumors are total fluorescence, partial fluorescence, and rim fluorescence.

CASE SUMMARY

We presented four cases of LH guided by ICG-FI in which we also observed the fourth special fluorescent type. When the tumor or intrahepatic stone compresses the adjacent bile duct to cause local cholestasis, the liver segment or subsegment with obstructed bile drainage will show strong fluorescence. Complete removal of the lesion together with the fluorescent liver parenchyma may help reduce the risk of tumor or stone recurrence.

CONCLUSION

This type of partial fluorescence can indicate local biliary compression, and the resection method is related to bile drainage, which may be called functional anatomical hepatectomy and ensures radical resection of the lesion.

Fluorescence guided surgery for pituitary adenomas

PURPOSE

Resection of pituitary adenomas presents a number of unique challenges in neuro-oncology. The proximity of these lesions to key vascular and endocrine structures as well as the need to interpret neuronavigation in the context of shifting tumor position increases the complexity of the operation. More recently, substantial advances in fluorescence-guided surgery have been demonstrated to facilitate the identification of numerous tumor types and result in increased rates of complete resection and overall survival.

METHODS

A review of the literature was performed, and data regarding the mechanism of the fluorescence agents, their administration, and intraoperative tumor visualization were extracted. Both in vitro and in vivo studies were assessed. The application of these agents to pituitary tumors, their advantages and limitations, as well as future directions are presented here.

RESULTS

Numerous laboratory and clinical studies have described the use of 5-ALA, fluorescein, indocyanine green, and OTL38 in pituitary lesions. All of these drugs have been demonstrated to accumulate in tumor cells. Several studies have reported the successful use of the majority of the agents in inducing intraoperative tumor fluorescence. However, their sensitivity and specificity varies across the literature and between functioning and non-functioning adenomas.

CONCLUSIONS

At present, numerous studies have shown the feasibility and safety of these agents for pituitary adenomas. However, further research is needed to assess the applicability of fluorescence-guided surgery across different tumor subtypes as well as explore the relationship between their use and postoperative clinical outcomes.

The clinical value of indocyanine green fluorescence navigation system for laparoscopic partial nephrectomy in the case of complex renal clear cell carcinoma (R.E.N.A.L score ≥7)

Objective: We demonstrated the potential clinical utility of the indocyanine green (ICG) fluorescence navigation system for laparoscopic partial nephrectomy in the case of complex renal clear cell carcinoma (R.E.N.A.L score ≥7).

Methods: Compared with the general laparoscopic partial nephrectomy and ICG fluorescence laparoscopic partial nephrectomy, a series of indicators were analyzed: the basic information like age, sex, and the tumor location; the operative information like the time of renal ischemia, the blood loss, and the complications; and other important indexes like the renal function, the volume of the tumor, and the weight of the specimens.

Results: 60 patients were included in this study. 21 patients in the group of fluorescence laparoscopy, and 39 patients in the group of general laparoscopy. There was no statistical difference for most indexes except the renal function. Preoperative serum creatinine was close (82.4±11.7 vs. 77.5±12.7, mmol/l, p=0.15). However, the patients in the group of fluorescence laparoscopy got a smaller serum creatinine growth degree (12.9±5.3 vs. 17.9±7.3, mmol/l, p=0.008), and a less decreasing level of GFR (16.5±6.4 vs. 24.4±9.8, mL/(min*1.73m²), p=0.001) after the operation. In addition, the average volume of the tumor (28.8±9.8 vs. 26.9±8.2, cm³, p=0.43) and the weight of the specimens (32.3±10.4 vs. 33.9±8.9, g, p=0.52) were no statistical difference. But the group of fluorescence laparoscopy had a smaller ratio of the weight/ the volume (1.13±0.06 vs. 1.28±0.10, g/cm³, p<0.001). And the two groups had a similar test-positivity rate of surgical margins (p=0.19).

Conclusion: Without increasing the rate of positive surgical margins, ICG fluorescence navigation system for laparoscopic partial nephrectomy for complex renal clear cell carcinoma could conserve more normal renal tissue.

Inter-user variation in the interpretation of near infrared perfusion imaging using indocyanine green in colorectal surgery

INTRODUCTION

Despite increasing endorsement of near-infrared perfusion assessment using indocyanine green (ICG) during colorectal surgery, little work has yet been done regarding learning curve and interobserver variation most especially on surgical video reflective of real-world usage.

METHODS

Surgeons with established expertise in ICG usage were invited to participate in the study along with others without such experience including trainees. All participants completed an opinion questionnaire and interpreted video presentations of fluorescence angiograms in a variety of colorectal case scenarios. An interactive video platform (Mindstamp) enabled dynamic annotation. Statistical analysis of data was performed using Kruskal-Wallis and Mann-Whitney testing as well as Intraclass Correlation Coefficients and Fleiss Multi-rater Kappa Scoring.

RESULTS

Forty participants (six experts) completed questionnaire data and provided judgement of 14 videos (nine showing proximal colonic transection site perfusion, four showing completed anastomoses and one an acutely strangulated bowel). 70% felt > 10 cases were needed for competency in use with the majority of experts advocating > 50 (p < 0.05). Overall agreement among experts was "good" for videos showing colonic transection perfusion (versus "moderate" among in-experts) with experts clustering more distally. In contrast, there was no interpretation concordance among experts or in-experts when judging ICG perfusion sufficiency on a yes/no basis.

CONCLUSION

Significant experience is recommended before reliance on ICG perfusion angiograms. ICG fluorescence assessment is prone to variable interpretation and influenced by experience and, perhaps, knowledge of preassessment operative steps suggesting a role for objective flow analysis with artificial intelligence methods as the next phase of this technology.

Indocyanine green fluorescence imaging via endoscopic nasal biliary drainage during laparoscopic deroofing of liver cysts

Laparoscopic deroofing of liver cysts is widely accepted as the treatment of symptomatic huge liver cysts. As bile leakage is a common complication of this procedure, indocyanine green (ICG) imaging has played an active role in detecting intrahepatic biliary tract. However, infusion ICG imaging needs time rag after injection due to moving from bloodstream to bile, and also, additional injection is needed when the fluorescent imaging is not clear. To cover this weakness of ICG imaging, we first applied ICG imaging via 5-Fr endoscopic nasal biliary drainage (ENBD) during laparoscopic deroofing of liver cysts. This technique promptly gives us ICG imaging after ICG injection from ENBD; in addition, direct ICG imaging sometimes reveals minor leakage from sealing line and staple lines; therefore, we believe that direct ICG imaging via ENBD helps us to prevent post-operative bile leakage.

Protein-Enhanced NIR-IIb Emission of Indocyanine Green for Functional Bioimaging

Fluorescence imaging performed in the 1500-1700 nm spectral range (labeled near-infrared IIb, NIR-IIb) promises high imaging contrast and spatial resolution for its little photon scattering effect and minimum autofluorescence. Though inorganic and organic probes have been developed for NIR-IIb bioimaging, most are in the preclinical stage, hampering further clinical application. Herein, we showed that indocyanine green (ICG), a US Food and Drug Administration (FDA)-approved agent, exhibited a remarkable amount of NIR-IIb emission when dissolved into different protein solutions, including human serum albumin, rat bile, and fetal bovine serum. We performed fluorescence imaging in the NIR-IIb window to visualize structures of the lymph system, extrahepatic biliary tract, and cerebrovascular. The results demonstrated that proteins promoted NIR-IIb emission of ICG in vivo and that NIR-IIb imaging with ICG preserved a higher signal-to-background ratio and spatial resolution compared with the conventional NIR-II fluorescence imaging. Our findings confirm that NIR-IIb fluorescence imaging can be successfully performed using the clinically approved agent ICG. Further clinical application in the NIR-IIb region would hopefully be carried out with appropriate ICG-protein solutions.

Successful Localization and Resection of Small Pancreatic Cystic Insulinoma Using Intraoperative Near-Infrared Fluorescence Imaging: A Case Report and Literature Review

Pancreatic cystic insulinoma is an uncommon tumor. Perioperative localization remained challenging if the tumor is atypical with cystic feature or in small size. Near-infrared (NIR) imaging is a technique by injecting fluorescent dye intravenously, which accumulates to the target lesion and creating signal by laser sources. The signal helps surgeons to identify the lesion during operation, but little experience has been reported regarding the use of imaging NIR technique for localizing cystic insulinoma. We present a 29-year-old female patient with a symptomatic pancreatic cystic insulinoma (1.2 cm) as assessed by clinical symptom, laboratory evidence, and magnetic resonance cholangiopancreatography. With an aid of NIR imaging technique, this cystic tumor was localized easily at operation. Also, the fluorescence imaging visualized the tumor part, guided us to identify the safe margin, and preserved the normal pancreatic structure. Pathologic report confirmed that the tumor was a well-differentiated cystic insulinoma. This case demonstrates that pancreatic cystic insulinoma in small size can be intraoperatively localized by NIR imaging, a relatively safe and easy technique.

Fluorescence guided intraluminal endoscopy in the gastrointestinal tract: A systematic review

BACKGROUND

Conventional endoscopy is based on full spectrum white light. However, different studies have investigated the use of fluorescence based endoscopy systems where the white light has been supplemented by infrared light and the use of relevant fluorophores. Fluorescence endoscopy utilizes the fluorescence emitted from a fluorophore, visualizing what is not visible to the naked eye.

AIM

To explore the feasibility of fluorescence endoscopy and evaluate its use in diagnosing and evaluating gastrointestinal disease.

METHODS

We followed the PRISMA guidelines for this systematic review. The research covered five databases; PubMed, Scopus, Web of Science, Embase, and the Cochrane Collection, including only studies in English and Scandinavian languages. Authors screened title and abstract for inclusion, subsequently full-text for inclusion according to eligibility criteria listed in the protocol. The risk of bias was assessed for all studies according to the Newcastle-Ottawa Scale. The authors extracted the data and reported the results in both text and tables.

RESULTS

We included seven studies in the systematic review after screening a total of 2769 papers. The most prominent fluorophore was indocyanine green (n = 6), and whereas one study (n = 1) used Bevacizumab 800-CW. Three studies investigated fluorescence endoscopy in detecting varices, adenomas in patients with familial adenomatous polyposis and neoplasms in the gastrointestinal tract. Four studies evaluated the usefulness of fluorescence endoscopy in assessing tumor invasion. Three of the four studies reported an exceptional diagnostic accuracy (93%, 89% and 88%) in assessing tumor invasion, thus representing better visualization and more correct diagnosis by fluorescence endoscopy compared with the conventional endoscopy. The relationship between the endoscopic findings, tumor invasion, and tumor vascularity was evaluated in two studies showing a significant correlation (^dP < 0.05 and ^bP < 0.01).

CONCLUSION

The use of fluorescence endoscopy is a promising method adding diagnostic value in the detection of neoplasia, adenomas, and assessment of tumor invasion within the gastrointestinal tract. More studies are needed to utilize the feasibility of fluorescence endoscopy compared with other endoscopic methods.