Extrahepatic biliary tract visualization using near-infrared fluorescence imaging with indocyanine green: optimization of dose and dosing time

Surgical strategies for challenging common bile duct stones in the endoscopic era: A comprehensive review of current evidence

While endoscopic retrograde cholangiopancreatography (ERCP) remains the primary treatment modality for common bile duct stones (CBDS) or choledocholithiasis due to advancements in instruments, surgical intervention, known as common bile duct exploration (CBDE), is still necessary in cases of difficult CBDS, failed endoscopic treatment, or altered anatomy. Recent evidence also supports CBDE in patients requesting single-step cholecystectomy and bile duct stone removal with comparable outcomes. This review elucidates relevant clinical anatomy, selection indications, and outcomes to enhance surgical understanding. The selection between trans-cystic (TC) vs trans-choledochal (TD) approaches is described, along with stone removal techniques and ductal closure. Detailed surgical techniques and strategies for both the TC and TD approaches, including instrument selection, is also provided. Additionally, this review comprehensively addresses operation-specific complications such as bile leakage, stricture, and entrapment, and focuses on preventive measures and treatment strategies. This review aims to optimize the management of CBDS through laparoscopic CBDE, with the goal of improving patient outcomes and minimizing risks.

Determining the patency of biliary tracts in dogs with gallbladder mucocele using near-infrared cholangiography with indocyanine green

Cholecystectomy is indicated for gallbladder mucoceles (GBM). Evaluating the patency of the biliary duct and precise biliary tree visualization is crucial for reducing the risk of compromised bile flow after surgery. Therefore, intraoperative cholangiography (IOC) is recommended during cholecystectomy to prevent biliary tract injury. Although indocyanine green (ICG) cholangiography has been extensively reported in human medicine, only one study has been conducted in veterinary medicine. Therefore, this study aimed to demonstrate the use of ICG for IOC to identify fluorescent biliary tract images and determine the patency of the common bile duct during cholecystectomy in dogs. This study comprised 27 dogs, consisting of 17 with gallbladder mucoceles (GBM) and 10 controls, specifically including dogs that had undergone elective cholecystectomy for GBM. ICG injection (0.25 mg/kg) was administered intravenously at least 45 minutes before surgery. During the operation, fluorescent images from cholangiography were displayed on the monitor and obtained in black-and-white mode for the comparison of fluorescence intensity (FI). The FI values of the gallbladders (GBs) and common bile duct (CBD) were measured using FI analyzing software (MGViewer V1.1.1, MetapleBio Inc.). The results demonstrated successful CBD patency identification in all cases. Mobile GBM showed partial gallbladder visibility, whereas immobile GBM showed limited visibility. Additionally, insights into the adequate visualization of the remaining extrahepatic biliary tree anatomy were provided, extending beyond the assessment of CBD patency and gallbladder intensity. Our study demonstrates the potential of fluorescent IOC using intravenous injection of ICG for assessing the patency of the cystic duct and common bile duct during cholecystectomy in patients with GBM, eliminating the need for surgical catheterization and flushing of the biliary ducts. Further research is warranted to investigate and validate the broader applicability of ICG cholangiography in veterinary medicine.

Near-infrared fluorescence cholangiography in dogs: A pilot study

OBJECTIVE

To determine the effect of indocyanine green (ICG) dose and timing of administration on near-infrared fluorescence (NIRF) imaging of the normal canine biliary tree.

STUDY DESIGN

Preclinical prospective study.

ANIMALS

Eight purpose-bred beagles.

METHODS

The dogs were randomized to receive two of four intravenous ICG dose (low [L]:0.05 mg/kg or high [H]:0.25 mg/kg)/time (0 and 3 h prior to NIRF) combinations. NIRF images were collected every 10 min for 120 min. Target (cystic duct)-to-background (liver) ratios were calculated for all timepoints and compared.

RESULTS

ICG cholangiography was successful in all dogs. The contrast ratio was above 1 in the L0 group by 20 min and reached its peak at 100 min. In the H0 group, the ratio was above 1 by 60 min and reached its peak at 90 min. Contrast ratios above 2 (fluorescence twice as bright in the cystic duct compared to the liver) were maintained from 180 to 300 min for L3 and H3 and was achieved after 80 min for L0.

CONCLUSION

Low dose ICG provided better ratios early after injection compared to the high dose which remained highly concentrated in the liver tissue after injection. Both doses provided excellent visualization of the biliary tree at 3 h post injection, low dose ICG provided better ratios from 3 to 5 h post injection. Based on these results, 0.05 mg/kg of ICG administered at anesthetic premedication, or as early as 3 h prior to laparoscopic surgery should yield optimal fluorescence images.

CLINICAL SIGNIFICANCE

This study provides guidelines for NIRF cholangiography in clinically normal dogs.

Near-infrared cholangiography with intragallbladder indocyanine green injection in minimally invasive cholecystectomy

Laparoscopic cholecystectomy (LC) remains one of the most commonly performed procedures in adult and paediatric populations. Despite the advances made in intraoperative biliary anatomy recognition, iatrogenic bile duct injuries during LC represent a fatal complication and consist an economic burden for healthcare systems. A series of methods have been proposed to prevent bile duct injury, among them the use of indocyanine green (ICG) fluorescence. The most commonly reported method of ICG injection is the intravenous administration, while literature is lacking studies investigating the direct intragallbladder ICG injection. This narrative mini-review aims to assess the potential applications, usefulness, and limitations of intragallbladder ICG fluorescence in LC. Authors screened the available international literature to identify the reports of intragallbladder ICG fluorescence imaging in minimally invasive cholecystectomy, as well as special issues regarding its use. Literature search retrieved four prospective cohort studies, three case-control studies, and one case report. In the three case-control studies selected, intragallbladder near-infrared cholangiography (NIRC) was compared with standard LC under white light, with intravenous administration of ICG for NIRC and with standard intraoperative cholangiography (IOC). In total, 133 patients reported in the literature have been administered intragallbladder ICG administration for biliary mapping during LC. Literature includes several reports of intragallbladder ICG administration, but a standardized technique has not been established yet. Published data suggest that NIRC with intragallbladder ICG injection is a promising method to achieve biliary mapping, overwhelming limitations of IOC including intervention and radiation exposure, as well as the high hepatic parenchyma signal and time interval needed in intravenous ICG fluorescence. Evidence-based guidelines on the role of intragallbladder ICG fluorescence in LC require the assessment of further studies and multicenter data collection into large registries.

Semi-automatic standardized analysis method to objectively evaluate near-infrared fluorescent dyes in image-guided surgery

Significance

Near-infrared fluorescence imaging still lacks a standardized, objective method to evaluate fluorescent dye efficacy in oncological surgical applications. This results in difficulties in translation between preclinical to clinical studies with fluorescent dyes and in the reproduction of results between studies, which in turn hampers further clinical translation of novel fluorescent dyes.

Aim

Our aim is to develop and evaluate a semi-automatic standardized method to objectively assess fluorescent signals in resected tissue.

Approach

A standardized imaging procedure was designed and quantitative analysis methods were developed to evaluate non-targeted and tumor-targeted fluorescent dyes. The developed analysis methods included manual selection of region of interest (ROI) on white light images, automated fluorescence signal ROI selection, and automatic quantitative image analysis. The proposed analysis method was then compared with a conventional analysis method, where fluorescence signal ROIs were manually selected on fluorescence images. Dice similarity coefficients and intraclass correlation coefficients were calculated to determine the inter- and intraobserver variabilities of the ROI selections and the determined signal- and tumor-to-background ratios.

Results

The proposed non-targeted fluorescent dyes analysis method showed statistically significantly improved variabilities after application on indocyanine green specimens. For specimens with the targeted dye SGM-101, the variability of the background ROI selection was statistically significantly improved by implementing the proposed method.

Conclusion

Semi-automatic methods for standardized quantitative analysis of fluorescence images were successfully developed and showed promising results to further improve the reproducibility and standardization of clinical studies evaluating fluorescent dyes.

Real-time fluorescence-guided adhesiolysis with indocyanine green in intra-abdominal surgery (with video)

Intra-abdominal adhesions have consistently posed a challenge for surgeons during procedures. This study aims to investigate the feasibility of utilizing indocyanine green (ICG) in conjunction with near-infrared imaging for the detection of intra-abdominal adhesions. In vitro, we analyzed factors affecting ICG fluorescence. We divided SD rats into groups to study ICG excretion in different digestive tract regions. Additionally, we reviewed surgical videos from previous cholecystectomy cases, categorizing them by ICG injection timing and assessing fluorescence imaging in various digestive tract regions. Finally, we preoperatively injected ICG into two cholecystectomized patients with abdominal adhesions, guiding intraoperative adhesiolysis with near-infrared fluorescence imaging. In vitro, we observed a significant influence of protein and ICG concentrations on ICG fluorescence intensity. Our rat experiments unveiled a strong and highly significant correlation (Kendall's tau-b = 1, P < 0.001) between the timing of ICG injection and the farthest point of intestinal fluorescence. A retrospective case analysis further validated this finding (Kendall's tau-b = 0.967, P < 0.001). Under the guidance of fluorescence navigation, two cholecystectomized patients with intra-abdominal adhesions successfully underwent adhesiolysis, and no postoperative complications occurred. The intraoperative combination of ICG with near-infrared fluorescence imaging effectively enhances the visibility of the liver, bile ducts, and various segments of the gastrointestinal tract while providing real-time navigation. This real-time fluorescence guidance has the potential to aid surgeons in the dissection of intra-abdominal adhesions.

Fluorescence cholangiography for laparoscopic cholecystectomy: how, when, and why? A single-center preliminary study

INTRODUCTION

Bile duct injuries avoidance is a key goal of biliary surgery. In this prospective study we evaluate the safety and feasibility of ICG fluorescent cholangiography during laparoscopic cholecystectomy (LC) focusing on the optimization of timing and dose administration.

MATERIAL AND METHODS

From February to December 2022 fifty-four LC were performed with fluorescence imaging in our surgical department. 2.5 mg ICG were administered intravenously between 5 h and 24 h before surgery. Near-infrared fluorescent cholangiography (NIRF-C) was performed. Adequate fluorescence was evaluated by comparing agent accumulation in the gallbladder and the extrahepatic duct and the background of liver parenchyma.

RESULTS

Biliary anatomy was identified in all cases. Median time of ICG administration was 11 h previous surgery and three groups of patients were identified: group A receiving ICG 5-9 h, group B 10-14 h, group C 15-24 h before surgery. Peak contrast was gained in group B, with minimal fluorescence of liver parenchyma and more intense visibility of the biliary tract. Intraoperative cholangiogram was unnecessary in all cases.

CONCLUSION

Fluorescent cholangiography during LC is safe and feasible overcoming the limits of other techniques available. 2.5 mg ICG administered 10-14 h before surgery produces optimal outcomes for near-infrared (NIR) fluorescent cholangiography.

Investigation of the optimal indocyanine green dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy with an ultra-high-definition 4K fluorescent system: a randomized controlled trial

This study aimed to investigate the indocyanine green (ICG) dose in real-time fluorescent cholangiography during laparoscopic cholecystectomy (LC) with a 4K fluorescent system. A randomized controlled clinical trial was conducted in patients who underwent LC for treatment of cholelithiasis. Using the OptoMedic 4K fluorescent endoscopic system, we compared four different doses of ICG (1, 10, 25, and 100 µg) administered intravenously within 30 min preoperatively and evaluated the fluorescence intensity (FI) of the common bile duct and liver background and the bile-to-liver ratio (BLR) of the FI at three timepoints: before surgical dissection of the cystohepatic triangle, before clipping the cystic duct, and before closure. Forty patients were randomized into four groups, and 33 patients were fully analyzed, with 10 patients in Group A (1 µg), 7 patients in Group B (10 µg), 9 patients in Group C (25 µg), and 7 patients in Group D (100 µg). The preoperative baseline characteristics were compared among groups (p > 0.05). Group A showed no or minimal FI in the bile duct and liver background, while Group D showed extremely high FIs in the bile duct and in the liver background at the three timepoints. Groups B and C presented with visible FI in the bile duct and low FI in the liver background. With increasing ICG doses, the FIs in the liver background and bile duct gradually increased at the three timepoints. The BLR, however, showed no increasing trend with an increasing ICG dose. A relatively high BLR on average was found in Group B, without a significant difference compared to the other groups (p > 0.05). An ICG dose ranging from 10 to 25 µg by intravenous administration within 30 min preoperatively was appropriate for real-time fluorescent cholangiography in LC with a 4K fluorescent system. Registration: This study was registered in the Chinese Clinical Trial Registry (ChiCTR No: ChiCTR2200064726).

[Indocyanine Green (ICG) in Robotic Liver Surgery]

Indocyaningrün (IGC) ist ein Fluoreszenzfarbstoff, der durch Hepatozyten aufgenommen und biliär ausgeschieden wird. Dadurch kann er zur Leberfunktionsdiagnostik eingesetzt werden. Neben dieser Eigenschaft kumuliert ICG in und um primäre und sekundäre Lebertumoren, die dadurch intraoperativ durch Stimulation mit Licht von 840 nm fluoreszierend dargestellt werden können. Durch die biliäre Ausscheidung werden die extrahepatischen Gallengänge mittels ICG visualisiert. Mithilfe von direkter oder indirekter Fluoreszenzangiografie können intraoperativ individuelle Lebersegmente oder Lebersegmentkombinationen identifiziert werden. Da besonders bei minimalinvasiven Operationen die Haptik fehlt, kann ICG durch die genannten Eigenschaften dazu beitragen, in Kombination mit dem intraoperativen Ultraschall die onkologische Präzision bei der Operation von Lebertumoren zu optimieren. Bei Eingriffen an den Gallengängen können durch deren Darstellung mittels ICG unnötige Komplikationen vermieden werden. Die Identifikation von Lebersegmenten verbessert die chirurgische Präzision, was postoperative Komplikationen reduzieren kann. Aufgrund seiner vielseitigen, einfachen und nebenwirkungsarmen Anwendungsmöglichkeiten bietet ICG gute Voraussetzungen für den Einsatz bei robotischen hepatobiliären Operationen. Im folgenden Video werden Beispiele zur intraoperativen Nutzung von ICG im Rahmen robotischer Eingriffe demonstriert.

Identification of the ideal weight-based indocyanine green dose for fluorescent cholangiography

BACKGROUND

Ideal visualization of fluorescent cholangiography during laparoscopic cholecystectomy is when maximum fluorescence into biliary ducts and absent signal into liver parenchyma, defined as "signal to background ratio" (SBR), is obtained. Such condition is mainly dependent by indocyanine green (ICG) dose and timing. The aim of this study was to identify the ideal ICG dose to obtain the best possible intraoperative visualization of the extra-hepatic biliary tree.

METHODS

The first part of the study was used to define a range of small weight-based ICG dosages using the mathematical function bisection method. During the second part of the study, the midpoint dose of the identified range, was tested in 50 consecutive cholecystectomies using a laser-based fluorescence laparoscopic camera (SynergyID system by Arthrex, Naples, FL, USA). Timing administration was set at 1 h before surgery, since this is the most common situation in clinical practice. Fluorescence intensity of bile ducts and liver parenchyma were assessed both subjectively, by blinded operative surgeon, as well as objectively, using an image analysis software (Fiji plugin), before and after Calot's triangle dissection.

RESULTS

Fourteen patients were included in the first part of the study and ICG dose between 0.01191406 and 0.0119873 mg/kg was identified. The second part confirmed previous results after testing the dosage equal to 0.0119 mg/kg (midpoint of the defined range) in 50 consecutive cholecystectomies. Cystic duct was identified in 66 and 100% of cases before and after dissection of Calot's triangle respectively. On the other hand, common bile duct was identified in 82 and 92% before and after dissection respectively. Subjective and objective SBRs confirmed the benefit of the identified ICG dose.

CONCLUSION

ICG dose calculated by 0.0119 mg/kg administered one hour before surgery allows an ideal intraoperative visualization of the extra-hepatic biliary tree.

REGISTRATION NUMBER

ISRCTN10190039.

Laboratory scoring system to predict hepatic indocyanine green clearance ability during fluorescence imaging-guided laparoscopic hepatectomy

BACKGROUND

Indocyanine green (ICG) fluorescence played an important role in tumor localization and margin delineation in hepatobiliary surgery. However, the preoperative regimen of ICG administration was still controversial. Factors associated with tumor fluorescence staining effect were unclear.

AIM

To investigate the preoperative laboratory indexes corelated with ICG fluorescence staining effect and establish a novel laboratory scoring system to screen specifical patients who need ICG dose adjustment.

METHODS

To investigate the predictive indicators of ICG fluorescence characteristics in patients undergoing laparoscopic hepatectomy from January 2018 to January 2021 were included. Blood laboratory tests were completed within 1 wk before surgery. All patients received 5 mg ICG injection 24 h before surgery for preliminary tumor imaging. ImageJ software was used to measure the fluorescence intensity values of regions of interest. Correlation analysis was used to identify risk factors. A laboratory risk model was established to identify individuals at high risk for high liver background fluorescence.

RESULTS

There were 110 patients who were enrolled in this study from January 2019 to January 2021. The mean values of fluorescence intensity of liver background (FI-LB), fluorescence intensity of gallbladder, and fluorescence intensity of target area were 18.87 ± 17.06, 54.84 ± 33.29, and 68.56 ± 36.11, respectively. The receiver operating characteristic (ROC) curve showed that FI-LB was a good indicator for liver clearance ability [area under the ROC curve (AUC) = 0.984]. Correlation analysis found pre-operative aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, adenosine deaminase, and lactate dehydrogenase were positively associated with FI-LB and red blood cell, cholinesterase, and were negatively associated with FI-LB. Total laboratory risk score (TLRS) was calculated according to ROC curve (AUC = 0.848, sensitivity = 0.773, specificity = 0.885). When TLRS was greater than 6.5, the liver clearance ability of ICG was considered as poor.

CONCLUSION

Preoperative laboratory blood indicators can predict hepatic ICG clearance ability. Surgeons can adjust the dose and timing of ICG preoperatively to achieve better liver fluorescent staining.

Rigid and Photostable Shortwave Infrared Dye Absorbing/Emitting beyond 1200 nm for High-Contrast Multiplexed Imaging

The shortwave infrared (SWIR) spectral region beyond 1200 nm offers optimal tissue penetration depth and has broad potential in diagnosis, therapy, and surgery. Here, we devised a novel class of fluorochromic scaffold, i.e., a tetra-benzannulated xanthenoid (EC7). EC7 absorbs/emits maximally at 1204/1290 nm in CH₂Cl₂ and exhibits an unparalleled molar absorptivity of 3.91 × 10⁵ cm^-1 M^-1 and high transparency to light at 400-900 nm. It also exhibited high resistance toward both photobleaching and symmetry breaking due to its unique structural rigidity. It is feasible for in vivo bioimaging and particularly suitable to couple with the shorter-wavelength analogues for high-contrast multiplexing. High-contrast dual-channel intraoperative imaging of the hepatobiliary system and three-channel in vivo imaging of the intestine, the stomach, and the vasculature were showcased. EC7 is a benchmark fluorochrome for facile biomedical exploitation of the SWIR region beyond 1200 nm.

Quantification of Indocyanine Green Fluorescence Imaging in General, Visceral and Transplant Surgery

Near-infrared (NIR) imaging with indocyanine green (ICG) has proven to be useful in general, visceral, and transplant surgery. However, most studies have performed only qualitative assessments. Therefore, a systematic overview of all studies performing quantitative indocyanine green evaluation in general, visceral, and transplant surgeries should be conducted. Free term and medical subject heading (MeSH) term searches were performed in the Medline and Cochrane databases until October 2022. The main categories of ICG quantification were esophageal surgery (24.6%), reconstructive surgery (24.6%), and colorectal surgery (21.3%). Concordantly, anastomotic leak (41%) was the main endpoint, followed by the assessment of flap perfusion (23%) and the identification of structures and organs (14.8%). Most studies examined open surgery (67.6%) or laparoscopic surgery (23.1%). The analysis was mainly carried out using manufacturer software (44.3%) and open-source software (15.6%). The most frequently analyzed parameter was intensity over time for blood flow assessment, followed by intensity alone or intensity-to-background ratios for structure and organ identification. Intraoperative ICG quantification could become more important with the increasing impact of robotic surgery and machine learning algorithms for image and video analysis.

Real-time Indocyanine Green Fluorescence Technique Reduces Anastomotic Leakage in Bilioenteric Anastomosis: A Case Report and literature review

BACKGROUND

Anastomotic leakage is a serious complication that can occur in bilioenteric anastomosis surgery, leading to significant morbidity and mortality. Currently, practitioners rely on subjective measures to determine anastomotic perfusion and mechanical integrity, which have limitations. The use of indocyanine green fluorescence technology has become increasingly widespread in clinical practice, especially in gastrointestinal-related surgery. This technique has a unique role in evaluating the blood perfusion of anastomoses and reducing the incidence of anastomotic leakage. However, there have been no reports of its use in bilioenteric anastomosis surgery. Further research is needed to investigate the potential benefits of indocyanine green fluorescence technology in improving outcomes and reducing complications in this type of surgery.

CASE SUMMARY

a 50-year-old female patient underwent total laparoscopic radical resection of cholangiocarcinoma. During the surgery, indocyanine green fluorescence technology was used to complete the biliary intestinal anastomosis under full visual and dynamic monitoring. The patient recovered well after the operation without experiencing biliary leakage or other complications.

CONCLUSION

The present case study underscores the potential advantages associated with the incorporation of intraoperative real-time indocyanine green (ICG) technology in bilioenteric anastomosis surgery. By facilitating enhanced visualization and assessment of anastomotic perfusion and mechanical stability, this state-of-the-art technique may help mitigate the occurrence of anastomotic leaks while simultaneously improving patient outcomes. Notably, intravenous administration of ICG at a dose of 2.5 mg/kg, administered 24 hours prior to surgery, has been found to yield optimal visualization outcomes.

Indocyanine green fluorescent cholangiography improves the clinical effects of difficult laparoscopic cholecystectomy

BACKGROUND

Near-infrared fluorescent cholangiography (NIRFC) with indocyanine green (ICG) as the developer yields clear visualization of the extrahepatic bile ducts and is effective in identifying key structures. Here, we analyzed and compared the surgical outcomes of fluorescent and conventional laparoscopy in cholecystectomy of various difficulties and then assessed the value of NIRFC.

MATERIALS AND METHODS

This retrospective study collected clinical data from partial patients who underwent laparoscopic cholecystectomy (LC) at the Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University between 2020 and 2021. The study subjects were classified into ICG-assisted and white-light laparoscopy. Two cohorts with homogeneous baseline status were selected based on 1:1 ratio propensity score matching (PSM). Multivariate logistic regression analysis was performed to predict independent risk factors for LC difficulty. Thereafter, the matched cases were classified into difficult and easy subgroups by combining difficulty score and gallbladder disease type, and then the surgical outcomes of the two groups were compared.

RESULTS

This study included a total of 624 patients. The patients were classified into the ICG group (n = 218) and the non-ICG group (n = 218) after a 1:1 ratio PSM. Our data showed significant differences between the groups in operative time (P = 0.020), blood loss (P = 0.016), length of stay (P = 0.036), and adverse reaction (P = 0.023). Stratified analysis demonstrated that ICG did not significantly improve the surgical outcomes in simple cases (n = 208). On the other hand, in difficult cases (n = 228), NIRFC shortened operative time (P = 0.003) and length of stay (P = 0.015), reduced blood loss (P = 0.028) and drain placement rate (P = 0.015), and had fewer adverse reactions (P = 0.023). The data showed that five cases were converted to laparotomy while two cases had minor bile leaks in the non-ICG group. There was no bile duct injury (BDI) in all the cases. Furthermore, high BMI, history of urgent admission and abdominal surgery, palpable gallbladder, thickened wall, and pericholecystic collection were risk factors for surgical difficulty.

CONCLUSION

ICG-assisted NIRFC provides real-time biliary visualization. In complicated conditions such as acute severe inflammation, dense adhesions, and biliary variants, the navigating ability of fluorescence can enhance the operation progress, reduce the possibility of conversion or serious complications, and improve the efficiency and safety of difficult LC.

Real-time fluorescent cholangiography with indocyanine green in laparoscopic cholecystectomy: a randomized controlled trial to establish the optimal indocyanine green dose within 30 min preoperatively

PURPOSE

To establish the optimal dose of indocyanine green (ICG) to administer intravenously 30 min before laparoscopic cholecystectomy (LC).

METHODS

In this randomized controlled trial (RCT), patients undergoing LC for cholecystitis, cholelithiasis, and/or cholecystic polyps were randomized into four groups given four different ICG doses (0.025, 0.1, 0.25, 2.5 mg). Using OptoMedic endoscopy combined with a near-infrared fluorescent imaging system, we evaluated the fluorescence intensity (FI) of the common bile duct and liver at three timepoints: before surgical dissection of the cystohepatic triangle, before clipping of the cystic duct, and before closure. The bile duct-to-liver ratio (BLR) of the FI was analyzed to assess the cholangiography effect.

RESULTS

Sixty-four patients were allocated to one of four groups, with 40 patients included in the final analysis. Generally, with increasing ICG doses, the levels of FI in the bile duct and liver increased gradually at each of the three timepoints. Before surgical dissection of the cystohepatic triangle, 0.1-mg ICG showed the highest BLR (F = 3.47, p = 0.0259). Before clipping the cystic duct and before closure, the 0.025- and 0.1-mg groups showed a higher BLR than the 0.25- and 2.5-mg groups (p < 0.05). When setting the ideal cholangiography at a BLR ≥ 1, ≥ 3, or ≥ 5, the 0.1-mg group showed the highest qualified case number at the three timepoints.

CONCLUSIONS

The intravenous administration of 0.1-mg ICG, 30 min before LC, is significantly better for fluorescent cholangiography of the extrahepatic biliary structures before dissection and clipping of the cystohepatic triangle.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (ChiCTR) (ChiCTR2200057933).

Click-on fluorescence detectors: using robotic surgical instruments to characterize molecular tissue aspects

Fluorescence imaging is increasingly being implemented in surgery. One of the drawbacks of its application is the need to switch back-and-forth between fluorescence- and white-light-imaging settings and not being able to dissect safely under fluorescence guidance. The aim of this study was to engineer 'click-on' fluorescence detectors that transform standard robotic instruments into molecular sensing devices that enable the surgeon to detect near-infrared (NIR) fluorescence in a white-light setting. This NIR-fluorescence detector setup was engineered to be press-fitted onto standard forceps instruments of the da Vinci robot. Following system characterization in a phantom setting (i.e., spectral properties, sensitivity and tissue signal attenuation), the performance with regard to different clinical indocyanine green (ICG) indications (e.g., angiography and lymphatic mapping) was determined via robotic surgery in pigs. To evaluate in-human applicability, the setup was also used for ICG-containing lymph node specimens from robotic prostate cancer surgery. The resulting Click-On device allowed for NIR ICG signal identification down to a concentration of 4.77 × 10^-6 mg/ml. The fully assembled system could be introduced through the trocar and grasping, and movement abilities of the instrument were preserved. During surgery, the system allowed for the identification of blood vessels and assessment of vascularization (i.e., bowel, bladder and kidney), as well as localization of pelvic lymph nodes. During human specimen evaluation, it was able to distinguish sentinel from non-sentinel lymph nodes. With this introduction of a NIR-fluorescence Click-On sensing detector, a next step is made towards using surgical instruments in the characterization of molecular tissue aspects.

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.

Near-infrared fluorescence cholangiography at a very low dose of indocyanine green: quantification of fluorescence intensity using a colour analysis software based on the RGB color model

BACKGROUND

Indocyanine green (ICG) near-infrared fluorescence cholangiography (NIRF-C) is widely used to visualize the biliary tract during laparoscopic cholecystectomy (LC). However, the ICG dose and its dosing time vary in the literature so there is not a standard ICG protocol. The objectives of this descriptive prospective study were to demonstrate that NIRF-C at a very low dose of ICG provides good visualization of the extrahepatic biliary tree while avoiding hepatic hyperluminescence and to assess the surgeon-perceived benefit. Furthermore, another additional aim was quantifying the amount of ICG dye in the liver tissue and biliary tract through a green colour intensity (GCI) analysis according to red green blue (RGB) color model and correlating it to surgeon-perceived benefit.

METHOD

Forty-four patients were scheduled for LC. We recorded demographics, surgical indication, intraoperative details, adverse reactions to ICG, hepatic hyperluminescence, visualization of the cystic duct (CD), the common bile duct (CBD) and the cystic duct-bile duct junction (CDBDJ) before and after dissection of Calot's triangle, operation time, surgical complications and subjective surgeon data. For all procedures, a unique dose of 0.25 mg of ICG was administered intravenously during the anaesthetic induction. ICG NIRF-C was performed using the overlay mode of the VISERA ELITE II Surgical Endoscope in all surgeries. Video recordings of all 44 LC were reviewed. Using a color analysis software, the GCI of CBD versus adjacent liver tissue was calculated using RGB color model.

RESULTS

ICG NIRF-C was performed in all 44 cases. The mean operation time was 45 ± 15 min. There were no bile duct injuries (BDIs) or allergic reactions to ICG. The postoperative course was uneventful in all of cases. The mean postoperative hospital stay was 28 ± 4 h. ICG NIRF-C identified the CBD in 100% of the patients, the CD in 71% and the CDBDJ in 84%, with a surgeon satisfaction of 4/5 or 5/5 in almost 90% of surgeries based on a visual analogue scale (VAS). No statistically significant differences were found in the visualization of the biliary structures after the dissection of Calot's triangle in obese patients or with gallbladder inflammation. Furthermore, 25% of patients with a BMI ≥ 30, 27% of patients with a Nassar grade ≥ 3 and 21% of patients with gallbladder inflammation had a VAS score 5/5 compared to 6% of patients with a BMI < 30 (p = 0.215), 6% of patients with a Nassar grade < 3 (p = 0.083) and none of the patients without gallbladder inflammation (p = 0.037). Measured pixel GCI of CBD was higher than adjacent hepatic tissue for all cases regardless of the degree of gallbladder inflammation, the Nassar scale grades or the patient's BMI (p < 0.0001). In addition, a significant correlation was observed between surgeon-perceived benefit and the amount of ICG dye into the CBD according the RGB color model (p < 0.0001).

CONCLUSION

ICG NIRF-C at a very low dose of ICG (0.25 mg of ICG 20 min before surgery) enables the real-time identification of biliary ducts, thereby avoiding the hepatic hyperluminescence even in cases of obese patients or those with gallbladder inflammation.

Intracholecystic versus Intravenous Indocyanine Green (ICG) Injection for Biliary Anatomy Evaluation by Fluorescent Cholangiography during Laparoscopic Cholecystectomy: A Case-Control Study

(1) Background: Fluorescence cholangiography has been proposed as a method for improving the visualization and identification of extrahepatic biliary anatomy in order to possibly reduce injuries and related complications. The most common method of indocyanine green (ICG) administration is the intravenous route, whereas evidence on direct ICG injection into the gallbladder is still quite limited. We aimed to compare the two different methods of ICG administration in terms of the visualization of extrahepatic biliary anatomy during laparoscopic cholecystectomy (LC), analyzing differences in the time of visualization, as well as the efficacy, advantages, and disadvantages of both modalities. (2) Methods: A total of 35 consecutive adult patients affected by acute or chronic gallbladder disease were enrolled in this prospective case−control study. Seventeen patients underwent LC with direct gallbladder ICG injection (IC-ICG) and eighteen subjects received intravenous ICG administration (IV-ICG). (3) Results: The groups were comparable with regard to their demographic and perioperative characteristics. The IV-ICG group had a significantly shorter overall operative time compared to the IC-ICG group (p = 0.017). IV-ICG was better at delineating the duodenum and the common hepatic duct compared to the IC-ICG method (p = 0.009 and p = 0.041, respectively). The cystic duct could be delineated pre-dissection in 76.5% and 66.7% of cases in the IC-ICG and IV-ICG group, respectively, and this increased to 88.2% and 83.3% after dissection. The common bile duct could be highlighted in 76.5% and 77.8% of cases in the IC-ICG and IV-ICG group, respectively. Liver fluorescence was present in one case in the IC-ICG group and in all cases after IV-ICG administration (5.8% versus 100%; p < 0.0001). (4) Conclusions: The present study demonstrates how ICG-fluorescence cholangiography can be helpful in identifying the extrahepatic biliary anatomy during dissection of Calot’s triangle in both administration methods. In comparison with intravenous ICG injection, the intracholecystic ICG route could provide a better signal-to-background ratio by avoiding hepatic fluorescence, thus increasing the bile duct-to-liver contrast.

Intraoperative fluorescence molecular imaging accelerates the coming of precision surgery in China

Purpose

China has the largest cancer population globally. Surgery is the main choice for most solid cancer patients. Intraoperative fluorescence molecular imaging (FMI) has shown its great potential in assisting surgeons in achieving precise resection. We summarized the typical applications of intraoperative FMI and several new trends to promote the development of precision surgery.

Methods

The academic database and NIH clinical trial platform were systematically evaluated. We focused on the clinical application of intraoperative FMI in China. Special emphasis was placed on a series of typical studies with new technologies or high-level evidence. The emerging strategy of combining FMI with other modalities was also discussed.

Results

The clinical applications of clinically approved indocyanine green (ICG), methylene blue (MB), or fluorescein are on the rise in different surgical departments. Intraoperative FMI has achieved precise lesion detection, sentinel lymph node mapping, and lymphangiography for many cancers. Nerve imaging is also exploring to reduce iatrogenic injuries. Through different administration routes, these fluorescent imaging agents provided encouraging results in surgical navigation. Meanwhile, designing new cancer-specific fluorescent tracers is expected to be a promising trend to further improve the surgical outcome.

Conclusions

Intraoperative FMI is in a rapid development in China. In-depth understanding of cancer-related molecular mechanisms is necessary to achieve precision surgery. Molecular-targeted fluorescent agents and multi-modal imaging techniques might play crucial roles in the era of precision surgery.

Total robotic choledochal cyst excision with Roux-en-Y hepaticojejunostomy in adults

INTRODUCTION

Choledochal cyst (CDC) excision with bilio-enteric anastomosis has been reported by a laparoscopic approach. With the advent of robotic surgery, it is likely to simplify the performance of such complex procedures. Herein, we present our technique of total robotic CDC excision with intra-corporeal Roux-en-Y hepaticojejunostomy (RYHJ).

METHODS

The patient was placed in a reverse Trendelenburg position. The robotic ports were placed in a "C"-shaped manner, with the camera port placed ~2 cm below the umbilicus. A 12-mm assistant port was placed in between the camera and the left-sided robotic port. Robotic dissection and excision of extrahepatic part CDC were performed, and subsequently, intra-corporeal robotic RYHJ with jejunojejunostomy was completed. Intra-operatively, indocyanine green dye was used to delineate the biliary anatomy and to check the anastomotic integrity.

RESULTS

All three patients were female with a median age of 21 (18-34) years. Two patients had type IVa, and one had a mixed variant of type I(C) with type VI. The median operative time was 420 min, whereas docking and console time was 22 (20-25) min and 400 (360-450) min, respectively. The median blood loss and length of hospital stay were 50 (50-100) ml and 6 (5-6) days, respectively. One patient has mild acute pancreatitis in the post-operative period, which was managed conservatively.

CONCLUSION

Robotic CDC excision and reconstruction seem to be a safe, feasible, and effective surgical option that provides the benefits of minimal access surgery but also greatly aids in complex dissection and reconstruction.

Feasibility and educational value of fluorescence cholangiography in laparoscopic cholecystectomy

INTRODUCTION

Near-infrared fluorescence cholangiography during a laparoscopic cholecystectomy has become widely accepted as a useful auxiliary tool to visualize the extrahepatic biliary structures. We investigated the feasibility and educational value of a method with longer interval between the administration of indocyanine green and the imaging of these structures.

METHODS

Approximately 18 hours before their surgery, patients (n = 51) were intravenously administered 0.25 mg/kg of indocyanine green. Each laparoscopic cholecystectomy was performed under fluorescence imaging in combination with white-light imaging. Operative outcomes including visualization of the extrahepatic biliary structures and operative time were compared between the patients on whom board-certified surgeons operated (feasibility phase; n = 18) and the patients on whom a surgery resident operated (educational phase; n = 33).

RESULTS

There were no adverse events related to the longer interval method. The visualization rates of extrahepatic biliary structures were comparable between the two phases. Both the mean time to divide the cystic duct and the mean time to remove the gallbladder in the educational phase were significantly longer than those in the feasibility phase (68.2 vs 24.4 minutes and 30.2 vs 15.8 minutes, P < .001 each). There was no significant difference in other operative outcomes. The operative time learning curve did not decrease with a resident's experience.

CONCLUSIONS

Fluorescence cholangiography with the longer interval method was feasible and could identify the extrahepatic biliary structures irrespective of the surgeon's experience; however, it did not decrease the operative time with experience.

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.

Intraoperative indocyanine green-visualization in a difficult to localize central cholangiocarcinoma - A case report

INTRODUCTION AND IMPORTANCE

Near infrared fluorescence imaging with indocyanine green (ICG) can facilitate the intraoperative tumour localization and therefore a complete resection. Cholangiocarcinoma is an aggressive tumour and complete resection improves the outcome. Therefore, it is necessary to localize the tumour exactly but the translation of the preoperative imaging into the intraoperative setting can be difficult based only on sonography, computed tomography or magnetic resonance imaging. CASE PRESENTATION/CLINICAL FINDINGS AND INVESTIGATIONS/INTERVENTIONS AND OUTCOME: In this case a hepatic lesion suspicious for cholangiocarcinoma was discovered accidentally. Further diagnostics were unable to prove the diagnosis, therefore right hepatectomy was recommended and performed. Preoperatively ICG was administered and near infrared imaging was used intraoperatively clearly localizing the tumour, thus facilitating the resection. The intra- and postoperative course was uneventful.

RELEVANCE AND IMPACT

This case report supports the very promising intraoperative use of fluorescence imaging for the localization of superficial hepatic tumours. Timing and correct administration of ICG is important.