Optimal timing of preoperative indocyanine green administration for fluorescent cholangiography during laparoscopic cholecystectomy using the PINPOINT® Endoscopic Fluorescence Imaging System

The application of real-time indocyanine green fluorescence cholangiography in laparoscopic living donor left lateral sectionectomy

Background

The judgment of the division point of the bile duct has always been one of the difficulties of laparoscopic left lateral sectionectomy (LLLS). The purpose of this study was to assess the effects of indocyanine green (ICG) fluorescence cholangiography during LLLS on the occurrence of biliary complications in both donors and recipients. The optimal dose and injection time of ICG were also investigated.

Methods

This is a retrospective cohort study. From October 2016 to December 2022, the clinical data of 103 donors who underwent LLLS and relevant recipients were retrospectively analyzed. According to whether ICG fluorescence cholangiography was used, they were divided into a non-ICG group (n=46) and an ICG group (n=57). Biliary complications were observed and the optimal dose and injection time of ICG were explored.

Results

Three donors in the non-ICG group suffered from bile leakage. Four grafts had multiple bile duct openings and biliary complications were observed in the relevant recipients who received these grafts in the non-ICG group. Two recipients had bile leakage, and the other two had biliary stenosis. There was no biliary complications both in donors and recipients in the ICG group. The fluorescence intensity of the liver was 108.1±17.6 at a dose of 0.004 mg/kg 90 minutes after injection, significantly weaker than that at 0.05 mg/kg 30 minutes (200.3±17.6, P=0.001) and 90 minutes after injection (140.2±15.4, P=0.001). The fluorescence intensity contrast value at a dose of 0.004 mg/kg was stronger than that at 0.05 mg/kg, both measured 90 minutes after injection (0.098±0.032 vs. 0.078±0.022, P=0.021).

Conclusions

ICG fluorescence cholangiography is safe and feasible in LLLS. It reduces biliary complications in both donors and recipients. The optimal ICG dose was 0.004 mg/kg, and 90 minutes after injection was the best observation time. ICG fluorescence cholangiography is recommended for routine use in LLLS.

Role of indocyanine green-guided near-infrared fluorescence imaging in identification of the cause of neonatal cholestasis

To evaluate the efficacy and safety of indocyanine green (ICG)-guided near-infrared fluorescence (NIRF) imaging during surgery to diagnose the cause of neonatal cholestasis (NC). Data on NC patients who underwent both NIRF with ICG and conventional laparoscopic bile duct exploration (the gold standard) at our institute from January 2022 to December 2022 were retrospectively analyzed. The patients' baseline characteristics and liver function outcomes were collected and analyzed, and the diagnostic consistency was compared between the 2 methods. In total, 16 NC patients were included in the study, comprising 8 (50%) male and 8 (50%) female patients, ranging in age from 42 to 93 days, with a median age of 54.4 ± 21 days. During surgery, all the patients underwent NIRF with ICG, followed by conventional laparoscopic bile duct exploration. Finally, 15 of the patients were diagnosed with biliary atresia (BA) (1 with type-I BA, and 14 with type-II BA). The other patient was diagnosed with cholestasis. The diagnostic results from fluorescence imaging with ICG were consistent with those from conventional laparoscopic bile duct exploration. ICG-guided NIRF is associated with an easy operation, less trauma, and good safety. Also, its diagnostic accuracy is similar to conventional laparoscopic bile duct exploration.

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.

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.

Biliary Anatomy Visualization and Surgeon Satisfaction Using Standard Cholangiography versus Indocyanine Green Fluorescent Cholangiography during Elective Laparoscopic Cholecystectomy: A Randomized Controlled Trial

Background: Intraoperative biliary anatomy recognition is crucial for safety during laparoscopic cholecystectomy, since iatrogenic bile duct injuries represent a fatal complication, occurring in up to 0.9% of patients. Indocyanine green fluorescence cholangiography (ICG-FC) is a safe and cost-effective procedure for achieving a critical view of safety and recognizing early biliary injuries. The aim of this study is to compare the perioperative outcomes, usefulness and safety of standard intraoperative cholangiography (IOC) with ICG-FC with intravenous ICG. Methods: Between 1 June 2021 and 31 December 2022, 160 patients undergoing elective LC were randomized into two equal groups: Group A (standard IOC) and group B (ICG-FC with intravenous ICG). Results: No significant difference was found between the two groups regarding demographics, surgery indication or surgery duration. No significant difference was found regarding the visualization of critical biliary structures. However, the surgeon satisfaction and cholangiography duration presented significant differences in favor of ICG-FC. Regarding the inflammatory response, a significant difference between the two groups was found only in postoperative WBC levels. Hepatic and renal function test results were not significantly different between the two groups on the first postoperative day, except for direct bilirubin. No statistically significant difference was noted regarding 30-day postoperative complications, while none of the complications noted included bile duct injury events. Conclusions: ICG-FC presents equivalent results to IOC regarding extrahepatic biliary visualization and postoperative complications. However, more studies need to be performed in order to standardize the optimal dose, timing and mode of administration.

Near-infrared indocyanine green fluorescent cholangiography in urgent and emergency laparoscopic cholecystectomy: a preliminary study after propensity score-matched study

INTRODUCTION

Bile duct injury is a major complication of laparoscopic cholecystectomy (LC). Indocyanine green near-infrared fluorescence cholangiography (ICG-NIFC) is a well-recognized technique who provides an intraoperative mapping of the biliary system.

METHODS

All patients underwent urgent LC and randomly divided into two groups: in one group, only white light imaging was used and, in the ICG group, ICG was used. Due to the heterogeneity of our groups, a PSM was performed with a 1:1 PSM cohort.

RESULTS

The use of ICG clearly decreases the operation time (p value 0.002). The overall rate of intra- and post- operative complications was 4.17% and 15.8% respectively. Post-operative biliary duct injury trend decreases in ICG group and after the homogenization of the 2 cohorts, the intra- and post- operative complications (including vascular and biliary duct injury) results changed with a highest rate of complication in the cohort with no-ICG administration. The use of NIFC demonstrated a protective effect against intra- and post- operative complications and biliary duct injury (HR 0.037, p value 0.337 and HR 0.039, p value 0.647; HR 0.288; p value 0.05 and HR 0.635; p value 0.687, respectively).

CONCLUSIONS

The intra-operative use of NIFC showed a trend in the reduction of the rate of intra- and post-operative complications, the duration of surgery, and the length of hospital stay. ICG is a highly safe approach to urgent and emergency LC, as for elective LC, and could lead the surgeon to conduct the procedure more efficiently.

Efficacy and outcome of indocyanine green-based intraoperative cholangiography using near-infrared fluorescence imaging: A prospective study

INTRODUCTION

The most dreaded complication during laparoscopic cholecystectomy still remains to be injury to the common bile duct. The primary cause for bile duct injury during LC is misinterpretation of the biliary anatomy. Intra-operative cholangiography was introduced as a means of reducing the chances of biliary injury, done using Fluoroscopic imaging or Near-infrared fluorescence imaging method. NIRF is one of the most popular imaging methods in biomedical sciences. Indocyanine Green is sterile and water soluble which completely binds to albumin and is excreted in bile.

PATIENTS AND METHODS

This prospective study was conducted among 70 patients between July 2020 and December 2021. Subjects were administered 5mg of ICG dye pre-operatively and procedure performed using Karl Storz HD image S1 system with a D-light P light source for NIRF imaging.

RESULTS

The average duration of surgery was 58.10 minutes. After calot's dissection, the CBD was visualized in 88.71 % patients, with a mean time to visualization at 26.33 minutes. The cystic duct was visualized in 87.3% cases with a mean time of visualization of 32.10 minutes. The hepatic duct was visualized in 28.57% and the hepatic duct-CBD confluence was visualized in 34.28% patients.

CONCLUSION

Near infrared imaging based intra-operative cholangiography, using Indocyanine Green dye, during Lap. Cholecystectomy is an easy, useful and inexpensive method of visualizing the biliary ductal anatomy.

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).

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.

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).

Indocyanine green (ICG) fluorescent cholangiography in laparoscopic cholecystectomy: Simplifying time and dose

BACKGROUND

This article aims to analyze and to simplify the optimal dose and time of intravenous indocyanine green (ICG) administration to achieve the identification of the cystic duct and the common bile duct (CBD).

METHODS

A consecutive series of 146 patients was prospectively analyzed and divided into three groups according to the time of ICG administration: at induction of anesthesia group (20-30 min); hours before group (between 2 and 6 h); and the day before group (≥6 h); and two groups according to the dose of ICG: 1 cc (2.5 mg) or weight-based dose (0.05 mg/kg).

RESULTS

The CBD was better visualized in the at induction of anesthesia group (85.4%), in the hours before group (97.1%) (p = 0.002) and in the 1cc group (p = 0.011). When we analyzed the 1 cc group (n = 126) a greater visualization of the CBD was observed in the at induction of anesthesia group (86.7%) and in the hours before group (97.1%) (p = 0.027).

CONCLUSION

Due to its simplicity and reproducibility, we suggest a dose of 2.5 mg administered 2-6 h before the procedure is the optimal. However, ICG administered 30 min prior to the surgery is enough for adequate visualization of biliary structures.

Application of Intraoperative Fluorescence Imaging with Indocyanine Green in the Difficult Gallbladder: A Comparative Study between Indocyanine Green-Guided Fluorescence Cholangiography and Conventional Surgery

Background: In the difficult gallbladder, the rate of bile duct injury (BDI) remains high. To lessen iatrogenic biliary injury, we attempted to utilize indocyanine green (ICG)-guided fluorescence cholangiography during surgery to illuminate the extrahepatic biliary tract. Materials and Methods: According to admission criteria, 38 patients were diagnosed with difficult gallbladder and underwent percutaneous transhepatic gallbladder drainage (PTGBD). Consecutive patients who underwent ICG-assisted laparoscopic biliary surgery (n = 18, ICG group) or conventional laparoscopic biliary surgery (n = 20, white light [WL group) were enrolled in this study. ICG group received ICG fluorescent cholangiography via PTGBD tube during operation; 16 cases of laparoscopic cholecystectomy (LC) and 2 cases of LC plus laparoscopic common bile duct exploration (LC+LCBDE) were performed by fluorescent laparoscopy. In the WL group, 16 cases of LC, 1 case of laparoscopic subtotal cholecystectomy (LSC), and 3 cases of LC+LCBDE were performed under white light without ICG. Result: The biliary system was successfully established in the ICG group. Compared with the WL group, the anatomy of the Calot's triangle with severe abdominal adhesion or local inflammatory edema was more clearly displayed by fluorescence. Laparoscopic surgery was completed in both groups without conversion to laparotomy. There were no significant differences in surgery-related complications (P = .232) and postoperative hospital stay (P = .074) between the two groups. However, compared with the WL group, the ICG group had less intraoperative blood loss (P = .002) and shorter operation duration (P = .006). Conclusion: ICG fluorescence cholangiography has good clinical application value in the difficult gallbladder, which can avoid iatrogenic BDI, reduce surgery-related complications and intraoperative blood loss, and shorten the duration of surgery.

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.

Study of Learning Curve in a Surgeon for Near-Infrared Fluorescence Cholangiography During Laparoscopic Cholecystectomy-A Retrospective Evaluation

BACKGROUND

Near-infrared indocyanine green fluorescence cholangiography (NIRF) has shown promising results on delineating extra-hepatic biliary anatomy during laparoscopic cholecystectomy to avoid bile duct injury. However its routine usage remains in question. In this study, the technique was evaluated further with learning curve estimation and learning factors were observed.

METHODS

One hundred ninety-nine cases which underwent laparoscopic cholecystectomy for acute or chronic cholecystitis within a 2-year period including 51 cases with initial use of NIRF by 2 surgeons were studied retrospectively. The learning curve was evaluated for a surgeon as primary objective. A case-matched comparison of the operative time between NIRF and conventional group, in terms of acute and chronic cholecystitis was also conducted as a secondary calculation.

RESULTS

Learning curve was evaluated with 61% learning rate for NIRF experience. Cysto-biliary junction non-illuminated cases under fluorescent view, had mean operative time of 80.83 ± 22.82 min, which was shorter than the cysto-biliary junction illuminated cases. The NIRF group exhibited longer operative time compared with the conventional group with mean difference of 34.39 min (significant at P < .05).

CONCLUSIONS

While the initial learning phase might be affected by surgeons' behavior and attitude, our results may provide a reference to learn at one's own pace and to employ NIRF teaching strategies during surgical training programs to overcome the initial phase during training period itself and facilitate universal achievement.

Routine use of ICG to enhance operative safety in emergency laparoscopic cholecystectomy: a randomized controlled trial

OBJECTIVE

To test the hypothesis that ICG fluorescence cholangiography (ICG-FC) helps to identify critical structures during laparoscopic cholecystectomy (LC) and hence reduce biliary injuries and conversions. In LC, biliary injury and conversion often happen if the biliary anatomy is misidentified.

METHODS

This was a single-center randomized controlled trial from 2017 to 2019. Patients with acute cholecystitis requiring LC were assessed for eligibility for the trial. Patients in the trial were randomized to undergo either conventional LC (conventional arm) or LC with ICG-FC (ICG arm). Conversion rate and biliary injury incidence were outcome measures.

RESULTS

Totally 92 patients participated (46 patients in each arm). The median age was 61 years in both arms (p = 0.472). The conventional arm had 22 men and 24 women; the ICG arm had 24 men and 22 women (p = 0.677). The two arms were comparable in all perioperative parameters. The time from ICG injection to surgery was 67 (16-1150) min. Both arms had an 8.7% conversion rate (p = 1.000). The median operative time was 140.5 min in the conventional arm and 149.5 min in the ICG arm (p = 0.086). The complication rate was 15.2% in the former and 10.9% in the latter (p = 0.536), and both had a 2.2% bile leakage rate. The median hospital stay was 3.5d in the former and 4.0d in the latter (p = 0.380).

CONCLUSION

ICG-FC did not make any difference in conversion or complication rate. Its routine use in LC is questionable. However, it may be helpful in difficult cholecystectomies and may be used as an adjunct.

TRIAL REGISTRATION

The trial was registered with the Institutional Review Board of University of Hong Kong/Hospital Authority Hong Kong West Cluster ( http://www.med.hku.hk/en/research/ethics-and-integrity/human-ethics ). Registration number: UW17-492.

Efficacy of indocyanine green (ICG) fluorescent cholangiography to improve intra-operative visualization during laparoscopic cholecystectomy in pediatric patients: a comparative study between ICG-guided fluorescence and standard technique

BACKGROUND

In the last few years, indocyanine green (ICG) fluorescent cholangiography (FC) has been adopted to perform intra-operative biliary mapping during laparoscopic cholecystectomy (LC). This study aimed to compare the results of LC with and without use of ICG-FC.

METHODS

All LC operated from June 2017 to June 2021 in our unit were retrospectively reviewed. Pre-operative workup included ultrasonography to assess dilation of main biliary tree. The ICG dosage was 0.35 mg/kg and the median timing of administration was 15.5 h pre-operatively. We evaluated, analyzing videorecorded procedures, 3 parameters in both groups: the total operative time (T1), the time of cystic duct isolation, clipping and sectioning (T2), and the time of gallbladder removal from hepatic fossa (T3).

RESULTS

Forty-three LC were operated in the study period: 22 using standard technique (G1) and 21 using ICG-FC (G2). There were 27 girls and 16 boys, with median age at surgery of 11.5 years (range 7-17) and median weight of 47 kg (range 31-110). No conversions were reported in our series. In all ICG cases (except one patient under therapy with phenobarbital) the biliary tree was perfectly visualized during dissection. Intra-operative complications occurred in 3 G1 patients (13.6%): 2 bleedings from the Calot's triangle and 1 bleeding from the liver bed during the gallbladder removal. LC was significantly faster in G2 than in G1 (p = 0.001). In fact, the parameters analyzed (T1, T2, T3) were all significantly greater in G1 than in G2 (p = 0.001).

CONCLUSIONS

Based upon our experience, we strongly recommend the use of ICG-FC in all pediatric patients undergoing LC. ICG-guided fluorescence provided an excellent real-time visualization of the extrahepatic biliary tree and allowed faster and safer dissection, minimizing the risk of bile duct injuries. Furthermore, ICG use was clinically safe, with no adverse reactions to the product.

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.

Indocyanine green (ICG) fluorescent cholangiography during laparoscopic cholecystectomy using RUBINA™ technology: preliminary experience in two pediatric surgery centers

Background

Recently, we reported the feasibility of indocyanine green (ICG) near-infrared fluorescence (NIRF) imaging to identify extrahepatic biliary anatomy during laparoscopic cholecystectomy (LC) in pediatric patients. This paper aimed to describe the use of a new technology, RUBINA™, to perform intra-operative ICG fluorescent cholangiography (FC) in pediatric LC.

Methods

During the last year, ICG-FC was performed during LC using the new technology RUBINA™ in two pediatric surgery units. The ICG dosage was 0.35 mg/Kg and the median timing of administration was 15.6 h prior to surgery. Patient baseline, intra-operative details, rate of biliary anatomy identification, utilization ease, and surgical outcomes were assessed.

Results

Thirteen patients (11 girls), with median age at surgery of 12.9 years, underwent LC using the new RUBINA™ technology. Six patients (46.1%) had associated comorbidities and five (38.5%) were practicing drug therapy. Pre-operative workup included ultrasound (n = 13) and cholangio-MRI (n = 5), excluding biliary and/or vascular anatomical anomalies. One patient needed conversion to open surgery and was excluded from the study. The median operative time was 96.9 min (range 55–180). Technical failure of intra-operative ICG-NIRF visualization occurred in 2/12 patients (16.7%). In the other cases, ICG-NIRF allowed to identify biliary/vascular anatomic anomalies in 4/12 (33.3%), including Moynihan's hump of the right hepatic artery (n = 1), supravescicular bile duct (n = 1), and short cystic duct (n = 2). No allergic or adverse reactions to ICG, post-operative complications, or reoperations were reported.

Conclusion

Our preliminary experience suggested that the new RUBINA™ technology was very effective to perform ICG-FC during LC in pediatric patients. The advantages of this technology include the possibility to overlay the ICG-NIRF data onto the standard white light image and provide surgeons a constant fluorescence imaging of the target anatomy to assess position of critical biliary structures or presence of anatomical anomalies and safely perform the operation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-021-08596-7.

The role of indocyanine green cholangiography in minimally invasive surgery

INTRODUCTION

Near-infrared fluorescent cholangiography (NIFC) using indocyanine green (ICG) is increasingly used to aid in the identification of extrahepatic biliary anatomy. The use of ICG cholangiography for laparoscopic cholecystectomy is suggested to be safe and feasible. This article aimed at reviewing the dosage and timing of the intravenous administration of ICG, its efficacy and potential usage.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches were performed using the key words "fluorescent cholangiography," "ICG cholangiography," "near-infrared fluorescent cholangiography" and "laparoscopic cholecystectomy" to identify relevant articles published in English during the years of 2010 to 2020. Reference lists from the articles were reviewed to identify additional pertinent articles.

EVIDENCE SYNTHESIS

Several factors can influence the quality of the fluorescence imaging, including the dose and timing of ICG injection, liver function, the thickness of fatty tissue and the presence of inflamed tissues due to acute pathology. Various devices tested also have a different sensitivity to the fluorescence signal. RCTs showed fluorescence cholangiography were comparable to traditional intraoperative cholangiogram in visualizing the extrahepatic biliary anatomy. However, there is still no consensus in the dosing of ICG and the time interval between ICG injection and detection of biliary fluorescence. Fluorescence cholangiography's ability to enhance such visualization can potentially reduce bile duct injury risks and shorten the operative time. However, no valuable data for bile duct injury prevention or detection could be retrieved.

CONCLUSIONS

NIFC is demonstrated as a safe, non-irradiating technique to identify and aid in the visualization of extrahepatic biliary anatomy. Laparoscopic cholecystectomy with real-time NIFC enables a better visualization and identification of biliary anatomy and therefore it is potentially as a means of increasing the safety of laparoscopic cholecystectomy. Whether this translates into reducing complication rates must still be determined. The dosage and timing of the intravenous administration of ICG relative to the operative procedure still requires optimization to ensure reliable images.

Indocyanine green administration a day before surgery may increase bile duct detectability on fluorescence cholangiography during laparoscopic cholecystectomy

BACKGROUND

The optimal indocyanine green (ICG) administration protocol for fluorescence cholangiography during laparoscopic cholecystectomy (LC) has yet to be determined.

METHODS

A prospective study including 20 cases of ICG fluorescence-navigated LC was conducted. Accordingly, the first 10 patients were administered 2.5 mg of ICG on the day of surgery after intubation (surgery-day group), while the remaining 10 consecutive patients were administered 0.25 mg/kg of ICG on the evening before surgery (one-day-before group). Fluorescence intensity (FI) of each tissue and FI ratios were then compared between both groups.

RESULTS

The median interval between observation and ICG administration was 27 minutes and 16 hours 24 minutes in the surgery-day and one-day-before group, respectively. Although FI values for the common bile duct (CBD), liver, and hepatoduodenal ligament (HDL) were significantly lower in the one-day-before group than in the surgery-day group, CBD- , 0.6-1.2 vs 2.5, 0.9 = -4.8; P < .001), and CBD-HDL contrast (1.7, 1.4-2.4 vs 2.3, 1.5-13.3; P = .038) were significantly higher in the one-day-before group than in the surgery-day group.

CONCLUSION

ICG administration a day before LC may offer better CBD background contrast compared to administration just prior to surgery.

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

BACKGROUND

The dose and dosing time of indocyanine green (ICG) vary among fluorescence cholangiography (FC) studies. The purpose of this prospective, randomized, exploratory clinical trial was to optimize the dose and dosing time of ICG.

METHODS

PubMed was searched to determine the optimal dose. To optimize the dosing time of ICG, a clinical trial was designed with two parts. The first part included patients with T tubes for more than 1 month. After the patient was injected with ICG, bile was collected at 10 time points to explore the change and trends of bile fluorescence intensity (FI). In addition, the results of the first experiment were used to setup a randomized controlled trial (RCT) that aimed to find the optimal dosing timing for ICG injections for laparoscopic cholecystectomy (LC). During surgery, imaging data were collected for analysis.

RESULTS

After performing a systematic review, the ICG injection dose for each patient in the clinical trial was 10 mg. Five patients were included in the first part of the study. Bile collected 8 h after ICG injection had a higher FI than bile collected at other time points (p < 0.05), and the FI of bile collected 20 h after ICG injection was nearly zero. In the second part of the experiment, 4 groups of patients (6 patients per group) were injected with 10 mg ICG at 8, 10, 12 and 14 h prior to surgery. The distribution of bile duct FI (p = 0.001), liver FI (p < 0.001), and common bile duct (CBD)-to-liver contrast (p = 0.001) were not the same in each group. Further analysis with the Bonferroni method revealed the following: (1) the FI of the CBD in the 8 h group was significantly different from that in the 14 h group (adjusted p < 0.001); (2) the liver FI of the 8 h group was higher than that of the 10 h group (adjusted p = 0.042) and the 14 h group (adjusted p < 0.001); and (3) the CBD-to-liver contrast of the 8 h group was lower than that of the 10 h group (adjusted p = 0.013) and the 14 h group (adjusted p = 0.001).

CONCLUSION

ICG FC enables the real-time identification of extrahepatic bile ducts. The optimal effect of FC can be achieved by performing 10 mg ICG injections 10 to 12 h prior to surgery.

Fluorescence or X-ray cholangiography in elective laparoscopic cholecystectomy: a randomized clinical trial

BACKGROUND

Safe laparoscopic cholecystectomy may necessitate biliary imaging, and non-invasive fluorescence cholangiography may have advantages over contrast X-ray cholangiography. This trial compared fluorescence and X-ray cholangiography for visualization of the critical junction between the cystic, common hepatic and common bile ducts.

METHODS

This non-inferiority blinded RCT included patients who had either intraoperative fluorescence cholangiography using 0·05 mg/kg indocyanine green or X-ray cholangiography during elective laparoscopic cholecystectomy.

RESULTS

Between March 2015 and August 2018, a total of 120 patients were randomized (60 in each group). There were no drop-outs and 30-day follow-up data were available for all patients. In intention-to-treat analysis, there was no difference between the fluorescence and X-ray cholangiography groups in ability to visualize the critical junction (49 of 60 versus 51 of 60 respectively; P = 0·230). Fluorescence cholangiography was faster by a few minutes: median 2·0 (range 0·5-5·0) versus 4·8 (1·3-17·6) min (P < 0·001).

CONCLUSION

Fluorescence cholangiography was confirmed to be non-inferior to X-ray cholangiography in visualizing the critical junction during laparoscopic cholecystectomy. Registration number: NCT02344654 ( http://www.clinicaltrials.gov).

Clipping of an anterior spinal artery aneurysm using an endoscopic fluorescence imaging system for craniocervical junction epidural arteriovenous fistula: technical note

The authors report the case of a 78-year-old man with a craniocervical junction epidural arteriovenous fistula who presented with subarachnoid hemorrhage from a ruptured anterior spinal artery (ASA) aneurysm. Because endovascular embolization was difficult, a posterolateral approach was chosen and a novel endoscopic fluorescence imaging system was utilized to clip the aneurysm. The fluorescence imaging system provided clear and magnified views of the ventral spinal cord simultaneously with the endoscope-integrated indocyanine green videoangiography, which helped safely obliterate the ASA aneurysm. With the aid of this novel imaging system, surgeons can appreciate and manipulate complex vascular pathologies of the ventral spinal cord through a posterolateral approach, even when the lesion is closely related to the ASA.

Technical Note: Are Currently Used Measurements of Fluorescence Intensity in Near Infrared Fluorescence Imaging During Laparoscopic Cholecystectomy Comparable?

Aims: To investigate whether different calculation methods to express fluorescence intensity (FI) as target-to-background (BG) ratio are comparable and which method(s) match with human perception. Materials and Methods: Comparison of three calculation methods from current literature (OsiriX^®, ImageJ^®, and Photoshop^®) to objectify FI during laparoscopic cholecystectomy measured at the exact same locations within recorded images of two categories: ex vivo and in vivo. Currently applied formulas to present FI in relation to the BG signal are compared with the subjective assessment by the human observers. These three formulas are Signal contrast = (FI in fluorescence regions-FI in BG)/255; Target-to-background ratio = (FI of target-FI of BG)/FI of BG; Signal-to-background ratio = FI of cystic duct/FI of liver and Target-to-background ratio = (FI of target-noise)/(FI of BG-noise). Results: In our evaluation OsiriX and ImageJ provided similar results, whereas OsiriX values were structurally slightly lower compared with ImageJ. Values obtained through Photoshop were less evidently related to those obtained with OsiriX and ImageJ. The formula Target-to-background ratio = (FI of target-noise)/(FI of BG-noise) was less corresponding with human perception compared with the other used formulas. Conclusions: FI results based on measurements using the programs OsiriX and ImageJ are similar, allowing for comparison of results between these programs. Results using Photoshop differ significantly, making direct comparison impossible. This is an important finding when interpreting study results. We propose to report both target and BG FI in articles, so that proper interpretation between articles can be made.