Near-infrared cholecysto-cholangiography with indocyanine green may secure cholecystectomy in difficult clinical situations: proof of the concept in a porcine model

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

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

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.

Near-infrared cholangiography can increase the chance of success in laparoscopic approaches to common bile duct stones, even with previous abdominal surgery

BACKGROUND

The treatment of common bile duct (CBD) stones with minimally invasive surgery (MIS) is more technical demanding than laparoscopic cholecystectomy (LC), especially in patients with history of previous abdominal surgery, cholangitis or cholecystitis. Near-infrared (NIR) cholangiography via systemic or biliary tree administration of indocyanine green (ICG), which enhances the visualization of the biliary tree anatomy, may increase the reassurance of CBD localization. The aim of this study was to identify the benefit of near-infrared cholangiography for laparoscopic common bile duct exploration (LCBDE).

METHODS

Three groups of CBD stone patients were included in this retrospective study depending on the surgical methods: 1) open choledocholithotomy (OCC), 2) laparoscopic choledocholithotomy (LCC), and 3) near-infrared cholangiography-assisted laparoscopic choledocholithotomy (NIR-CC). For the NIR-CC group, either 3 ml (concentration: 2.5 mg/mL) of ICG were intravenously administered or 10 ml (concentration: 0.125 mg/mL) of ICG were injected directly into the biliary tree. The enhancement rate of the cystic duct (CD), CBD, the upper and lower margin of the CBD were compared using white light image.

RESULTS

A total of 187 patients with a mean age of 68.3 years were included (OCC, n = 56; LCC, n = 110; NIR-CC, n = 21). The rate of previous abdominal surgery was significantly lower in the LCC group. The conversion rate was similar between the LCC and the NIR CC groups (p = 0.746). The postoperative hospital stay was significantly longer in the OCC group. No differences in morbidity and mortality were found between the three groups. In the NIR-CC group, the localization of CBD was as high as 85% compared to 24% with white light imaging.

CONCLUSIONS

Near-infrared cholangiography helps increase the chance of success in minimally invasive approaches to CBD stones even in patients with previous abdominal surgeries, without increasing the rate of conversion.

Navigated liver surgery: State of the art and future perspectives

BACKGROUND

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

DATA SOURCES

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

RESULTS

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

CONCLUSIONS

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

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.

Fluorescence-based cholangiography: preliminary results from the IHU-IRCAD-EAES EURO-FIGS registry

INTRODUCTION

Near-infrared fluorescence cholangiography (NIRF-C) is a popular application of fluorescence image-guided surgery (FIGS). NIRF-C requires near-infrared optimized laparoscopes and the injection of a fluorophore, most frequently Indocyanine Green (ICG), to highlight the biliary anatomy. It is investigated as a tool to increase safety during cholecystectomy. The European registry on FIGS (EURO-FIGS: www.euro-figs.eu ) aims to obtain a snapshot of the current practices of FIGS across Europe. Data on NIRF-C are presented.

METHODS

EURO-FIGS is a secured online database which collects anonymized data on surgical procedures performed using FIGS. Data collected for NIRF-C include gender, age, Body Mass Index (BMI), pathology, NIR device, ICG dose, ICG timing of administration before intraoperative visualization, visualization (Y/N) of biliary structures such as the cystic duct (CD), the common bile duct (CBD), the CD-CBD junction, the common hepatic duct (CHD), Visualization scores, adverse reactions to ICG, operative time, and surgical complications.

RESULTS

Fifteen surgeons (12 European surgical centers) uploaded 314 cases of NIRF-C during cholecystectomy (cholelithiasis n = 249, cholecystitis n = 58, polyps n = 7), using 4 different NIR devices. ICG doses (mg/kg) varied largely (mean 0.28 ± 0.17, median 0.3, range: 0.02-0.62). Similarly, injection-to-visualization timing (minutes) varied largely (mean 217 ± 357; median 57), ranging from 1 min (direct intragallbladder injection in 2 cases) to 3120 min (n = 2 cases). Visualization scores before dissection were significantly correlated, at univariate analysis, with ICG timing (all structures), ICG dose (CD-CBD), device (CD and CD-CBD), surgeon (CD and CD-CBD), and pathology (CD and CD-CBD). BMI was not correlated. At multivariate analysis, pathology and timing remained significant factors affecting the visualization scores of all three structures, whereas ICG dose remained correlated with HD visualization only.

CONCLUSIONS

The EURO-FIGS registry has confirmed a wide disparity in ICG dose and timing in NIRF-C. EURO-FIGS can represent a valuable tool to promote and monitor FIGS-related educational and consensus activities in Europe.

Fluorescent cholangiography with direct injection of indocyanine green (ICG) into the gallbladder: a safety method to outline biliary anatomy

PURPOSE

Near infrared cholangiography (NIRC) with indocyanine green (ICG) directly injected into the gallbladder is a novel technique to outline biliary anatomy. The purpose of this article is to analyze the usefulness and feasibility of NIRC as a safety method during laparoscopic cholecystectomies.

MATERIAL AND METHODS

A case-controlled study comparing 20 patients undergoing laparoscopic cholecystectomies with NIRC with direct injection of ICG into the gallbladder to 20 consecutive standard cholecystectomies. Operative time, length of stay, complications, conversion rates, and biliary injury were analyzed.

RESULTS

Both groups were comparable in epidemiological characteristics. In the ICG group fluorescent visualization of the junction of the Hartmann pouch and the whole cystic duct was achieved in 16 (80%) patients. Median surgical time was 65 (50-76) and 55 (45-71) min for the ICG and the control group, respectively (p = 0.113). There were no postoperative complications and no biliary duct injuries in any of the groups, and a patient from both groups underwent conversion to open surgery.

CONCLUSION

NIRC with direct injection of ICG into the gallbladder is a feasible method that is not time-consuming; it does not require a different learning curve from standard laparoscopic cholecystectomies and has no major complications described so far.

A meta-analysis of indocyanine green fluorescence image-guided laparoscopic cholecystectomy for benign gallbladder disease

BACKGROUND

This meta-analysis was conducted to evaluate the effectiveness and safety of indocyanine green fluorescence image-guided laparoscopic cholecystectomy for benign gallbladder disease.

METHODS

Clinical studies were retrieved from PubMed, Embase, Cochrane Library, Medline, and the Web of Science databases. Study-specific effect sizes and their 95 % confidence intervals (CIs) were combined to calculate the pooled values, using fixed-effects or random-effects models.

RESULTS

Eleven studies with combined total of 2221 patients were included. Compared to the control group, the indocyanine green fluorescence imaging-guided group experienced shorter operative time (standardized mean difference [SMD] = -0.30; 95 % CI = -0.45 - -0.15; P < 0.001), shorter biliary anatomy identification time (SMD = -2.34; 95 % CI = -2.58 - -2.10; P < 0.001), lower blood loss (SMD = -0.14; 95 % CI = -0.26 - -0.01; P = 0.035), higher success rate of biliary tract imaging (odds ratio [OR] = 2.37; 95 % CI = 1.09-5.12; P = 0.029), lower rate of conversion to open surgery (OR = 0.10; 95 % CI = 0.04 - 0.28; P < 0.001), shorter hospital stay (SMD = -0.23; 95 % CI = -0.39 - -0.06, P = 0.008), and lower biliary tract imaging costs (SMD = -247.88; 95 % CI, -274.31--221.45, P = 0.000). Postoperative complications did not differ between the groups.

CONCLUSION

This systematic review shows that indocyanine green fluorescence biliary tract imaging is a safe and feasible new way for biliary tract identification in laparoscopic cholecystectomy.

Fluorescence cholangiography enhances surgical residents’ biliary delineation skill for laparoscopic cholecystectomies

BACKGROUND

Laparoscopic cholecystectomy (LC) is a minimally invasive procedure, often performed by surgical residents (SRs). Fluorescence cholangiography (FC) enables real-time identification of biliary anatomy.

AIM

To investigate the benefit of FC for enhancing SRs’ identification skills.

METHODS

Prospective data was collected from January 2018 to June 2018 at our hospital. The study cohorts were the SRs (study group, n = 15) and the surgical staff (SS; control group, n = 9). Participants were assigned to watch videos of LCs with FC from five different patients who had gallbladder disease, and identify structures in the video clips (including cystic duct, common bile duct, common hepatic duct, and cystic artery), first without FC, and then with FC.

RESULTS

In the without-FC phase, the overall misidentification rate by SRs (21.7%) was greater than that of the SS (11.8%; P = 0.018), However, in the FC phase, the two groups did not significantly differ in misidentification rates (23.3% vs 23.3%, P = 0.99). Paired-structure analysis of the without-FC and with-FC phases for the SR group found a significantly higher misidentification rate in the without-FC phase than the with-FC phase (21.9% vs 10.9%; P < 0.01). However, misidentification rates in the with-FC phase did not significantly differ between SRs and SS.

CONCLUSION

FC enhanced identification skills of inexperienced surgeons during LC compared with conventional training. Combined with simulation-based video training, FC is a promising tool for enhancing technical and decision skills of trainees and inexperienced surgeons.

Extrahepatic cholangiography in near-infrared II window with the clinically approved fluorescence agent indocyanine green: a promising imaging technology for intraoperative diagnosis

Rationale: Biliary tract injury remains the most dreaded complication during laparoscopic cholecystectomy. New intraoperative guidance technologies, including near-infrared (NIR) fluorescence cholangiography with indocyanine green (ICG), are under comprehensive evaluation. Previous studies had shown the limitations of traditional NIR light (NIR-I, 700-900 nm) in visualizing the biliary tract structures in specific clinical situations. The aim of this study was to evaluate the feasibility of performing the extrahepatic cholangiography in the second NIR window (NIR-II, 900-1700 nm) and compare it to the conventional NIR-I imaging. Methods: The absorption and emission spectra, as well as fluorescence intensity and photostability of ICG-bile solution in the NIR-II window were recorded and measured. In vitro intralipid® phantom imaging was performed to evaluate tissue penetrating depth in NIR-I and NIR-II window. Different clinical scenarios were modeled by broadening the penetration distance or generating bile duct injuries, and bile duct visualization and lesion site diagnosis in the NIR-II window were evaluated and compared with NIR-I imaging. Results: The fluorescence spectrum of ICG-bile solution extends well into the NIR-II region, exhibiting intense emission value and excellent photostability sufficient for NIR-II biliary tract imaging. Extrahepatic cholangiography using ICG in the NIR-II window obviously reduced background signal and enhanced penetration depth, providing more structural information and improved visualization of the bile duct or lesion location in simulated clinical scenarios, outperforming the NIR-I window imaging. Conclusions: The conventional clinically approved agent ICG is an excellent fluorophore for NIR-II bile duct imaging. Fluorescence cholangiography with ICG in the NIR-II window could provide adequate visualization of the biliary tract structures with increased resolution and penetration depth and might be a valid option to increase the safety of cholecystectomy in difficult cases.

[Fluorescence-guided detection of lymph node metastases of gastrointestinal tumors]

A correct lymph node (LN) staging is essential in oncological surgery. Indocyanine green (ICG) near-infrared fluorescence (NIRF) guided sentinel lymph node (SLN) navigation is a relatively novel technique. The aim of this review is to analyze the impact of ICG-NIRF on identification of LN metastases of gastrointestinal tumors. The Scopus and PubMed/MEDLINE literature databases were searched and 20 studies were included. The ICG-NIRF navigation of LN has been shown to enable and improve LN detection in gastrointestinal tumors; however, the mean detection, sensitivity, accuracy and false negative rates show substantial variation. This could be due to both the heterogeneous techniques applied and to the low retention of ICG by lymph nodes. Fluorescence imaging to identify LN drainage is a promising tool to improve oncological outcomes. Nonetheless, the technique requires further development in terms of hardware, software and fluorophores, which are currently being investigated.

Routine near infra-red indocyanine green fluorescent cholangiography versus intraoperative cholangiography during laparoscopic cholecystectomy: a case-matched comparison

BACKGROUND

The aim is to evaluate safety and efficacy of near infra-red (NIR) indocyanine green (ICG) fluorescence structural imaging during laparoscopic cholecystectomy (LC) (Group A) and to compare perioperative data, including operative time, with a series of patients who underwent LC with routine traditional intraoperative cholangiography (IOC) (Group B).

METHODS

Forty-four patients with acute or chronic cholecystitis underwent NIR-ICG fluorescent cholangiography during LC. ICG was administered intravenously at different time intervals or by direct gallbladder injection during surgery. Fluorescence intensity and anatomy identification were scored according to a visual analogue scale between 1 (least accurate) and 5 (most accurate). Group B patients (n = 44) were chosen from a prospectively maintained database of patients who underwent LC with routine IOC, matched for age, sex, body mass index, and diagnosis with group A patients.

RESULTS

No adverse reactions were recorded. In group A, mean time between intravenous administration of ICG and surgery was 10.7 ± 8.2 (range 2-52) h. Administered doses ranged from 3.5 to 13.5 mg. Fluorescence was present in all cases, scoring ≥ 3 in 41 patients. Mean operative time was 86.9 ± 36.9 (30-180) min in group A and 117.9 ± 43.4 (40-220) min in group B (p = 0.0006). No conversion to open surgery nor bile duct injuries were observed in either group.

CONCLUSIONS

LC with NIR-ICG fluorescent cholangiography is safe and effective for early recognition of anatomical landmarks, reducing operative time as compared to LC with IOC, even when residents were the main operator. NIR-ICG fluorescent cholangiography was effective in patients with acute cholecystitis and in the obese. Data collection into large registries on the results of NIR-ICG fluorescent cholangiography during LC should be encouraged to establish whether this technique might set a new safety standard for LC.

Usability of Intraoperative Fluorescence Imaging with Indocyanine Green During Laparoscopic Cholecystectomy After Percutaneous Transhepatic Gallbladder Drainage

BACKGROUND

Patients with persistent symptoms of acute cholecystitis for >72 h who cannot undergo urgent laparoscopic cholecystectomy (LC) often undergo percutaneous transhepatic gallbladder drainage (PTGBD) and delayed LC. However, intraoperative near-infrared fluorescence with indocyanine green (ICG) has recently become available in various surgical settings. Therefore, we evaluated the usability of intraoperative fluorescence imaging with ICG for LC after PTGBD in patients with acute cholecystitis.

METHODS

The preoperative and postoperative clinical characteristics of patients who underwent LC after PTGBD were retrospectively analyzed.

RESULTS

In total, 130 patients were reviewed. Intraoperative ICG fluorescence imaging was used in 39 (30.0%) patients, and none developed adverse reactions. Patients with ICG fluorescence imaging had a significantly shorter operative time (129 ± 46 vs. 150 ± 56 min, p = 0.0455), markedly lower conversion rate (2.6% vs. 22.0%, p = 0.0017), and lower proportion of subtotal cholecystectomy (0.0% vs. 6.6%, p = 0.0359) than patients without ICG fluorescence imaging. Independent risk factors for conversion to laparotomy during LC after PTGBD were the performance of PTGBD after 48 h from onset (OR 3.52; 95% CI 1.11-12.21; p = 0.0322), an unremoved PTGBD tube on LC (4.48, 1.46-15.00, p = 0.0084), and surgery without ICG (8.00, 1.28-159.47, p = 0.0231).

CONCLUSION

Intraoperative ICG fluorescence imaging produced better surgical outcomes without any adverse reactions. Early performance of PTGBD and intraoperative ICG fluorescence imaging can reduce the surgical difficulties in LC after PTGBD for acute cholecystitis.

The role of indocyanine green fluoroscopy for intraoperative bile duct visualization during laparoscopic cholecystectomy: an observational cohort study in 70 patients

Background

Bile duct injury is the most feared complication during laparoscopic cholecystectomy. Real-time intraoperative imaging using indocyanine green (ICG) might reduce the risk of bile duct injury by improving visualization of the biliary tree during laparoscopic cholecystectomy. We compared the outcomes of laparoscopic cholecystectomy in patients with and without real-time ICG.

Methods

A retrospective analysis of the data of patients undergoing laparoscopic cholecystectomy with and without ICG in a referral centre for minimally invasive surgery was performed. We hypothesized that laparoscopic cholecystectomy with real-time ICG enables a better identification of the biliary tree and thus increases surgical safety. The outcomes of laparoscopic cholecystectomy with and without ICG were compared using the duration of surgery, the rate of bile duct injury, the rate of conversion, complications and the length of stay.

Results

Seventy patients including 29 with and 41 without ICG underwent laparoscopic cholecystectomy within the period of investigation. The median duration of surgery was 53.0 vs. 54.0 min while the median length of stay was 2.0 d in the group with and without ICG respectively. The rate of conversion was 2.4% in the group without ICG, while no conversion was performed in the group with ICG. NO bile duct injury occurred in both groups. These differences were not statistically significant.

Conclusion

Laparoscopic cholecystectomy with real-time indocyanine green fluorescence cholangiography enables a better visualization and identification of biliary tree and therefore should be considered as a means of increasing the safety of laparoscopic cholecystectomy.

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

In recent years, the use of fluorescence-guided surgery (FGS) to treat benign and malignant visceral, hepatobiliary and pancreatic neoplasms has significantly increased. FGS relies on the fluorescence signal emitted by injected substances (fluorophores) after being illuminated by ad hoc laser sources to help guide the surgical procedure and provide the surgeon with real-time visualization of the fluorescent structures of interest that would be otherwise invisible. This review surveys and discusses the most common and emerging clinical applications of indocyanine green (ICG)-based fluorescence in visceral, hepatobiliary and pancreatic surgery. The analysis, findings, and discussion presented here rely on the authors' significant experience with this technique in their medical institutions, an up-to-date review of the most relevant articles published on this topic between 2014 and 2018, and lengthy discussions with key opinion leaders in the field during recent conferences and congresses. For each application, the benefits and limitations of this technique, as well as applicable future directions, are described. The imaging of fluorescence emitted by ICG is a simple, fast, relatively inexpensive, and harmless tool with numerous different applications in surgery for both neoplasms and benign pathologies of the visceral and hepatobiliary systems. The ever-increasing availability of visual systems that can utilize this tool will transform some of these applications into the standard of care in the near future. Further studies are needed to evaluate the strengths and weaknesses of each application of ICG-based fluorescence imaging in abdominal surgery.

Near-infrared fluorescent cholangiography - real-time visualization of the biliary tree during elective laparoscopic cholecystectomy

BACKGROUND

The purpose was to evaluate the efficacy of near-infrared fluorescent cholangiography (FC) in real-time visualization of the biliary tree during elective laparoscopic cholecystectomy.

METHODS

Fifty consecutive elective laparoscopic cholecystectomies were performed with fluorescent cholangiography. FC was performed at three time points: following exposure of Calot's triangle, prior to any dissection; and after partial and complete dissection of Calot's triangle.

RESULTS

The cystic duct (CD) was identified successfully by FC in 43 of 50 patients (86%) and in 45 of 50 patients (90%) before and after Calot's dissection respectively (p > 0.05). The common hepatic duct (CHD) and the common bile duct (CBD) were identified successfully in 12 of 50 patients (24%) and in 33 of 50 patients (66%) before Calot's dissection respectively and in 26 of 50 patients (52%) and in 47 of 50 patients (94%) after complete Calot's dissection (p = 0.007 and p = 0.001, respectively). Significant differences were observed for CBD visualization rate, in relation to BMI after Calot's dissection (p < 0.05) and history of cholecystitis, before Calot's dissection (p = 0.017). No bile duct injuries were reported.

CONCLUSION

Fluorescent cholangiography can be considered as a useful tool for intra-operative visualization of the biliary tree during laparoscopic cholecystectomies.

Optimizing the image of fluorescence cholangiography using ICG: a systematic review and ex vivo experiments

Background

Though often only briefly described in the literature, there are clearly factors that have an influence on the fluorescence intensity, and thereby the usefulness of the technique. This article aims to provide an overview of the factors influencing the fluorescence intensity of fluorescence imaging with Indocyanine green, primarily focussed on NIRF guided cholangiography.

Methods

A systematic search was conducted to gain an overview of currently used methods in NIRF imaging in laparoscopic cholecystectomies. Relevant literature was searched to gain advice on what methods to use. Ex vivo experiments were performed to assess various factors that influence fluorescence intensity and whether the found clinical advices can be confirmed.

Results

ICG is currently the most widely applied fluorescent dye. Optimal ICG concentration lies between 0.00195 and 0.025 mg/ml, and this dose should be given as early as achievable—but maximum 24 h—before surgery. When holding the laparoscope closer and perpendicular to the dye, the signal is most intense. In patients with a higher BMI and/or cholecystitis, fluorescence intensity is lower, but NIRF seems to be more helpful. There are differences between various marketed fluorescence systems. Also, no uniform method to assess fluorescence intensity is available yet.

Conclusions

This study identified and discussed several factors that influence the signal of fluorescence cholangiography. These factors should be taken into account when using NIRF cholangiography. Also, surgeons should be aware of new dyes and clinical systems, in order to benefit most from the potential of NIRF imaging.

Electronic supplementary material

The online version of this article (10.1007/s00464-018-6233-x) contains supplementary material, which is available to authorized users.

The emerging role for robotics in cholecystectomy: the dawn of a new era?

Though laparoscopic cholecystectomy (LC) was highly criticized in its early stages, it quickly grew to become a new standard of care and has revolutionized the field of general surgery. Now emerging robotic technology is making its way into the minimally invasive arena. Robotic cholecystectomy (RC) is often disparaged as a costly technology that can lead to increased operative times with outcomes that are quite similar to LC. However, this perspective is skewed as many existing studies were performed in the early phase of learning for this procedure. RC can be performed in a cost-effective manner as the volume of robotic procedures increases. In addition, improved visualization and capability to perform fluorescence cholangiography can improve the safety profile of cholecystectomy to a level that has not yet been achieved with conventional laparoscopy. Advanced simulation technology for robotic surgery, and newer single-site robotic platforms have the potential to further revolutionize this technology and lead to improved patient satisfaction. In this review, we will present current data, trends, and controversies in robotic-assisted cholecystectomy.

A Technique to Define Extrahepatic Biliary Anatomy Using Robotic Near-Infrared Fluorescent Cholangiography

BACKGROUND

Bile duct injury is a rare but serious complication of minimally invasive cholecystectomy. Traditionally, intraoperative cholangiogram has been used in difficult cases to help delineate anatomical structures, however, new imaging modalities are currently available to aid in the identification of extrahepatic biliary anatomy, including near-infrared fluorescent cholangiography (NIFC) using indocyanine green (ICG).1-5 The objective of the study was to evaluate if this technique may aid in safe dissection to obtain the critical view.

METHODS

Thirty-five consecutive multiport robotic cholecystectomies using NIFC with ICG were performed using the da Vinci Firefly Fluorescence Imaging System. All patients received 2.5 mg ICG intravenously at the time of intubation, followed by patient positioning, draping, and establishment of pneumoperitoneum. No structures were divided until the critical view of safety was achieved. Real-time toggling between NIFC and bright-light illumination was utilized throughout the case to define the extrahepatic biliary anatomy.

RESULTS

ICG was successfully administered to all patients without complication, and in all cases the extrahepatic biliary anatomy was able to be identified in real-time 3D. All procedures were completed without biliary injury, conversion to an open procedure, or need for traditional cholangiography to obtain the critical view. Specific examples of cases where x-ray cholangiography or conversion to open was avoided and NIFC aided in safe dissection leading to the critical view are demonstrated, including (1) evaluation for aberrant biliary anatomy, (2) confirmation of non-biliary structures, and (3) use in cases where the infundibulum is fused to the common bile duct.

CONCLUSION

NIFC using ICG is demonstrated as a useful technique to rapidly identify and aid in the visualization of extrahepatic biliary anatomy. Techniques that selectively utilize this technology specifically in difficult cases where the anatomy is unclear are demonstrated in order to obtain the critical view of safety.

A new fluorescence imaging technique for visualizing hepatobiliary structures using sodium fluorescein: result of a preclinical study in a rat model

BACKGROUND

Near-infrared fluorescence imaging has been recently applied in the field of hepatobiliary surgery. Our objective was to apply blue light fluorescence imaging to cholangiography and liver mapping during laparoscopic surgery. Therefore, we designed a preclinical study to evaluate the feasibility of using blue light fluorescence for cholangiography and liver mapping in a rat model.

METHODS

Sodium fluorescein solution (1 mL to each individual) were administered intravenously to 20 male Sprague-Dawley rats (6 weeks old, 200-250 g), after laparotomy. Whole abdominal organs were observed under blue light (at a wavelength of 440-490 nm) emitted from a commercialized LED curing light.

RESULTS

Immediately after the tracer solution was administered into the circulatory system of the rat, it was possible to visualize the location of the kidneys and the bile duct under blue light emitted from the light source. The liver was vaguely stained green by the tracer, while the ureters were not. After establishing biliary retention via duct clamping in the left lateral segment of the liver, the green color of the segment became distinct by the tracer, which showed vague coloration following release of the clamp.

CONCLUSION

We established the preclinical basis for using blue light fluorescence cholangiography and liver mapping in this study. The clinical feasibility of these techniques during laparoscopic cholecystectomy and hepatectomy remained to be demonstrated.

Prospective Evaluation of Precision Multimodal Gallbladder Surgery Navigation: Virtual Reality, Near-infrared Fluorescence, and X-ray-based Intraoperative Cholangiography

OBJECTIVE

We aimed to prospectively evaluate NIR-C, VR-AR, and x-ray intraoperative cholangiography (IOC) during robotic cholecystectomy.

BACKGROUND

Near-infrared cholangiography (NIR-C) provides real-time, radiation-free biliary anatomy enhancement. Three-dimensional virtual reality (VR) biliary anatomy models can be obtained via software manipulation of magnetic resonance cholangiopancreatography, enabling preoperative VR exploration, and intraoperative augmented reality (AR) navigation.

METHODS

Fifty-eight patients were scheduled for cholecystectomy for gallbladder lithiasis. VR surgical planning was performed on virtual models. At anesthesia induction, indocyanine green was injected intravenously. AR navigation was obtained by overlaying the virtual model onto real-time images. Before and after Calot triangle dissection, NIR-C was obtained by turning the camera to NIR mode. Finally, an IOC was performed. The 3 modality performances were evaluated and image quality was assessed with a Likert-scale questionnaire.

RESULTS

The three-dimensional VR planning enabled the identification of 12 anatomical variants in 8 patients, of which only 7 were correctly reported by the radiologists (P = 0.037). A dangerous variant identified at VR induced a "fundus first" approach. The cystic-common bile duct junction was visualized before Calot triangle dissection at VR in 100% of cases, at NIR-C in 98.15%, and in 96.15% at IOC.Mean time to obtain relevant images was shorter with NIR-C versus AR (P = 0.008) and versus IOC (P = 0.00000003). Image quality scores were lower with NIR-C versus AR (P = 0.018) and versus IOC (P < 0.0001).

CONCLUSIONS

This high-tech protocol illustrates the multimodal imaging of biliary anatomy towards precision cholecystectomy. Those visualization techniques could complement to reduce the likelihood of biliary injuries (NCT01881399).

Near-infrared cholecystocholangiography with direct intragallbladder indocyanine green injection: preliminary clinical results

BACKGROUND

Near-infrared (NIR) fluorescence cholangiography by systemic administration of indocyanine green (ICG) enhances the visualization of the biliary tree anatomy. However, the simultaneous enhancement of liver parenchyma can disturb the visualization of critical details. We herein proposed a new technique of NIR cholecystocholangiography by intragallbladder ICG injection to increase the safety during laparoscopic cholecystectomy.

METHODS

A total of 46 patients scheduled for laparoscopic cholecystectomy for symptomatic lithiasis (n = 21) or cholecystitis (n = 25) were enrolled. A fluorescence cholangiography by direct gallbladder injection of ICG was performed in all cases. Of them, the ICG was injected through a previously placed percutaneous transhepatic gallbladder drainage catheter (n = 18) or by intraoperative, percutaneous needle puncture of the gallbladder (n = 28). Visualization of biliary structures, including the cystic duct (CD), the common bile and hepatic ducts (CBD and CHD), the gallbladder neck, and the Hartmann's pouch (HP), was performed using White Light (served as control modality) and by NIR enhancement.

RESULTS

Cholecystocholangiography provided a significantly higher rate of visualization of the CD in case of cholecystitis with mild adhesions, and an improved visualization of the HP, CBD, and CHD in case of severe inflammation, when compared to White Light observation. There were no benefits of NIR in case of non-inflamed lithiasis.

CONCLUSIONS

Clinical translation of NIR cholecystocholangiography has been successful with a noise-free visualization of biliary anatomy. It can be considered in difficult cases to increase the safety of laparoscopic cholecystectomy.

Direct Gallbladder Indocyanine Green Injection Fluorescence Cholangiography During Laparoscopic Cholecystectomy

BACKGROUND

Intravenous injection of indocyanine green (ICG) is used to illuminate extrahepatic biliary anatomy. Fluorescence of biliary structures may lower surgical complications that can arise due to inadvertent injury to the common bile duct. We describe a method of injecting ICG directly into the gallbladder to define the cystic duct and common bile duct anatomy.

MATERIALS AND METHODS

A standard laparoscopic cholecystectomy was performed using a laparoscope with near-infrared imaging capability. Before dissection, the gallbladder was punctured with a cholangiogram catheter or a pigtail catheter to aspirate the bile within the gallbladder. The aspirated bile is mixed with ICG solution, which is reinjected into the gallbladder to fluoresce the gallbladder, cystic duct, and common bile duct structures.

RESULTS

Eleven patients underwent direct gallbladder ICG injection for fluorescence cholangiography during cholecystectomy. Direct gallbladder ICG injection clearly defined the extrahepatic biliary anatomy, including the cystic duct-common bile duct junction, by fluorescence. In addition, the dissection plane between the gallbladder and the liver is highlighted with the gallbladder ICG fluorescence.

CONCLUSIONS

Direct gallbladder ICG injection provides immediate visualization of extrahepatic biliary structures and clarifies the dissection plane between the gallbladder and the liver bed.

Cystic duct variation detected by near-infrared fluorescent cholangiography during laparoscopic cholecystectomy

Near-infrared fluorescent cholangiography (NIRFC) is an emerging technique for easy intraoperative recognition of biliary anatomy. We present a case of cystic duct variation detected by NIRFC which had a potential risk for biliary injury if not detected. A 32-year-old female was admitted to the Seoul St. Mary's Hospital for surgery for an incidental gallbladder polyp. We performed laparoscopic cholecystectomy with NIRFC. In fluorescence mode, a long cystic duct and an accessory short hepatic duct joining to the cystic duct were found and the operation was completed safely. The patient recovered successfully. NIRFC is expected to be a promising procedure that will help minimize biliary injury during laparoscopic cholecystectomy.

Indocyanine green-enhanced fluorescence for assessing parathyroid perfusion during thyroidectomy

Identification of the parathyroid glands during thyroid surgery may prevent their inadvertent surgical removal and thus provide a better postoperative quality of life. Nevertheless, the most common "technique" for intraoperative evaluation of perfusion of parathyroid gland tissues during thyroid surgery is visual inspection of the physical condition of tissues, e.g., their color and bleeding edges. Another technique is measurement of intact parathyroid hormone. Recently, indocyanine green-enhanced fluorescence has been used in various surgical techniques, particularly laparoscopic surgery, to improve visualization and to provide detailed anatomical information. Fluorescent optical guidance helps surgeons to avoid inadvertent tissue injury while enhancing procedural efficiency. This technique has potential use for evaluating perfusion of the parathyroid gland in real-time intraoperative angiography.