Intraoperative near-infrared fluorescent cholangiography (NIRFC) in mouse models of bile duct injury

Is the use of a routine intraoperative cholangiogram necessary in laparoscopic cholecystectomy?

INTRODUCTION

Although laparoscopic cholecystectomy (LC) has been standard of care for symptomatic gallstone disease for almost 30 years, the use of routine intraoperative cholangiogram (IOC) remains controversial. There are marked variations in the use IOC during LC internationally. Debate has continued about its benefit, in part because of inconsistent benefit, time, and resources required to complete IOC. This literature review is presented as a debate to outline the arguments in favour of and against routine IOC in laparoscopic cholecystectomy.

METHODS

A standard literature review of PubMed, Medline, OVID, EMBASE, CINHIL and Web of Science was performed, specifically for literature pertaining to the use of IOC or alternative intra-operative methods for imaging the biliary tree in LC. Two authors assembled the evidence in favour, and two authors assembled the evidence against.

RESULTS

From this controversies piece we found that there is little discernible change in the number of BDIs requiring repair procedures. Although IOC is associated with a small absolute reduction in bile duct injury, there are other confounding factors, including a change in laparoscopic learning curves. Alternative technologies such as intra-operative ultrasound, indocyanine green imaging, and increased access to ERCP may contribute to a reduction in the need for routine IOC.

CONCLUSIONS

In spite of 30 years of accumulating evidence, routine IOC remains controversial. As technology advances, it is likely that alternative methods of imaging and accessing the bile duct will supplant routine IOC.

Intraoperative support with three-dimensional holographic cholangiography in hepatobiliary surgery

PURPOSE

This study was performed to investigate the potential of intraoperative three-dimensional (3D) holographic cholangiography, which provides a computer graphics model of the biliary tract, with mixed reality techniques.

METHODS

Two patients with intraductal papillary neoplasm of the bile duct were enrolled in the study. Intraoperative 3D cholangiography was performed in a hybrid operating room. Three-dimensional polygon data using the acquired cholangiography data were installed into a head mount display (HoloLens; Microsoft Corporation, Redmond, WA, USA).

RESULTS

Upon completion of intraoperative 3D cholangiography, a hologram was immediately and successfully made in the operating room using the acquired cholangiography data, and several surgeons wearing the HoloLens succeeded in sharing the same hologram. Compared with usual two-dimensional cholangiography, this 3D holographic cholangiography technique contributed to more accurate reappearance of the bile ducts, especially the B1 origination site, and moving the hologram from the respective operators' angles by means of easy gesture-handling without any monitors.

CONCLUSION

Intraoperative 3D holographic cholangiography might be a new next-generation operation-support tool in terms of immediacy, accurate anatomical reappearance, and ease of handling.

Laparoscopic cholecystectomy in a swine model using a novel near-infrared fluorescent IV dye (BL-760)

BACKGROUND AND OBJECTIVES

Bile duct injury during laparoscopic cholecystectomy has an incidence rate of 1%-2% and commonly appears under conditions of severe inflammation, adhesion, or unexpected anatomical variations. Despite the difficulties and rising concerns of identifying bile duct during surgeries, surgeons do not have a specific modality to identify bile duct except intraoperative cholangiography. While no biliary-specific fluorescent dye exists for clinical use, our team has previously described the development of a preclinical biliary-specific dye, BL-760. Here, we present our study of laparoscopic cholecystectomy using the fluorescent dye in a swine model.

STUDY DESIGN/MATERIALS AND METHODS

With an approval from Institutional Animal Care and Use Committee, two 20-25 kg swine underwent laparoscopic abdominal surgery using a Food and Drug Administration-cleared fluorescent laparoscopic system. Images of the liver and gallbladder were taken both before and after intravenous injection of the novel fluorescent dye. The dye was dosed at 60 μg/kg and injected via the ear vein. The amount of time taken to visualize fluorescence in the biliary tract was measured. Fluorescent signal was observed after injection, and target-to-background ratio (TBR) of the biliary tract to surrounding cystic artery and liver parenchyma was measured.

RESULTS

Biliary tract visualization under fluorescent laparoscopy was achieved within 5 min after the dye injection without any adverse effects. Cystic duct and extrahepatic duct were clearly visualized and identified with TBR values of 2.19 and 2.32, respectively, whereas no fluorescent signal was detected in liver. Cystic duct and artery were successfully ligated by an endoscopic clip applier with the visual assistance of highlighted biliary tract images. Laparoscopic cholecystectomy was completed within 30 min in each case without any complications.

CONCLUSIONS

BL-760 is a novel preclinical fluorescent dye useful for intraoperative identification and visualization of biliary tract. Such fluorescent dye that is exclusively metabolized by liver and rapidly excreted into biliary tract would be beneficial for all types of hepato-biliary surgeries. With the validation of additional preclinical data, this novel dye has potential to be a valuable tool to prevent any iatrogenic biliary injuries and/or bile leaks during laparoscopic abdominal and liver surgeries.

Consensus Guidelines for the Use of Fluorescence Imaging in Hepatobiliary Surgery

OBJECTIVE

To establish consensus recommendations for the use of fluorescence imaging with indocyanine green (ICG) in hepatobiliary surgery.

BACKGROUND

ICG fluorescence imaging has gained popularity in hepatobiliary surgery in recent years. However, there is varied evidence on the use, dosage, and timing of administration of ICG in clinical practice. To standardize the use of this imaging modality in hepatobiliary surgery, a panel of pioneering experts from the Asia-Pacific region sought to establish a set of consensus recommendations by consolidating the available evidence and clinical experiences.

METHODS

A total of 13 surgeons experienced in hepatobiliary surgery and/or minimally invasive surgery formed an expert consensus panel in Shanghai, China in October 2018. By the modified Delphi method, they presented the relevant evidence, discussed clinical experiences, and derived consensus statements on the use of ICG in hepatobiliary surgery. Each statement was discussed and modified until a unanimous consensus was achieved.

RESULTS

A total of 7 recommendations for the clinical applications of ICG in hepatobiliary surgery were formulated.

CONCLUSIONS

The Shanghai consensus recommendations offer practical tips and techniques to augment the safety and technical feasibility of ICG fluorescence-guided hepatobiliary surgery, including laparoscopic cholecystectomy, liver segmentectomy, and liver transplantation.

The Efficacy of Intraoperative Fluorescent Imaging Using Indocyanine Green for Cholangiography During Cholecystectomy and Hepatectomy

PURPOSE

Bile duct injury is one of the most serious complications of laparoscopic cholecystectomy. Intraoperative indocyanine green (ICG) cholangiography is a safe and useful navigation modality for confirming the biliary anatomy. ICG cholangiography is expected to be a routine method for helping avoid bile duct injuries.

PATIENTS AND METHODS

We examined 25 patients who underwent intraoperative cholangiography using ICG fluorescence. Two methods of ICG injection are used: intrabiliary injection (percutaneous transhepatic gallbladder drainage [PTGBD], gallbladder [GB] puncture and endoscopic nasobiliary drainage [ENBD]) at a dosage of 0.025 mg during the operation or intravenous injection with 2.5 mg ICG preoperatively.

RESULTS

There were 24 patients who underwent laparoscopic cholecystectomy and 1 patient who underwent hepatectomy. For laparoscopic cholecystectomy, the average operation time was 127 (50-197) minutes, and estimated blood loss was 43.2 (0-400) g. The ICG administration route was intravenous injections in 12 cases and intrabiliary injection in 12 cases (GB injection: 3 cases, PTGBD: 8 cases, ENBD:1 case). The course of the biliary tree was able to be confirmed in all cases that received direct injection into the biliary tract, whereas bile structures were recognizable in only 10 cases (83.3%) with intravenous injection. The postoperative hospital stay was 4.6 (3-9) days, and no postoperative complications (Clavien-Dindo ≧IIIa) were observed. For hepatectomy, a tumor located near the left Glissonian pedicle was resected using a fluorescence image guide. Biliary structures were fluorescent without injury after resecting the tumor. No adverse events due to ICG administration were observed, and the procedure was able to be performed safely.

CONCLUSION

ICG fluorescence imaging allows surgeons to visualize the course of the biliary tree in real time during cholecystectomy and hepatectomy. This is considered essential for hepatobiliary surgery to prevent biliary tree injury and ensure safe surgery.

Randomized Trial of Near-infrared Incisionless Fluorescent Cholangiography

BACKGROUND

Incisionless near-infrared fluorescent cholangiography (NIFC) is emerging as a promising tool to enhance the visualization of extrahepatic biliary structures during laparoscopic cholecystectomies.

METHODS

We conducted a single-blind, randomized, 2-arm trial comparing the efficacy of NIFC (n = 321) versus white light (WL) alone (n = 318) during laparoscopic cholecystectomy. Using the KARL STORZ Image1 S imaging system with OPAL1 technology for NIR/ICG imaging, we evaluated the detection rate for 7 biliary structures-cystic duct (CD), right hepatic duct (RHD), common hepatic duct, common bile duct, cystic common bile duct junction, cystic gallbladder junction (CGJ), and accessory ducts -before and after surgical dissection. Secondary calculations included multivariable analysis for predictors of structure visualization and comparing intergroup biliary duct injury rates.

RESULTS

Predissection detection rates were significantly superior in the NIFC group for all 7 biliary structures, ranging from 9.1% versus 2.9% to 66.6% versus 36.6% for the RHD and CD, respectively, with odds ratios ranging from 2.3 (95% CI 1.6-3.2) for the CGJ to 3.6 (1.6-9.3) for the RHD. After dissection, similar intergroup differences were observed for all structures except CD and CGJ, for which no differences were observed. Significant odds ratios ranged from 2.4 (1.7-3.5) for the common hepatic duct to 3.3 (1.3-10.4) for accessory ducts. Increased body mass index was associated with reduced detection of most structures in both groups, especially before dissection. Only 2 patients, both in the WL group, sustained a biliary duct injury.

CONCLUSIONS

In a randomized controlled trial, NIFC was statistically superior to WL alone visualizing extrahepatic biliary structures during laparoscopic cholecystectomy.

REGISTRATION NUMBER

NCT02702843.

Effectiveness and safety of indocyanine green fluorescence imaging-guided hepatectomy for liver tumors: A systematic review and first meta-analysis

BACKGROUND

This meta-analysis was conducted to evaluate the effectiveness and safety of indocyanine green fluorescence imaging-guided hepatectomy(FIGH) for liver tumors.

METHODS

Clinical studies were retrieved from the PubMed, Embase, Cochrane Library, Medline and Web of Science electronic databases. Primary outcomes included operative time, blood loss, blood transfusion, hospital stay, R0 resection, postoperative complications, postoperative mortality and 1-year recurrence rate. Study-specific effect sizes and their 95% confidence intervals (CIs) were combined to calculate the pooled value using a fixed-effects or random-effects model.

RESULTS

Six studies comprising 587 patients were included. Major operative time (mean difference [MD] = -55.45; 95% CI = -78.85- -32.05), blood loss (MD = 12.99; 95% CI = 12.00-13.97), hospital stay (rate difference [RD] = -12.61; 95% CI = -15.06- -10.17), and postoperative complications (RD = -0.07; 95% CI = -0.12- -0.01) were all less in the FIGH group than in the traditional hepatectomy(TH) group. No differences were found in blood transfusion, R0 resection or 1-year recurrence rate. No perioperative mortality was observed in either group.

CONCLUSION

Based on current evidence, applying indocyanine green fluorescence imaging technology to accurately diagnose and treat liver tumors can effectively reduce operative time, blood loss, hospital stay and postoperative complications.

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.

A Biliary Tract-Specific Near-Infrared Fluorescent Dye for Image-Guided Hepatobiliary Surgery

Despite advances, visual inspection, palpation, and intraoperative ultrasound remain the most utilized tools during surgery today. A particularly challenging issue is the identification of the biliary system due to its complex architecture partially embedded within the liver. Fluorescence guided surgical interventions, particularly using near-infrared (NIR) wavelengths, are an emerging approach for the real-time assessment of the hepatobiliary system. However, existing fluorophores, such as the FDA-approved indocyanine green (ICG), have significant limitations for rapid and selective visualization of bile duct anatomy. Here we report a novel NIR fluorophore, BL (Bile Label)-760, which is exclusively metabolized by the liver providing high signal in the biliary system shortly after intravenous administration. This molecule was identified by first screening a small set of known heptamethine cyanines including clinically utilized agents. After finding that none of these were well-suited, we then designed and tested a small series of novel dyes within a prescribed polarity range. We validated the molecule that emerged from these efforts, BL-760, through animal studies using both rodent and swine models employing a clinically applicable imaging system. In contrast to ICG, BL-760 fluorescence revealed a high target-to-background ratio (TBR) of the cystic duct relative to liver parenchyma 5 min after intravenous injection. During hepatic resection surgery, intrahepatic ducts were clearly highlighted, and bile leakage was easily detected. In conclusion, BL-760 has highly promising properties for intraoperative navigation during hepatobiliary surgery.

Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond

The sick preterm infant monitoring is an intriguing job that medical staff in Neonatal Intensive Care Units (NICU) must deal with on a daily basis. As a standards monitoring procedure, preterm infants are monitored via sensors and electrodes that are firmly attached to their fragile and delicate skin and connected to processing monitors. However, an alternative exists in contactless imaging to record such physiological signals (we call it as Physio-Markers), detecting superficial changes and internal structures activities which can be used independently of, or aligned with, conventional monitors. Countless advantages can be gained from unobtrusive monitoring not limited to: (1) quick data generation; (2) decreasing physical and direct contact with skin, which reduces skin breakdown and minimizes risk of infection; and (3) reduction of electrodes and probes connected to clinical monitors and attached to the skin, which allows greater body surface-area for better care. This review is an attempt to build a solid ground for and to provide a clear perspective of the potential clinical applications of technologies inside NICUs that use contactless imaging modalities such as Visible Light Imaging (VLI), Near Infrared Spectroscopy (NIRS), and Infrared Thermography (IRT).

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.

Real-time, label-free, intraoperative visualization of peripheral nerves and micro-vasculatures using multimodal optical imaging techniques

Accurate, real-time identification and display of critical anatomic structures, such as the nerve and vasculature structures, are critical for reducing complications and improving surgical outcomes. Human vision is frequently limited in clearly distinguishing and contrasting these structures. We present a novel imaging system, which enables noninvasive visualization of critical anatomic structures during surgical dissection. Peripheral nerves are visualized by a snapshot polarimetry that calculates the anisotropic optical properties. Vascular structures, both venous and arterial, are identified and monitored in real-time using a near-infrared laser-speckle-contrast imaging. We evaluate the system by performing in vivo animal studies with qualitative comparison by contrast-agent-aided fluorescence imaging.

Nanoparticle as a novel tool in hyperthermic intraperitoneal and pressurized intraperitoneal aerosol chemotheprapy to treat patients with peritoneal carcinomatosis

The treatment of peritoneal surface malignances has changed considerably over the last thirty years. Unfortunately, the palliative is the only current treatment for peritoneal carcinomatosis (PC). Two primary intraperitoneal chemotherapeutic methods are used. The first is combination of cytoreductive surgery (CRS) and Hyperthermic IntraPEritoneal Chemotherapy (HIPEC), which has become the gold standard for many cases of PC. The second is Pressurized IntraPeritoneal Aerosol Chemotheprapy (PIPAC), which is promising direction to minimally invasive as safedrug delivery. These methods were improved through multicenter studies and clinical trials that yield important insights and solutions. Major method development has been made through nanomedicine, specifically nanoparticles. Here, we are presenting the latest advances of nanoparticles and their application to precision diagnostics and improved treatment strategies for PC. These advances will likely develop both HIPEC and PIPAC methods that used for in vitro and in vivo studies. Several benefits of using nanoparticles will be discussed including: 1) Nanoparticles as drug delivery systems; 2) Nanoparticles and Near Infrred (NIR) Irradiation; 3) use of nanoparticles in perioperative diagnostic and individualized treatment planning; 4) use of nanoparticles as anticancer dressing's, hydrogels and as active beeds for optimal reccurence prevention; and 5) finally the curent in vitro and in vivo studies and clinical trials of nanoparticles. The current review highlighted use of nanoparticles as novel tools in improving drug delivery to be effective for treatment patients with peritoneal carcinomatosis.

Biliary System Architecture: Experimental Models and Visualization Techniques

The complex architecture of the liver biliary network represents a structural prerequisite for the formation and secretion of bile as well as excretion of toxic substances through bile ducts. Disorders of the biliary tract affect a significant portion of the worldwide population, often leading to cholestatic liver diseases. Cholestatic liver disease is a condition that results from an impairment of bile formation or bile flow to the gallbladder and duodenum. Cholestasis leads to dramatic changes in biliary tree architecture, worsening liver disease and systemic illness. Recent studies show that the prevalence of cholestatic liver diseases is increasing. The availability of well characterized animal models, as well as development of visualization approaches constitutes a critical asset to develop novel pathogenetic concepts and new treatment strategies.

Mechanism of dynamic near-infrared fluorescence cholangiography of extrahepatic bile ducts and applications in detecting bile duct injuries using indocyanine green in animal models

Fluorescence intraoperative cholangiography (IOC) is a potential alternative for identifying anatomical variation and preventing iatrogenic bile duct injuries by using the near-infrared probe indocyanine green (ICG). However, the dynamic process and mechanism of fluorescence IOC have not been elucidated in previous publications. Herein, the optical properties of the complex of ICG and bile, dynamic fluorescence cholangiography and iatrogenic bile duct injuries were investigated. The emission spectrum of ICG in bile peaked at 844 nm and ICG had higher tissue penetration. Extrahepatic bile ducts could fluoresce 2 min after intravenous injection, and the fluorescence intensity reached a peak at 8 min. In addition, biliary dynamics were observed owing to ICG excretion from the bile ducts into the duodenum. Quantitative analysis indicated that ICG-guided fluorescence IOC possessed a high signal to noise ratio compared to the surrounding peripheral tissue and the portal vein. Fluorescence IOC was based on rapid uptake of circulating ICG in plasma by hepatic cells, excretion of ICG into the bile and then its interaction with protein molecules in the bile. Moreover, fluorescence IOC was sensitive to detect bile duct ligation and acute bile duct perforation using ICG in rat models. All of the results indicated that fluorescence IOC using ICG is a valid alternative for the cholangiography of extrahepatic bile ducts and has potential for measurement of biliary dynamics.

Near-infrared fluorescence cholangiography assisted laparoscopic cholecystectomy versus conventional laparoscopic cholecystectomy (FALCON trial): study protocol for a multicentre randomised controlled trial

INTRODUCTION

Misidentification of the extrahepatic bile duct anatomy during laparoscopic cholecystectomy (LC) is the main cause of bile duct injury. Easier intraoperative recognition of the biliary anatomy may be accomplished by using near-infrared fluorescence (NIRF) imaging after an intravenous injection of indocyanine green (ICG). Promising results were reported for successful intraoperative identification of the extrahepatic bile ducts compared to conventional laparoscopic imaging. However, routine use of ICG fluorescence laparoscopy has not gained wide clinical acceptance yet due to a lack of high-quality clinical data. Therefore, this multicentre randomised clinical study was designed to assess the potential added value of the NIRF imaging technique during LC.

METHODS AND ANALYSIS

A multicentre, randomised controlled clinical trial will be carried out to assess the use of NIRF imaging in LC. In total, 308 patients scheduled for an elective LC will be included. These patients will be randomised into a NIRF imaging laparoscopic cholecystectomy (NIRF-LC) group and a conventional laparoscopic cholecystectomy (CLC) group. The primary end point is time to 'critical view of safety' (CVS). Secondary end points are 'time to identification of the cystic duct (CD), of the common bile duct, the transition of CD in the gallbladder and the transition of the cystic artery in the gallbladder, these all during dissection of CVS'; 'total surgical time'; 'intraoperative bile leakage from the gallbladder or cystic duct'; 'bile duct injury'; 'postoperative length of stay', 'complications due to the injected ICG'; 'conversion to open cholecystectomy'; 'postoperative complications (until 90 days postoperatively)' and 'cost-minimisation'.

ETHICS AND DISSEMINATION

The protocol has been approved by the Medical Ethical Committee of Maastricht University Medical Center/Maastricht University; the trial has been registered at ClinicalTrials.gov. The findings of this study will be disseminated widely through peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT02558556.

Anatomy of the Murine Hepatobiliary System: A Whole-Organ-Level Analysis Using a Transparency Method

The biliary tract is a well-branched ductal structure that exhibits great variation in morphology among vertebrates. Its function is maintained by complex constructions of blood vessels, nerves, and smooth muscles, the so-called hepatobiliary system. Although the mouse (Mus musculus) has been used as a model organism for humans, the morphology of its hepatobiliary system has not been well documented at the topographical level, mostly because of its small size and complexity. To reconcile this, we conducted whole-mount anatomical descriptions of the murine extrahepatic biliary tracts with related blood vessels, nerves, and smooth muscles using a recently developed transparentizing method, CUBIC. Several major differences from humans were found in mice: (1) among the biliary arteries, the arteria gastrica sinistra accessoria was commonly found, which rarely appears in humans; (2) the sphincter muscle in the choledochoduodenal junction is unseparated from the duodenal muscle; (3) the pancreatic duct opens to the bile duct without any sphincter muscles because of its distance from the duodenum. This state is identical to a human congenital malformation, an anomalous arrangement of pancreaticobiliary ducts. However, other parts of the murine hepatobiliary system (such as the branching patterns of the biliary tract, blood vessels, and nerves) presented the same patterns as humans and other mammals topologically. Thus, the mouse is useful as an experimental model for studying the human hepatobiliary system.

Visualizing biliary tracts with isosulphan blue to prevent injury during laparoscopic cholecystectomy: a preliminary cadaveric study

BACKGROUND

Bile duct injury (BDI) as a complication of laparoscopic cholecystectomy may result in biliary cirrhosis with a high morbidity-mortality rate. Recurrent invasive procedures may be required for the optimum management. The most frequent causative factor in BDI is anatomical misidentification, particularly by inexperienced surgeons. Direct coloration of the cystic duct, bile duct, and gallbladder may decrease biliary tract injury.

METHODS

This study was conducted during 10 standard, fresh cadaver autopsies at the Council of Forensic Medicine, Istanbul. Following needle puncture of the gallbladder fundus and aspiration of the bile content, identical quantities of isosulphan blue were injected into the gallbladder to visualize the biliary tract.

RESULTS

Of the ten fresh cadavers, three were males and seven were females; the mean age at death was 43 years (range 22-76 years). Successful visualization of the colored biliary tract, encompassing the gallbladder, cystic duct, and bile duct, was achieved in all of the cadavers.

CONCLUSIONS

Visualization of the biliary tract may reduce the risk associated with dissection of Calot's triangle. Surgical BDI risk following anatomical misidentification could be reduced by intraoperative injection of isosulphan blue; further studies are required to validate the clinical utility of this technique.

Extraparenchymal Bile/Pancreatic Ducts and Duodenal Papillae: Pathologic Evaluation in Nonclinical Species--A Brief Review

This review focuses on the anatomy, histologic preparation, and pathologic evaluation of extraparenchymal bile and pancreatic ducts (BPDs) and their openings at the duodenal papillae in the cynomolgus macaque (Macaca fascicularis), the Beagle dog (Canis familiaris), the Wistar Hanover rat (Rattus norvegicus), and the CD1 mouse (Mus musculus). In nonclinical safety assessment, intraparenchymal BPDs (with sections of liver and pancreas, respectively) are evaluated routinely. However, detailed evaluation of the extraparenchymal BPDs or the duodenal papillae is not included. In the context of nonclinical safety assessment studies, this review describes situations in which evaluation of extraparenchymal ductal structures and duodenal papillae may be useful in characterizing test article-related changes; elucidates anatomic similarities between human, macaque, and dog and notable differences in rats and mice; and consolidates the information required for the histopathologic evaluation of these tissues.

Routine use of fluorescent incisionless cholangiography as a new imaging modality during laparoscopic cholecystectomy

BACKGROUND

Intraoperative incisionless fluorescent cholangiography (IOIFC) has been described to identify extrahepatic biliary anatomy. Potential advantages of the routine use of intraoperative incisionless fluorescent cholangiography were evaluated in a consecutive series of cases.

METHODS

A total of 45 patients undergoing laparoscopic cholecystectomy between January and July 2013 were consented and included in this study. We analyzed a prospectively collected database for feasibility, cost, time, usefulness, teaching tool, safety, learning curve, X-ray exposure, complexity, and real-time surgery of IOIFC. A single dose of 0.05 mg/kg of Indocyanine green was administered prior to surgery. During the procedure, a laparoscopic fluorescence system was used.

RESULTS

IOIFC could be performed in all 45 patients, whereas intraoperative cholangiography could be performed in 42 (93 %). Individual median cost of performing IOFC was cheaper than IOC (13.97 ± 4.3 vs 778.43 ± 0.4 USD) per patient, p = 0.0001). IOFC was faster than IOC (0.71 ± 0.26 vs 7.15 ± 3.76 minutes, p < 0.0001). The cystic duct was identified by IOFC in 44 out of 45 patients (97.77 %).

CONCLUSION

IOIFC appears to be a feasible, low-cost, expeditious, useful, and effective imaging modality when performing LC. It is safe, easy to perform and interpret, and does not require a learning curve or X-ray. It can be used for real time surgery to delineate the extrahepatic biliary structures.

Fluorescent imaging of the biliary tract during laparoscopic cholecystectomy

The introduction of laparoscopic cholecystectomy was associated with increased incidences of bile duct injury. The primary cause appears to be misidentification of the biliary anatomy. Routine intra-operative cholangiography has been recommended to reduce accidental duct injury, although in practice it is more often reserved for selected cases. There has been interest in the use of fluorescent agents excreted via the biliary system to enable real-time intra-operative imaging, to aid the laparoscopic surgeon in correctly interpreting the anatomy. The primary aim of this review is to evaluate the ability of fluorescent cholangiography to identify important biliary anatomy intra-operatively. Secondary aims are to investigate its ability to detect important intra-operative pathology such as bile leaks, identify potential alternative fluorophores, and evaluate the evidence regarding patient outcomes.

From shadow to light: visualization of extrahepatic bile ducts using image-enhanced laparoscopy

BACKGROUND

Correct recognition of the extrahepatic bile ducts is thought to be crucial to reduce the risk of bile duct injuries during various laparoscopic procedures. Image-enhanced laparoscopy techniques, utilizing various optical modalities other than white light, may help in detecting structures "hidden" underneath connective tissue.

METHODS

A systematic literature search was conducted of studies describing image-enhanced laparoscopy techniques for visualization of the extrahepatic bile ducts.

RESULTS

In all, 29 articles met inclusion criteria. They describe various techniques in the animal or human setting, including autofluorescence imaging, drug-enhanced fluorescence imaging, infrared thermography, and spectral imaging. This review describes these various techniques and their results.

CONCLUSION

Image-enhanced laparoscopy techniques for real-time visualization of extrahepatic bile ducts are still in its infancy. Out of the techniques currently described, indocyanine green-enhanced near-infrared fluorescence laparoscopy has the most mature results, but other techniques also appear promising. It can be expected that in the future, image-enhanced laparoscopy might become a routine adjunct to any white-light laparoscopic operation near the hepatic hilum.

Image-guided cancer surgery using near-infrared fluorescence

Paradigm shifts in surgery arise when surgeons are empowered to perform surgery faster, better and less expensively than current standards. Optical imaging that exploits invisible near-infrared (NIR) fluorescent light (700-900 nm) has the potential to improve cancer surgery outcomes, minimize the time patients are under anaesthesia and lower health-care costs largely by way of its improved contrast and depth of tissue penetration relative to visible light. Accordingly, the past few years have witnessed an explosion of proof-of-concept clinical trials in the field. In this Review, we introduce the concept of NIR fluorescence imaging for cancer surgery, examine the clinical trial literature to date and outline the key issues pertaining to imaging system and contrast agent optimization. Although NIR seems to be superior to many traditional imaging techniques, its incorporation into routine care of patients with cancer depends on rigorous clinical trials and validation studies.

Micro-computed tomography and nuclear magnetic resonance imaging for noninvasive, live-mouse cholangiography

The cholangiopathies are a diverse group of biliary tract disorders, many of which lack effective treatment. Murine models are an important tool for studying their pathogenesis, but existing noninvasive methods for assessing biliary disease in vivo are not optimal. Here we report our experience with using micro-computed tomography (microCT) and nuclear magnetic resonance (MR) imaging to develop a technique for live-mouse cholangiography. Using mdr2 knockout (mdr2KO, a model for primary sclerosing cholangitis (PSC)), bile duct-ligated (BDL), and normal mice, we performed in vivo: (1) microCT on a Siemens Inveon PET/CT scanner and (2) MR on a Bruker Avance 16.4 T spectrometer, using Turbo Rapid Acquisition with Relaxation Enhancement, IntraGate Fast Low Angle Shot, and Half-Fourier Acquisition Single-shot Turbo Spin Echo methods. Anesthesia was with 1.5-2.5% isoflurane. Scans were performed with and without contrast agents (iodipamide meglumine (microCT), gadoxetate disodium (MR)). Dissection and liver histology were performed for validation. With microCT, only the gallbladder and extrahepatic bile ducts were visualized despite attempts to optimize timing, route, and dose of contrast. With MR, the gallbladder, extra-, and intrahepatic bile ducts were well-visualized in mdr2KO mice; the cholangiographic appearance was similar to that of PSC (eg, multifocal strictures) and could be improved with contrast administration. In BDL mice, MR revealed cholangiographically distinct progressive dilation of the biliary tree without ductal irregularity. In normal mice, MR allowed visualization of the gallbladder and extrahepatic ducts, but only marginal visualization of the diminutive intrahepatic ducts. One mouse died during microCT and MR imaging, respectively. Both microCT and MR scans could be obtained in ≤20 min. We, therefore, demonstrate that MR cholangiography can be a useful tool for longitudinal studies of the biliary tree in live mice, whereas microCT yields suboptimal duct visualization despite requiring contrast administration. These findings support further development and application of MR cholangiography to the study of mouse models of PSC and other cholangiopathies.

Image-guided hepatopancreatobiliary surgery using near-infrared fluorescent light

Background

Improved imaging methods and surgical techniques have created a new era in hepatopancreatobiliary (HPB) surgery. Despite these developments, visual inspection, palpation, and intraoperative ultrasound remain the most utilized tools during surgery today. This is problematic, though, especially in laparoscopic HPB surgery, where palpation is not possible. Optical imaging using near-infrared (NIR) fluorescence can be used for the real-time assessment of both anatomy (e.g., sensitive detection and demarcation of tumours and vital structures) and function (e.g., assessment of luminal flow and tissue perfusion) during both open and minimally invasive surgeries.

Methods

This article reviews the published literature related to preclinical development and clinical applications of NIR fluorescence imaging during HPB surgery.

Results

NIR fluorescence imaging combines the use of otherwise invisible NIR fluorescent contrast agents and specially designed camera systems, which are capable of detecting these contrast agents during surgery. Unlike visible light, NIR fluorescent light can penetrate several millimetres through blood and living tissue, thus providing improved detectability. Applications of this technique during HPB surgery include tumour imaging in liver and pancreas, and real-time imaging of the biliary tree.

Conclusions

NIR fluorescence imaging is a promising new technique that may someday improve surgical accuracy and lower complications.

Advanced intraoperative imaging methods for laparoscopic anatomy navigation: an overview

BACKGROUND

Safety and efficiency are important topics in minimally invasive surgery. Apart from its advantages, laparoscopic surgery has the following drawbacks: two-dimensional imaging, challenging eye-hand coordination, and absence of tactile feedback. Enhanced imaging with earlier and clearer identification of essential tissue types can partly overcome these disadvantages. Research groups worldwide are investigating new technologies for image-guided surgery purposes. This review article gives an overview of current developments in surgical optical imaging for improved anatomic identification and physiologic tissue characterization during laparoscopic gastrointestinal surgery.

METHODS

A systematic literature search in the PubMed database was conducted. Eligible studies reported on any kind of novel optical imaging technique applied for anatomic identification or physiologic tissue characterization in laparoscopic gastrointestinal surgery. Gynecologic and urologic procedures also were included whenever vascular, nerve, ureter, or lymph node imaging was concerned.

RESULTS

Various surgical imaging techniques for enhanced intraoperative visualization of essential tissue types (i.e., blood vessel, bile duct, ureter, nerve, lymph node) and for tissue characterization purposes such as assessment of blood perfusion were identified. An overview of preclinical and clinical experiences is given as well as the potential added value for intraoperative anatomic localization and characterization during laparoscopy.

CONCLUSION

Implementation of new optical imaging methods during laparoscopic gastrointestinal surgery can improve intraoperative anatomy navigation. This may lead to increased patient safety (preventing iatrogenic functional tissue injury) and procedural efficiency (shorter operating time). Near-infrared fluorescence imaging seems to possess the greatest potential for implementation in clinical practice in the near future.

Indocyanine-green-loaded microballoons for biliary imaging in cholecystectomy

We encapsulate indocyanine green (ICG) in poly[(D,L-lactide-co-glycolide)-co-PEG] diblock (PLGA-PEG) microballoons for real-time fluorescence and hyperspectral imaging of biliary anatomy. ICG-loaded microballoons show superior fluorescence characteristics and slower degradation in comparison with pure ICG. The use of ICG-loaded microballoons in biliary imaging is demonstrated in both biliary-simulating phantoms and an ex vivo tissue model. The biliary-simulating phantoms are prepared by embedding ICG-loaded microballoons in agar gel and imaged by a fluorescence imaging module in a Da Vinci surgical robot. The ex vivo model consists of liver, gallbladder, common bile duct, and part of the duodenum freshly dissected from a domestic swine. After ICG-loaded microballoons are injected into the gallbladder, the biliary structure is imaged by both hyperspectral and fluorescence imaging modalities. Advanced spectral analysis and image processing algorithms are developed to classify the tissue types and identify the biliary anatomy. While fluorescence imaging provides dynamic information of movement and flow in the surgical region of interest, data from hyperspectral imaging allow for rapid identification of the bile duct and safe exclusion of any contaminant fluorescence from tissue not part of the biliary anatomy. Our experiments demonstrate the technical feasibility of using ICG-loaded microballoons for biliary imaging in cholecystectomy.

Visibility enhancement of common bile duct for laparoscopic cholecystectomy by vivid fiber-optic indication: a porcine experiment trial

Bile duct injury (BDI) is the most serious iatrogenic complication during laparoscopic cholecystectomy (LC) and occurs easily in inexperienced surgeons since the position of common bile duct (CBD) and its related ductal junctions are hard to precisely identify in the hepatic anatomy during surgery. BDI can be devastating, leading to chronic morbidity, high mortality, and prolonged hospitalization. In addition, it is the most frequent injury resulting in litigation and the most likely injury associated with a successful medical malpractice claim against surgeons. This study introduces a novel method for conveniently and rapidly indicating the anatomical location of CBD during LC by the direct fiber-optic illumination of 532-nm diode-pumped solid state laser through a microstructured plastic optical fiber to avoid the wrong identification of CBD and the injury from mistakenly cutting the CBD that can lead to permanent and even life threatening consequences. Six porcine were used for preliminary intra-CBD illumination experiments via laparotomy and direct duodenal incision to insert the invented CBD illumination laser catheter with nonharmful but satisfactory visual optical density.

Clinical application of fluorescence imaging of liver cancer using indocyanine green

Recently, fluorescence imaging using indocyanine green (ICG) has been applied to hepatobiliary surgery, not only to visualize the bile ducts, but also to identify liver cancer during surgery. In this technique, ICG is administered intravenously at a dose of 0.5 mg/kg body weight for routine liver function testing before surgery. Intraoperatively, liver cancer can be readily identified by fluorescence imaging on the liver surface before resection and on the cut surface of the resected specimen. This is achieved by visualizing fluorescence from the area of impaired bile excretion in hepatocellular cancer tissue and in the liver parenchyma surrounding metastatic liver cancers. Liver cancer navigation surgery, first developed in Japan, is also possible, and it represents one of the few fluorescence imaging techniques for cancer that have reached the stage of clinical application; with further developments in basic research, fluorescence imaging is expected to become an indispensable technique for the diagnosis and treatment of liver cancer.

Lipidots: competitive organic alternative to quantum dots for in vivo fluorescence imaging

The use of fluorescent nanostructures can bring several benefits on the signal to background ratio for in vitro microscopy, in vivo small animal imaging, and image-guided surgery. Fluorescent quantum dots (QDs) display outstanding optical properties, with high brightness and low photobleaching rate. However, because of their toxic element core composition and their potential long term retention in reticulo-endothelial organs such as liver, their in vivo human applications seem compromised. The development of new dye-loaded (DiO, DiI, DiD, DiR, and Indocyanine Green (ICG)) lipid nanoparticles for fluorescence imaging (lipidots) is described here. Lipidot optical properties quantitatively compete with those of commercial QDs (QTracker(®)705). Multichannel in vivo imaging of lymph nodes in mice is demonstrated for doses as low as 2 pmols of particles. Along with their optical properties, fluorescent lipidots display very low cytotoxicity (IC(50) > 75 nM), which make them suitable tools for in vitro, and especially in vivo, fluorescence imaging applications.

Intraoperative assessment of biliary anatomy for prevention of bile duct injury: a review of current and future patient safety interventions

Background

Bile duct injury (BDI) is a dreaded complication of cholecystectomy, often caused by misinterpretation of biliary anatomy. To prevent BDI, techniques have been developed for intraoperative assessment of bile duct anatomy. This article reviews the evidence for the different techniques and discusses their strengths and weaknesses in terms of efficacy, ease, and cost-effectiveness.

Method

PubMed was searched from January 1980 through December 2009 for articles concerning bile duct visualization techniques for prevention of BDI during laparoscopic cholecystectomy.

Results

Nine techniques were identified. The critical-view-of-safety approach, indirectly establishing biliary anatomy, is accepted by most guidelines and commentaries as the surgical technique of choice to minimize BDI risk. Intraoperative cholangiography is associated with lower BDI risk (OR 0.67, CI 0.61–0.75). However, it incurs extra costs, prolongs the operative procedure, and may be experienced as cumbersome. An established reliable alternative is laparoscopic ultrasound, but its longer learning curve limits widespread implementation. Easier to perform are cholecystocholangiography and dye cholangiography, but these yield poor-quality images. Light cholangiography, requiring retrograde insertion of an optical fiber into the common bile duct, is too unwieldy for routine use. Experimental techniques are passive infrared cholangiography, hyperspectral cholangiography, and near-infrared fluorescence cholangiography. The latter two are performed noninvasively and provide real-time images. Quantitative data in patients are necessary to further evaluate these techniques.

Conclusions

The critical-view-of-safety approach should be used during laparoscopic cholecystectomy. Intraoperative cholangiography or laparoscopic ultrasound is recommended to be performed routinely. Hyperspectral cholangiography and near-infrared fluorescence cholangiography are promising novel techniques to prevent BDI and thus increase patient safety.

In situ fluorescence imaging of myelination

We describe a novel fluorescent dye, 3-(4-aminophenyl)-2H-chromen-2-one (termed case myelin compound or CMC), that can be used for in situ fluorescent imaging of myelin in the vertebrate nervous system. When administered via intravenous injection into the tail vein, CMC selectively stained large bundles of myelinated fibers in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, CMC readily entered the brain and selectively localized in myelinated regions such as the corpus callosum and cerebellum. CMC also selectively stained myelinated nerves in the PNS. The staining patterns of CMC in a hypermyelinated mouse model were consistent with immunohistochemical staining. Similar to immunohistochemical staining, CMC selectively bound to myelin sheaths present in the white matter tracts. Unlike CMC, conventional antibody staining for myelin basic protein also stained oligodendrocyte cytoplasm in the striatum as well as granule layers in the cerebellum. In vivo application of CMC was also demonstrated by fluorescence imaging of myelinated nerves in the PNS.