[Intraoperative fluorescence angiography and cholangiography with indocyanine green in hepatobiliary surgery]

Pay attention to the application of indocyanine green fluorescence imaging technology in laparoscopic liver cancer resection

Traditional laparoscopic liver cancer resection faces challenges, such as difficulties in tumor localization and accurate marking of liver segments, as well as the inability to provide real-time intraoperative navigation. This approach falls short of meeting the demands for precise and anatomical liver resection. The introduction of fluorescence imaging technology, particularly indocyanine green, has demonstrated significant advantages in visualizing bile ducts, tumor localization, segment staining, microscopic lesion display, margin examination, and lymph node visualization. This technology addresses the inherent limitations of traditional laparoscopy, which lacks direct tactile feedback, and is increasingly becoming the standard in laparoscopic procedures. Guided by fluorescence imaging technology, laparoscopic liver cancer resection is poised to become the predominant technique for liver tumor removal, enhancing the accuracy, safety and efficiency of the procedure.

Effects of Indocyanine Green (ICG) Imaging-Assisted Cholecystectomy on Intraoperative and Postoperative Complications: A meta-Analysis

BACKGROUND

Accurate recognition of Calot's triangle during cholecystectomy is important in preventing intraoperative and postoperative complications. The use of indocyanine green (ICG) fluorescence imaging has become increasingly prevalent in cholecystectomy procedures. Our study aimed to evaluate the specific effects of ICG-assisted imaging in reducing complications.

MATERIALS AND METHODS

A comprehensive search of databases including PubMed, Web of Science, Europe PMC, and WANFANGH DATA was conducted to identify relevant articles up to July 5, 2023. Review Manager 5.3 software was applied to statistical analysis.

RESULTS

Our meta-analysis of 14 studies involving 3576 patients compared the ICG group (1351 patients) to the control group (2225 patients). The ICG group had a lower incidence of postoperative complications (4.78% vs 7.25%; RR .71; 95%CI: .54-.95; P = .02). Bile leakage was significantly reduced in the ICG group (.43% vs 2.02%; RR = .27; 95%CI: .12-.62; I2 = 0; P = .002), and they also had a lower bile duct drainage rate (24.8% vs 31.8% RR = .64, 95% CI: .44-.91, P = .01). Intraoperative complexes showed no statistically significant difference between the 2 groups (1.16% vs 9.24%; RR .17; 95%CI .03-1.02), but the incidence of intraoperative bleeding is lower in the ICG group.

CONCLUSION

ICG fluorescence imaging-assisted cholecystectomy was associated with a range of benefits, including a lower incidence of postoperative complications, decreased rates of bile leakage, reduced bile duct drainage, fewer intraoperative complications, and reduced intraoperative bleeding.

Indocyanine green fluorescence imaging as a predictor of long-term testicular atrophy in testicular torsion: a pilot study

PURPOSE

This pilot study evaluated indocyanine green-guided near-infrared fluorescence (ICG-NIRF) imaging of testicular blood flow to predict long-term testicular atrophy after testicular torsion (TT) surgery.

METHODS

The subjects of this retrospective study were patients who underwent surgery for TT at our hospital between December, 2020 and July, 2022. After detorsion, testicular blood flow was evaluated by ICG-NIRF imaging and classified into three categories: fluorescence detected, no fluorescence detected, and fluorescence detected only in the tunica albuginea vessels. Testicular volume was measured by ultrasonography up to 12 months after surgery to evaluate long-term outcomes.

RESULTS

Twelve patients were included in this analysis. We found a 100% correlation between the absence of ICG-NIRF signals and subsequent testicular atrophy. In three patients without an ICG-NIRF signal, the median testis size 12 months postoperatively was significantly smaller (16.5% of the contralateral testis; range 13-20%) than that in six patients with an ICG-NIRF signal (96%; 89-115%) (p = 0.013). Mild atrophy (74.5%; 73-76%) was also observed in the three patients for whom an ICG-NIRF signal was detected only in the tunica albuginea vessels.

CONCLUSIONS

Our pilot study highlights the potential of ICG-NIRF imaging as a prognostic tool for guiding surgical decision-making for patients with TT, by predicting postoperative testicular atrophy.

Educational Review: Intraoperative Parathyroid Fluorescence Detection Technology in Thyroid and Parathyroid Surgery

BACKGROUND

Accurate parathyroid gland (PG) identification is a critical yet challenging component of cervical endocrine procedures. PGs possess strong near-infrared autofluorescence (NIRAF) compared with other tissues in the neck. This property has been harnessed by image- and probe-based near-infrared fluorescence detection systems, which have gained increasing popularity in clinical use for their ability to accurately aid in PG identification in a rapid, noninvasive, and cost-effective manner. All NIRAF technologies, however, cannot differentiate viable from devascularized PGs without the use of contrast enhancement. Here, we aim to provide an overview of the rapid evolution of these technologies and update the surgery community on the most recent advancements in the field.

METHODS

A PubMed literature review was performed using the key terms "parathyroid," "near-infrared," and "fluorescence." Recommendations regarding the use of these technologies in clinical practice were developed on the basis of the reviewed literature and in conjunction with expert surgeons' opinions.

RESULTS

The use of near-infrared fluorescence detection can be broadly categorized as (1) using parathyroid NIRAF to identify both healthy and diseased PGs, and (2) using contrast-enhanced (i.e., indocyanine green) near-infrared fluorescence to evaluate PG perfusion and viability. Each of these approaches possess unique advantages and disadvantages, and clinical trials are ongoing to better define their utility.

CONCLUSIONS

Near-infrared fluorescence detection offers the opportunity to improve our collective ability to identify and preserve PGs intraoperatively. While additional work is needed to propel this technology further, we hope this review will be valuable to the practicing surgeon.

In vivo fluorescence imaging: success in preclinical imaging paves the way for clinical applications

Advances in diagnostic imaging have provided unprecedented opportunities to detect diseases at early stages and with high reliability. Diagnostic imaging is also crucial to monitoring the progress or remission of disease and thus is often the central basis of therapeutic decision-making. Currently, several diagnostic imaging modalities (computed tomography, magnetic resonance imaging, and positron emission tomography, among others) are routinely used in clinics and present their own advantages and limitations. In vivo near-infrared (NIR) fluorescence imaging has recently emerged as an attractive imaging modality combining low cost, high sensitivity, and relative safety. As a preclinical tool, it can be used to investigate disease mechanisms and for testing novel diagnostics and therapeutics prior to their clinical use. However, the limited depth of tissue penetration is a major challenge to efficient clinical use. Therefore, the current clinical use of fluorescence imaging is limited to a few applications such as image-guided surgery on tumors and retinal angiography, using FDA-approved dyes. Progress in fluorophore development and NIR imaging technologies holds promise to extend their clinical application to oncology, cardiovascular diseases, plastic surgery, and brain imaging, among others. Nanotechnology is expected to revolutionize diagnostic in vivo fluorescence imaging through targeted delivery of NIR fluorescent probes using antibody conjugation. In this review, we discuss the latest advances in in vivo fluorescence imaging technologies, NIR fluorescent probes, and current and future clinical applications.

The Role of ICG in Robot-Assisted Liver Resections

Introduction: Robotic-assisted liver surgery (RALS) with its known limitations is gaining more importance. The fluorescent dye, indocyanine green (ICG), is a way to overcome some of these limitations. It accumulates in or around hepatic masses. The integrated near-infrared cameras help to visualize this accumulation. We aimed to compare the influence of ICG staining on the surgical and oncological outcomes in patients undergoing RALS. Material and Methods: Patients who underwent RALS between 2014 and 2021 at the Department of General Surgery at the University Hospital Schleswig-Holstein, Campus Kiel, were included. In 2019, ICG-supported RALS was introduced. Results: Fifty-four patients were included, with twenty-eight patients (50.9%) receiving preoperative ICG. Hepatocellular carcinoma (32.1%) was the main entity resected, followed by the metastasis of colorectal cancers (17%) and focal nodular hyperplasia (15.1%). ICG staining worked for different tumor entities, but diffuse staining was noted in patients with liver cirrhosis. However, ICG-supported RALS lasted shorter (142.7 ± 61.8 min vs. 246.4 ± 98.6 min, p < 0.001), tumors resected in the ICG cohort were significantly smaller (27.1 ± 25.0 mm vs. 47.6 ± 35.2 mm, p = 0.021) and more R0 resections were achieved by ICG-supported RALS (96.3% vs. 80.8%, p = 0.075). Conclusions: ICG-supported RALS achieve surgically and oncologically safe results, while overcoming the limitations of RALS.

Indocyanine green staining for intraoperative perfusion assessment

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

Influence of intraoperative vasopressor use on indocyanine green fluorescence angiography: first evaluation in an experimental model

Intraoperative indocyanine green (ICG) fluorescence angiography has gained popularity and acceptance in many surgical fields for the real-time assessment of tissue perfusion. Although vasopressors have the potential to preclude an accurate assessment of tissue perfusion, there is a lack of literature with regards to its effect on ICG fluorescence angiography. An experimental porcine model was used to expose the small bowel for quantitative tissue perfusion assessment. Three increasing doses of norepinephrine infusion (0.1, 0.5, and 1.0 µg/kg/min) were administered intravenously over a 25-min interval. Time-to-peak fluorescence intensity (TTP) was the primary outcome. Secondary outcomes included absolute fluorescence intensity and local capillary lactate (LCL) levels. Five large pigs (mean weight: 40.3 ± 4.24 kg) were included. There was no significant difference in mean TTP (in seconds) at baseline (4.23) as compared to the second (3.90), third (4.41), fourth (4.60), and fifth ICG assessment (5.99). As a result of ICG accumulation, the mean and the maximum absolute fluorescence intensity were significantly different as compared to the baseline assessment. There was no significant difference in LCL levels (in mmol/L) at baseline (0.74) as compared to the second (0.82), third (0.64), fourth (0.60), and fifth assessment (0.62). Increasing doses of norepinephrine infusion have no significant influence on bowel perfusion using ICG fluorescence angiography.

Usability of Indocyanine Green in Robot-Assisted Hepatic Surgery

Recent developments in robotic surgery have led to an increasing number of robot-assisted hepatobiliary procedures. However, a limitation of robotic surgery is the missing haptic feedback. The fluorescent dye indocyanine green (ICG) may help in this context, which accumulates in hepatocellular cancers and around hepatic metastasis. ICG accumulation may be visualized by a near-infrared camera integrated into some robotic systems, helping to perform surgery more accurately. We aimed to test the feasibility of preoperative ICG application and its intraoperative use in patients suffering from hepatocellular carcinoma and metastasis of colorectal cancer, but also of other origins. In a single-arm, single-center feasibility study, we tested preoperative ICG application and its intraoperative use in patients undergoing robot-assisted hepatic resections. Twenty patients were included in the final analysis. ICG staining helped in most cases by detecting a clear lesion or additional metastases or when performing an R0 resection. However, it has limitations if applied too late before surgery and in patients suffering from severe liver cirrhosis. ICG staining may serve as a beneficial intraoperative aid in patients undergoing robot-assisted hepatic surgery. Dose and time of application and standardized fluorescence intensity need to be further determined.