The use of intravenous indocyanine green in minimally invasive segmental lung resections: a systematic review

Background

To identify intersegmental planes (ISPs) in video/robot-assisted thoracoscopic segmentectomies, indocyanine green (ICG) is commonly used. The aim of this systematic review is to evaluate the efficacy of intravenous ICG in the identification of ISP.

Methods

A systematic search was performed. Studies evaluating patients who underwent a video/robot-assisted thoracoscopic segmentectomy using intravenous ICG were included. The primary outcome measure was the frequency and percentage of patients in whom the ISP was adequately visualized. Secondary outcomes encompassed the ICG dose, time to visualization, time to maximum ICG visualization, time to disappearance of ICG effect and adverse reactions to ICG.

Results

Eighteen studies were included for systematic review, enrolling a total of 1,090 patients. Irrespective of the injected dose, intravenous ICG identified the ISP in 94% of the cases (range, 30-100%). Overall, there was a considerable amount of heterogeneity regarding the injected dose of ICG (range, 5-25 mg or 0.05-0.5 mg/kg). The mean time before first effect of ICG was visible ranged from 10 to 40 seconds. The mean total time of ICG visibility ranged from 90 to 140 seconds after a bolus injection and was 170 seconds after continuous infusion. No adverse reactions were reported.

Conclusions

After administration of intravenous ICG, visualization of the ISP is successful in up to 94% of cases, even after administration of a low dose (0.05 mg/kg) of ICG. The use of intravenous ICG is safe with no reported adverse effects in the immediate peri-operative period.

The effect of hypotonic pharmacologic lipodissolution on abdominal free flap perfusion: a case report

Background

Hypotonic pharmacologic lipodissolution (HPL) has gained popularity as a treatment for abdominal fat reduction, especially among Asian individuals. However, research on the effect of HPL on abdominal vascularity and abdominal autologous tissue flap are limited.

Case Description

This case report describes a patient who underwent HPL treatment in November 2022 and subsequently underwent nipple-sparing mastectomy with free transverse rectus abdominis musculocutaneous (TRAM) flap reconstruction on April 4, 2023. The preoperative evaluation included computed tomography (CT) angiography to assess the viability of abdominal perforators and vasculature for TRAM flap reconstruction. Intraoperatively, indocyanine green (ICG) fluoroscopy was performed after TRAM flap elevation to evaluate flap perfusion. The findings revealed compromised skin-side perfusion but satisfactory deep layer perfusion, with subdermal plexus perfusion observed during de-epithelialization.

Conclusions

These findings suggest that in nipple sparing mastectomy cases with minimal skin flap preservation requirements, a history of HPL may have less negative impact on TRAM flap reconstruction. However, in skin sparing mastectomy cases with extensive skin flap preservation needs, careful assessment, including preoperative CT angiography and intraoperative ICG imaging, is essential to minimize the risk of partial flap necrosis.

Utility of indocyanine green fluorescent dye in emergency general surgery: a review of the contemporary literature

For decades, indocyanine green (ICG) has been available for medical and surgical use. The indications for ICG use in surgery have expanded where guided surgery directed by fluorescence and near-infrared fluorescent imaging offers numerous advantages. Recently, surgeons have reported using ICG operative navigation in the emergency setting, with fluorescent cholangiography being the most common procedure. The utility of ICG also involves real-time perfusion assessment, such as ischemic organs and limbs. The rising use of ICG in surgery can be explained by the ICG's rapid technological evolution, accuracy, ease of use, and great potential to guide precision surgical diagnosis and management. The review aims to summarize the current literature on the uses of ICG in emergency general surgery. It provides a comprehensive and practical summary of the use of ICG, including indication, route of administration, and dosages. To simplify the application of ICG, we subdivided its use into anatomical mapping and perfusion assessment. Anatomical mapping includes the biliary tree, ureters, and bowel. Perfusion assessment includes bowel, pancreas, skin and soft tissue, and gonads. This review provides a reference to emergency general surgeons to aid in implementing ICG in the emergency setting for more enhanced and safer patient care.

Indocyanine-Green-Loaded Liposomes for Photodynamic and Photothermal Therapies: Inducing Apoptosis and Ferroptosis in Cancer Cells with Implications beyond Oral Cancer

Oral cancer represents a global health burden, necessitating novel therapeutic strategies. Photodynamic and photothermal therapies using indocyanine green (ICG) have shown promise due to their distinctive near-infrared (NIR) light absorption characteristics and FDA-approved safety profiles. This study develops ICG-loaded liposomes (Lipo-ICGs) to further explore their potential in oral cancer treatments. We synthesized and characterized the Lipo-ICGs, conducted in vitro cell culture experiments to assess cellular uptake and photodynamic/photothermal effects, and performed in vivo animal studies to evaluate their therapeutic efficacy. Quantitative cell apoptosis and gene expression variation were further characterized using flow cytometry and RNA sequencing, respectively. Lipo-ICGs demonstrated a uniform molecular weight distribution among particles. The in vitro studies showed a successful internalization of Lipo-ICGs into the cells and a significant photodynamic treatment effect. The in vivo studies confirmed the efficient delivery of Lipo-ICGs to tumor sites and successful tumor growth inhibition following photodynamic therapy. Moreover, light exposure induced a time-sensitive photothermal effect, facilitating the further release of ICG, and enhancing the treatment efficacy. RNA sequencing data showed significant changes in gene expression patterns upon Lipo-ICG treatment, suggesting the activation of apoptosis and ferroptosis pathways. The findings demonstrate the potential of Lipo-ICGs as a therapeutic tool for oral cancer management, potentially extending to other cancer types.

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

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

Laparoscopic Duodenum-Preserving Pancreatic Head Resection: A Technique for the Treatment of Benign or Low-Grade Malignant Tumors (10 Cases Report)

Background: Laparoscopic duodenum-preserving pancreatic head resection (LDPPHR) is a surgical procedure that involves the removal of the pancreatic head while aiming to preserve the integrity of the digestive and biliary tracts. With advancements in laparoscopic techniques, the utilization of LDPPHR has been increasing. Methods: We retrospectively analyzed the clinical data of 10 patients who underwent laparoscopic duodenum-preserving total pancreatic head resection (LDPPHR-t) at our center from June 2019 to October 2021. Additionally, we analyzed the use of indocyanine green (ICG) in the initial stage of LDPPHR, based on current reports. Results: LDPPHR-t was successfully performed in all patients. After surgery, 3 patients experienced pancreatic fistula (Grade B), 2 patients experienced bile leakage, and 2 patients experienced postoperative hemorrhage. However, no patient exhibited recurrence or required secondary surgery. Conclusion: LDPPHR-t is a new method for treating benign and low-grade malignant tumors in the pancreatic head. However, it is associated with a high incidence of postoperative complications. In the initial stage, the use of ICG can assist surgeons in identifying the biliary duct and pancreaticoduodenal artery arcade.

A human serum albumin-indocyanine green complex offers improved tumor identification in fluorescence-guided surgery

Background

Complete tumor removal is critical for achieving a good prognosis in patients but remains challenging for surgeons. Near-infrared fluorescence-guided surgery (NIRFGS) enables surgeons to accurately localize tumors in real time and facilitates accurate resection. Indocyanine green (ICG) has been approved by the U.S. Food and Drug Administration and the National Medical Products Administration for many years. Although the application of ICG has progressed for a variety of surgeries, there are inherent limitations to ICG, including poor water solubility and photostability, short blood half-life, and aggregation in blood, resulting in poor imaging performance. We found that mixing ICG with human serum albumin (HSA) preoperatively and then injecting it can improve the imaging performance.

Methods

We prepared fluorescent probes by combining ICG with HSA and identified their optimal ratio via in vitro absorption measurement and emission spectrum characterization of ICG-HSA complex with different mixing ratios and concentration gradients. Subsequently, under the optimal ratio and clinical simulated concentration, we conducted dynamic change analysis of the fluorescence spectral properties after mixing. We then compared the uptake of ICG-HSA in vitro for two different cell types and the imaging performance of different molar ratios of ICG and HSA in mouse models.

Results

Through in vitro absorption and emission spectrum characterization of ICG-HSA mixtures with different mixing ratios and concentration gradients, the optimal ratio of the mixture was obtained (ICG:HSA =4:5). Using this ratio, clinical simulated concentration, and mixing, we completed the dynamic change analysis of the fluorescence spectrum properties. The results verified that HSA can improve the dispersion and stability of ICG in aqueous solution, reduce the proportion of free-state ICG, and thus improve the biodistribution. Moreover, the fluorescence performance of ICG was improved. ICG-HSA and ICG uptake in MDA-MB-231 cells and imaging in vivo showed that HSA increased the enrichment of ICG in tumor compared to ICG alone (ICG-HSAfluorescence intensity =237.3±10.7 vs. ICGfluorescence intensity =127.1±10.7). Compared with ICG alone, ICG-HSA provided a clearer tumor boundary and higher tumor-to-background ratio (TBR) (ICG-HSATBRmax 3.49±0.56 vs. ICGTBRmax 1.94±0.23).

Conclusions

This study suggests that ICG-HSA can achieve higher tumor-to-background contrast with shorter time and can provide an overall superior imaging performance compared to ICG alone, thus exhibiting considerable potential for clinical application.

Bladder cancer with urinary diversion by a sigmoid colon conduit after transverse colon stoma

Introduction

Sigmoid conduit is one of the methods for achieving urinary diversion, but it is performed less frequently than ileal conduit and ureterostomy. Herein, we report a case in which a sigmoid colon conduit was performed after nephrostomy and transverse colostomy.

Case presentation

A 70-year-old man was referred to our hospital because of a bladder tumor. Computed tomography and transurethral biopsy revealed advanced bladder cancer with ureteral and rectal invasion. Despite drug therapy, the tumor progressed. Thus, nephrostomy and transverse colostomy were performed for urinary and fecal diversion, respectively. Subsequently, chemotherapy was administered for 8 months. As nephrostomy-related complications occurred frequently during chemotherapy, a sigmoid colon conduit was performed instead of nephrostomy for urinary diversion to improve the patient's quality of life.

Conclusion

In patients with advanced bladder cancer requiring a double stoma of the urinary and fecal tracts, sigmoid colon conduit may be selected as a urinary diversion method.

Imaging Modalities for Evaluating Lymphedema

Lymphedema is a progressive condition. Its therapy aims to reduce edema, prevent its progression, and provide psychosocial aid. Nonsurgical treatment in advanced stages is mostly insufficient. Therefore-in many cases-surgical procedures, such as to restore lymph flow or excise lymphedema tissues, are the only ways to improve patients' quality of life. Imaging modalities: Lymphoscintigraphy (LS), near-infrared fluorescent (NIRF) imaging-also termed indocyanine green (ICG) lymphography (ICG-L)-ultrasonography (US), magnetic resonance lymphangiography (MRL), computed tomography (CT), photoacoustic imaging (PAI), and optical coherence tomography (OCT) are standardized techniques, which can be utilized in lymphedema diagnosis, staging, treatment, and follow-up. Conclusions: The combined use of these imaging modalities and self-assessment questionnaires deliver objective parameters for choosing the most suitable surgical therapy and achieving the best possible postoperative outcome.

Personalised indocyanine-guided lymphadenectomy for prostate cancer: a randomised clinical trial

OBJECTIVES

To study the safety and efficacy of a personalised indocyanine-guided pelvic lymph node dissection (PLND) against extended PLND (ePLND) during radical prostatectomy (RP).

PATIENTS AND METHODS

Patients who were candidates for RP and lymphadenectomy, with intermediate- or high-risk prostate cancer (PCa) according to the National Comprehensive Cancer Network guidelines, were enrolled in this randomised clinical trial. Randomisation was made 1:1 to indocyanine green (ICG)-PLND (only ICG-stained LNs) or ePLND (obturator fossa, external, internal, and common iliac and presacral LNs). The primary endpoint was the complication rate within 3 months after RP. Secondary endpoints included: rate of major complications (Clavien-Dindo Grade III-IV), time to drainage removal, length of stay, percentage of patients classified as pN1, number of LNs removed, number of metastatic LNs, rate of patients with undetectable prostate-specific antigen (PSA), biochemical recurrence (BCR)-free survival, and rate of patients with androgen-deprivation therapy at 24 months.

RESULTS

A total of 108 patients were included with a median follow-up of 16 months. In all, 54 were randomised to ICG-PLND and 54 to ePLND. The postoperative complication rate was higher in the ePLND (70%) vs the ICG-PLND group (32%) (P < 0.001). Differences between major complications in both groups were not statically significant (P = 0.7). The pN1 detection rate was higher in the ICG-PLND group (28%) vs the ePLND group (22%); however, this difference was not statistically significant (P = 0.7). The rate of undetectable PSA at 12 months was 83% in the ICG-PLND vs 76% in the ePLND group, which was not statistically significant. Additionally, there were no statistically significant differences in BCR-free survival between groups at the end of the analysis.

CONCLUSIONS

Personalised ICG-guided PLND is a promising technique to stage patients with intermediate- and high-risk PCa properly. It has shown a lower complication rate than ePLND with similar oncological outcomes at short-term follow-up.

Complete visualization using indocyanine green in thoracic surgery for pulmonary sequestration

Preoperative three-dimensional computed tomography (CT) facilitates accurate identification of aberrant systemic arteries in thoracic surgery for pulmonary sequestration (PS). Furthermore, the boundary between normal and sequestrated lungs can be visualized using the spread of fluorescent indocyanine green (ICG) when performing surgery for PS. This study aimed to determine how to completely visualize anatomical variations, safely treat aberrant arteries, remove only sequestrated lungs, and perform minimally invasive surgery for PS. Seventeen patients underwent lung resection for intralobar PS at our institution between 2009 and 2022. We retrospectively reviewed the surgical outcomes and intraoperative images using ICG to assess the efficacy and feasibility of near-infrared fluorescence imaging. Since 2019, intraoperative near-infrared fluorescence imaging with ICG has been used in six patients, including four females and two males (median age, 56 years), to visualize the boundary between normal and sequestrated lungs. Aberrant arteries were identified using preoperative three-dimensional CT, and the boundary between sequestrated and normal lungs could be clearly delineated intraoperatively using ICG in all cases. The median operative time was 145 min (range, 88-167 min), and the median blood loss was 5 mL (range, 1-191 mL). The overlay mode using near-infrared thoracoscopy, which merges visible light images with fluorescent images, was safer and more useful than conventional thoracoscopy for delineating boundaries with electrocautery. No intraoperative or postoperative complications occurred. The median postoperative hospital stay was 5 days (range, 3-7 days). Intraoperative identification of the boundary between normal and sequestrated lungs using ICG was simple and feasible. We suggested that this technique was effective for lesion resection and normal lung preservation during surgery for intralobar PS.

Study on the application value of fluorescent laparoscopy in pancreatic tumor surgery

Background

Fluorescent laparoscopy is rarely used in pancreatic surgery. The aim of this study was to investigate the value of fluorescent laparoscopy in pancreatic tumor surgery.

Methods

A total of 19 patients with pancreatic tumors who were treated in the Department of Hepatobiliary Surgery at the First Affiliated Hospital of Wannan Medical College from January 2021 to August 2022 were selected. Fluorescent laparoscopy was used intraoperatively, and the imaging characteristics of different tumors were recorded and analyzed.

Results

Among the 19 participants, postoperative pathology confirmed 12 cases of pancreatic cancer (8 cases of moderately differentiated adenocarcinoma, 3 cases of moderately-poorly differentiated adenocarcinoma, and 1 case of acinar cell carcinoma), 4 cases of pancreatic cystic tumors (1 case of microcystic serous cystadenoma, 1 case of serous cystadenoma, 1 case of solid pseudopapillary tumor, and 1 case of solid-cystic pseudopapillary tumor), 1 case of pancreatic neuroendocrine tumor (G1 stage), and 2 cases of inflammatory lesions. There were 8 cases of pancreaticoduodenectomy, 6 cases of distal pancreatectomy, 3 cases of middle pancreatectomy, 1 case of local pancreatectomy, and 1 case of duodenum-preserving pancreatic head resection. One minute after intravenous injection of indocyanine green (ICG), 10 of the 12 patients with pancreatic cancer showed tumor peritumor imaging; 2 cases of pancreatic serous cystic tumors did not show imaging; 2 cases of solid pseudopapillary tumors had tumor body imaging; 1 case of neuroendocrine tumor had tumor body imaging, with complete fluorescence imaging after specimen dissection; there were 2 cases pathologically confirmed as inflammatory lesions, 1 case with tumor body imaging, and 1 case with capsule imaging.

Conclusions

By reasonably controlling the administration time and dose of ICG during surgery, some pancreatic tumors can be fluorescently imaged, which is beneficial for intraoperative tumor localization and margin determination.

DNA-Based Near-Infrared Voltage Sensors

Indocyanine green (ICG) is an FDA approved dye widely used for fluorescence imaging in research, surgical navigation, and medical diagnostics. However, ICG has a few drawbacks, such as concentration-dependent aggregation and absorbance, nonspecific cellular targeting, and rapid photobleaching. Here, we report a novel DNA-based nanosensor platform that utilizes monomers of ICG and cholesterol. Using DNA origami, we can attach ICG to a DNA structure, maintaining its concentration, preserving its near-infrared (NIR) absorbance, and allowing attachment of targeting moieties. We characterized the nanosensors' absorbance, stability in blood, and voltage sensing in vitro. This study presents a novel DNA-based ICG nanosensor platform for cellular voltage sensing for future in vivo applications.

Semi-Permanent Use of Indocyanine Green Latex Phantom for Fluorescence Emission

INTRODUCTION

Testing the fluorescence emission of the vascular circulation status of the indocyanine green (ICG) fluorescence contrast agent to validate the system performance is crucial. Hence, the development of an ICG phantom is imperative, and this study proposes a method for manufacturing an ICG phantom.

METHOD

The ICG with an initial concentration was subjected to 0.2 cc sampling through syringe(x), and an ICG (0.2 cc) is diluted with silicon (Si) latex lubber (10 mL) during the manufactured the phantom. The brightest fluorescence expression state is 30 μM, and if it exceeded 50 μM, fluorescence fading occurred and changed to a dark color.

RESULTS

The liquid (ICG) of the concentration range is 0.003 mM to 0.24 mM, and the maximum fluorescence expression range is 0.005 to 0.006 mM when the phantom is irradiated using a 780-nm (800 mW) LED. In addition, the fluorescence emission is reduced to 0.24 mM, and the fluorescence expression concentration is 10 μM, 30 μM, and 50 μM, respectively. The decreasing of the fluorescence emission is beginning to 50 μM.

CONCLUSIONS

In this study, the proposed phantom with ICG fluorescence emission using latex lubber is proposed. In this works, the proposed phantom is improved the performance for ICG fluorescence emission. In the manufactured phantom, the phantom is used for gelatin, and the advance of phantom has easy manufacturing and long-life fluorescence emission (semipermanent) due to incorrodible material (latex lubber). To experimental results of a phantom, the ICG fluorescent contrast medium (0.055 mM) is same to 30 μM. Then, the 0.055 mM and 30 μM have high resolution and fluorescence emission status. Thus, the results are in good agreement.

Combined indocyanine green and medical glue enables stable and precise position in animal studies: promising for fluorescence-guided pulmonary ground glass nodule resection

Background

Accurate preoperative localization of pulmonary nodules is crucial for surgical treatment. The use of indocyanine green (ICG) for localization is prone to thoracic contamination and spread, resulting in the eventual failure of localization. By using medical glue combined with ICG, we can accurately and permanently locate various tissues in animal study, which can provide evidences for clinical translations.

Methods

A series of medical glue and ICG volume ratios of 2:3, 3:3, 4:3, 6:3, and 9:3 were mixed and injected immediately into subcutaneous tissues of BALB/c nude mice; either medical glue or ICG was injected singly in the control group. Fluorescence intensity over time and boundary sharpness were investigated to determine the optimal ratio. Then, fluorescence guided resection of tissue was performed ex vivo on the pig intestine utilizing optimal ratio. Further, localization agents with the optimal ratio were injected into the organs of living mice, and fluorescence imaging for accurate positioning was performed 24 hours later.

Results

The localization agents with a volume ratio of 4:3 showed the best boundary sharpness and the strongest photostability. With the guidance of fluorescence navigation, the marked tissues were accurately separated and removed from the surrounding tissue both on mice and on pig intestines. In the organs of living mice, the localization agents (ratio 4:3) realized accurate positioning of marked tissues. Additionally, the medical glue limited the diffusion of ICG, promising to enable more stable and precise positioning of the nodules during surgery.

Conclusions

The combination of ICG and medical glue presents a superior approach when compared to the individual use of either ICG or medical glue. This technique offers enhanced precision and durability and sealed the wound, thereby mitigating the risk of pneumothorax following puncture procedures. This innovative technique optimizes the properties of medical adhesive to augment tissue density while harnessing the real-time fluorescent endoscopic marking capabilities of ICG during surgical interventions. By employing this innovative technique, it holds significant promise for augmenting the accuracy of pulmonary nodule localization in thoracoscopic surgery within future clinical applications.

Methods for the identification and preservation of parathyroid glands in thyroid surgery: a narrative review

Background and Objective

Accurate intraoperative identification and viability assessment of the parathyroid glands (PGs) has always been a crucial but challenging aspect of thyroid surgery. The traditional method, naked-eye (NE) assessment, is significantly associated with the experience of the surgeon. Therefore, various methods have been developed to help surgeons protect PGs, with some benefits and limitations. Recently, near-infrared autofluorescence (NIRAF) and indocyanine green fluorescence imaging (ICGFI) have been demonstrated to be promising in the identification and viability assessment of PGs. Herein, we provide an overview of the methods of intraoperative identification and viability assessment of PGs, focusing on the application of NIRAF and ICGFI.

Methods

We performed a systematic literature search of PubMed, Medline, Cochrane Library databases, Web of Science, and EMBASE to identify all relevant studies published up to March 2023. The keywords were ((autofluorescence) OR (indocyanine green)) AND (parathyroid gland).

Key Content and Findings

In this narrative review, we summarized the benefits and limitations of intraoperative methods for PG identification and viability assessment, focusing on the application of NIRAF and ICGFI.

Conclusions

Intraoperative parathyroid protection methods have developed from traditional subjective identification of PGs to the latest near-infrared (NIR) fluorescence imaging technology. The discovery, development, and application of NIRAF and ICGFI have provided better ways for surgeons to protect PGs intraoperatively.

Fluorescence-guided surgery with indocyanine green to identify an idiopathic chyle leak-case report

Background

Chylothorax is the leakage of chyle into the pleural space and is associated with up to 50% morbidity. Although, the identification of traumatic chylothoraces is well described, non-traumatic chylothoraxes, mostly idiopathic, present therapeutic challenges as they are difficult to localize. We describe an attempt at localizing and treating an idiopathic chylothorax refractory to conservative and minimally invasive techniques. This was done using indocyanine green (ICG) and was a joint case between a thoracic surgeon and an interventional radiologist.

Case Description

A 50-year-old female with a recent history of coronavirus disease (COVID)-19 presented with shortness of breath. She was found to have a right pleural effusion and was admitted to the hospital, where a chest tube was inserted and pleural fluid analysis confirmed the diagnosis of a chylothorax. Conservative management was attempted but with little success. Initial magnetic resonance lymphangiogram (MRL) revealed abnormal enhancing lymphatic masses in the right paraspinal thoracic space as well as lympho-venous junction obstruction with large neck collaterals. She then underwent percutaneous lympho-venous junction angioplasty followed by multiple rounds of glue embolization without clinical improvement. The decision was then made to proceed with a thoracotomy, identification of the site of thoracic duct (TD) leakage, and a mechanical pleurodesis assisted by intraoperative imaging. Ten mg of ICG was injected into the inguinal lymph nodes. Using a camera capable of detection of near-infrared (NIR) light, we were able to visualize the site from which the ICG was extravasating in the chest. Glue was then injected in that area to further help in reducing the leak. After keeping her nil per os (NPO) and requiring one more ligation, a repeat MRL showed a markedly decreased leak into the right pleural space. Two weeks later, she was seen in clinic and reported significant improvement in her symptoms.

Conclusions

This is the case of a 50-year-old female who was found to have a significant right chylothorax. She underwent conservative management, followed by tube thoracostomy, and TD ligation but was refractory to treatment. Fluorescence-guided surgery was pivotal to localize the leakage site and help seal it intraoperatively.

Use of Near-Infrared Fluorescence Techniques in Minimally Invasive Surgery for Colorectal Liver Metastases

Colorectal liver metastases (CRLM) afflict a significant proportion of patients with colorectal cancer (CRC), ranging from 25% to 30% of patients throughout the course of the disease. In recent years, there has been a surge of interest in the application of near-infrared fluorescence (NIRF) imaging as an intraoperative imaging technique for liver surgery. The utilisation of NIRF-guided liver surgery, facilitated by the administration of fluorescent dye indocyanine green (ICG), has gained traction in numerous medical institutions worldwide. This innovative approach aims to enhance lesion differentiation and provide valuable guidance for surgical margins. The use of ICG, particularly in minimally invasive surgery, has the potential to improve lesion detection rates, increase the likelihood of achieving R0 resection, and enable anatomically guided resections. However, it is important to acknowledge the limitations of ICG, such as its low specificity. Consequently, there has been a growing demand for the development of tumour-specific fluorescent probes and the advancement of camera systems, which are expected to address these concerns and further refine the accuracy and reliability of intraoperative fluorescence imaging in liver surgery. While NIRF imaging has been extensively studied in patients with CRLM, it is worth noting that a significant proportion of published research has predominantly focused on the detection of hepatocellular carcinoma (HCC). In this study, we present a comprehensive literature review of the existing literature pertaining to intraoperative fluorescence imaging in minimally invasive surgery for CRLM. Moreover, our analysis places specific emphasis on the techniques employed in liver resection using ICG, with a focus on tumour detection in minimal invasive surgery (MIS). Additionally, we delve into recent developments in this field and offer insights into future perspectives for further advancements.

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

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

Clinical application of indocyanine green fluorescence imaging navigation for pediatric renal cancer

Background

Indocyanine Green (ICG) fluorescence imaging has been widely used in the surgical treatment of adult renal cancers, but its application in pediatric renal cancers has rarely been reported. This study aims to summarize the experience of ICG fluorescence imaging in pediatric renal cancers and explores its safety and feasibility.

Methods

The clinical features, surgical information, ICG administration regimen, near infrared radiography data in vivo and ex vivo and pathological results of children with renal cancers using ICG navigation were analyzed and summarized.

Results

There were 7 cases of renal cancer, including 4 cases of Wilms tumor (WT), 1 case of malignant rhabdoid tumor of the kidney (MRTK) and 2 cases of renal cell carcinoma (RCC). By intraoperative intravenous injection of ICG from 2.5 to 5 mg (0.05-0.67 mg/kg), the tumors were visualized in 6 cases in vivo or ex vivo, and the tumor visualization failed in 1 case due to renal artery embolization before operation. By injecting 5 mg ICG into the normal renal tissue during the operation, 3 patients achieved fluorescent localization of sentinel lymph nodes. No ICG-related adverse reactions were found in any of the patients during or after operation.

Conclusions

ICG fluorescence imaging is safe and feasible for renal cancers in children. Intraoperative administration can achieve tumor and sentinel lymph node visualization which will facilitate the development of nephron sparing surgery (NSS). However, the technique is affected by ICG dose, anatomical conditions around the tumor, and renal blood flow. A proper dose of ICG and the complete removal of perirenal fat are helpful for the fluorescence imaging of the tumor. It has potential in the operation of renal cancer in children.

Detection of Tumour-Targeted IRDye800CW Tracer with Commercially Available Laparoscopic Surgical Systems

(1) Introduction: Near-infrared fluorescence (NIRF) combined with tumour-targeted tracers, such as bevacizumab-800CW, could aid surgical decision-making. This study explored the use of IRDye800CW, conjugated to bevacizumab, with four commercially available NIRF laparoscopes optimised for indocyanine green (ICG). (2) Methods: A (lymph node) phantom was made from a calibration device for NIRF and tissue-mimicking material. Serial dilutions of bevacizumab-800CW were made and ICG functioned as a reference. System settings, working distance, and thickness of tissue-mimicking material were varied to assess visibility of the fluorescence signal and tissue penetration. Tests were performed with four laparoscopes: VISERA ELITE II, Olympus; IMAGE1 S™ 4U Rubina, KARL STORZ; ENDOCAM Logic 4K platform, Richard Wolf; da Vinci Xi, Intuitive Surgical. (3) Results: The lowest visible bevacizumab-800CW concentration ranged between 13-850 nM (8-512 times diluted stock solution) for all laparoscopes, but the tracer was not visible through 0.8 cm of tissue in all systems. In contrast, ICG was still visible at a concentration of 0.4 nM (16,384 times diluted) and through 1.6-2.4 cm of tissue. Visibility and tissue penetration generally improved with a reduced working distance and manually adjusted system settings. (4) Conclusion: Depending on the application, bevacizumab-800CW might be sufficiently visible with current laparoscopes, but optimisation would widen applicability of tumour-targeted IRDye800CW tracers.

Mapping the Lymphatic Drainage Pattern of Esophageal Cancer with Near-Infrared Fluorescent Imaging during Robotic Assisted Minimally Invasive Ivor Lewis Esophagectomy (RAMIE)-First Results of the Prospective ESOMAP Feasibility Trial

While the sentinel lymph node concept is routinely applied in other surgical fields, no established and valid modality for lymph node mapping for esophageal cancer surgery currently exists. Near-infrared light fluorescence (NIR) using indocyanine green (ICG) has been recently proven to be a safe technology for peritumoral injection and consecutive lymph node mapping in small surgical cohorts, mostly without the usage of robotic technology. The aim of this study was to identify the lymphatic drainage pattern of esophageal cancer during highly standardized RAMIE and to correlate the intraoperative images with the histopathological dissemination of lymphatic metastases. Patients with clinically advanced stage squamous cell carcinoma or adenocarcinoma of the esophagus undergoing a RAMIE at our Center of Excellence for Surgery of the Upper Gastrointestinal Tract were prospectively included in this study. Patients were admitted on the day prior to surgery, and an additional EGD with endoscopic injection of the ICG solution around the tumor was performed. Intraoperative imaging procedures were performed using the Stryker 1688 or the FIREFLY fluorescence imaging system, and resected lymph nodes were sent to pathology. A total of 20 patients were included in the study, and feasibility and safety for the application of NIR using ICG during RAMIE were shown. NIR imaging to detect lymph node metastases can be safely performed during RAMIE. Further analyses in our center will focus on pathological analyses of ICG-positive tissue and quantification using artificial intelligence tools with a correlation of long-term follow-up data.

Near-infrared Fluorescence Imaging for Detecting Pancreatic Liver Metastasis in an Orthotopic Athymic Mouse Model

BACKGROUND/AIM

Evidence of metastatic disease precludes oncological resection of pancreatic cancer. Near-infrared (NIR) fluorescent labels, such as indocyanine green (ICG), assist in the intraoperative detection of occult and micrometastatic liver disease. The present study aimed to analyse the role of NIR fluorescence imaging using ICG for pancreatic liver disease as proof of concept in an orthotopic athymic mouse model.

MATERIALS AND METHODS

Pancreatic ductal adenocarcinoma was induced by injecting L3.6pl human pancreatic tumour cells into the pancreatic tail of seven athymic mice. After four weeks of tumour growth, ICG was injected into the tail vein and NIR fluorescence imaging was performed at harvest to determine tumour-to-liver ratios (TLR) using Quest Spectrum^® Fluorescence Imaging Platform.

RESULTS

Pancreatic tumour growth and liver metastasis could be visually confirmed for all seven animals. None of the hepatic metastases showed any detectable ICG-uptake. ICG-staining failed to visualize the liver metastases or to increase fluorescence intensity of the rim around the hepatic lesions.

CONCLUSION

ICG-staining fails to visualize liver metastases induced by L3.6pl pancreatic tumour cells in athymic nude mice by NIR fluorescence imaging. Further studies are necessary to delineate the underlying mechanism for insufficient ICG uptake in these pancreatic liver metastases and for the lack of a fluorescent rim around the liver lesions.

Indocyanine Green Fluorescence Guided Surgery in Colorectal Surgery

BACKGROUND

Indocyanine green (ICG) imaging has been increasingly used for intraoperative guidance in colorectal surgery over the past decade. The aim of this study was to review and organize, according to different type of use, all available literature on ICG guided colorectal surgery and highlight areas in need of further research and discuss future perspectives.

METHODS

PubMed, Scopus, and Google Scholar databases were searched systematically through November 2022 for all available studies on fluorescence-guided surgery in colorectal surgery.

RESULTS

Available studies described ICG use in colorectal surgery for perfusion assessment, ureteral and urethral assessment, lymphatic mapping, and hepatic and peritoneal metastases assessment. Although the level of evidence is low, results are promising, especially in the role of ICG in reducing anastomotic leaks.

CONCLUSIONS

ICG imaging is a safe and relatively cheap imaging modality in colorectal surgery, especially for perfusion assessment. Work is underway regarding its use in lymphatic mapping, ureter identification, and the assessment of intraperitoneal metastatic disease.

In vivo tumor ultrasound-switchable fluorescence imaging via intravenous injections of size-controlled thermosensitive nanoparticles

Near-infrared fluorescence imaging has emerged as a noninvasive, inexpensive, and ionizing-radiation-free monitoring tool for assessing tumor growth and treatment efficacy. In particular, ultrasound switchable fluorescence (USF) imaging has been explored with improved imaging sensitivity and spatial resolution in centimeter-deep tissues. This study achieved size control of polymer-based and indocyanine green (ICG) encapsulated USF contrast agents, capable of accumulating at the tumor after intravenous injections. These nanoprobes varied in size from 58 nm to 321 nm. The bioimaging profiles demonstrated that the proposed nanoparticles can efficiently eliminate the background light from normal tissue and show a tumor-specific fluorescence enhancement in the BxPC-3 tumor-bearing mice models possibly via the enhanced permeability and retention effect. In vivo tumor USF imaging further proved that these nanoprobes can effectively be switched 'ON' with enhanced fluorescence in response to a focused ultrasound stimulation in the tumor microenvironment, contributing to the high-resolution USF images. Therefore, our findings suggest that ICG-encapsulated nanoparticles are good candidates for USF imaging of tumors in living animals, indicating their great potential in optical tumor imaging in deep tissue.

The efficacy and safety of an indocyanine green-hyaluronic acid mixture (LuminoMark™) for localization in patients with non-palpable breast lesions: A multicenter, randomized, open-label, parallel phase 3 clinical trial

Purpose

The incidence of early tumor detection is increasing due to popularization of breast cancer screening and the development of imaging techniques. Thus, suitable preoperative localization is required for proper diagnosis and treatment of non-palpable breast lesions. The purpose of this study was to evaluate the efficacy and safety of indocyanine green (ICG)-hyaluronic acid (HA) mixture for lesion localization compared to activated charcoal.

Methods

This was a multicenter, randomized, open-label, parallel phase 3 clinical trial performed at four centers in Korea. Female patients scheduled for surgery to remove non-palpable breast lesions were enrolled. One hundred and nine patients were randomly assigned to a control group (activated charcoal: 0.3. - 1 mL) or a study group (ICG-HA mixture, 0.2 mL) for the localization of a breast lesion. The primary endpoint was the accuracy of resection. Secondary endpoints included the technical success rate, histopathological accuracy, skin pigmentation rate, and adverse event rate.

Results

A total of 104 patients were eligible for per-protocol analysis (control group, n = 51; study group, n = 53). The accuracy of resection in the study group was not inferior to that of the control group (90.57% vs. 98.04%, 95% confidence interval (CI): -2.31 - 18.91, p = 0.21). There was no statistically significant difference in technical success rate between the two groups (marking on breast skin: p = 0.11, marking on the excised specimen: p = 0.12). However, there were statistically significant differences in histopathological accuracy (0.26 ± 0.13 vs. 0.33 ± 0.17, p = 0.01) and skin pigmentation rate (0.00% vs. 30.77%, p< 0.01). Adverse events were not reported in either group.

Conclusions

When localization was performed using ICG-HA, the accuracy of resection was not inferior to that of activated charcoal. However, skin pigmentation rate was significantly lower. In conclusion, ICG-HA is effective and safe for localizing of non-palpable breast lesions.

Indocyanine green for targeted imaging of the gall bladder and fluorescence navigation

Researchers nowadays have devoted extra attention to the different biomedical applications of indocyanine green (ICG), a US Food and Drug Administration-approved fluorescent compound in the fields such as drug delivery, medical imaging and disease diagnosis. In addition, hepatic function evaluation could be conducted by using ICG before surgical procedures and angiographic assessment of blood. Therefore, ICG will be expected to be excellent imaging and targeting agent in various preclinical and clinical model systems. However, whether ICG possesses the potential for the gall bladder's intraoperative imaging guidance needs to be further explored in vivo animal experiments. Herein, near-infrared fluorophores ICG can display the specific uptake by the gall bladder cells and tissues. The dynamic process of biodistribution and the clearance of ICG in vivo in mice are clearly shown in real-time live-body imaging. Furthermore, ICG was rapidly excreted into the bile and lately biodistributed to the stomach after treatment in mice. Meanwhile, the signal-to-background ratio of the gall bladder demonstrated a tremendously higher level compared to other organs (stomach, heart, liver, lung, pancreas, spleen, intestine and duodenum). In conclusion, fluorescence navigation using ICG fluorescence imaging will provide good visualization and detection of the target lesions (gall bladder) in clinics such as diagnostic medical imaging and intraoperative navigation.

The role of fluorescence angiography in colonic interposition after esophagectomy

Colonic interposition is an alternative for gastric conduit reconstruction after esophagectomy. Anastomotic leakage (AL) occurs in 15-25% of patients and may be attributed to reduced blood supply after vascular ligation. Indocyanine green fluorescence angiography (ICG-FA) can visualize tissue perfusion. We aimed to give an overview of the first experiences of ICG-FA and AL rate in colonic interposition. This study included all consecutive patients who underwent a colonic interposition between January 2015 and December 2021 at a tertiary referral center. Surgery was performed for the following indications: inability to use the stomach because of previous surgery or extensive tumour involvement, cancer recurrence in the gastric conduit, or because of complications after initial esophagectomy. Since 2018 ICG-FA was performed before anastomotic reconstruction by administration of ICG injection (0.1 mg/kg/bolus), using the Spy-phi (Stryker, Kalamazoo, MI). Twenty-eight patients (9 female, mean age 62.8), underwent colonic interposition of whom 15 (54%) underwent ICG-FA-guided surgery. Within the ICG-FA group, three (20%) AL occurred, whereas in the non-ICG-FA group, three AL and one graft necrosis (31%) occurred (P=0.67). There was a change of management due to the FA assessment in three patients in the FA group (20%) which led to the choice of a different bowel segment for the anastomosis. Mean operative times in the ICG-FA and non-ICG-FA groups were 372±99 and 399±113 minutes, respectively (P=0.85). ICG-FA is a safe, easy and feasible technique to assess perfusion of colonic interpositions. ICG-FA is of added value leading to a change in management in a considerable percentage of patients. Its role in prevention of AL remains to be elucidated.

Laparoscopic left-sided mesocolic leaf flap repair for pelvic reconstruction after sacral tissue necrosis. A case report

Radical surgical procedures for malignant diseases of the pelvis result in a large pelvic defect that requires soft tissue reconstruction. The mesentery can be used for pelvic floor reconstruction when debridement with intestinal resection is required. A 75-year-old woman was diagnosed with sacral necrosis, infection and sepsis after carbon ion radiotherapy for sacral chordoma. She underwent sacral debridement three times, which resulted in a large pelvic defect of 14 × 13 cm. Surgery was performed to completely resect the necrotic tissue. We performed extended debridement of sacrum and adjacent tissue around the rectum and anus. Since it was impossible to preserve the anus, laparoscopic left hemicolectomy, abdominosacral resection, and left-sided mesocolic leaf repair for the pelvic defect, and reconstructed the pelvis and buttocks using a gluteal thigh flap were performed. Indocyanine green fluorescent (ICG) imaging was used to detect the margin of the pelvic floor and necrotic tissue and the blood flow of the left-sided mesocolic leaf flap. Left-sided mesocolic leaf reconstruction is useful for large pelvic defects. ICG imaging enabled the detection of the resection margins and the blood flow of the mesocolic leaf.

Safety and Efficacy of Indocyanine Green in Colorectal Cancer Surgery: A Systematic Review and Meta-Analysis of 11,047 Patients

Simple Summary

Indocyanine green (ICG) is a simple, inexpensive compound used in abdominal surgery, particularly advantageous in colorectal and rectal surgery, allowing intraoperative real-time assessment of the blood supply to the stumps of the large intestine after resection, and to the intestine after anastomosis in order to reduce the risk of anastomotic leak. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of ICG in colorectal cancer surgery in a group of 11,047 patients. The anastomotic leak rate in the ICG and non-ICG groups varied and amounted to 3.7% vs. 7.6% (p < 0.001) in all trials, 8.1% vs. 12.1% (p = 0.04) in randomized controlled trials (RCTs), and 3.1% vs. 7.3% (p < 0.001) in non-RCTs, respectively. Our meta-analysis shows that ICG perfusion assessment, with its safety, simplicity, and short time of adjustment, is a tool worth considering in decreasing the rate of complications after colorectal surgery.

Abstract

Despite the technological advances and improved surgical skills, the incidence of anastomotic leakage following colorectal cancer surgery still ranges from 4% to 19%. Therefore, we performed a systematic review and meta-analysis to evaluate the efficacy and safety of indocyanine green (ICG) use in colorectal cancer surgery. An online search of the Embase, MEDLINE, and Cochrane Central Register of Controlled Trials (CENTRAL) databases (from inception to 10 November 2021) was performed, in addition to manual screening. Thirty-two studies involving 11,047 patients were considered eligible for the meta-analysis. The anastomotic leak rate in the ICG and non-ICG groups varied and amounted to 3.7% vs. 7.6%, respectively (RR = 0.46; 95% CI: 0.39–0.56; p < 0.001). The rate in randomized controlled trials (RCTs) was 8.1% in the ICG group compared with 12.1% in the non-ICG group (RR = 0.67; 95% CI: 0.46–0.98; p = 0.04). In non-RCTs, it equaled 3.1% vs. 7.3%, respectively (RR = 0.43; 95% CI: 0.35–0.52; p < 0.001). Although the publications encompassed in our meta-analysis present different patients, with different factors influencing the results, a pooled analysis revealed a lower incidence of anastomotic leak in cases with ICG use. There are several other convincing advantages: safety, simplicity, and short time of the method adjustment. The presented meta-analysis indicates ICG perfusion assessment as a tool worth considering to decrease the rate of complications following colorectal surgery—valuable in the context of other, well-known risk factors.

The detection rate of methylene blue combined with another tracer in sentinel lymph node biopsy of early-stage breast cancer: a systematic review and network meta-analysis

Background

Methylene blue (MB) alone or combined with 99mtechnetium-labeled sulphur colloid (Tc99m) or indocyanine green (ICG) is widely used for sentinel lymph node biopsy (SLNB) of early-stage breast cancer in developing countries and regions. However, studies investigating the effectiveness of MB combined with another tracer have produced heterogeneous results. The purpose of this network meta-analysis (NMA) was to evaluate the detection rate of MB alone, MB + Tc99m, and MB + ICG, and to examine the differences between the 3 methods.

Methods

We conducted a comprehensive electronic literature search on the PubMed, Embase, Web of Science, CNKI, and Wanfang Data databases from inception to October 2021. The meta-analysis included 7,498 patients in 49 studies. The risk of bias for each study was independently assessed as low, moderate, or high using criteria adapted from the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Fixed- and random-effects models were used to calculate pooled estimates. Mixed-comparison analysis using random-effects models. We assessed statistical heterogeneity by I2 statistics and evaluated publication bias using Begg’s test.

Results

The identification rate (IR), false-negative rate (FNR), sensitivity (SEN), and accuracy rate (AR) using MB + Tc99m were 96%, 7%, 93%, and 96%, respectively; the IR, FNR, SEN, and AR using MB + ICG were 97%, 7%, 93%, and 97%, respectively. The NMA found that IR and AR between MB + ICG and MB + Tc99m was OR =1.37 (95% CI: 0.41–4.20) and OR =1.33 (95% CI: 0.56–3.32), respectively.

Discussion

Our results are similar to those of most previous studies, and meta-analysis showed that the MB + Tc99m or MB + ICG mapping methods can be used to obtain higher IR and lower FNR than MB alone. Our NMA showed no statistical significance between MB + Tc99m and MB + ICG with IR and AR. Both MB + Tc99m and MB + ICG can be used as effective mapping methods in SLNB of early-stage breast cancer to improve the detection rate.

Clinical application of indocyanine green fluorescence navigation technology to determine the safe margin of advanced oral squamous cell carcinoma

BACKGROUND

Advanced oral squamous cell carcinoma (OSCC) has large lesions and deep infiltration, and the control of safe surgical margins was difficult. If residual tumor remains after incomplete tumor resection, it can lead to local tumor recurrence or even distant metastasis. This study sought to investigate the clinical application of indocyanine green (ICG)-based near-infrared fluorescence (NIF) molecular imaging in the intraoperative detection of surgical margins of advanced OSCC.

METHODS

Twenty-nine patients with advanced OSCC treated at the First Ward of Oral and Maxillofacial Surgery, Nanjing Stomatological Hospital were divided into the ICG group and non-ICG group. In the ICG group, the tumors were removed with the assistance of ICG fluorescence navigation technology. In the non-ICG group, the tumors were removed with conventional methods, and the cutting-edge tissues of the two groups underwent frozen biopsies. The margin abnormality rates were calculated and compared.

RESULTS

Under the excitation of NIF in the ICG group, tumor fluorescence development was observable in all lesions, and the tumor boundary was clear. The abnormal rates of the incisional margin in the ICG group and non-ICG group were 0.78% and 6.25%, respectively (P<0.05).

CONCLUSIONS

ICG-mediated NIF imaging technology provides a new method for observing and completely resecting tumors under direct vision during operation, and finding residual tumors at the cutting edge in time. These results will inform the treatment of advanced OSCC.

Near-infrared fluorescent imaging with indocyanine green in rabbit and patient specimens of esophageal cancer

Background

We aimed to assess the possibility of detecting esophageal cancer after intravenous injection of indocyanine green (ICG) in preclinical and clinical models.

Methods

Forty-five rabbits were surgically implanted with VX2 tumors into the esophageal muscular layer 2 weeks before esophagectomy. The rabbits received intravenous injection of ICG at doses of 1, 2, or 5 mg/kg at 3, 6, 12, 24, or 48 h before surgical removal of esophagus. Twelve patients scheduled to undergo esophagectomy were also enrolled, and all received 2 mg/kg of ICG intravenously at 3, 6, 12, or 24 h before surgical removal of esophagus. The fluorescence intensity was measured in all resected specimens from the rabbits and patients using a near-infrared (NIR) fluorescence imaging system after surgery.

Results

Esophageal tumors were successfully established in all rabbits, and fluorescent signals were detected in all animal and patient specimens. Tumor-to-normal ratio (TNR) analysis showed that higher doses resulted in a greater TNR. Injection of at least 2 mg/kg of ICG was required for clear visualization of the tumor, and the TNR was highest at 12 h after injection. The TNR in patients was also highest at 12 h (P=0.0004), with 2 mg/kg of ICG. None of the patients had major complications following ICG injection.

Conclusions

NIR fluorescence imaging can be used to visualize esophageal cancer after systemic injection of ICG. ICG at 2 mg/kg at 12 h is optimal for tumor detection. However, since the clinical trials were conducted in a small number of patients, further studies are needed in larger populations.

Tumor-Background Ratio is an effective method to identify tumors and false-positive nodules in indocyanine-green navigation surgery for pediatric liver cancer

BACKGROUND

Indocyanine green (ICG) navigation surgery has been used for hepatoblastoma (HB) in children but the technique has been reported for using in other childhood liver cancers were rare. This article summarizes the application experience of ICG in HB and other childhood liver cancers in children and explores the role of fluorescence intensity measurement in identifying tumors.

METHODS

To summarize the clinical experience of children with liver cancer treated by ICG navigation surgery. The tumor and its surrounding tissue were photographed by near infrared during the operation. The fluorescence intensity of tumors, ICG (+) lesions and the normal liver was measured, and the Tumor-Background Ratio (TBR) was calculated.

RESULTS

A total of 11 children with liver cancer were injected intravenously with ICG 1 day before operation. With the help of ICG fluorescence navigation, there was no residual tumor at the surgical margin for all the children. Total fluorescence was seen in 2 cases, rim fluorescence in 2 cases, and partial fluorescence in 7 cases. 19 ICG false-positive nodules were found on the resection stump or residual liver tissue in 5 cases, and the TBR value of tumors was higher than that of false- positive nodules. 10 children have survived without disease.

CONCLUSION

ICG navigation surgery is safe and feasible for liver cancer in children, which can enhance the visualization of the tumor during operation and provide more information about the location and boundaries of the tumor. This technique also has limitations, which can be affected by chemotherapy, tumor location, ICG administration regimen, and equipment. TBR is an effective method to identify tumor and non-cancerous lesions.

Indocyanine Green to Assess Vascularity of Ileal Conduit Anastomosis During Pelvic Exenteration for Recurrent/Persistent Gynecological Cancer: A Pilot Study

Introduction

Pelvic exenteration performed for recurrent/persistent gynecological malignancies has been associated with urological short- and long-term morbidity due to altered vascularization of tissues for previous radiotherapy. The aims of the present study were to describe the use of intravenous indocyanine green (ICG) to assess vascularity of urinary diversion (UD) after pelvic exenteration for gynecologic cancers, to evaluate the feasibility and safety of this technique, and to assess the postoperative complications.

Methods

Prospective, observational, single-center, pilot study including consecutive patients undergoing anterior or total pelvic exenteration due to persistent/recurrent gynecologic cancers between August 2020 and March 2021 at Fondazione Policlinico Gemelli IRCCS, Rome, Italy. All patients underwent intravenous injection of 3–6 ml of ICG (1.25 mg/ml) once the UD was completed. A near-infrared camera was used to evaluate ICG perfusion of anastomoses (ileum–ileum, right and left ureter with small bowel, and colostomy or colorectal sides of anastomosis) a few seconds after ICG injection.

Results

Fifteen patients were included in the study. No patient reported adverse reactions to ICG injection. Only 3/15 patients (20.0%) had an optimal ICG perfusion in all anastomoses. The remaining 12 (80.0%) patients had at least one ICG deficit; the most common ICG deficit was on the left ureter: 3 (20.0%) vs. 1 (6.7%) patient had no ICG perfusion on the left vs. right ureter, respectively (p = 0.598). 8/15 (53.3%) and 6/15 (40.0%) patients experienced grade ≥3 30-day early and late postoperative complications, respectively. Of these, two patients had early and one had late postoperative complications directly related to poor perfusion of anastomosis (UD leak, ileum–ileum leak, and benign ureteric stricture); all these cases had a suboptimal intraoperative ICG perfusion.

Conclusion

The use of ICG to intraoperatively assess the anastomosis perfusion at time of pelvic exenteration for gynecologic malignancy is a feasible and safe technique. The different vascularization of anastomotic stumps may be related to anatomical sites and to previous radiation treatment. This approach could be in support of selecting patients at higher risk of complications who may need personalized follow-up.

Use of indocyanine green fluorescence guidance in redo ileocolic resection for Crohn's disease

AIM

Redo ileocolic resection in patients with Crohn's disease (CD) is associated with significant technical challenges that may be associated with high complication rates. The aim of this study was to evaluate the feasibility of near-infrared fluorescence angiography with indocyanine green (ICG), often used to evaluate blood supply to the anastomosis in CD patients undergoing repeat ileocolic resection.

METHOD

This study was a retrospective analysis of patients who underwent redo ileocolic resection using ICG bowel perfusion assessment between 2015 and 2021. Patients were matched and compared on a 1:2 basis with a control group undergoing the same procedure without perfusion assessment.

RESULTS

Twelve patients underwent redo ileocolic resection with ICG perfusion assessment (ICG group). These were compared with 24 patients who underwent the procedure without ICG (control group). Both groups were similar in demographics and operative characteristics including median operating time (255 vs. 255.5 min, p = 0.39) and conversion rate (22% vs. 36.8%, p = 0.68). Median estimated blood loss was significantly higher in the ICG group [150 (50-400) vs. 100 ml (20-125)]. Successful ICG perfusion assessment was seen in all patients in the ICG group and did not change management in any case. Overall postoperative complication rates were comparable between the groups (58.3% vs. 54.1%, p = 0.72). No anastomotic leaks occurred in the ICG group compared with one (1/24, 4.2%) in the control group (p = 0.99).

CONCLUSION

Fluorescence ICG perfusion assessment is feasible and safe in redo ileocolic resection in patients with CD. Larger studies are needed to evaluate whether this technique should be routinely used in these complex surgical interventions.

Targeted Near-Infrared Fluorescence Imaging With Iodized Indocyanine Green in Preoperative Pulmonary Localization: Comparative Efficacy, Safety, Patient Perception With Hook-Wire Localization

Background

Precise preoperative localization is of great importance to improve the success rate and reduce the operation time of VATS surgery. This study aimed to assess the efficacy, safety, patient perception between CT-guided indocyanine green (ICG) preoperative localization of lung nodule and hook-wire localization.

Methods

65 patients with 85 clinically suspicious pulmonary nodules underwent ICG preoperative localization in this study, and 92 patients with 95 nodules localized by conventional hook-wire served as controls. Both hook-wire localization and ICG injection were performed under CT guidance. Successful targeting rate, success rate in the operative field, incidence rate of complications and respiratory pain score were recorded and compared.

Results

The successful targeting rate for both groups is 100%, however, due to hook-wire dislodgement, the success rate in the VATS operation field of the hook-wire group (95.6%) is lower than that of the ICG group (100%), with no significant difference(p=0.056). The overall complication rate of the hook-wire group (37.0%) is significantly higher than the ICG group (35.4%) (p=0.038). The mean respiratory pain score of the hook-wire group is 3.70 ± 1.25, which is significantly higher than that of the ICG group (2.85 ± 1.05) (p<0.001).

Conclusions

ICG composed with contrast mixture are superior to the conventional hook-wire preoperative lung nodule localization procedure, with a lower complication rate, lower pain score, and relatively higher success rate. ICG is a promising alternative method for pulmonary nodule preoperative localization.

Application of an indocyanine green surgical fluorescence imaging system in sentinel lymph node biopsy of acral malignant melanoma

Background

Regional lymph node status is an independent influencing factor for the prognosis of acral malignant melanoma, and the accuracy of sentinel lymph node biopsy (SLNB) is directly related to the judgment of regional lymph node status. This study aimed to explore the application value of indocyanine green (ICG) surgical fluorescence imaging system in the SLNB of acral malignant melanoma.

Methods

A total of 34 patients with acral malignant melanoma were admitted to the Department of Burn and Plastic Surgery in Jiangsu Provincial People’s Hospital from January 2020 to March 2020. Among these patients, 22 required SLNB. ICG and methylene blue (MB) were combined to intraoperatively trace the sentinel lymph nodes (SLNs). The total number of SLNs detected during the operation was counted. We compared the number, detection rate, as well as the detection rate and false negative rate of positive SLNs of SLNs detected by ICG, MB, and ICG combined with MB.

Results

A total of 56 SLNs were detected in the 22 patients, among which 55 were detected by ICG (98%), 41 were detected by MB (71%), and 56 (100%) were detected by ICG combined with MB, and the average number of SLNs were 2.5, 1.64, and 2.55, respectively. A total of nine SLNs were detected, of which nine were detected by ICG (100%), seven by MB (78%), and nine by ICG combined with MB (100%). Patients with negative SLNs had no recurrence at the 6-month follow-up.

Conclusions

Compared with MB, the ICG fluorescent imaging system can improve the detection rate of SLNs in patients with acral malignant melanoma. Also, ICG combined with MB was superior to ICG alone.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

A pilot study of near-infrared fluorescence guided surgery for primary tumor localization and lymph node mapping in colorectal cancer

Background

This pilot study aimed to evaluate the feasibility of near-infrared fluorescence imaging for primary tumor localization, lymph node mapping, and metastatic lymph node detection in colorectal cancer (CRC) using indocyanine green (ICG).

Methods

A total of 11 patients with CRC were prospectively enrolled. ICG (25 mg dissolved in 30 mL sterile water) was intravenously injected preoperatively, and the fluorescence intensity of the primary tumor, lymph nodes, and normal tissues, as well as the signal-to-background ratio (SBR) and contrast-to-noise ratio (CNR) were measured at 0.5, 1, 2, 4, and 24 h after ICG injection.

Results

The primary tumor could be located intraoperatively, and the tumor boundary was clear at 2–4 h. There was good contrast in the fluorescence intensity between tumor and normal tissues (SBR =2.11±0.36, CNR =8.74±0.35). The lymph node detection rate was 95% (38/40), and the SBR threshold of lymph nodes was 1.13.

Conclusions

This pilot study showed that primary tumor localization and lymph node mapping in CRC is feasible using near-infrared fluorescence imaging technology, though metastatic lymph nodes cannot be discriminated from benign ones. In addition, cancer nodules missed by both white light mode and palpation by the surgeon were unexpectedly found, resulting in a change in the surgical prognosis in 9.1% (1/11) of patients.

Assessment of liver injury using indocyanine green fluorescence imaging

Background

To investigate whether indocyanine green (ICG) fluorescence imaging can be used to evaluate chronic and acute liver injury induced by either a high-fat (HF) diet or carbon tetrachloride (CCl₄).

Methods

Sprague-Dawley (SD) rats were randomly divided into three groups: control group, HF diet-induced model group, and CCl₄-induced model group. The chronic and acute liver injury models were induced by a HF diet and intraperitoneal injection of CCl₄, respectively. After HF feeding, the liver index, levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) of the rats were determined. The livers were also collected to evaluate histopathology damage by hematoxylin and eosin (H&E) staining. After in vitro perfusion of the liver and ICG administration, the liver fluorescence intensity and corresponding spectral value were measured by using real-image guided system (REAL-IGS).

Results

After HF feeding, the liver index and levels of serum ALT and AST were significantly increased, and the livers of the rats showed severe histopathological changes. Compared with the control group, the hepatic lobes of the model rats exhibited incomplete green fluorescence, and the corresponding spectral value was markedly reduced.

Conclusions

ICG fluorescence imaging can be used to evaluate liver injury induced by either a HF diet or CCl₄.

The use of a uPAR-targeted probe for photothermal cancer therapy prolongs survival in a xenograft mouse model of glioblastoma

The development of tumor-targeted probes that can efficiently reach cancerous tissue is an important focus of preclinical research. Photothermal cancer therapy (PTT) relies on light-absorbing molecules, which are directed towards tumor tissue and irradiated with an external source of light. This light is transformed into heat, causing localized hyperthermia and tumor death. The fluorescent probe indocyanine green (ICG) is already used as an imaging agent both preclinically and in clinical settings, but its use for PTT is yet to be fully exploited due to its short retention time and non-specific tumor targeting. Therefore, increasing ICG tumor uptake is necessary to improve treatment outcome. The urokinase-type plasminogen activator receptor, uPAR, is overexpressed in multiple tumor types. ICG-Glu-Glu-AE105, consisting of the uPAR-targeting peptide AE105 conjugated to ICG, has shown great potential for fluorescence-guided surgery. In this study, ICG-Glu-Glu-AE105 was evaluated as photothermal agent in a subcutaneous mouse model of human glioblastoma. We observed that the photothermal abilities of ICG-Glu-Glu-AE105 triggered high temperatures in the tumor during PTT, leading to tumor death and prolonged survival. This confirms the potential of ICG-Glu-Glu-AE105 as photothermal agent and indicates that it could be used as an add-on to the application of the probe for fluorescence-guided surgery.

Intraoperative assessment of ureter perfusion after revascularization of transplanted kidneys using intravenous indocyanine green fluorescence imaging

Background

Kidney transplantation is the most valuable renal replacement therapy. One of the most common urologic complications following kidney transplantation is ureter anastomosis leakage, which leads to high morbidity along with kidney graft loss. We hypothesized that indocyanine green (ICG) fluorescence videography can assess ureter perfusion after revascularization of transplanted kidneys.

Methods

We conducted a prospective cross-sectional study in end-stage renal disease patients who underwent deceased donor kidney transplantation at Ramathibodi Hospital from September 2019 to January 2020. The segments of transplanted ureters were categorized as having good or poor perfusion based on the percentage from ICG fluorescence videography images. Then the results from ICG fluorescence videography were compared with histopathology which is considered the gold standard.

Results

Thirty-one sections of dissected ureters were evaluated from 10 patients. Compared with pathological diagnosis of ureteral ischemia, ICG videography had sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive likelihood ratio of 100%, 92.6%, 66.7%, 100%, and 14, respectively. Accuracy was 93.6%. The area under the curve of ICG fluorescence videography was 0.96. The average ureter length that maintained good perfusion was 14 cm from the ureteropelvic junction. Adverse events from ICG were not observed in this study.

Conclusions

We conclude that ICG fluorescence videography is beneficial for detection of early ureteral ischemia in kidney transplantation patients, with negligible adverse events. However, further studies with larger numbers of patients are necessary to confirm our results and clinical outcomes regarding complication rates.

Near-infrared laparoscopy with indocyanine green for axillary sentinel lymph node biopsy in early breast cancer: preliminary experience of a single unit

Background

A sentinel lymph node biopsy (SLNB) is a routine procedure for axillary staging in cN0 breast cancer (BC) patients. Indocyanine green (ICG) fluorescence can detect sentinel lymph nodes with higher sensitivity than carbon nanoparticle suspension (CNS). The present study investigated the availability and benefits of a near-infrared (NIR) laparoscopy-assisted SLNB using ICG and carbon nanoparticle suspension as tracers.

Methods

Forty patients with invasive BC, who had clinically negative axillary lymph nodes, participated in this observational study. ICG and CNS tracers were injected into the periareolar region simultaneously or sequentially. In the endoscopy-assisted group (n=20), the patients were given NIR laparoscopic SLNB based on ICG fluorescence and CNS staining. In the open-surgery group, the patients were given traditional SLNB using an open incision, and CNS tracers were injected into the same region as that in the endoscopy-assisted group.

Results

In the endoscopy-assisted group, lymphatic vessels and sentinel lymph nodes (SLNs) were successfully identified using ICG fluorescence imaging in most patients (19/20). The average number of SLNs removed was 2.85 (range, 1-4) in the endoscopy-assisted group, and 3.40 (range, 1-7) in the open-surgery group. There was no significant difference between the number of detected nodes (P=0.30). The patients who underwent endoscopy-assisted SLNBs had similar operating times, blood loss and hospital-stay lengths, but lower postoperative drainage volumes and higher satisfaction scores, as they did not have axillary incisions.

Conclusions

The NIR laparoscopy-assisted ICG-guided technique is a feasible and surgeon-friendly method for SLNB with good efficacy and acceptable safety. When combined with CNS, more SLNs can be detected and dissected.

Indocyanine green-labeled dasatinib as a new fluorescent probe for molecular imaging of gastrointestinal stromal tumors

BACKGROUND AND AIM

It is difficult to differentiate gastrointestinal stromal tumors (GISTs) from other subepithelial lesions under gastrointestinal endoscopy. Because most GISTs express tyrosine kinase receptor c-KIT, fluorescence-labeled c-KIT-specific tyrosine kinase inhibitors seem to be useful agents for molecular imaging of GIST. We aimed to develop a near-infrared fluorescent imaging technology for GIST targeting c-KIT using the novel fluorescent probe indocyanine green-labeled dasatinib (ICG-dasatinib) and to investigate the antitumor effect of ICG-dasatinib on GIST cells.

METHODS

Indocyanine green-labeled dasatinib was synthesized by labeling linker-induced dasatinib with ICG derivative 3-indocyanine-green-acyl-1,3-thiazolidine-2-thione. Human GIST cell lines GIST-T1 and GIST-882M were incubated with ICG-dasatinib and observed by fluorescent microscopy. GIST cells were incubated with ICG-dasatinib, unlabeled dasatinib, or imatinib, and cell viabilities were evaluated. Subcutaneous GIST model mice or orthotopic GIST model rats were intravenously injected with ICG-dasatinib and observed using an IVIS Spectrum.

RESULTS

Strong fluorescent signals of ICG-dasatinib were observed in both GIST cell lines in vitro. IC50 values for ICG-dasatinib, unlabeled dasatinib, and imatinib were 13.9, 1.17, and 16.2 nM in GIST-T1 and 26.6, 3.63, and 47.6 nM in GIST-882M cells, respectively. ICG-dasatinib accumulated in subcutaneous xenografts in mice. Fluorescent signals were also observed in liver and gallbladder, indicating biliary excretion; however, fluorescence intensity of tumors was significantly higher than that of intestine after washing. Strong fluorescent signals were observed in orthotopic xenografts through the covering normal mucosa in rats.

CONCLUSIONS

Indocyanine green-labeled dasatinib could visualize GIST cells and xenografted tumors. The antitumor effect of ICG-dasatinib was preserved to the same degree as imatinib.

Comparison between preoperative two-dimensional shear wave elastography and indocyanine green clearance test for prediction of post-hepatectomy liver failure

Background

Post-hepatectomy liver failure (PHLF) is one of the most serious complications and major causes of liver resection mortality. The purpose of this study is to investigate and compare the performance of preoperative two-dimensional shear wave elastography (2D-SWE) and the indocyanine green (ICG) clearance test for the prediction of PHLF.

Methods

A total of 172 consecutive patients who were undergoing major liver resection were prospectively identified. Patients were evaluated by preoperative 2D-SWE and ICG clearance test. According to the International Study Group of Liver Surgery (ISGLS) recommendations, No PHLF, PHLF A, PHLF B, and PHLF C group classifications were defined. The differences in liver stiffness value (LSV) and ICG retention rate at 15 minutes (ICGR15) among the different PHLF classifications were investigated. The performance of LSV and ICGR15 for diagnosing different classifications of PHLF was compared.

Results

PHLF occurred in 43 (25.0%) patients, and 24 (14.0%) patients were grade A, 14 (8.1%) were grade B, and 5 (2.9%) were grade C. Both LSV and ICGR15 of the PHLF C group were significantly higher than those of the No PHLF group (P=0.025, P=0.001, respectively). According to univariate and multivariate logistic regression analysis, LSV and ICGR15 were significantly related to PHLF (P=0.051, P=0.084, respectively). For diagnosis of ≥ PHLF A, ≥ PHLF B, and ≥ PHLF C, the areas under the receiver operating characteristic curve (AUCs) for 2D-SWE were 0.624 [95% confidence interval (CI): 0.536-0.712, P=0.015], 0.699 (95% CI: 0.576-0.821, P=0.005), and 0.831 (95% CI: 0.737-0.925, P=0.01), respectively. The AUCs of the ICG clearance test were 0.631 (95% CI: 0.542-0.721, P=0.01), 0.570 (95% CI: 0.436-0.704, P=0.32), and 0.717 (95% CI: 0.515-0.920, P=0.098), respectively. The AUC of LSV for the diagnosis of ≥ PHLF A was comparable to that of ICGR15 (P=0.17). The AUCs of LSV were significantly higher than those of ICGR15 for the diagnosis of ≥ PHLF B (P=0.002) and C (P=0.038).

Conclusions

2D-SWE demonstrates the potential to aid in the prediction of the severity of PHLF. Our findings also suggest that the performance of 2D-SWE is better than the ICG clearance test.

Preoperative computer tomography-guided indocyanine green injection is associated with successful localization of small pulmonary nodules

Background

Localization of small pulmonary nodules (SPNs) is challenging in minimally invasive pulmonary resection, and it is unknown whether computer tomography (CT) guided by indocyanine green (ICG) can provide accurate localization with minimal complications.

Methods

We performed a retrospective study of patients who underwent thoracoscopic resection of pulmonary nodules after CT-guided preoperative localization with ICG from May 2019 to May 2020. Demographics, procedural data, postoperative complications, and pathologic information, were collected, and an analysis of the accuracy and complications after surgery was conducted.

Results

In 471 patients, there was a total of 512 peripheral pulmonary nodules that were ≤2 cm in size. The average time for CT-guided percutaneous ICG injection for localization was 18 minutes, and 98.4% (504/512) of the nodules were successfully localized. The average size of the nodules was 9.1 mm, and the average depth from the pleural surface was 8.9 mm. Overall, 5.9% (28/471) of the patients had asymptomatic pneumothorax after localization, but none needed a tube thoracostomy. All the nodules were resected using video-assisted thoracoscopy technique.

Conclusions

Preoperative CT-guided transthoracic ICG injection is safe and feasible for localization of small lung nodules for minimally invasive pulmonary resection. This technique should be considered for preoperative CT-guided localization of small lung nodules.

Comparative study on the diagnostic value of intravenous/peritumoral injection of indocyanine green for metastatic lymph node location in patients with head and neck squamous cell carcinoma (HNSCC)

Background

Accurate assessment of regional lymph node (LN) status is essential for the treatment of head and neck squamous cell carcinoma (HNSCC) patients. In this study, we aimed to compare the difference between intravenous injection of indocyanine green (ICG) and peritumoral injection of ICG in the location of metastatic LNs.

Methods

Twenty-nine patients were enrolled in this study with 13 patients receiving intravenous injection of ICG and 16 patients receiving peritumoral injection of ICG. During the surgery, the fluorescence-positive LNs in vivo were sent to undergo frozen section after fluorescence intensity was recorded. After the cervical LN dissection, all LNs were sorted by region, and the fluorescence intensity was recorded before the LNs were sent for paraffin section.

Results

During the surgery, both intravenous or peritumoral injections with near-infrared (NIR) fluorescence imaging of ICG had their respective pros and cons in vivo, with the sensitivity and specificity being 62.5%/75% and 98.1%/89.1% respectively. After the surgery, both methods could reduce the pathological workload by preselecting the LNs at-risk in the premise of accurate assessing the cervical LN stage. However, intravenous ICG administration was more valuable in determining all types of LN status according to the fluorescence intensity [area under the curve (AUC): 0.91 vs. 0.78, P<0.001].

Conclusions

With the assistance of NIR fluorescence imaging using ICG, both administration methods could reduce the postoperative complication and the pathological workload, whereas the intravenous mode of ICG administration is superior in application value.

Sentinel lymph node in vulvar cancer

Lymph node removal as a part of surgical management is a standard of care in vulvar cancer patients. Due to patient morbidities and difficulties in treatment of inguinal healing after lymph nodes removal, lymphatic mapping has emerged as an increasingly popular option over the past few years. At this time several different techniques have been described and variety of different dyes were used. In addition, an important aspect of the use of the sentinel lymph node (SLN) technique is the removal of a limited number of lymph nodes, which allows more detailed pathological examination. Moreover, the interpretation of pathological ultra-staging of SLNs, which can identify low-volume metastases for which the clinical significance and the ideal management, remain uncertain. Despite differences in techniques and dyes used, this minimally invasive procedure is currently recommended as an alternative to full inguinofemoral lymph node dissection in selected cases by all major international societies. As for now SLN concept became a standard of care in vulvar cancer. This technique, though simple as a concept, requires a learning curve and should only be used in expert centers. This article provides a review on literature on SLN technique in vulvar cancer, current recommendations and future lines of investigation.