A feasibility study assessing quantitative indocyanine green angiographic predictors of reconstructive complications following nipple-sparing mastectomy

Introduction

Immediate post-mastectomy breast reconstruction offers benefits; however, complications can compromise outcomes. Intraoperative indocyanine green fluorescence angiography (ICGFA) may mitigate perfusion-related complications (PRC); however, its interpretation remains subjective. Here, we examine and develop methods for ICGFA quantification, including machine learning (ML) algorithms for predicting complications.

Methods

ICGFA video recordings of flap perfusion from a previous study of patients undergoing nipple-sparing mastectomy (NSM) with either immediate or staged immediate (delayed by a week due to perfusion insufficiency) reconstructions were analysed. Fluorescence intensity time series data were extracted, and perfusion parameters were interrogated for overall/regional associations with postoperative PRC. A naïve Bayes ML model was subsequently trained on a balanced data subset to predict PRC from the extracted meta-data.

Results

The analysable video dataset of 157 ICGFA featured females (average age 48 years) having oncological/risk-reducing NSM with either immediate (n=90) or staged immediate (n=26) reconstruction. For those delayed, peak brightness at initial ICGFA was lower (p<0.001) and significantly improved (both quicker-onset and brighter p=0.001) one week later. The overall PRC rate in reconstructed patients (n=116) was 11.2%, with such patients demonstrating significantly dimmer (overall, p=0.018, centrally, p=0.03, and medially, p=0.04) and slower-onset (p=0.039) fluorescent peaks with shallower slopes (p=0.012) than uncomplicated patients with ICGFA. Importantly, such relevant parameters were converted into a whole field of view heatmap potentially suitable for intraoperative display. ML predicted PRC with 84.6% sensitivity and 76.9% specificity.

Conclusion

Whole breast quantitative ICGFA assessment reveals statistical associations with PRC that are potentially exploitable via ML.

Near-infrared cholangiography with intragallbladder indocyanine green injection in minimally invasive cholecystectomy

Laparoscopic cholecystectomy (LC) remains one of the most commonly performed procedures in adult and paediatric populations. Despite the advances made in intraoperative biliary anatomy recognition, iatrogenic bile duct injuries during LC represent a fatal complication and consist an economic burden for healthcare systems. A series of methods have been proposed to prevent bile duct injury, among them the use of indocyanine green (ICG) fluorescence. The most commonly reported method of ICG injection is the intravenous administration, while literature is lacking studies investigating the direct intragallbladder ICG injection. This narrative mini-review aims to assess the potential applications, usefulness, and limitations of intragallbladder ICG fluorescence in LC. Authors screened the available international literature to identify the reports of intragallbladder ICG fluorescence imaging in minimally invasive cholecystectomy, as well as special issues regarding its use. Literature search retrieved four prospective cohort studies, three case-control studies, and one case report. In the three case-control studies selected, intragallbladder near-infrared cholangiography (NIRC) was compared with standard LC under white light, with intravenous administration of ICG for NIRC and with standard intraoperative cholangiography (IOC). In total, 133 patients reported in the literature have been administered intragallbladder ICG administration for biliary mapping during LC. Literature includes several reports of intragallbladder ICG administration, but a standardized technique has not been established yet. Published data suggest that NIRC with intragallbladder ICG injection is a promising method to achieve biliary mapping, overwhelming limitations of IOC including intervention and radiation exposure, as well as the high hepatic parenchyma signal and time interval needed in intravenous ICG fluorescence. Evidence-based guidelines on the role of intragallbladder ICG fluorescence in LC require the assessment of further studies and multicenter data collection into large registries.

Clinical application of indocyanine green fluorescence navigation technique in laparoscopic common bile duct exploration for complex hepatolithiasis

BACKGROUND

This study investigated the clinical application of the indocyanine green (ICG) fluorescence navigation technique in bile duct identification during laparoscopic common bile duct exploration (LCBDE) for complex hepatolithiasis.

METHODS

Eighty patients with complex hepatolithiasis were admitted to our department between January 2022 and June 2023 and randomly divided into control and observation groups. The control group underwent conventional LCBDE, while the observation group underwent LCBDE guided by ICG fluorescence.

RESULTS

Intraoperatively, the observation group had shorter operation and search times for the common bile duct (CBD), as well as reduced intraoperative blood loss and fewer complications, such as conversion to laparotomy and various injuries (gastroduodenal, colon, pancreatic, and vascular) than the control group, with statistical significance (P < 0.05). Postoperatively, the observation group had lower rates of postoperative bile leakage, abdominal infection, postoperative hemorrhage, and residual stone than the control group. Additionally, the observation group demonstrated significantly shorter times for resuming flatus, removal of the abdominal drainage tube, and hospitalization than the control group, with statistical significance (P < 0.05).

CONCLUSION

ICG fluorescence navigation technology effectively visualizes the bile duct, improves its identification rate, shortens the operation time, prevents biliary tract injury, and reduces the occurrence of complications.

Indocyanine green (ICG)-guided robotic resection for liver adenoma: combined technologies for precision surgery

HCA resection is crucial to prevent bleeding and malignant transformation. The aim of this study was to enhance the precision of tumor resection in hepatocellular adenoma (HCA) through the combination of intraoperative ultrasound (IOUS) and indocyanine green (ICG) fluorescence imaging. ICG was intravenously injected 24 h before surgery, enabling positive staining of HCA nodules. IOUS guided the parenchymal transection performed using the RoboLap approach. IOUS combined with ICG effectively demarcated lesions, allowing precision surgery while sparing healthy liver tissue. Intraoperative frozen examination further validated the potential of ICG to identify previously undetected lesions. The study showed promising advantages of ICG in HCA resections, potentially reducing the risk of recurrence and malignant transformation. The combined robotic and laparoscopic approach improved the feasibility of parenchymal-sparing surgery, offering a cautious assessment of HCA lesions.

Clinical and computational development of a patient-calibrated ICGFA bowel transection recommender

INTRODUCTION

Intraoperative indocyanine green fluorescence angiography (ICGFA) aims to reduce colorectal anastomotic complications. However, signal interpretation is inconsistent and confounded by patient physiology and system behaviours. Here, we demonstrate a proof of concept of a novel clinical and computational method for patient calibrated quantitative ICGFA (QICGFA) bowel transection recommendation.

METHODS

Patients undergoing elective colorectal resection had colonic ICGFA both immediately after operative commencement prior to any dissection and again, as usual, just before anastomotic construction. Video recordings of both ICGFA acquisitions were blindly quantified post hoc across selected colonic regions of interest (ROIs) using tracking-quantification software and computationally compared with satisfactory perfusion assumed in second time-point ROIs, demonstrating 85% agreement with baseline ICGFA. ROI quantification outputs detailing projected perfusion sufficiency-insufficiency zones were compared to the actual surgeon-selected transection/anastomotic construction site for left/right-sided resections, respectively. Anastomotic outcomes were recorded, and tissue lactate was also measured in the devascularised colonic segment in a subgroup of patients. The novel perfusion zone projections were developed as full-screen recommendations via overlay heatmaps.

RESULTS

No patient suffered intra- or early postoperative anastomotic complications. Following computational development (n = 14) the software recommended zone (ROI) contained the expert surgical site of transection in almost all cases (Jaccard similarity index 0.91) of the nine patient validation series. Previously published ICGFA time-series milestone descriptors correlated moderately well, but lactate measurements did not. High resolution augmented reality heatmaps presenting recommendations from all pixels of the bowel ICGFA were generated for all cases.

CONCLUSIONS

By benchmarking to the patient's own baseline perfusion, this novel QICGFA method could allow the deployment of algorithmic personalised NIR bowel transection point recommendation in a way fitting existing clinical workflow.

A supramolecular colloidal system based on folate-conjugated β-cyclodextrin polymer and indocyanine green for enhanced tumor-targeted cell imaging in 2D culture and 3D tumor spheroids

Indocyanine green (ICG) is an FDA-approved medical diagnostic agent that is widely used as a near-infrared (NIR) fluorescent imaging molecular probe. However, ICG tends to aggregate to form dimers or H-aggregates in water and lacks physical and optical stability, which greatly decreases its absorbance and fluorescence intensity in various applications. Additionally, ICG has no tissue- or tumor-targeting properties, and its structure is not easy to modify, which has further limited its application in cancer diagnosis. In this study, we addressed these challenges by developing a supramolecular colloidal carrier system that targets tumor cells. To this end, we synthesized a water-soluble β-cyclodextrin (β-CD) polymer conjugated with folate (FA), denoted PCD-FA, which is capable of forming inclusion complexes with ICG in water through host-guest interactions between the β-CD moieties and ICG molecules. The inclusion complexes formed by PCD-FA and ICG, called ICG@PCD-FA, dispersed stably in solution as colloidal nanoparticles, greatly improving the physical and optical properties of ICG by preventing ICG dimer formation, where ICG appeared as monomers and even J-aggregates. This resulted in stronger and more stable absorption at a longer wavelength of 900 nm, which may allow for deeper tissue penetration and imaging with reduced interference from biological tissues' autofluorescence. Moreover, ICG@PCD-FA showed a targeting effect on folate receptor-positive (FR+) tumor cells, which specifically highlighted FR+ cells via NIR endoscopic imaging. Notably, ICG@PCD-FA further improved permeation and accumulation in FR+ 3D tumor spheroids. Therefore, this ICG@PCD-FA supramolecular colloidal system may have a great potential for use in tumor NIR imaging and diagnostic applications.

The preliminary analysis of lymphatic flow around the connective tissues surrounding SMA and SpA elucidates patients' oncological condition in borderline-resectable pancreatic cancer

BACKGROUND

In pancreatic ductal adenocarcinoma (PDAC), invasion of connective tissues surrounding major arteries is a crucial prognostic factor after radical resection. However, why the connective tissues invasion is associated with poor prognosis is not well understood.

MATERIALS AND METHODS

From 2018 to 2020, 25 patients receiving radical surgery for PDAC in our institute were enrolled. HyperEye Medical System (HEMS) was used to examine lymphatic flow from the connective tissues surrounding SMA and SpA and which lymph nodes ICG accumulated in was examined.

RESULTS

HEMS imaging revealed ICG was transported down to the paraaortic area of the abdominal aorta along SMA. In pancreatic head cancer, 9 paraaortic lymph nodes among 14 (64.3%) were ICG positive, higher positivity than LN#15 (25.0%) or LN#18 (50.0%), indicating lymphatic flow around the SMA was leading directly to the paraaortic lymph nodes. Similarly, in pancreatic body and tail cancer, the percentage of ICG-positive LN #16a2 was very high, as was that of #8a, although that of #7 was only 42.9%.

CONCLUSIONS

Our preliminary result indicated that the lymphatic flow along the connective tissues surrounding major arteries could be helpful in understanding metastasis and improving prognosis in BR-A pancreatic cancer.

Nucleus-targeting DNase I self-assembly delivery system guided by pirarubicin for programmed multi-drugs release and combined anticancer therapy

The cell nucleus serves as the pivotal command center of living cells, and delivering therapeutic agents directly into the nucleus can result in highly efficient anti-tumor eradication of cancer cells. However, nucleus-targeting drug delivery is very difficult due to the presence of numerous biological barriers. Here, three antitumor drugs (DNase I, ICG: indocyanine green, and THP: pirarubicin) were sequentially triggered protein self-assembly to produce a nucleus-targeting and programmed responsive multi-drugs delivery system (DIT). DIT consisted of uniform spherical particles with a size of 282 ± 7.7 nm. The acidic microenvironment of tumors and near-infrared light could successively trigger DIT for the programmed release of three drugs, enabling targeted delivery to the tumor. THP served as a nucleus-guiding molecule and a chemotherapy drug. Through THP-guided DIT, DNase I was successfully delivered to the nucleus of tumor cells and killed them by degrading their DNA. Tumor acidic microenvironment had the ability to induce DIT, leading to the aggregation of sufficient ICG in the tumor tissues. This provided an opportunity for the photothermal therapy of ICG. Hence, three drugs were cleverly combined using a simple method to achieve multi-drugs targeted delivery and highly effective combined anticancer therapy.

The Efficacy and Safety of an Indocyanine Green-Macroaggregated Albumin-Hyaluronic Acid Mixture (LuminoMark™) for Surgical Localization of Recurrent Thyroid Cancer

BACKGROUND

The recurrence of thyroid cancer poses challenges compounded by postoperative fibrosis and anatomic changes. By overcoming the limitations of current localizing dye techniques, indocyanine green-macroaggregated albumin-hyaluronic acid (ICG-MAA-HA) mixture dye promises improved localization. This study aimed to evaluate the efficacy and safety of the dye for recurrent thyroid cancer.

METHODS

The nine patients in this study underwent surgery and postoperative ultrasonography. The dye was injected into recurrent lesions in all the patients preoperatively. During surgery, the lesions were confirmed with an imaging system before and after excision. If the lesion was unidentifiable with the naked eye, surgical excision was performed under the corresponding fluorescent guide. Side effects related to the dye injection and completeness of the surgery were evaluated.

RESULTS

No side effects such as bleeding, skin tattooing, or pain during or after the dye injection were reported, and no discoloration occurred that interfered with the surgical field of view during surgery. In three cases (33.3 %), because it was difficult to localize metastatic lesions with the naked eye, the operation was successfully completed using an imaging system. The completeness of the surgical resection was confirmed by ultrasonography after an average of 5 months postoperatively.

CONCLUSION

The study found that ICG-MAA-HA dye effectively located metastatic and recurrent thyroid cancer and had favorable results in terms of minimal procedural side effects and potential for assisting the surgeon. A large-scale multi-institutional study is necessary to prove the clinical significance regarding patient survival and disease control.

Breast lymphedema following breast-conserving treatment for breast cancer: current status and future directions

PURPOSE

To examine the current evidence on breast lymphedema (BL) diagnosis and treatment after breast-conserving surgery, identify gaps in the literature, and propose future research directions.

METHODS

A comprehensive literature review was conducted using Ovid, PubMed, and Cochrane, including studies published between 2000 and 2023. References were reviewed manually for eligible studies. Inclusion criteria were as follows: patients who underwent breast conserving treatment (surgery ± radiation) for breast cancer, goals of the paper included analyzing or reviewing BL measurement with ultrasound or tissue dielectric constant, or BL treatment. Twenty-seven manuscripts were included in the review.

RESULTS

There is variation in incidence, time course, and risk factors for BL. Risk factors for BL included breast size, primary and axillary surgery extent, radiation, and chemotherapy but require further investigation. Diagnostic methods for BL currently rely on patient report and lack standardized criteria. Tissue dielectric constant (TDC) and ultrasound (US) emerged as promising ambulatory BL assessment tools; however, diagnostic thresholds and validation studies with ICG lymphography are needed to establish clinical utility. The evidence base for treatment of BL is weak, lacking high-quality studies.

CONCLUSION

The natural history of BL is not well defined. TDC and US show promise as ambulatory assessment tools for BL; however, further validation with lymphatic imaging is required. BL treatment is not established in the literature. Longitudinal, prospective studies including pre-radiation measurements and validating with lymphatic imaging are required. These data will inform screening, diagnostic criteria, and evidence-based treatment parameters for patients with BL after breast-conserving surgery and radiation.

Use of Indocyanine Green Near-Infrared Imaging for Sentinel Lymph Node Biopsy in Early Oral Squamous Cell Carcinoma: A Pilot Study

PURPOSE

The current established technique for sentinel lymph node (SLN) biopsy is preoperative injection of 99mtechnetium-labeled nanosized colloids (99mTc) followed by single photon emission computed tomography and standard computed tomography (SPECT/CT) with subsequent intraoperative gamma probe-guided excision of the SLN. It is however time and resource consuming, causes radiation exposure and morbidity for the patient as the injection is done in the awake patient. Recently near-infrared imaging with indocyanine green (ICG) gained importance in SLN biopsy as a faster and more convenient technique. The objective of our study was to investigate the feasibility of SLN biopsy using ICG-imaging in early oral squamous cell carcinoma (OSCC).

METHODS

Single-centre pilot study of five patients with early-stage OSCC. For all patients, both techniques (99mTc and ICG) were performed. We injected 99mTc preoperatively in the awake patient, followed by SPECT/CT imaging. Intraoperatively ICG was injected around the primary tumor. Then the neck incision was performed according to the SPECT/CT images and SLN were detected by using a gamma probe and near-infrared fluorescence imaging of the ICG-marked lymph nodes intraoperatively. The excised lymph nodes were sent to histopathological examination according to the SLN dissection protocol.

RESULTS

In all five patients sentinel lymph nodes were identified. A total of 7 SLN were identified after injection of 99mTc, imaging with SPECT/CT and intraoperative use of a gamma probe. All these SLN were fluorescent and visible with the ICG technique. In two patients, we could identify additional lymph nodes using the ICG technique. Pathological analysis demonstrated occult metastasis in two of the cases.

CONCLUSIONS

Our study shows that ICG-guided SLN biopsy is a feasible technique, especially in combination with conventional radioisotope method and may help for intraoperative localization of SLN. Validation studies with bigger patient cohorts are needed to prove our results.

Qualitative use of ICG angiography and lymphography in periorbital surgery

PURPOSE

Open imaging fluorescence devices have been utilized in surgical oncology, vascular and plastic surgery; however, the role of indocyanine green (ICG) in periorbital surgery and lymphatics has not been explored.

METHODS

A prospective, single-center diagnostic study was conducted from 2021 to 2022 utilizing ICG to assess both the periorbital vasculature and lymphatics. Fluorescence was captured with open-imaging fluorescent devices. For ICG angiography, a total of 5-10 mg of ICG was given intravenously at various time points to visualize intraoperative blood flow to eyelid flaps, vascular tumors, or extraocular muscles. For ICG lymphography, 0.03-0.06 mg of ICG was injected subcutaneously to visualize the periorbital and facial lymphatic drainage.

RESULTS

Twenty-two patients underwent ICG angiography. Periorbital vascular supply was seen in eyelid reconstructions (n = 8), anophthalmic reconstructions (n = 2), lacrimal gland tumors (n = 2), orbital venous malformations (n = 2), tumor metastasis (n = 1) and benign tumors (n = 1). The anterior ciliary arteries were visualized to the extraocular muscles in fracture repairs (n = 3) and muscle biopsies (n = 2). Ten patients underwent ICG lymphangiography highlighting the global periorbital lymphatic system.

CONCLUSION

ICG allows for visualization of the vasculature of extraocular muscles and tumors, assessing perfusion of flaps during reconstruction and the global periorbital lymphatic drainage pathways.

Near-infrared fluorescence-assisted superficial inguinal lymph-node excision for low-risk penile cancer

OBJECTIVE

Identification of superficial inguinal lymph nodes during low-risk penile cancer surgery using near-infrared (NIR) fluorescence to improve the accuracy of lymph-node dissection and reduce the incidence of missed micrometastases and complications.

METHODS

Thirty-two cases were selected, which were under the criteria of < T1, and no lymph-node metastasis was found with magnetic resonance imaging (MRI) detection. Two groups were randomly divided based on the fluorescence technique, the indocyanine green (ICG) group and the non-ICG group. In the ICG group, the ICG preparation was subcutaneously injected into the edge of the penile tumor 10 min before surgery, and the near-infrared fluorescence imager was used for observation. After the lymph nodes were visualized, the superficial inguinal lymph nodes were removed first, and then, the penis surgery was performed. The non-ICG group underwent superficial inguinal lymph-node dissection and penile surgery.

RESULTS

Among the 16 patients in the ICG group, we obtained 11 lymph-node specimens using grayscale values of images (4.13 ± 0.72 vs. 3.00 ± 0.82 P = 0.003) along with shorter postoperative healing time (7.31 ± 1.08 vs. 8.88 ± 2.43 P = 0.025), and less lymphatic leakage (0 vs. 5 P = 0.04) than the 16 patients in the non-ICG group. Out of 11, 3 lymph nodes that are excised were further grouped into fluorescent and non-fluorescent regions (G1/G2) and found to be metastasized.

CONCLUSION

Near-infrared fluorescence-assisted superficial inguinal lymph-node dissection in penile carcinoma is accurate and effective, and could reduce surgical complications.

Video-Based Indocyanine Green Fluorescence Applied to Robotic Duodenum-Preserving Pancreatic Head Resection

BACKGROUND

Duodenum-preserving pancreatic head resection (DPPHR) serves as a surgical intervention for managing benign and low-grade malignant neoplasms located in the head of the pancreas. This surgical approach enables the thorough excision of pancreatic head lesions, reducing the necessity for digestive tract reconstruction and enhancing the patient's quality of life.1 Performing a minimally invasive DPPHR is a complex surgical procedure, particularly when safeguarding the bile duct and the pancreaticoduodenal arterial arch. Robotic surgery is among the latest innovations in minimally invasive surgery and is widely used in many surgical specialties. It offers advantages such as rotatable surgical instruments, muscle tremor filters and up to 10-15 times three dimensional (3D) visual field,2 and achieves high flexibility and accuracy in surgical operations. Indocyanine green (ICG) fluorescence imaging technology is also applied to provide real-time intraoperative assessment of the biliary system and blood supply, which helps maintain the biliary system's integrity.3,4 We first report the complete procedure of ICG applied to the da Vinci robotic Xi system for preserving the DPPHR.

METHODS

A 48-year-old female patient was diagnosed with pancreatic duct stones, chronic pancreatitis, and pancreatogenic diabetes. Enhanced computed tomography (CT) scans revealed pancreatic head stones, pancreatic atrophy, scattered calcifications, and a dilated pancreatic duct. An attempt at endoscopic retrograde cholangiopancreatography (ERCP) treatment was abandoned during hospitalization due to unsuccessful catheterization. Following informed consent from the patient and her family, a robotic DPPHR was conducted utilizing ICG fluorescence imaging technology. Approximately 60 min before the surgery, 2 mg of ICG was injected via the peripheral vein. The individual was positioned in a reclined posture with the upper part of the bed raised to an angle of 30° and a leftward tilt of 15°. Upon entering the abdominal cavity, existing adhesions were meticulously separated and the gastrocolic ligament was opened to expose the pancreas. The lower part of the pancreas was separated and the superior mesenteric vein (SMV) was identified at the inferior boundary of the pancreatic neck. The pancreas was cut upward and the pancreatic duct was severed using scissors. Dissection of the lateral wall of the portal vein-SMV in the pancreatic head segment was performed. Meticulous dissection was carried out along the pancreatic tissue, retracting the uncinate process of the pancreas in an upward and rightward direction. During the dissection, caution was exercised to protect the anterior and posterior pancreaticoduodenal arterial arch. By using ICG fluorescence imaging, the path of the common bile duct was identified and verified. Caution was exercised to avoid injuring the bile duct. After isolating the CBD, the head and uncinate process of the pancreas was entirely excised. Under the fluorescence imaging mode, the wholeness of the CBD was scrutinized for any potential seepage of the contrast agent. Ultimately, a Roux-en-Y end-to-side pancreaticojejunostomy (duct to mucosa) was executed.

RESULTS

The surgery took 265 min and the estimated blood loss was about 150 mL. Without any postoperative complications, the patient was released from the hospital 13 days following the surgery. Postoperative pathology confirmed pancreatic duct stones and chronic pancreatitis. We have successfully performed four cases of robotic DPPHR using this technique, with only one patient experiencing a postoperative complication of pulmonary embolism. All patients were discharged successfully without any further complications.

CONCLUSIONS

Employing ICG fluorescence imaging in a robotic DPPHR has been demonstrated to be both secure and achievable. This technique potentially provides novel therapeutic perspectives, particularly for patients with ambiguous delineation between pancreatic and biliary ductal structures.

Engineered photonic near-infrared light activated photothermal theranostic nanovaccine induced targeted remodeling of tumor microenvironment

Tumor recurrence, which happens as a result of persisting tumor cells and minor lesions after treatments like surgery and chemotherapy, is a major problem in oncology. Herein, a strategy to combat this issue by utilize a theranostic nanovaccine composed of photonic HCuS. This nanovaccine aims to eradicate cancer cells and their traces while also preventing tumor recurrence via optimizing the photothermal immune impact. Successful membrane targeting allows for the introduction of new therapeutic agents into the tumor cells. Together with co-encapsulated Toll-Like Receptors (TLR7/8) agonist R848 for activating T cells and maturing DCs, the combined effects of HCuS and ICG function as photothermal agents that generate heat in the presence of NIR light. Photothermal-mediated immunotherapy with therapeutic modalities proved successful in killing tumor cells. By activating the immune system, this new photonic nanovaccine greatly increases immunogenic cell death (ICD), kills tumor cells, and prevents their recurrence.

Indocyanine Green-Labeled Platelets for Survival and Recovery Studies

Introduction

Before being implemented in daily clinical routine, new production strategies for platelet concentrates (PCs) must be validated for their efficacy. Besides in vitro testing, the establishment of new methods requires the labeling of platelets for in vivo studies of platelets' survival and recovery. Indocyanine green (ICG) is a Food and Drug Administration-approved near-infrared (NIR) fluorescent dye for diagnostic use in vivo, suitable for non-radioactive direct cell labeling of platelets.

Methods

Platelets from PCs in storage solutions with different plasma concentrations were labeled with ICG up to concentrations of 200 μm. Whole blood (WB) was used as an ex vivo matrix to monitor the labeling stability of ICG-labeled platelets. The impact of labeling processes was assessed by the quantification of CD62P expression and PAC-1 binding as platelet function markers. Platelet aggregation was analyzed by light transmission aggregometry. ICG-labeling efficiency and stability of platelets were determined by flow cytometry.

Results

Platelets from PCs could be successfully labeled with 10 μm ICG after 1 and 4 days of storage. The best labeling efficiency of 99.8% ± 0.1% (immediately after labeling) and 81% ± 6.2% (after 24 h incubation with WB) was achieved by plasma replacement by 100% platelet additive solution for the labeling process. Since the washing process slightly impaired platelet function, ICG labeling itself did not affect platelets. Immediately after the ICG-labeling process, plasma was re-added, resulting in a recovered platelet function.

Conclusion

We developed a Good Manufacturing Practice compatible protocol for ICG fluorescent platelet labeling suitable for survival and recovery studies in vivo as a non-radioactive labeling alternative.

Role of indocyanine green fluorescence imaging for evaluating blood supply in the gastric conduit via the substernal route after McKeown minimally invasive esophagectomy

BACKGROUND

Anastomotic leakage (AL) is a determining factor of morbidity and mortality after esophagectomy. Adequate perfusion of the gastric conduit is crucial for AL prevention. This study aimed to determine whether intraoperative angiography using indocyanine green (ICG) fluorescence improves the incidence of AL after McKeown minimally invasive esophagectomy (MIE) with gastric conduit via the substernal route (SR).

METHODS

This retrospective cohort study included 120 patients who underwent MIE with gastric conduit via SR for esophageal cancer between February 2019 and April 2023. Of 120 patients, 88 experienced intraoperative angiography using ICG (ICG group), and 32 patients experienced intraoperative angiography without ICG (no-ICG group). Baseline characteristics and operative outcomes, including AL as the main concern, were compared between the 2 groups. In addition, the outcomes among patients in the ICG group with different levels of fluorescence intensity were compared.

RESULTS

The ICG and no-ICG groups were comparable in baseline characteristics and operative outcomes. There was no significant difference between the 2 groups regarding the rate of AL (31.0% vs 37.5%; P = .505), median dates of AL (9 vs 9 days; P = .810), and severity of AL (88.9%, 11.11%, and 0.0% vs 66.7%, 16.7%, and 16.7% for grades I, II, and III, respectively; P = .074). Patients in the ICG group with lower intensity of ICG had higher rates of leakage (24.6%, 39.3%, and 100% in levels I, II, and III of ICG intensity, respectively; P = .04).

CONCLUSION

The use of ICG did not seem to reduce the rate of AL. However, abnormal intensity of ICG fluorescence was associated with a higher rate of AL, which implies a predictive potential.

Comparative Study of Indocyanine Green Fluorescence Imaging in Lung Cancer with Near-Infrared-I/II Windows

BACKGROUND

We compare the application of intravenous indocyanine green (ICG) fluorescence imaging in lung cancer with near-infrared-I (NIR-I) and near-infrared-II (NIR-II) windows.

METHODS

From March to December 2022, we enrolled patients who received an intravenous injection of ICG (5 mg/kg) 1 day before the planned lung cancer surgery. The lung cancer nodules were imaged by NIR-I/II fluorescence imaging systems, and the tumor-to-normal-tissue ratio (TNR) was calculated. In addition, the fluorescence intensity and signal-to-background ratio (SBR) of capillary glass tubes containing ICG covered with different thicknesses of lung tissue were measured by NIR-I/II fluorescence imaging systems.

RESULTS

In this study, 102 patients were enrolled, and the mean age was 59.9 ± 9.2 years. A total of 96 (94.1%) and 98 (96.1%) lung nodules were successfully imaged with NIR-I and NIR-II fluorescence, and the TNR of NIR-II was significantly higher than that of NIR-I (3.9 ± 1.3 versus 2.4 ± 0.6, P < 0.001). In multiple linear regression, solid nodules (P < 0.001) and squamous cell carcinoma (P < 0.001) were independent predictors of a higher TNR of NIR-I/II. When capillary glass tubes were covered with lung tissue whose thickness was more than 2 mm, the fluorescence intensity and the SBR of NIR-II were significantly higher than those of NIR-I.

CONCLUSIONS

We verified the feasibility of NIR-II fluorescence imaging in intravenous ICG lung cancer imaging for the first time. NIR-II fluorescence can improve the TNR and penetration depth of lung cancer with promising clinical prospects.

Fluorescence imaging for real-time detection of breast cancer tumors using IV injection of indocyanine green with non-conventional imaging: a systematic review of preclinical and clinical studies of perioperative imaging technologies

BACKGROUND

This review summarizes the available data on the effectiveness of indocyanine green fluorescence imaging (ICG-FI) for real-time detection of breast cancer (BC) tumors with perioperative imaging technologies.

METHODS

PubMed and Scopus databases were exhaustively searched for publications on the use of the real-time ICG-FI evaluation of BC tumors with non-conventional breast imaging technologies.

RESULTS

Twenty-three studies were included in this review. ICG-FI has been used for BC tumor identification in 12 orthotopic animal tumor experiences, 4 studies on animal assessment, and for 7 human clinical applications. The BC tumor-to-background ratio (TBR) was 1.1-8.5 in orthotopic tumor models and 1.4-3.9 in animal experiences. The detection of primary human BC tumors varied from 40% to 100%. The mean TBR reported for human BC varied from 2.1 to 3.7. In two studies evaluating BC surgical margins, good sensitivity (93.3% and 100%) and specificity (60% and 96%) have been reported, with a negative predictive value of ICG-FI to predict margin involvement intraoperatively of 100% in one study.

CONCLUSIONS

The use of ICG-FI as a guiding tool for the real-time identification of BC tumors and for the assessment of tumor boundaries is promising. There is great variability between the studies with regard to timing and dose. Further evidence is needed to assess whether ICG-guided BC surgery may be implemented as a standard of care.

Indocyanine green: The guide to safer and more effective surgery

In this editorial we comment on the article by Kalayarasan and co-workers published in the recent issue of the World Journal of Gastrointestinal Surgery. The authors present an interesting review on the use of indocyanine green fluorescence in different aspects of abdominal surgery. They also highlight future perspectives of the use of indocyanine green in mini-invasive surgery. Indocyanine green, used for fluorescence imaging, has been approved by the Food and Drug Administration and is safe for use in humans. It can be administered intravenously or intra-arterially. Since its advent, there have been several advancements in the applications of indocyanine green, especially in the surgical field, such as intraoperative mapping and biopsy of sentinel lymph node, measurement of hepatic function prior to resection, in neurosurgical cases to detect vascular anomalies, in cardiovascular cases for patency and assessment of vascular abnormalities, in predicting healing following amputations, in helping visualization of hepatobiliary anatomy and blood vessels, in reconstructive surgery, to assess flap viability and for the evaluation of tissue perfusion following major trauma and burns. For these reasons, the intraoperative use of indocyanine green has become common in a variety of surgical specialties and transplant surgery. Colorectal surgery has just lately begun to adopt this technique, particularly for perfusion visualization to prevent anastomotic leakage. The regular use of indocyanine green coupled with fluorescence angiography has recently been proposed as a feasible tool to help improve patient outcomes. Using the best available data, it has been shown that routine use of indocyanine green in colorectal surgery reduces the rates of anastomotic leak. The use of indocyanine green is proven to be safe, feasible, and effective in both elective and emergency scenarios. However, additional robust evidence from larger-scale, high-quality studies is essential before incorporating indocyanine green guided surgery into standard practice.

Fluorescence-guided thoracoscopic surgery for postoperative chylothorax: A technical note with video vignette

TECHNIQUE

The surgical management for high-output postoperative chylothorax typically necessitates ligation of the thoracic duct (TD) above the leak site and/or sealing the leak with a clip. However, pinpointing these structures during subsequent surgeries can be challenging due to their variable course and the presence of traumatized tissues surrounding the leak area. In response to this, we have developed a novel, fluorescence-guided technique that significantly enhances intraoperative identification of the leak point and the TD. This method was applied in the case of a 52-year-old man suffering from refractory chylothorax following a previous lung cancer surgery. This study documents the surgical procedure and includes a video vignette for a comprehensive understanding.

RESULTS

A bilateral inguinal lymph node injection of saline (10 mL), guided by ultrasound and containing 2.5 mg/mL indocyanine green (ICG), was administered 20 min prior to surgery. During thoracoscopic exploration, the leak point was precisely pinpointed in the right paratracheal area by transitioning from bright light to fluorescent mode. The TD was clearly identified, and upon ligation, there was no further leakage of fluorescent lymph, indicating a successful closure of the lymphatic structure. The surgery proceeded uneventfully, and the patient was able to resume oral intake on the third postoperative day. There was no evidence of recurring symptoms, leading to his discharge.

CONCLUSION

The intralymphatic injection of ICG offers a rapid visualization of the TD's anatomy and can effectively pinpoint the leak point, even amidst traumatized tissues. Moreover, it provides prompt feedback on the efficacy of ligation.

A Pilot Study for Biliary Atresia Diagnosis: Fluorescent Imaging of Indocyanine Green in Stool

BACKGROUND

Biliary atresia is the most common cause of obstructive jaundice in infants and conventional cholangiography is the current diagnostic gold standard. Fluorescent cholangiography with indocyanine green can enhance biliary tree visualization during surgery because it is exclusively excreted into the bile ducts and eventually into the intestine. Therefore, we hypothesized that indocyanine green presence in stool could confirm bile duct patency in infants.

METHODS

A prospective single center cohort study was performed on infants (age ≤ 12 months) with and without jaundice after obtaining IRB approval. Indocyanine green was administered intravenously (0.1 mg/kg). Soiled diapers collected post-injection were imaged for fluorescence.

RESULTS

After indocyanine green administration, fluorescence was detected in soiled diapers for control patients (n = 4, x = 14 h22 m post-injection) and jaundiced patients without biliary atresia (n = 11, x = 13 h28 m post-injection). For biliary atresia patients (n = 7), post-injection soiled diapers before and after Kasai portoenterostomy were collected. Fluorescence was not detected in stool from 6 of 7 biliary atresia patients. As a test, indocyanine green detection in stool was 97% accurate for assessing biliary patency.

CONCLUSION

Fluorescent Imaging for Indocyanine Green (FIInd Green) in stool is a fast and accurate approach to assess biliary patency non-invasively in infants.

LEVEL OF EVIDENCE

Level III.

Evaluating the effectiveness of dual dye combination of indocyanine green and carbon nanoparticles with parathyroid hormone test in preserving parathyroid gland during papillary thyroid cancer surgery: a single-center retrospective cohort study

Preserving the integrity of parathyroid glands is crucial in papillary thyroid cancer (PTC) surgery to avoid hypoparathyroidism. In recent years, two novel dyes, activated carbon nanoparticles (CNP) and indocyanine green (ICG), have been utilized to assist in parathyroid gland identification. However, the use of CNP or ICG alone can result in extravasation of dye or excessive fluorescence of non-parathyroid tissue, which can affect the accuracy of surgical outcomes by yielding false negative or false positive results. Therefore, it is important to further optimize the application of these two dyes in surgery. We analyzed case files of 124 PTC patients who underwent routine total or near-total thyroidectomy with bilateral lymph node dissection in the central region at the Affiliated People's Hospital of Ningbo University from January to November 2022. The patients were randomly divided into three groups based on the type of intraoperative dye used. The CNP group (n = 38) received an intra-thyroidal injection of CNP dye. The ICG group (n = 42) used the ICG near-infrared fluorescence endoscopy system to show parathyroid fluorescence. The group that received a combined approach of ICG and CNP (n = 44) leveraged the advantages of both methods that allow for positive development of ICG and negative development of CNP to identify and preserve the parathyroid gland during operation. The parathyroid hormone detection reagent (PTH test method) was employed to verify the highly suspected parathyroid tissue in all three groups. We analyzed intraoperative data pertaining to intraoperative parathyroid identification, misexcision, number of autotransplantation, and postoperative hypoparathyroidism among the three groups. Compared with the ICG group and the CNP group, the combined group demonstrated more prominent advantages in identifying average the number of lower parathyroid glands (1.93 ± 0.26, p = 0.015), reducing the average numberrate of misexcision (0.45 ± 0.5, p = 0.004), and reducing the incidence of postoperative temporary hypothyroidism (3/44, p = 0.015). The combined use of ICG and CNP dual-dye with PTH test method appears to be more effective in both identifying and protecting parathyroid glands during PTC surgery.

Clinicopathological factors associated with sentinel lymph node detection in non-small-cell lung cancer

BACKGROUND

Mapping of the pulmonary lymphatic system by near-infrared (NIR) fluorescence imaging might not always identify the first lymph node relay. The aim of this study was to determine the clinicopathologic factors allowing the identification of sentinel lymph nodes (SLNs) by NIR fluorescence imaging in thoracic surgery for non-small-cell lung cancer (NSCLC).

METHODS

We conducted a retrospective review of 92 patients treated for suspected or confirmed cN0 lung cancer with curative intent who underwent an intraoperative injection of indocyanine green (ICG) either by direct peritumoral injection or by endobronchial injection using electromagnetic navigational bronchoscopy (ENB). After exclusion of patients for technical failure, benign disease and metastasis, we analyzed the clinicopathologic findings of 65 patients treated for localized-stage NSCLC, comparing the group with identification of SLNs (SLN-positive group) with the group without identification of SLNs (SLN-negative group).

RESULTS

Forty-eight patients (73.8%) were SLN-positive. Patients with SLN positivity were more frequently female (50%) than the SLN-negative patients were (11.8%) (p = 0.006). The mean value of diffusing capacity for carbon monoxide (DLCO) was lower among the patients in the SLN-negative group (64.7% ± 16.7%) than the SLN-positive group (77.6% ± 17.2%, p < 0.01). The ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FCV) was higher in the SLN-positive group (69.0% vs. 60.8%, p = 0.02). Patients who were SLN-negative were characterized by a severe degree of emphysema (p = 0.003). There was no significant difference in pathologic characteristics. On univariate analyses, age, female sex, DLCO, FEV1/FVC, degree of emphysema, and tumor size were significantly associated with SLN detection. On multivariate analysis, DLCO > 75% (HR = 4.92, 95% CI: 1.27-24.7; p = 0.03) and female sex (HR = 5.55, 95% CI: 1.25-39.33; p = 0.04) were independently associated with SLN detection.

CONCLUSIONS

At a time of resurgence in the use of the sentinel lymph node mapping technique in the field of thoracic surgery, this study enabled us to identify, using multivariate analysis, two predictive factors for success: DLCO > 75% and female sex. Larger datasets are needed to confirm our results.

A combined experimental and DFT study of metal core/indocyanine green shell hybrid nanoparticles

Indocyanine green (ICG) is the FDA-approved fluorescent dye used for in vivo medical imaging, diagnostics, and photothermal therapy. However, this dye is easily degradable in the human vascular system, and therefore its stabilization is preferable. In this work, ICG molecules were stabilized by their adsorption on the surface of the L-methionine-capped Ag and Au nanoparticles (Ag and Au @LM NPs) in aqueous colloidal dispersions. The result is the formation of hybrid metal core/ICG shell NPs in colloidal dispersions. Additionally, colloidal dispersions were stabilized, indicating a double effect of ICG adsorption. The obtained hybrid NPs were studied experimentally (UV-Vis spectrophotometry, HRTEM, DLS, FTIR) and theoretically (DFT calculations). HRTEM revealed that the interplanar spacing between adjacent planes of NPs decreases after the dye adsorption. The results obtained from the DFT study confirmed the formation of a covalent bond between the oxygen from ICG dye SO3- group and metal NPs. Considering the characteristics of both components of the NPs/ICG hybrid system, the authors assume that this hybrid system can exhibit the synergistic effect that could lead to more successful theranostic treatment of cancer in nanomedicine.

Utility of Indocyanine Green for Sentinel Lymph Node Biopsy in Pediatric Sarcoma and Melanoma

BACKGROUND

Indocyanine green (ICG) is a fluorescent dye with increasing use for adult sentinel lymph node biopsy (SLNB). The utility of ICG in pediatric oncology remains understudied. We aim to describe our experience using ICG for SLNB in pediatrics versus standard blue dye.

METHODS

A retrospective review of pediatric patients with melanoma or sarcoma who underwent SLNB with technetium plus ICG or blue dye from 2014 to 2023 at a large academic children's hospital was conducted.

RESULTS

Twenty-four patients were included; 58.3% were male with median age 13 years (range 4-21 years). The majority had a melanocytic tumor (91.7%) and 8.3% had sarcoma. All patients received technetium with concomitant blue dye (62.5%) or ICG (37.5%). ICG more reliably identified radioactive SLNs, compared to blue dye (mean 100% vs 78.3 ± 8.3%, p = 0.03). There was no significant difference in median operative time (ICG 82 min [68-203] vs blue dye 93 min [78-105], p = 0.84). Seven patients had positive SLNs (29.2%), with recurrence in 2 patients (8.3%) and 1 death (4.2%). There were no adverse events.

CONCLUSION

ICG-directed SLNB in children is a safe and effective alternative to blue dye. Use of ICG did not add to operative time, and more often identified sentinel nodes versus blue dye.

TYPE OF STUDY

Original Research Article, Retrospective Comparative Study.

LEVEL OF EVIDENCE

III.

Blood flow evaluation of reconstructed gastric tube in esophageal surgery using near-infrared imaging and retrospective time-intensity curve analysis

PURPOSE

Near-infrared fluorescence imaging using indocyanine green (ICG-NIFI) can visualize a blood flow in reconstructed gastric tube; however, it depends on surgeon's visual assessment. The aim of this study was to re-analyze the ICG-NIFI data by an evaluator independent from the surgeon and feasibility of creating the time-intensity curve (TIC).

METHODS

We retrospectively reviewed 97 patients who underwent esophageal surgery with gastric tube reconstruction between January 2017 and November 2022. From the stored ICG videos, fluorescence intensity was examined in the four regions of interest (ROIs), which was set around the planned anastomosis site on the elevated gastric tube. After creation the TICs using the OpenCV library, we measured the intensity starting point and time constant and assessed the correlation between the anastomotic leakage.

RESULTS

Postoperative leakage occurred for 12 patients. The leakage group had significantly lack of blood flow continuity between the right and left gastroepiploic arteries (75.0% vs. 22.4%; P < 0.001) and tended to have slower ICG visualization time assessed by the surgeon's eyes (40 vs. 32 s; P = 0.066). TIC could create in 65 cases. Intensity starting point at all ROIs was faster than the surgeon's assessment. The leakage group tended to have slower intensity starting point at ROI 3 compared to those in the non-leakage group (22.5 vs. 19.0 s; P = 0.087).

CONCLUSION

A TIC analysis of ICG-NIFI by an independent evaluator was able to quantify the fluorescence intensity changes that the surgeon had visually determined.

Robot assisted vaginal natural orifice transluminal endoscopic surgery for frozen pelvis

OBJECTIVE

To show feasibility and technique used to perform a total hysterectomy, bilateral salpingectomy, endometriosis resection, and ovarian reconstruction in a patient with a frozen pelvis secondary to a history of ruptured tubo-ovarian abscess.

DESIGN

Narrated step-by-step video demonstration.

SETTING

Single academic institution INTERVENTIONS: In patients with a history of multiple abdominal surgeries, abdominal mesh, or in the case of this patient, a history of ruptured tubo-ovarian abscess, a vaginal approach may offer a safer approach. Immediate access to the uterine pedicles through the vagina bypasses the need for extensive enterolysis and adhesiolysis through the abdomen. With the use of indocyanine green injected into bilateral ureters we show the benefits of immediate identification allowing for safer and more efficient dissection. We highlight rotational uterine maneuvers to aid in rectosigmoid to posterior-uterus dissection in limited space due to dense pelvic adhesions. Lastly, we underline the importance of ovarian reconstruction and oophoropexy in any ovarian surgery to allow for easier ovarian identification in future surgeries to possibly reduce the risks of ovarian remnant syndrome.

CONCLUSION

This video highlights the feasibility and strategies used to perform robot assisted vaginal natural orifice transluminal endoscopic surgery on a patient with a frozen pelvis.

Engineered macrophage-derived cellular vesicles for NIR-II fluorescence imaging-guided precise cancer photo-immunotherapy

Significant progress has been made in cancer immunotherapy; however, challenges such as interpatient variability, limited treatment response, and severe side effects persist. Although nanoimmunotherapy has emerged as a promising approach, the construction of precise and efficient nanosystems remain formidable challenges. Herein, a multifunctional nanoplatform was developed using macrophage-derived cellular vesicles (MCVs) for NIR-II imaging-guided precise cancer photo-immunotherapy. MCVs exhibited excellent tumor targeting and TAMs re-education effects, serving as both delivery carriers and therapeutic agents. Through amide bond, indocyanine green (ICG) was conjugated to the surface of MCVs, enabling in vivo tracking of MCVs distribution. Notably, ICG exhibited dual functionality as a NIR-II fluorescent agent and possessed photodynamic and photothermal effects, enabling the conversion of light energy into chemical or heat energy to eliminate tumor cells. This precision phototherapy triggered immunogenic cell death (ICD) of tumor, thereby activating the anti-tumor immune response. Additionally, MCVs loaded with R848, a toll-like receptor agonist, augmented the ICD-induced anti-tumor immunity. Animal experiments confirmed that MCVs-mediated photoimmunotherapy promoted T cell infiltration, inhibited tumor growth, and improved survival rates. In conclusion, we have developed a promising precision immunotherapy strategy capable of enhancing the immune response while mitigating off-target effects. These findings offer encouraging prospects for clinical translation.

Case Report of Indocyanine Green Endoscopy for Intrasellar Pituitary Adenoma Resection

Indocyanine green (ICG) angiography has become an established technology in many surgical fields, as well as in neurosurgery with the first application of microscope-integrated indocyanine angiography, which dates to 2003.1 More recently we observed the integration of ICG into endoscopic visualization (e-ICG), which resulted in different applications during the endoscopic endonasal approach ranging from evaluation of intranasal flap perfusion to differentiation of pituitary neuroendocrine tumors from normal gland or even as a predictive factor of postoperative visual function after expanded approaches.2-8 A 49-year-old woman was admitted to our hospital after a 1-year history of amenorrhea and radiologic finding of an intrasellar lesion. The clinical picture was compatible with a nonfunctioning pituitary neuroendocrine tumor, and the mass was completely removed by means of an endoscopic endonasal approach with intraoperative use of e-ICG (Video 1). A 25 mg intravenous bolus of ICG was injected immediately after completion of the sphenoid phase of the approach. ICG was visualized with a dedicated ICG-integrated endoscope coupled to an IMAGE1 S camera system set on Chroma enhancement mode. Near-infrared excitation of fluorescence (780-820 nm) was obtained using a D-light P Cold Light Fountain. At follow-up, the patient experienced resolution of her symptoms, without residues or relapses on control magnetic resonance. This case sheds light on some possible applications and advantages of e-ICG, including visualization of internal carotid arteries before the sellar opening, individuation of the pituitary gland, its distinction from the adenomatous tissue, and the possible evaluation of its degree of compression.

Impact of standardising indocyanine green fluorescence angiography technique for visual and quantitative interpretation on interuser variability in colorectal surgery

AIM/BACKGROUND

Intra-operative colonic perfusion assessment via indocyanine green fluorescence angiography (ICGFA) aims to address malperfusion-related anastomotic complications; however, its interpretation suffers interuser variability (IUV), especially early in ICGFA experience. This work assesses the impact of a protocol developed for both operator-based judgement and computational development on interpretation consistency, focusing on senior surgeons yet to start using ICGFA.

METHODS

Experienced and junior gastrointestinal surgeons were invited to complete an ICGFA-experience questionnaire. They subsequently interpreted nine operative ICGFA videos regarding perfusion sufficiency of a surgically prepared distal colon during laparoscopic anterior resection by indicating their preferred site of proximal transection using an online annotation platform (mindstamp.com). Six ICGFA videos had been prepared with a clinical standardisation protocol controlling camera and patient positioning of which three each had monochrome near infrared (NIR) and overlay display. Three others were non-standardised controls with synchronous NIR and overlay picture-in-picture display. Differences in transection level between different cohorts were assessed for intraclass correlation coefficient (ICC) via ImageJ and IBM SPSS.

RESULTS

58 clinicians (12 ICGFA experts, 46 ICGFA inexperienced of whom 23 were either finished or within one year of finishing training and 23 were junior trainees) participated as per power calculations. 63% felt that ICGFA should be routinely deployed with 57% believing interpretative competence requires 11-50 cases. Transection level concordance was generally good (ICC = 0.869) across all videos and levels of expertise (0.833-0.915). However, poor agreement was evident with the standardised protocol videos for overlay presentation (0.208-0.345). Similarly, poor agreement was seen for the monochrome display (0.392-0.517), except for those who were trained but ICG inexperienced (0.877) although even here agreement was less than with unstandardised videos (0.943).

CONCLUSION

Colorectal ICGFA acquisition and display standardisation impacts IUV with this specific protocol tending to diminish surgeon interpretation consistency. ICGFA video recording for computational development may require dedicated protocols.

Color enhancement and achromatization to increase the visibility of indocyanine green-stained internal limiting membrane during digitally assisted vitreoretinal surgery

PURPOSE

To investigate the impact of using digital assisted vitrectomy (DAV) for color enhancement in color channel and achromatization in color profile on the visibility of indocyanine green (ICG)-stained internal limiting membrane (ILM).

STUDY DESIGN

Retrospective observational study.

METHODS

Twenty eyes from 20 patients (7 men, 13 women) who underwent 27-gauge pars plana vitrectomy for epiretinal membrane removal were included. The presettings of five different imaging modes of the NGENUITY® 3D visualization system (Alcon laboratories, Inc.), were adjusted, and intraoperative images of ILM removal were captured under each presetting. The color contrast ratios (CCR) between the ICG-stained ILM area and peeled ILM area were compared across presettings objectively. Subjective visibility of ILM in each patient for different presettings was ranked using a Likert scale and evaluated by five examiners. Data on sex, age, preoperative and postoperative best-corrected visual acuity (BCVA), preoperative and postoperative intraocular pressure (IOP), and postoperative complications were analyzed.

RESULTS

Compared to other presettings the best CCR was achieved by adjusting the color channel to enhance red and by modifying the color profile to create a monochrome image (P<0.01). The same presetting resulted in a highest subjective visibility (P<0.01). Mean preoperative BCVA and 6-month postoperative BCVA (logMAR) were 0.11±0.18 and 0.05±0.19, respectively (p=0.24). Mean preoperative IOP and 6-month postoperative IOP were 13.8±2.8 mmHg and 13.3±3.4 mmHg, respectively (p=0.51). No apparent intra- and post-operative complications were observed.

CONCLUSION

Color enhancement and achromatization using DAV may offer potential advantages to enhance the visibility of ICG-stained ILM.

Surgical considerations and techniques using intraoperative indocyanine green angiography for ethmoidal dural arteriovenous fistula

OBJECTIVE

This study aims to investigate the efficacy of microsurgery with intraoperative indocyanine green (ICG) angiography as a treatment approach for ethmoidal dural arteriovenous fistula (DAVF).

METHODS

Between January 2010 and July 2021, our institution encountered a total of eight cases of ethmoidal DAVF. In each of these cases, microsurgical treatment was undertaken utilizing a bilateral sub-frontal interhemispheric approach, with the aid of intraoperative ICG angiography.

RESULTS

ICG angiography identified bilateral venous drainage with single dominance in four cases (50%) of ethmoidal DAVF, a finding that eluded detection during preoperative transfemoral cerebral angiography (TFCA). The application of microsurgical treatment, in conjunction with intraoperative ICG angiography, resulted in consistently positive clinical outcomes for all patients, as evaluated using the Glasgow Outcome Scale (GOS) at the 6-month postoperative follow-up assessment; six patients showed GOS score of 5, while the remaining two patients attained a GOS score of 4.

CONCLUSIONS

The use of intraoperative ICG angiography enabled accurate identification of both dominant and non-dominant venous drainage patterns, ensuring complete disconnection of the fistula and reducing the risk of recurrence.

Anatomical Distribution of Sentinel Lymph Nodes Harvested by Retroperitoneal vNOTES in 34 Consecutive Patients With Early-Stage Endometrial Cancer: Analysis of 124 Lymph Nodes

STUDY OBJECTIVE

To determine the anatomical distribution of sentinel lymph nodes (SLNs), the overall, unilateral, and bilateral detection rates, and the bilateral SLN concordance in patients with endometrial cancer (EC) mapped through a retroperitoneal transvaginal natural orifice transluminal endoscopic surgery (vNOTES) approach.

DESIGN

Prospective single-center observational study.

SETTING

Swiss teaching hospital.

PATIENTS

Patients with EC or endometrial complex atypical hyperplasia who had undergone surgical staging with SLN mapping by a retroperitoneal vNOTES approach between October 2021 and November 2023.

INTERVENTIONS

Patients were placed in a horizontal dorsal lithotomy position under general anesthesia, and indocyanine green (ICG) was injected into the cervix. Access to the retroperitoneal space was achieved through vaginal incisions. A 7 cm GelPoint V-Path Transvaginal Access Platform was used as a vNOTES port, and CO2 was insufflated to expand the retroperitoneal space. The pelvic retroperitoneal space was inspected for ICG uptake by lymph nodes. After identification, SLNs were removed and sent for definitive histological examination.

MEASUREMENT AND MAIN RESULTS

A total of 34 patients were included in this study; 33 (97.1%) had a successful procedure (unilateral or bilateral mapping), and 1 (2.9%) had failed mapping. A total of 124 SLNs were identified and removed. SLNs were observed in the obturator region (81.5%), the external iliac region (10.5%), the internal iliac region (4.8%), and the common iliac region (3.2%). Similar proportions were observed on both pelvic sides. No SLNs were detected in other regions. The SLN locations were symmetrical in 22/31 (71.0%) patients. SLNs were negatives in 120 cases (96.8%), while 2 lymph nodes (1.6%) presented isolated tumor cells, and 2 others (1.6%) presented macrometastases.

CONCLUSION

We report anatomical distributions and detection rates for SLNs mapped by retroperitoneal vNOTES. Our results suggest substantial differences in the localization of SLNs compared to those reported for laparoscopic mapping.

Don't forget emergency surgery! Lessons to learn from elective indocyanine green-guided gastrointestinal interventions

Fluorescence-based imaging has found application in several fields of elective surgery, but there is still a lack of evidence in the literature about its use in the emergency setting. Clinical trials have consistently shown that indocyanine green (ICG)-guided surgery can dramatically reduce the risk of postoperative complications, length of in-hospital stay and total healthcare costs in the elective setting. It is well-known that emergency surgery has a higher complication rate than its elective counterpart, therefore an impelling need for research studies to explore, validate and develop this issue has been highlighted. The present editorial aims to provide a critical overview of currently available applications and pitfalls of ICG fluorescence in abdominal emergencies. Furthermore, we evidenced how the experience of ICG-fluorescence in elective surgery might be of great help in implementing its use in acute situations. In the first paragraph we analyzed the tips and tricks of ICG-guided cancer surgery that might be exploited in acute cases. We then deepened the two most described topics in ICG-guided emergency surgery: Acute cholecystitis and intestinal ischemia, focusing on both the advantages and limitations of green-fluorescence application in these two fields. In emergency situations, ICG fluorescence demonstrates a promising role in preventing undue intestinal resections or their entity, facilitating the detection of intestinal ischemic zones, identifying biliary tree anatomy, reducing post-operative complications, and mitigating high mortality rates. The need to improve its application still exists, therefore we strongly believe that the elective and routinary use of the dye is the best way to acquire the necessary skills for emergency procedures.

Laparoscopic left hemihepatectomy guided by indocyanine green fluorescence: A cranial-dorsal approach

BACKGROUND

Advancements in laparoscopic technology and a deeper understanding of intrahepatic anatomy have led to the establishment of more precise laparoscopic hepatectomy (LH) techniques. The indocyanine green (ICG) fluorescence navigation technique has emerged as the most effective method for identifying hepatic regions, potentially overcoming the limitations of LH. While laparoscopic left hemihepatectomy (LLH) is a standardized procedure, there is a need for innovative strategies to enhance its outcomes.

AIM

To investigate a standardized cranial-dorsal strategy for LLH, focusing on important anatomical markers, surgical skills, and ICG staining methods.

METHODS

Thirty-seven patients who underwent ICG fluorescence-guided LLH at Qujing Second People's Hospital between January 2019 and February 2022 were retrospectively analyzed. The cranial-dorsal approach was performed which involves dissecting the left hepatic vein cephalad, isolating the Arantius ligament , exposing the middle hepatic vein, and dissecting the parenchyma from the dorsal to the foot in order to complete the anatomical LLH. The surgical methods, as well as intra- and post-surgical data, were recorded and analyzed. Our hospital's Medical Ethics Committee approved this study (Ethical review: 2022-019-01).

RESULTS

Intraoperative blood loss during LLH was 335.68 ± 99.869 mL and the rates of transfusion and conversion to laparotomy were 13.5% and 0%, respectively. The overall incidence of complications throughout the follow-up (median of 18 months; range 1-36 months) was 21.6%. No mortality or severe complications (level IV) were reported.

CONCLUSION

LLH has the potential to become a novel, standardized approach that can effectively, safely, and simply expose the middle hepatic vein and meet the requirements of precision surgery.

Indocyanine Green Angiography

The choroid plays an important role in the pathophysiology of the eye. Multimodal imaging offers different techniques to examine the choroid. Fundus fluorescein angiography offers limited visualization of the deep layers of the fundus due to the barrier property of the retinal pigment epithelium. Therefore, indocyanine green angiography (ICGA) is widely used in the angiographic examination of the choroidal structure. ICGA is an important component of multimodal imaging in the diagnosis and treatment of many degenerative, tumoral, and inflammatory diseases of the choroid and retina. This review presents the general characteristics of ICGA and a practical approach to its clinical use.

In vitro characterization of 3D culture-based differentiation of human liver stem cells

Introduction: The lack of functional hepatocytes poses a significant challenge for drug safety testing and therapeutic applications due to the inability of mature hepatocytes to expand and their tendency to lose functionality in vitro. Previous studies have demonstrated the potential of Human Liver Stem Cells (HLSCs) to differentiate into hepatocyte-like cells within an in vitro rotary cell culture system, guided by a combination of growth factors and molecules known to regulate hepatocyte maturation. In this study, we employed a matrix multi-assay approach to comprehensively characterize HLSC differentiation. Methods: We evaluated the expression of hepatic markers using qRT-PCR, immunofluorescence, and Western blot analysis. Additionally, we measured urea and FVIII secretion into the supernatant and developed an updated indocyanine green in vitro assay to assess hepatocyte functionality. Results: Molecular analyses of differentiated HLSC aggregates revealed significant upregulation of hepatic genes, including CYP450, urea cycle enzymes, and uptake transporters exclusively expressed on the sinusoidal side of mature hepatocytes, evident as early as 1 day post-differentiation. Interestingly, HLSCs transiently upregulated stem cell markers during differentiation, followed by downregulation after 7 days. Furthermore, differentiated aggregates demonstrated the ability to release urea and FVIII into the supernatant as early as the first 24 h, with accumulation over time. Discussion: These findings suggest that a 3D rotation culture system may facilitate rapid hepatic differentiation of HLSCs. Despite the limitations of this rotary culture system, its unique advantages hold promise for characterizing HLSC GMP batches for clinical applications.

Indocyanine green (ICG) fluorescence-enhanced applications in pediatric surgery

The breadth of pediatric surgical practice and variety of anatomic anomalies that characterize surgical disease in children and neonates require a unique level of operative mastery and versatility. Intraoperative navigation of small, complex, and often abnormal anatomy presents a particular challenge for pediatric surgeons. Clinical experience with fluorescent tissue dye, specifically indocyanine green (ICG), is quickly gaining widespread incorporation into adult surgical practice as a safe, non-toxic means of accurately visualizing tissue perfusion, lymphatic flow, and biliary anatomy to enhance operative speed, safety, and patient outcomes. Experience in pediatric surgery, however, remains limited. ICG-fluorescence guided surgery is poised to address the challenges of pediatric and neonatal operations for a growing breadth of surgical pathology. Fluorescent angiography has permitted intraoperative visualization of colorectal flap perfusion for complex pelvic reconstruction and anastomotic perfusion after esophageal atresia repair, while its hepatic absorption and biliary excretion has made it an excellent agent for delineating the dissection plane in the Kasai portoenterostomy and identifying both primary and metastatic hepatoblastoma lesions. Subcutaneous and intra-lymphatic ICG injection can identify iatrogenic chylous leaks and improved yields in sentinel lymph node biopsies. ICG-guided surgery holds promise for more widespread use in pediatric surgical conditions, and continued evaluation of efficacy will be necessary to better inform clinical practice and identify where to focus and develop this technical resource.

Autofluorescence of Parathyroid Glands: A Review of Methods of Parathyroid Gland Identification and Parathyroid Vascular Assessment

Postoperative hypoparathyroidism may cause significant patient morbidity and even mortality. Emerging technologies centered on autofluorescent properties of parathyroid glands when exposed to near-infrared light hold promise to improve surgical parathyroid gland identification and preservation. Two systems (probe-based and camera-based) are commercially available currently; however, neither system alone provides indication of vascular viability or postoperative parathyroid gland function. The administration of indocyanine green, when combined with near-infrared fluorescence imaging, enables subjective assessment of parathyroid gland perfusion. Additional technologies to assess parathyroid gland perfusion are being developed. The impact of these nascent technologies on relevant clinical outcomes is an area of active investigation.

Current applications of indocyanine green (ICG) in abdominal, gynecologic and urologic surgery: a meta-review and quality analysis with use of the AMSTAR 2 instrument

BACKGROUND

Indocyanine green (ICG) is an injectable fluorochrome that has recently gained popularity as a means of assisting intraoperative visualization during laparoscopic and robotic surgery. Many systematic reviews and meta-analyses have been published. We conducted a meta-review to synthesize the findings of these studies.

METHODS

PubMed and Embase were searched to identify systematic reviews and meta-analyses coping with the uses of ICG in abdominal operations, including Metabolic Bariatric Surgery, Cholecystectomy, Colorectal, Esophageal, Gastric, Hepato-Pancreato-Biliary, Obstetrics and Gynecology (OG), Pediatric Surgery, Surgical Oncology, Urology, (abdominal) Vascular Surgery, Adrenal and Splenic Surgery, and Interdisciplinary tasks, until September 2023. We submitted the retrieved meta-analyses to qualitative analysis based on the AMSTAR 2 instrument.

RESULTS

We identified 116 studies, 41 systematic reviews (SRs) and 75 meta-analyses (MAs), spanning 2013-2023. The most thoroughly investigated (sub)specialties were Colorectal (6 SRs, 25 MAs), OG (9 SRs, 15 MAs), and HPB (4 SRs, 12 MAs). Interestingly, there was high heterogeneity regarding the administered ICG doses, routes, and timing. The use of ICG offered a clear benefit regarding anastomotic leak prevention, particularly after colorectal and esophageal surgery. There was no clear benefit regarding sentinel node detection after OG. According to the AMSTAR 2 tool, most meta-analyses ranked as "critically low" (34.7%) or "low" (58.7%) quality. There were only five meta-analyses (6.7%) that qualified as "moderate" quality, whereas there were no "high" quality reviews.

CONCLUSIONS

Regardless of the abundance of pertinent literature and reviews, surgeons should be cautious when interpreting their results on ICG use in abdominal surgery. Future reviews should focus on ensuring methodological vigor; establishing clear protocols of ICG dose, route of administration, and timing; and improving reporting quality. Other sources of data (e.g., registries) and novel methods of data analysis (e.g., machine learning) might also contribute to an enhanced role of ICG as a decision-making tool in surgery.

The introduction of fluoroscopic surgery: A report of an initial trial case

INTRODUCTION

Switching from white light to fluorescence mode is necessary to confirm the fluorescence during fluorescence-guided surgery. This case report presents the use of a syringe pump to continuously inject indocyanine green (ICG), which enabled the vessels to be visualised and the operation to be performed without switching.

PRESENTATION OF CASE

An Asian male patient in his 40s underwent an interval appendectomy following conservative treatment for appendicitis. Laparoscopic surgery was performed using the VISIONSENSE® system. Diluted ICG (25 mg/15 mL) was intravenously administered at 1 mL/min. The appendiceal artery was visualised in light green, and the intensity of the visualisation was defined relative to the tissue surrounding the dissected appendiceal artery. The superior rectal artery and the vessels within the mesentery of the small intestine were confirmed to be continuously visualised throughout the surgery. Therefore, continuous ICG angiography made it possible to operate while keeping the appendiceal artery visible in this case.

DISCUSSION

ICG angiography enabled the operation to be performed with the appendiceal artery continuously visualised. This method was developed for use in cancer surgery; however, since operations of longer duration are speculated to require larger doses of ICG, we opted to introduce this method in an initial trial for appendectomy.

CONCLUSION

The fluoroscopic surgery using a syringe pump was feasible in this first case report without switching to white light mode.

Consensus conference statement on fluorescence-guided surgery (FGS) ESSO course on fluorescence-guided surgery

BACKGROUND

Fluorescence-guided surgery (FGS) has emerged as an innovative technique with promising applications in various surgical specialties. However, clinical implementation is hampered by limited availability of evidence-based reference work supporting the translation towards standard-of-care use in surgical practice. Therefore, we developed a consensus statement on current applications of FGS.

METHODS

During an international FGS course, participants anonymously voted on 36 statements. Consensus was defined as agreement ≥70% with participation grade of ≥80%. All participants of the questionnaire were stratified for user and handling experience within five domains of applicability (lymphatics & lymph node imaging; tissue perfusion; biliary anatomy and urinary tracts; tumor imaging in colorectal, HPB, and endocrine surgery, and quantification and (tumor-) targeted imaging). Results were pooled to determine consensus for each statement within the respective sections based on the degree of agreement.

RESULTS

In total 43/52 (81%) course participants were eligible as voting members for consensus, comprising the expert panel (n = 12) and trained users (n = 31). Consensus was achieved in 17 out of 36 (45%) statements with highest level of agreement for application of FGS in tissue perfusion and biliary/urinary tract visualization (71% and 67%, respectively) and lowest within the tumor imaging section (0%).

CONCLUSIONS

FGS is currently established for tissue perfusion and vital structure imaging. Lymphatics & lymph node imaging in breast cancer and melanoma are evolving, and tumor tissue imaging holds promise in early-phase trials. Quantification and (tumor-)targeted imaging are advancing toward clinical validation. Additional research is needed for tumor imaging due to a lack of consensus.

Evaluation of tissue blood supply during esophagectomy using fluorescent diagnostics and diffuse scattering spectroscopy in visible region

BACKGROUND

The success of the surgical treatment of a tumor or obstruction of the esophagus with subsequent anastomosis application depends on the level of blood supply to the stitched tissues. Intraoperative assessment of blood flow is widely used in medicine and can be used as a diagnostic method that affects the outcome of surgery and reduces the frequency of postoperative complications for the patient.

METHODS

In this work, the assessment of blood supply during esophageal resection operations was carried out using two techniques sequentially: fluorescent diagnostics with indocyanine green and measurement of hemoglobin oxygen saturation by diffuse scattering spectroscopy in the visible wavelength range. The first method was used to assess the integrity of the vascular network structure in the area of anastomosis and blood flow through the sutured tissues, the second one - for local assessment of hemoglobin oxygen saturation in the investigated area.

RESULTS

Conducted clinical study involved the participation of nine patients with malignant neoplasms (six cases) or esophageal obstruction (three cases). The presence of postoperative complications was compared with the measurement results. Anastomosis failure was observed in only one patient. According to the results of the study, with the use of the investigated method of assessing blood supply, there is a tendency towards a decrease in the frequency of anastomosis leaks (11.1 % compared with 21.4 %).

CONCLUSIONS

Therefore, fluorescent diagnostics with indocyanine green and measurement of hemoglobin oxygen saturation using diffuse scattering spectroscopy were affirmed as methods that allow increasing the safety of surgical procedures by assessing the risk of postoperative complications, including anastomosis failures.

Indocyanine green based photodynamic therapy for keloids: Fundamental investigation and clinical improvement

BACKGROUND

Keloid, a prevalent pathological skin lesion, presents significant challenges in terms of treatment efficacy. Photodynamic therapy (PDT), an increasingly popular adjuvant treatment, has shown significant potential in the management of various disorders, including cancer. However, the therapeutic potential of indocyanine green-mediated photodynamic therapy (ICG-PDT) for keloids has not yet been demonstrated.

METHODS

In this study, we divided the experimental groups into control group, Photothermal Therapy group, Photodynamic Therapy group, and Combined Therapy group. The in vitro investigation aimed to optimize the clinical application of PDT for keloid treatment by elucidating its underlying mechanism. Subsequently, on this basis, we endeavored to manage a clinical case of keloid by employing surgical intervention in conjunction with modified ICG-PDT.

RESULTS

Our investigation revealed an unexpected outcome that ICG-PDT maximally inhibited the cellular activity and migration of keloid fibroblasts only when photodynamic mechanism took effect. Additionally, the induction of autophagy and apoptosis, as well as the inhibition of collagen synthesis, were particularly evident in this experimental group. Furthermore, the above therapeutic effect could be achieved at remarkably low drug concentrations. Building upon the aforementioned experimental findings, we successfully optimized the treatment modality for the latest case and obtained a more favorable treatment outcome.

CONCLUSIONS

This study investigated the mechanism of ICG-PDT treatment and optimized the in vivo treatment regimen, demonstrating the significant therapeutic potential of ICG-PDT treatment in clinical keloid treatment.

Feasibility of novel intraoperative navigation for anatomical liver resection using real-time virtual sonography combined with indocyanine green fluorescent imaging technology

To analyze the feasibility and clinical effect of novel intraoperative navigation of real-time virtual sonography (RVS) combined with indocyanine green (ICG) fluorescent imaging technology in anatomical liver resection (ALR) for hepatocellular carcinoma. The clinical data of 41 patients who underwent ALR using RVS intraoperative navigation combined with ICG fluorescent imaging technology in the Department of Hepatobiliary Surgery of Peking University International Hospital from January 2020 to May 2022 were retrospectively analyzed. RVS was applied to guide the surgical plane through fusing real-time intraoperative ultrasound images with corresponding preoperative CT or MRI images. Operation methods, operation time, intraoperative blood loss, operative margin, hospital stay and postoperative complications were analyzed. The 1-year overall survival rate and tumor-free survival rate of patients were followed up by outpatient review or telephone calls. ALR surgery was performed on each of 41 patients. There were no deaths during perioperative period and postoperative complications occurred in 7 cases (17.1%). The postoperative pathological examinations demonstrated all cases of hepatocellular carcinoma and negative operative margins. The 41 patients were followed up for 12 to 20 months, with a median follow-up time of 14 months. The overall survival rate 1 year after surgery was 100.0% (41/41), 3 patients (7.3%) experienced tumor recurrence, and the tumor-free survival rate of 1 year after surgery was 92.7% (38/41). In conclusion, novel intraoperative navigation of RVS combined with ICG fluorescent imaging technology is safe and feasible in anatomical segmental hepatectomy of hepatocellular carcinoma.

Ex vivo photothermal treatment-induced immunogenic cell death for anticancer vaccine development

Photothermal therapy is an anti-cancer strategy that induce cell death by converting light energy into heat energy. During photothermal therapy, cancer cells were treated with photothermal agents, such as indocyanine green, and irradiated with a laser. Heat stress in cancer cells results in cellular death and inflammatory responses. In the present study, we demonstrated how ex vivo photothermal (PT)-treated cells underwent immunogenic cell death. PT treatment caused significant expression of heat shock protein (HSP) 27, HSP70, and HSP90 in murine tumor cells. To evaluate the immunogenicity of heat-stressed cells, lysate from PT-treated tumor cells or water-based heated cells was pulsed to syngeneic bone-marrow-derived dendritic cells (DCs) to generate a DC-based vaccine. Administration with PT-treated tumor lysates-pulsed DC vaccine resulted in significant inhibition of tumor growth in BALB/c and C57BL/6 syngeneic tumor-bearing mice. The immunogenicity of PT-treated cancer cells was reduced in the presence of HSP inhibitors, J2, VER-155008 or 17-AAG. Our study elucidates how PT techniques have distinct mechanisms from water-based heating and might be a potentially robust and efficient solution to developing an anti-cancer vaccine.

Near-infrared imaging of in vivo performance of orally administered solid forms to rats: Feasibility study with indocyanine green

This study demonstrates the applicability of near-infrared (NIR) imaging to evaluating in vivo oral formulation performance. As a NIR probe and model drug, indocyanine green (ICG) and acetaminophen (ACE) were selected, respectively. The fluorescence intensity of ICG greatly increased upon dissolution, with the dissolved ICG passing through the gastrointestinal tract over time. Both compounds (0.05 mg of ICG and 0.5 mg of ACE) were encapsulated in gelatin and hydroxypropyl methylcellulose (HPMC) capsules in the solid form. In vitro, the HPMC capsules showed a disintegration lag time, a feature that was not observed for the gelatin capsules. After oral administration of each capsule to rats, blood samples were collected, followed by fluorescent imaging of the abdominal region. At 0.25 h after HPMC capsule administration, the fluorescence area and intensity were significantly small and relatively weak compared to that of the gelatin capsule. These tendencies resulted from the difference in capsule disintegration times, leading to a change in gastric emptying, which corresponded well with the initial time profile of the plasma concentration of ACE. These results indicate that possibility of NIR imaging with ICG to evaluate in vivo performance of orally administered formulations.

Patient characteristics may affect the lymphatic staining ability of Indocyanine green and Patent blue during lymphaticovenous anastomosis

BACKGROUND

The use of dyes like Indocyanine green (ICG) and Patent blue facilitates the identification of lymphatic vessels during lymphaticovenous anastomosis (LVA) surgery. However, some patients experience "staining failure". In these cases, no stained lymphatic vessels can be detected, making supermicrosurgical LVA even more complex.

OBJECTIVE

This study aims to investigate patient-related factors that may interfere with lymphatic vessel staining during LVA.

METHODS

A retrospective study was conducted on 30 patient charts, focusing on patient characteristics and the staining quality of ICG and Patent blue dye. Statistical analyses were performed to identify correlations between variables.

RESULTS

Significant correlations were found between higher age and secondary lymphedema, longer duration of lymphedema in male patients until surgery and reoccurring cellulitis and Patent blue staining. Notably, recurrent infections to the lymphatic system resulted in inferior staining ability during LVA surgery.

CONCLUSIONS

Due to staining failure the detection of functional lymphatic vessels remains challenging in LVA surgery. A more extensive preoperative workup is recommended for patients with recurrent cellulitis to optimize surgical feasibility and procedure quality in LVA treatment for lymphedema.