A novel endoscopic fluorescent band ligation method for tumor localization. Surg Endosc. 2016;30:4659-4663. [PMID: 26895900 DOI: 10.1007/s00464-016-4785-1]

Near-Infrared Fluorescence Image-Guided Surgery in Esophageal and Gastric Cancer Operations

Background

Near-infrared fluorescence image-guided surgery helps surgeons to see beyond the classical eye vision. Over the last few years, we have witnessed a revolution which has begun in the field of image-guided surgery.

Purpose, and Research design

Fluorescence technology using indocyanine green (ICG) has shown promising results in many organs, and in this review article, we wanted to discuss the 6 main domains where fluorescence image-guided surgery is currently used for esophageal and gastric cancer surgery.

Study sample and data collection

Visualization of lymphatic vessels, tumor localization, fluorescence angiography for anastomotic evaluation, thoracic duct visualization, tracheal blood flow analysis, and sentinel node biopsy are discussed.

Conclusions

It seems that this technology has already found its place in surgery. However, new possibilities and research avenues in this area will probably make it even more important in the near future.

Combined endoscopy/laparoscopy/percutaneous transhepatic biliary drainage, hybrid techniques in gastrointestinal and biliary diseases

In recent years, a wide range of gastrointestinal endoscopy techniques have been developed, such as endoscopic submucosal dissection (ESD) and endoscopic retrograde cholangiopancreatography (ERCP). Although ESD and ERCP have an important role in gastrointestinal and biliary diseases, each technique has its limitations. Hybrid techniques that combine endoscopic and surgical procedures have emerged that have the advantages of different procedures and negate their limitations at the same time. Laparoscopic endoscopic cooperative surgery and modified laparoscopic endoscopic cooperative surgery combine ESD and laparoscopic techniques to resect submucosal tumors with minimum resection area. Air leak test by intraoperative endoscopy can effectively identify a mechanically insufficient anastomosis and decrease the complication rate. The rendezvous technique that combines percutaneous transhepatic biliary drainage and endoscopy can be performed as a rescue approach for the treatment of biliary obstruction, stenosis and bile duct injuries. For patients with simultaneous presence of stones in the gallbladder and the common bile duct, the laparo-endoscopic rendezvous technique can perform ERCP and laparoscopic cholecystectomy at the same time and reduces the risk of pancreatic injury caused by ERCP. Biliobiliary and bilioenteric anastomosis using magnetic compression anastomosis is another choice for biliary obstruction. The most common used approach to deliver the magnets is by percutaneous-peroral tract. Laparoscopic-assisted ERCP is a safe and highly effective therapy for patients who develop biliary diseases after Roux-en-Y gastric bypass surgery.

Endoscopic Preoperative Tattooing and Marking in the Gastrointestinal Tract: A Systematic Review of Alternative Methods

Background: An accurate and reliable localization of endoluminal gastrointestinal (GI) lesions is crucial, particularly during minimally invasive surgery. As an extreme consequence, a misdetected GI lesion can lead to the resection of the wrong segment, especially in colorectal surgery. A preoperative endoscopic marking is recommended in case of GI lesions, which are expected to be difficult to detect from the serosal side. In clinical practice, three preoperative endoscopic marking methods are currently used: India ink, SPOT™, and endoclips with intraoperative fluoroscopy. All of them have substantial limitations. This has encouraged research on alternative solutions. Methods: In the current systematic review, animal and clinical studies about alternative preoperative endoscopic marking methods of GI lesions were analyzed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results: Thirty studies were found using PubMed/MEDLINE, EMBASE/Ovid, and the Cochrane Library for the qualitative analysis. Conclusion: Although several smart solutions have been proposed and tested successfully, all of them seem to have a substantial drawback related either to scarce stability on the marking site or potential spreading on the bowel wall or diffusion into the surgical planes.

Indocyanine green-loaded injectable alginate hydrogel as a marker for precision cancer surgery

Background

Accurate identification of tumor sites and boundaries is of paramount importance during minimally invasive surgery. Although laparoscopic resection is being increasingly and widely performed for early gastric and colorectal cancers, the detection of tumors located inside the stomach and intestine is difficult owing to the lack of tactile sensation. Here, we propose the application of an indocyanine green (ICG)-loaded alginate hydrogel system as a fluorescence surgical marker for precise laparoscopic operations.

Methods

A physical complex of ICG and human serum albumin (HSA) was mixed with sodium alginate to form an injectable hydrogel system. Calcium carbonate and D-gluconic acid (GA) were added to the gel to control its strength and gelation time, respectively. The optimal conditions for the preparation of injectable hydrogels were determined by analyzing the fluorescence spectra and sol-gel transition time of the prepared samples at various concentrations and compositions. Next, the aqueous solutions of ICG, ICG-HSA, and ICG-HSA-loaded alginate were subcutaneously injected into nude mice (three mice per group), and near-infrared (NIR) fluorescence images of the mice (λ_ex. =780 nm, λ_em. =845 nm) were obtained at different points in time for 8 days. Then, fluorescence intensities at the injection sites, target-to-background ratio, and areas of ICG fluorescence were analyzed. Finally, the potential utility of ICG-HSA-loaded alginate hydrogel as a surgical marker was evaluated in a porcine model. The ICG-HSA-loaded alginate solution was injected into three sites in the submucosal space of the porcine stomach via a catheter. A fluorescent laparoscopic system was installed on the abdomen of the pig 3 days post-injection, and the fluorescence signal generated from the fluorescence surgical marker located inside the stomach was evaluated using the fluorescence laparoscope system (λ_ex. =785 nm, λ_em. =805 nm).

Results

The optimal concentration of ICG-HSA complex was determined to be 30 µM, and maximum fluorescence intensity of the complex was obtained at a 1:1 mole ratio of HSA to ICG. The subcutaneous injection of ICG or ICG-HSA solution in mice resulted in the rapid spread of the fluorescence signal around the injection site in 3 h, and a weak fluorescence was detected at the injection site 24 h post-injection. In contrast, the fluorescence detection time was effectively prolonged up to 96 h post-injection in the case of ICG-HSA-loaded alginate gel, while diffusion of the injected ICG from the injection site was effectively prevented. In the laparoscopic operation, injection sites of the hydrogel in porcine stomach could be accurately detected in real time even after 3 days.

Conclusions

This alginate hydrogel system may be potentially useful as an effective surgical marker in terms of accuracy and persistence for laparoscopic operation.

NIR-II Fluorescence Endoscopy for Targeted Imaging of Colorectal Cancer

Endoscopy is a clinical gold standard to exam the interior of a hollow organ or body cavity. For the first of time, this study presents the design and construction of a fluorescent endoscopic system that harnesses the power of the second near-infrared window II (NIR-II) fluorescence imaging. An NIR-II fluorescent molecular probe, indocyanine green (ICG) conjugated bevacizumab (Bev-ICG) that targets vascular endothelial growth factor (VEGF), is successfully synthesized and evaluated along with the NIR-II endoscopy imaging system. Simultaneous NIR-II fluorescence and white-light (WL) imaging of VEGF is validated in an orthotopic rat colorectal cancer model. This NIR-II endoscopy system is a generalizable design, and it is compatible with the most of current clinic endoscopies. Similar hardware upgrades are expected to greatly promote the application of NIR-II fluorescent imaging in the clinic.

Enhanced cancer therapy with cold-controlled drug release and photothermal warming enabled by one nanoplatform

Stimuli-responsive nanoparticles hold great promise for drug delivery to improve the safety and efficacy of cancer therapy. One of the most investigated stimuli-responsive strategies is to induce drug release by heating with laser, ultrasound, or electromagnetic field. More recently, cryosurgery (also called cryotherapy and cryoablation), destruction of diseased tissues by first cooling/freezing and then warming back, has been used to treat various diseases including cancer in the clinic. Here we developed a cold-responsive nanoparticle for controlled drug release as a result of the irreversible disassembly of the nanoparticle when cooled to below ∼10 °C. Furthermore, this nanoparticle can be used to generate localized heating under near infrared (NIR) laser irradiation, which can facilitate the warming process after cooling/freezing during cryosurgery. Indeed, the combination of this cold-responsive nanoparticle with ice cooling and NIR laser irradiation can greatly augment cancer destruction both in vitro and in vivo with no evident systemic toxicity.