A phase III, multicenter, single-arm study to assess the utility of indocyanine green fluorescent lymphography in the treatment of secondary lymphedema

Diagnosis and Treatments of Limb Lymphedema: Review

Lymphedema is caused by dysfunction of the lymphatic system. It is divided into primary edema with no apparent cause and secondary edema with an exogenous cause. The main symptoms are edema and heaviness, skin changes such as skin hardening, lymphocysts, lymphorrhoea, papillomas, and recurrent cellulitis. They are often irreversible and progressive, thus greatly reducing quality of life of the patients. Diagnosis is made by image examinations that can evaluate lymphatic flow and functions such as lymphoscintigraphy and indocyanine green fluorescence lymphangiography. Linear pattern and dermal backflow are the main findings. Conservative treatment consists of four components: compression therapy with elastic garments, exercise therapy, manual lymphatic drainage, and skin care, which is called complex physical therapy (CPT). Although CPT has become the gold standard of treatment, with evidence of efficacy reported in terms of volume reduction, maintenance, and prevention of cellulitis, it is a symptomatic treatment and does not improve impaired lymphatic flow. On the other hand, surgical treatment, such as lymphaticovenous anastomosis and vascularized lymph node transplantation, can create new lymphatic flow and improve lymphatic dysfunctions. Although these techniques are expected to be effective in volume reduction, cellulitis prevention, and improving quality of life, there is a need for more studies with a higher level of evidence in the future. In Japan, lymphedema is treated with a combination of conservative and surgical therapies, but lymphedema is intractable and few cases are completely cured. Therefore, how to improve the outcome of treatment is an important issue to be addressed in the future. (This is a translation of Jpn J Vasc Surg 2023; 32: 141-146.).

Research progress of indocyanine green fluorescence technology in gynecological applications

Indocyanine green is a near-infrared fluorescent dye which is widely used in various fields of surgery and gynecology. It is currently mainly used to detect various malignant tumors, sentinel lymph nodes, endometriosis lesions, ureter or intestinal occlusion, vaginal perfusion, uterine arterial blood perfusion, pelvic nerve, uterine niche, lymphatic edema, metastatic lesion shadow, and so on, providing new methods for decision-making during surgery. This article elaborates the application progress of indocyanine green fluorescence technology in gynecology.

A new lymphography protocol and interpretation principles based on functional lymphatic anatomy in lower limb lymphedema

Indirect lymphatic system imaging is essential for diagnosing lymphatic diseases. The basic methodology involves intradermal or subcutaneous injection of a contrast agent into the surrounding lymphatic capillary, and the flow of the contrast agent is identified using a detector. Many contrast agents that use near-infrared dye, including indocyanine green (ICG) fluorescent lymphography, are available. ICG is rapidly spreading as a convenient and safe lymphedema diagnostic method, because it does not involve radiation exposure, and the imaging equipment is more compact than other devices. The lymphatic system is a semi-open circulatory system with numerous lymphatic capillaries acting as blind ends. Anatomical information on the injection site and observation of specific lymphatic vessels and nodes is important. However, this anatomical information is lacking. Recent reports suggest that ICG fluorescent lymphography can be applied to cadavers in the same manner as living bodies. Furthermore, these reports have demonstrated the functional aspects of the capillary lymph vessel networks as well as their relationship with lymphatic vessels and lymph nodes. This review article describes the historical progression from the old to the new functional lymphatic anatomy and introduces a new functional lymphography technique for the lower limbs.

Fluorescence-guided surgery: comprehensive review

BACKGROUND

Despite significant improvements in preoperative workup and surgical planning, surgeons often rely on their eyes and hands during surgery. Although this can be sufficient in some patients, intraoperative guidance is highly desirable. Near-infrared fluorescence has been advocated as a potential technique to guide surgeons during surgery.

METHODS

A literature search was conducted to identify relevant articles for fluorescence-guided surgery. The literature search was performed using Medical Subject Headings on PubMed for articles in English until November 2022 and a narrative review undertaken.

RESULTS

The use of invisible light, enabling real-time imaging, superior penetration depth, and the possibility to use targeted imaging agents, makes this optical imaging technique increasingly popular. Four main indications are described in this review: tissue perfusion, lymph node assessment, anatomy of vital structures, and tumour tissue imaging. Furthermore, this review provides an overview of future opportunities in the field of fluorescence-guided surgery.

CONCLUSION

Fluorescence-guided surgery has proven to be a widely innovative technique applicable in many fields of surgery. The potential indications for its use are diverse and can be combined. The big challenge for the future will be in bringing experimental fluorophores and conjugates through trials and into clinical practice, as well as validation of computer visualization with large data sets. This will require collaborative surgical groups focusing on utility, efficacy, and outcomes for these techniques.

Imaging of the Lymphatic Vessels for Surgical Planning: A Systematic Review

BACKGROUND

Secondary lymphedema is a common complication after surgical or radiotherapeutic cancer treatment. (Micro) surgical intervention such as lymphovenous bypass and vascularized lymph node transfer is a possible solution in patients who are refractory to conventional treatment. Adequate imaging is needed to identify functional lymphatic vessels and nearby veins for surgical planning.

METHODS

A systematic literature search of the Embase, MEDLINE ALL via Ovid, Web of Science Core Collection and Cochrane CENTRAL Register of Trials databases was conducted in February 2022. Studies reporting on lymphatic vessel detection in healthy subjects or secondary lymphedema of the limbs or head and neck were analyzed.

RESULTS

Overall, 129 lymphatic vessel imaging studies were included, and six imaging modalities were identified. The aim of the studies was diagnosis, severity staging, and/or surgical planning.

CONCLUSION

Due to its utility in surgical planning, near-infrared fluorescence lymphangiography (NIRF-L) has gained prominence in recent years relative to lymphoscintigraphy, the current gold standard for diagnosis and severity staging. Magnetic resonance lymphography (MRL) gives three-dimensional detailed information on the location of both lymphatic vessels and veins and the extent of fat hypertrophy; however, MRL is less practical for routine presurgical implementation due to its limited availability and high cost. High frequency ultrasound imaging can provide high resolution imaging of lymphatic vessels but is highly operator-dependent and accurate identification of lymphatic vessels is difficult. Finally, photoacoustic imaging (PAI) is a novel technique for visualization of functional lymphatic vessels and veins. More evidence is needed to evaluate the utility of PAI in surgical planning.

Clinical and Histological Effects of Partial Blood Flow Impairment in Vascularized Lymph Node Transfer

Regarding vascularized lymph node transfer (VLNT) for lymphedema, partial blood flow impairment in transferred lymph node (LN) flaps may adversely affect the therapeutic results. We investigated the clinical and histological effects of partial blood flow impairment in LN flaps. In upper extremity lymphedema cases, based on ultrasonographic examination at 2 weeks after VLNT, we compared the treatment results depending on whether the postoperative blood flow in transferred LNs was good (Group G) or poor (Group P). Novel partial ischemia and congestion of LN flap mouse models were developed to determine their histological features. In 42 cases, significant differences were observed between Group G (n = 37) and Group P (n = 5) based on the amount of volume reduction (136.7 ± 91.7 mL and 55.4 ± 60.4 mL, respectively; p = 0.04) and lymph flow recanalization rate in indocyanine green fluorescent lymphography (67.6% and 0%, respectively; p = 0.0007). In mouse models, thrombi formation in the marginal sinus and numerous Myl9/12-positive immunocompetent cells in follicles were observed in congested LNs. Blood flow maintenance in the transferred LNs is an essential factor influencing the therapeutic effect of VLNT. Postoperatively, surgeons should closely monitor blood flow in the transferred LNs, particularly in cases of congestion.