The primary aim of this study was to determine the detailed anatomy of the lymphatics in the lower extremity using fresh human cadavers with indocyanine green (ICG) fluorescence lymphography. The secondary aim was to apply the anatomical results to establish a new protocol for lymphography based on feasible allocations for tracer injection sites.
One hundred lower extremities from 53 fresh human cadavers were used for this study. We injected ICG solution subcutaneously at 19 points around the foot along the border line between the dorsum and planta according to anatomical landmarks. Immediately after the ICG injections, gentle hand massage was applied at each injection site to facilitate ICG uptake into the lymphatic vessels. Fluorescent images of the lymphatics were obtained using a near-infrared ray camera system. Imaging data of the lymphatics was analyzed to find correlations between the injection sites and the identified lymphatic vessels.
The lymphatic system in the lower extremity was divided into four distinct lymphatic groups; anteromedial, anterolateral, posterolateral, and posteromedial. The lymphatic vessels in all except the posterolateral group connected to the inguinal nodes and those in the posterolateral group connected to the popliteal nodes. We successfully elucidated correlations between the injection sites in the foot and each lymphatic group.
The new classification of the four lymphatic groups in the lower extremity and identification of their origins in the foot enabled us to propose a new protocol for lymphography which includes four injection sites in specific circumflex locations.
1.Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama, Japan
2.Department of Plastic and Reconstructive Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama, Japan
3.Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
Financial Disclosure Statement: The authors have no financial interest to declare in relation to the content of this article.
Acknowledgments: I thank Philippa Sutton for editing the manuscript. This work was supported by the Japan Society for the Promotion of Science via Grants-in-Aid for Scientific Research (KAKENHI Award Number: 16K20358).
Corresponding author:: Akira Shinaoka, Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Science, 2-5-1 Shikata-cho, Kita-ku, Okayama-shi, 700-8558, Japan, Email: firstname.lastname@example.org