Lower-Limb Lymphatic Drainage Pathways and Lymph Nodes: A CT Lymphangiography Cadaver Study

Abstract

I maging of the lymphatic vessels is an essential tool for diagnostic assessment of lymphedema. Lymphoscintigraphy is the current reference standard for lymphatic imaging (1-3). SPECT (4), indocyanine green (ICG) fluorescent lymphography (5-7), and MR lymphography (8) are emerging techniques. Lymphatic imaging of the lower limb requires intradermal or subcutaneous injection of tracer or contrast material in the foot to demonstrate the lymphatic vessels. No standard protocol exists, and single or multiple injections are applied at different sites.Each lymphatic vessel has an independent origin in the foot. The lymphatic vessel often branches and converges throughout its course, but it is uncommon to have interconnections with adjacent lymphatic vessels to produce a network. These characteristics allow us to categorize the lymphatic pathways in the lower limb into groups. Conventionally, the lymphatic pathways are divided into two groups: an anteromedial group connecting to the superficial inguinal lymph nodes and a posterolateral group connecting to the popliteal lymph nodes (9,10).Few anatomic studies have addressed the lymphatic vessels because of technical difficulties with their identification. Kinmonth and Eustace (11) developed lymphangiography and found that leg lymphedema is caused by deterioration of lymphatic vessels, lymph nodes, or both and that the pathologic process arose first in the lymph node. However, current lymphatic imaging protocols may miss information because of the lack of anatomic knowledge regarding the relationship between lymphatic vessels and their regional lymph nodes (12). Investigators of a previous study of ICG fluorescent lymphography in cadavers ( 13) classified lymphatic pathways into four distinct groups in the lower limb: anteromedial, anterolateral, posteromedial, and posterolateral. Origins of the lymphatic vessels in the foot may be defined in relationship to these four lymphatic groups, which could be selectively visualized with ICG lymphography.A limitation of previous studies was that the relationship between a lymphatic group and its regional lymph nodes could not be determined with ICG lymphography

Transpedal lymphatic embolization for lymphorrhea at the graft harvest site after coronary artery bypass grafting

“…However, this approach does not always allow visualization of complete lower leg lymphatics. Shinaoka et al [6] reported that injection into this web space demonstrates lymphatic vessels only in the anteromedial group. The anteromedial and posteromedial groups did overlap in the leg; however, the anterolateral and posterolateral groups were independent.…”

“…The intranodal approach has recently been introduced and remarkably reduced time and effort compared with the conventional pedal lymphangiography approach [3][4][5]. However, intranodal lymphangiography cannot be performed at the below-theknee level because the lowest lymph node is present in the popliteal area [6].…”

Value of one additional injection at the root of the limb in the lymphoscintigraphic evaluation and management of primary and secondary lower-limb lymphedemas

“…Consequently, we began to propose one additional injection at the root of the limb[s] to our patients. We were aware that one single injection could not reveal all LNs draining to the root of the edematous limb [ 13 ], but our intradermal injection in the lateral part of the thigh in front of the greater trochanter was chosen because we wished 1] to force with such intradermal injection [better than one subcutaneous one] [ 14 ] the quick demonstration a] of the presence of the most frequently expected lymphatic drainages toward unrecognized LNs at the level of the root of the limb[s] and/or in the abdomen and/or b] of possible posterior and/or lateral collateral lymphatic pathways at the level of the pelvis but also 2] to avoid or limit the possible “stardust” effect that might mask some LNs and/or draining LVs.…”

“…Consequently, we began to propose one additional injection at the root of the limb[s] to our patients. We were aware that one single injection could not reveal all LNs draining to the root of the edematous limb [13], but our intradermal injection in the lateral part of the thigh in…”

Oncologic Imaging of the Lymphatic System: Current Perspective with Multi-Modality Imaging and New Horizon

“…The superficial inguinal lymph nodes are further classified into five subgroups by the greater saphenous vein (GSV) and a horizontal line running through the saphenofemoral junction ( Figure 2 ). The five subgroups include superomedial, superolateral, inferomedial, inferolateral, and central groups [ 3 , 13 ]. The superomedial group drains the medial infraumbilical abdominal wall, medial gluteal region, external genitalia, lower anal canal, and the perianal region.…”