Vascularized Lymph Node Transfer from the Groin

Key Points

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The vascularized lymph node flap transfer from the groin was first introduced by Clodius in 1982 in two clinical cases.
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Animal studies described the vascularized lymph node flap as an effective technique for the treatment of lymphedema prior to most clinical studies.
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The vascularized groin lymph node can be independently transferred to the axilla, elbow, and wrist with promising results.
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The vascularized groin lymph node can be transferred to the axilla with the low abdominal flap, either the deep inferior epigastric perforator (DIEP) flap or the modified DIEP with nodes, without muscle.
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The vascularized groin lymph node flap has the advantages of a great number of lymph nodes, rich natural lymphaticovenous connection for drainage of lymph from the surrounding interstitial tissue, and a hidden donor site scar. However, it has the disadvantages of potential donor site lymphedema and poor cosmesis if transferred to distal recipient sites.

Introduction

In 1972, McGregor and Jackson designed a groin flap supplied by the superficial circumflex iliac artery (SCIA) and vein to reconstruct soft tissue defects of the hand. A decade later, Clodius utilized the same flap for its lymphatic benefits and subsequently proposed the use of this flap as a potential treatment option for lymphedema.

Several years later, Becker et al. demonstrated the use of this flap to treat patients with postmastectomy lymphedema. By placing the flap in the axilla, improvement was seen in most of the reported patients. Subsequently following this landmark study, Cheng et al. published their series placing the flap either in the wrist or elbow, further validating this treatment modality in patients with upper extremity lymphedema after mastectomy.

Despite these beneficial treatment effects, there continue to be concerns regarding donor site morbidity, relating to iatrogenic lymphedema of the lower extremity after flap harvest. However, cadaveric and imaging studies have delineated the anatomy and drainage patterns of groin lymph nodes, and novel reverse mapping techniques have allowed for reliable and safe inguinal lymph node harvest within a groin flap while minimizing the incidence of iatrogenic lymphedema.

In this chapter, we discuss the relevant anatomy of this flap, the techniques for successful flap harvest, major postoperative considerations/complications, and results following vascularized groin lymph node transfer (VGLNT).

Anatomy

Understanding the pertinent anatomy prior to attempting elevation of the groin flap is paramount to minimizing iatrogenic lower extremity lymphedema. Lymphatic fluid from the abdomen and leg drains toward the groin into distinct lymph node basins, termed superficial and deep lymph nodes. Based upon differences in drainage pattern, the groin has divisions responsible for drainage of lymphosomes, or lymphatic territories. Each lymphosome is responsible for draining a particular region of the abdomen or leg. Therefore, in order to avoid iatrogenic lower extremity lymphedema, only the lymph nodes draining the abdomen, and not those draining the leg, should be harvested within the flap ( Fig. 13.1 ).

Both the superficial and deep lymph nodes are located within the femoral triangle. The triangle is bordered medially by the adductor longus, laterally by the sartorius, and superiorly by the inguinal ligament. Proceeding from lateral to medial in the femoral triangle lie the femoral nerve, femoral artery, and femoral vein. Medial to the vein are the deep lymph nodes that receive drainage from the lower extremity. Lymphatic channels originating from the leg converge and travel parallel with the great saphenous vein, eventually draining into these deep lymph nodes in the distal part of the femoral triangle.

Whereas the deeper lymphatic structures are responsible for drainage of the leg, the superficial lymphatic structures drain the lower abdomen. These superficial lymph nodes are located superior in the femoral triangle, near the lower edge of the inguinal ligament, and lie superficial to the deep fascia. Based on cadaveric and radiographic studies, there are approximately six to eight superficial lymph nodes per groin, with half being supplied by branches of the SCIA. The majority of these lymph nodes are clustered between the superficial circumflex iliac vein (SCIV) and superficial inferior epigastric vein (SIEV).

The traditional groin flap as described by McGregor and Jackson involved designing a flap based off the main axis of the SCIA vessels. The flap included all soft tissue including the superficial lymph nodes and potentially deeper nodes and portions of the deep fascia. Although effective, limitations to this flap are its bulkiness, short pedicle length, and increased risk of iatrogenic lymphedema. To resolve this, a variation of the groin flap termed the superficial circumflex iliac artery perforator (SCIP) flap was developed for soft tissue reconstruction. Understanding that a single dominant perforator from the SCIA can supply a large skin territory has allowed for the use of this flap. In addition, slight deepening of this flap to include subscarpal tissue can result in the inclusion of the superficial inguinal lymph nodes as demonstrated ( Figs. 13.2–13.4 ).

Role of Reverse Mapping

An adjunct to facilitate flap dissection and minimize iatrogenic lymphedema in the lower extremity is a technique termed reverse mapping. This technique involves the injection of technetium in the distal lower extremity utilizing a gamma probe to identify lymph nodes that drain the extremity versus the lower abdomen. In contrast, indocyanine green (ICG) is injected into the lower abdomen in order to distinguish the desired lymph nodes from deeper nodes that drain the lower extremity. This selective node sampling technique allows for safe harvest of lymph nodes within this region, as well as in the axillary region.

Preoperative Navigation

With assistance from radiologic imaging, narrow gated computed tomography (CT) scans and CT angiography may help guide the surgical planning for vascularized lymph node transfer ( Figs. 13.5 and 13.6 ). This may reduce time to harvest and may decrease the risk of complications of the donor site.