The Venous Lymph Node Flap: Concepts, Experimental Evidence, and Potential Clinical Implications

Abstract

Background Traditionally, lymph node flaps (LNF) have been designed as arteriovenous flaps, with little attention given to the functional anatomy of lymphatic system included in the flap. Based on the anatomical and physiological features of lymphatic system, we believe that a new concept of LNF, the venous LNF, should be investigated. In this article, we report the concepts and findings of venous LNF, and help gauge its potential clinical application in the treatment of lymphedema. Methods Eight healthy Wistar rats underwent cervical LNF harvesting along the right external jugular vein, right inguinal node clearance, and venous LNF transfer in a flow-through fashion along the femoral vein. At 45 postoperative days, the restoration of lymphatic continuity with surrounding tissue was verified with intradermal injection of 0.1% of methylene blue. The flaps were then excised and sent for histologic evaluation. Results All rats survived uneventfully in the postoperative period and no postoperative complications were experienced. The venous anastomosis was proven to be patent clinically. In all rats we found reestablishment of lymphatic continuity with surrounding tissues. Histologically, the nodes showed the following main histoarchitectural changes: drastic reduction of the stromal compartment and preservation of the lymphatic/sinus and vascular compartments. Conclusions The novel venous LNF flap is able to restore lymphatic continuity with surrounding tissue. As healing occurs, the lymph nodes undergo major histoarchitectural changes. The venous LNF has unique theoretical advantages over arteriovenous LNFs. Further investigations would be beneficial to understand its potential in the surgical treatment of lymphedema.

Evaluation of the External Jugular Vein Overlying the Sternocleidomastoid Muscle as Venous Lymph-Node Flap

“…However, the exact physiology of venous flaps still remains unclear. Before the innovative work of Visconti and associates [ 14 ], research and clinical work in the surgical treatment of lymphedema focused on VLNT with an arterial and venous donor vessel [ 18 , 19 ]. Visconti et al established the hypothesis that the lymphatic functional unit consists of lymph nodes, lymphatic vessels and surrounding veins [ 14 , 15 ].…”

“…Before the innovative work of Visconti and associates [ 14 ], research and clinical work in the surgical treatment of lymphedema focused on VLNT with an arterial and venous donor vessel [ 18 , 19 ]. Visconti et al established the hypothesis that the lymphatic functional unit consists of lymph nodes, lymphatic vessels and surrounding veins [ 14 , 15 ]. They were able to create a rat model and show the potential benefits in the treatment of lymphedema [ 14 ].…”

“…Visconti et al established the hypothesis that the lymphatic functional unit consists of lymph nodes, lymphatic vessels and surrounding veins [ 14 , 15 ]. They were able to create a rat model and show the potential benefits in the treatment of lymphedema [ 14 ]. The lymph-node flap based on the rat’s EJV was able to drastically reduce edema and restore lymphatic drainage.…”

“…However, lymph nodes are mainly linked to the venous system and it is often not clear whether there is an arterial supply at all. Thus, Visconti and colleagues have recently proposed a new concept: the venous lymph-node flap, a vein and the attached lymph nodes are transplanted [ 14 ]. They created an experimental model in rats that showed the reestablishment of lymphatic flow after transplantation of a vein with surrounding tissue.…”

Validation and efficacy of ‘pure’ venous lymph node flap in a rat lymphoedema model

“…Recently, it was suggested the concept of venous lymph node flap (vLNF), referring to a LNF that solely rely on the venous system, differing from the traditional vascularized LNFs. 12 In a previous study conducted by the authors, it was introduced as a new classification of vLNFs the arterialized and 'pure' venous flaps that are based on the nourishing vessel type. 13 However, whether the vLNF drainage function is maintainable or sufficient for lymphoedema treatment is yet to be investigated.…”