Vascularized axillary lymph node transfer: A novel model in the rat.

Vascularized lymph node transfer (VLNT) is a promising microvascular free flap technique for the surgical treatment of lymphedema. To date, few experimental animal models for VLNT have been described and the viability of lymph nodes after the transfer tested. We aimed to evaluate the feasibility of axillary VLNT in the rat. Lymph node containing flaps were harvested from the axillary region in 10 Lewis rats based on the axillary vessels. Flaps were transferred to the ipsilateral groin and end-to-side microanastomosis was performed to the femoral vessels using 10-0 sutures. Indocyanine green (ICG) angiography was used to confirm flap perfusion. On postoperative day 7, flaps were elevated to assess their structure and vessel patency. Hematoxylin and eosin staining was used to confirm the presence and survival of lymph nodes. All animals tolerated the procedure well. Immediate post-procedure ICG angiography confirmed flap perfusion. No signs of ischemia or necrosis were observed in donor extremities. At postoperative day 7, all flaps remained viable with patent vascular pedicles. Gross examination and histology confirmed the presence of 3.6 ± 0.5 lymph nodes in each flap without any signs of necrosis. This study showed that the transfer of axillary lymph nodes based on the axillary vessels is feasible. The flap can be used without the need for donor animals and it contains a consistent number of lymph nodes. This reliable VLNT can be further utilized in studies involving lymphedema, transplantation, and induction of immunologic tolerance.