Intratissue Lymphovenous Communications in the Mechanism of Action of Vascularized Lymph Node Transfer

Background and Objectives: Vascularized lymph node transfer (VLNT) as a surgical treatment for cancer-related lymphedema has shown beneficial effects. The mechanism of action of this procedure involves lymphangiogenesis and lymphovenous communications (LVC) within the lymph nodes. We propose intratissue LVC as an additional element responsible for drainage of lymph to blood in the flap and examine this hypothesis in the current study. Methods: This prospective study determined the passage of lymph to the venous system via intratissue LVC in 26 free flaps used for breast reconstruction. We evaluated whether fluorescence was positive in the pedicle vein after increasing time intervals following intradermal injection of indocyanine green (ICG) dye into the flaps using near infra-red fluorescence lymphography. Results: We studied 26 free flaps, 22 deep inferior epigastric perforator (DIEP) flaps (84.6%), and 4 superior gluteal artery perforator (SGAP) flaps (15.4%). Fluorescence in the pedicle vein was positive in 22 of the 26 flaps (P = 0.000). The median time for fluorescence evaluation in the pedicle vein was 120 min. Conclusions: Fluorescence in the pedicle vein after ICG intradermal injection indicates functional intratissue LVC in free flaps. (C) 2016 Wiley Periodicals, Inc.