Intraoperative identification and definition of “functional” lymphatic collecting vessels for supermicrosurgical lymphatico-venous anastomosis in treating lymphedema patients

Background: For current lymphatico-venous anastomosis (LVA), the identification of “functional” lymphatic collecting vessels (LCVs) is mainly based on indocyanine green (ICG) lymphography. However, some of the non-ICG enhanced LCVs utilized for LVA were found to have visual lymphatic flow. Objectives: Should non-ICG enhanced, but flow-positive LCVs be considered functional as well?. Methods: A retrospective study with 56 consecutive lymphedema patients (8 male/48 female) received LVA. LCVs were observed after ICG injection, before/after LVAs were performed. ICG enhancement and lymphatic flow in the LCVs were recorded and grouped as: Group A: all LCVs ICG(+) and flow(+); Group B: all LCVs ICG(+) and some were flow(+); Group C: some ICG(+) and some flow(+) LCVs; Group D: all LCVs ICG(−)but all flow(+); and Group E: all LCVs were both ICG(−) and flow(−). Results: A total of 366 LCVs were identified, averaging 8.2 LVAs, 6.5 LCVs, and 4.7 veins per patient. A total of 33 LVAs were performed with 27 LCVs with no ICG enhancement from 7 patients (Group D). These patients were satisfied with their lymphedema improvements. Conclusion: Lymphatic flow-positive but non-ICG enhanced LCVs, should also be considered as functional, thereby maximizing the number of functional LCVs for LVA.