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.