Systemic Elimination Rather than Redistribution: Segmental Body Water Analysis after Leg Lymphovenous Anastomosis

Abstract Lymphovenous anastomosis (LVA) is a microsurgical procedure that redirects stagnant lymph flow into the venous circulation, reducing fluid stasis in patients with secondary limb lymphedema. Although previous studies have reported that complex decongestive therapy redistributes fluid from the affected leg to other body segments, whether fluid reduction after LVA results from systemic elimination or intersegmental redistribution remains unclear. This study aimed to clarify the mechanism by analyzing the changes in segmental body water (SBW) volume using bioelectrical impedance analysis (BIA). We retrospectively analyzed the data of 40 Japanese women with unilateral stage II secondary leg lymphedema who underwent LVA from 2013 to 2021. Multifrequency segmental BIA was used to assess extracellular water, intracellular water, and SBW in the legs, trunk, and arms. Measurements were performed preoperatively and at least 12 months postoperatively. Changes in segmental and total body water (TBW) were statistically evaluated. Significant reductions were observed in SBW in the affected leg, and in the TBW (affected leg: 5.80–5.20 L, p < 0.001; TBW: 25.6–25.0 L, p = 0.002), with no significant changes in the unaffected leg, trunk, or arms. Extracellular and intracellular water in the affected leg decreased significantly (p = 0.001 and p < 0.001, respectively), whereas the percentage of extracellular water remained stable. LVA achieved sustained reductions in segmental and TBW volumes, localized to the affected leg, without compensatory increases in other body segments. These findings support the efficacy of leg LVA in achieving long-term fluid homeostasis through systemic elimination of excess lymphatic fluid rather than redistribution.