Yamamoto, Takumi

Abstract The vasa vasorum of the superficial collecting lymph vessel (VCL) has been reported to show morphological changes in lymphedematous limbs. This study aimed to develop a pathophysiological severity staging of the superficial collecting lymph vessels (SCLs) based on VCL morphology. A retrospective review was conducted using the medical charts of lower extremity lymphedema patients who underwent video‐capillaroscopy (VC) during lymphaticovenular anastomosis (LVA). Intraoperative SCLs were evaluated using VC at 175× and 620× magnifications. The VCL stage was determined based on VCL morphology observed under VC. D2‐40 (podoplanin) staining was assessed with a score of 0 for negative, 1 for mildly positive, and 2 for strongly positive. Red blood cell (RBC) movement was scored as 1 for movement and 0 for no movement. A total of 32 patients with 104 SCLs were evaluated. The distribution of VCL stages was as follows: Stage 0 in 4 SCLs (3.8%), Stage 1 in 16 SCLs (15.4%), Stage 2 in 18 SCLs (17.3%), Stage 3 in 36 SCLs (34.6%), Stage 4 in 20 SCLs (19.2%), and Stage 5 in 10 SCLs (9.6%). A significant difference was observed in the prevalence of lymphosclerosis grade according to the VCL stage ( p = 0.002). Among the VCL stages (Stage 1 vs. 2 vs. 3 vs. 4 vs. 5), a higher VCL stage was significantly associated with lower positivity to D2‐40 staining of the SCL ( p < 0.001), as well as with lower positivity to RBC movement in both the main VCL ( p < 0.001) and the branch VCL ( p < 0.001). These findings indicate that the progression of the VCL stage is associated with pathologic changes in the SCLs and physiological deterioration of the VCLs, highlighting the significance of the VCLs in the progression of lymphedema.