Optimal Use Ratio of the Stromal Vascular Fraction (SVF): An Animal Experiment Based on Micro-CT Dynamic Detection After Large-Volume Fat Grafting.

Abstract

The addition of the stromal vascular fraction (SVF) can enhance the postoperative survival rate of fat. However, a universal SVF application method is currently unavailable. Therefore, a simple and convenient guideline for SVF addition is needed for its clinical application. The authors sought to evaluate whether SVF can improve fat survival after large-volume fat grafting and to find a simple and convenient standard for the clinical use of SVF. Patient fat samples were obtained after liposuction for SVF preparation and grafting. Four types of grafts were prepared with different SVF ratios: 0:1, 1:1, 2:1, and 4:1 SVF:fat. After intensive mixing, fat grafts (5 mL) were randomly injected into both sides of the backs of athymic rats (n = 15). At 24 hours and 1, 3, 6, and 9 months after the operation, microcomputed tomography scanning was performed to calculate the fat survival rate. Nine months after the operation, the survival rates of fat in the 4 groups were 8.89 ± 1.62% (0:1), 18.26 ± 3.85% (1:1), 8.83 ± 1.46% (2:1), and 7.96 ± 1.31% (4:1). The 1:1 group exhibited the greatest survival rate (P < 0.01), and the adipose tissue histological patterns and blood vessel quality were enhanced compared with those in the other groups. An appropriate SVF ratio can increase the fat survival rate after large-volume fat grafting, but no linear relationship exists between the SVF ratio and fat survival. The optimal SVF:fat ratio for grafting is 1:1.