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

[BACKGROUND] 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.

[OBJECTIVES] 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.

[METHODS] 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.

[RESULTS] 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.

[CONCLUSIONS] 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.