Stromal vascular fraction transplantation
BiologicalSubcutaneous fat was harvested from either the abdomen or the posterior inner thigh region and then digested with 600 U of collagenase (Shanghai Qiaoyuan Biological Pharmaceutical Co., Ltd, Shanghai, China) at 37°C and 150rpm for three hours. After enzymatic digestion, the lower aqueous phase liquid was aspirated to acquire the stromal vascular fraction (SVF). The SVF cell-pellet was washed and adjusted to 2×10^6 cells/mL. Lidocaine cream will be applied to the expanded skin to achieve surface anesthesia. The skin was marked with methylene blue and a total of 0.5ml (around 1×10^6 cells) were transplanted intradermally at the center of each 2cm×2cm squares. The expander was inflated two times a week using constant pressure inflation method, where the intracapsular pressure was monitored using a pressure meter and the inflation was halted when the pressure reached 100 mmHg.