Subcutaneous 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.

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 0.9% normal saline 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.

Subcutaneous 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.

Using Doppler ultrasound to measure the full-thickness of skin dermis of the expanded skin. The measurements were conducted at the center of the expanded skin and other four points (above, below, left, right) around the center. The average value is taken to represent the dermal thickness of the patient's expanded skin.

Using the HSCAN771 handheld laser 3D scanner and the VIVID910 3D laser scanning system to measure the surface area of the expanded skin.

Using the VISIA skin analyzer to visualize the distribution of dermal marks, which is an indication of dermal rupture. Briefly, photographs of the patient's expanded skin were taken from three standard angles: front, left side, and right side. Use the VISIA instrument to generate texture imaging of the expanded skin, selecting the expanded skin and surrounding normal skin as the region of interest. Employ the instrument's built-in red area analysis function to analyze the distribution of dermal marks in the expanded skin.

Using the elasticity probe of CK Skin analyzer to measure the elasticity of the expanded skin. Represent skin softness through the skin viscoelasticity parameter R2 (R2 = Ua/Uf, where Ua is the total elastic and plastic recovery, and Uf is the total elastic and plastic deformation).