The purpose of this study is to evaluating whether autologous grafted fat transplantation or SVF transplantation is safe and/or effective to accelerating skin regeneration and soft tissue expansion.

Reconstruction of large scale skin defect is a challenge to clinical surgeons. Soft tissue expansion has won wide attention in recent years as it promotes skin regeneration with perfectly matched tissue. However, some patients with poor skin regenerative ability would suffer from skin flap over-thinned and even necrosis under the continuous stretching by silicone expander. This study is to evaluate the effects of autologous fat graft/SVF transplantation on accelerating skin regeneration and promoting tissue expansion process.

Patients aged between 18 to 60 years old who appear with deteriorated expanded skin will be enrolled and randomized into three groups, named as the experimental group and the control group. Patients from the FAT-GRAFT group will have a liposuction and subdermal fat graft transplantation. Patients from the SVF-TRANSPLANTATION group will have a liposuction and SVF will be separated and transplanted intradermally to expanded skin. Patients from the control group will have saline injection.

Inclusion Criteria:

• Inclusion Criteria:
• Age of 18 to 60 years;
• Expanding skin donor site at the face, neck, anterior chest wall, abdominal wall or back;
• Implanted silicone expander of 80 to 600 ml in size;
• History of deterioration in the expanded skin texture that did not improve after the inflation procedure was suspended for more than 2 weeks;
• Persistent high level of expander internal pressure;
• Need for further skin expansion;

Exclusion Criteria:

• Not fit for soft tissue expansion treatment;
• Evidence of infection, ischemia, ulcer or other pathological changes within the targeting area which defined as not suitable for expansion; or history of delayed healing, radiational therapy;
• Significant renal, cardiovascular, hepatic and psychiatric diseases;
• Significant medical diseases or infection (including but not limited to the carrier of hepatitis B virus or HIV)
• BMI >30;
• History of any hematological disease, including leukopenia , thrombocytopenia, or thrombocytosis;
• History of allogenic bone marrow transplantation;
• Long history of smoking;
• Evidence of malignant diseases or unwillingness to participate.