The purpose of this study is to optimize the expansion pressure by compare different capsule pressures' effect, the blood supply of expanded skin is assessed by the Indocyanine Green-SPY Angiography.

This is a randomized controlled trial that designed to optimize the tissue expander expanding method. All the patients were randomly divided into five groups, patients in different groups received an expansion weekly with different capsule pressure of 60mmHg, 70mmHg, 80mmHg, 90mmHg and 100mmHg respectively. Each patient received an expanding once a week, and a hemodynamic assessment of SPY-ICG angiography every two weeks. The total follow-up for each patient is 8 weeks.

Inclusion Criteria:

• Age of 18 to 50 years;
• Expanding skin donor site at the face, neck, anterior chest wall or back;
• Implanted silicone expander of 100 to 600 ml in size; The quantitiy of normal saline in the tissue expander is more than the original volume, and less than double original volume.
• Need for further skin expansion; with previous regular expanding in hospital;

Exclusion Criteria:

• Iodine allergy; Indocyanine green allergy;
• 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.