The purpose of this study is to evaluating whether autologous bone marrow mononuclear cells 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. Although, on some occasions, decelerating the expander inflation process could reduce the incidence of necrosis, this prolonged therapy circle is to be accompanied with increased complications, including infection and expander rupture, as well as the increased economic expenses by the longer hospitalization. This study is to observe the effects of autologous bone marrow mononuclear cell 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 two groups, named as the experimental group and the control group. Patients from the experimental group will have a bone marrow aspiration and intradermal mononuclear cells transplantation. On the other side, Patients from the control group will have saline injection.

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.