What is a thinning flap? A thinning flap is a one-stage (direct intraoperative thinning) or two-stage (one or two stages at 3 months postoperatively) trimming of the subcutaneous fat tissue from the flap that covers the trauma, in order to make the flap more cosmetically and functionally pleasing to the eye. What are the benefits of one-stage flap thinning? The benefits of one-stage flap thinning are 3-fold: 1. One-stage thinning can reduce the number of surgeries, reduce the pain of patients in separate surgeries, and save the cost of hospitalization; 2. One-stage thinning can preserve the vascular nerves, so that the blood flow and sensation of the flap can be preserved to the maximum extent, and reduce the flap’s fear of cold and the formation of ulcers; 3. Because the thickness of the flap can be reduced to 1/1/1/3 of the original thickness, it can narrow down the flap’s size, so that the donor area can have less skin grafting or no skin grafting. How difficult is one-stage flap thinning? One-stage thinning prolongs the operation time and easily destroys the blood circulation of the flap, causing partial or total necrosis of the flap. Based on a large number of experiments and clinical practice, we can perform one-stage thinning under the microscope to protect the blood vessels from being damaged, and try to trim off the subcutaneous fat to minimize the pain of the second-stage surgery.