The success of autologous fat grafting for filler depends on a number of factors, including the acquisition of autologous fat, the selection of the donor area, the purification of the granulated fat, the method of grafting, the condition of the recipient area, and the post-surgical management. Some doctors compare fat grafting for filler to sowing seeds in a field. To achieve the best harvest, each of the above elements needs to be optimized and kept in a balanced consistency, and the acquisition of the seed, granulated fat tissue, is the first step that needs to be addressed. There are many methods of liposuction, such as vacuum-negative machines, ultrasonic liposuction machines, electronic liposuction machines, resonance liposuction machines, and hydrodynamically-assisted liposuction, but with the exception of the last one, the fat tissue obtained by the other methods is not suitable for transplantation. Syringe liposuction began in 1974 and is still the most commonly used clinical method because of its simplicity, low cost, and high safety. After syringe liposuction, there is no local dead space, and there is liquid cushioning, small mechanical friction of fat suction, no fat vaporization, less damage to the suctioned fat, so that the suctioned fat maintains good vitality, which is conducive to the autologous free grafting of fat particles; and the use of syringes to suction the fat is accomplished in the closed aseptic system, which is better than the use of the fat collection system of the other fat suction methods (the general fat collection system), which has long paths and more complex structures. Moreover, the use of syringe liposuction is done in a closed and sterile system than the fat collection system of other liposuction methods (the general fat collection system has a long path and complicated structure), and the chance of fat contamination is reduced. I. Swelling anesthesia Swelling anesthesia is mostly used in syringe liposuction method, which is characterized by the following features: greater inter-tissue pressure after hyperinfusion, vascular compression, and reduction of local perfusion; infiltration of a large amount of saline solution, which makes the adipose tissues mechanically expanded and enlarges the tissue interstitial space; lidocaine is an amide-type local anesthetic with lipophilicity, and the adipose tissues can prevent its diffusion and absorption; the pressure of swelling makes it easy for the adrenaline in the solution to enter the cells, thus enabling further vasoconstriction; in addition, a significant portion of the swelling solution is expelled with aspiration. For the above reasons, the absorption of lidocaine is slow, and it is not easy to reach the toxic concentration in the plasma, and it also makes it easier to pass the pipette when suctioning, with less damage to blood vessels, less bleeding, and it is easier to completely suction out the fat, thus increasing the degree of safety. Second, the choice of donor area Commonly used fat donor areas are upper and lower abdomen, iliac waist, thighs, buttocks, upper arms and other parts of the body, it has not yet been clarified whether the source of fat from different parts of the body has an impact on the survival rate of fat tissue after transplantation. Some scholars have found that adipocytes in the buttocks and lateral thighs are the largest, and that adipose tissue in these areas has high protease activity, and thus is thought to have the strongest ability to generate fat. Some scholars believe that the fat tissue in the buttocks and outer thighs can be better used as the donor area for fat transplantation, where the fat is relatively stable, not easy to change with body weight or dieting, the fat cell volume is small, dense, and the number of intact fat cells is significantly more than that of the abdomen, so the injection and transplantation effect is better than that of the abdominal fat. Meanwhile, some experimental studies have proved that most of the stem cells of fat source gather around blood vessels, and the subcutaneous fat of human abdomen and thigh has the most fat stem cells. Therefore, the most commonly used donor areas are thighs and lower abdomen. Of course, there are scholars with different attitudes, foreign scholars and other control analysis of the use of liposuction collected from the abdomen, lateral abdomen, thighs, knee joint medial fat, the use of in vitro colorimetric assay to detect the number of cell proliferation to analyze the viability of cells, the results of the analysis of the fat extracted from the four donor areas in the fat viability was not statistically significant. vonHeimburg et al. compared the use of liposuction and direct shredding method of fat stem cells, and the use of fat stem cells in the lower abdomen and thighs. aspiration and direct shredding methods to obtain precursor adipocytes originating from the abdomen, chest, and buttocks, and found that more than 94% of the precursor cells were viable in all sites, suggesting that the number of viable cells obtained from different sites was similar. ullmann et al. injected granular fat obtained from the human abdomen, breast, and thigh into 3 different sites in the body of nude mice, and after 16 weeks, they observed that the mass of the fat after transplantation was found to be similar, volume, and histologic characteristics were not significantly different. Different parts of the body have different fat cells, different metabolisms and different blood supplies, so the optimal choice of donor area is not yet clear. Many people choose the lateral thighs as the ideal fat source because there are few fibers in the fat and it is a relatively avascular area; in addition, the fat cells in this area are dense and the number of intact fat cells that can be obtained is high. Third, the choice of suction needle and syringe syringe liposuction to obtain particulate adipose tissue in the process of selecting blunt, sharp, thick and thin, suction hole size and negative pressure appropriate fat suction needle is very important, the appropriate suction needle can make the maximum amount of suction, tissue damage is the least, the minimum running resistance and to obtain the size and vitality of the particles of fat satisfactory. Comprehensive literature, the current more unified view that: liposuction needle should be selected blunt or bullet-shaped, should be with the main suction holes and side holes, the diameter of the appropriate between 2 ~ 4mm, which can increase the contact area with the adipose tissue, running resistance is smaller, so that the labor intensity is reduced and to reduce the donor area damage. Although fat particles obtained with large diameter liposuction needles may have higher activity, they are not suitable for fat grafting in fine areas due to the large size of the particles, whereas liposuction needles with a diameter of 2 mm can obtain tiny fat particles or ultramicro fat particles. The syringe is mostly used 10mL and 20mL two specifications. (1) Preoperative preparation: routine determination of bleeding and clotting time, women in the non-menstrual period, excluding other contraindications to surgery. (2) Routine sterilization sheet, drawing the liposuction range, incision line length 3 ~ 5mm, try to choose hidden parts. Abdominal incision is chosen in both sides of the iliac bone next to or around the umbilicus; the back waist is chosen in both sides of the waist-hip junction; buttocks and thighs are chosen in the hip-femoral and inguinal fold outer 1/3. (3) Using the swelling anesthesia method, inject the fat donor area until the skin is slightly white and hard. (4) Use the syringe to connect the appropriate diameter of liposuction needle through the incision into the subcutaneous adipose tissue, forcefully pull the liposuction syringe core, and then fixed to radial fan for suction, when the syringe is more extracted, the negative pressure is insufficient to empty the syringe in time, and then again for suction. (5) When suctioning, hold the syringe with one hand, lift the liposuction area with one hand or put it flat on the skin surface to sense and grasp the direction and level of suction, and pay attention to changing the direction and location of the needle when there is bright red blood suction. When suctioning to the superficial layer of fat, in order not to damage the subdermal vascular network, generally retain at least 1 ~ 1.5cm of subcutaneous fat. Avoid uneven levels of suction, resulting in unevenness. Tip: The choice of fat aspiration method will affect the activity of fat particles and also the yield of ADSCs. The method of obtaining fat particles by syringe, although there are controversies in the selection of the donor area, the size of the diameter of the liposuction needle, and the negative pressure of liposuction, this method has a small negative pressure and a fine diameter of the liposuction needle, which is less damaging to the fat cells and is conducive to the survival and differentiation of the fat cells, and it has the advantages of having no obvious scar remaining in both the donor and recipient areas, easy operation, and high repeatability, which makes it one of the currently recognized means of obtaining fat particles. At the same time, we also recognize that this method is time-consuming and laborious, and it takes many times of reciprocal pumping to pump fat to a site, and repeated puncture and suctioning will cause some damage to the vascular nerves, and also cause more damage to the incision of the needle hole, and sometimes delayed healing of the incision will occur. For medium and small amount of fat grafting, the conventional negative pressure suction method is preferred, and can also be used for large amount of fat grafting.