In ancient Yunzhou (Wang Yun County) there lived a family of hardworking people. The man plowed and the woman knitted, and the young couple worked very hard. One day the man returned from cutting firewood and carried back a pig feeding stone bowl from the mountains, the daughter-in-law liked it very much, and from then on there was a trough for feeding the pigs. The daughter-in-law fed the pigs every day, a pot of clear slop in only a few grains of rice, but poured into the antique stone bowl in a flash will become a pot of fragrant rice. The daughter-in-law told her husband, the two of them went to watch, the daughter-in-law’s earrings happened to fall into the stone bowl, and suddenly there was a bowl of bright shiny earrings. At this point they knew that this was the pot of treasures. This story sends people’s good wishes, what people need, just give a copy, the pot of treasures can be changed into countless copies. Modern dilator technology is the long sought after skin polygons in the medical community. Skin expander is a new technique to expand the soft tissues of the skin, which has been widely used in recent years in cosmetic plastic surgery. In the past, for skin scars, tissue defects, plastic repair, mainly relying on autologous tissue transplantation, so some people call plastic surgery is “tearing down the east wall to repair the west wall.” Sometimes for smaller skin scars, we can use the method of excision or stitching, and the surgical effect is ideal; but for larger scars, especially those on the face and head, we can only use the method of skin grafting. Although implantation has the effect of improving the function of scar, due to a series of problems such as skin color and skin margin scar after implantation, even if the implanted skin pieces survive well, it will not bring much improvement to facial beauty. However, due to the limited source of flaps and the need for 2 to 3 operations in stages, patients suffer more and it takes a longer time, still not out of the old box of “tearing down the east wall to repair the west wall”. The plastic principle of tissue expanders is to provide “extra” skin and soft tissue. The dilators currently used in clinical practice are mainly made of a silicone rubber material in the form of a capsule and are of two types. The commonly used one is the controlled dilator, which consists of three parts: dilating capsule, injection pot and catheter. 1, injection pot diameter of about 1 ~ 2cm, the base has a metal piece to prevent puncture too deep or puncture, the pot has a special one-way or two-way valve, liquid injection can be closed by itself, will not spill from the needle hole. 2.The connecting catheter is about 3mm in diameter and varies from 5 to 15cm in length. 3.The dilatation capsule is the main body of the dilator, which can be divided into round, oval, kidney, half-moon, rectangular, cylindrical, etc. According to the shape, its size can have many different specifications from 10ml to 800ml. The dilator is surgically implanted into the subcutaneous or submuscular layer, and sterile isotonic saline is injected into the injection jug periodically through the skin, and the latter flows into the dilating capsule along the catheter to expand the tissue. Another type of dilator is the self-expanding dilator, which is a sealed silicone rubber filled with a hypertonic saturated sodium chloride solution. Using the osmotic pressure difference between the inside and outside of the membrane, the tissue fluid penetrates into the dilating capsule through the capsule wall, an artificial semi-permeable membrane, and gradually expands the capsule volume to achieve the purpose of tissue expansion. The indications for skin soft tissue dilatation are very broad and can be used throughout the body in areas where soft tissue defects require additional skin repair. The advantage is that the “extra” skin tissue provided by this tissue expander is similar or identical to the skin around the defect area in terms of color, texture, thickness, sensation, hair distribution, and aesthetics, unlike implants, which produce new scarring of the donor area, and the procedure is simple and does not require high technical skills. The scalp is the best site for expander application, as long as the area of baldness does not exceed 2/3 of the whole scalp, there is hope to cover the whole scalp after expanding the remaining normal scalp; although the area of the scalp increases after expansion, the total number of hairs does not increase, only the spacing of hairs increases, which is actually the redistribution of hairs, and the hair is slightly thinner than normal after surgery, but it is usually not visible after the hair grows. All kinds of scars, whether located on the head and face or the trunk and extremities, can be repaired by soft tissue skin expansion as long as the scar area is not very large and there is normal skin available for expansion in the adjacent area. At present, all kinds of scars, especially post-burn scars, are the most commonly used conditions for skin soft tissue expansion; for the treatment of many post-burn deformities, skin soft tissue expansion is also the preferred repair method; for patients with insufficient skin supply area for large post-burn deformities, skin soft tissue expansion can be used for pre-expansion of the skin supply area, which can increase the amount of skin supply, and the skin supply area can be directly sutured. The expanded skin can also be used for full-thickness and medium-thickness implants, and its survival quality is better than that of ordinary skin pieces. Ear and nose reconstructions have very good results before applying dilation. Breast is one of the common sites for dilation, which can be used to prefabricate space for breast implants. Skin soft tissue expansion can also be combined with traditional flap grafting and skin tube transfer techniques to increase the donor flap area and reduce donor area deformities, thus improving the treatment results. Tissue expansion is usually performed in two phases. In the first stage of surgery, the size and shape of the dilator is selected preoperatively based on the site to be repaired, the morphology and extent of the lesion and the size and morphology of the normal skin available for expansion, and its quality is carefully checked and cleaned and disinfected after confirming that there is no breakage. The appropriate donor area is selected at the periphery of the defect area, and one or more dilators can be buried in one operation. The procedure can be performed under local or general anesthesia. The tissue expander is implanted through a small incision under the skin or muscle layer and the tissue is then sutured in layers. After the small incision has healed completely, sterile saline is periodically injected through the skin by puncture and via an injection jug. The volume of each injection should be 10-20% of the volume of the dilated capsule once a week. For example, for a 400 ml dilated bursa, the amount of saline injected should be 40-80 ml each time. The duration of the required dilation is usually 3 to 8 weeks. The dilated skin area should be twice the size of the defect area to repair the defect and close the donor wound. After the skin has been expanded to the desired level, the second stage of surgery can be performed, i.e., the tissue expander is removed through the original incision, the scar or diseased tissue in the defect area is excised, the skin that has been expanded to a certain level is advanced or rotated to the defect area, and the whole procedure is completed by plastic suturing. Self-expanding tissue expanders do not require regular saline injections after implantation under the skin, but the function of tissue expansion is weaker than that of the injection type. The injection jug can be built-in or external. When the jug is built-in, the skin needs to be punctured every time it is injected, and it is sometimes difficult to find the injection jug or inconvenient to deal with it when it leaks during the post-dilatation period; when the jug is external, the skin can be avoided to be punctured during the injection, but it is easy to cause infection and requires better care during the dilatation period. The dilatation capsule has good ductility and can be overdilated beyond its volume. After sufficient expansion, the expansion can be maintained for 1 to 2 weeks so that the soft tissues of the skin can be fully expanded to reduce skin retraction. Once the entire expansion process is completed, the second stage of the procedure can be performed to remove the expander and form an expanded flap to repair the defective area with the expanded tissue while preserving enough tissue to cover the donor area. If one expansion is not enough to repair the entire lesion area, the dilator can be reinserted under the flap in the second stage of surgery for “relay” expansion; or the dilator can be reinserted under the flap for second expansion six months after wound healing. After the second stage of surgical wound healing, measures should be taken to prevent scar growth and widening and to counteract flap contracture, such as elastic jackets, neck braces and stents. Early postoperative expansion flaps become hard and have a tendency to retract, and are generally able to soften and regain their natural elasticity 6 months after surgery. The disadvantages of skin soft tissue expansion are that the procedure needs to be performed in stages, the treatment time is long, the cost is high, and the elevation of the expanded area during expansion is an eyesore and there are some postoperative complications. Complications of skin soft tissue dilation include: hematoma, infection, exposure of the dilator, non-expansion of the dilator, pain, numbness, necrosis of the dilated skin, etc., all of which require timely and proper treatment, some of which require reoperation to remove the hematoma or replace the dilator, and some of which force the dilatation to be stopped for an earlier second stage surgery. The incidence of complications varies greatly from site to site, which is related to local anatomical features, generally the highest incidence in the face and neck, the lowest incidence in the scalp, the trunk and extremities in the middle. With the advancement of technology, experience, and improvement in the quality of dilators, the complication rate of skin soft tissue dilatation has gradually decreased. Despite its drawbacks, skin soft tissue dilatation is popular among patients and physicians because of its superior therapeutic effect and incomparable advantages over traditional methods. This technique is now quite mature and is widely used in many areas of plastic surgery, becoming one of the most basic and commonly used treatments in plastic surgery.