The first laser machine was invented by Maiman in the United States in 1960, and since then lasers have been rapidly used in various fields, including medicine. Based on the high energy, single wavelength and precision of laser, laser is mostly used in medicine instead of conventional scalpel for some treatment of cutting and tissue removal, and the main ones that can provide high power laser output for such treatment are CO2 laser and Nd:YAG (neodymium-doped yttrium aluminum garnet) laser, while CO2 laser can only be conducted through the joint arm of the combined lens at present, and its use is only limited to the treatment of surface lesions or cutting, and cannot be inserted into tissues for treatment. It cannot be inserted into the tissue for treatment. The Nd:YAG laser, with a wavelength of 1064 nm, can be transmitted through a quartz fiber so that it can enter the tissue for operation. Its output power can reach tens or even hundreds of watts, and the pulse interval can be controlled to milliseconds or even nanoseconds, which is ideal for a variety of surgical operations for different purposes, and its fiber optic transmission system can also give the surgeon a sense of physical operation for easy control. Using the thermal effect of the YAG laser on the tissue, the intra-tissue inserted YAG laser can be used to melt subcutaneous fatty tissue, which can be applied in plastic and cosmetic surgery for fat melting treatment of the head and face. Laser fat melting equipment configuration, Nd:YAG laser, wavelength 1064nm, laser transmission through 300μm diameter optical fiber, He-Ne laser (wavelength 632.8nm) as a guide light and indicator light, used to show the laser head action direction and position. A protective metal catheter of 1mm in diameter and 15cm in length is attached to the front of the fiber, which is inserted into the tissue to reach the desired treatment site to melt the fatty tissue. The general treatment steps are as follows: 1. The optical fiber is inserted into a handle with a cannula (different lengths are available depending on the area to be treated). The distal end of the optical fiber should extend beyond the cannula by 2 to 3 mm. 2.Mark the treatment area on the skin surface. 3.Under local anesthesia, an incision of 2 to 3 mm in length is made with a scalpel for insertion of the treatment cannula. 4, Through the incision site, a certain amount of swelling anesthetic solution is injected into the subcutaneous tissue. 5. The cannula with fiber optics is inserted and the laser is activated. The general parameter selection is 40 Hz/150 mJ. The laser head emits laser light while moving within the tissue, and if the treatment head stops moving, the laser emission should be stopped at the same time to avoid burning the tissue. The operator can adjust the moving speed of the treatment head by observing the red laser at the treatment head, which is generally between 5-10m/s. 6.Remove the cannula and use negative pressure liposuction to extract the melted fat. 7.The treatment area is wrapped with pressure outside the conventional department. The action of laser on biological tissues has diversity, strong laser is mainly the use of laser photothermal effect, light blasting effect and other effects on the tissue, so that the tissue generated high heat, coagulation or vaporization and achieve the corresponding treatment purpose. nd:YAG laser wavelength of 1064nm, is an infrared spectrum, invisible to the naked eye. It has a strong penetrating ability in soft tissues, up to a distance of 3-5mm, and can be conducted through optical fibers, making it possible to play a role in fat melting. Facial contour is determined by a variety of factors. The human cheek is mainly composed of skin, cheek fat pad, muscles and bones, the skull is the basic scaffold, and the amount and distribution of soft tissues determines the shape of the face with a distinct personality that varies widely. Therefore, the unsatisfactory face shape caused by excessive facial fat can be treated by liposuction. The distribution of facial fat has distinctive characteristics, and according to the amount of fat distribution, it can be divided into fatty areas, less fatty areas and fat-free areas. The fatty area is located above the nasolabial folds and is the thickest part of the subcutaneous fat, with an average thickness of 0.8cm. The subcutaneous fat here is located in a triangular fossa surrounded by expression muscles, the upper boundary of which is the lower edge of the orbicularis oculi muscle, the inner boundary is the expression muscle of the upper lip, and the outer boundary is the zygomatic muscle. At the bottom of the fossa, the terminal branch of the facial artery, the upper lip artery and the branch of the buccal branch of the facial nerve pass through. In the fatty area, it is easier to form relaxation of the skin and supporting structures, causing changes in the contour of the facial soft tissue. According to the above anatomical characteristics, the fatty area of the cheek is the main site for facial fat aspiration. The temporal area and the area under the earlobe and mastoid are less fatty areas with only a few thin layers of fat distribution. There is almost no subcutaneous fat distribution on the surface of orbicularis oris muscle and orbicularis oris muscle, and the dermis and orbicularis fibers are directly connected, and there is almost little subcutaneous fat distribution on the surface of frontalis muscle, which is a fat-free area. The areas suitable for laser lipolysis treatment are mainly the face and some fatty areas such as fat pad. The face has dense distribution of blood vessels and nerves, thin skin, thin and superficial fat layer, and many subcutaneous fibrous tissues and supporting ligaments, so the conventional negative pressure suction is time-consuming and laborious, and if operated roughly, it is easy to produce complications such as hematoma and facial paralysis. The fat pad in the neck is located in the middle of the posterior part of the neck and protrudes from the neck, with different sizes, affecting the appearance. The fat pad is located in the middle of the posterior part of the neck and protrudes from the neck. The traditional surgical method is to make an incision at the edge of the fat pad protruding from the collar, cut the skin and remove the dense fat and fibrous tissue under the skin, which has a complete effect but leaves a long and obvious scar on the collar. With the progress of liposuction technology, negative pressure liposuction is also used clinically to treat the fat pad in the neck, but because of the dense composition of the fat pad there, the conventional liposuction operation is time-consuming and laborious. For the fat accumulation in the face and fat pad in the neck, if the laser lipolysis method is used to treat the fat pad, the damage is small, easy to operate and the effect is precise. Operation method: Before the operation, observe the local fat accumulation, and mark the suction area with contour style pen. Routinely disinfect the towel and expose the surgical field. Swelling anesthesia is injected locally using the swelling solution formula for conventional liposuction. Wait about 15 minutes after completion of swelling anesthesia to allow adequate local tissue swelling and capillary constriction. A small incision of 2-3 mm is made in the appropriate area and a laser cannula is inserted for treatment. The catheter is inserted through the incision into the subcutaneous fat layer, allowing the fiber to move slowly back and forth at a speed of about 5 cm/s. The catheter should always be kept in motion, and never pause for more than 20s at a point to avoid burning the skin. The energy of irradiation is about 10J/cm2, the total energy output varies according to the area, generally about 500~1000J for each side of the face, and about 2000~5000J for the fat pad, and the irradiation can be stopped when the local skin is warm to the touch of the fingers. After the completion of laser lipolysis, the melted fat will be extracted out of the body using negative pressure, using a 20ml disposable syringe connected to a 3mm diameter round-headed side hole fat aspiration needle, inserted into the subcutaneous fat layer from the incision, and perform fan-shaped uniform aspiration, the aspiration range is the same as the preoperative design. Note that the aspiration level is located in the superficial layer of SMAS, with the aspiration hole facing upward, and the movement is gentle, with smooth transition and no steps in the border area. The aspiration volume was estimated according to the preoperative estimate, and the aspirates from both sides were placed in separate measuring cups to facilitate comparative observation. Note the bilateral symmetry after aspiration. After surgery, the blood and swollen fluid accumulated in the cavity were squeezed out, and if needed Nd:YAG fiber could be inserted through the incision again to do fan scan irradiation for hemostasis and revision with a total energy of about 500 J. The incision was closed with one stitch of 70 Prolene suture or using no-sew adhesive tape, and the operative area was covered with multiple layers of sterile gauze and elastic self-adhesive bandage with pressure for 3 days, and the stitches were removed 7 days after surgery. Afterwards, we switched to wearing an elastic face mask for 1 month. After surgery, the contour and shape of the face were improved to different degrees, the abnormal bulge of fat pad basically disappeared, and the thickness of fat was significantly reduced by ultrasound examination, and there was no significant change with time. The skin laxity was also improved to different degrees, and the skin in the operated area was tighter and smoother than before surgery. Compared with conventional negative pressure liposuction, laser lipolysis-assisted negative pressure liposuction of the face has significantly less bleeding and is easier to operate, and both patients and operators are more satisfied with the results. Laser-assisted liposuction first uses the thermal effect of the laser to destroy and liquefy the fat cells, interrupting part of the fibrous tissue interval to facilitate the negative pressure suction thereafter, and finally suctioning out the fat tissue through negative pressure to reduce the local fat accumulation. The laser can effectively close the tiny blood vessels and reduce complications such as bleeding and postoperative hematoma. The laser can also stimulate the formation of local collagen and enhance the elasticity of the skin. Compared with traditional negative pressure liposuction, it has the following advantages: ①After laser irradiation, because the local fibers in the suction area are interrupted, the suction tube has less resistance during suction and suction is easier; ②Since some small blood vessels are closed, the intraoperative bleeding is significantly reduced; ③The effect is uniform, and the skin is not significantly uneven after surgery; ④It can promote skin contraction in the operation area; ⑤The postoperative recovery is fast, and there is no hematoma, nerve injury, fat The postoperative recovery is fast and there are no complications such as hematoma, nerve damage, fat embolism, etc. The inner diameter of the metal cannula used for laser lipolysis is 1mm, and the diameter of the suction tube used for negative pressure suction is 2-3mm, and the negative pressure instrument used is a 20ml syringe, which is minimally traumatic. The use of low negative pressure and fine syringe aspiration can effectively prevent excessive aspiration and damage to the facial nerve. It is important to note that aspiration should not be performed in consecutive pieces to prevent skin necrosis, which can be avoided with the fan-shaped interval tunnel aspiration method. Localized fat accumulation is usually accompanied by skin laxity and sagging. The process of aspiration with a small blunt needle is traumatic to the subcutaneous tissues, and during the healing process, the growth and contracture of fibrous tissues in the subcutaneous aspiration tunnel can tighten and retract the skin in the liposuction area. Laser-assisted fat aspiration has certain clinical application value and can achieve good results of debulking and plastic surgery. However, because of its small energy, it may require more operation time in large area liposuction due to the increase of area, so it is more suitable for the treatment of small areas such as cheeks, chin, neck and neckline, upper arms and calves. As a new method of treating local fat accumulation, laser lipolysis shaping is still in its initial stage, and the surgical indications and operation standards are not yet complete, and its surgical operation ways and methods deserve further exploration.