Surgical indications Not all pigmented nevi on the face need surgical treatment, and surgical excision can be considered in the following cases: ① Preliminary determination of junctional nevi, or those with precursor symptoms of malignant transformation, such as color change, lesion expansion, bleeding and inflammatory changes, etc. ② Those with large scope, rough surface, nodules, long hair, etc. affecting the appearance. Excision and suturing is suitable for facial junctional nevus, intradermal nevus, mixed nevus with small area and pigmented nevus that can be sutured directly after excision. Take the forehead nevus excision suture procedure as an example, the following is an introduction. A shuttle-shaped incision is designed on the normal skin around the nevus, and its long axis is in line with the skin line. The skin tissue involved in the pigmented nevus and a small amount of normal subcutaneous tissue are removed in a wedge shape so that the incision is relatively flat after suturing. If the nevus is small in size, it can be directly sutured intradermally with 3/0 non-absorbable thread. Then use 5/0 non-absorbable thread for interrupted skin suture. If the nevus area is larger, subcutaneous subcutaneous separation and reduction of tension can be made on both sides of the incision margin, and then divided into two layers of dermal subcutaneous and skin sutures [1]. Points to note: (1) The incision should be 1~2mm away from the peripheral edge of the nevus pigment visible to the naked eye to avoid incomplete excision and local recurrence. (2) The pathological tissue and part of the normal subcutaneous tissue should be excised in a wedge shape, so that the incision is tightly dovetailed and the surface is flat after suturing. (3) For larger intradermal nevus, if the suture cannot be pulled together in one complete excision, it can be excised in several surgeries, and the interval between two surgeries is usually 3-6 months. Complications and prevention Common complications are incision infection and splitting. Care should be taken to follow aseptic and non-invasive operation techniques during surgery and avoid suturing the incision under excessive tension. Excisional skin grafting Applicable to various types of pigmented nevi with wide area, which cannot be directly sutured after excision or may cause secondary displacement deformity and dysfunction of adjacent organs after direct suturing. The following is an example of excisional skin grafting for right temporal facial nevus. The excision area was drawn with methylene blue, and the nevus of the temporal nevus was preserved so as to be proportional to the contralateral temporal nevus. Local infiltration anesthesia was performed with 0.25% to 0.5% lidocaine solution (containing epinephrine 1:200,000). The pathological tissue was excised as designed, and the wound was hemostatic with electrocoagulation or ligation. A full-thickness skin slice or a thick medium-thickness skin slice is cut and placed on the trauma surface. Under normal skin tension, the skin slice is interrupted with 5/0 non-absorbable suture around the trauma edge, leaving a long thread to pack. The skin piece is covered with a layer of petroleum jelly gauze, then gauze and shredded gauze are used to fix the skin piece by packing and pressure method, and finally it is fixed by cotton pad and bandage with pressure. Points to note: (1) Since the change of color and texture after skin slice transplantation can affect the post-implantation effect, therefore, for blue nevus with light pigmentation, excision of skin slice transplantation should be taken with caution. (2) Generally, if the pigmented nevus involves the whole layer of skin or the superficial layer of subcutaneous tissues, a better result can be obtained by removing the pathological tissues completely and then repairing with skin slice transplantation. Sometimes, pigmented nevus invades deep subcutaneous tissues, if the pathological tissues are completely removed, the deep important nerves (such as facial nerve) may be damaged, and the secondary deformities such as depressions are often caused by applying skin slice repair, in this case, the appropriate deep pathological tissues can be retained without removal, and skin slice repair can still be applied. (3) Careful hemostasis of the wound is required to prevent the formation of hematoma under the skin slice after surgery to affect the viability of the skin slice. Complications and prevention: subcutaneous hematoma, skin slice displacement, infection resulting in skin slice necrosis. Therefore, intraoperative hemostasis should be complete, and attention should be paid to all aspects of packing, compression and braking of the transplanted skin pieces.