First of all, human skin is mainly composed of epidermis, dermis and subcutaneous tissue.

The dermis is mainly composed of collagen secreted by fiber precursor cells, and the collagen fibers that make up collagen are arranged neatly, keeping the skin smooth, shiny, elastic and tough. However, under all kinds of trauma or infection, the collagen fibers that were originally arranged in order began to shrink, disorder, accumulate and even break, and new capillaries and nerve fibers grew into connective tissue. The dislocation and regeneration of collagen fibers make the healed skin uneven, damage the blood circulation of the skin unstable, and damage the pigment changes of the skin.

The surface layer of skin can be repaired by the basic cells of epidermis, but it will also cause color changes, and it is difficult for the skin to return to its original shape and color. In this way, uneven scars and color changes will be formed.

For postoperative scars, the factors affecting their formation mainly include the following aspects:

1, skin tension

Including the external tension caused by the degree of skin tissue defect and the inherent tension of skin tissue itself. Hypertrophic scars tend to occur in areas with high tension and activity, such as joints.

2. Age

People with vigorous tissue growth and strong post-traumatic reactivity are more likely to form hypertrophic scars. This is different from what we have always thought that scar healing in the elderly is not as fast as that in young people. Young people, especially 10-20 years old, have the highest rate of hypertrophic scars.

3, skin pigment

Colored people have more pigment cells and are easily stimulated. The incidence of keloid in blacks is nine times that of whites. It is also more likely to occur during the physiological activities of the pituitary gland, such as adolescence and pregnancy.

4, infection or foreign body

Repeated infection or tissue reaction caused by foreign body residue can lead to excessive proliferation of granulation tissue, which is prone to hypertrophic scar or keloid.

5. Other factors

The angle between the incision and the skin, the depth of the wound and the healing time will all affect the formation of postoperative scar.

During the operation, in order to avoid postoperative scar hyperplasia, what can be done is to reduce the tension on wound healing. This scale is not the so-called "beauty line" that is often said.

Clinically, surgical sutures are mainly divided into absorbable sutures and absorbable sutures. Absorbable suture can be absorbed by tissue without suture removal after operation, and can be divided into catgut suture, chemical synthetic suture and pure natural collagen fiber suture according to different materials and absorption degree. Non-absorbable suture refers to suture that cannot be absorbed by tissue and needs to be taken out after operation. The time of suture removal also varies with the suture site and wound condition.