1. What is hair transplantation? Human hair can be transplanted just like other tissues in the human body. Hair transplantation is to cut the hair follicle around the part of the tissue through special instruments and complete, detached from the scalp in situ, and then transplanted to the need for hair and after a certain amount of preparation, with the conditions of accepting the hair position, called hair transplantation. Hair loss is caused by burns, infections, various types of trauma and alopecia areata (mostly in male patients), and leprosy can also cause hair loss. The donor area for hair transplants is usually the scalp. For eyebrow or eyelash defects that are not too extensive, the healthy eyebrow or nose hair can also be taken to repair the defect. The methods of transplantation include strip transplantation, small block transplantation, hole-punching transplantation, and various local flaps, subcutaneous tibial flaps, island flaps, free flaps, and prefabricated island flaps with blood vessels implanted in the hair-bearing area (secondary vascularized flaps). As long as the hair follicle is not damaged when cutting and transplanting, the blood supply of the tip of each type of flap is not damaged, the blood supply condition of the donor area is good and the correct plastic surgery operation is mastered, the transplantation will generally be successful. 2. What are the forms of hair transplantation? Hair transplantation can be single hair, multiple hair, strip hair transplantation, except that the scalp strip with healthy hair is subject to a certain length, width and size ratio restrictions, and island-shaped scalp flap transplantation with the tip of the flap is not subject to its length, width and size ratio restrictions, this method is mostly used for eyebrow reconstruction. 3. Hair drilling transplantation This transplantation is done by transplanting small pieces of skin with hair. It is suitable for male pattern baldness, scarring baldness, scarring baldness on the scalp after thermal and chemical burns, radioactive injuries and skin head lacerations. In the case of male pattern baldness, a hair line that has been mutually agreed upon with the patient is first drawn. Then the location of the drill hole to receive the graft is selected. The layout to which the grafts are transplanted should achieve the best results cosmetically, and should also take into account possible hair loss with age. For the band hair scalp site are generally selected hairy back hair or ear on the back side, because these areas are the least bald. 24 hours before the operation, within the hot water soap to wash the hair fully 2 times, remove the scalp on the oil, dander and dust. First, the hair donor hair cut off against the scalp, leaving about 0, 2 mm long stubble, in order to be able to identify the direction of hair growth, easy to anvil and subsequent transplantation reference. After routine local disinfection, local anesthesia was administered with 1%-2% procaine or 0,25%-0,5% lidocaine with an appropriate amount of epinephrine. A 3-mm diameter drill was used to cut the skin pieces. Care should be taken to drill into the scalp at an angle parallel to the direction of hair growth so as not to cut and damage the hair follicle and bulb. When drilling the skin piece of the hair supply area, it is necessary to leave sufficient spacing between the drill and the drill hole to prevent ischemic necrosis of the hair left behind. After taking a good, will be drilled at the hemostasis after sterile dressing bandage. 4, the donor area selection scalp piece cut in the area behind the ear is good, especially near the hairline is the best. Attention should be paid to the mainstream direction of the hairs pointing to the outer side, the hairs at the inner end of the reconstructed eyebrow are less skewed upward, and the outer end of the eyebrow is slightly downward. If the area of eyebrow hair loss is not large, it can be repaired by subcutaneous flap of the eyebrow hair on the same side or full-thickness skin slice of the opposite side of the eyebrow, and eyelash loss is suitable to be repaired by full-thickness skin slice of the eyebrow hair or nasal hair. How to prevent the transplanted hair from not surviving? First of all, the donor area should be selected with good hair quality and no skin disease. The surgeon should have a deep understanding of the direction of hair growth in different parts of the body, the approximate angle between the hair and the scalp, and then supplemented with special instruments, skillful techniques to cut the hair, so as not to damage the hair follicles. Secondly, the preparation of the area to receive hair transplantation, including cleaning, hot compresses and vasodilator drugs to improve local blood circulation, scar excision thoroughly or hair transplantation cavity size, depth appropriate to the transplantation of hair strains, bundles, strips of hair and the recipient area of the tissue tightly combined and pay attention to the prevention and treatment of infection is conducive to transplantation of hair to survive. Afterwards, the post-treatment of transplanted hair, such as protection and medication change, is also one of the important measures. 5. Indications and contraindications for hair transplantation All types of baldness, eyebrow, eyelash (especially eyelash) defects or beard defects, can be transplanted. Hair transplantation is not suitable when there is infection or insufficient local blood supply in the affected area.