Hair transplantation is a surgical procedure in which hair is removed from the back and/or sides of the scalp (donor area), to be transplanted, follicle to follicle, to areas that have thinning hair or bald – on the front, top, or crown of the scalp (recipient area). Because the donor area has different characteristics and the hair is permanent, once transplanted, it will continue to grow for a person’s lifetime.
How do hair transplants work?
Even extremely bald men still have a ring of hair around the back and sides of their heads. This hair is not lost during the balding process because the follicles themselves are not affected by DHT, the hormone that causes the follicles in the front and top of the head to shrink in size and stop growing hair (see What is DHT?).
In hair transplantation surgery a piece of this skin containing these follicles is removed from the back and sides of the head. The follicles are then extracted from the surrounding tissue and then are reinserted into the balding areas of the scalp.
Since the follicles themselves are not affected by the hormone DHT, they continue to grow hair even after they have been moved from the back of the head to the front of the head.
In most cases doctors will concentrate the placement of the hairs to the front and top of the heads at the expense of the crown because this frames the face and give the best aesthetic result.
Unless patients use a drug like Propecia after having a transplant, they will continue to see an increase in hair loss from the non-transplanted hairs that were growing there before the transplant. In this case additional transplant procedures may be performed to increase the density. Due to the limited amount of skin that can be removed at one time, 2,500 grafts is usually the most that can be done in a session.
While it is impossible to have the same density that existed before the hair loss, with careful placement of the follicles by the doctor, the illusion of a full head of hair can be created with a hair transplant.