The two main methods of hair transplant surgery that are used today are called Follicular Unit Transplantation (FUT) and Follicular Unit Extraction (FUE). The main difference between them is in harvesting hair follicles. The FUT is the older method, using strip harvesting, when a linear strip of skin of up to 20 centimetres long and 1.5 centimetres wide is extracted from the back of the scalp and the opening is then sewn closed. This strip is then placed under microscopes and dissected into small grafts, containing just one follicular unit each. Such follicular grafts are then implanted into the bald area. The strength of this method is its high yield, measured as a percentage of the follicles that are successfully transplanted into the bald area. This yield is around 98%. The greatest weakness is that it leaves the patient with a linear scar at the back of the head. The FUT is less expensive than the FUE and is used when a large bald area needs to be filled with transplanted hair in one single session.
The FUE technique uses a micro extraction technology to harvest individual hair follicles that can be directly implanted into the small needle poke holes in the bald area. The FUE method is the latest technology, introduced only in 2002. Its greatest benefit is the fact that it leaves the patient with only tiny scars at the back of the head, which are barely noticeable, and the healing time is much shorter than with the FUT, due to the small size of the wounds. However, this technique cannot be used to cover large bald areas in one session and it is more expensive. Additionally, its yield is much lower, due to the transaction of many hair follicles, and since the supply of donor hair is limited, it cannot be used in patients whose baldness has progressed above NW4 level.
Potential future surgical hair restoration technologies, such as hair cloning and the generation of new hairs in wounds, should help solve the constraints with the limited amount of donor hair. It seems that hair transplantation will in the long future only be used for frontal hairlines and, therefore, the follicular harvesting should manage to provide a sufficient supply of hair implants. However, none of the aforementioned potential future technologies is expected to become commercially available before 2013. Therefore, the immediate future probably lies in improving the harvesting techniques of the FUE in order to improve its yields and make it financially more affordable. The FUT with its strip harvesting, which started a revolution in the hair transplantation industry less than two decades ago, may become history in the not too distant future.