Follicular unit transplantation

Follicular Unit Transplantation (FUT) is a hair restoration technique where a patient's hair is transplanted in naturally occurring groups of 1 to 4 hairs, called follicular units. Follicular units also contain sebaceous (oil) glands, nerves, a small muscle, and occasional fine vellus hairs. In Follicular Unit Transplantation these small units allow the surgeon to safely transplant thousands of grafts in a single session, which maximizes the cosmetic impact of the procedure.

FUT is considered an advance over older hair transplantation procedures that used larger grafts and often produced a pluggy, unnatural look. In a properly-performed follicular unit transplant, the results will mimic the way hair grows in nature and will be undetectable as a hair transplant.

Follicular Unit Transplantation uses follicular units to accomplish a number of objectives critical to the hair restoration process:

Since the follicular unit is a distinct anatomic and physiologic entity, preserving it intact during the graft dissection is felt to maximize growth. In FUT, after hair is removed from the back of the scalp in a single strip, stereo-microscopic dissection allows the individual follicular units to be removed from this strip without being damaged.

In the older mini-micrografting techniques, hair was harvested in multiple strips with the follicular units in each strip edge showing damage from the harvesting blades. The strips were then cut into smaller pieces, a process that would break up follicular units and risk additional damage to the follicles.

Follicular Unit Transplantation enables the hair transplant to look natural both at the individual follicular unit level and in regards to the overall graft distribution. Since scalp hair normally grows in follicular units of 1 to 4 hairs, the exclusive use of these naturally-occurring units in FUT ensures that each graft will be identical to the surrounding follicular units. Thus, when the transplanted follicular units grow hair after a transplant, the overall results of the transplant will appear natural.

Additionally, by using individual follicular units, rather than larger grafts, the surgeon has a greater total number of grafts with which to work. This allows the surgeon to distribute the grafts more evenly over the scalp for a more natural overall distribution of hair.

The density of naturally-occurring follicular units in a normal scalp is relatively constant, measured at approximately 1 unit per mm². This helps in the planning of a hair transplant in two ways:

In patients with high hair density, there are usually a sufficient number of follicular units in the donor area to accomplish the patient's goals. However, in the patient with low hair density, a compromise must be made - and this is guided by the follicular unit constant. By transplanting a patient with low hair density using the same number and spacing of follicular units as in a patient with high density, the transplant surgeon will produce a thinner look, but will allow proper conservation of donor hair for future procedures.

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