Follicular Unit Hair Transplant Method 

From the 1960s into the mid 1990s, transplanted hair appeared unnatural because surgeons used unnaturally large-appearing hair grafts consisting of 10-25 hairs each. That era is over. Hair naturally grows in 1-4 hair follicular groupings. In the early 1990s, surgeons began switching from using unnatural-appearing hair "plugs" (10-25 hairs) to using consistently natural-appearing hair follicular groupings (1-4 hairs). In current practice, all women and men should expect consistently natural-appearing transplanted hair.^{[1, 2, 3, 4, 5, 6]}

Follicular unit transplantation is the redistribution of naturally occurring follicular groupings from the posterior scalp (donor region) into the region of thinning hair in the midfontal scalp (recipient sites).^[7] The groupings are removed from the donor area by an elliptical excision and are carefully dissected using appropriate lighting and magnification.^[8] The donor tissue is separated into follicular units, which are then reimplanted into recipient sites created by 19- and 20-gauge needles. The sites are carefully created between thinning existing hair and in a distribution that will look natural 1-20 years after surgery.

Follicular unit transplantation is the standard surgical technique to treat male- and female-pattern hair loss. Follicular unit transplantation is also used to correct unnatural-appearing pluglike transplants, repair eyebrows, and redistribute hair in persons with inactive scarring alopecias.

Hair frames the face. The length, style, and color of hair often reflect how people see themselves. The slow involuntary loss of hair over the years impacts how the world perceives an individual and, more importantly, how individuals see themselves. Involuntary hair loss can have an emotional impact on an individual that ranges from minimal to profound. With medication, hair transplantation, or both, a natural frame of hair can be maintained or restored in patients with male- and female-pattern hair loss.

Male- and female-pattern hair loss are polygenetic disorders of unknown etiology. The precise genes involved remain unknown. The age of onset and the rate of hair loss vary from patient to patient. Some patients lose all their hair in their early 20s, while others’ hair gradual thins over decades. Family history of hair loss does not necessary determine the pattern of hair loss in each individual.

Frequency

Male-pattern hair loss affects approximately 50% of all men, and female-pattern hair loss affects approximately 30-40% of all women. The rate of loss and extent of loss vary from patient to patient.^[9]

The etiology of male -and female-pattern hair loss remains unknown. Some consider it to be a polygenetic disorder from both parents. It has not been associated with any particular diet, hair style, or infection.

As with all surgical procedures, appropriate candidate selection is vital to the success of the procedure. Persons with any hair color type or skin type are candidates. Key factors to consider in candidate selection include donor density in the posterior scalp, caliber of hair, extent and rate of hair loss, and realistic expectations.

Donor density

Most patients have 60-85 follicular groupings per cm². Patients with a higher density are able to receive more grafts than those with below-average density with an equal-size donor ellipse. The number of grafts needed during a surgery is a reflection of the size of the recipient zone.

The scalps of white persons have approximately 100 units per cm². The units average approximately 2.3 hairs each; therefore, in white persons, the average scalp has approximately 230 terminal hairs per cm². Blacks and Asians have significantly lower densities of both units and hair compared with white persons. See the image below.

Caliber of hair follicles

The caliber of a patient’s hair follicles plays a vital role in the perceived density a transplant can create. A man or women with fine, thin hair will produce fine and thin transplanted hair, while a man or woman with coarse, wavy hair will create thick-appearing transplanted hair.

Extent and rate of hair loss

In an era in which male- and female-pattern hair loss can be halted with minoxidil and/or finasteride (for men), transplantation should only be performed in patients who have enough space between thinning existing hair follicles to create a recipient site and place a graft.

The net perceived density of a hair transplant is equal to the number of hair follicles transplanted minus ongoing hair loss. All patients must understand that ongoing hair loss will affect the perceived density of the transplant. While often successful, medications for hair loss are elective. The design and distribution of a hair transplant must assume ongoing hair loss and how it will impact the density and cosmetic appearance of the transplant. An estimation of how many procedures will be needed to achieve a short- and long-term natural-appearing transplant should be discussed during the initial consultation with the patient.

Realistic expectations

The most common complication from a transplantation is failed expectations. The physician must create realistic expectations during the consultation. Factors such as donor density, caliber of hair follicles, and rate of hair loss will help determine realistic expectations.

Hair transplantation should not be performed on a patient with unrealistic expectations. In addition, patients taking blood thinners should not undergo hair transplantation. Finally, any patient with an active medical condition that may interfere with the procedure should obtain medical clearance.