Follicular Unit Hair Transplant Method

Background

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.

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). The groupings are removed from the donor area by an elliptical excision and are carefully dissected using appropriate lighting and magnification. 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.

Problem

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.

Epidemiology

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.

Etiology

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.

Indications

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.

Comparison of donor densities. Left donor has 72 follicular units per cm2; right donor has 134 units per cm2.

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.

Contraindications

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.

Medical Therapy

Minoxidil and finasteride are approved by the US Food and Drug Administration (FDA) to treat male-pattern hair loss. Minoxidil is the only medication approved for the treatment of female-pattern hair loss. Both medications are more effective for patients with earlier stages of hair loss and are excellent treatment options for patients who are losing hair but who are not candidates for surgery. The key to success with each medication is compliance. Six to 12 months can elapse before medications begin to work.

For patients who are candidates for surgery, continuing medical treatment often helps increase the density of transplanted hair by slowing down the rate of loss of existing hair and increasing the caliber of existing and transplanted hair. Medication usage should not alter candidate selection, the hairline design, or the distribution of transplanted hair. In all patients, the physician must assume the patient may stop taking the medications sometime in the future and must determine the cosmetic impact this would have on the transplanted hair.

Finally, a variety of over-the-counter products purport to treat male- and female-pattern hair loss. Few to no independent, peer-reviewed studies support their safety or efficacy.

Preoperative Details

Planning and design

The midpoint of the frontal hairline is designed to fall approximately 8-9 cm above a horizontal line drawn through the center of the patient's eyebrows. Then, the hairline is gently curved laterally and superiorly toward the temporal lateral fringe. This curvilinear portion of the hairline may rise gently above, but should not be designed below, the horizontal plane. Depending on the existent lateral fringe, the hairline may be connected to this temporal fringe.

Intraoperative Details

Donor area

All patients should be aware before surgery that a permanent scar will result from removing the donor ellipse. For the vast majority of patients, the scar is of no practical concern. If a patient wears his or her hair at least 2 cm in length, the existing hair will camouflage the scar.

The donor region is the only limiting factor in hair transplantation. For the majority of transplants, the donor hair is harvested via a surgical ellipse. The length and width of the ellipse is a reflection of the number of grafts needed for the surgery and the patient’s donor density. The average donor density is 80-90 follicular groupings per cm². To increase the number of grafts, make the ellipse longer rather than wider. Ellipses wider than 1 cm have an increased risk of creating a wider or even hypertrophic scar. As an example, if 1000 grafts are needed and a patient has average donor density, an ellipse of 14 X 0.8 cm will provide approximately 1000 grafts.

The donor ellipse is removed with the patient under local anesthesia and in the prone position. Staples or sutures are left in place for 7-10 days.

Graft dissection

Once the donor tissue has been removed, it is kept in chilled saline over frozen packs to maintain a cool temperature while the tissue is dissected. To maintain graft viability, the grafts must not become dehydrated or heated. The grafts are dissected using a binocular microscope at a minimum magnification of 10X.^[8] Sterilized tongue blades placed over an autoclavable glass cutting plate create a cutting surface for the tissue. Assistants use jeweler's forceps to apply traction while cutting with a standard double-edged razor blade or knife. Donor tissue first is reduced to thin wafers or slivers containing only a few follicular units. Then, these slivers are cut into follicular units and trimmed of excess bald tissue.

Donor ellipse and sutured donor site.

The use of magnification and a polarized light allows minimal transection of follicles during the dissection process and dense packing in the recipient area. The ability to create greater density within the recipient zone as a result of the small size of the grafts is the key to follicular unit hair transplantation. The dissection process is undeniably the most labor-intensive portion of the process and requires 2-3 graft-dissection assistants for every one implanting assistant.

Graft implantation

During the implantation stage, the follicular unit grafts are placed into the anesthetized recipient sites created by 19- to 22-gauge needles by using microvascular forceps. A goal of 20-30 follicular unit grafts per cm² is reasonable and readily achieved by skilled assistants.

Margin of donor ellipse and follicular unit micrografts of 1, 2, and 3 hairs

Postoperative Details

Once the implantation process has been completed, the recipient surface is cleaned using chilled saline spray. The use of a postoperative dressing helps protect the grafts as they heal overnight.

Patients are able to resume regular activities immediately but should avoid heavy exercise for at least 3-4 days after surgery. Patients can remove the dressing at home the morning after the procedure. Some perifollicular hemorrhagic crusting can be seen at this point, and it remains for 5-8 days. Patients are instructed to shower but should not try to pick off their scabs. The majority of patients with existing hair return to work after 2-3 days without any cosmetic problems. The staples or sutures are removed in 7-10 days. The transplanted hair should begin to grow 3-6 months after surgery and should be fully grown in 12 months.

Pattern VI alopecia before and after follicular unit micrografting.Dorsal view of pattern V alopecia before and after approximately 2000 follicular unit micrografts.Eyebrow transplantation. Left is preoperative. Right is after 400 follicular unit micrografts.Close-up view of frontal hairline before and after micrografts.

Complications

Medical and surgical complications are rare and, if they occur, are seldom threatening. Postoperative bleeding and infections are unusually rare. Donor suture lines occasionally may spread and are more prone to do so if closure is performed under tension. Transient folliculitis or pruritus may occur.

The majority of complications arise from poor hairline design, poor technique, and, most commonly, unrealistic patient expectations.

Outcome and Prognosis

The goal is to make the final product look so natural that it cannot be distinguished as a transplant. The tight packing of grafts provided by microscopic dissection generates a natural appearance acceptable to most patients. Although this method is time and labor intensive, the results justify the meticulous attention to detail.

Source :medscape.com