Hair Replacement Surgery

Mark M. Hamilton

Tremendous progress has been made in hair restoration over the half-century since its introduction. What a great step forward for men and women with hair loss it was when Norman Orentreich introduced the concept of hair transplantation in 1959.¹ Yet the field of hair restoration has had to overcome the reality of the initially effective yet so very unnatural results. Fortunately, progress has brought this field to an era where dramatic results are possible with the most natural of appearances. This chapter will review some of the essential features that allow results not possible as recently as a decade ago.

♦ A Brief History

The first hair transplant procedures involved use of grafts (or plugs) of 15 to 20 hairs each. These grafts were able to relocate large amounts of hair but were completely unnatural. Even today, patients are concerned about having a “doll’s head” appearance. Over the ensuing decades, however, grafts became progressively smaller until minigrafts and micrografts became the state of the art in the 1980s.²^,³ With this decrease in graft size came a more natural result and an increased acceptance of hair transplantation.

Probably the two most significant advances of the past 20 years have been follicular unit grafting as well as incisional slit grafting.⁴ These techniques combined have brought hair transplant to the point of achieving the most natural results possible today. Both will be discussed in greater depth later in this chapter.

Other procedures commonly used in hair restoration in the past, but much less so today, include scalp flap procedures as well as scalp reductions. Scalp flap procedures were most often either a Juri flap⁵ or a variant of this. These flaps allowed the transfer of a large amount of hair with one flap providing almost immediate results. Their downsides, however, were many. The hairline created was abrupt and unnatural, the scars long and difficult to cover, and the procedure itself technically challenging and of moderate risk. With the improvements in hair grafting techniques, these flaps have become rarely used.

Scalp reductions offered the promise of removing large amounts of hairless scalp, particularly in the crown, without decreasing the amount of available donor hair. The downsides of scalp reduction, however, soon became obvious.⁶ These included scarring, creation of unnatural hair growth patterns (slot formation), stretch back, and a decrease in donor density. Again, with improved grafting techniques, their use has been limited.

♦ Patient Evaluation

The initial consultation is the time where patient selection occurs as well as where a treatment plan is made. An important part of this is an in-depth analysis through a focused history and a physical exam.

The vast majority of hair loss in men is due to androgenetic alopecia. This is recognized by the classic pattern and progression as well as a family history. In most women, the cause is not always so clear-cut but is most often of genetic origin as well. In the cases in both men and women where the cause of hair loss is not obvious, a more detailed history, physical, and workup should be considered.

A good starting point is to consider alternative causes of hair loss. These include fever as well as stress, both of which would be associated with an acute onset and fairly rapid progression. Endocrine disorders such as hypothyroidism and hormonal changes (pregnancy/menopause) may also lead to hair loss. Other causes include nutritional deficiencies (especially iron), chemotherapy, as well as recent infection. A review of current medications may reveal one that is associated with hair loss. These include β-blockers, oral contraceptives, hypercholesterolemia medications, as well as Coumadin (crystalline warfarin sodium; Bristol-Myers Squibb, New York, NY).

Scarring is another common cause of hair loss. Most often, this is due to previous cosmetic surgery as seen with facelifts or forehead lifts. Other sources of scarring include lichen planopilaris and discoid lupus.⁷

Traction alopecia is seen with hairpieces or hair weaves. This occurs gradually over time in the areas of greatest tension and is usually obvious to the patient. This is a strong argument for these patients to move forward with hair transplantation to lessen the progression of their hair loss.

Alopecia areata is an unusual autoimmune disorder that results in distinct patches of hair loss that change over time. History as well as scalp biopsy can confirm the diagnosis. Medical treatments of some benefit exist. Fortunately, however, for most the condition is temporary and resolves over time. Another unusual cause of hair loss is trichotillomania. This is an obsessive compulsive disorder where repetitive pulling of hair leads to hair loss.

The workup of hair loss may include some or all of the following tests: complete blood count, electrolytes, antinuclear antibody, VDRL (Venereal Disease Research Laboratory), ferritin and iron levels, thyroid hormone levels and thyroid stimulating hormone, and testosterone and dehydroepiandrosterone levels. A scalp biopsy as stated above may be useful.

♦ Nonsurgical Treatments

Men as well as women have continually been bombarded with alternatives to surgical approaches, most of which have limited value. These include oral medications and topical treatments as well as hairpieces. Of all the medications and supplements available, only two, minoxidil and finasteride, have a proven history. Minoxidil’s hair growth benefits were discovered during its use as an antihypertensive. It has now been used as a topical treatment (Rogaine; Upjohn, Kalamazoo, MI) for more than 2 decades. It can be used by both men and women. Minoxidil is available in a 5% concentration over the counter. Minoxidil limits hair loss primarily in the crown with little benefit along the frontal hairline. In addition, its ability to stimulate hair growth is limited. Most find the application time consuming and cumbersome. Given the modest results, it has developed limited popularity.

Of more benefit is finasteride (Propecia; Merck, White-house Station, NJ). Finasteride is taken orally once daily. It acts as a 5-α reductase inhibitor decreasing the concentration of dihydrotestosterone at the hair follicle. Its use is indicated only in men. Studies have shown that 9 out of 10 men will see some results. Two thirds will see visible regrowth. The combination of ease of use with minimal side effects and a fairly effective result has made finasteride the gold standard for medical treatment of hair loss.

Low-level light (laser) therapy is a promising yet poorly understood or documented phenomenon. These technologies do seem to have the ability to stimulate hair growth and sometimes quite dramatically. Most of these realized successes, however, have been reported through personal communication or advertisements. Large multicenter studies will be needed in the future to document expected results and define what role this technology will play in hair rejuvenation.

♦ Patient Selection

An important part of creating a treatment plan is determining expected future hair loss. A detailed family history can be helpful. Because androgenetic alopecia is genetically based, extent and pattern of hair loss in other family members can serve to estimate where the patient may go over time. In addition, a patient’s recent history of hair loss can be used to estimate future progression. A rapidly balding patient with extensive hair loss in his father, a grandfather, and a brother will want to take a more conservative approach. A patient with a stabilized hair pattern for 10 years and no family history can take a more aggressive approach.

Age obviously plays a role here as well. Young patients, no matter what the history, need a more cautious approach. Rarely should a patient under 20 years of age undergo a transplant procedure. In older patients, hair loss is often stabilized or if still progressing a final pattern can be more easily predicted.

Physical exam of the patient will reveal several important considerations, including classification of hair loss, extent of donor hair, quality of hair, as well as skin/color similarity. A variety of classification systems have been put forth to quantify hair loss with the most common being the Nor-wood system.8 This system rates the patient’s extent of hair loss from 1 to 7, with 7 being the most advanced.

Extent of donor hair is the primary determinant of how much transplantation can be done at the present time. This is partly determined by extent of hair loss as in the Nor-wood classification. It is also determined by the hair density of the donor region. This can be decreased in patients with previous transplantation or in those with diffuse thinning, such as seen in female hair loss.

Hair quality is another important factor.⁴ This includes a variety of factors such as hair density, the texture of hair, hair color, and curl. Ideal patients would have coarse curly hair of a lighter color and high density. Fine, sparse hair that is straight and dark would in general be the least ideal.

A similarly related factor is skin color and the contrast it provides to the patient’s hair color. In general, less contrast is better. Matching of skin and hair color is ideal. Think dark hair and how visually better this would be on dark skin versus light skin.

♦ Important Numbers

Numbers play an important role in planning for hair transplantation. It is important to keep several in mind. On average, a full head of hair has 100,000 hairs. Each follicular unit on average has around 2.1 hairs, so there are ˜50,000 follicular units on a full head of hair. Approximately 25% of these follicular units (12,500) are in the occipital donor area of the scalp. In general, one half or 6250 follicular units can be harvested before there is noticeable thinning or distortion of this area.⁹ Also, on average, each square centimeter of donor tissue contains 100 follicular units.

If transplanting a completely hairless area, the total number of grafts can be calculated based on measurements and use of the above numbers. If there is 5 cm 10 cm, then the total area will be 50 cm 2. Without any balding, this area would contain 5000 follicular units. To achieve coverage in this area where thinning will not be visualized, more than half, or 2500 or more follicular units, must be transplanted.

♦ Donor Harvest

A variety of techniques have been used over the years to obtain donor hair. At the present time, harvesting of grafts through an elongated fusiform excision is the procedure of choice. The area for the hair to be harvested is first marked out with a skin marker. This is typically done in the occipital area at or above the external occipital protuberance. Hair can also be harvested from the temporal area as an extension of an occipital incision or on its own. Length and height are determined based on the number of grafts needed and scalp laxity. In general, 100 (around 200 hairs) follicular units can be harvested from 1 cm² of donor scalp.¹⁰ Depending on scalp laxity, donor strips can be anywhere from 8 to 15 mm in height. In my practice, donor strips are created ˜1 cm in height to help minimize tension and improve donor scars. If 1500 grafts are needed and the patient has good donor density, a 15- × 1-cm excision would be designed.

Once the donor strip is marked, hairs in this area are shaved to around 2 mm in height and the hair above is taped up. The area is anesthetized by first injecting slowly and in small amounts with 1% lidocaine with 1:100,000 epinephrine through a 30-gauge needle. Once adequately anesthetized, tumescent injections are performed to improve ease of dissection. Tumescence helps to lift the donor strip from the underlying tissue minimizing the chance for vascular or nerve injury. Although not typical, we do prepare and drape the donor area.

The donor strip is harvested with a standard no. 15 blade beveled in the appropriate fashion. The strip is taken in a subcutaneous plane preserving some tissue below the hair follicles. It is immediately placed in iced saline solution. The donor site is first approximated with towel clamps and then closed with interrupted as well as running locking 3-0 Prolene suture (Ethicon, Somerville, NJ).

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