Hair restoration is an art and a science that requires an experienced and dedicated surgeon and team to achieve consistently superior outcomes. In addition to discussion of local anesthetic in use for hair restoration, this article emphasizes the pearls and pitfalls that are involved at every phase of the procedure including judgment, hairline design, donor harvesting, recipient-site creation, graft preparation, and graft placement. Two recent advances in the field are highlighted: the use of regenerative medicine (platelet-rich plasma and ACell), and developments in follicular-unit extraction as an alternative to traditional linear donor harvesting.
Key points
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The surgeon should understand the natural Norwood hair-loss patterns so as to recreate natural patterns.
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The surgeon should have thorough knowledge of dermatologic conditions that preclude surgery, such as scarring alopecia, and also be well versed in the medical management aspects of hair restoration, such as the use of finasteride and minoxidil.
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The surgeon should understand the principles of good hairline design and the objective of framing the face for aesthetic purposes.
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The surgeon should be technically well versed in recreating the natural angle and direction of recipient sites according to the specific region of the scalp.
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The team should be excellent at both graft preparation and graft placement, and be aware that inferior performance leads to devastating outcomes.
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The surgeon should be a lifetime student, learning new techniques by attending workshops and major conferences as well as reading and analyzing his own work.
Introduction
Hair restoration has advanced remarkably since the bygone era of unnatural “plug” grafting. Nevertheless, despite the use of follicular-unit grafting, bad results persist because of technical errors, lack of judgment, and poor artistry. Many plastic and cosmetic surgeons look askance at hair transplantation because it is thought of as an easy procedure to master, which is absolutely not the case, or that it can be taxingly boring and tedious, which is an erroneous perception. Hair restoration, when mastered, can be an extremely rewarding procedure for both the patient and surgeon alike. In this author’s opinion hair transplantation is thoroughly enjoyable because artistically designed patterns can be created that fit a patient naturally, will age well for him, and have been created in such a way that provides optimal visual density for the number of grafts transplanted. Besides outlining the fundamentals of what every surgeon should know when performing a hair-transplant procedure, this article also discusses some of the major advances in the past several years in hair restoration, including regenerative medicine (the use of platelet-rich plasma [PRP] and ACell [Acell Inc, Columbia, MD]), and follicular-unit extraction (FUE) methods that obviate a linear scar. Hair transplantation can be undertaken with any level of anesthesia, but because it is essentially a skin-based surgery it can be easily performed from start to finish under local anesthesia only.
Treatment goals and planned outcomes
Before outlining what is surgically necessary, the larger scope of understanding the nature of male pattern baldness (MPB) is critical. Discussing every type of hair loss lies beyond the scope of this article, so the focus here is on the principal type of hair loss, MPB. Many surgeons are overzealous to begin their career in hair restoration without this prerequisite knowledge, and this can be a great disservice to the patient who may encounter a serious problem perhaps not today but in a decade, when the hair-transplant result that originally looked natural now cannot be fixed as a consequence of poor or absent judgment.
The best way to explain the nature of MPB is that hairs transition from thick “terminal” hairs slowly over time into thin, wispy, “vellus” hairs that in turn ultimately disappear altogether to leave a bald pate. Medications such as oral finasteride and topical minoxidil, along with laser technology, are useful if not in fact particularly important in slowing down this process, and any male patient who is in the early process of hair loss should be counseled vigorously on the importance of medical management to slow down and partially reverse hair loss, and perhaps avoid the need for surgical intervention, at least for the present. Finasteride and minoxidil are synergistic in their benefit and should be considered better together than either alone; they work toward slowing down the conversion of terminal hairs to vellus hairs and also retard the conversion of vellus hairs to absence of hairs, and finally help reconvert hairs from vellus hairs back, at least partly, to thick terminal hairs. Their biggest drawback is that once patients stop taking these medications, they lose all the hairs that were preserved during the time they were taking them. Despite this limitation, it is important to counsel every man who is experiencing hair loss about how potent these medications are, and also on the patient’s suitability as safe candidates for surgery, something that demands further explanation.
The reason that young men (eg, early to mid-twenties) may be unsafe as candidates for hair transplantation is that they may lose more hair over time and not have a sufficient supply of donor hair in the occipital region to cover further hair loss over the longer term. It is a losing battle of increasing demand for hair and an ever dwindling supply of donor hair, owing to either further balding or use of the donor hair for transplantation. Taking a step back to explain the preciousness of donor hair may be important here. Norman Orentreich discovered in the 1950s that hair taken from the baldest man (think of a horseshoe configuration in the occiput) and transplanted to the front of the scalp retains the genetic characteristics of the native donor region; that is, it will not be lost after being moved to the front of the head. However, for young men who are losing hair one cannot predict with absolute accuracy how much donor hair is actually safe to transplant and how their hair loss will progress. At this point the surgeon with experience use considered judgment to prognosticate if there will most likely be enough donor hair to address both present hair loss and additional demands for future transplants going forward. Furthermore, it is important that every budding hair-transplant surgeon also takes the time to review dermatologic conditions that can mimic MPB but that may in fact represent nontransplantable conditions such as scarring alopecia, especially if the physician is not a dermatologist by training.
Preoperative planning and preparation
When planning to perform a hair-transplant procedure, the surgeon should keep in mind the aforementioned tenets of whether the patient has the proper hair density, usable donor hair, and degree and area of baldness, along with the age of the patient. In addition, it is important to look at how much hair is on the verge of being lost (ie, are miniaturized or vellus in nature) and may need surgical correction to avoid a problem in the near future of progression of hair loss in that area. The curlier and thicker the hair, the greater the impact the hair-transplant result will be. Furthermore, if the color-to-contrast ratio of scalp to hair is minimal (eg, dark scalp and dark hair or light hair and light scalp), the patient will also potentially have a much improved outcome of visual density because the underlying bald scalp will be less apparent. These factors will all be evaluated by an expert physician when determining the successful outcome of a procedure. Every prospective surgeon should review the Norwood-Hamilton (N-H) scale of MPB because these patterns represent the majority of how men lose their hair. When designing a pattern for hair transplantation, it is imperative that the physician follows the rules prescribed by the N-H scale so that the result will mimic nature.
The primary goal in most first cases of hair transplantation is to “frame the face”; that is, to provide hair along the frontal region of the scalp so that the person has a more attractive face when hair is there to frame the face. Many men who are thinning throughout may become focused on their crown, which is an important area for transplantation. Nevertheless, the surgeon in most cases should steer a man toward the importance of framing the front of his scalp first, so that there is a frontal aesthetic benefit. This observation brings up an important corollary point, namely that there typically is not enough hair to transplant both the front of the scalp and the crown in a single session of hair restoration when performing a standard linear harvest from the back of the head. Typically a minimum of 1 year should pass before performing a second donor harvest to ensure that the donor scar is sufficiently healed and relaxed, and also so that most of the hair-transplant result can be observed growing in, thus to determine if a few extra grafts would be beneficial in the previously transplanted zone.
Procedural approach
Hairline Design
Hairline design is very important because it represents one of the most tell-tale signs of the artistry and judgment of a surgeon, and will be the most conspicuous and lasting testament to his work. A hairline must not only look natural for today’s patients; but with predictive capacity accumulated from experience, a surgeon must also ensure that the hairline will not become incongruous for an individual as he further ages. The lowest acceptable, midline point for the hairline is drawn first with a colored eyebrow pencil and typically represents the 45° intersection of the vertical plane of the scalp (the forehead), and the horizontal plane of the scalp (the hair-bearing scalp) ( Fig. 1 ). It must be emphasized that this is the lowest point, but the physician may decide to be more conservative with the design and start higher up. However, if the starting point is too high the physician may fail to frame the face properly. The surgeon then should draw the lateral termini of the hairline where, at a point lateral to this terminus, the temporal hair begins. The lateral terminus of the hairline is situated at a vertical line drawn upward through the lateral canthus of the eye. After drawing this lateral point, the surgeon tilts the head downward to ensure that both lateral points are situated symmetrically both in the anterior-posterior direction and laterally from the midline. The surgeon then should gently connect these dots using a rounded arc with the option to suppress the arc more concave lateral to the midpupillary line, based on the patient’s head shape and other artistic criteria. Once these points are connected, the physician should walk to the side of the patient and ensure that the hairline is either flat along the Frankfort horizontal plane or slopes upward ( Fig. 2 ). If the hairline slopes downward from the lateral view, this is not a natural configuration that exists in nature. Finally, the physician should close one eye and use a mirror to evaluate the hairline so that the hairline is observed in a 2-dimensional, flat aspect. Doing so provides rapid feedback as to whether the hairline is reasonably straight, although it may look tilted even though it looks straight 3-dimensionally with both eyes open. The reason for this discrepancy is that the asymmetric topography of bony scalp can throw off the shape of the hairline more on one side than the other. Accordingly, it is important for the physician to marry the best 2-dimensional and 3-dimensional evaluations of a planned hairline. Once the hairline has been confirmed by the patient and the surgeon to be appropriate, the surgeon can then reinforce the initial tentative eyebrow marking with a more tenacious Sharpie permanent marker, but slightly irregularizing the line when drawing it in to ensure that the hairline will be more irregular (ie, natural) than a straight line.
Donor Planning
Once the area of baldness has been outlined, the surgeon should now plan how many hair grafts will be needed to fill the proposed circumscribed region. One can accomplish this task by first determining how many follicular units (FU) exist per cm 2 in the donor area. For example, if there is observed to be on average 100 FU/cm 2 the donor area and there are 100 cm 2 of area to be transplanted in the recipient area with the desire for approximately 25 FU transplanted per cm 2 in the recipient area, then one will need 25 FU/cm 2 × 100 cm 2 = 2500 FU. If the donor density again is 100 FU/cm 2 , one will need to harvest an area of approximately 25 cm long × 1 cm wide to attain the requisite number of grafts to cover the proposed area for transplantation. There will undoubtedly be some transection of hairs during harvesting, so the surgeon should factor 5% to 10% loss when planning the donor area.
The so-called safe donor area is roughly situated around the occipital protuberance in the midline occiput and arches upward to approximately 2 fingerbreadths above the superior helix of the ear ( Fig. 3 ). This area is then shaved with a short guard (leaving approximately 1 to 2 mm of hair left) for 2 to 3 cm around the proposed area of harvesting, with the long hair above the incision taped upward to keep it out of the way for donor harvesting. Of note, the patient is sitting upright for the entire period of hairline design, donor planning, and donor harvesting.
