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Analysis of the unfavorable result in hair transplantation can be analyzed as either an error in judgment or an error in technique. One of the most common errors in judgment is ignoring the fact that hair loss is progressive. Other errors in this category include transplantation at too early an age or ignoring the normal contour of the frontotemporal angle. The other major category involved in the unfavorable result is that of an error in technique. Historically, the unsightly plug grafts used in past were the greatest source of problems. Even with today’s technique using small natural appearing grafts of one to three hairs, errors in technique can create an unnatural result. These include improper angulation of the grafts, poor graft preparation, poor donor site closure, and poor design of the transplanted hairline. The key component of a successful hair transplant is creating a natural appearance, and thorough knowledge of the components of a natural hairline is critical for a successful outcome. However, once an unfavorable result does occur, a logical approach to revisionary surgery is important as options are often limited. This discussion will present specific options that are available to these patients in an attempt to improve their results.
Probably no other area of aesthetic surgery has produced so many bad results as hair restoration. So the question obviously is, What is the source of an unfavorable result in hair transplantation? An analysis of the unfavorable result falls into two major areas, either errors in judgment or errors in technique. To analyze the variables leading to an unfavorable result, it is important to identify the components of a natural hairline and associated natural-appearing grafts. It is ironic that the good results in hair transplantation should, by definition, not be noticeable and the poor results are very visible.
Errors in judgment can be divided into three categories. The first is ignoring the fact that hair loss is progressive (Fig. 1). The second consists of a poor design of the hairline, either placing it too low, making it too straight, or ignoring the frontal temporal angle (Fig. 2). The third major error in judgment is performing the procedure at too young an age (Fig. 3). Probably the most significant of these three categories is the first, that hair loss is progressive.
The other major topic after errors in judgment concerns errors in technique. This topic can be divided into four major categories. The first is previous plug grafting, which should not be performed in today’s patients (Fig. 2). The second is improper angulation of the grafts, which is due to improper placement at the time of the procedure (Fig. 4). The third is improper graft preparation with poor graft take or yields. The fourth is donor site and recipient site problems. For example, using multiple donor site levels creates significant scarring or poor closure of the donor site defect.
Before proceeding with the discussion on the unfavorable result, it is necessary to quantify the components of a good result for an objective comparison.
Five components of a natural hair restoration will be described. These components include creating an irregular, feathered anterior hairline by placing small grafts along the frontal margin, which produces a feathered transition zone. The second component consists of an age-appropriate hairline (Fig. 5). An age-appropriate hairline for most individuals should be at least 8 to 10 cm above the glabella. What may look good on an 18-year-old rarely looks natural on a 50-year-old individual. Therefore, even if one plans to transplant a person in their 20s, it is critical to create a hairline that will look age appropriate in their 30s or 40s. As a rule of thumb, high hairlines rarely look unnatural, and low hairlines can be a major problem. Creating a normal frontal temporal angle is the third component (Fig. 6). Rounding off at a frontal temporal angle will lead to an unnatural appearance. Adult hairlines usually include an acute frontal temporal angle, which becomes more prominent as the individual ages. Also, rounding off of this angle in hair transplants can lead to a bizarre appearance, as the original hairline recedes, leaving an isolated tuft of transplanted hair in the temporal area, surrounded by a non–hair-bearing bald zone. Irregularity and asymmetry are the fourth components. Symmetry is often a goal in aesthetic surgery with exact attention to detail to avoid irregularity or unevenness. In hair transplantation, however, irregularity with some asymmetry is a critical component in creating a natural restoration. A perfectly straight hairline even with small natural grafts will look artificial (Fig. 7).
The fifth and final component of a natural hair restoration is the use of natural-appearing grafts, including, micrografts and follicular units.1,2,3 These five components; a feathered hairline, age-appropriate hairline, natural frontal temporal angle, creation of irregularity, and natural-appearing grafts, are all critical to create a hair restoration that appears natural.
The patient population seen for hair transplantation revision can be divided into three groups. These include patients with old unsightly plugs, patients who had appropriate micrografting but because of poor design or progressive hair loss now have secondary problems, and patients who have had previous cosmetic surgery such as facelifts or forehead lifts with secondary hair loss. Many patients from the late 1950s to the late 1980s had primarily hair restoration with unnatural appearing plug grafts, often containing 10 or more hairs per graft, leading to the typical corn row or doll’s hair appearance (Fig. 8). This group also has a significant deformity at the donor site because of the technique by which the grafts were harvested.
The second group of patients seen today for revisions may have had the procedure done with small or more natural grafts but one of the errors in judgment or technique, which have already been described, were violated. These errors include too straight a hairline, too low a hairline, or a procedure that was performed at too young of an age, resulting in an unsatisfactory result. Either of these groups requires a careful analysis prior to any corrective procedures. These patients often have significant scarring and limited available donor hair, making any corrective procedure a challenge. The plug technique employed for over three decades used a corning device to obtain the donor grafts and the resulting donor defects were allowed to heal by secondary intention, leading to significant scarring. Many of these patients have very little donor hair left. However, when adequate donor hair is available, a combination of further grafting with small natural one- to three-hair units, combined with plug excision, recutting, and recycling, can often give a significant improvement for these patients. Also, in selective cases, the scarring of the donor site can be improved by excision of the scarred areas. Another problem associated with large plug grafts is the phenomena of cobblestoning, in which an area of skin associated with the plug grafts often appears somewhat raised, even if hair successfully grew within these plug grafts. The plug graft skin develops a circular trapped door appearance due to circumferential scarring with elevation of grafts resembling cobblestones. In those patients where the hair did not grow, this cobblestoning phenomena is even more apparent. Adjunctive procedures in this group of patients with unsatisfactory results from previous plug grafts can include scalp excisions and forehead advancement as part of the plug removal process. These more aggressive procedures will be discussed under specific cases.
Another factor to be considered in hair restoration is poor growth of the transplanted hair. Even under the best circumstances, there is an occasional patient where the transplanted hair fails to grow at times for unknown reasons. When large plugs were previously used with 20 to 40 hairs per plug, frequently, the follicles along the periphery of the graft would become adequately revascularized and this hair would grow. However, a central ischemic area often would be present with hair failing to grow within this central core. The larger the plug grafts, the more likely this phenomena would occur. With today’s small grafts frequently containing one to three hairs, the tissue usually revascularizes successfully with excellent hair survival. However, if the grafts are prepared by inexperienced individuals and not meticulously created, the success rate can fall off.
The third group of patients seeking revision or secondary work for hair loss are the post–cosmetic surgery patients.4,5 This group includes patients after facelifts and forehead lifts who have had secondary hair loss in the temporal, frontal, preauricular, and postauricular areas (Figs. 9A and and9B).9B). After a facelift or forehead lift, there is a component of ischemia to the surrounding tissues and the hair follicles may go into telogen. Usually, waiting 6 to 9 months will allow the hair to regrow in many of these patients. However, if there was excessive tension at the time of the incision, closure, or superficial undermining of the skin flaps with damage of the hair follicles, the hair may not regrow, and hair transplantation may be required. Also, traumatic alopecia due to bulb ischemia can be seen when a patient is comatose and lies in one area for a prolong period of time. This relative ischemia may not necessarily lead to skin necrosis but only to hair loss, since the skin is far more tolerant of ischemia than the hair bulbs.
Avoiding creating an unfavorable result in the first place, obviously, would be a desirable option. The purpose of discussing the relative contraindications is to reinforce the fact that hair loss is unpredictable and many patients with unfavorable results could have been spared these problems if these guidelines were followed. Problems are therefore more likely to surface when any or all of the following occur1: performing hair transplants at too young an age2; creating a juvenile hairline3; operating on patients with extensive hair loss with minimal donor hair4; overgrafting the occipital area.
These relative contraindications are important to understand to reduce the risk of creating an unsatisfactory or unfavorable result. Although this discussion is limited to the revision of the unfavorable result, it is important to discuss the relative contraindications of hair restoration. Hair loss is not only progressive but it is also unpredictable. Unlike aging of the face, which has many predictable components, hair loss can be very unpredictable. Taking into consideration family hair loss patterns may be useful but only as rough guidelines. One of the most commonly heard statement by patients who began hair transplantation in their late teens or early 20s is, “I wish I had waited.” Filling in minimal anterior recession in a young patient who is destined to have major hair loss, even with excellent modern techniques, can lead to a very unhappy patient at a later date. The reason is due to an error of judgment, not necessarily related to an error in technique. Frequently, young patients will wish to create a juvenile rounded hairline filling in the temporal recession. It is important to explain to these young patients the long-term problems that will occur if these approaches are taken. The doctor should not be talked into a hairline against his or her better judgment. Another group to consider in the relative contraindications category is the patient with such extensive hair loss that very little donor hair is available. These patients, if they do have hair transplantation must consider objectively the limitations; otherwise, they will be disappointed with the result. Finally, the occipital area must be evaluated with great care. Overtransplantation of the occipital area, especially in a young patient, can lead to a very bizarre appearance as the patient ages. The transplanted hair in the occipital area remains while a zone of baldness develops circumferentially around this area, creating an isolated tuft of occipital hair with a surrounding bald halo. In summary, evaluating a patient based on age, family history, patterns of hair loss, and amount of donor hair, as well as their current hair pattern, helps in reducing long-term problems. Avoiding creation of the unfavorable result in the first place, obviously, would be the ideal situation; however, this discussion is focused on correcting those problems that have already occurred.
What are the factors separating the natural from the unnatural hair restoration? To correct the unfavorable result, a complete understanding of the normal anatomy and characteristics of the natural appearing hair pattern must be understood. This discussion includes two topics, relevant anatomy of individual hairs and relevant anatomy of the normal hairline.
The individual characteristics of the patient’s hair and skin are critical factors. The less contrast in color between the patient’s skin and hair, the more natural the result will appear after transplantation; the greater the contrast between skin and hair color, the more obvious or unnatural the potential result may be. Therefore, light hair and light skin color or dark hair and dark skin color are two examples of low-contrast situations. These two examples result in hair that does not stand out from the underlying scalp. These low-contrast situations appear to give greater coverage of the scalp. The converse is that dark hair and light skin or light hair and dark skin can be more difficult to give a natural result and appear to give less coverage of the scalp. These high-contrast situations are even more obvious if large grafts of more than two or three hairs per graft are used.
Other anatomic components of hair important for this topic of revisionary surgery include hair texture, density, and curliness versus straightness of the hair. Curly hair gives better scalp coverage than straight. Therefore, fewer grafts with curly hair can give a successful result, while straight transplanted hair may require more grafts. Thick hair also gives better coverage than fine hair; however, color contrast, as already discussed, may over ride these other variables.
Part of the anatomy of hair that also must be discussed pertains to the direction of the individual hairs as they exit the scalp. Depending on the location of the scalp, hair grows at different angles and proper angulation is critical for a natural result. Even small grafts will appear unnatural if placed at the wrong angle. Hair along the frontal hairline has an anterior angulation. The reason why many previously used pedicle flaps for hair restoration gave an unnatural result was because the hair grew posteriorly at the frontal hairline with these procedures.6,7 This is in the wrong direction. Also, pedicle flaps used to create a frontal hairline create a very straight and unnatural appearance (Fig. 10). Hair in the temporal area needs to be angled downward, as does hair in the posterior scalp, while hair on the top of the head tends to grow straight up.
The second topic related to anatomy is the hairline itself. This part of the procedure is well within the control of the surgeon, unlike the characteristics of the patient’s hair, which are outside the doctor’s control. What makes a natural hairline versus an unnatural hairline? First of all, the hairline must be at least 8 to 10 cm above the glabella, if not higher. Second is the importance of maintaining the frontal temporal angle. Most mature males have some component of temporal recession, which increases naturally as they age. Therefore, the hair restoration must include this temporal recession. Those patients in which a juvenile hairline was created will often need a procedure to recreate the temporal recession. They frequently require excision of the previous grafts and possible scalp excision with forehead lifting. Irregularity and feathering are also critical components of natural restorations (Fig. 11). A perfectly straight hairline even with small grafts will appear unnatural. Also, the hairs along the frontal fringe should be small, fine single hairs to help create a normal feathering margin.
Once we understand the normal versus the abnormal anatomy, the next step to correct the problem is to accurately define those components that have created the specific unfavorable result. This topic can be divided into five groups. The corrective procedures can include any one or a combination of these procedures. The first is correction of cornrow plugs, which can include excision alone, with no further grafting, or excision with regrafting. The second is correction of the isolated frontal forelock, which may result as the patient who has had previous frontal grafting ages (Fig. 12). The third is correction of a temporal alley, which can also occur because of progression of hair loss after transplantation (Fig. 13). The fourth is correction of an abnormally transplanted hairline, including one that was made too straight, too low, or with improper angulation of the grafts. The fifth is correction of posttraumatic hair loss.
Frequently, revision of the unfavorable result cannot be corrected by any single procedure but will require a combination of surgical technique.8,9 The preoperative assessment of a patient who has had previous hair transplantation is very different from the patient who has not had one. The difference between these two groups are even more magnified when comparing the patient who has had a successful procedure in the past and only wishes more grafting as compared with the patient with an unsuccessful result, due to either poor hairline design or large plug grafts. The evaluation includes not only the recipient site but also the donor site. A frequently seen problem is extensive scarring in the donor area due to plug graft donor site healing by secondary intention. Also seen are patients in whom multiple-level linear excisions have been taken in the posterior scalp donor site, leading to multiple parallel stair-step scars. This specific problem can be reduced by taking the donor site at the same location with each additional procedure.
In some cases, simple excision of the plugs with no further grafting can improve an unnatural result, especially if the number of plug grafts are limited (Fig. 14). Also, in patients with little or no donor hair left, this may be the only option. Patients with old plugs may have sites or areas within the plugs with poor or even no hair growth. This occurs because the skin of the plug graft was neovascularized and survived, but the follicles within never successfully grew hair. This is a very unsightly look and excision of the non–hair-bearing skin plugs is frequently the best solution. In other plug graft patients where adequate donor hair still remains, two procedures are available. First, the most obvious plug grafts can be excised, recut into small micrografts, and replanted. Second, additional donor hair, if it is available, can be harvested from the posterior scalp and additional small micrografts inserted between the previous plug grafts, creating greater density to mask any remaining plugs. In more extensive cases where the number of plug grafts are too great for isolated individual plug excision, a radical excision of the scalp including the unsightly plugs may be the best option (Fig. 15).
Direct excision of old plugs can be performed with a no. 11 blade using magnification. Magnification is important as the specimen needs to include the follicles to prevent regrowth of the unsightly plug. If the plugs are to be recut into smaller grafts for replantation, care must be taken to avoid injury to the follicles. Because of previous scarring associated with plug grafts, only about a half of those reharvested yield specimens that are good for reinsertion. However, because these patients have limited donor hair, every one of these hairs counts.
One of the most difficult groups of patients to correct are those where the hairline was originally placed too low, especially with unsightly plugs. The old plugs must be carefully excised and recut into small grafts. Many of these patients, however, will also require a scalp excision, associated with a forehead lift.10 In these complex cases, the entire surgical armamentarium of corrective options may be required (Fig. 16).
The first step is excision of the frontal hairline scalp as an ellipse incorporating the old unsightly plugs. The old plug grafts removed with this anterior ellipse of skin are used to create new small (one- to two-hair) grafts.11 While the excised hair is being recut, a forehead lift is performed. In this situation, the goal is mobilization and advancement of the forehead not elevation of the eyebrows. The forehead skin is advanced superiorly to raise the new future hairline. The dissection does not go below the superior orbital ridges. The frontal forehead is stretched superiorly by making numerous parallel, horizontal releases in the periosteum in a subperiosteal dissection or in the galea in a subcutaneous dissection. Deep sutures of 3–0 Ethibond are used with either Mitek fixation devices or outer table drill holes to fix the forehead in an elevated position. The boney fixation is placed several centimeters above the new future hairline to allow maximal elevation.
Once the forehead has been adequately elevated along its superior aspect, the skin is closed with 3–0 Vicryl and running 3–0 or 4–0 Monocryl. The old plugs, which have been recut into small grafts, are now reinserted. Once the skin excision site has healed (in 3 to 4 months), further grafting is performed to create a new and natural hairline.
Another challenging group is the patients with extremely straight hairlines. It was common for hair transplant patients in the past to have extremely straight and unnatural-appearing hairlines. Hairlines need to be irregular and even in those patients with small grafts, straight hairlines are unnatural. If the straight hairline includes unsightly plugs, these need to be removed, as previously described, and recycled. Many of these patients can be improved as long as the hairline is not too low by placing small (one- to two-hair) grafts in an irregular pattern in front of the previously grafted areas.
In patients with light skin and light-colored hair, it is easier to accomplish an improvement, compared with patients with dark hair and light skin. As previously discussed, the closer the hair and skin color are to each other, the easier it is to correct a straight hairline, and the greater the contrast, the harder it is to correct the straight hairline. In high-contrast patients (for example, dark hair and light skin or light hair and dark skin), a greater number of grafts will be required to mask the previous surgery and create irregularity. This is true for all corrective procedures and color contrast, as already discussed, is a subtle but important issue when doing secondary hair restorations.
In a patient with improper angulation of previous grafts, simply filling in between with new grafts will not solve the problem. These grafts must be excised carefully, as previously discussed, with regrafting of the entire area, using both the old recut grafts with new ones.
Patients with traumatic hair loss (frequently after cosmetic surgery) are the final group presented. The group primarily consists of patients after a facelift or browlift. In some, simple excision of the non–hair-bearing scar can be successful. However, this maneuver often fails because the new scar site continues to lose its hair. Re-excision, because of the risk of undue tension, leads to ischemia and further hair loss.
For these reasons, many patients with traumatic hair loss require hair transplants (Fig. 17). It is interesting that small hair transplants placed directly into scar tissue usually grow. The major problem with placing small grafts into scar tissue is mechanical. Unlike normal scalp, which is fairly thick, areas of hair loss with or without scar tissue are frequently thin and it can be difficult to insert the grafts in these areas. Tumescing the recipient areas can facilitate placement of these grafts in scar by increasing the thickness of the recipient tissue for graft insertion. In some of these patients, the grafts cannot be placed as close together because of the thin scar, which is relatively ischemic. In these patients, several sessions spread out over time may be more appropriate. Most patients with traumatic hair loss, however, can be repaired in two sessions of grafting. Another approach consists of combining excision with grafting. Excision of a portion of the non–hair-bearing area results in a smaller area needing grafting. When combining these two procedures, it is important to be conservative with the amount of skin excised as further tension with ischemia will lead to more hair loss. One of the benefits of today’s small micro- or follicular grafts is the high success rate of the grafts. These smaller grafts have less metabolic demands than the old larger grafts and usually do well in scar tissue and even in skin grafts.
In summary, successful salvage of the unfavorable hair transplant patient requires careful analysis of the mechanism of failure. There are several procedures that can be used in these complex cases, which are determined by the source of the original problem. Most patients with unsatisfactory results have very similar histories. These include grafting at too young an age, the use of unsightly hair plugs, and placing the hairline too low or too straight. The most important concept to remember is that hair loss is “progressive.”