The Art of Integrating Follicular Units and Follicular Groupings in Hair Restoration Surgery.

HAIR RESTORATION surgery has gone through a vast array of vacillating changes over the past 50 years. Originally, in 1939, a Japanese dermatologist named Okuda¹ introduced the use of small full-thickness auto grafts of hair-bearing skin for the restoration of the scalp, eyebrow, and mustache areas. In 1943, Tamura² published an article on the use of single hairs to reconstruct the female pubic area. Subsequently, Fujita³ used a similar technique to treat scars, eyebrows, eyelash defects, pubic areas, and alopecia areata. But because these original articles were published in the Japanese literature and World War II was under way, they went unnoticed by the rest of the world.

In the early 1950s, Orentreich⁴, with no previous knowledge of the Japanese experience, began experimenting with the concept of donor and recipient dominance. He took biopsies of normal skin and diseased skin and transplanted these into other areas of the body to evaluate whether or not the biopsied skin would maintain its characteristics or would change in accordance to the area it was grafted into. He also took biopsies of scalp on the sides of the head of balding men and transplanted these into balding areas. What he found was that the scalp from the occipital and parietal areas would grow and thrive in an area where hair was no longer growing. Thus, the theory of donor dominance was conceived—the donor hair would dominant in an area of pattern baldness. It was this revelation that catapulted the field of hair restoration surgery in the United States.

During his initial experience, Orentreich would create the grafts with 6.0- to 12-mm trochars and would perform six-punch grafts (Berger R, personal communication, July 1995) at a time. But as the years went on it was not unusual for he and other practitioners^5–7 to perform one-hundred 4.0-mm punch hair grafts per session. This technique resulted in an average of 20 to 30 hairs per graft, but the results were usually cosmetically unpleasing because of the fact that the 4.0-mm plug had no counterpart in nature.

Hair restoration surgery made a major leap in 1981 when Nordstrom and colleagues⁸ introduced the idea of utilizing three- to six-haired grafts at the anterior edge of the hairline. Later, in 1984, two major events occurred that would change the face of the field forever—Bradshaw⁹ introduced the idea of utilizing smaller six- to eight-haired quarter grafts over the entire head to achieve more refined cosmeses and Headington¹⁰ clarified the follicular unit. In Headington's article the medical community learned that a follicular unit included:

This definition helped us understand that the follicular unit was not only an anatomic unit, but was more importantly a physiologic one. This understanding subsequently ushered in the philosophy that the follicular unit should be left intact and not be broken apart. In 1987, Limmer¹¹ was the first to use Headington's information clinically by utilizing the stereoscopic microscope to create follicular units, which would later be used for surgical hair restoration. Later in 1996, Seager¹² gave significant credence to the philosophy of keeping the follicular unit intact when he demonstrated that when single-hair micro grafts were created from follicular units, their growth was not as good as intact follicular units. In his study, he demonstrated that at 5½ months the one-haired micro grafts had an 82% survival rate, compared to the 113% survival rate of intact follicular units. This 113% rate was most likely due to the sudden growth of anagen effluvium hairs added to the new growth from follicular units.

Since 1996, the exclusive use of follicular units has gained in popularity primarily owing to the writings and lectures of Rassman and Bernstein^13,14 and others. Although results with the exclusive use of follicular units is physiologically sound and aesthetically pleasing, it does have the downfall of taking an inordinately long time (6–8 hr) to complete a session and being more costly to the patient. There also can be some follicular damage when two follicular units are extremely close together. These two negatives are especially evident when the cosmetic surgeon performs follicular unit transplantation infrequently, because the staff does not have the adeptness to move quickly. Although some centers report transection rates of 0% to 3%, these are among the very elite facilities and do not represent the average hair restoration surgeon. This article demonstrates a technique that leaves the follicular unit intact, but allows for the use of three and four-haired follicular groupings when follicular units are very close together. This combination allows for a quicker procedure and less iatrogenic damage of follicles, both of which should give better hair growth, and is less costly to the patient.

Graft Creation Technique

A 1.0 x 20.0-cm fusiform strip is normally excised from the donor site and is immediately handed to the surgical assistants who begin slivering the strip into very fine strips that are one follicular unit in width with the help of a stereoscopic microscope (Figure 1). A multiblade strip technique is not utilized because of the known increase in iatrogenic damage to the follicles during extraction. Once the very thin slivers from the fusiform strip are completed, the assistants then dissect these into six different types of grafts:

A one-haired follicular unit is obviously a single hair egressing the scalp alone (Figure 2). A two-haired follicular unit is a bundle of two hairs egressing the scalp through one opening (Figure 3). A three-haired follicular unit is similarly a bundle of three hairs egressing the scalp through one opening (Figure 4). A four-haired follicular unit is a bundle of four hairs egressing the scalp through one opening (Figure 5).

Although Bernstein¹⁵ has written that the average patient as one follicular unit per square millimeter, these follicular units are not as equally distributed as one might think. There are many times when two follicular units are much closer together than surrounding follicular units (Figure 6). In these cases, the author diverges from the follicular purist and makes a follicular grouping instead of two follicular units. A three-haired follicular grouping is made when a two-haired follicular unit and a one-haired follicular unit are so close together that the assistant feels that there will be a high probability of iatrogenic injury if the two follicular units were dissected apart. In this case, the assistant incorporates the two follicular units, which will make a follicular grouping that will obviously have more tissue (Figure 7). This follicular grouping will therefore require a larger incision at the time of preparation of the recipient sites. A four-haired follicular grouping is formed when either a two-haired follicular unit and another two-haired follicular unit are extremely close together (Figure 8) or a three-haired follicular unit and a one-haired follicular unit are juxtaposed (Figure 9).

Figure 1. A 1.0 x 20-cm fusiform strip is normally excised from the donor site and is immediately handed to the surgical assistants who begin slivering the strip into very fine strips that are one follicular unit in width.

Figure 2. A one-haired follicular unit is a single hair egressing the scalp alone.

Figure 3. A two-haired follicular unit is a bundle of two hairs egressing the scalp through a single opening.

Figure 4. A three-haired follicular unit is a bundle of three hairs egressing the scalp through a single opening.

Figure 5. A four-haired follicular unit is a bundle of four hairs egressing the scalp through a single opening.

Another type of hair graft that has not been written about much in the medical literature but has been observed frequently at the author's clinic is a three or four-haired bundle that appears to be a follicular unit at the surface, but has hair shafts that bow away from the center as the hair enters deeper toward the matrix (Figure 10). Because these grafts require preservation of a fair amount of tissue, which requires a larger incision, we classify these as follicular groupings.

Incisional Technique

The author uses three different spear blades for all six different grafts. A 2.0-mm Swann Morton No. 91 is usually used for all three- and four-haired folliculargroupings. A 1.5-mm Swann Morton No. 90 is typically utilized for all two-, three-, and four-haired follicular units and an Ellis 1.0-mm spear blade is normally used for all one-haired follicular units. Although these blades are usually used in the aforementioned fashion, the author will perform test incisions for each of the grafts so that a perfect snug fit ensues.

Figure 6. Photograph demonstrating that there are times when two follicular units are much closer together than the surrounding follicular units.

Figure 7. A three-haired follicular unit is created when a two-haired follicular unit and a one-haired follicular unit are so close together that there is a high probability of iatrogenic injury if the two follicular units are dissected apart.

Figure 8. A four-haired follicular grouping can be created when two, two-haired follicular units are extremely close together.

Figure 9. A four-haired follicular grouping can also be created when a three-haired follicular unit and one-haired follicular unit are extremely close together.

The advantage of using only a 1.5-mm Swann Morton No. 90 for two-, three-, and four-haired follicular units (instead of a different blade for each) is that the final decision as to where the follicular units will be placed can be slightly altered after all the incisions are completed. This is important because sometimes the prediction as to the breakdown of the various follicular units will change as the assistants are cutting the grafts. Typically, the author knows the exact breakdown of the various grafts when the staff is one-half way through dissecting the fusiform strip, but this does not always occur.

When using 2.0-mm Swann Morton No. 91 blades for three- and four-haired follicular groupings, the author averages 8 incisions/cm², which yields approximately 30 hairs/cm². Conversely, when Swann Morton No. 90 incisions are made for two-, three-, or four-haired follicular units, the author normally makes approximately 20 incisions/cm². If two-haired follicular units were being placed, these incisions would yield approximately 40 hairs/cm². If three-haired follicular units are being utilized this would calculate out to be 60 hairs/cm² and if four-haired follicular units are being used there would be a yield of approximately 80 hairs per cm². When using a 1.0-mm Ellis blade for one-haired follicular units, the author usually makes approximately 25 incisions/cm², which yields approximately 25 hairs/cm². It is the author's opinion that it is essential that when working in areas where preexisting hair is growing, that 3.5 x expanded-loupe magnification can be utilized while making the incisions so that preexisting hair follicles are not damaged.¹⁶

Figure 10. Occasionally, one will observe three or four hairs exiting the scalp in a bundle, but as the hair shaft enters the deeper scalp, the roots bow away from the center. Because those grafts require a large incision, the author classifies those as follicular groupings.

Case Studies

To demonstrate how the cutting and incisional techniques are incorporated on individual patients, the author presents a series of three case studies. The total number of hairs presented in each donor strip is the net number of hairs derived following follicular unit dissection.

Figure 11. (A) The patient is a 50-year-old man with Type VI baldness from the frontal view, preoperatively. (B) Same patient after 4920 hairs were transplanted in two sessions. (C) Schematic demonstrating the breakdown of the donor strip and the subsequent placement of those hair grafts.

The patient is a 50-year-old Oriental man who presents with Type VI male pattern baldness and fine, straight and black hair (Figure 11A). He desires to part his hair from the left and backward. Upon harvesting a 1.0 x 20.0-cm strip the following characteristics were 2.0 present in the strip:

Figure 11C demonstrates the placement of the aforementioned grafts in the density distributions previously discussed in this article. The following is the breakdown of how the grafts were distributed:

After two sessions utilizing this approach the results are as shown in Figure 11B. One can notice that although only 4920 hairs were utilized in this patient, a good result ensued primarily owing to the fact that the hairs were strategically placed in accordance with the desired hairline. Obviously, if this patient wanted further enhancement of the density another session could be performed.

Figure 12. (A) The patient is a 42-year-old man with Type VI thinning, preoperatively. (B) Same patient after 6215 hairs were transplanted in two sessions. (C) Schematic demonstrating the breakdown of the donor strip and the placement of those hair grafts.

This patient is a 42-year-old white man who has diffuse Type VI thinning, thin, straight, and light brown hair (Figure 12A). He requests thickening of the frontal aspect of his scalp and wants to comb his hair straight back. After harvesting a 1.0 x 20.0 cm fusiform strip the following characteristics were present:

Figure 12C demonstrates the placement of the aforementioned grafts in the density distributions previously discussed in this article. As previously alluded to, it is the author's opinion that it is essential in this type of patient to make the incisions in between the preexisting follicular units with the help of 3.5 x expanded loupes. The following is the breakdown of the how the grafts were distributed:

After two sessions utilizing the above approach the results are shown in Figure 12B. One can notice that even though only 6215 hairs were utilized in this patient a fairly good result has been accomplished because the densely packed follicular units at the anterior aspect creates the illusion that the patient has more hair than he really has.

Figure 13. (A) The patient is a 39-year-old man with Type VI thinning, preoperatively. (B) Same patient after 4621 hairs were transplanted in two sessions. (C) Schematic demonstrating the breakdown of the donor strip and the placement of those hair grafts.

The patient is a 39-year-old white man with Type VI diffuse thinning who has coarse, dark brown, wavy hair (Figure 13A). His goal is to wear his hair straight back. After harvesting a 1.0 x 20.0-cm fusiform strip the following characteristics were present:

Figure 13C demonstrates the placement of the aforementioned grafts in the density distributions previously discussed in this article. The following is a breakdown of how the grafts were distributed:

Figure 13B demonstrates the results after two sessions utilizing the aforementioned techniques. Even though only 4621 hairs were utilized in this case, the results are significant because of the strategic placement of the grafts in congruence to the hairstyle desired.

Discussion

As follicular unit transplantation has evolved over the years, there has also evolved a philosophy that surgeons should use nothing larger than a follicular unit during the hair transplantation process. This philosophy has developed because of the fact that the actual proportion of non-hair-bearing skin in a typical fusiform donor strip is probably on the order of 50%, which in turn causes a fair amount of non-hair-bearing skin to be included into any graft larger than a follicular unit. It has been stated that these larger hair grafts will negatively affect the aesthetics of the surgical hair restoration owing to the fact that a good fit into atrophic balding scalp will be difficult to achieve. This poor fit can cause tufting, dimpling, pigmentary changes; depression; or elevation of the grafts. It has also been stated that because larger incisions are needed for larger grafts there can be significant damage to the microvasculature of the recipient scalp.

The author does, in fact, agree with these basic premises, but disagrees when hair grafts have two or fewer closely juxtaposed follicular units. This article describes a technique that never uses more than four hairs per graft (which is in congruent with nature) and never uses more than two follicular units per follicular grouping. Additionally, the only follicular units that are incorporated into one graft are those that are naturally closer together than the others within the donor strip.

Using the approach discussed in this article accomplishes five goals: (1) it allows the procedure to be performed at a much quicker pace owing to less dissecting and less placing; (2) it lessens iatrogenic injury to follicular units during the dissection phase; (3) it lessens iatrogenic injury during the placement phase because follicular groupings are a little less fragile than a follicular unit because more tissue is present; (4) it allows the grafts to be left out of the body for a shorter period of time which increases survival rates; and (5) it is less costly to the patient. The fact that the procedure time is lessened cannot be overlooked as being unimportant. Limmer¹⁷ demonstrated, in an excellent study, that the longer grafts are left out of the body, the lower the survival rate (Table 1). In his study, there was 95% survival at 2 hr, 90% survival at 4 hr, 86% survival at 6 hr, 88% survival at 8 hr, 79% survival at 24 hr, and 54% survival at 48 hr.

Besides survival rates being affected by increased time, one must also account for the fatigue factor as procedures get longer and longer. As surgical assistants get tired, the dissection will not be as accurate and there will be more iatrogenic damage to the hair grafts. In regard to the argument that larger incisions cause more trauma to the scalp, the author believes that the technique described in this article does not increase trauma in any way. In fact, it can easily be demonstrated that there is actually less trauma when the longer 2.0-mm-long blade incisions are made for three and four-haired follicular groupings. For example, when two-, three-, or four-haired follicular units are utilized, the author usually makes 20 1.5-mm incisions in a square centimeter. Therefore, when the total length of the incisions is cumulated a length of 3.0 cm results (1.5mm x 20=30mm=3 cm). Conversely, when the author uses three- or four-haired follicular groupings, he makes eight incisions of 2.0mm in length in a square centimeter. Thus a total of 16mm or 1.6 cm of incisional length is created in a square centimeter (2.0mm x 8=16mm=1.6 cm).

In this article, 5362 hairs were transplanted in Case 1 during two sessions, 6215 hairs in Case 2 with two sessions, and 4621 hairs in Case 3 with two sessions. With each of these cases, all three still have plenty of hair for further surgical hair restoration. To illustrate this numerically, it is well known that the average head contains 100,000 hairs at peak density, with approximately 25% being at the donor dominant area. Therefore, 25,000 hairs are permanent with one-half of these (12,500) being available for transplanting. In Case 1 we have used approximately 43% of available donor hair; in Case 2 approximately, 50% of the available donor hair; and in Case 3, approximately 37%. Although all three of these patients had hair densities that were less than average, these three examples give approximate illustrations as to how each of these individuals will have adequate donor hair in the future to deal with senile alopecia or future male pattern baldness. This was made possible primarily by the strategic placing of certain hair grafts in vital areas based on the patient's desired hairstyle.

Summary

A philosophy has developed in surgical hair restoration that nothing larger than a follicular unit should be utilized in the hair transplantation process. It is the message of this article that when two follicular units are extremely close together, it is better to make a three- or four-haired follicular grouping instead of trying to divide the two follicular units. By utilizing this approach the surgeon will accomplish five things:

(1) the procedure will be performed more quickly owing to less dissection; (2) there will be less iatrogenic damage to the hair follicles during the dissection phase; (3) there will be less iatrogenic to the hair follicles during the placement phase owing to the fact that follicular groupings are less fragile than follicular units; (4) it allows the hair grafts to be left out of the body for a shorter period of time which increases survival rates; and (5) the procedure will be less costly to the patient.

References

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