Nordstrom and, later, Marritt described the use of micrografts (1 or 2 hair grafts) for the frontal hairline to camouflage scars from plugs or previous hair transplantations and to provide a transition zone and a natural-looking front hairline. However, the use of such small grafts was time-consuming and, at the time, appeared impractical for treating large areas of baldness.

The use of micrografts and minigrafts (3 or 4 hair grafts) in combinations of more than 1000 grafts per session (megasessions) to cover the entire area of baldness was originally described in the mid-1980s by Uebel. Headington studied the transverse microscopy of the scalp and found that hair grows in follicular units — that is, in groups of 1, 2, 3, or 4 hairs, with each group containing an independent neurovascular bundle, sebaceous glands, sweat glands, and piloerectile muscle, all surrounded by a fine circumferential sheath of collagen. These units appear, to some degree, to be true physiologic entities, so that maintaining them as intact as possible improves hair survival and ultimate hair growth ( Figure 1). Skeletonizing the grafts to the bare hair shaft jeopardizes their survival.

I have described further refinements in surgical technique, in particular the use of 2000 to 2500 micrografts and minigrafts in a single session to make more progress in fewer sessions while providing entirely natural hair lines. The maximum number of grafts I have performed in a single session is 2785. Strict attention to detail is important in obtaining an aesthetically pleasing result, including accurate and atraumatic dissection of the occipital donor strip into the individual micrografts and minigrafts and gentle graft insertion. The design of the hairline — its level and distance from the eyebrows — and creation of a slightly asymmetic contour to mimic nature are also important.

Methods

Indications and contraindications

To be a candidate for this procedure, a patient had to have a favorable ratio of donor hair supply (from the occipital and posterior temporal areas) with respect to the surface area requiring hair restoration. Ideally, he or she was a mature adult, 40 years or older, because at this age the patient’s hair-loss pattern is well established. However, we have also treated younger patients conservatively, as long as they understood that they would continue to lose hair and more than likely would require additional transplantation procedures. Although the transplanted hair generally is quite durable, the primary or native hair of the patterned area of hair loss will tend to continue shedding.

During the initial consultations, candidates were told that 1 session would give them significant improvement but that a second session is often required to achieve optimal results with regard to hair density. Factors such as thickness (hair mass), color, and texture also affect the final result, especially with respect to the appearance of hair density (fullness).

Individuals with a very limited donor area and large areas of baldness were not candidates for this procedure.

Patients

Between March 1994 and March 2002, 453 consecutive patients, comprising 399 men and 54 women, underwent hair transplantation, performed in accordance with the technique described below. Patients ranged in age from 21 to 72 years (mean 42). Follow-up ranged from 6 months to 8 years.
Technique

The final aesthetic result depends on hairline shape and level, irregularity and some degree of asymmetry in contour, direction of hair growth, and absence of detectable scarring. Because patients have different head sizes and craniofacial proportions, no set formula exists with which to determine the ideal distance between the eyebrows and the anterior hairline. An aesthetic approach must take such differences into account in determining the appropriate hairline level, which ranges between 7 and 10 cm.

The patient was placed in the supine position, under intravenous sedation with midazolam and fentanyl, and occipital and supraorbital nerve blocks with 0.5 % bupivacaine with epinephrine 1:200,000. A horizontal ellipse of scalp was harvested from the occipital area; this sometimes included part of the posterior temporal scalp (Figure 2). The dimensions of the ellipse varied, depending on the number of grafts planned and the density of the donor site. When 2000 or more grafts were planned, the ellipse generally measured 23 to 26 × 2 cm in width at the midline, tapered to 1.5 cm as it approached about 3 to 5 cm laterally, and, beyond that, tapered to 1 cm as it proceeded further laterally. Scalp tightness was greater laterally than at the midline, and it was important to keep this in mind during closure to avoid undue tension.

With the patient’s head turned to the left, I harvested the right half of the ellipse and immediately dissected it under 3.5× loupe magnification into 2-mm-thick slices (Figure 3). These slices were then dissected into individual follicular units (micrografts or minigrafts) by 2 or 3 surgical technicians, usually also under 3.5× loupe magnification ( Figure 4). Sometimes a 10× microscope was used, especially if the hair was gray or very light in color, because this made the dissection easier and safer. As the grafts were dissected, I closed the right side of the ellipse by performing a single-layer closure with 3-0 Prolene, (Ethicon, Inc., Somerville, NJ) or nylon. Once closure was complete, the patient’s head was turned to the right and the procedure was repeated. Conservative undermining was performed as needed, although the donor site was not infrequently closed without the need for undermining.

I inserted the grafts with the use of a “slit-and-slide” technique, in which the slit was made with a 22.5 Sharpoint blade (Surgical Specialties Corp, Reading, PA) (Figure 5) and an assistant immediately inserted the graft by sliding it along the side of the blade. To keep grafts from “popping out,” they were initially inserted 5 mm apart. After 20 to 30 minutes, when the fibrinogen had converted to fibrin and the grafts were a bit more stable, I made slits about 2.5 mm apart, again working anteriorly to posteriorly. This process was repeated until all the grafts were inserted and densely packed, 1 to 1.5 mm apart. Greater emphasis was placed on the anterior scalp rather than the posterior because the anterior is more important in framing the face and the hair can always be combed back to help cover the posterior scalp.