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Surgery and Cosmetics

Arthur Tykocinski, MD

Advances in Hair Restoration: Follicular Unit Transplantation With Coronal Technique

Arthur Tykocinski

Tuesday, February 06, 2007

Medicine has advanced continuously, but from time to time, there are real leaps forward that dramatically change diagnostic or therapeutic procedures. This has been happening in hair restoration surgery, which has reached a degree of advancement and complexity without precedent.

The complete restoration of a bald area from 80-100 cm2, with high density and reproducing the natural anatomy, is already possible. And the results are good from the patient's perspective as well as being practically imperceptible from the surgeon's perspective, which shows the maturity of the technique.

Beginning of Hair Restoration

Since Orentreich published his paper on hair transplantation in 1959,1 the interest has been enormous. In his study, scalp biopsies from the balding scalp of the frontal area were exchanged with the preserved scalp from the occipital area. He noticed that while the donor hair would grow after some months in the bald area, the bald skin in the occipital area wouldn't recover its hair. After observing this, he coined the term "donor dominance," and from this concept emerged hair transplant surgery. The initial appearance of "doll hair" was very artificial as a consequence of using a big punch of 5 mm. The size was gradually reduced, reaching a size of 2 mm in diameter and giving rise to the generation of the "minigraft," but the results were still noticeable.

In the 1980s, in an attempt to produce esthetic improvement, the "minigraft" gave way to the "micrograft," containing mostly 2-3 hairs, as a refinement for the hairline. It was a great advance, mostly for blonde, fine or gray hair with a reasonably natural appearance. For thick or dark hair, however, it would still produce a rough appearance.

Follicular Unit Hair Transplantation

This is a new concept that has changed everything. For the first time, hair transplantation offers a really natural appearance.

The advantages:

  1. In 1984, Headington, working with "transverse cuts (horizontal)" of scalp biopsies instead of "longitudinal cuts (vertical)," perceived that hair was composed of a unique structure of two to four hairs, its sebaceous glands, and the erector pilae muscle, wrapped in a type of membrane.2 They were described as "follicular units" (FU).
  2. In 1988, Limmer initiated the use of stereomicroscopes to dissect the follicular units, raising the quality of the grafts and decreasing the tissue waste.3 His results were published in 1994.
  3. Many others contributed to the technical improvement. The Moser Clinic started using small incisions to place the follicular unit grafts, producing greater densities and natural results. Other pioneers, such as Rassman, advocated the exclusive use of follicular unit grafts:4 "Since hair naturally grows as individual FUs, it is logical to conclude that transplanting hair exactly the way it grows would produce the most natural results." Shapiro brings art to hair restoration with his irregular delicate approach for the hairline.5 A landmark was the International Society of Hair Restoration Surgery (ISHRS) international meeting in 1999: After the pioneer session "Doctors and their patients" that showed patient results using different techniques, no one doubted the advantages of the follicular unit transplantation (FUT) compared to others.

Coronal-Oriented Follicular Unit Transplantation (Coronal = Lateral or Transversal)

The technique introduced in 2003 by Hasson and Wong took FUT to a new level,6 offering new orientation to the follicular unit placement. The advantages are hairs in more acute angles and greater densities, allowing "cosmetic densities" in just one session.

Natural hair presents itself individually or in groups of 2-4 strands of hair: These are the "follicular units." In general, 60% of follicular units have 2 hairs, 25% have 3 hairs, and 15% have 1 hair. In hair restoration, the natural distribution is respected, consisting of only 1 hair in the hairline, followed by 2-hair FUs, and 3-hair FUs in the biparietal area for a greater volume of hair.

Follicles of the individual FUs tend to arise from the skin in a side-by-side rather than anteroposterior pattern. This pattern is called coronal, transversal or lateral. In the standard FUT, the FU grafts are placed in an anteroposterior pattern, called sagital or perpendicular. Looking at it this way, the coronal technique reproduces better the scalp anatomy in addition to the following benefits:

  1. Angle control: The natural hair varies from 90° (vertex) to 10° (temporal area). The coronal incision allows for precise control of graft angulation by "pressing" the FU graft between the anterior and posterior walls of the incision. In the sagital technique, instead of moving to the sides, the graft can move in the anteroposterior plane. This means they can move and stay elevated and "perpendicular" to the skin, producing artificial exit angles, which are particularly critical in the hairline and temporal area. Producing more acute angles has also the benefit of increasing coverage, by increasing "optical density," like a blind curtain: The more acute the angle, the more difficult it is to see the scalp, producing a "less balding appearance."
  2. Increased density: The natural density of the scalp is usually 80-100 FUs/cm2. Even with a lower density we can produce a "non-balding appearance." The key point is to produce enough density to "block" the scalp view from an observer. This is usually obtained with 40-60 FUs/cm2, varying according to hair diameter, texture, and color, although 45 FUs/cm2 are usually enough. If we consider that density in an FUT depends on many factors such as graft size, incision size and scalp susceptibility to vascular trauma, the determining factor is the incision size. So, the grafts can be easily trimmed to fit smaller incisions and scalp susceptibility to vascular trauma will be the same for each patient.
  3. Smaller incisions:7 Each linear incision in the skin produces an interruption in the blood flow. The more incisions, the more interruptions. So, there is a limit of incisions allowed per cm2 according to each technique, because each incision produces specific tissue damage. By using smaller incisions we can produce greater densities without increasing vascular trauma, allowing enough blood supply for the grafts. Regular sagital FUT uses the popular Sharpoint 15° blades. Each incision with that blade produces 1.4 to 1.59 mm of linear damage, according to the depth, and allows densities of 20-25 FUs/cm2, producing a total vascular trauma of 35 mm/cm2. Using the custom blades produced with a blade cutter, we can produce incisions as small as 0.6 or 0.7 mm. If we decide to maintain the same amount of vascular trauma (35 mm/cm2), we can now produce densities as great as 50 (35/0.7=50) or even 58 (35/0.6=58) grafts per cm2. These doubled densities allow the patient to obtain "cosmetic densities" in just one session per area. The patient won't need to come back for another session, which is the main advantage of this technique. The practical aspect is that the patient now is able to "fix" his balding "problem" in just one session. For sure, the clinical treatment should continue to avoid the baldness progression.

Figure 1: Follicular unit grafts with 1, 2, 3, and 4 hairs

Follicular unit grafts with 1, 2, 3, and 4 hairs

Figure 2: Follicular unit graft ready to be inserted

Follicular unit graft ready to be inserted

Figure 3: Follicular units in natural hair

Follicular units in natural hair

Figure 4: 12 days after a coronal follicular unit transplantation

12 days after a coronal follicular unit transplantation

Figure 5: Hairline of the same patient

Hairline of the same patient

Figure 6: Tuff area of the same patient

Tuff area of the same patient

Figure 7: Before transplantation of 1,981 follicular units

Before transplantation of 1,981 follicular units

Figure 8: Hairline after transplantation of 1,981 follicular units

Hairline after transplantation of 1,981 follicular units

Figure 9: Detail view after transplantation of 1,981 follicular units

Detail view after transplantation of 1,981 follicular units

Figure 10: Before transplantation of 1,936 follicular units

Before transplantation of 1,936 follicular units

Figure 11: After transplantation of 1,936 follicular units

After transplantation of 1,936 follicular units



  1. Orentreich N. Autografts in alopecias and other selected dermatological conditions. Ann N Y Acad Sci. 1959 Nov;83:463-79.
  2. Headington JT. Transverse microscopic anatomy of the human scalp. A basis for a morphometric approach to disorders of the hair follicle. Arch Dermatol. 1984 Apr(4);120:449-56.
  3. Limmer BL. Elliptical donor stereoscopically assisted micrografting as an approach to further refinement in hair transplantation. J Dermatol Surg Oncol. 1994 Dec(12);20:789-93.
  4. Bernstein RM, Rassman WR. Follicular transplantation: Patient evaluation and surgical planning. Dermatol Surg. 1997 Sep;23(9):771-84.
  5. Shapiro R. Principles and techniques used to create a natural hairline in hair restoration. Facial Plast Surg Clin North Am. 2004 May;12(2):201-17.
  6. Haber RS, Stough DB. Perpendicular angle grafting. In: Procedures in Cosmetic Dermatology Series: Hair Transplantation. Philadelphia, Pa: Elsevier Saunders; 2006:117-125
  7. Tykocinski A. Safe incisions density in the recipient site: estimating it for different instruments. [Oral communication]. ISHRS XII Annual Meeting. 2004. Vancouver, Canada.