By Aman Dua
Hair transplantation has come a long way from the days of Punch Hair Transplant by Dr. Orentreich in 1950s to Follicular Unit Hair Transplant (FUT) of 1990s and the very recent Follicular Unit Extraction (FUE) technique. With the advent of FUE, the dream of ‘no visible scarring’ in the donor area is now looking like a possibility. In FUE, the grafts are extracted as individual follicular units in a two-step or three-step technique whereas the method of implantation remains the same as in the traditional FUT. The addition of latest automated FUE technique seeks to overcome some of the limitations in this relatively new technique and it is now possible to achieve more than a thousand grafts in one day in trained hands. This article reviews the methodology, limitations and advantages of FUE hair transplant.
Modern hair transplantation was introduced in the 1950s by Dr. Orentreich.He started with the help of 4 mm punches. Then the concept of mini and micrografting, and later in 1990s the Follicular Unit Hair Transplantation (FUT)took over. With FUT, transplantation of hair in naturally occurring individual follicular units was established. In these methods, donor harvesting was done by single strip method with elliptical excision of donor, followed by suturing. The significant disadvantage of single strip harvesting was the resultant linear donor scar. Though it is possible to provide a very fine linear scar with the newly described trichophytic closure, it does pose cosmetic problems for many patients particularly those who wish to wear short hair. Bernstein and Rassmanstarted developing the FOX procedure, heralding a new surgical hair restoration procedure without strip harvesting. The FOX procedure, also known as FUE (Follicular Unit Extraction), FUSE (Follicular Unit Separation Extraction) method, Wood’s technique, FU Isolation method is fast becoming an alternative method of extraction of grafts as follicular units in selected cases. While there are many limitations to this new technique, several new developments are taking place to overcome the limitations of number of grafts in one session of FUE.
This article presents a review of different aspects of FUE such as, the prerequisites of doing FUE hair transplant, indications and contraindications, procedure, limitations and the latest advancements in the field of FUE.
In FUE, the extraction of intact follicular unit is dependent on the principle that the area of attachment of arrector muscle to the follicular unit is the tightest zone. Once this is made loose and separated from the surrounding dermis, the inferior segment can be extracted easily. Because the follicular unit is narrowest at the surface, one needs to use small micropunches of size 0.6–0.8 mm and therefore the resulting scar is too small to be recognized
The main anatomical limitation of the technique is that it is not possible to identify the bulge of the hair from outside and hence the procedure is blind. Also, since the hairs with intact unit splay at the lower end and diverge in different directions, the process of extraction can result in a higher transection rate. The procedure is also slow as each unit has to be pulled out slowly. However, with experience, the hand eye coordination and speed of the surgeon, transection rate can be improved.
Following are the prerequisites for doing FUE:
- Adequate experience and training of the surgeon
- Excellent lighting
- Adequate magnification for the surgeon and staff
- Proper understanding of the angle of the hair below the surface of the skin; in almost all instances, the angle of the emergent hair is more acute than the angle of follicle in the dermis. The incision must obviously anticipate this and be oriented in the direction of the follicle rather than the visible hair.
- Punch size of 0.6–1.0 mm in diameter. This size is large enough to encompass the width of the follicular unit, yet small enough to minimise wound size and scarring. Some surgeons have now started using punches of lesser size starting from 0.6 mm.
- Proper motion of the hand: The hand should be perfectly stable while doing short twisting motion of the punch. Bernstein advocates that clockwise rotation (for the right-handed person) generally provides more stability than twisting in the other direction. A back-and-forth motion causes unnecessary transection and is incompatible with successful FUE, as is a 360 degrees rotation of the punch. In some FOX grade 1 cases, direct pressure alone (without any twisting) may be sufficient to extract the grafts.
- Sharp punches/blunt punches: Some surgeons use sharp punch in two-step technique to minimise the amount of twisting needed to cut into the dermis, whereas blunt punches are used in a three-step technique to decrease the follicular transection rate.
- Positive FOX Test
FOX TEST
It is important to note that the tightness with which follicular units are held in dermis varies and hence FUE may not be suitable in all patients. Therefore, before undertaking any patient for FUE hair transplant, the surgeon should ascertain whether the patient is a suitable candidate for FUE or not. In FOX test, the surgeon takes out a few (about 100) grafts from the donor area and then evaluates how many complete/incomplete follicular units are extracted. If the extraction is easy and complete units are extracted, then the surgeon should go ahead with FUE; otherwise shift onto strip technique.
According to the ease and completeness of extracted grafts, Bernstein and Rassman classified FOX test into five grades. Grade 1 is when intact follicular units literally pop out of the scalp or when there is only occasional transection of individual hairs in the unit. In Fox grade 2 patients, extraction may be relatively easy in the first session, but in subsequent procedures (when the donor area is slightly scarred) it becomes more problematic and the yield starts to decline. In these patients, the longterm yield can be compromised and planning extremely difficult. In FOX grade 3, the emergent angle is difficult. Rassman and Bernstein enrolled 200 patients in a study to assess their candidacy for FUE. They found that 74% of all the patients were either FOX 1, FOX 2 or FOX 3. The description for each category was vague and allows for considerable individual physician discretion and interpretation. In Fox grade 4-5 (when it is almost impossible to predict the emergent angle), the yield is too low for the FUE procedure to be successful. Here, the decision not to use FUE should be straightforward as the transection rate would be too high. If the patient is FOX-positive (grade 1–3), the surgeon can go ahead with FUE in the indications below mentioned.
