Case 10: What is the difference between FUT and FUE? - Bernstein Medical - Center for Hair Restoration

Case 10: What is the difference between FUT and FUE?

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April 22nd, 2022

A 56-year-old male presents with progressive thinning since age 25 and is interested in a hair transplant. He has no significant medical history. On examination, he has an early Norwood 7 pattern of hair loss. His hair is straight, brown in color, and medium-fine. He has a relatively loose scalp. His donor density is 2.1 hairs/mm2. He is interested in robotic FUE because he was told that it is “non-scarring.” His local dermatologist began finasteride 1mg/day over two years ago and he is compliant and has no side effects.

 
Question 1: Which are true about hair transplants?

  1. Only FUT causes scarring.
  2. Only FUE causes scarring.
  3. Both FUT and FUE cause scarring.

Answer: C. Both FUT (Follicular Unit Transplantation via strip harvesting) and FUE (Follicular Unit Excision) procedures leave scars. While FUT leaves a linear scar where the donor tissue was harvested, FUE leaves very small (approx. 1mm) round scars at each site where the follicular units are removed. In fact, to emphasize the surgical (and scarring) nature of FUE, and to avoid any confusion by the public, FUE in now referred to as Follicular Unit Excision (rather than Follicular Unit Extraction).

 
Question 2: Which procedure gives a more natural result, FUT or FUE?

  1. FUT
  2. FUE
  3. The same

Answer: C. FUT and FUE refer only to the method of harvesting donor hair. Other aspects of the hair transplant procedure are the same. Although FUT generally results in a fuller appearance (reasons to be discussed), both FUT and FUE procedures will look equally natural, since both use individual follicular units (rather than larger grafts) in the procedure. This, of course, assumes that the physician has good aesthetic judgement and that the surgical planning and techniques are performed properly.

 
Question 3: Which hair restoration procedure would be recommended in this patient if his primary goal is to achieve the most coverage, FUT or FUE, and why?

  1. FUE, since his donor density is high and there is a significant area of stable donor hair available from which to harvest individual grafts.
  2. FUT, since his donor zone is narrow, higher graft numbers can be obtained with removal of a strip.
  3. His pattern of hair loss does not impact the choice of procedure and he will obtain similar coverage results for either surgery.

Answer: B. This patient will get the most coverage with a Follicular Unit Transplant (FUT). The most permanent donor hair resides in a relatively narrow horizontal band at the back and sides of the scalp. The FUT procedure uses a long, thin, linear strip, to remove hair only from this region. It is particularly efficient when there is a limited rim of hair. In Follicular Unit Excision (FUE), only a fraction of the hair in the most stable region of the donor zone can be harvested, or the area will appear too thin. In FUE, areas from outside the permanent zone must often be used to get the desired number of grafts.

An equally important reason that you get more coverage with FUT (compared to FUE) is that in FUT the entire follicular unit is preserved through stereo-microscopic dissection of the donor strip. In contrast, in an FUE procedure, the follicular units are literally punched out of the scalp. In the process, some follicles are transected, and the follicular units are often stripped of all or part of their protective sheath, contributing to sub-optimal growth. This is a limitation of all FUE procedures, regardless of how sophisticated the method of extraction.

 
Question 4: How does the degree of scalp laxity (looseness), change one’s preference for FUT vs FUE?

  1. A loose scalp would make FUT more challenging if the scalp laxity (looseness) is due to high scalp elasticity.
  2. A loose scalp would make FUE more challenging if the scalp laxity is due to high scalp elasticity.
  3. A loose scalp is a great advantage for FUT if the scalp is redundant rather than elastic.
  4. A loose scalp does not pose a significant challenge for FUE if the scalp is redundant rather than elastic.

Answer: All the above. To answer this question, it helps to understand the components of scalp laxity and the terms used to describe them. Scalp looseness (or laxity) is simply the mobility of the scalp i.e., the ability to move the scalp with one’s hand. Scalp laxity (looseness) has two components: scalp elasticity (the stretchability of the scalp) and redundancy (extra scalp tissue).

High scalp elasticity makes FUT more challenging as the donor scar is more likely to stretch during the healing process resulting in a widened scar. High scalp elasticity also makes FUE more difficult because the scalp is difficult to stabilize (increasing transection) and the graft itself tends to shear in the extraction process. A redundant scalp makes FUT easy as there is plenty of donor hair to be excised through strip-harvesting, without causing undue tension. FUE can easily be performed in a redundant scalp if there is no concomitant increased elasticity.

In sum, when scalp looseness is due to increased elasticity, both FUT and FUE are more difficult; however, when scalp looseness is due to redundancy, the success of FUE is generally unaffected, but FUT becomes easier to perform. Determining whether increased scalp laxity is due to elasticity or redundancy (or both) requires a significant amount of clinical experience, but it is extremely important to the surgical outcome.

 
Question 5: The patient has fine hair on examination. How would this change your management?

  1. FUT is a good procedure for fine hair as the grafts can be carefully dissected under microscopic guidance to preserve follicular units.
  2. Fine hair is easier to remove with FUE since the graft is thinner and more easily targeted for individual removal without damaging the integrity of the follicular unit.
  3. Fine hair is not a challenge with either procedure.

Answer: A. Fine hair is more challenging to harvest with FUE since the grafts will be more delicate and more difficult to remove. Fine grafts are more easily transected or fragmented during extraction. FUT overcomes this challenge through careful microscopic-guided dissection of grafts which allows thin fine hair to be gently dissected from the dermis with the appropriate amount of surrounding support tissue.

 
Question 6: The patient states that he has kept his hair cropped short because he is so bald, but he is open to different length hairstyles if he had more hair on top of his head. With this knowledge, you should inform him that:

  1. If he elects to do FUE, then he can keep his hair cropped short, but will have a limited amount of coverage.
  2. If he elects to have FUT then he would need to keep his hair longer on the sides to hide the linear FUT scar.
  3. With either FUT or FUE surgery, full coverage will not be possible.

Answer: All the above. In a Norwood 6 or 7 patient, full scalp coverage will generally not be attained with either type of procedure due to the large area of hair loss and the limited amount of donor hair. The advantage of FUE is that you have the flexibility in styling to keep the sides and back very short, although the degree of coverage in the transplanted area will be more limited. The advantage of FUT, is that you will have better yield and a fuller transplant, and this benefit will be compounded if one wears the hair longer.





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