Bernstein Medical - Center for Hair Restoration - Four-Hair Follicular Unit
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Q: Dr. Bernstein, I think that you have established a great monument in the history of hair transplantation. Especially, your historical works about Follicular Unit Transplantation, which you published about 15 years ago, have contributed greatly to the spread of modern hair transplant technique in the whole world.

In the past days, there might have been many physicians who did not care much about the importance of the follicular unit and they have only cut the grafts to size. Now, every hair transplant physician believes the importance of follicular unit, and there is no one who cut the grafts to size ignoring each follicular unit.

However, there are some physicians who shout that a hair transplant procedure can be called FUT only when people use all single FU exclusively, and the procedure cannot be called FUT, if mixture of single FU and double FU are used in a session.

I would like to ask you, if you could accept the usage of combination of single FU and double FU under the name of FUT, as long as the grafts were cut according to each FU and intact FU are used throughout the procedure. Could you accept easing of the very strict definition of FUT, which you published about 15 years ago? Could you agree to use mixture of single FU and double FU under the name of FUT? — N.W., Huntington, N.Y.

A: Thank you for the kind words. In thinking about hair transplantation in general, it is important to consider that a hair restoration procedure spreads hair around and, as a result, the transplanted hair will be less dense than the person’s original hair. Therefore, one would never want grafts larger than the largest original follicular units or the results will not look natural. The artificially large grafts will stand out in relatively thin surroundings. If one were to try to fix this by transplanting the doubled FUs very close together (over one or more sessions) one risks running out of grafts for other areas of the scalp. In other words, you can’t fool mother nature.

For example, if a person has thin hair and has only 1-, 2- and 3-hair units occurring naturally in his scalp, then creating 4-hair grafts (by combining two 2’s or 1’s and 3’s) can result in an unnatural, tufted look. Doubling larger follicular units also necessitates larger wounds to receive the grafts which defeats one of the main advantages of FUT, namely to minimize recipient wounding.

That said, it is not unreasonable to place two 1-hair FUs in a single site (if there are extra 1s from the FU dissection) in order to increase density in an area and to eliminate an extra wound.) We do this for crown hair transplants when we are not doing a hairline and there is no need for 1-hair grafts. However, this is the exception.

Technically speaking, anything other than transplanting individual, naturally occurring follicular units is not FUT. However, a physician should make modifications to the procedure for the specific needs at hand. This is the art of medicine. By understanding and applying the underlying principles of Follicular Unit Transplantation, rather than being limited by its nomenclature, the physician will serve his patient best.

In addition to exploring Hair Restoration Answers to learn more about this topic, visit the Follicular Unit Transplant (FUT) section of our website and read detailed information about the hair transplant evaluation, the hair restoration procedure, follicular unit grafts, the donor area, and more.

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Q: I have had thinning eyebrows since my early twenties (I am now 32) and they have gotten to the point that I can’t make them look good with mascara anymore. I am considering an eyebrow hair transplant, how is it different from other hair transplants? — C.C., Williamsburg, N.Y.

A: Eyebrow hair restoration procedures are similar to hair transplants to the scalp in that the hair, once transplanted, is permanent. They differ both in the techniques used to perform them and in the results.

In eyebrow transplants, only individual hairs should be used, whereas follicular units containing from 1 to 4 hairs are used in a hair transplant to the scalp. In eyebrow transplants, the hairs must be positioned to lie as flat as possible to the surface of the skin. In hair transplantation to the scalp, the angle between the hair and the scalp surface can be as much as 45 degrees or more.

As with hair transplants to the scalp, the hair transplanted to eyebrows will continue to grow and must therefore be cut. However, in contrast to hair transplants where the donor hair is generally a perfect match for scalp hair, in eyebrow transplants the hair is taken from a different part of the body and will have slightly different characteristics both in growth rate and in appearance.

Visit our eyebrow transplant page for more information on eyebrow transplant and restoration procedures.

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Q: Some surgeons are doing hair transplants using 5,000 to 6,000 grafts in a single surgery. Looking at the cases in your photo gallery, it seems like your hair transplants involve many fewer grafts per surgery. Do you do such large graft numbers in a single hair restoration procedure? — H.P., Cranston, R.I.

A: The goal in surgical hair restoration should be to achieve the best results using the least amount of donor hair (the patient’s permanent reserves) and not simply to transplant the most grafts in one session. In my opinion, although large sessions are very desirable, the recent obsession with extremely large numbers of grafts in one session is misplaced. The focus should be on results.

For example, I would prefer to have full growth with a properly placed 2,500 – 3,000 graft hair transplant session than partial growth in a 5,000 graft session. Of course, the 5,000 graft session will look fuller than 2,500 grafts but, in my experience, never twice as full, and never as full as two 2,500 graft sessions.

The ability to perform large sessions is possible because of the very small recipient sites needed in Follicular Unit Transplantation (FUT). It is one of the main reasons that we developed this procedure in back in 1995. See the first paper on this subject: Follicular Transplantation.

However, like all good things, the technique loses some of its advantage when taken to extreme.

In “very” large sessions, the long duration of surgery, the increased time the grafts are outside the body, the increased amount of scalp wounding, risk of poor growth, wider donor scars, placing grafts where they are not needed, sub-dividing follicular units, and the decreased ability to plan for future hair loss, can all contribute to suboptimal results. These problems don’t always occur, but the larger the session, the greater the risk. Therefore, it is important to decide if one’s goal is simply to transplant the maximum amount of hair that is possible in one session, or to get the best long-term results from your hair restoration.

Follicular Unit Preservation

One of the most fundamental issues is that doctors using very large sessions are not always performing “Follicular Unit Transplantation” and, therefore, in these situations the patients will not achieve the full benefit of the FUT procedure. Although doctors who perform these very large sessions take the liberty of calling their surgery “Follicular Unit Transplantation,” in actuality it is not, since naturally occurring follicular units are not always kept whole. The procedure is defined as follows: “Follicular Unit Transplantation is a method of hair restoration surgery where hair is transplanted exclusively in its naturally occurring, individual follicular units.” (see Hair Transplant Classification)

By preserving follicular units, FUT maximizes the cosmetic impact of the surgery by using the full complement of 1 to 4-hairs contained in naturally occurring follicular units. A whole follicular unit will obviously contain more hair than a partial one and will give the most fullness. Keeping follicular units whole also insures maximal growth since a divided follicular unit loses its protective sheath and risks being damaged in the dissection.

It can sound impressive to claim that you performing very large hair transplants, but if the large numbers of grafts are a result dividing up follicular units, then the patient is being short-changed. The reason is that, although the number of grafts is increased, the total number of hairs transplanted is not. A 3-hair follicular unit that is split up into a 1-hair and 2-hair micro-graft will double the graft count, but not change the total number of hairs actually transplanted. In fact, due to the increased dissection, more fragile grafts, and all the other potential problems associated with very long hair transplant sessions, the total number of hairs that actually grow may be a lot less. Please look at the section “Limits to Large Hair Transplant Sessions” on the Graft Numbers page of the Bernstein Medical – Center for Hair Restoration website for a more detailed explanation of how breaking up follicular units can affect graft counts.

Donor Scarring

Since there are around 90 follicular units per cm2 in the donor scalp, one needs a 1cm wide by 28cm long (11inch) incision to harvest 2,500 follicular units. A 5,000 follicular unit procedure, using this width, would need to be 22 inches long, but the maximum length one can harvest a strip in the average individual is 13 inches (the distance around the entire scalp from one temple to the other).

In order to harvest 5,000 grafts, one would need 5,000 / 90 FU/cm2 = 55.6cm2 of donor tissue. If one takes the full 13 inch strip (33cm), then it would need to be 1.85 cm wide (55.6cm2 / (33cm long) = 1.85cm wide) or 1.85/2.54= ¾ of an inch wide along its entire length. However, one must taper the ends of a strip this wide (you can’t suture closed a rectangle) and, in addition, you can’t take such a wide strip over the ears. When you do the math again, it turns out that for most of the incision, the width must be almost an inch wide, an incredibly large amount of tissue to be removed in one procedure.

This large incision obviously increases the risk of having a wide donor scar – probably the most undesirable complication of a hair transplant. Needless to say, very large graft counts are achieved by sub-dividing follicular units rather than exposing the patient to the risk of an excessively large donor incision.

Popping

There are other issues as well. Large sessions go hand-in-hand with very high graft densities, since you often need these densities to fit the grafts in a finite area. The closer grafts are placed together, the greater the degree of popping. Popping occurs when a graft that is placed in the skin causes an adjacent one to lift-up. When a graft pops (elevates above the surface of the skin) it tends to dry out and die. Some degree of popping is a normal part of most hair transplant procedures and can be easily controlled by a skilled surgical team, but when it is excessive it can pose a significant risk to graft survival.

The best way to decrease the risk of popping being a significant problem is to not push large sessions (and the associated very dense packing) to the limit. In a patient’s first hair restoration procedure, it is literally impossible to predict the likelihood of excessive popping and once a very large strip is harvested, or the recipient sites are created in a very large session, it may be too late to correct for this. In addition, popping can vary at different times during the procedure and in different parts of the scalp adding to the problem of anticipating its occurrence.

Even if the distribution of grafts is well planned from the outset, a very large first session may force the surgeon to place hair in less-than-optimal regions of the scalp when popping occurs. This is because the surgeon must distribute the grafts further apart and thus over a larger area to prevent popping.

Blood Flow

Particularly where there is long-standing hair loss, the blood flow to the scalp has decreased making the scalp unable to support a very large number of grafts. This is not the cause of the hair loss, but the result of a decreased need for blood when the follicles have disappeared. In addition, persons that have been bald for a long time often have more sun damage on their scalp, a second factor that significantly compromises the scalp’s blood supply and may compromise the follicles survival when too many grafts are placed in one session. As with popping, the extent of photo-damage, as seen when the scalp gets a dusky-purple color during the creating of recipient sites, often only becomes evident once the procedure is well under way.

In the healing process following the first hair transplant, much of the original blood supply returns and this makes the scalp able to support additional grafts (this is particularly true if one waits a minimum of 8-10 months between procedures). This is another reason why it is better to not to be too aggressive in a first session when there is long-standing baldness or significant photo damage and where the blood supply may be compromised.

Limited Donor Supply

Another issue that is overlooked in performing a very large first session is that the average person only has about 6,000 movable follicular units in the donor area. When 5,000 grafts are used for the 1st procedure there will be little left for subsequent sessions and limit the ability of the surgeon to increase density in areas such as the frontal forelock or transplant into new areas when there is additional hair loss.

Conclusion

There are many advantages of performing large hair transplants, including having a natural look after one procedure, minimizing the number of times the donor area is accessed, and accomplishing the patient’s goals as quickly as possible. However, one should be cautious not to achieve this at the expense of a wider donor scar, poor graft growth, or a compromised ability to plan for future hair loss.

Achieving very high graft numbers should never be accomplished by dividing up the naturally occurring follicular units into smaller groups, as this increases the risk to the grafts, extends the duration of surgery, increases the cost of the procedure (when charging by the graft) and results in an overall thinner look.

For further discussion see:

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Q: Dr. Bernstein, I remember Senator William Proxmire. He was one of the first sort of high-profile people who had a hair transplant probably, what, thirty years ago, and to be honest with you, it wasn’t all that great. It looked kind of funny. Have we made any progress in the last twenty-five, thirty years? — A.E., Fort Lee, N.J.

A: When hair transplant surgery was first developed in the late 1950s, early 1960s, everybody was so ecstatic that it grew – that one could actually move hair from the back of the head to the top, and it would grow – that no one really considered either the long-term implications or the aesthetic aspects of the procedure. And the fact that the hair grew is actually a problem because it never went away when it was transplanted poorly.

Over the years the grafts have gotten smaller and smaller. So where in the ’60s and ’70s they were the size of pencil erasers, they gradually decreased in size until doctors were performing hair transplants using just a few hairs at a time. The major breakthrough came in the mid 1990s when we realized that hair doesn’t grow individually but grows in little tiny groups and these groups are called follicular units.

In modern hair transplant surgery (which began in 1995) hair is taken from the back of the scalp and moved to the front and top of the scalp in these individual groups of one to four hairs.

In this way the results can completely mimic the way hair grows in nature.

See the Follicular Unit Transplant (FUT) section for more information.

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Q: What is Follicular Unit Transplantation and how is it different from Follicular Unit Extraction? — H.L., White Plains, NY

A: Follicular Unit Hair Transplantation, called FUT for short, is a procedure where hair is transplanted in the naturally occurring groups of one to four hair follicles. These individual groups of hair, or units, are dissected from a single donor strip using a stereo-microscope. The area where the donor strip was removed is sutured closed, generally leaving a thin, fine, line scar.

In Follicular Unit Extraction, or FUE, the individual units are removed directly from the back or sides of the scalp through a small round instrument called a punch. There is no linear scar. There is, however, scarring from the removal of each follicle. Although the scars of FUE are tiny and round, the total amount of scarring is actually more than in FUT.

In addition, since in FUE the bald skin around each follicular unit is not removed, the total amount of hair that can be removed in FUE is substantially less than in FUT. This is because if one were to remove all the hair in an area, it would be bald. In FUT, the intervening bald tissue is removed along with the follicles in the strip.

Read our page on FUE vs. FUT

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