Bernstein Medical Center for Hair Restoration - Terminal Hair

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Q: I have been reading various articles and forum postings and it would seem that a person utilizing Propecia might experience increased “shedding” of hairs (outside of the normal hair cycle) around the 12 week mark after a hair transplant and lasting around 2-4 weeks. The forum postings suggest that one will not only see the miniaturized hairs being lost, but also normal terminal hair in greater than expected levels. Does an explanation exist to explain this increase in shedding hairs? — B.T., Manhattan, NY

A: Our understanding is that finasteride only affects miniaturized hairs — i.e. hair affected by DHT — and that this is all that should be shed. Remember, however, that much of the thinning a bald person experiences is due to thousands of partially miniaturized hair, and these can look very much like a full terminal hair in its early stages.

See our page on Shedding After A Hair Transplant.

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by Jeff Teumer, PhD
Hair Transplant International Forum, Volume 18, Number 3, May/June 2008

Follicular cell implantation (FCI) is based on the ability of the dermal papilla (DP) cells, found at the bottom of hair follicles, to stimulate new hairs to form. DP cells can be grown and multiplied in a culture so that a very small number of cells can produce enough follicles to cover an entire bald scalp.

In order to produce new follicles, two types of cells must be present. The first is Keratinocytes, the major cell type in the hair follicle, and the second are dermal papillae cells (DP) which lie in the upper part of the dermis, just below the hair follicle. It appears that the DP cells can induce the overlying keratinocytes to form hair follicles. There are a number of proposed techniques for hair regeneration that use combinations of cells that are implanted in the skin. The two major techniques involve either transplanting dermal papillae cells by themselves into the skin or implanting them with keratinocytes. These techniques can be used with or without an associated matrix used to help orient the newly forming follicles.

Implanting Dermal Papillae Cells Alone

  1. Implanting DP cells by themselves into the dermis, with the hope that they will cause the overlying skin cells (keratinocytes) to be transformed from normal skin cells into hair follicles. This method is called “follicular neo-genesis” since new hair is formed where none previously existed.
  2. Cells of the dermal papillae are placed alongside miniaturized follicles. The transplanted cells would induce the keratinocytes of the miniaturized follicles to grow into a terminal hair. A potential advantage of this technique is that the existing miniaturized follicles already have the proper structure and orientation to produce a natural look growth.

Implanting Dermal Papillae with Keratinocytes

  1. A mixed suspension of cultured keratinocytes and DP cells are implanted into the skin.
  2. Keratinocytes and DP cells are cultured together such that full or partial hair formation takes place in a culture dish. These culture-grown hairs, or “proto-hairs,” are then implanted into the patient. The advantage of using a proto-hair is that there would be better control over the direction of hair growth because of the structural orientation of the proto-hair.

Cell Implantation using a Matrix

  1. A variation of the above techniques is to use a matrix to help orient the implanted cells. This could be either an artificial matrix composed of materials such Dacron or it could be a biological matrix composed of collagen or other tissue components. The matrix would act like a scaffold to help cells organize to form a follicle. If the matrix were filamentous (like a hair) it could help direct the growth of the growing follicle. A matrix could be used with dermal papillae cells alone or in combination with cultured keratinocytes.

With all of the varied approaches for FCI, the aim is to combine keratinocytes and DP cells to efficiently and reproducibly generate thousands of follicles for hair restoration. In some cases, cells are combined in vivo and all of the hair formation must take place in the body after implantation, while in others, some hair formation takes place in culture before implantation.

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Q: I am a 21 yrs old male having serious hair loss over the last few years. I also have very little facial hair. Since Propecia is a DHT blocker can it inhibit beard growth? — E.M., Astoria, N.Y.

A: As you suggest, it would be reasonable to assume that since DHT stimulates beard growth, blocking DHT (with finasteride) would tend to inhibit its growth. In practice, this does not seem to be the case, i.e. we don’t find that Propecia has any effect on facial hair. The reason is not clear.

It is interesting to note that testosterone stimulates growth of axillary and pubic hair, but not scalp hair. Scalp hair growth is not androgen dependent, only scalp hair loss is.

DHT stimulates terminal hair growth of the beard, trunk and limbs, external ears and nostrils. Of course, it also is responsible for the bitemporal reshaping of hairline as one passes into adulthood and causes male patterned baldness (androgenetic alopecia).

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Q: Why should a doctor measure miniaturization in the donor area before recommending a hair transplant? — E.B., Key West, F.L.

A: Normally, the donor area contains hairs of very uniform diameter (called terminal hairs). In androgenetic hair loss, the action of DHT causes some of these terminal hairs to decrease in diameter and in length until they eventually disappear (a process referred to as “miniaturization“). These changes are seen initially as thinning and eventually lead to complete baldness in the involved areas.

These changes affect the areas that normally bald in genetic hair loss, namely the front and top of the scalp and the crown. However, miniaturization can also affect the donor or permanent regions of the scalp (where the hair is taken from during a hair transplant). If the donor area shows thinning, particularly when a person is young, then a hair transplant will not be successful because the transplanted hair would continue to thin in the new area and eventually disappear. It is important to realize that just because hair is transplanted to another area, that doesn’t make it permanent – it must have been permanent in the area of the scalp it initially came from.

Unfortunately, in its early stages, miniaturization cannot be seen with the naked eye. To detect early miniaturization a doctor must use a densitometer, or an equivalent instrument, that magnifies the surface of the scalp at least 20-30 times. This enables the doctor to see early changes in the diameter of the hairs that are characteristic of miniaturization. If hairs of varying diameter are noted (besides the very fine vellous hairs that normally occur in the scalp), it means that the hair is being affected by DHT and the donor area is not truly permanent.

In this situation, a person should not be scheduled for hair transplantation. If the densitometry reading is not clear, i.e. the changes are subtle and the doctor is not sure, then the decision to have surgery should be postponed. By waiting a few years, it will be easier to tell if the donor area is stable. Having surgery when the donor area is miniaturizing can be a major problem for a patient, since not only will the transplanted hair eventually disappear, but the scar(s) in the donor may eventually become visible. This problem will occur with both follicular unit transplantation (FUT) and follicular unit extraction (FUE).

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Cosmetic Surgery Times features Dr. Bernstein’s presentation to the 55th annual meeting of the American Academy of Dermatology in their April 1997 issue.

The article entitled, “Follicular Transplants Mimic Natural Hair Growth Patterns,” describes Dr. Bernstein’s introduction of his new procedure, Follicular Unit Transplantation, to the academy as well as the keys to making the technique successful. Find the complete article below:

Form Follows Function: Follicular Transplants Mimic Natural Hair Growth Patterns

By Neil Osterweil
Contributing Editor

SAN FRANCISCO – In recent years, many hair replacement surgeons have adopted the modem architecture philosophy that “less is more,” moving from the use of hair plugs, to split grafts, to minigrafts and, finally, micrografts. But at least one hair transplant specialist contends that a more appropriate architectural dictum is “form follows function.”

In other words, the surgeon should let the technique fit the head, and not the other way around, suggested Robert M. Bernstein, MD, at the 55th annual meeting of the American Academy of Dermatology.

Dr. Bernstein is an assistant clinical professor of dermatology at the College of Physicians and Surgeons, Columbia University in New York. He described his “follicular transplantation” technique in a meeting presentation and in an interview with COSMETIC SURGERY TIMES.

Natural Hair Groups Used

Dr. Robert M. Bernstein“Hair doesn’t grow singly it grows in naturally occurring groups of from one to four hairs. In follicular transplantation, we use these naturally occurring groups as the unit of the transplant,” he told CST.

The typical follicular unit consists of one to four terminal hairs, one or two vellus hairs, sebaceous glands, subcutaneous fat and a band of collagen which circumscribes and defines the unit. In the follicular transplant technique, the follicular unit is carefully dissected and removed, and then the intervening skin is discarded. This enables the donor site to be small, allowing implantation through a small needle poke. Because trauma to the recipient sites is minimal, the entire procedure can be performed at one time. Dr. Bernstein and colleagues have implanted as many as 3,900 follicular units in a single, 1 day session.

Keys to the follicular transplant technique are:

• Identify the patient’s natural hair groupings and isolate the individual follicular units – Hair groupings are assessed with an instrument called a densitometer, and the average size of a person’s groups can be easily calculated. This information is critical in the planning of the transplant. The density of hairs in an individual measured as the number of hairs per square millimeter of skin is quite variable, but the density of follicular units is relatively constant within individual races.

Most people of Caucasian ancestry have a density of approximately one group per millimeter; people of Asian and African descent tend to have slightly less dense growth patterns, although the characteristics of the person’s hair (such as wavy or wiry hair), can give a full appearance even with low density.

If a patient has an average hair density of two, he will receive mostly two hair implants, with some one-hair and three hair implants mixed in. “If you try to make the groups larger than they occur naturally, they will look pluggy. If you try to make them smaller than they naturally occur, they’re not going to grow as well, because each group is actually a little biologic machine that makes the hair — it’s an anatomic unit. If you break it up it just doesn’t grow as well,” Dr. Bernstein observed.

Form Follows Function: Follicular Transplants Mimic Natural Hair Growth Patterns
A 38-year old man with a Norwood Class 5A/6 hair loss pattern undergoes a single procedure of 2,500 follicular implants. The result 11 months later. (Photos courtesy of Robert M. Bernstein, MD)

• Harvest meticulously – The acquisition and preparation of grafts must be carefully performed to ensure success for this demanding technique. Highly trained, skilled assistants are essential to the success of the procedure. Dr. Bernstein noted that he uses a highly trained team of up to 10 assistants to produce the implants for a single case. “The assistants, who range from medical technicians to registered nurses, are such an integral part of the procedure that they must become expert in their specific tasks for the surgery to be successful.” The physician must be able to skillfully harvest the donor strip and must be able to make accurate judgments about the size of grafts intra-operatively and adjust the technique accordingly. Dissection and placing of the follicular units is the most labor intensive part of the procedure.

• Design the recipient area well – The recipient sites are carefully distributed so that a natural looking pattern is maintained throughout the recipient area. An important consideration for this stage of the procedure is to “frame the face and spare the crown” so those facial features are kept in correct proportion. A common mistake in hair replacement, said Dr. Bernstein, is to create a hairline that is too high thereby elongating the forehead and accentuating, rather than minimizing, the patient’s baldness. It is also important to avoid or eliminate contrast between the implants and surrounding skin by creating a soft transition zone of single hairs and to have the hair emerge from the scalp at natural angles.

Procedure Lowers Cost

Although the procedure is highly labor intensive, it can actually be less expensive than conventional hair replacement surgery, because it can be performed in a single, but lengthy, session.

“It is also much more efficient and conserves donor hair much better than conventional hair transplants. Every time you make an incision in the person’s scalp you waste some hair and make the remaining hair more difficult to remove. Accessing the donor area just once or twice will increase the total amount of hair that is available for the transplant,” Dr. Bernstein told CST.

“In the very near future, the procedure will be improved and made more affordable with automated instruments that will enable the surgeon to make sites and implant the hair in a single motion. This will also decrease the possibility of injury to the implants by reducing handling and keeping the grafts uniformly cool and moist. It is possible that someday hair follicles may be cloned to provide a virtually unlimited supply of custom follicular units, but until then the finite nature of a person’s donor supply must be respected,” concluded the doctor.

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