Chapter 9 – Follicular Unit Extraction
Although single-strip harvesting is the most efficient means of obtaining tissue for Follicular Unit Transplantation, it produces a linear scar in the donor area. With good surgical planning and meticulous techniques, FUT usually results in a very fine scar. However, if the donor strip is too wide, the patient’s scalp is too tight, or poor techniques were used in either the strip removal or the closure, a widened scar can result.
Just as the poor surgical methods of the older hair transplant techniques produced a pluggy, corn-row appearance in the front of the scalp, they often left unacceptable scars in the back of the head as well. Fortunately, with properly performed modern follicular unit transplant procedures, the pluggy look has been eliminated and donor scars are no longer a significant problem. However, it is still important to be able to avoid a linear scar in certain situations and to correct them when the need arises.
In the latter half of the 1990s, doctors set out to find a way around the linear scar by directly extracting follicular unit from the donor area using a small punch. Dr. Ray Woods was the earliest pioneer of this procedure, but practiced in Australia and chose not share details of his technique with other physicians.
Early attempts at removing individual follicular units were frustrated by high transection rates. In Japan, Masumi Inaba used a punch to partially cut through the skin around the upper part of the hair follicle and then remove the remainder of the follicle with forceps. Inaba’s insight led Rassman and Bernstein to search for less traumatic ways of extracting entire follicular units and to develop a test to predict which patients might be best suited for this technique. This research eventuated in the first publication on the subject in 2002 titled “Follicular Unit Extraction: Minimally Invasive Surgery for Hair Transplantation.”
What is FUE?
Follicular Unit Extraction (FUE) is a method of obtaining donor hair for Follicular Unit Transplantation (FUT), where individual follicular units are harvested directly from the donor area, obviating the need for a linear incision. In this procedure, a small punch is used to make a small circular incision in the skin around the follicular unit, which is then extracted directly from the scalp.
Follicular Unit Transplantation and Follicular Unit Extraction are sometimes viewed as being two distinct procedures. However, FUE is actually a type FUT where the follicular units are extracted directly from the scalp, rather than being microscopically dissected from a donor strip that has already been removed from the scalp. In other words, in Follicular Unit Transplantation, individual follicular units can be obtained in one of two ways; either through single strip harvesting and stereomicroscopic dissection (FUT) or through FUE.
When comparisons are made between FUT and FUE, what is really being compared is the way the follicular grafts are obtained. The harvesting method does have other implications for the procedure such as the transection (damage) rate, distribution of follicular units, number of grafts per session, post-op care and the total hair yield.
There are several problems inherent in removing individual follicular units with small punches. The first is that angle of the hair on the skin surface is different than the angle of the follicle below surface, making alignment difficult (see figure: Need for 3-step FUE). Any variation between the angle of the punch and the exiting hair can result in transection of the follicles. Keeping the punch perfectly parallel to the follicles throughout its entire length is nearly impossible, as the angle changes below the skin surface and the visual cues used to guide one’s hand are lost once the punch passes into the depths of the tissue. This alignment is further compromised by the twisting motion used to advance the punch.
However, the main problem with FUE is related to the anatomy of the follicular unit itself.
Follicular units resemble a small bundle of wheat gathered at the surface of the skin and splayed apart deeper in the skin, so that each follicle gently curves outward as it enters the dermis. In the subcutaneous fat, the follicles have lost their grouping and appear as individual bulbs. This curved course of the follicles through the skin is what makes the follicular unit so difficult to extract with a straight, sharp instrument like a punch.
Although a punch can neatly cut around a follicular unit on the surface, it risks amputating all or part of the widened lower portion of the units as it cuts through the deeper tissues. Trying to simply cut out follicular units with a punch, yielded results that would be anticipated from the anatomy. It produced an unacceptable rate of transection (about 30%) with wide patient-to-patient variability.
Towards a Solution
Dr. Inaba’s process of removing hair from the donor area by first using a punch to cut only part of the way down the follicular unit and then grabbing the unit with forceps so that the remainder of the follicle could literally be pulled (extracted) from the scalp, seemed to be able to circumvent some of the anatomic problems of the follicular unit and reduced follicular damage. It was soon realized, however, that even with this “extraction” technique there was considerable patient-to-patient variability in obtaining intact follicular units.
In some patients, follicular units could be removed completely intact. In others, the grafts pulled apart during their removal, resulting in the follicles being fragmented. The search began to find different hair characteristics that would account for this variability. The most obvious was hair shaft diameter. It was felt that thick, coarse hair would act to hold the graft together as it was extracted. It was also assumed that Inaba’s positive experience with the technique was based upon a select patient population, i.e., Japanese patients who characteristically have thick, coarse hair.
Unfortunately, the problem was not as straightforward as had been thought. Although successful extraction occasionally did correlate positively with hair shaft diameter, it was noted that a number of Asian patients whose grafts fragmented during extraction and some fine-haired Caucasian patients in whom extraction was relatively easy. It was apparent that other factors were involved.
It seemed that the tough, dermal layer of skin might provide strength to the graft during extraction and explain the variability between patients. In conjunction with the Department of Dermatology of Columbia University, Bernstein and Rassman began to examine the patient’s donor tissue microscopically to see what specific factors might account for differences in the ability of follicular units to be extracted. They soon started performing tests on every patient contemplating FUE to determine, in advance, of the procedure who would be good candidates. The author’s called this the “Fox Test,” an acronym for Follicular Unit Extraction.
Although the specific characteristics of a person’s scalp that determine who will be good candidates for FUE have not yet been identified, the FOX Test has been very useful in formulating a surgical plan, as it gives a great deal of information about a person’s candidacy for the FUE procedure, how much transection one might expect and even which of the two main techniques of FUE will be the most effective, the two-step or the three-step technique.
This technique has two main steps. In the first step, (the cutting part) a sharp 1 mm punch is placed over the follicular unit and aligned with the angle of the hair shafts below the skin surface. A rotational motion of the punch is then used by the hair transplant surgeon to cut through the skin and isolate FUs in the epidermis and upper dermis. When a “stop” is used to limit how far the instrument can pass into the skin, the FUE procedure is referred to as the Follicular Isolation Technique (FIT).
Success with this step depends on the ability of the surgeon to align the punch perfectly parallel to the axis of the hair shafts – a task that for reasons described above, is extremely difficult.
In step two (the extraction part), a fine rat-toothed forceps is used to apply gentle traction to the top of the FU until the unit is pulled loose from its deep dermal and subcutaneous connections. To help with situations in which the unit would not pull loose, the technique was refined further with the doctor gently dissecting away any remaining attachments of the lower portion of the graft to the surrounding skin. A fine needle, with a U-shaped tip, was the most common instrument used for this purpose.
James Harris can be credited with refining Follicular Unit Extraction by adding a third step to the process. In this new three-step FUE procedure, a sharp punch is used to score the epidermis (rather than cut through the full thickness to the dermis) and then a dull punch is used (through a back-and-forth twisting motion) to bluntly dissect the FU graft from the surrounding epidermis and dermis. The three steps are: 1) scoring with a sharp punch, 2) dissection with a blunt instrument, 3) extraction with forceps.
The main advantage that this technique has over the original two-step process is that using a dull punch as a second step avoids follicle transection and allows intact follicular units to be extracted more easily. As the blunt-tipped instrument is advanced into the dermis, splayed follicles are gathered together as they are pulled from the skin, thereby avoiding transection.
As anticipated, the three-step technique adds considerable time to an already tedious FUE procedure, but its superiority over the two-step procedure in avoiding follicular transection and in preserving follicular units makes this increased effort worthwhile.
An unanticipated problem with the three-step technique, however, is a higher incidence of buried grafts. Buried grafts occur when grafts are inadvertently pushed into the subcutaneous tissue during FUE.
These grafts can be left alone, but they may develop into cysts that may eventually need to be removed. They can sometimes be extracted using a small instrument called a Shamberg extractor (the instrument used by dermatologists to remove black-heads), but often the doctor must widen the punch-hole so that the buried graft can be grasped with forceps and pulled out. Removing buried grafts is extremely time-consuming. If one has a buried graft rate over a fraction of a percent, it becomes a significant logistical problem for the hair transplant procedure.
Clarification on Terminology
Since the extraction process is common to both procedures, in future publications, the “steps” will refer only to the aspects of the procedure that precede extraction. Therefore, the two-step procedure (that uses cutting as the first step) will be referred to as the one-step technique and the three-step procedure (that uses scoring and dissection as the first two steps) will be referred to as the two-step technique.
The Advantages of FUE
The reason for developing Follicular Unit Extraction was to eliminate the linear scar that resulted from strip harvesting. However, because properly performed FUT results in a linear scar that is usually very fine, it is important to carefully weigh the pros and cons of FUE when considering it as an alternate procedure. In other words, one must weigh the relative advantage of not having a linear scar in FUE against the relative disadvantage of having less transplantable hair. Rather than just listing the pros and cons of FUE vs. FUT, it is more useful to look at the perceived advantages and disadvantages in the context of the entire hair restoration process.
FUE is mainly considered in those who want to wear their hair very short on the back and sides, or in patients who want to shave their heads – generally, the desire of younger patients. If a person wants to shave their head after a hair transplant, or even wear their hair very short, one can argue that a hair transplant should not be considered in the first place. After all, the purpose of the transplant is to have hair, and if a person feels that a buzz cut or a shaved head is their desired look, then they should just do it.
There is a misconception that FUE is a scar-less procedure. The fact is that FUE produces more total scarring than FUT (over twice as much). It is just that the individual scars in FUE are tiny, but they are distributed over a much larger area. In fact, in most cases of FUE, a person can not shave their head, as the small round white scars of FUE would be visible.
FUE is felt to decrease healing time. The reality is that the small open wounds of FUE tend to ooze and crust for a number of days after the procedure, whereas the incision of a strip FUT is sutured closed, so that the oozing subsides by the next day. On the other hand, the linear incision of FUT takes weeks to months to regain its full strength, whereas in FUE the strength of the donor area is never compromised. If a person is engaged in contact sports and needs absolute minimum disruption from this activity, then FUE would be preferable.
It is also felt that FUE is more easily disguised after surgery than FUT; however it is just the opposite. In FUT, a thin strip of donor hair in the back of the scalp is clipped short before it is harvested. But that clipped hair is the part that is removed and the uncut areas are sewn together leaving no trace of the procedure (if the hair on the back and sites are worn a little long).
In contrast, to perform FUE, the surgeon must clip larges areas of donor area prior to harvesting the hair. As a comparison, the area of scalp needed to harvest 1000 grafts with FUE is about 60 cm, about 6 times the area needed for a comparable number of grafts when FUT is performed. And, where the harvested area is FUT is removed and sutured closed, the clipped area in FUE is harvested, but not removed, leaving a large are of mottled scalp to heal.
FUE can be performed in a person with long hair, with the sides shaved in strips, so that it can be covered by the hair around it, but this still presents a problem with visibility, since the open area is not removed. In addition, this necessitates even smaller sessions in a procedure that is already somewhat inefficient (as will be discussed).
There is some discomfort in the donor area following a strip incision, particularly when staples are used for the closure, but it is temporary and can be controlled, if needed, with medication. This is little to no discomfort in the donor area following FUE and neither FUE nor FUT procedures cause any post-op discomfort in the recipient area.
Follicular Unit Extraction may be useful for those patients with a greater risk of donor scarring, such as Asians and African Americans. However, because of the decreased over yield from FUE, it generally is more useful to switch to FUE in those patients who have a problem, than to treat all patients with FUE preemptively. In patients who are known to heal with wide or thickened linear scars, any hair transplant procedure should embark upon with caution, if at all.
FUE is often the best treatment for widened scars resulting from traditional strip excisions. If the widened strip was do to poor surgical techniques, than a meticulous re-excision may solve the problem. If however, the initial techniques were good, then re-excision would expect to give a similar result and the surgeon should go directly to FUE.
In fact, FUE can be used to improve the appearance of any linear scar and can serve as the final step after all strip sessions have been completed if the patients want to wear his hair as short as possible. In this way, the patient benefits from the efficiencies of strip-harvesting and gets a final “touch-up” of the donor scar with FUE.
FUE provides an alternative to a strip excision in patients with a very tight scalp, but it must be kept in mind that patients with a tight donor scalp may also have more limited donor reserves. The reason is that a loose scalp not only represents increased scalp laxity (i.e. ability to stretch), but also represents increased movement due to redundant scalp – extra tissue containing hair. The point is that patients with a tight scalp may have limited donor reserves than may not be correctable with FUE.
An interesting aspect of FUE is the ability to extend the size of the donor area, since it can potentially access areas that ire inaccessible with a linear excision, such as lower on the back of the scalp (where the risk of a stretched scar increases) and closer to the temples or the ears. The finer hair obtained from these marginal areas (or other parts of the body) may be useful for specific aesthetic purposes such as in eyebrow restoration, or to soften the frontal hairlines in female hair transplantation. A problem, however, is that as you move away from the middle of the donor area, the quality of the hair decreases and the hair may not even be permanent (to be discussed).
FUE makes it possible to harvest non-scalp hair, i.e. ex. beard or body hair that can be used for the cosmetic areas just mentioned. This hair can also be transplanted to the scalp to complement the hair taken from the traditional donor areas. This hair, however, is not a good match for scalp hair and offers only marginal cosmetic benefit. In addition, the fine, white scars on the body that remain from FUE can be a cosmetic problem in itself.
Limitations of Follicular Unit Extraction
The main disadvantages of FUE, when compared to FUT, is that it is less efficient in harvesting hair from the mid-portion of the permanent zone and that is causes more damage to the follicular units that are removed. The beauty of Follicular Unit Transplantation, using strip harvesting, is that the donor tissue is taken from the optimal (central) part of the donor region, so the best quality hair is used for the restoration.
In FUE, hair is extracted, but the intervening bald skin between the follicular units is not removed. Therefore, the surgeon must leave enough hair in the area to cover the remaining donor scalp. Consequently, there is considerably less total donor hair available, perhaps half as much as with FUT. This represents a significant disadvantage, since a limited donor supply is the main factor that prevents a complete hair restoration in many patients.
To compensate for the inability to harvest all the hair from the mid-permanent zone, the surgeon performing FUE must extend the harvest into sub-optimal regions of the scalp, such as from the upper and lower margins of the original donor area, where the hair may not be permanent.
The wounds in Follicular Unit Extraction, although small, are left open to heal, leaving hundreds to thousands of tiny scars. Although not readily apparent, this scarring distorts adjacent follicular units and makes the extraction in subsequent sessions significantly more difficult. For doctors with limited experience in performing FUE, this problem may not be readily apparent, but it represents a significant problem that restricts the total hair available for the restoration. FUE initially allows patients to wear their hair very short but, after large numbers of graft are extracted, fine stippled scars may become visible due to the thinning of the donor area.
Although three-step FUE significantly decreases the amount of transection and damage compared to the two-step technique, the inability to fully access the mid-portion of the permanent zone significantly limits the total amount of hair that can be accessed through FUE, rendering it a far less robust technique than strip FUT for moderate to advanced hair loss.
Another major disadvantage of FUE is that there is invariably greater follicular transection (damage) with this procedure compared to FUT. The difference is less with the three-step technique but is a significant problem never-the-less and this, combined with the inability to harvest all the hair in the central potion of the donor area makes the total hair yield in the follicular unit extraction procedure markedly less than with the strip harvesting of FUT.
The problems of increased follicular transection and the difficulty in preserving intact follicular units with the FUE technique were discussed earlier in this chapter, but a few other issues warrant discussion. The use of the stereo-microscope to dissect follicular units from the donor strip is makes Follicular Unit Transplantation uniquely suited for literally every hair type. With a skilled team of dissectors, there is essentially no difference in the transection rate between coarse, straight Asian hair, the fine, blond hair characteristic of Scandinavians and the tightly kinked hair of the African races.
On the other hand, kinky or very curly hair presents specific problems for follicular unit extraction, as does white hair, hair that is very fine, or patients with very soft scalps. In each of these cases and in some situations that we just don’t yet understand, the extraction technique can be extremely difficult. And although the FOX test can identify some of these patients in advance, even region to region variability in the same person’s scalp can present an unanticipated problem for the surgeon.
Another important limitation of FUE is that in this procedure, the grafts are more fragile, since they don’t have as much protective tissue around them as the microscopically dissected grafts of FUT. Therefore, the grafts of FUE are more subject to drying, warming and mechanical trauma during the hair transplant process. Specifically, FUE generated grafts often lack the protective dermis and fat present around the follicle – the tissue that can be preserved by careful dissection using the stereo-microscope.
An additional problem is that, during the extraction attempt, the epidermis and upper dermis may separate from the rest of the follicle. This phenomenon has been called “capping” and is unique to the follicular unit extraction technique.
With FUE, it is more difficult to capture the entire follicular unit, particularly if the hair in the unit has greater splay or the follicular units are especially large (i.e. contain 4 hairs). Yet, it is these large naturally occurring follicular units that, when kept intact, allow FUT procedures to produce gradients of density.
In FUT procedures, the dissected strip yields a normal distribution of 1-, 2- 3- and 4-hair units, exactly as it grows. With FUE there is necessarily a selection process by the doctor who picks and chooses the units that are easiest to remove. This inevitably leaves the surgeon with a distribution of grafts different than that what occurs naturally. There is a tendency is for the doctor to attempt to remove the larger follicular units, as this will yield the most hair, with the fewest number of holes in the donor area. The consequence of this however is that there are often too few single hair grafts for the hairline and, as a result the doctor must split up the larger units to artificially create the one-hair grafts. This is magnified by the fact that FUE procedures are, in themselves, small in regard to the number of grafts used compared to strip FUT procedures.
Another problem is that some doctors performing FUE place the dissected grafts immediately into the recipient scalp, without first examining them under the microscope. This short-cut saves time, but does not enable the doctor to remove hair fragments that can become inflamed and it does not insure that every graft placed at the frontal hairline will only contain one hair – as multiple hair grafts at the hairline can pose a significant cosmetic problem for the patient and can’t always be identified without the microscope.
Because, in FUE, the grafts are extracted one at a time from the donor area, it is very difficult to do steps in parallel. In contrast, with FUT, once the donor strip is removed from the back of the scalp, half-dozen skilled technicians can dissect the tissue at one time. This necessarily makes FUE a much slower process and limits the size of the session. As a consequence, FUE often requires multiple sessions to equal the size of a single FUT procedure and the entire restoration takes much longer to complete.
Return to the Introduction »»
Table of Contents
|Chapter 1||Brief History of Hair|
|Chapter 2||Hair and Its Functions|
|Chapter 3||Causes of Hair Loss|
|Chapter 4||Hereditary Baldness|
|Chapter 5||Psychology of Hair Loss|
|Chapter 6||Hair Loss Medications|
|Chapter 7||Hair Transplant Basics|
|Chapter 8||Follicular Unit Transplantation|
|Chapter 9||Follicular Unit Extraction|
|Chapter 10||Master Plan for Restoring Hair|
|Chapter 11||Goals and Expectations|
|Chapter 12||Numbers of Grafts Needed|
|Chapter 13||Hair Transplant Repair|
|Chapter 14||Hair Loss in Women|
|Chapter 15||Hair Systems and Camouflage|
|Chapter 16||Preparing for a Hair Transplant|
|Chapter 17||The Hair Restoration Procedure|
|Chapter 18||What to Expect Following Surgery|
|Chapter 19||Hair Transplant Fallacies|
|Chapter 20||Choosing Your Doctor|
|A Final Note|
|About the Author|