Follicular Unit Extraction/Donor Management & Punch Size
The safety zone for FUE can be measured and sectioned in to three areas; simply both sides and the back, then the total surface area calculated. The density is then measured in each area and an average overall density taken using a magnifying densometer; the natural FU groupings measured and an average taken including miniaturisation of hair in the donor safety zone.
The number of grafts available for extraction can then be calculated; taking into consideration not over harvesting and leaving the donor “moth eaten”. To ensure not to over harvest there must be a limit to the number of FU that can be removed per cm2; removing much more than 27% per cm2 will noticeably thin the donor area and potentially cause obvious visible scarring over a large area of the donor.
The punch size used will affect the number of FU that can be safely removed; incorrect punch can increase transection of the removed FU, damage surrounding FU cause larger and more visible scarring. With a small punch there is a risk of transecting the FU being removed if the group is too large to be encompassed by the diameter punch, therefore cutting the FU causing the loss of a hair from that FU and reduce the total hair numbers placed. When a large punch is used it has the possibility to cut into an adjacent FU if the density of FU is high. This either means taking two genetic groups at the same time or splitting and transecting one of them, for example two 2 hair FU or maybe a 3 hair and a 1 hair in the same punch OR maybe taking an intact 3 hair FU and dissecting another and a likely conclusion is killing a hair and traumatising the surrounding hairs.
Included in this problem is the pattern of extraction; to use a large punch and over harvest in an area will leave obvious thinning and density changes in the donor; this will result in the donor potentially being too thin for further extraction even from a relatively small number being removed; say 2000; this has been called “hairless areas” but simple is larger scarring be it obvious or not OR overharvested areas.
The larger the incision made into skin has the potential for greater scarring; obviously the skill of the incision will have an impact but simply a larger hole is made in the skin tissue and more fibrosis is caused and greater pigmentation alteration; thus making the scarring potentially more visible and larger. If the larger punch is used and the extraction pattern not monitored to approximately 27% the donor can visibly lose density, because a “moth eaten” look on the scalp and make it almost impossible to harvest any amount of grafts.
Below is a section of a report made with Dr Bisanga a few years ago discussing the FUE procedure and the pros and limitations; it shows the effect of a 1.1mm punch on the surrounding FU and smaller punch on larger FU groups; also that a .75 mm punch can surround a 4 hair FU without transection and thus cause less potential scarring.
Follicular Unit Extraction when the limitations are adhered to can be an excellent form of hair transplant. The limitations are the use of the correct punch size, not to extract a combination of FU in one punch; not to over harvest the donor to extract more FU and leave the donor thinned.
As noted by H&W, most FU are grouped in an elliptical fashion rather than cylindrical. Is it possible to develop a “squashed” elliptical punch? Have you used different shaped punches?
what percentage of the safe area is removed by strip? Is it greater than 27%?
Dies it really matter if the superficial follicle (at the dermal interface) is transected as long as the deeper structures are kept intact? Dr. A and Dr. Harris uses expanding needles and blunt dissection to deal with this. What do you think.
A very good point indeed Marco. Except what is the expanding needle concept?
Blunt dissection does a good job with splay. And Harris has shown that.
Bisanga has shown good results with his 0.75mm punch and it being sharp only.
But you bring up a good point about transections at the dermal layer. Does it matter? Not if the follicle is left intact and left behind. I don’t know if anyone can really prove anything about this with the exception of this study by which Bisanga might have a point that a larger tool could provide a MORE potential for damage to a peripherally transected graft as apposed to using a smaller diameter to encompass the follicle only.
Now the argument is that a FUE using a smaller punch WILL also provide a certain amount of transectioning… more so than the blunt technique IMO, however I have to say that Bisanga has been able to show ample growth in fairly large FUE cases using the small punch. Why?
He has also shown several nice donor areas. The whole purpose of FUE was to create an alternative to a strip and to have less scarring in the mean time. Not may clinics have been able to show both good growth as well as a reduced scarring potential. Bisanga is one of the only one that has. Why?
» The larger the incision made into skin has the potential for greater
» scarring; obviously the skill of the incision will have an impact but
» simply a larger hole is made in the skin tissue and more fibrosis is
» caused and greater pigmentation alteration; thus making the scarring
» potentially more visible and larger. If the larger punch is used and the
» extraction pattern not monitored to approximately 27% the donor can
» visibly lose density, because a “moth eaten” look on the scalp and make it
» almost impossible to harvest any amount of grafts.
What is 27% ? Are you saying once you extract more than 27% of the donor it will become visibly thin?
Typically most FUE docs try to take maximum around 25-27% of the safe zone’s density in FUE. That way, in most cases there will not be a perception by the average eye of a “thinness” like you have said.
Although recently there have been strange claims of a 50%+ deficit will not be noticeable. I have never seen that amount of a drop with out a moth eaten look.
» » The larger the incision made into skin has the potential for greater
» » scarring; obviously the skill of the incision will have an impact but
» » simply a larger hole is made in the skin tissue and more fibrosis is
» » caused and greater pigmentation alteration; thus making the scarring
» » potentially more visible and larger. If the larger punch is used and
» the
» » extraction pattern not monitored to approximately 27% the donor can
» » visibly lose density, because a “moth eaten” look on the scalp and make
» it
» » almost impossible to harvest any amount of grafts.
»
»
» What is 27% ? Are you saying once you extract more than 27% of the donor
» it will become visibly thin?
I think the study prove that the use of a 0.5 mm punch is probably ill advised; of course FU are mainly in an elliptical fashion because on average they contain an uneven number of hairs; hence the average being 2.2/3 etc; but that does not mean the punch diameter has to be distorted dependent on the shape of the FU; under that principle almost every FU would require a variant in punch differential which is not true. Using a suitable size tool is adequate to be able to remove the FU and surrounding tissue whilst maintaining the integrity of the surrounding FU and the skin tissue and also keeping the removed FU intact; whilst preserving the donor area and allowing little to no obvious scarring.
IF you wanted to use an elliptical punch there is a great chance the ellipse has a grand axis and small axis so what size punch would you use to decrease scarring and preserve donor; also taking into consideration the angulations of the punch any slide to obtuse will increase scarring.
The % of movement with strip and FUE is very different and a large variant between the two procedures and a reason why they cannot be compared; you cannot compare the removal of a strip of skin tissue then sutured to marginally affecting the scalp laxity and the surface area of FU being removed even if standardised in respect of density; both techniques can live but not easily compared.
With respect to blunt and sharp as far as I am aware Dr Harris uses a sharp tool punch through the epidermis and then the use a dull punch to penetrate the dermis so he doesn’t transect the upper follicle; in that respect it has little bearing on transection; in respect of the dermal interface is irrelevant and as far as Dr A who knows, let him join the discussion.
27% of FU per cm is approx what can be safely removed without OVER HARVESTING your donor; of course you can remove more and many do under the principle that the light reflection only penetrates to the skin when approx. half is removed. While this maybe true the principle of donor management work very differently; if you are prepared to remove say 50% then any real or viable options in the future are lost;on an average density of 75 you leave the person with a density close to 35 and few to no options in the future; even with strip. If the idea is to shave it will leave very large areas of no hair and if a larger punch used scarring; and if the idea is to have more FUE in the future the area is already been over harvested.
» With respect to blunt and sharp as far as I am aware Dr Harris uses a
» sharp tool punch through the epidermis and then the use a dull punch to
» penetrate the dermis so he doesn’t transect the upper follicle; in that
» respect it has little bearing on transection;in respect of the dermal.
In the dermal interface it IS most relevant. This is where the two techniques separate from one another. Consider this Philb:
In the dermal layer, the blunt tip protects the follicular bulbs and especially splaying by decreasing the transection potential. Not completely but a lower chance.
The sharp punch in the dermal layer will always have a higher potential for transectioning. That is an absolute fact.
The downside to the blunt technique is often the two step process which slows folks down.
Bisanga has shown that the sharp punch along with the size being 0.75mm can provide good growth. This means that only a SKILLED experienced hand is able to keep a low transection rate in the dermal layer… and this is by “feel” of the hand.
So while both techniques are doable. Only experienced hands can actually do the sharp only technique. This is something I have seen with you guys hands down.
Well pretty much most FUE clinics mention something around the 25% as being to most you should take, but it is really a variable that is individual to the patient’s characteristics.
» This is the first time I have heard about this 25% rule. Do other doctors
» have the same experience?
Most clinics have their own acceptable range for harvesting. Some are more conservative, others more aggressive. 25% is not necessarily the maximum you can possibly harvest, but a general guide to help prevent over harvesting.
Also note that this rule is generalized and based only on follicular density. It does not take into consideration the number of hairs per follicular unit, thickness, curl, or overall coverage. It also does not include any changes/distortions in follicular density or geometry due to previous hair transplant. There are variations in each individual that can affect your donor availability.
It is up to the doctor to rely on his/her good judgement and experience to take these other factors into consideration when planning the surgery with the patient.
It would be a good idea to discuss this with your doctor beforehand if your donor availability is of concern. Find out how much they intend to harvest and why.
Everyone clearly understands the thinned look & unsatisfactory results of a recipient area that is only 50% density.
We may deem a 50%-density recipient area to be “acceptable” since donor hair for HTs is limited and some amount of thinning is normal for the upper half of a man’s head. But that does not mean we cannot tell the difference between a 50% or a 100% density area on top. It just means the 50% recipient area is a “lesser of evils.”
So why would the appearance & feel of only 50%-density be acceptable as “normal” in the donor area?
You can certainly find a FUE doctor to tell you that 50% density in the donor will still look good. And you can certainly pay him to take 50% out of the donor.
But you can’t make a 50% density donor area really look good to the rest of the world.
25% means the doctor only takes out 1 every 4 follicles in the donor. I think a good doctor should be able to easily remove 1 every 3 (33%) without making the donor look thin out.
There are very few cases of more than a few thousand FUE grafts.
I can’t think of ever seeing a FUE patient that had more than about 5000 grafts done. At least not with results that looked decent.
If you’ve got big numbers of hairs to move in your lifetime, then I would either bite the bullet and get strip HT work, or else wait for solid proof that HM will eventually bail you out before getting FUE work done.
Right now FUE by itself just can’t seem to produce the big numbers of grafts with good results. I don’t think that is gonna change in the future since it has not already. And FUE’s price would be astronomical in large amounts anyway.
» » How many hairs do we have in the back of our head if I want to estimate
» how
» » many I can spare at 25% or 33%. Thank you
»
» Cal said the most he has seen is about 5000 fue. If the 25% rule applies,
» that means about 20,000 in the donor.
I have seen a couple of FUE over 5000 that looked good but no idea what the extraction from the donor looked ok though in one of them. I was looking for max FUE and strip maybe because I don’t think FUE can do it all and I agree with this article that FUE will give smaller amount than strip unless you want to take take more and thin out the donor. Not something I can afford to do because of the strips I have already
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