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cameron-is-God.
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Hair Transplant Density - Dr. Cole
Interessante: good reading!
Density is a function of the incision size.
There is a simple formula.
The distance between the grafts in millimeters is equal to the a constant, 10.7, divided by the square root of the density in sq. cm.
The distance between grafts at 80 per sq. cm is 1.12 mm.
The diameter of a single hair is 0.42 mm on average.
Two hairs average 0.8 mm and three hairs 1.2 mm.
In order to pack 80 per sq. cm, you need to make very tiny incisions and place very small grafts that are aggressively trimmed.
In other words, there is a trade off between trauma, size of the graft, the incision size, and the comfort of the fit.
Is it acceptable to compress a graft too tightly? Does the yield go down? Is it better or worse to force a graft into an incision size that is too small?
No one knows these answers.
There are other concerns, as well. When doing body hair transplants, I am always amazed at how many new hairs show up in the same area that I picked clean the year before. There are always hairs that are very hard to see because they are early anagen hairs or exogen hairs that are so microscopic that you cannot see them with the naked eye. This occurs with scalp follicular units, as well. Aggressive trimming risks loosing these hairs and tossing them in the waste.
Most strip harvested grafts have fat on them. This additional fat takes up volume. With FUE, we have no fat so we do not have the extra volume. This extra volume can cause a couple of problems. One is ridging. The other is that they take up space in an already small incision site. Therefore, fat in a small incision site can make the placement even more traumatic.
Even with no fat, I find the most comfortable density for my full size grafts is 40 to 50 per sq. cm.
I go higher, with single hair grafts, or well trimmed 2 hair grafts, but with full size follicular units, I average 45 per sq. cm. With body hair, I average 70 per sq. cm. Numbers are critical with body hair. We need higher densities to achieve the fullness we are looking for with body hair. Most of my FIT cases come in for multiple days. One of the tremendous advantages here is that I am able to go back into the area the next day or several days later and increase the density so full that it is not possible to squeeze in another graft without overlapping incisions.
My scalp grafts average 2.5 hairs per follicular unit. Strip surgery averages only 2.3 hairs per follicular unit. What happened to the other 8%, you may ask. With body hair we average less than 2 hairs per graft. Therefore, smaller incision sites are more practical and we get the higher densities we need. The smaller the incision, the harder it is to place the multi-hair graft and the more traumatic it is to place the graft.
It is easy to say you pack at 80 per sq. cm. It is entirely different to actually do it and to achieve good growth.
There are other factors to consider. Many of my patients come to me for scar repair or hair transplant repair surgery. Lets face it. There are almost 50 years of hair repair surgery cases out there. I don’t know anyone doing what we are doing with hair repair surgery. This is an entirely different situation that requires specialized solutions that are often customized. Grafting into these areas may result in a lower yield if you go for a super dense packing. One must always individualize the case and customize the procedure so that it works in the best interest of the patient. We are not interested in setting any world records or marketing ourselves based on the current flavor of the day. What our patients are interested in is results. Results are how we promote techniques. We’ve done that for over 15 years
Other factors control yeild. One of these is the pH of the storage solution. We constantly monitor our storage solutions and change them every hour.
Most physicians use normal saline. this has a much lower pH than the body.
This pH decreases as grafts metabolize outside the body in an anaerobic medium. as they do this, the cells make hydrogen atoms that reduce the pH further.
We start with a solution that is about 7.4 in pH or about the same as the human body. we monitor the solution and change it every hour.
This is a much more healthy environment for hair and we are convinced it produces a better yeild in the long run.
More hair per graft, a higher yeild, and a better overall result. This is our mantra.
Ulteriore, splendido contributo di Cole (I love you, John!):
I fully recognize the cost limitations to hair surgery. Suffice it to say that i do my best to incorporate patient budgets into my surgical plan. If every patient paid us for every graft, we could not achieve the results we want. Results are just as important to us as they are to our patients. We do our best to modify our pricing as we progress with our patients. With additonal proceudures, we often re-organize pricing so that our patients can afford to get the best result. It is important for patients to let us know where they stand financially. We are not mind readers. We also often go beyond the call of duty in terms of grafting so that our patients get the best result. It is always a complaint when we show procedures with thousands and thousands of grafts on these message boards. what we rarely mention is that not every graft is always paid for.
Donor depletion has always been a concern for us. It is a concern for my strip patients and it is a concern for my FIT patients. I have long recognized the primary problem with FIT. This is that when we move a follicular unit from point A to point B, we leave a gap. Under most instances this is not a concern. even when you shave to a bic, this is rarely something that people notice. I notice it because i look very closely at the geometry of the donor area. if minor changes are present, i notice them. This is my job, however, and I am expected to notice them. In an effort to reduce the gaps, I have done many things. One of these things is to employ a new latex or silicone gel elastic compression that compresses the gaps closer to on another. The other thing has been to rotate BH into the gaps so that they donor area remains more pristine. This idea is not new to us. We first conceived it over 2 years ago, but we put it into practice only recently because it is only recently that we've felt it was important to implement this process. We also wanted to insure that body hair would grow well on the scalp prior to inacting this process. I primarily employ it for patients who have extensive scarring in the donor area and for patients who have had multiple FIT sessions. Patients with extensive scarring need replenishment of thier donor area when we want to utilize head hair on the scalp. The body hair replenishes the donor area and also it theoretically primes the body hair for an existence on the scalp so that this body hair can later be moved to the top of the scalp and a new set of body hair grafts rotated into the donor area.
i want to re-emphasize that scarring has not been a major issue with FIT. We don't see much scarring. What i see is gaps where follicular units used to be. I have taken strips right through the heart of the donor area where FIT grafts were taken and i have seen no evidence of scarring. Hypopigmentation has occured in select instances, but the frequency appears much less with the application of anti-inflamatory products topically.
One must always bear in mind that FIT is the opposite of grafting. FIT is the gradual thinning of the donor area, while grafting is the gradual replenishment of the recipient area. Thinning the donor area creates contrast with areas that are thicker. As the surrouding areas are thinned in subsequent procedures, this contrast diminishes. the two areas become equal in density so the contrast is eliminated.
Contrast can be noted in the shaved recipeint area after the grafts grow in, as well. Trojan, for example placed photographs of his shaved recipeint area on his website prior to his second surgery. In my opinion, Trojan is a Norwood class early 3V or late 2V. Based on the apparent miniturization of his native follicles, i suspect he will ultimately advance toward a 4 or 5 Norwood class. These photos clearly show a difference in his natural follicualr density and the density in the grafts that were placed in the bare or thin areas. The density of his grafts appears to be about 30 per sq cm to me and even less on the hair line. the density of his original native follicular units of his recipient area appear to be about 100 to 115 per sq. cm. The obvious disparity in density from grafts to native follicular units creates noticiable contrast. This is the opposite contrast you see in the donor area where follicular units are removed one at a time with FIT. I typically reduce follicular density by about 25% in the first pass. With FIT as the density is gradually decreased in the donor area and gradually increased in the recipient area, contrasts are eliminated so that a full shave is possible if desired. Certainly very short hair styles eliminate these contrasts altogether and is a very suitable solution for lower hair transplant densities. Short hair styles make thin densities look good. The problem is that when you do strip surgery, it can be a problem for shorter hair styles because the strip scar can become apparent. This is not at all to suggest that FIT is the best solution in all cases. Clearly, there are many instances in which strip surgery is a good choice. I do not like strips at all in patients under 30 years of age. I like to leave their options open to them. They can always do a strip later on, but it is can be more complex to go backward from strip to FIT.
Body hair grows nicely in the donor area. It even grows quite well in donor area scars. i've seen one case where thigh hairs were 2 cm on the thigh, but over 4 cm long in the donor area with at least 90% yeild. Therefore, we are quite pleased thus far with body hair in the donor area. Still we recognize that this technology is new. It is not ready for every patient and it is not ready to market heavily to the hair transplant community. Patients need to go into body hair transplants with their eyes wide open and with a full understanding. we simply do not have enough cases under our belts to suggest that it will be completely successful in all patients. I must admit, however, that in over 2 years of performing body hair transplants, i have not seen any failures. Numbers are the critical element with body hair. we need higher densities to make up for the lower calcualted density. In other words, we are cautiously highly optimistic for body hair. It stands to reason that body hairs are hairs and that they will grow quite well on any scalp. It also stands to reason that if growth characteristics for head hair approach those of body hair when moved to the body, that body hair moved to the scalp should have altered growth characteristics more similar to head hair when moved to the scalp. This change takes time and is a primary rationale for moving body hair to the donor area at the same time you move head hair from the back of the scalp to the top of the scalp.
We have also begun to move body hair toward the front of the scalp based on outstanding results thus far with leg hair. We feel the leg hairs look very natural so we have moved foward with this strategy. we have taken advanced Norwood 6 cases with a depleted scalp donor area and given them a 6.5 cm hair line with a fuller look in the vertex, as well. we do not know what the final result will be in this instance, but it will be quite exciting to follow over the 12 to 15 months.
I fully recognize the critisims that exist with the work we are doing. Believe me, we are not new to critisim for our progressive modalities. Over 15 years ago, we were moving follicular units all over the scalp, doing cases in excess of 1500 grafts, and creating densities over 30 per sq. cm. Our colleagues told us it would not work. They told us that it would be too thin. Well, today, these same colleagues are doing what we did over 15 years ago and having the same sucess we had with it except that most did not jump on the band wagon until after 1998. Being a leader is not fun, it opens you to excessive critisism, but it is how we make improvements and push the envelope in the best interest of our patients. In Italy, i presented several cases of body hair transplantation to a group of physicians. Some of my collegues took me aside after the presentation and told me that my work was ridiculous and that it would never work. The next year, I presented the results from some of these cases to the same physicians. This time, their mouths droped.They have moved from disbelievers to believing that it will not work in all cases. One prominent physician even told me that perhaps I was the only physician who could do it. This simply is not the case. In due course, i predict that more and more physicians will employ this technology for their patients. It is simply our duty to continue educating them and then to give them the technique. I have 4 physicians in my office now. Each can do it. None could do it when they started with me. All they needed was a mentor and the right tools. Every day we devlop something new. We currently have over 32 different punchs with a variety of internal and external shapes, a variety of sharpness, a variety of steel hardness, and a variety of cutting edges along with a multitude of devices to use them with. The possiblities are infinite. I know what works best and when to use it. It is my next job to whittle these variations down to a more finite sum that is much easier to teach in theory and in practice.
John P. Cole, MD
John Cole su Hair Farming:
In my estimation, the average donor area has about 17,000 follicular units in its youth. I feel that many class 6 to 7 patients will have donor thinning over time. We see many individuals in their 50s who sought hair transplantation in their 20s, 30s, and 40s. They note a positive "coverage" result despite the often unnatural appearance of larger grafts done years ago. Many present not because they want to eliminate the unnatural larger grafts. Rather, they note a gradual thinning in the transplanted area over time. They also note a thinning in the donor area. In other words, the permanent zone is not always permanent. Body hair on the other hand does not tend to thin over time except in the sock zone of the lower legs. Body hair, on the other hand, increases over time. When hair tech began to work for me he had a perfectly naked chest and a full head of hair. He now has a few chest hairs of sizeable length and diameter in the periphery of his nipples.
The removal of 6000 follicular units from the donor area via FIT will not leave the donor area thin. Rather it leaves 1mm gaps that were once occupied by clusters of hairs. The fittest has large follicular bundles. We remove them intact and relocate them to his scalp. This leaves a tiny gap in the donor area. It is not something he has ever noticed. I do. It is my job to notice these things.
When I was young, I manicured many lawns in my neighborhood. Fall always brought down the leaves. I would clean gutters, sweep roofs, and rake leaves. The problem with raking leaves is that no matter how hard you try to get the yard or roof perfectly clean, Mother Nature is always working against you. A new leaf blows from one region to the area you just swept or out of your leaf pile, or might fall from the sky. If you care about the work you do, you might find this disturbing so you walk back the same area you just beautified, and pick up the leaf. The same preoccupation I had as a youngster to be a perfectionist in lawn care has carried over to my hair care. I find it just as disturbing today when I see a hair fall out or when I make a millimeter gap in the donor area.
The concept of hair farming is not new to us, but it is something we are beginning to employ. I thought of it about 3 years ago. I spent the interim perfecting the extraction methods. People ask me all the time, should I wait on a new break through in hair surgery before I begin. When I first began doing FIT, I recommended that patients wait before doing larger sessions. I felt we needed to perfect the extraction process. The problem was that people did not want to wait. We found ourselves knee deep in people wanting FIT simply because they did not want a strip surgery or because they were finished with strip surgery. We approached these cases with cautious optimism. We took each case on an individual basis and we treated each one in a customized approach as best we could. Over time we found different techniques that worked better on some individuals than on other individuals and some techniques that did not work on certain individuals. We had to come up with new approaches to some. The learning curve at the time was on perfecting the extraction process. We are now moving in a new direction and that is to perfect the overall FIT procedure. We will not cease our endeavors to improve. Should you wait on improvements? This is up to you, but many will not wait as I already pointed out. When we come up with something new and improved, however, we offer this to our patients who did not wait. We do not penalize them for wanting hair today. At this point, the improvements we feel will be minor, but there will be improvements and we hope there will be more major breakthroughs.
We just treated an area of about 250 sq. cm with a single pass of 10,800 grafts over a 6 day span (average 1800 per day). The donor density prior to surgery was 73 follicular units per sq. cm on the scalp. The donor density after surgery was 73 follicular units per sq. cm after the procedure. In other words, we took all the hair from the body. We will graft the frontal hairline and fill in gaps with scalp hair in 2 weeks. I expect to add an additional 1000 to 1500 grafts at that time. I feel that body hair has a lag time of about 15 to 24 months. The patient will keep his hair short so we will not be concerned with hair length. I do not recommend such cases at this time since this is cutting edge surgery that pushes the envelope, but I mention it because it will be a very interesting case to follow over the next 2 years. All the grafts to date have come from the chest, back, and abdomen. Very hairy men tend to have a higher percentage of anagen hairs and this was the case with this procedure.
I feel that strip scars are best grafted 12 months or later after surgery. Head hair into head scars is always my first preference. My second preference is body to head scars. Most strip scars will widen at the 3 month mark and continue to widen up to 6 months. There will not be much change between 6 to 12 months, but there could be slight changes. We have packed strip scars densely and gotten good growth, but it always makes me nervous because it is not native skin. Circulation in scars never seems to be a problem however. They bleed almost better than native skin when I stick a needle in them. I think that 30 to 40 per sq cm are acceptable in a strip scar, but you might want to keep the density to 20 per sq. cm. I leave this decision up to you.
If you are concerned with cost, I advise you to give us time or get on the standby list. I will train more physicians in due course. I prefer to train guys that I would allow to work on my family so it takes time to find the right people.
One of the primary reasons I do not feel that scarring is an issue with FIT is that I never see any scars, and rarely see hypopigmentation with body hair extractions. I've had patients come back that had absolutely no extraction marks. With surgery, one can never say never, however.
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John P. Cole, MD
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kursk2097.
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visto ke non capisco l'inglese, ki mi sa dire in parole povere ke densità c'è da aspettarsi, mediamente da un trapianto?
lo so ke dipende dal donor e dalla zona ricevente...intendo dire...con un folto donor fino a ke densità si può arrivare?
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Questo articolo è vecchio , le cose sono cambiate oggi?
Realisticamente i dense packing di oggi di solito a che cifre arrivano? Cole parla di 40-50 grafts , non ho capito se intende dense packing però. -
kabera.
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The analysis of hair density is depends on various factor like diameter of grafts, distance between two grafts etc. . -
Sareena.
User deleted
Thanks for the valuable knowledge .
HAIR TRANSPLANT DENSITY - DR. COLE |
