|John P. Cole, MD
||12-06-2010 04:54 PM
ACell, a Current Review of Applications in Hair Transplant Surgery
I’m issuing this response because I am beginning to get phone calls requesting treatment with plucked hairs that are tainted with ACell based on presentations by Dr. Jerry Cooley and Dr. Gary Hitzig along with irrational exuberance on the part of some physicians who incorrectly feel these presentations represent a clinical breakthrough in the treatment of hair loss.
My Use of ACell
I first looked at ACell in the spring of 2007. In June of 2007, I began to research it in terms of treating horses for their lacerations since I own several horses. Horses are somewhat hirsute critters sort of like mice. Mice seem to grow hair when you apply butter. While ACell can regrow hair in horse wounds, it may simply be their predisposition to hair growth in general that is a work. I waited until ACell became FDA approved prior to considering it for use in humans.
I will begin by relaying my experience with ACell and then discuss the presentations of Dr. Cooley. When I began using ACell, I really did not expect much other than improved donor extraction site healing. Obviously, I knew there was a potential for regeneration of extracted follicles, but since only the ectodermal stem cells would be residual in the donor area, I did not consider them to have a enough regenerative capacity by themselves. I started to apply it into extraction sites from FUE. The greatest challenge was how to deliver the product. The product originally came in two versions that were FDA approved for use in humans. One was a thin sheet and the other was a cluster of tiny particle that poses attractive electrostatic charge to one another and most any other object they come in contact with as described by Coulomb’s law.
More recently Acell offered a fine powder. The real challenge was how to get the small particles into extraction sites because the particles have a good bit of static electricity on them as previously described. This makes them somewhat sticky to the jeweler forceps, one another, hair, or anything else in the universe. Subsequently, I began cutting the thin sheets into small pieces and putting a small piece in as many extraction sites as possible. The greatest difficulty was noting which extraction sites had already been treated because you have to constantly look away to pick up another piece of ACell and it is often difficult to see the small pieces once you have placed them in the extraction sites. I’m quite sure that many sites were not treated as a result of this difficulty. Similarly, many sites were most likely treated more than once. Suffice it to say that I did the best I could given such a challenge. Later, I began mixing the small particles in a hyaluronic acid gel and forcing a small drop of the gel mixture to the extraction sites using a 1 cc syringe and an 18 or 19 gauge needle that I ground the sharp tipoff of.
When the fine powder became available, I switched to using this in the hyaluronic acid gel. The fine particles were a major breakthrough in terms of delivery. I found the ideal mixture was 60 mg of powder in 2 cc of the hyaluronic acid gel or 30 mg per cc of hyaluronic gel. One cc will usually treat well over 800 extraction sites. I often pre-treat the extraction sites with PRP and then drop the gel in to the extraction sites. Once again treating a non-shaven donor area with ACell particles is very difficult due to static electricity.
The particles want are attracted to the hair, as well as the jewelers forceps. The gel mixture facilitates the delivery of ACell to these tiny individual extraction sites. One question that remains is whether ACell will become active once the gel sets up and “hardens”. The premise is that the hyaluronic acid will be degraded and leave the ACell to do its job. Will the hyaluronic acid degrade fast enough for the ACell to be affective? I tried mixing the ACell in PRP, but it just clumped and was impossible to administer to my extraction sites. Thus, the optimal option to date is the Acell/hyaluronic gel suspension at this point. Currently, I am working on a superior suspension of Acell in hyaluronic acid, as well as a better delivery method.
I also began mixing 30 mg of the tiny particles in 30 cc of normal saline and injecting this into the recipient areas to include donor scars. I often treat these areas with PRP and microneedling, as well. I then activate the PRP by making incisions in the scalp or by injecting the patient’s thrombin or bovine thrombin into the recipient areas as taught by Joe Greco, PA, PhD. I have often added the ACell ECM to areas treated with PRP without grafts as Joe Greco has noted an improvement of pre-existing hair coverage in up to 70% of individual treated with a combination of ECM and PRP without grafting. I have noted the same in some of my patients, but follow up is difficult due to the distance between my clinic and the homes of my patients. Joe Greco has his own proprietary ECM that he obtains from the patient. Joe Greco has not released this ECM to other physicians yet. Joe is a wealth of knowledge and research with regard to PRP and eager to share this information.
I often add ACell particles to my grafts by placing 25 grafts at a time in a ring cup that we hold on our finger during placement of the grafts along with particles of Acell in the cup. This way the grafts are directly exposed to Acell and many pick up a few particles during storage in the ring cup due to attractive electrostatic forces. The hope is that such exposure and tainting will improve survival of transected hair and possibly improve the survival of the grafted hair in general. We have not seen any documented benefit of this procedure yet, but we are still evaluating it.
What I’ve noted so far is that ACell has the capacity to eliminate hypopigmented spotting in some FUE extraction sites. Those extraction sites that remained hypopigmented might not have responded or we might not have treated them with ACell. Again, it is impossible to know if all the sites are treated with ACell when you are using the powder or the cut up pieces of Acell. This is why I more recently began working with a gel because it is much easier to administer he gel suspension and it is far easier to verify that we have treated all the extraction sites. Acell also may have the ability to induce hair regrowth in some FUE extraction sites. I did not expect this to occur, but we were able to achieve some regeneration. For example, in a patient who had over 2000 grafts extracted, the number of hypopigmented spots were significantly fewer than the number of extractions, many extraction sites exhibited normal skin tone, and there were not as many empty extraction sites as one would expect following over 2000 extractions. In other words healing was better and some evidence of follicle regeneration was exhibited. Not all patients exhibit hypopigmentation with FUE, but those that do generally have hypopigmentation in all the extraction sites. The presence of both hypopigmented extraction sites and normal skin tone extraction sites suggests, but does not confirm, that Acell played a hand in improving the appearance of many extraction sites. Based on my experience in FUE, I also noted far fewer empty extraction sites than I would have expected following extraction of over 2000 grafts. This suggested, but did not confirm, that Acell may play a role in regeneration of hair follicles in extraction sites. I have also noted in other examples that an injection of a PRP and ACell combination can induce improvement in coverage of native hairs affected by androgenic alopecia in the absence of grafting. We also often treat these native areas with microneedeling and add thrombin to help activate the platelets in the PRP in areas of native hair that are not grafted. Again this practice has improved coverage in some, but we do not have statistically significant data to support our findings yet. A study in Korea showed that the PRP treated side resulted in faster graft growth than the untreated side of the grafted recipient area. Though I have not specifically evaluated this Korean finding, I have not seen confirmation of this Korean PRP study in my anecdotal evaluations.
As another example I had one patient who underwent a large session of body hair transplantation. He had excellent growth of his beard hair, but his chest hair did not grow well. In a follow up procedure, I treated his donor scars with chest hair, but this time injected the scars with ACell/Saline 1mg/cc and PRP. The chest hairs grew well this time and grew faster than areas treated with PRP alone with chest hair as well as beard hair. Did the Acell, PRP injections promote a better yield of body hair and did they promote faster regrowth of the body hair? This is yet another question that needs to be answered.
I have been slow to release my findings simply because it is too early and I do not want to stimulate irrational exuberance. We may not be able to confirm these findings though I feel very comfortable stating donor healing will be better with FUE extraction sites treated with Acell.
In summary, I have found the following, but I have not clinically confirmed them:
1. ACell plus PRP can induce improvement in coverage of native hair. Further evaluation is needed though Joe Greco’s findings combining PRP and an ECM are similar in terms of improved coverage.
2. ACell in the donor extraction sites can improve the healing of these extraction sites, reduce hypopigmentation, and induce follicle regeneration of follicles in extraction sites. This will require further evaluation and study. These are simply preliminary findings without scientific confirmation as yet.
3. I have not seen any benefit yet from treating grafts with ACell prior to implantation, but it may improve the survival rate of some grafts and some hair. This will need further evaluation.
4. A combination of ACell and PRP seems to help speed up body hair growth and improve body hair yield in some patients though this needs further evaluation and confirmation.
Despite these initial findings, it is too early to make any firm decisions regarding ACell with respect to FUE. While initial findings are impressive, we still need to discover a better deliver method to the extraction sites.
I remain highly skeptical of all this. Body hair has taught me to be careful with any predictions with regard to new treatment modalities. My single criticism of Dr Woods is that he practiced body hair transplantation for many years, but did not reveal that the results were not consistent. Such a revelation would have been important information to both physicians and patients. His failure to report this was negligent in my opinion. If he has a method, which I can not imagine, that results in consistent yields from body hair, then he has an obligation to present such a method. My first body hair transplants were a great success, but some follow up transplants resulted I poor yields and a poor coverage. Perhaps a combination of Acell and PRP will improve results, but it is too early to make any predictions based on a limited number of results. PRP alone does seem to speed the healing of body hair extraction sites including the beard, however.
I have no way at this point of determining if the ACell results are simply anecdotal findings. I need more patient follow up, which is difficult when most of your patients come from out of state. For this reason, I have been very cautious in my reports on ACell because I know all to well what can happen from irrational exuberance. All patients with limited donor areas want the Holy Grail. This is what body hair was supposed to be. It turned out that it was not.
A Review of Dr. Cooley’s Reports on Acell
I called Dr. Jerry Cooley in September to discuss his results and to relay my experience. I also published some of my findings in September on the Internet. Dr. Cooley was very helpful. My understanding from that conversation was that he noted the strip scars were not as wide when treated with ACell. Interestingly, he did not mention this in his published Internet presentations, but he did say that it made a good closure better presumably because the scar was softer and easier to excise in follow up strip procedures. He did state that ACell will not save a bad closure, but fails to note that the majority of strip scars are not ideal, fine lines. Rather they are usually 2 to 3 mm wide with a hairless gap. This is normal healing and ACell will not prevent or treat it based on his findings. The bad closures he refers to are simply bad technique. In other words, if you take out too much tissue such that you are forced to close under excessive tension, the scar will be wider than 5 mm in width. Scars up to 5 mm in width are completely normal and simply reflect the unpredictability of strip scars in terms of width even when closed properly by skilled physicians. He also relayed that they scars were more normal in consistency (softer) in punch scars and in strip scars. He did not discuss hair plucking with me during this phone call.
I did review Dr. Cooley’s abstract for Boston. I did not see any results in this manuscript. I then fastidiously reviewed what he has published on the Internet. I studied all his photographs and presentations carefully on both HTN and Bald Truth. I also considered his conclusions based on the results he presented. I would like to express my thoughts with regard to what he has published. First, I do not feel he has shown that plucked hairs grow better with ACell or without ACell. He has not shown that plucked hairs that result in growth in the recipient area also regrow in the donor area. It is impossible to show that the donor area heals better to feel and he has not shown that scars heal better in other regards due to ACell. He has not shown that transected hairs in a punch wound grow better with ACell. He has shown that plucked hairs do produce some yield, but we have known this since the Dr. Hitzig presentation in 2004 in New York. We have also known that plucked hairs don’t always grow and that this method of treatment was never popularized due to the inconsistencies in growth. He has shown that plucked hairs often result in a finer hair diameter even with ACell treatment. He has failed to provide conclusive evidence that grafts tainted with ACell result in more “robust” growth. I do feel he has some evidence that punch biopsy healing is better in the presence of ACell. In other words, I fail to see any reason for irrational exuberance at this time with regard to “autocloning” as there is no evidence what so a thing occurs or exists. Furthermore, the yields from plucking hair may indeed be worse than transplanting hair. We already know the hair is finer so where’s the benefit especially if there is less than 100% regrowth in the donor area and less than 100% yield in the recipient area?
If Dr. Cooley had wanted to show that plucked hairs treated with ACell resulted in better growth, he should have treated two boxes in a completely bald crown. One box should have contained ACell treated plucked hairs while the other box should have contained non-treated plucked hairs. He did not do this. What he did was treat plucked hairs with ACell and then implant them into hair bearing areas. The before photographs were over exposed with light, which makes the areas look more bald than they are. The after photos were less well exposed, which makes them appear to have more hair. This technique will always make the after photos appear to have more hair. In addition, because he chose to treat hairy scalps, one must be aware that that styling can make a difference. Therefore, I feel it is impossible to evaluate any of his plucked hair comparison photographs. This is not to suggest that there was no growth from the plucked hairs. Rather it is impossible to discern how much growth there was from the plucked hairs. Since Dr. Cooley did not perform a comparison study of ACell treated Vs. non-ACell treated plucked hairs, it is impossible to determine whether ACell had any effect on the growth of plucked hair. This is not to take away from the efforts of Dr. Cooley. Rather, I wish to attenuate the excitement of patients who are enticed by the unscientific findings of Dr. Cooley and Dr. Hitzig, whose presentations were directed primarily at the lay public. Furthermore, there are other physicians who have irrationally interpreted these results as a major scientific break through similar to cloning when in fact there is no scientific data to support such illogical interpretation by physicians.
Dr. Cooley stated that his initial study on plucked hair treated with ACell resulted in a 20% yield. As he became better at plucking hair, his yields increased. I surmise that he became more adept at plucking intact follicles. Intact follicles or nearly intact follicles are known to grow in the absence of ACell. In other words, he has only reported that he is able to improve survival of the plucked follicles through improved technique in plucking. He has not shown that improved plucking technique and ACell result in a better survival. Again, he did not evaluate the results of improved plucking with Acell tainting in comparison to improved plucking without Acell.
Dr. Cooley suggests that ACell will improve the survival of transected follicles. While I believe this is possible, transected follicles are known to survive in the absence of ACell. In other words, he has not proven that ACell will improve the survival of transected hairs. All he has shown is what we already know. Transected hairs are capable of regeneration. Whether ACell had any affect on this regeneration, we cannot predict, as he did not set up a study to evaluate the difference in survival rate for transected hair with and without ACell.
Dr. Cooley suggests that ACell can improve the appearance of strip scars. He has not proven this. He does state that strip scars are pink following treatment with ACell due to angiogenesis. Well, strip scars are always pink following surgery with or without ACell. Moreover, strip scars can stay pink or red indefinitely or permanently without ACell. Therefore, I don’t have any idea what he is alluding to when he mentions an association between a pink scar following treatment with ACell. Dr. Cooley states that the line of hypopigmentation persists following strip surgery treated with ACell. Therefore, the only benefit appears to be a softer feel to the strip scar. Well performed strip surgery in the absence of hypertrophic scarring does not result in a palpable or noticeable difference in the donor area. Hence, I have no idea what he is eluding to with regard to a better feel. In fact, I often have a difficult time finding my strip scars and certainly cannot feel a change in “feel” as I run my fingers through the vast majority of my strip scars. There is a way to quantitatively assess the hardness of scars treated with ACell, but all Dr. Cooley offers is a subjective assessment that I do not understand with regard to most of my patients. What he needs to do is a force comparison test measuring the Newtons of force required for a sharp instrument to penetrate both the Acell treated and the non-Acell treated scars and then statistically analyze the data. He did not do this. Dr. Cooley suggests that ACell can make a poor closure better, but presents no evidence to support this conclusion.
Dr. Cooley also states that strip scars tend to be wider with tight closures. Taking out a wider strip than the scalp allows does have a propensity toward wider scars. Never the less, patients with tight scalps and resulting tight closures based on their tight scalps tend to have the finest scars. In other words, as long as you do not over extend the width of your excision in a tight scalp, the scar will tend to be fine. Loose scalps on the other hand usually close with minimal tension yet such loose scalps are the ones most prone to a wide scar. This is a basic tenet to strip surgery. Acell should not have an overall impact on this biologic predisposition. The suggestion by Dr. Cooley to the lay public is that as long as the physician does not close with tension, a wide scar is not probable. Such a conclusion is inaccurate on his part as he implies that the width of a strip scar is dependent on physician technique and judgment. Loose scalps closed under minimal tension are the most prone to a wide strip scar. Tight scalps closed under acceptable tight tension are least prone to wide strip scars. Certainly, if a physician takes a 2 cm (almost one inch) wide strip when the donor area allows for only 1 cm due to the tightness of the scalp, the patient may form a wider strip scar. This would be poor physician judgement. Still a patient with a loose scalp may allow for a 2 cm wide excision that closes under minimal tension, yet the patient may form a wide strip scar. In other words, Dr. Cooley has not expressed all the factors involved in the width of strip scars to the lay public. Furthermore, Dr. Cooley did not discuss other parameters and their affect on the width of the strip scars in his presentation. For example, he did not discuss the tension of the scalp, the width of his excisions, the use of a double layer closure, or the use of a trichophtic closure. In essence, his lack of information makes his conclusions worthless to the medical community and misleading to the lay public.
Dr. Cooley states that ACell in FUE extraction sites improves the healing, but there is no regeneration of hair. In my experience ACell can improve the healing of a FUE extraction site, regenerate some follicles, and reduce hypopigmentation, but Dr. Cooley has not evaluated FUE extraction sites in his presentation. He has evaluated 4 and 5 mm punch biopsy sites, which are 4 or more times larger than an FUE extraction site. In a presentation on the Hair Transplant Network he has taken an approximate 4 mm punch biopsy from the scalp and states that the healing is better with ACell, but there is no regrowth of the hair. He goes on to state that this is a typical FUE extraction site. This is not true. No one I am aware of performs FUE with a 4 mm punch. Frankly, he should retract this statement because it is misleading to the audience it is directed to, the lay public. FUE has never caused the carnage that resulted from this 4 mm punch biopsy. In attributing such donor damage to FUE, Dr. Cooley’s assessment of the healing of a 4mm punch biopsy site could alarm patients considering FUE because an enormous hairless gap was created in the donor area. I think he should correct this statement immediately. How do we know this is a 4 mm punch? We can only assume, but the punch size is approximately equally to one half the diameter of the black circle. The black circle is a 0.5 sq cm reticule that fits on a dermlite. The radius or one half the diameter of this circle is 4 mm. Thus, the punch is approximately 4 mm in size. It is far less likely that ACell will regrow hair in a full thickness punch biopsy where all the stem cells, follicles, adipose, dermis, and epidermis are removed, just as it is far less likely that ACell can promote hair growth in a strip scar where a 1 cm or wider full thickness excision of all the stem cells, follicles, adipose, dermis, and epidermis occurs. In FUE, we are removing only the upper portion of the surrounding tissue. We are not performing a full thickness extraction. The inferior portion of the follicles is eased out. Thus stem cells are left behind. This is most likely why we see some evidence of regeneration of follicles in the donor area using ACell in FUE extraction sites. Furthermore, in FUE only a single follicular group is removed unlike the extraction of multiple follicular groups demonstrated by Dr. Cooley. When you ask Acell to do a little, it can. When you ask it to do more than it is capable of, Acell will not. You can regrow the tip of your thumb, but you are not going to regrow an arm amputated at the elbow with Acell. Similarly with Acell, you might regrow a single follicular group extracted with a 1 mm minimally invasive FUE punch technique such as I practice, but you are not likely to regrow multiple follicular groups extracted via a full thickness skin biopsy using a 4 mm punch that harvests up to 15 follicular groups collectively at one time.
Dr. Cooley has shown a reduction in the hypopigmentation that is characteristic with 4mm punch grafts or biopsies. He has demonstrated that Acell may improve the appearance in these biopsies. My findings suggest that Acell improves the healing of FUE extraction sites. Both Dr. Cooley’s 4 and 5 mm wide full thickness skin biopsies, as well as, my evaluations of FUE minimally invasive extraction site healing lack statistically significant data to support their findings. Never the less, they are corroborative findings in that hypopigmentation is reduced and the resulting scar is more normal in appearance. Both need more thorough study, however the cumulative data is positive.
Dr. Cooley also states that the plucked hairs are finer in diameter. In other words, they will not cover as well as transplanted hairs that are thicker in diameter. Plucked hairs will more resemble body hair in their potential coverage as body hair tends to be finer. The only reason to consider plucked hair is if it were to increase the potential donor area hair. Has Dr. Cooley shown that successfully plucked hairs that grow in the recipient area also grow back in the donor area? No, he has not. In fact his one example of donor regrowth was on one of his staff members, a female who wanted eyebrows. How many hairs did he pluck for an eyebrow hair transplant? I did not see many grafts in his example, but lets assume it required 200 hairs in total, as this appears reasonable given Dr. Cooley’s presentation. The growth was quite good though and I think it was the most impressive example of plucked hair growth that he presented. It still does not mean that Acell had any influence on the growth. The improved growth might have been due to improved plucking (intact scalp hairs are easier to pluck than intact beard hairs). Unfortunately, we still do not know if the growth was better due to improved plucking technique or treatment with ACell prior to insertion of the plucked hair. We do know that plucked hair will grow in the absence of ACell as Dr. Hitzig demonstrated as far back as 2000. In the donor comparison shots for this female, Dr. Cooley shows an area at the top of the right ear and behind it. The photograph is so over exposed that they woman’s hair appears blonde. The entire region appears to be void of hair. In the center of this circle of hairlessness, is a needle holder that obscures the view of the central plucked region. When I first examined this photograph, my assumption was that the patient would have been upset to have so much hair plucked because it left a large bald area. Closer evaluation shows that the area really looks fully plucked only due to overexposure by the camera settings (F stop and ISO) and lighting rather than due to plucking hair. The follow up photo shows a woman with brown hair (as opposed to blonde hair) because the photograph is not over exposed. The region in the donor area that is depicted is above the area that was plucked. The two areas are entirely different regions in the donor area. Yet, we are to believe that the hair that was plucked grew back. Suppose that you pluck 200 hairs to transplant to the eyebrows. Do you honestly think you could identify the identical 200 hairs you plucked a year later so that you could verify that they grew back? Absolutely not! In other words, Dr. Cooley has not demonstrated that successfully plucked hairs that grow finer in the recipient area have the capacity to also regrow in the donor area. In other words, there is no demonstrated benefit from plucking hair. You may only deplete your donor area in an effort to grow finer hair in the recipient area. The whole concept of autocloning is merely an aberration or a slight of hand based on photographic manipulation.
With regard to beard hair, I have evaluated Dr. Cooley’s photographs closely. Only a single hair in all his examples resembles a typical beard hair graft. The remaining examples have fine and straight hair. These are not typical for beard hairs and cause concern on my part as I have considerable experience grafting beard hair. Beard hair grafts tend to grow wavy and the hair is much coarser than scalp hair. If you put a beard hair graft beside a single scalp hair graft, you would see that beard hair is about twice the diameter of a scalp hair. Furthermore, the grafted beard hair wave or curl is quite distinguishable from finer straight grafted scalp hair even when the hair is wet. When I compare the beard hair side of Dr. Cooley’s photographs to his scalp hair side in the same patient, I do not see any difference in the quality of hair. As such I can conclude only three possibilities. One is that the beard hair he transplanted lacked the normal characteristics of scalp hair, which is unlikely as he presented several examples that lacked the typical appearance of beard hair. The second is that plucking results in a modification of beard hair such that it is finer and lacks the characteristic curl or wave. In this scenario the beard hair would produce less coverage than a typical beard hair graft. The final possibility is that the beard hair did not grow at all. Regardless of the possibility, it is clear that plucked beard hair does not cover as well as transplanted beard hair. Furthermore, there is no evidence that a plucked beard hair grows back at an acceptable yield. Dr. Cooley did present one patient with a bald vertex who grew a single beard hair. This would have been his best option to show that Acell had an impact on plucked hair survival. He also could have demonstrated the survival rate for both beard and scalp hair with and without Acell. Instead, all he did was biopsy the single beard hair that he depicted to show that a transplanted hair has a normal expected histological structure, which one would expect of any transplanted hair. It is a shame that he missed the opportunity to present more valuable information with this patient. One note for Dr. Cooley is that the non-growing beard hairs are foreign bodies. He needs to remove these as they will ultimately lead to cyst formation and can affect the yield of his transplant. These are dead hairs and need to be removed. There is no reason to wait for a growing hair to expel these dead hair, foreign bodies. These dead “whisker hairs” are potentially damaging to the transplant so Dr. Cooley needs to remove them as opposed to be intrigued by them.
Finally, Dr. Cooley suggests that grafts treated with ACell result in more “robust” growth. He presented two examples. One appeared to have no hair loss and the follow up photograph after one year simply presented a different styling option along with roots that needed bleaching. The second example was of a gentleman who got a result consistent with the number of grafts transplanted. The before photos were with wet hair. The after photos were with dry hair. The before photos had the hair styled back to conceal a balding crown and expose loss in the front. The after photos had the hair combed forward, which exposed a balding crown and made the front look thicker. The overall result was consistent with the number of grafts placed. Moreover, the patient entered into the procedure with a retained frontal hairline and a retained frontal forelock, which always make amy result look better than it would had he started with no pre-existing hair on the frontal hair line. There was also a consideral amount of pre-existing hair in the entire grafted area, which is additive to any hair transplant result. His follow up comparison showed nothing to suggest more “robust” growth of the grafts.
In final summary,
1. There is evidence that ACell improves FUE healing and full thickness 4 mm punch graft healing in terms of skin color.
2. There is evidence that ACell can regenerate hair in FUE extraction sites, but more work is necessary to insure this is not an isolated anecdotal occurrence.
3. There is no evidence that ACell improves the growth of plucked hair.
4. There is no evidence that ACell makes the growth of transplanted hair more “Robust”.
5. There is no evidence that ACell improves strip scar appearance.
6. There is qualitative evidence that ACell improves the feel of a strip scar in some instances, but it is difficult to understand how Dr. Cooley arrived at this conclusion .
7. There is no evidence that ACell induces transected hairs to regrow, but it might.
8. There is no evidence that plucked hairs regrow in the donor area, but they might.
9. There is evidence that plucked hairs will grow finer and result is poorer coverage than transplanted hair.
10. There is no evidence to conclude that “autocloning” occurs.
What Can We Expect from the Use of Acell with Plucked Hair?
There currently is irrational exuberance with regard to ACell. We need some real scientific data to support the benefits. In the interim, patients need to exercise caution with regard to plucking hair and the use of ACell. Such efforts may not result in more hair and may even jeopardize the potential coverage you can get by reducing the diameter of the hair shafts and reducing the regrowth of follicles in the donor area. IN OTHER WORDS YOU COULD BE IN WORSE SHAPE BECAUSE YOU UNDERWENT A PLUCKED HAIR SESSION OF “AUTOCLONING” USING ACELL. There are no studies yet to document the yield you can expect from plucking hair in the recipient area and no studies to show that it is safe to the hairs that are plucked from the donor area. Until Drs. Cooley and Hitzig can produce more scientific and statistically conclusive data, patients should proceed with caution with regard to plucking hair. My recommendation is that they avoid the plucking session with or without Acell altogether.
Now that I’ve discussed the scientific conclusions one may draw from the use of Acell, we should consider the limited probability that a successfully plucked hair will regrow in it’s donor region. Recall that Dr. Cooley stated his initial plucked hair success rate was only 20%. He noted an improvement in his yield as he improved his plucking skills. He also demonstrated the difference between a good plucked hair and a poor plucked hair. Essentially, a good plucked hair encompasses the entire follicle with the exception of 1/6th of the external internal (lower) portion of a follicle. The plucked hair is almost a completely intact follicle. What remain behind in the donor area are the lowest portion of the external root sheath, a very thin sheet of the internal root sheath adherent to the external root sheath, and the dermal papilla. At best only 1/6th of the entire follicle remains behind the donor area. With “autocloning” the nearly intact follicle is tainted with Acell. The residual tiny fragment of the follicle that remains in the donor area is not treated with anything other than nature’s magic wand. Why would anyone think that this tiny residual fragment of the follicle would result in nearly 100% regrowth? Perhaps if they treated the donor area with Acell, as well, we might see an improvement in the yield. Unfortunately, Dr. Cooley has already shown that plucked hairs that regrow in the recipient area are finer than transplanted hairs and finer than the original hair. The most important factor in terms of coverage is the diameter of the hair because diameter has an exponential affect on coverage. Consider that doubling the diameter of a hair quadruples the volume a hair provides at any length of growth. Halving the diameter reduces the volume to 1/4th of the donor hair. Doubling the number of hairs grafted simply doubles the volume of coverage. Thus, the last thing we want to do is reduce diameter except on in some instances on the hairline or specialty grafting such as the temple points because coverage is adversely affected in an exponential manner.
Now let’s turn our attention to the data with transected single hair grafts obtained by FUE and their growth in the recipient area, as well as their regrowth in the donor area. Suppose you transect a follicle at the lower 2/3 such that you transplant the upper 2/3 and leave the lower 1/3 in the donor area. The growth rate of the transplanted upper 2/3 without Acell would be 41.3% with a range of 33.3-53.3%. The growth rate of the lower 1/3 would be 53.3% with a range of 46.6-80%. In hair plucking you are removing more than 3/4ths of an intact follicle. You are leaving behind only the lower 1/6th of the ectodermal portion of the follicular sheath and the dermal papilla. In other words, you have at least a 41.3% chance of regrowth of the transplanted portion without Acell. With Acell tainting you might increase this yield, but the hair would grow in finer and may lack curl or wave. Transection at the lower 1/3rd will result in a yield of 53.3%. With plucking however, you are not leaving all the cellular components of the lower 1/3rd. Rather, you are leaving only the lower 1/6th of the external root sheath and the dermal papilla and you are not adding Acell to the donor area. In other words, you should have less than a 53.3% chance of regrowth of hair in the donor area. Why do I say less than a 53.3% probablility? Simply because survival of a single hair scalp follicle in the donor area decreases as you reduce the residual fraction of an amputated hair follicle, which is based on this same single hair transection study in FUE. If you leave a residual lower 2/3rds of the follicle in the donor area the survival rate is 84% (range 66.6-93.3%). If you leave the lower ½ of the follicle in the donor area, the survival rate of the lower ½ is 68% (range 53.3-86.6%). Again, if you leave the lower 1/3rd of the follicle in the donor area, the survival rate of the lower 1/3rd is only 53.3% (range 46.6-80%). With plucking you are leaving only the lower 1/6th of the external root sheath, a tiny layer of adherent internal root sheath, and the dermal papilla. This suggests that you might regrow a fraction of the plucked hairs (perhaps only 50% of the plucked hair) and what regrows in the recipient area will be finer. You also might regrow at best 50% of the donor hair and it might be finer too. Alternatively, in the donor area you might regrow far less of the hair that was plucked from the donor area. With beard hair, Dr. Cooley has suggested that the yield of plucked hair is less than with scalp hair and what grows is finer. We might assume from this finding that the yield of regrowth in the beard donor area is even less than the yield of scalp hair in the donor area.
Suppose you pluck 100 hairs, taint them with Acell, and transplant them to your totally bald recipient area. You could expect approximately 50 or more finer hairs to grow in the recipient area. You also might expect fewer than 50 finer hairs to regrow in the donor area where no Acell is applied. You very well could wind up with 50 finer hairs in the recipient area and 40 finer hairs in the donor area. Of course you very well could wind up with a much lower yield in the donor area as so little formative tissue remained in the donor area. In essence you might expect to have no more the same number of hairs as you started with (100) with ½ in the bald recipient area and less than ½ in the donor area. Unfortunately, you could expect that all remaining hairs would be finer. As such, you would be worse off than had you done nothing what so ever because the remaining hair would be finer. Since you might not even regrow 50% in the donor area in, you would be much worse off than had you practiced traditional FUE or strip surgery.
Beard hair obtained by FUE heals remarkably well with little evidence of extraction when proper technique is followed. Beard hair transplanted to the scalp from FUE has a mean survival rate of about 60% though higher and lower yields are possible. Therefore, you are more likely far better off to obtain beard hair from FUE than from plucking beard hair because the survival rate is acceptable and because the quality of the hair is far better than is possible from plucking. Of course tainting beard hair obtained by FUE with Acell and pre-treating the recipient area with PRP might improve the survival rate of beard hair. This is something that should be studied. In addition, the healing along with the potential for regeneration of the donor hair by adding Acell to the extraction sites seems to make this modality a far superior route.
The physicians who are enamored with plucked hair tainted with Acell are the same ones who have worried about the survival rate of “skeletonized” follicles obtained by FUE. What they fail to recognize is that there are minimal requirements for follicle growth. This includes an intact dermal sheath surrounding the follicle. FUE grafts are not skeletonized follicles. They are the components required to produce a hair follicle. Surrounding adipose that is present from strip surgery only adds to the volume of tissue that is extracted from the donor area and the volume of tissue implanted in the recipient area. This adipose adds nothing to the potential for follicle regrowth. With “autocloning” you are disassembling the follicle such that it not longer has the minimal requirements for growth and praying that Acell will make up the difference. What is left in the donor area is a mere fragment of the original follicle, yet these FUE skeptics feels this tiny residual fragment will routinely regrow hair in the donor area. Their conclusions defy logic. My suggestion for those considering “autocloning” is for them to proceed with caution at this point. I would not have more than 500 grafts placed in the initial procedure. Then you should evaluate the results both in terms of your expectations and those expectations of your physician twelve months later. Only if you are both happy with the results, should you enter into a follow-up procedure of “autoclonning”. My personal feeling is that “autoclonning” will result in unacceptable results, however. I hope I am incorrect in this assumption, but logic and experience dictate that my predictions are accurate.