Graft Rate Survival Redux

[redkun9]

Hey everyone,

 

I'm curious about the current consensus regarding graft rate survival for strip procedures. By this, I mean the survival rate of implanted grafts, as opposed to the harvest yield (survival of grafts excised from the donor area). I feel this is immensely important for this community in that it has a direct bearing on one's aesthetic results and expectations. If you implant at 40 FU/cm2, but only achieve 90% survival, you're only getting 36 FU/cm2. Does that mean you should aim for an implanted density higher than 40 FU/cm2 to achieve an actual density of 40 FU/cm2? To answer this question requires an appreciation of the difference between implanted and achieved density, and how that difference may change at higher densities. For example, does implanting at higher densities reduce graft survival? I've read in several posts that this is probably the case, but I'd like to know what evidence supports this probabilistic assessment and how much do survival rates drop at higher densities? Doing a few searches, I've uncovered informative discussions that I'll be referencing below. To all the doctors out there, I'd love to hear your thoughts and any updated research studies that have been released.

 

In 2005, Dr. Beehner discussed how FU graft surival "has varied all over the board...mostly averaging around 90% survival" while also noting that implanting into virgin scalp has better survival rates than subsequent sessions.

 

In a set of posts during 2008 (which I strongly suggest you read for yourself), Dr. Beehner writes, "In two recent studies I conducted, the follicles contained within 2-hair FU's survived in the mid 90% range, whereas 1-hair FU's survived between 65-75%. The 2-hair FU's were placed in 19g needle sites and the 1-hair FU's into 20g sites." He suspects that "the lack of protection and physical buffering around a skinny 1-hair FU makes it far more vulnerable to both trauma and drying". He also notes that these studies have been performed in conditions that are more likely ideal and in areas that don't have to share blood supply with thousands of other implanted grafts. He writes, to my lament, that "no one as yet has studied growth of FU's in the midst of such dense, large sessions" (large sessions referring to 3,000 - 7,000 FU grafts).

 

There is also an interesting conversation between Jotronic and Dr. Carman in 2008 about the survival rate of grafts above 40 grafts/cm2. Dr. Carman writes, "It has been demonstrated that a density of 40grafts per square cm will give near 100% graft survival, all other things being equal. It has also been observed that when grafting at higher densities than this, the survival rates of the grafts decreases. So, while it may be technically possible to make and place 60 grafts per square cm, the survival rate is in the low 90-93% range." Dr. Carman makes an interesting point about the relationship between the number of insertion sites into an area and the implanted graft's hair count in terms of density. Jotronic argues that these studies aren't methodologically rigorous and also weren't performed by individuals who necessarily have the experience of dense packing or megasessions. He claims the studies "cannot simply be thought of, executed, then have the data be considered valid if the proper experience to perform the studies to begin with is absent".

 

I've tried to summarize these posts to revive discussion about these issues, and any misrepresentation of the author's opinions is my fault alone. Likewise, I strongly suggest you read these posts yourself.

 

My particular comments are: has a consensus been established within the Coalition doctors about the estimated survival rate of grafts at various density levels? For example, what should the expected graft survival rate be for a Coalition doctor at 40 FU/cm2? 50 FU/cm2? 60 FU/cm2?

 

What are the results of any new research? Given that this is the terrain of hair transplant surgeons, their comments would be particularly salient.

 

Cheers

[redkun9]

Hey everyone,

 

I'm curious about the current consensus regarding graft rate survival for strip procedures. By this, I mean the survival rate of implanted grafts, as opposed to the harvest yield (survival of grafts excised from the donor area). I feel this is immensely important for this community in that it has a direct bearing on one's aesthetic results and expectations. If you implant at 40 FU/cm2, but only achieve 90% survival, you're only getting 36 FU/cm2. Does that mean you should aim for an implanted density higher than 40 FU/cm2 to achieve an actual density of 40 FU/cm2? To answer this question requires an appreciation of the difference between implanted and achieved density, and how that difference may change at higher densities. For example, does implanting at higher densities reduce graft survival? I've read in several posts that this is probably the case, but I'd like to know what evidence supports this probabilistic assessment and how much do survival rates drop at higher densities? Doing a few searches, I've uncovered informative discussions that I'll be referencing below. To all the doctors out there, I'd love to hear your thoughts and any updated research studies that have been released.

 

In 2005, Dr. Beehner discussed how FU graft surival "has varied all over the board...mostly averaging around 90% survival" while also noting that implanting into virgin scalp has better survival rates than subsequent sessions.

 

In a set of posts during 2008 (which I strongly suggest you read for yourself), Dr. Beehner writes, "In two recent studies I conducted, the follicles contained within 2-hair FU's survived in the mid 90% range, whereas 1-hair FU's survived between 65-75%. The 2-hair FU's were placed in 19g needle sites and the 1-hair FU's into 20g sites." He suspects that "the lack of protection and physical buffering around a skinny 1-hair FU makes it far more vulnerable to both trauma and drying". He also notes that these studies have been performed in conditions that are more likely ideal and in areas that don't have to share blood supply with thousands of other implanted grafts. He writes, to my lament, that "no one as yet has studied growth of FU's in the midst of such dense, large sessions" (large sessions referring to 3,000 - 7,000 FU grafts).

 

There is also an interesting conversation between Jotronic and Dr. Carman in 2008 about the survival rate of grafts above 40 grafts/cm2. Dr. Carman writes, "It has been demonstrated that a density of 40grafts per square cm will give near 100% graft survival, all other things being equal. It has also been observed that when grafting at higher densities than this, the survival rates of the grafts decreases. So, while it may be technically possible to make and place 60 grafts per square cm, the survival rate is in the low 90-93% range." Dr. Carman makes an interesting point about the relationship between the number of insertion sites into an area and the implanted graft's hair count in terms of density. Jotronic argues that these studies aren't methodologically rigorous and also weren't performed by individuals who necessarily have the experience of dense packing or megasessions. He claims the studies "cannot simply be thought of, executed, then have the data be considered valid if the proper experience to perform the studies to begin with is absent".

 

I've tried to summarize these posts to revive discussion about these issues, and any misrepresentation of the author's opinions is my fault alone. Likewise, I strongly suggest you read these posts yourself.

 

My particular comments are: has a consensus been established within the Coalition doctors about the estimated survival rate of grafts at various density levels? For example, what should the expected graft survival rate be for a Coalition doctor at 40 FU/cm2? 50 FU/cm2? 60 FU/cm2?

 

What are the results of any new research? Given that this is the terrain of hair transplant surgeons, their comments would be particularly salient.

 

Cheers

[Maxxy]

Hey Redkun9,

 

What an excellent post!!

 

Thank you for taking the time to ask the questions you have, and posting your research - I will be following this thread closely.

 

I would also like to know if any guys have had their grafts counted after they have fully grown out? If so - how many grafts were placed per cm2 during the transplant and what was the count when fully grown?

 

It would also be good to know of the above numbers, how many were 1,2,3 and 4 hair FUs? However, I realise that these numbers are very unlikely to be known, in the fully grown cases.

[Bill - Seemiller]

redkun9,

 

I agree with Maxxy that this is an excellent post.

 

The problem is that the topic of graft survival rate at higher densities is still heavily debated amongst leading physicians. The general consensus has been, more study is required.

 

Personally, I believe as grafts are being trimmed even smaller and transplanted into tinier incisions, that higher densities are possible without sacrificing growth yield. But exactly what density can be achieved without sacrificing growth yield definitely requires more study.

 

Thanks for the reminder of this very important topic.

 

For more information, see "Dense Packing Complications" in the Highlights of the Annual 2008 ISHRS Conference in Montreal.

 

Best wishes,

 

Bill

[mmhce]

redkun9,

 

Bill and Maxxy are both right!

 

This is an excellent post! and I have followed such threads with interest, and will follow this one with similar keen interest!

 

I had read the threads you had quoted previously, and initiated my own thread, Keys causes on non-growth of transplanted grafts

found here:

 

http://hair-restoration-info.c...321027304#3321027304

 

where I solicited such responses, but at that time didn't know the survival rate of grafts were 90% at best and below, nor had I thought about the quoted 45 FU/cm2 to provide the illusion of density should take into consideration the survival rates of the transplanted grafts, when I initiated the thread, Guaranteed Density by Surgeons, which is found here: http://hair-restoration-info.c...04?r=4351088#4351088

 

Good Post and good question!

 

I hope some of the illustrious doctors respond to this post.

 

take care,...

[Dr. Michael Beehner]

I was asked to update my comments from what I said before about hair follicle survival in high densities, but for the most part would pretty much say the same thing now in late 2008.

There was a nice study published in the journal, Dermatologic Surgery, by Dr. Tom Nakatsui and Dr. Jerry Wong about a year ago or so, in which they used small lateral slits and created study boxes of between 23 and 72 slits per square cm of surface area, and obtained a 95.6% survival in the 23/cm2 box and 98.6% in the 72/cm2 box. These results are outstanding, although we have to keep in mind that the study was done on ONE patient and the same results may or may not occur with another person. Also, as I recall, these boxes were around the periphery of the area transplanted and I don't believe any were actually in the center, which I would think would be the area most at risk for possible less-than-ideal growth. I have noticed in past studies I have conducted that, even though I did everything exactly the same, I often would see marked variation in hair follicle survival a year out. Every hair surgeon that I have spoken with acknowledges that there is an individual patient "X factor" that we can't totally put our finger on, but does in fact exist.

There are a number of factors that I think definitely play a role in worsening the survival of densely packed grafts: Among these are: cigarette smoking; a very thin scalp with little subcutaneous tissue; a scalp that has had a lot of past surgery performed on it;

Another factor that I think makes a huge difference in a hair surgeon's ability to create density and obtain good growth at the same time is the SIZE OF THE RECIPIENT SITE. There is no question that the custom-made lateral slits allow us to place a larger number of recipient sites in a given square area than ever before. Then the limiting factor becomes the safety with which the placers can insert the grafts without traumatizing them. With extremely dense sites, this is much more difficult with the hair left long.

I will again make the statement that I believe the biggest factor in getting good dense growth is not necessarily the density with which the sites are made, but rather the skill and conscientiousness of the assistants who are placing the grafts. If they do their work in a rough, slipshod manner, there is going to be terrible growth. If they are gentle and meticulous with each placement, then the growth will probably be wonderful.

I haven't gotten around to doing any further survival studies on 1-hair FU's but would welcome others doing so, to see how they compare. The 3-4 studies I have performed comparing 1-hair grafts with 2-hair grafts would suggest that there is 10-15% less growth with the 1-hair grafts. This is simply a function of their slim build and inherent vulnerability to dessication (drying) and trauma with handling.

Mike Beehner, M.D.

[Dr. William Lindsey]

I was asked to comment on this thread. First, the start of the thread is an excellent post. Second, Dr. Beener gives excellent insight and years of expertise in his response.

 

Third...and pending funding...one of my residents and I are hoping to conduct an animal model study showing vascularization of hair grafts. I hypothesize that plasmatic imbibition, similar to what is seen in skin grafts, occurs with follicular units.

 

As to the diminished survival of singles...I would say that we don't see this clinically. That is either because we are taking extra precautions to cool, not freeze, and quickly place singles.

 

If indeed plasmatic imbibition is the process going on, singles should be as hardy if not hardier than doubles.

 

Time will tell when we can get this underway.

 

Dr. Lindsey McLean VA

[Dr. Timothy Carman]

I have been asked to revisit a comment I made in a previous thread, an excerpt from which is quoted above. I would like to point out that, in the context of the question in that thread, I was talking in broad generalities in an effort to set up a conceptual background against which my answer to the poster's question regarding the rationale of using larger grafts could be appreciated or better understood. In the context of the above question raised by redkun9 I can offer my opinion as follows. As Dr. Beehner points out, there are a number of factors which affect survival rates at given densities; not the least of which, I whole-heartedly agree, is the skill and care with which the grafts are created, handled, and placed by the surgical technicians. I continue to maintain that, as Dr Beehner points out, the size of the recipient site is critical, so much so that in our practice I have evolved to the use of custom made blades tailored to the individual patient on a per case basis. Moreover, as the hair restoration procedure itself is a 'team' procedure, the individual practice should have a good idea of the general density parameters of which it is capable and which work the best in general across 'all' comers. Again, as pointed out, that 'study' above quoting the 98% survival rate at 72 FU/cm2 was done on ONE patient- it would be less than prudent, in my opinion, to generalize this result to all patients in all circumstances.

Rather, it would seem to me to be in our patients' best interest to limit recipient densities to an upper limit that, in the given surgeon's practice experience, would yield as close to 100% survival rates as possible in the vast majority of all patients undergoing a given procedure, than to pack at a higher density at the risk that any single patient might not get the benefit of growth of nearly all of the precious grafts transplanted from his or her donor area.

And, just for the sake of completeness, I would like to offer the following; density is but one of a number of parameters a surgeon must utilize in the creation of a natural appearing result. Just as critical are the variance of densities, gradation of transitions from one density to another, the skillful and appropriate use of different graft sizes, as well as the manipulation of radial angles and the angle of elevation of the recipient sites, to name but a few. Density is an important concept, yet it is critical, in my opinion, to appreciate that it is but one slice among many in the hair transplant procedure pie.

Thanks for the opportunity to respond.

Sincerely,

[mmhce]

Thank you all for your comments!

[Dr. Michael Beehner]

One other comment on graft survival that I forgot to include is the orientation of the slit in the recipient site. Dr. Wong deserves credit for showing us that excellent density can be achieved with the "perpendicular" (erroneously referred to as "coronal" by some) orientation of the site, and I agree with him as long as the size of the site is relatively small. I do feel strongly that there is some critical "divide" or threshhold of recipient site size, past which one has to switch to a "parallel" orientation ("sagital") in order to not embarass the vascular support to the grafts and risk necrosis in a central area. I'm not totally sure where that cross-over point is, but my guess is that the 0.6, 0.7, and 0.8mm sites are fine when made perpendicular, and I think the 0.9's are probably ok too, especially if confined to the deep hairline area only. But, I think once you get to 1.0mm and wider, that it is wise to stay with the parallel orientation.

There is a mixed blessing with this orientation:As Victor Hasson points out in the Haber/Stough textbook, the opening of the site will actually be a tiny bit wider than the actual 1.0mm size of the blade which makes it easier for entry placement of the graft, especially the 3-hair and 4-hair FU's. The down side is that, because the opening is that little bit larger, not as many sites can be placed in 1cm2 of area as with the perpendicular sites. I will try and attach a drawing from the text which shows this:

Mike Beehner, M.D.

[Dr. Michael Beehner]

Here's the other drawing, showing the effect on the size of the opening of the site using perp or parallel orientation.

Mike Beehner, M.D.

[mmhce]

Thank you all doctors for your comments, but somehow I believe the initial question was not answered:

 

Does that mean you should aim for an implanted density higher than 40 FU/cm2 to achieve an actual density of 40 FU/cm2?

 

If you all still follow this thread can you comment this please.

 

Thanks.

[Bill - Seemiller]

mmhce,

 

40 FU/cm2 should be obtainable without risking hair growth yield. I believe higher densities can too with today's smaller tools.

 

In my opinion, a hair transplant should yield as little waste as possible. Therefore, if it's suspected that transplanting too high of a density would compromise some growth, a surgeon should perform two sessions to acheive the desired density to maximize use of the available donor supply.

 

Best wishes,

 

Bill

[mmhce]

Therefore, if it's suspected that transplanting too high of a density would compromise some growth, a surgeon should perform two sessions to acheive the desired density to maximize use of the available donor supply.

 

I was just thinking the same thing this morning, but still asked the question. Imagine that!!!

[lorenzo]

They is alot more differences in doctors that many may not know. Even if two experienced doctors put the same amount of grafts, lets say lateral slits, in the same area with the same density, the outcome can still be different.

Although this discussion is very knowledgable and interesting in my opinion a doctor study is relavant to himself and don't believe it can be 100% relavent to other doctors. I have been hearing for years that large session were not possible high density were not possible and yes the doctor saying this was probaly correct in his own practice and for other doctors its incorrect.

There is alot of difference even if the doctor performs the same procedure. These are some of the differences in my opinion.

1) virgin scalp vs previous surgery.

2) how the strip is taken out (any damage to the grafts)

3) Lateral slits vs needles. Even if two doctors both use lateral slits some doctors with not that much experience have damaged the recipent area by either by making the slits too deep or not deep enough.

4)staff; this is very important as many experience doctors know it take many years of experience to feel confident about your staff.

5)what happens to the strip once it is removed.

6)how the grafts are cut

7)how many staff members you have working. Very important because when fatigue sets in so does error.

8)equipment used and products used

9)doctors experience and ethics.

This are some of the difference in my opinion. There is alot of things that can influence grafts survival. Large studies performed by many doctors with alot of patients would be better at answering these questions. Doctors experience is based on his own experiences and usually so they may have alot or little revervance to other doctors. In my opinion no two doctors are the same. Some of the world leaders in years past are now dinosaurs now because they refuse to look past there own experiences. If you could look back 10-15 years ago, many of the top doctors then are rarely mentioned now.

[lorenzo]

Therefore, if it's suspected that transplanting too high of a density would compromise some growth, a surgeon should perform two sessions to acheive the desired density to maximize use of the available donor supply.

 

Bill your first two transplants amount were almost the same of your third one. Do you believe that you recieved a higher density from the first two transplants or the third. I don't mean final density I mean density from each procedure. You mentioned in another post you if you could go back in time you would have recieved a bigger session at the beginning if this is how you feel then I am a bit confused with the about comments. Please do not take this the wrong way no disrespect intented. .

Since you have alot of knowledge and experience, lets say right now you have never recieved a hair transplant. How many grafts with a guessed flexablity do you think you could recieved now? What kind of density do you think you were able to achieve in your first transplant in the hairline?

Thank you and happy holidays.