Dense Packing and Transection Rates

Dr. Rassman,

In regards to hair transplants, I believe that you’ve written that around 25% of the original density can be enough to provide coverage, and that as the graft density of a HT procedure increases (above 40%?) the transection rate goes up and one gets diminishing returns, etc.

So, I was wondering how this relates to “dense packing” of the frontal area — how dense can the grafts be when you do this?

Thank you for giving so much information and comfort to people in need of it.

Every patient is unique, and their goals and expectations will be variable. For those who want high density, “dense packing” it is attainable, but as you state there are issues of the diminishing returns observed by several doctors who reported growth findings in dense packing studies. I believe your concern for transection of neighboring hair in the recipient site is valid and it may contribute to this diminishing return phenomenon. However, surgeons who know what they are doing rarely will produce transection in adjacent hairs in a second or third procedure. Transection in the first procedure is never a problem unless we are talking about remnants of ‘original’ hair that is present (miniaturized or not).

Transection rates in strip surgery occurs on the edges of the excised strip and this is estimated to be no more than 5% in the hands of the average surgeon. For FUE, on the other hand, the transection rate ranges widely depending upon the surgeon’s skills. The FUE must be done by the surgeon (not assigned to a technician) by law in all 50 states. That means that the surgeon should have the skill to do this, but my experience from seeing the results of many FUE surgeries suggests significant failures in the hands of many doctors. Although the Artas® hair restoration robot is designed to minimize transection (keeping it under 10%), the studies so far have not followed the damage as those grafts are manually removed from the scalp and handled by the technicians when moved to the recipient site. Just keeping the grafts exposed to air for 20 seconds will kill them, even though there will be no evidence that damage has been done (other than the graft will never grow hair).

There is also a perception of how one sees the density when more than 25% of the original hair has been transplanted. For example, if the hair is fine, much higher densities are needed than if the hair was coarse. In normal thin haired individuals, the hair is often ‘see through’ in bight light with 100% of its original density. Obviously, in order to produce more fullness with medium weight hair, the weight of the hair alone is not adequate to determine the see through nature of the hair as it depends upon other things such as the character of the hair and the color contrast of the hair and skin. In adding an extra 100 grafts to an area with 1000 grafts, the change will barely be detectable, while adding 100 grafts to an area with 200 grafts will certainly look fuller (assuming that both areas have comparable surface areas). In the end, if you are willing to have multiple surgeries you can theoretically incrementally replicate the original density.

Now if your question is about dense packing an area with just one surgery, there is a limitation of how close you can place the grafts based on the needle or blade that is used to make the sites. It is a matter of graft survival, as the grafts may be handled differently for dense packing. Again, here the skills of the surgeon is paramount. There is also the doctor’s art in making the surgery result look dense with limiting the harvested grafts to keep costs down. I am sure most doctors can dense pack, but if you dense pack ALL the grafts, you may not likely be able to cover the planned treatment area especially if the bald area is high. For reference, a square inch of a non balding scalp in an average person is 1250 hairs (or 650 grafts) in an person with average density! So the trick is to utilize the number of grafts you harvest to dense pack certain KEY areas and spread it variably in other areas to make it look natural and full. This is where the artistic skill (not the technical skill) of the doctor comes in to play.

If you want a simple answer to how dense we can pack grafts, it is slightly wider than the needle/blade we use (some of which are sub-millimeter).