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ACHIEVING DENSITY: Both Skill and Experience are Required to Produce Maximum Density

MAXIMIZING GRAFT SURVIVAL: Better Survival = Better Density

The evolution of tiny 1-4 hair follicular unit (FU) grafts was a breakthrough with respect to creating naturalness in hair transplantation. However FU grafts created new problems with respect to creating density. FU grafts are tiny and delicate and therefore susceptible to trauma and decreased survival. Cutting and placing large numbers of these delicate grafts very close together without trauma is technically difficult. There are many points throughout the procedure (i.e. donor harvesting, graft preparation, recipient site creation and placing) where the grafts are vulnerable to trauma and decreased survival. It is very important to overcome this vulnerability as there are only a limited number of donor hairs and each one is precious. SMG has been at the forefront of developing and using these modifications. Many modifications in techniques have been developed over the years to improve FU graft survival. A partial list of modifications is listed below:

  • High Power Surgical Loops and Microscopes are used at all phases of the procedure including when harvesting a donor strip and creating grafts, doing FUE extractions, making recipient sites, and placing grafts.
  • Specially developed FUE punches that limit trauma transection during the FUE extraction process. These are the COLE sharp punch and the HARRIS safe punch.
  • Specially developed FUE extraction Forceps that limits trauma when extracting FUE grafts.
  • Special Placing techniques such as the “Buddy technique” and “Stick and Place technique” which minimize trauma during the important placing step
  • The use of Hypothermasolan advanced holding solution that protect grafts from dehydration and PH changes while they are waiting to be implanted
  • The use of Custom Cut Micro Blades that perfectly match the size of grafts which makes placing the grafts much easier. These tiny blades also limit the amount of vascular trauma that occurs to the scalp
  • The Use of ACELL Matrix applied to grafts during placing to increase the survival of grafts.
  • The use of Liposomal ATP spray after surgery to supply oxygen and energy to grafts at their most vulnerable stage.

SMG has been instrumental in developing and lectured extensively on techniques that help maximize graft survival especially with dense packing and mega sessions (See CV). With the use of these innovations a skilled and experienced physician can achieve survival rates of above 90%.


As stated before, there is only a limited amount of donor hair available for transplantation and in most cases it is not enough to create, hair for hair, the same mathematical density (Hr/Cm2) that existed before hair loss started. As a consequence, a major challenge in hair restoration surgery is to create the best illusion of density possible at lower than normal pre-hair loss densities. To do this the donor hair has to be used as effectively as possible utilizing patterns, distributions, and techniques that create the greatest “appearance of fullness” with the least amount of hair. Stated another way, equivalent amounts of hair can appear thicker or thinner depending on how effectively the hair used to create the appearance of fullness. The ability to increase graft effectiveness is a skill that separates an average from an expert hair transplant surgeon. Knowledge of how to do this enables the physician to get the most out of a patient’s limited donor. Factors that influence graft effectiveness include:

  • Selective Distribution of different sized grafts to create the most effective patterns and distribution of hair
  • Graft Angle to create a shingling effect.
  • Graft Orientation which refers to the use of either sagaitall or coronal incision.
  • Hair Characteristics of color, curl and thickness

These are discussed in greater detail in their individual sections


Different size grafts vary in their ability to produce naturalness and density. FU graft range from 1-4 hairs. It should be obvious that 3-4 hair grafts are more powerful tools for producing density and should be used in the areas where high density is critical. By the same token 1 hair grafts are less effective for producing density but much better for producing naturalness and should be used in areas where undetectablity and softness is needed. Selective distribution is a very powerful tool that helps us concentrate density in the most important areas. Grafts need to be selectively separated during the cutting process so they can be selectively placed during the placing process… If grafts are not selectively separated the physician loses a very powerful tool.


  • graft1

    1 Hair Graft

  • graft2

    2 Hair Graft

  • graft3

    1 Hair Graft

1 Hair Grafts x 50 Grafts/Cm2 = 50 Hairs/Cm2
2 Hair Grafts x 50 Grafts/Cm2 = 50 Hairs/Cm2
3 Hair Grafts x 50 Grafts/Cm2 = 50 Hairs/Cm2


  • distribution1

    Selective Distribution

  • distribution2

    3 Hr. FU Denser Than 2 Hr. FU

GRAFT ORIENTATION: The effect of Coronal & Sagittal incisions

Hair can be placed (oriented) in either sagittal or coronal incisions. Each orientation has its own advantage and disadvantage depending on the situation and can be looked at as different tools in the surgeon’s toolbox. At SMG we use both types of incisions depending on the situation. With respect to density, coronal incision may increase the illusion of density by lining up hairs in the graft “side by side” instead of “one on top” of each other thereby creating more of a wall of hair between the scalp and the eye.This affect is particularly strong and useful when used with 3-4 hair grafts in the central area. On the other hand sagittal incisions have the advantage of being more precise when mimicking changes in direction. . Sagittal incisions are therefore a powerful tool for recreating cowlicks or changed in direction of the hairline. Neither of these rules is absolute and the decision of which orientation to use is based on these and a number of other considerations… At SMG we use both tools of coronal and sagittal incisions to take advantage of their relative advantages


  • Coronal Incisions


  • Sagittal Incisions



There may be a slight increase in the illusion of density when 3-4 hair grafts are used.
This difference disappears with 1-2 hair grafts

  • cag1
  • cag2

GRAFT ANGLE: The importance of the “Shingling” Effect

Hair naturally exits the scalp at an angle. It is important to follow this angle for a number of reasons. First the natural angle will create a more natural flow and look. Second following the natural angle when making incisions will limit transaction and damage to neighboring residual native hair. Preserving this hair adds to density. Finally proper angling will create a “shingling effect” that increases the effectiveness of hair at producing density. The shingling effect that occurs when hair is placed at a more acute angle positions the hair in a manner such that more of the surface area of the hair lies between scalp and the eye. It also causes the hair to overlap creating a greater illusion of density. In the past physician made the mistake of placing hair in a more perpendicular angle to the scalp. We now that the angle should exit the hair at an angle between 15 degree to 45 degree depending on the location in which the hair is being placed. In the central area the angle is typically somewhere between 30 and 45 degree which matches the angle of the pre-existing hair in this location In the hairline the hair is usually between 15-25 degree and in the temporal points or eyebrow area the hair is placed at very acute angle of 0 to 10 degree. Coronal incisions are a useful tools employed by SMG in areas where the hair has to be placed at the more acute angle less than 20 degree’s such as eyebrows and temporal points


  • Angle & Direction Changes Around Scalp


  • Proper Angle Prevents Damage to Native Hair


MEGASESSIONS: Large Graft Session

As techniques have improved so has our ability to transplant greater number of grafts in a single session. Today the size of a transplant session can range from as little as 100 grafts to as large as 4500 (or more). The appropriate session size for a patient is determined by many factors (i.e. patient goals, degree of hair loss, presence of pre-existing hair, donor density, scalp laxity, etc). There are some true benefits gained from larger sessions (faster results, less down time, etc) However there are also some increased risks as well (poor graft survival, increased donor scarring, increased length of surgery, etc). With appropriate patient selection and the proper technique the risks can be kept to a minimum. However, it is important to remember that patients are different and while some are good candidates for larger sessions others are better served with smaller sessions. At SMG we have the ability to do both large rand small sessions depending on the situation. We evaluate every patient individually and choose the most appropriate sessions size for that patient.

Below are examples of both a Mega Sessions consisting of 4400 grafts and a moderate case of consisting of 2300 grafts.


  • mega1


  • mega2

    Post -Op

  • mega3

    1 Year

Case 1 above is an example of a patient who fit the criteria for a megaession. consisting of 4400 FU grafts. This patient had a large area to cover, had good laxity in his donor area,very good donor density, and very little residual hair to injure and was not worried about cutting his hair short or a scar in the donor area.


  • mg1


  • mg2

    Post -Op

  • mg3

    1 Year

Case 2 is a more moderate size case of 2200 grafts. This approach was chosen because the patient only needed to cover the front third, had a tighter scalp with poorer density, was worried about a scar if he cut his hair short, and was about to start propecia which had the possibility of maintaining his crown.

These are examples of 2 different situations requiring 2 different approaches and both patients are very happy.

DENSE PACKING: Placing Grafts Close Together

Today grafts can be placed closer together than they could in the past. . Grafts may be placed at densities ranging from as low as 20 grafts/cm2 to as high as 50 grafts/cm2 or more. As with mega sessions placing grafts closer can increase the density created in a single session but also comes with some increased risk of poor growth. The literature shows that placing grafts at densities up to 30-35 grafts/cm2 will consistently produce survival rates of over 90%. Although successfully placing grafts at higher densities (40-50+ FU/Cm2) is possible, studies show that as the transplanted density increases beyond 40, the “potential” for poor survival also increases. With appropriate patient selection and proper technique this risk can be decreased but not eliminated. The optimum density at which to plant grafts are a subject of controversy in the field and an object of much debate. At SMG we have the skill and ability to dense pack if and when appropriate.

Below we show examples of both dense packing at about 50FU/cm2 and a more average density of about 35 FU/Cm2.

(1200-1500 FU’s in 30CM2 = 50/FU/CM2)

  • dense1


  • dense2

    Post -Op

  • dense3

    1 Year

Case 1 above case is an example of appropriate dense packing. The patient was older about 45, had good donor density, and had very full hair in the central area that did not appear to be at risk of progression. It this situation it was safe and appropriate to create a density in the hairline of about 40-50 FU/CM2

(3000 FU’s in the Front two thirds of the scalp (~100 CM) = 30 FU/CM2)

  • den1


  • den2

    Post -Op

  • den3

    1 Year Top

  • den4

    1 Year Front

Case 2 above is an example when dense packing is not appropriate and in fact not possible. The patient has fine hair with evidence he will progress to maybe type 6-7. His donor was poor, his laxity was tight. Because of this we were only able to get 3000 grafts in this session. To get more would have put him at a risk for a scar. The recipient area that needed to be addressed was the front 2/3 or about 120 CM2. If 3000 grafts were dense packed at 50/CM2 you would only cover 60 CM2, and this would barely cover the front third. Clearly it had to be distributed at a lower density. However the density of 30 which was created was good for him. He already had a density of about 10 with his native hair and the hope was that Propecia would add about another 5-10. This means that with the transplant and his native hair and the affect of Propecia he could be near the 50% mark which usually is enough to give an adequate appearance of density. This is what happened in his case and he was very pleased. If loses his native in the future or if the Propecia affect wears off he may drop his density back to 30 and at that time could have a second procedure to bump his density to 40 or 50 again. A final point to be made was that if he had better donor density and could have gotten more grafts (i.e. 5000 FU’s) he still would not have had dense packing. Some of the 5000 FU would have been placed a little further back in the crown. The total area would have increased to about 140 CM 2 and the average density would still be about 5000/140 =35 FU/ CM 2. The reason I am going into so much detail here is that there is a lot of chatter on the internet about dense packing and super dense packing that is not put into perspective. While it can be done like in Case 1, more typically a density of 30-35-40 is created in a single pass.


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