Greetings,
Today I will discuss an important concept in Hair Transplant Procedures known as “the illusion of density”. The typical density of follicles in a non balding scalp or healthy donor region is anywhere between 60-100 follicles per cm2. Usually the number is in the 70-85 range. Keep in mind that when I state follicles, the follicles may be single hair, 2 hair, 3, hair, or even 4 hair follicular units. Every individual has a different amount of each, but the average is about 2.5 hairs per follicle, with some having a slightly higher number and some slightly lower. The general rule is that once thinning of hair is noticeable in any particular region, the individual has already lost 50% of the original amount of hair that was present in the region. That is why we can create the illusion of density by re-creating slightly more than 50% of the original hair that was present in any given region. The reason why this is so important is that in many individuals they will go on to lose a large amount of hair over a lifetime. This can lead many male patients to end up as norwood 6 or 7, which means they end up losing most of the hair on the top of their head. The only difference between Norwood 6 and 7 is whether the donor hair fringe on the sides stays high, or gradually lowers over time as well. So clearly there would never be enough hair in the donor region to re create the original amount of density over such a large area. By meticulously and artistically placing the follicles with discrete angles and orientations, and creating a hairline that allows for future hair loss and conservation of donor follicles for this future loss, we can re- create completely natural hairlines, with less hair than was originally present. Hair caliber and curl are major determining factors in the final cosmetic result with an increase in hair caliber by .1mm possibly adding up to 30% to the overall cosmetic density of the final result. Also, skin to hair contrast has a major effect on the final cosmetic density as well.
This is why it is so important to have a strong grasp on the artistic elements that allow us to create this natural hairline and placing the hairline in a location that conserves donor hair for future hair loss.
All the best,
Marc Dauer, MD