To Dense Pack or Not to Dense Pack

What is dense packing?

For patients having a hair transplant, dense packing refers to the placement of hair follicle grafts close together such that the final density is high (i.e. dense) - greater than 30-35 follicular units per square cm.  Dense packing may lead to densities as high as 50 follicular units per square cm in some cases. The diagram on the right illustrates these different densities.

Some surgeons have argued that dense packing is preferable in some cases because a better cosmetic result can be achieved. Other surgeons have argued that very good results can still be achieved wtih densities of 30 -35 FU/cm2 without risking the chance of getting poor survival of the grafts.   Poor survival is a theoretical possibility because grafts have to be trimmed thinner and thinner in order to be able to pack them close together.

Over the past 5-10 years, we have slowly gained more information about the survival of grafts and particularly how to improve the survival of densely packed grafts. But certainly more research needs to be done. A 2005 study showed that graft survival with dense packing at 50 FU/cm2 was 84 % (i.e. 16 % died) compared to 98 % (only 2 % died) at a density of 30 FU/cm2.   Compare this to a 2008 study by Drs Nakatsui, Wong and Groot which showed that survival was as high as 98.6 % in  a patient transplanted with a density of 72 FU per cm squared in on small test area. The technique used to tranpslant hairs in this study was slightly different than used in the 2005 study mentioned above.

To dense pack or not to dense pack?

The decision on packing density depends on many factors - including their age, the quality of their hair (i.e. hair color, curl, coarseness), the available donor hair and the likelihood of future balding.

Dense packing of 50 FU/cm2 in a 45 year old man with coarse curly salt and peppery colored hair probably won't give much of a cosmetically different result than a 30 FU/cm2 density. In fact, doing so runs the risk of using up more hair and possibly limiting the number of hairs that might be possible to transplant when the man is 55 or 65.

The decision on dense packing needs careful consideration. 

References 

Mayer M, Keen se S, Perez-Meza D. Graft Density Production Curve with Dense Packing. International Society of Hair Restoration Surgery Annual Meeting. Sydney Australia 2005

Nakatsui et al. Survival of Densely Packed Follicular Unit Grafts Using the Lateral Slit Technique. Dermatol Surger 2008; 34: 1016-25.