Density is the measurement of how many follicular units are placed in a cm²; the density of FU´s is one aspect but also on average how many hairs per FU are also being placed. A density of 70 FU cm² can mean anything from 70 hairs to 280 hairs if all the FU´s are 4 hair units.Placing at high density or dense packing as it is known has pros and cons. If a high density can be placed then the area covered can be treated in one pass with a natural thickness, but too high a density can impair the regrowth and skin healing.
The density required is largely determined by the hair characteristics of the individual, hair calibre, colour, number of hairs, and curl of the hair shaft. If a lower than required density is placed, even if a high yield is achieved the result will be of a diffused thinning appearance and not cosmetically appealing; needing a further procedure to increase the density in the same area, not ideal.
It is advised to achieve the correct density in one pass, although on higher hair loss stages when it is not possible to achieve total coverage it is sensible to reduce the density as the placement finishes and not leaving a flat hard and unnatural demarcation line; then this can be increased at a later date if desired, but a natural stand a lone result is achieved regardless.
Hattingen Hair Transplantation feels that the use of custom-made recipient site blades aids the creation of high density. Since each follicular unit is individual and varies in size, we use different blades and to create custom reception slits of varying width and depth to the follicular units. The width of the blade is very small, about 0.6-1 mm. Custom-made instruments also promote speedier healing in the recipient area, greater precision of placement, allowing for larger sessions to be performed and higher densities placed.
Poor density can also be due to poor graft management during the procedure, and impaired skin, scar tissue, pitting and ridging from a previous hair transplant procedure. Graft management, not to place transected or damaged follicular units as there is a high potential they will not survive the procedure resulting in a poor yield. That the overall procedure is performed efficiently so the follicular units are not out of the scalp for a prolonged time.
If the skin tissue is impaired, either by a previous poor hair transplant or into scar tissue this can reduce the growth rate, even when performed to a high standard. This should be explained prior to surgery to ensure the patient´s expectations are realistic.
The patient also has a responsibility to graft survival, the placed grafts are especially delicate in the first few weeks post operation and great care should be taken when washing and cleaning the scalp
When choosing a hair transplant specialist it is advised to ask what protocols the clinic has in place in case a poor yield or lower density than expected occurs