Achieving appropriate densities in hair transplantation

The density of follicular units can be calculated by dividing the number of grafts placed in an area by the area. This patient with extensive thinning was transplanted at a density of 32 follicular units per square cm (32 FU/cm2).

What densities do we aim for in hair transplantation?

One of the most important parts of the hair transplant surgery is determining how close to place or 'pack' the grafts. A patient with a large area of hair loss to fill (such as a Norwood VI) with limited donor supply may want to use 3000  grafts at a density of 30-35 follicular units per square cm. Another individual with limited hair loss in the frontal scalp may want to use 1000 plus hairs packed at a density of 35-45 follicular units per square cm

 

 

Different follicular unit densities for different patients and different areas of the scalp

The frontal hairline is an area where decisions on target density are very important. A density of 40-45 follicular units per square cm was planned for this patient.

The density that is chosen for each patient requires careful thought. A patient with course curly grey-white hair will require less grafts for than a patient with fine straight blonde hair. A density of 30-35 FU/cm2 might be chosen for the grey haired patient whereas a target of 40 FU/cm2 or more may be required for the patient with fine hair.

In addition, different areas of the scalp often require different densities to achieve a good result. The frontal hairline might require 40 FU/cm2 to 50 FU/cm2 depending on the patient.

It's extremely important to think about the density of recipient sites in hair transplant surgery There is not magic formula or recipe - and each patient's procedure needs to be carefully considered and planned.