If you observe the video below, you may see that density on the simulated scalp reduces as it is stretched. The more the scalp is stretched, the more the density is reduced. This rule can be applied to strip hair transplant (FUT) harvesting method because density is calculated based on quantity of follicular units over total area under consideration. After a reduction, the crown tends to move outwards and away from the central area of the scalp. The reduction may be applied to the crown itself. Both extremities of the incision tend to move outwards or away from the central area. Some ‘stretchback’ may help increase density on the scalp to a small degree. Tissue elasticity varies from patient to patient but reducing the scalp area inevitably reduces density. The total number of follicular units never increases after any reduction or harvesting and overall appearance of the scalp will be altered.
For physicians, the only benefit of reducing the scalp is that the length of the surgical procedure is considerably reduced. For the patient, the benefit is the reduction in expense for the procedure. The actual gain by the scalp reduction is usually partially or always lost after ‘stretchback’ occurs. This means the gain was time and money. The loss was the appearance which is gone forever.
Density = Follicular units/Area, therefore density decreases.