Donor care is essential for performing hair restoration procedures and repairing bad hair transplants. It is true that many of the cosmetic defects caused by poor techniques can be partially or completely reversed by carefully removing and re-implanting unsightly grafts. However, the main factor that generally prevents surgeons from achieving all of the patient’s recovery goals is limited donor care. A depleted donor supply can be the result of hair loss from a bad hair transplant or the patient’s own genetic limitations.
Hair loss due to poor surgical techniques, as noted above, is usually the leading cause of donor burnout. The first telltale signs of hair loss can be a transplant that looks too thin for the number of grafts used, poor growth, which results in gaps at the hairline, or uneven density in areas where coverage is must be uniform. The wasted donor hair could be due to a donor cut longer than expected for a number of grafts, or an unusually low density in the donor area near the donor’s scar. Unfortunately, it is very difficult to retrospectively determine the exact underlying causes, and until the surgeon knows that there is a lack of usable donor hair, the patient is injured.
Because an adequate supply of donors is so important for a successful repair, an accurate assessment of the amount of hair available is of the utmost importance. When performing a hair transplant procedure on a virgin scalp, quantifying the care of the donor is quite easy as the density of the scalp and the laxity in the donor area is relatively uniform. However, additional factors play a role in repairs. Even though there appears to be enough hair in the donor area, it may not be surgically accessible. Factors that limit the available donor hair include:
Low donor density
Fine hair caliber
Poor scalp mobility
Scars
Low donor density –
Donor hair density (donor density) can be measured with a simple hand-held device called a densitometer. This tool is invaluable for assessing donor density, follicular unit composition and miniaturization. Patients with high hair density have more hair per follicular unit than follicular units that are closer together. The opposite is also true. A person with a naturally low hair density would have less hair per unit follicle but with the same distance between units (ie 1 unit follicle / mm²). This rule is less applicable at very low densities.
The scarring created by the traditional punch transplant method, in which the hair was harvested using the open donor technique, is a visible marker of the extent of operations performed. You can easily estimate the amount of donor hair used by comparing the area of open donor scars with the remaining virgin donor scalp. When harvesting the bands, however, the linear scar gives little information about the original size of the band, as it only reflects the length of the cut skin and not the width. With this method, the actual amount of tissue removed cannot be easily determined.
The percentage decrease in the density of funicular units gives an indication of how much tissue is being removed and, more importantly, how much remains to be harvested. In general, a person’s funicular unit density can be reduced to about 0.5 units / cm² before the donor area becomes too thin and the hair should no longer be harvested. Therefore, if the density of funicular units in the area of previous donor crops is 0.75 / mm, about half of the potential donor hair has been used and about half of the usable hair remains. In the example above, a 12.5% decrease in the density of funicular units means that 25% of the donor hair available in that area was used in the previous procedure.