When hair-bearing tissue is withdrawn from one area of the scalp for transplantation to an area that is hairless due to male-pattern hair loss (MPHL), the withdrawal is made from the donor site-an area unaffected by the genetics of MPHL. The donor site in the balding male is hair-bearing scalp tissue that runs from an inch or two above the ears and temples to the back of the head. This donor area might be called the savings-and-loan area: hair follicles in this area are saved from the effects of MPHL and are available for loan by transplantation to scalp areas that have lost hair due to MPHL. Transplanted hair follicles from the donor site retain their resistance to MPHL genes and continue to produce hair at the recipient site.
In planning a hair transplantation procedure, the physician hair restoration specialist will pay as much attention to the donor site as to the recipient site. Accurate assessment and effective use of hair-bearing tissue at the donor site are important factors in the eventual success of hair transplantation in any individual patient.
The potential “Permanent” donor zone as determined by an examination of hair density in the donor area in 328 randomly chosen men aged 65 years or older. Note that it is 69mm high in the midline of the occipital area and that hair with fewer than 8 hairs per 4mm circle is present superior, inferior, and anterior to the shaded “safe” donor area. (From unger W, ed, hair Transplantation, 3rd ed, New York: Marcel Dekker, 1995.)
Although the donor area exists in all male patients, it is not precisely the same and can vary considerably from patient to patient. The physician hair restoration specialist will want to identify the “safe” hair-bearing donor tissue that will permanently retain its resistance to MPHL genetic control. Making this identification requires careful evaluation by the means of the patient’s family history of hair loss and by scalp examination. Hair-bearing tissue that, at casual examination, may seem to be within the general area of a prospective donor site may eventually be lost to MPHL over succeeding months to years. Careful evaluation significantly reduces the possibility that the hair-bearing tissue chosen may eventually be lost to MPHL.
Careful evaluation of Donor area includes:
Evaluation of the prospective donor area by family hair-loss history and scalp examination provides information vital for planning the hair transplantation procedure. However, assessing the amount of hair-bearing tissue to be used for transplantation is considered in context with other important factors:
When MPHL hair loss is substantial and donor area is limited, hair restoration planning may also include a surgical procedure such as scalp reduction (Click on Surgical Treatments for information about scalp reduction) that will reduce the area of scalp that requires transplantation. The pros and cons of this procedure should be discussed with the physician hair restoration specialist. Assessment of the donor area for hair-bearing tissue to use in transplantation also includes assessment of hair characteristics:
Walter Unger, MD, one of the “fathers” of modern hair transplantation, has observed that no donor hair characteristic is better than any other for achieving the optimum outcome for the individual patient. The best outcome is the one that achieves the wishes of the patient and the professional satisfaction of the physician hair restoration specialist.
Techniques for harvesting donor tissue have improved steadily over the years. Newer techniques may improve hair yield as much as 50% to 100% over older techniques. Newer techniques generally result in less donor-site scarring as compared to older techniques. The patient should ask for a description and explanation of donor-site harvesting as part of full preoperative discussion with the physician hair restoration specialist. Understanding of how the donor site is to be used is as important to the patient as understanding how donor tissue is to be used in the recipient site.