Utilizing Donor Hair: FUE vs. FUT
A limitation of Follicular Unit Extraction (FUE) is the inability to effectively harvest donor hair. In FUE, only a portion of the best donor hair –- that which lies in the mid-portion of the permanent zone -– can be utilized for the hair transplant. In the FUE procedure, small open holes are left after the grafts are removed; therefore, a substantial amount of the donor hair in this area must be left behind in order to cover the resulting scars, or they will become visible.
In other words, if all of the hair were removed (harvested) from this area with FUE, the patient would be left with a relatively wide bald area at the back of one’s scalp. Since all the hair in this area can’t be removed, the surgeon must go above and below this permanent donor region to extract sufficient follicles for the hair transplant, but these regions contain hair that is often finer and subject to be lost over time due to the progression of the balding process.
In contrast, in Follicular Unit Transplantation (FUT), a single, long strip of hair is removed from the mid-portion of the donor area and all of this hair can be used for the transplant. The wound edges are then sewn or stapled closed leaving a single, generally fine scar.
Donor Sites in FUE vs. FUT
Open Donor Sites from FUE
Linear Scar in FUT
To explain it another way, the reason for the inefficiency of FUE in harvesting donor tissue is that with this technique, hair is extracted, but the intervening bald skin between the follicular units is not removed. If too much hair is removed, a greatly thinned or bald area will result in the donor region and the donor scars of the FUE may become visible. In contrast, with FUT, the bald scalp is removed along with the hair follicles. The remaining hair is redistributed in the donor area as the incision is sutured closed to leave a line scar covered with hair.
Consequently, there is considerably less total donor hair available with FUE, perhaps half as much as with FUT. This represents a significant disadvantage since a limited donor supply is the main factor that prevents a complete hair restoration in many patients. To compensate for the inability to harvest all the hair from the permanent zone, the surgeon may eventually be tempted to harvest hair from the upper and lower margins of the original donor area and risk the hair being of poor quality or being non-permanent.
Follicular Unit Extraction
In FUT, the strip is taken from the optimal (central) part of the donor region so all the hair in this area can be removed and transplanted. After the strip is removed, the wound edges are sewn or stapled together to form a single, line scar.
In Follicular Unit Extraction the wounds, although small, are left open to heal, leaving hundreds to thousands of tiny scars. Although not readily apparent, this scarring distorts adjacent follicular units and makes subsequent sessions more difficult. This is an additional factor that limits the total available donor supply in FUE. In FUT, the scarring is consolidated into one single line – even after multiple procedures, with the surrounding hair left intact.
Although new techniques and instrumentation significantly decrease the amount of transection and damage during the extraction process, the inability to fully access the mid-portion of the permanent zone in a hair transplant procedure, significantly limits the total amount of hair that can be accessed through FUE, rendering it a far less robust procedure than FUT for moderate to advanced balding.