In Vivo Follicular Unit Multiplication: Is It Possible to Harvest an Unlimited Donor Supply?

Abstract

BACKGROUND Follicular unit extraction is a process of removing one follicular unit at a time from the donor region. The most important limitation of this surgical procedure is a high transection rate. OBJECTIVE In this clinical study, we have transplanted different parts of transected hair follicle by harvesting with the follicular unit extraction technique (FUE) in five male patients. MATERIALS AND METHODS In each patient, three boxes of 1 cm2 are marked at both donor and recipient sites. The proximal one-third, one-half, and two-thirds of 15 hair follicles are extracted from each defined box and transplanted in recipient boxes. The density is determined at 12 months after the procedure. RESULTS A mean of 3 (range, 2–4) of the proximal one-third, 4.4 (range, 2–6) of the proximal one-half, and 6.2 (range, 5–8) of the proximal two-thirds of the transplanted follicles were observed as fully grown after 1 year. At the donor site, the regrowth rate was a mean of 12.6 (range, 10–14) of the proximal one-third, 10.2 (range, 8–13) of the proximal one-half, and 8 (range, 7–12) of the proximal two-thirds, respectively. CONCLUSION The survival rate of the transected hair follicles is directly related to the level of transection. Even the transected parts, however, can survive at the recipient site; the growth rate is not satisfactory and they are thinner than the original follicles. We therefore recommend that the surgeon not transplant the sectioned parts and be careful with the patients whose transection rate is high during FUE procedures.