"Cloned" hairlines: the use of bisected hair follicles to create finer hairlines.

BACKGROUND: One living hair follicle, if horizontally bisected in the proper location, can be induced to subsequently produce two growing follicles. Their unpredictable growth rate, often less than 50%, has limited their use on a large scale. Their resultant finer caliber, however, can be used to benefit patients undergoing hair replacement surgery. OBJECTIVE: To determine whether horizontally bisected hairs can be employed to create finer, feathered anterior and temporal hairlines. METHODS: Twenty autologous terminal donor hairs were bisected as closely as possible to the "bulge" area immediately inferior to the zone of attachment of the arrector pili muscle. The 20 hair "shafts" were implanted along the left hairline. Twenty "bulbs" were implanted along the right hairline. Growth was evaluated and tabulated 2.5-8 months after transplant surgery. The procedure has been performed on 14 patients to date. Follow-up has been obtained on six patients ranging in age from 29 to 57 years. RESULTS: Overall, patients exhibited 46% growth from hair "shafts" (upper portion) and 47% growth from "bulbs" (lower portion). These bisected hairs were finer in caliber (diameter) than the original donor hairs. CONCLUSION: Horizontally bisected donor hairs can be implanted to create finer hairlines than otherwise would be expected from the theory of donor dominance. Further study is necessary in order to evaluate long-term success and additional applications of this technique.