An analysis of follicular punches, mechanics, and dynamics in follicular unit extraction.

Success in follicular unit extraction requires an understanding of forces, fluid dynamics, instrumentation, and individual patient variation. Sharp punches require a lower axial and tangential force to dissect follicular groups. The angle of hair emergence and the size of a punch influence the wound size and the depth of an incision. A procedure must be individualized based on surface follicular group characteristics; hair splay; and strength of attachment between the outer root sheath, inner root sheath, and adipose with regard to hair follicles.