The Science of Stretching Skin and Its Clinical Application

In the 1997 article by Dr. James E. Vogel, the science behind scalp stretching techniques for hair restoration surgery was explored. The article detailed the anatomical and biomechanical principles of skin expansion and advancement, including the viscoelastic properties of skin and the phenomena of creep and stress relaxation. It was noted that both biological and mechanical factors contribute to tissue expansion, with cellular proliferation accounting for 40% and tissue recruitment for 60% of the expanded skin. The article also discussed the use of skin stretching devices and techniques, such as Frechet's technique, to increase hair-bearing scalp area, although the cellular and histological mechanisms on collagen fibers were not fully documented. Traditional tissue expansion can double the scalp's surface area before thinning is noticeable, but it also thins hair density. The conclusion emphasized the importance of understanding the scientific basis of hair replacement techniques to ensure their safe application and to promote future advancements.