Scalp Surgery: Quantitative Analysis of Follicular Unit Growth

Background: Over the years, different kinds of hair transplantation have been compared in an attempt to overcome male pattern alopecia and, at the same time, maximize both the survival and growth rate of grafted hair. In this study, we have assessed the survival and growth rate of follicular units (FU) in an in vitro model, as compared with that of conventional hair micrografts, to experimentally evaluate and elaborate on the differences between these 2 approaches in hair transplantation procedures. Methods: Group A (control; n = 100 follicles) was composed of hair micrografts, whereas FUs were assigned to Group B (experimental; n = 100 follicles, n = 35 FUs). Each group was cultured for a period of 10 days; the total stretch of follicles was measured soon after the harvest and 10 days later. The Kruskal-Wallis one-way analysis of variance on ranks test was used to perform statistical analysis. Results: The growth rate of follicles from Group A (mean 10-day shaft growth rate = 0.30 mm) proved to be statistically different compared with that of Group B (mean 10-day shaft growth rate = 0.23 mm). Conversely, our data did not show any significant difference between the survival rate of hair grafts from these 2 groups. Conclusions: Our data highlighted a reduced FU shaft growth compared with that of hair micrografts, corroborating, to a certain extent, the hypothesis that a significant amount of adipose tissue surrounding the follicle included in the graft may result in an inadequate nourishment supply to follicular cells.