5 Review of Studies on Graft Hair Survival

Michael L. Beehner and Ronald Shapiro

Summary

This chapter covers most of the important research studies concerning hair transplantation and related subjects. The importance of the International Society of Hair Restoration Surgery’s role in funding much of this research is cited. First, the studies showing the overall survival of the various sizes of grafts are presented. Next, the author features studies looking at the amount of protective tissue around the grafts and its relation to graft survival. A large number of small research groups compared the survival found with different planting densities. Grafts placed as far out as 2 and 4 days are presented in two studies, showing that graft survival starts to decrease after 8 hours out of body. Three studies looking at the angle at which the grafts are placed show superior survival with more perpendicular orientation to the scalp, but a better aesthetic appearance with the grafts at more acute angles. In a large 3-year study of grafts harvested by follicular unit extraction (FUE) and follicular unit transplantation (FUT; strip harvest with microscope dissection), the survival of FUE hairs/follicles was 70.1% and that of those harvested by FUT was 86.9%. Many hair surgeons are excited about the role of graft implanters and whether their use will increase the survival and predictability of FUE hair transplantation. A large number of investigators have performed studies on the effect of transections at various levels of the hair follicle. The results vary tremendously but give us some insight into what happens when partial follicles are left in the scalp. There certainly does not appear to be a “cloning” effect, in which two hairs are created from a single follicle.

Key words

hair transplant - graft survival - hair follicles - storage solutions - hair survival - density - follicular unit grafts - hydrogen peroxide

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