Survival rate according to grafted density of Korean one-hair follicular units with a hair transplant implanter: Experience with four patients

BACKGROUND: The survival rate of grafted hairs in hair transplantation has been frequently discussed by many hair-transplant surgeons. Several factors, including skill of doctors and assistants and the amount of perifollicular connective tissue, are suggested to have predictive values in foretelling the eventual quantity of hair growth. OBJECTIVE: The purpose of this study is to determine survival rate according to density of Korean one-hair follicular units grafted with a KNU implanter. METHODS: We designed four templates of 1 cm2 made by tattooing two templates on each side of empty frontoparietal recesses in four Korean patients with male pattern alopecia (beyond Norwood-Hamilton-Type IIIa). One-hair follicular units were prepared from occiput and we grafted 20, 30, 40, and 50 one-hair follicular units using a KNU implanter on each template, respectively, and counted the number of surviving hairs after 10 months. RESULTS: The survival rate of 20 and 30 grafts per template was higher than that of 40 and 50 grafts. CONCLUSION: We think that 30 one-hair follicular units grafted with a KNU implanter is the proper density for better survival in Korean hair transplantation, and repeated sessions will be necessary for a better final result. However, we need further evaluation with a larger number of participants to overcome the small sample size and limitation of one-hair follicular unit grafts.