Comparative Graft Survival Study of Follicular Unit Excision Grafts With or Without Minor Injury

BACKGROUND Various types of follicular trauma occur during follicular unit excision (FUE). However, the effects of different types of follicular injury on graft survival have not been reported. OBJECTIVE This study was performed to evaluate the differences in hair follicle survival by the type of follicular injury, including paring, fracture, and bulb injury. METHODS Seven healthy patients who underwent hair transplant surgery by FUE were enrolled in the study. For each patient, 10 single-hair follicular unit grafts per injury group (paring, fracture, bulb injury, or intact) were differentiated. Using sharp implanters, 10 grafts of each of the 4 injury types were transplanted into mice, and the mice were sacrificed 5 months after transplantation. The skin was excised at each of the 4 locations, and newly formed follicular units were counted and photographed under a microscope. RESULTS Of 70 hair follicles in each group, the number of successfully engrafted follicles was 50 (71.43%) in the intact group, 36 (51.43%) in the paring injury group, 9 (12.86%) in the fracture injury group, and 31 (44.29%) in the bulb injury group. CONCLUSION Grafts with minor injury had a lower survival rate than intact grafts. Fractured follicles showed the lowest survival rate.