Various Types of Minor Trauma to Hair Follicles During Follicular Unit Extraction for Hair Transplantation

BACKGROUND: When performing follicular unit extraction (FUE), various types of minor hair follicle trauma unapparent during follicular unit strip surgery are likely to occur. However, no studies have examined such damage. METHODS: In total, 100 grafts were randomly selected from each of 42 patients who underwent FUE with a 1-mm-diameter sharp punch. A ×5.5 magnifying loupe and a ×60 magnifying binocular microscope were used. The transection rate (TR), paring, fractures of and damage to the dermal papilla (DP) areas, and hair bulb partial injury were assessed. RESULTS: Observation with the magnifying loupe revealed an average TR of 7.40%, and 4.31, 1.90, 1.52, and 0.43 hair follicles per 100 grafts exhibited paring, fracture, DP partial injury, and hair bulb partial injury, respectively. An average of 9.21 telogen hairs were observed. Microscopic examination revealed a TR of 6.34%, and 9.07, 1.95, 0.79, and 1.24 hair follicles per 100 grafts exhibited paring, fracture, DP injury, and hair bulb partial injury, respectively. An average of 16.62 telogen hairs were observed. CONCLUSIONS: Various types of minor hair follicle damage occur during FUE as shown by loupe and microscopic examination of the grafts. Especially paring and hair bulb injury were more apparent under microscopic examination. These minor hair follicle injuries should be considered when choosing operative method or surgical techniques.