title: Hidden Transection of Follicular Unit Extraction in Donor Site.
abstract: BACKGROUND
  When calculating the transection rate in follicular unit extraction (FUE), many surgeons did not consider damages that may arise in the donor site through FUE punching.
  
  
  OBJECTIVE
  The authors investigated what changes and/or damages are happened to the hair follicles surrounding a punched hole.
  
  
  METHODS
  Two to 4 study boxes were marked on the donor strip and 8 follicular units were harvested using FUE from each study box. Follicular unit extraction was performed by the expert for 10 patients and by the beginner for 10 patients. After the strip harvesting, each study box was separated. Then, the 2 cross sections along the punched line and follicular units obtained from each study box were analyzed under a 20-power digital microscope.
  
  
  RESULTS
  The authors found various transections through this analysis. Among them, some transections were hidden under the scalp surface, keeping the shaft alignment. The authors named this occurrence "hidden transection." Although 2 surgeons harvested with similar transection rate, there was a significant difference in hidden transection rate: 2% for the expert and 8% for the beginner.
  
  
  CONCLUSIONS
  The main finding of this study is that a correct way to calculate the real-transection rate in FUE is to consider both extracted follicular transection and hidden transection.
authors.affiliation: *Department of Plastic Surgery, Apgujeong Yonsei Hair Transplantation Center, Seoul, Korea; †JP Plastic Surgery Clinic, Seoul, Korea; ‡YES Plastic Surgery Clinic, Seoul, Korea.
authors.forename: Dae-Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Jong-Pil
authors.initials: JP
authors.lastname: Choi
authors.forename: Young-Joong
authors.initials: YJ
authors.lastname: Hwang
authors.forename: Hyung-Suk
authors.initials: HS
authors.lastname: Kim
mesh_terms: D018859:Hair Follicle / Q000293:injuries / Q000601:surgery* / Q000637:transplantation; D006801:Humans; D008866:Microsurgery; D020858:Tissue and Organ Harvesting / Q000009:adverse effects / Q000379:methods*; D060053:Transplant Donor Site