title: A comparative clinical and histologic study of hair transplantation using Er:YAG, Er:YAG/CO2, and standard punch techniques.
abstract: BACKGROUND
  This study compares the effects of Er:YAG laser alone, Er:YAG/CO2 laser at 5 W (low power), Er:YAG/CO2 at 10 W (high power), and standard punch techniques in 10 men with androgenetic alopecia.
  
  
  OBJECTIVE
  To study the clinical and histologic features of hair transplantation with recipient graft defects created by a new hybrid Er:YAG and CO2 laser.
  
  
  METHODS
  Ten male patients (mean age 34 y) with Norwood IV-VI androgenetic alopecia had hair replacement surgery with the recipient sites divided into four quadrants comparing cold stell, erbium, combined erbium low-power CO2, and combined erbium high-power CO2 technologies. Hair growth, intraoperative procedure, lateral thermal damage, and patient satisfaction were compared, utilizing each of the four stated technologies.
  
  
  RESULTS
  The addition of CO2 laser at both low and high power settings resulted in improved hemostasis when compared with standard punch or Er:YAG laser alone. The mean hair counts were similar for the Er:YAG laser, Er:YAG/CO2 (5 W) laser, and standard punch at both 3 and 6 months after treatment. Lateral thermal damage was not significantly increased by the addition of low-power CO2 to Er:YAG. The addition of high-power CO2 (10 W) laser resulted in slightly lower mean hair counts at 3 months, but significantly decreased at 6 months (P =.05). Also, high-power CO2 laser caused significantly increased lateral damage. There were no detectable differences in hsp70 expression among the groups.
  
  
  CONCLUSIONS
  The addition of 5 W CO2 laser to Er:YAG laser results in better hemostasis than Er:YAG laser alone, while not significantly diminishing mean hair counts or inducing increased lateral thermal damage.
authors.affiliation: Department of Dermatology, Weill Medical College of Cornell University, New York, New York, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Sadick
authors.forename: C R
authors.initials: CR
authors.lastname: Shea
authors.forename: J
authors.initials: J
authors.lastname: Nicholson
authors.forename: M
authors.initials: M
authors.lastname: Gat
authors.forename: S
authors.initials: S
authors.lastname: Lunievski
authors.forename: V G
authors.initials: VG
authors.lastname: Prieto
mesh_terms: D000328:Adult; D000505:Alopecia / Q000473:pathology / Q000601:surgery*; D005500:Follow-Up Studies; D006197:Hair / Q000637:transplantation*; D006801:Humans; D053685:Laser Therapy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000473:pathology; D012535:Scalp / Q000473:pathology / Q000601:surgery*