title: Micro-island damage with a nonablative 1540-nm Er:Glass fractional laser device in human skin.
abstract: OBJECTIVE
  Fractional photothermolysis produces micro-islands of thermal injury to the skin while preserving areas among treated tissue sites in order to promote wound healing. Histological changes associated with single and multiple passes of the 1540-nm Er:Glass fractional laser were examined using in vivo human skin.
  
  
  METHODS
  Panni of five abdominoplasty patients were treated intraoperatively with a Fractional Lux1540 erbium glass laser system at various laser parameters, with single and multiple passes. Biopsies were removed and examined using standard histological stains.
  
  
  RESULTS
  Deep coagulated columns of collagen separated by regions of unaffected tissue were observed at variable fluence parameters. A direct correlation between the depth of penetration of the coagulated microcolumns and increasing energies was observed. Micro-islands of coagulation were approximately 250 microm in diameter and separated by approximately 800 microm of unaffected tissue. With multiple passes, significantly more disruption of the dermal-epidermal junction (DEJ) occurred at higher fluences. In contrast to the controlled fractional columns observed with single-pass treatments, nonuniform coagulated columns were distributed randomly throughout the tissue when instituting multiple passes over the same treatment region.
  
  
  CONCLUSIONS
  Micro-islands of thermal damage were observed at variable energy parameters. Pathological changes within the skin were clearly dependent on amount of energy and number of passes of the laser treatment. Significantly more superficial damage, accompanied by disruption of the DEJ was observed with multiple passes when compared with single pass at similar fluences. However, with multiple passes, depth of thermal injury did not increase with increasing energies but did disrupt the micro-island array observed with single-pass fractional treatments.
authors.affiliation: Department of Plastic Surgery, Clinical Center for Cosmetic Laser Treatment, University of Texas Southwestern Medical Center at Dallas, Dallas, USA. jordan.farkas@utsouthwestern.edu
authors.forename: Jordan P
authors.initials: JP
authors.lastname: Farkas
authors.forename: James A
authors.initials: JA
authors.lastname: Richardson
authors.forename: John
authors.initials: J
authors.lastname: Hoopman
authors.forename: Spencer A
authors.initials: SA
authors.lastname: Brown
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Kenkel
mesh_terms: D034861:Abdominal Wall / Q000473:pathology* / Q000601:surgery*; D001706:Biopsy; D019583:Dose Fractionation, Radiation; D004871:Erbium; D006801:Humans; D007430:Intraoperative Care; D028022:Low-Level Light Therapy / Q000009:adverse effects* / Q000379:methods*; D019651:Plastic Surgery Procedures / Q000379:methods; D012867:Skin / Q000473:pathology / Q000528:radiation effects*; D014945:Wound Healing; D014947:Wounds and Injuries / Q000532:radiotherapy*
chemical_list: D004871:Erbium