title: The efficacy and safety of subcision using CO2gas combined with fractional laser for acne scars: Clinical and microscopic evaluation.
abstract: BACKGROUND
  Various modalities have been used to treat acne scars. CO2fractional laser is an effective and commonly used treatment. CO2gas injection into the dermis by needle with high pressure can cause fibrotic collagen breakage, producing the effects of subcision. CO2also stimulates collagen synthesis by increasing neovascularization and releasing oxygen.
  
  
  OBJECTIVE
  This study evaluated the efficacy and the safety of the combined treatment with CO2gas subcision and CO2fractional laser for acne scars.
  
  
  METHODS
  Fourteen patients with acne scars were treated with three sessions of CO2gas subcision at 2-week intervals and two sessions of fractional laser at 4-week interval. The clinical improvement was assessed using a 4-point scale. For histologic analysis, punch biopsy was performed before and after treatment in 10 patients.
  
  
  RESULTS
  All patients experienced clinical improvements. Excellent, marked, moderate, and mild response was achieved in 1 (7%), 8 (57%), 4 (29%), and 1 patient (7%), respectively. Histologic evaluation of the biopsy specimens showed increased dermal collagen with dermal thickening and elastic fiber straightening in the reticular dermis after the treatment.
  
  
  CONCLUSIONS
  The combination therapy with CO2gas subcision and fractional laser was satisfactory and safe for treating acne scars. Abbreviation and acronym: CO2: Carbon dioxide GAS: Global assessment scale H&E: hematoxylin and eosin; SD: standard deviation.
authors.affiliation: a Arumdaun Nara Dermatologic Clinic , Seoul , Korea.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: a Arumdaun Nara Dermatologic Clinic , Seoul , Korea.
authors.forename: Dong Hye
authors.initials: DH
authors.lastname: Suh
authors.affiliation: a Arumdaun Nara Dermatologic Clinic , Seoul , Korea.
authors.forename: Ka Yeon
authors.initials: KY
authors.lastname: Chang
authors.affiliation: a Arumdaun Nara Dermatologic Clinic , Seoul , Korea.
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: b Department of Dermatology , School of Medicine, Kyung Hee University , Seoul , Korea.
authors.forename: Tae In
authors.initials: TI
authors.lastname: Kim
authors.affiliation: b Department of Dermatology , School of Medicine, Kyung Hee University , Seoul , Korea.
authors.forename: Ki-Heon
authors.initials: KH
authors.lastname: Jeong
authors.affiliation: b Department of Dermatology , School of Medicine, Kyung Hee University , Seoul , Korea.
authors.forename: Min Kyung
authors.initials: MK
authors.lastname: Shin
authors.affiliation: c Department of Pathology , School of Medicine, Chung Ang University , Seoul , Korea.
authors.forename: Kye Yong
authors.initials: KY
authors.lastname: Song
mesh_terms: D000152:Acne Vulgaris / Q000532:radiotherapy*; D044466:Asian People; D002921:Cicatrix / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D016896:Treatment Outcome
keywords: Acne scars; CO2; fractional laser; subcision