title: Treatment of acne scars with fractional CO2 laser at 1-month versus 3-month intervals: an intra-individual randomized controlled trial.
abstract: BACKGROUND
  Treatment of acne scars with ablative fractional CO2 laser appears to be an effective and well-tolerated treatment. However, so far the influence of treatment interval has not been evaluated.
  
  
  OBJECTIVE
  To evaluate whether treatment of acne scars with fractional CO2 laser resurfacing at 1-month interval achieves better results with no difference in the occurrence of adverse effects, than treatment given at 3-months interval.
  
  
  METHODS
  Patients (n = 13) with symmetrical atrophic acne scars on right and left sides of the mid-face and lower-face were randomized to two fractional CO2 laser treatments at 1-month versus 3-month intervals. Blinded on-site evaluations were performed 1 and 6 months after the last treatment on 10-point scales. Endpoints were scar atrophy, patient satisfaction, and adverse effects.
  
  
  RESULTS
  Pre-operatively, acne scars were moderately atrophic (5.86 ± 1.87). After treatment acne scars appeared with less atrophy on both treated sides 1 month postoperatively (1-month interval 1.96 ± 1.23, P < 0.0001; 3-months interval 1.82 ± 1.08, P = 0.0006) and 6 months postoperatively (1-month interval 1.56 ± 1.24, P = 0.0021; 3-months interval 1.33 ± 1.66, P = 0.0002). The treatment interval did not influence the improvement of scar atrophy at any time postoperatively (P = 0.81). Patients were moderately and equally satisfied with the treatment result on facial sides (P = 0.93). Postoperative adverse effects were minor and not influenced by the treatment interval.
  
  
  CONCLUSIONS
  Fractional CO2 laser resurfacing improves atrophic acne scars and a treatment interval of either 1-month or 3-months does not seem to influence the improvement of scar atrophy nor the occurrence of postoperative adverse effects.
authors.affiliation: Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Marie
authors.initials: M
authors.lastname: Bjørn
authors.forename: Birgitte
authors.initials: B
authors.lastname: Stausbøl-Grøn
authors.forename: Anne
authors.initials: A
authors.lastname: Braae Olesen
authors.forename: Lene
authors.initials: L
authors.lastname: Hedelund
mesh_terms: D000152:Acne Vulgaris / Q000150:complications*; D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000601:surgery; D002921:Cicatrix / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use*; D008875:Middle Aged; D017060:Patient Satisfaction; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: adverse effects; patient satisfaction; pigmentation; scar atrophy; skin redness