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Ablative Fractional CO₂ Laser Resurfacing for Acne Scars

This approach offers more benefits than nonablative laser treatment and fewer adverse effects than traditional ablative resurfacing.

Traditional ablative laser resurfacing can significantly improve acne scars, but with considerable downtime and a real risk for hypopigmentation and other adverse sequelae. Nonablative modalities achieve minimal-to-mild improvement of acne scars with minimal downtime and without serious complications. In this prospective study, 15 patients with moderate-to-severe acne scars underwent two to three full-face treatments at 1- to 2-month intervals with an ablative fractionated CO₂ laser. Patients were administered topical anesthesia with nerve blocks and oral oxycodone/acetaminophen and diazepam for pain control. Treatment energies ranged from 20 to 100 mJ per pulse, with total densities of 200 to 1200 microthermal zones per cm². Clinicians used higher energies for deeper scars and lower energies in areas without scars and on thin skin. Investigators and patients graded improvement on a quartile scale (0=no improvement; 4=75% improvement). In 10 patients, the depth of a preselected scar was measured before and 3 months after the last treatment using the Primos 3-D optical imaging system.

Both investigators and patients gave mean improvement scores in the 25% to 50% range for scar atrophy, texture, and overall improvement. The degree of improvement increased with each treatment and continued to increase between the 1-month and 3-month follow-up visits after the last treatment. Objective topographic assessment demonstrated a mean reduction in scar depth of 67%. The most severe acne scars that were treated with the highest energies achieved the best improvement (51%–75% at 3 months after last treatment). Mild-to-moderate erythema immediately after treatment decreased to trace levels by 1 month, and mild-to-moderate edema resolved to trace levels by 1 week. Transient petechiae developed in half the subjects. Oozing and crusting occurred in 80% of patients and resolved in all but two subjects within 7 days of treatment; in the remaining two, the oozing persisted for up to 1 month after the third treatment. Transient, trace hyperpigmentation developed in one subject, but none had scarring or hypopigmentation.