Treatment of burn hypertrophic scar with fractional ablative laser-assisted drug delivery can decrease levels of hyperpigmentation.

Abstract

Laser treatments have been used to treat a variety of scar symptoms, including the appearance of scars following burn injury. One such symptom is hyperpigmentation. There are several qualitative and quantitative measures of assessing improvement in hyperpigmentation over time. The Patient and Observer Scar Assessment Scale (POSAS) and Vancouver Scar Scale (VSS) are two scales that describe characteristics of scar such as pigmentation level. These scales are limited by their qualitative nature. On the other hand, spectrophotometers provide quantitative measures of pigmentation. Prior studies have reported that laser can change scar pigmentation, but no quantitative values have been reported. The current study examines changes in scar melanin index after CO2 fractional ablative laser scar revision (FLSR) via noninvasive probe measurement in patients of various Fitzpatrick skin types (FST). Patients with scars of various sizes and etiologies were treated with FLSR. A database was constructed including 189 patients undergoing laser treatment. From this pool, individuals were selected based on the criteria that they completed at least two laser sessions and had Melanin index measurements for both of these sessions and the pre-operative visit. This criteria resulted in 63 patients of various FST in the cohort. Melanin index, POSAS-Observer (O) and -Patient (P) pigmentation and color scores and VSS-pigmentation scores were examined over time. Demographic information (age of patient at time of first treatment, age of scar at time of first treatment, use of laser-assisted drug delivery (LADD), gender, FST, and Ethnicity) were collected from the medical record. Patients were grouped as "responder" if their Melanin index indicated decreased levels of hyperpigmentation after FLSR treatment in more than half of their total number of visits and "nonresponder" if it did not. The majority of patients were responders (41/63). In responder patients, measurements of Melanin index showed significantly improved levels of hyperpigmentation in hypertrophic scars after two FLSR sessions (p < 0.05). Age of patient, gender, FST, age of scar, ethnicity, or type of drug delivered by LADD did not predict responder grouping. POSAS-O and -P pigmentation/color scores showed improved scores after two FLSR sessions within the responder group. POSAS-P color scores showed improved scores after two and three FLSR sessions in the nonresponder group. VSS pigmentation scores showed improved scores after three FLSR sessions in the responder group only. Based on Melanin index values, FLSR leads to improvements in hyperpigmentation in certain patients.