Analysis of Energy and Density in Treating Hypertrophic Scar After Burn in Children with CO2 Dot Matrix Laser

Objective: To analyze and compare the effect of the combination of energy and density parameters of CO2 dot matrix laser in the hyperplastic stage of pediatric burn. Materials and Methods: A total of 160 pediatric patients with hypertrophic scar after limb burn from 2017 to 2020 were randomly divided into four parameter groups (n = 40). The patients were treated with ablative fraction carbon dioxide laser, once every 10 weeks. During the interval of laser treatment, Compound Heparin Sodium and Allantoin Gel (Contractubex) was applied externally, tid, and elastic cover or elastic bandage is attached to the affected limb. Scoring based on the Vancouver Scar Scale is performed before each laser treatment, The score before the first treatment was the initial score, which was scored by two people separately, and the average score was calculated. Subsequently, the patients were treated four times and scored. The differences between each treatment and the first score of each parameter group were compared. Under the same energy and different treatment density, the scores after each treatment were compared. Under the same density and different energy, the scores after each treatment were compared. The bleeding and pigmentation of each parameter group were compared. Results: The increase of density can show the therapeutic effect earlier than the increase of energy, and 25mj energy and 10% density have better intervention effect. With the course of disease and the progress of treatment, the correlation between intervention effect and parameters tends to weaken. Comparing the number of cases with different scores between each treatment and the first time, the score in the 5% density group was lower than that in the 10% density group, but there was no significant difference between the 25mj and 17.5mj energy levels in the same density group. The intervention effect of the increase of density on scar was better than that of energy, and the increase of energy and density could aggravate the pain. Conclusion: In pediatric burn hypertrophic scars treated by CO2 dot matrix laser in exfoliation mode, the intervention effect of increasing density is better than that of energy. When setting laser treatment parameters, we should give priority to increasing density and adjust energy according to the effect of treatment and the condition of pain, bleeding and color precipitation. In this study, the best combination of parameters is 17.5mj/10%.