To evaluate the clinical efficacy of recombinant human epidermal growth factor gel combined with CO₂ fractional laser in the treatment of hypertrophic scars after burns and traumatic.

Twenty patients with hypertrophic scar who were admitted to the Department of Burns and Wound Repair Surgery, First Affiliated Hospital of Anhui Medical University from December 2020 to October 2021 were selected and divided into the combined treatment group and the laser treatment group according to the random number table method, with 10 cases in each group. Before operation, the operation area of patients in both groups were taken photos, disinfected, wiped dry, and evenly applied 5% compound lidocaine cream locally, then a sterile film was sealed and protected for 60 min, and the cream was wiped off, the operation area was disinfected again. During the operation, the CO₂ fractional laser therapy device was used to scan the patients′ scar, and the appropriate machine parameters according to the thickness of the patients′ hypertrophic scar were selected. The machine frequency was maintained at 300 Hz and the density of 5%, adjusted the energy parameter at 20-30 J, the interval was 1 sec, and ensure that the hypertrophic scar was covered by the lattice rectangle completely, allowing a 25% area overlap between the thermal damage matrix formed by the two lasers. The wounds were cold compressed for 60 min after operation. Within 1 week after operation, the laser treatment group was not given any external medicine, and the combined treatment group was given external application of recombinant human epidermal growth factor gel 3 times a day in the operation area. For 3 days after the operation, the treated area should not touch water. If there was infection, antibiotic ointment should be added to the surgical area. If the scab outside the wound was not completely removed, the wound should not be scrubbed, the scab should not be directly peeled off, cosmetics should not be applied to the operation area, and avoided direct sunlight. The second laser treatment was performed 2 months after the first laser treatment, and two CO₂ fractional laser treatments were taken as a course of treatment. At 2 months after 1 course of treatment, the curative effect was judged when the operation area was stable, and the total effective rate of the two groups of patients was calculated. According to the Vancouver scar scale (VSS) and the patient and observer scar assessment scale (POSAS), the patients′ scars were scored before treatment, 2 months after the end of the first laser treatment, and 2 months after the end of the second laser treatment. Data were compared with repeated measures analysis of variance and chi-square test.

(1) Two months after one course of treatment, the total effective rates of the patients in the laser treatment group and the combined treatment group were 80% (8/10) and 90% (9/10), there was no statistically significant difference between the two groups (χ²=2.40, P=0.49). (2) The indexes of VSS scores between the two groups were compared and there were no statistically significant differences in pain, itching, softness and thickness scores within and between groups at each time point (P>0.05). Before treatment, 2 months after the first laser treatment and 2 months after the second laser treatment, the color scores in the VSS score of the laser treatment group were (1.9±0.7), (1.9±0.1), (1.8±1.0) points, respectively, and were (2.9±0.7), (2.8±0.6), (1.9±0.7) points in the combined treatment group. The two groups were compared at different time points, and the difference was statistically significant (F=26.143, P<0.05); there was statistically significant difference between the two groups at different time points (F=6.753, P=0.018). Before treatment, 2 months after the first laser treatment and 2 months after the second laser treatment, the blood vessel distribution scores in the VSS score of the laser treatment group were (1.8±1.0), (1.7±0.7), (1.5±1.0) points, respectively, and were (2.6±0.5), (2.5±0.5), (1.7±0.8) points in the combined treatment group. The two groups were compared at different time points, and the difference was statistically significant (F=17.603, P<0.05), and the difference between the two groups at different time points was not statistically significant (F=2.538, P= 0.129). (3) The indexes of POSAS scores between the two groups were compared, and there were no statistically significant differences in the thickness, roughness, softness and surface area scores within and between groups at each time point (P>0.05). Before treatment, 2 months after the first laser treatment and 2 months after the second laser treatment, the color scores in the POSAS score of the laser treatment group were (4.9±2.6), (4.1±0.8), (3.5±2.0) points, respectively, the combined treatment group were (7.6±1.1), (6.8±1.4), (5.4±1.8) points, the two groups were compared at different time points, the difference was statistically significant (F=26.509, P<0.05 ), there was statistically significant difference between the two groups at different time points (F=8.973, P=0.008). Before treatment, 2 months after the first laser treatment and 2 months after the second laser treatment, the blood vessel distribution scores of the POSAS scores of the laser treatment group were (4.4±2.1), (3.9±0.9), (3.5±1.6) points, the combined treatment group were (6.3±1.1), (5.7±2.0), (4.5±1.6) points. There was statistically significant difference between the two groups at different time points (F= 20.118, P<0.05), and between the two groups at different time points, the difference was statistically significant (F= 5.744, P= 0.028).

Recombinant human epidermal growth factor gel combined with CO₂ fractional laser and CO₂ fractional laser alone have clear effects in the treatment of hypertrophic scars, but the combined use of recombinant human epidermal growth factor gel can effectively promote wound healing, improve vascular distribution of scar tissue and reduce local pigmentation.