A prospective randomized controlled clinical study on the treatment of hypertrophic scar after burn by fractional carbon dioxide laser combined with autologous fat injection

Objective To explore the clinical effects of fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn. Methods From April 2018 to April 2019, 12 patients with hypertrophic scar after burn who met the inclusion criteria were admitted to the Department of Plastic Surgery and Burns of Xuzhou Renci Hospital, and were included in this prospective randomized controlled clinical study. There were 7 males and 5 females with age of (32±11) years and scar area of (612±195) cm². One scar was selected from each patient and divided into two equal area scars, and they were divided into combined treatment group and laser alone group with 12 scars in each group according to the random number table. The scar in laser alone group was only treated with fractional carbon dioxide laser, while the scar in combined treatment group was injected with autologous granular fat and then treated with fractional carbon dioxide laser. Scars in the two groups were treated once every 2 months, totally 3 times. Before the first treatment and 6 months after the last treatment, the scars in the two groups were evaluated by modified Vancouver Scar Scale (mVSS), hematoxylin-eosin staining and color Doppler ultrasound. Six months after the last treatment, the curative effect of scars in the two groups was evaluated, and the effective number of scar treatment was calculated. The adverse reactions during the whole treatment were recorded. Data were statistically analyzed with independent sample

test, paired sample

test, and McNemar exact probability method test. Results Six months after the last treatment, the mVSS score of scars in combined treatment group was (4.5±0.4) points, which was significantly lower than (7.8±0.6) points in laser alone group (

=10.000,

<0.01). Six months after the last treatment, the mVSS scores of scars in combined treatment group and laser alone group were significantly lower than those before the first treatment ((13.5±0.7) and (13.8±0.6) points,

=8.805, 9.010,

<0.01). The effective number of scar treatment in combined treatment group was significantly more than that in laser alone group (

<0.05). There was no scar aggravation, infection, or other adverse reactions during the treatment of scars in both groups. Before the first treatment, the scars in both groups had large collagen, disordered arrangement, proliferation of capillaries, infiltration of some inflammatory cells, and disappearance of skin appendages. Six months after the last treatment, the scar collagen in both groups was sparse and orderly arranged, and the vascular density was reduced. The improvement of scars in combined treatment group was more obvious than that of laser alone group. Six months after the last treatment, the scar thickness in combined treatment group was significantly smaller than that in laser alone group (

=2.657,

<0.05). Before the first treatment, the blood flow of scars in both groups was abundant; 6 months after the last treatment, the blood flow of scars in combined treatment group was significantly less than that in laser alone group. Conclusions Fractional carbon dioxide laser combined with autologous fat injection in the treatment of hypertrophic scar after burn can significantly reduce the pain and itching symptoms of scar, and improve the thickness, texture, and congestion of scar. The combined treatment has synergistic effect and less adverse reactions, providing a more effective treatment for patients with hypertrophic scar.