Effect of fractional ablative carbon dioxide laser with lidocaine spray on skin flap survival in rats

Background: Lidocaine spray is a local anesthetic that improves random-pattern skin flap survival. The fractional ablative carbon dioxide laser (FxCL) produces vertical microchannels that delivers topically applied drugs to the skin. In this study, we hypothesized that FxCL therapy would enhance the lidocaine effect to improve random-pattern skin flap survival in rats. Methods: McFarlane random-pattern skin flaps were elevated in 48 rats, which were divided into four groups according to treatment: FxCL+lidocaine, FxCL, lidocaine, and nontreatment (control). On postoperative day 7, necrotic flap areas, the number of capillary vessels, and neutrophil count were evaluated. Anti-rat vascular endothelial growth factor (VEGF) and CD31 antibody activity were also evaluated by immunohistochemical staining. Results: Flap survival rate was $53.41%{\pm}5.43%$, $58.16%{\pm}4.80%$, $57.08%{\pm}5.91%$, and $69.08%{\pm}3.20%$ in the control, lidocaine, FxCL, and FxCL+lidocaine groups, respectively. Mean neutrophil count in the intermediate zone excluding the necrotic tissue was $41.70{\pm}8.40$, $35.43{\pm}6.41$, $37.23{\pm}7.15$, and $27.20{\pm}4.24cells/field$ in the control, lidocaine, FxCL, and FxCL+lidocaine groups, respectively. Anti-rat VEGF and CD31 antibody activity were the highest in the FxCL+lidocaine group. Conclusion: FxCL with lidocaine had a positive effect on random-pattern skin flap survival in rats. Thus, FxCL with lidocaine spray should be considered as a new treatment option to improve flap viability.