Inflammatory Response and Survival of Pedicled Abdominal Flaps in a Rat Model after Perivascular Application of Botulinum Toxin Type A

Background: In addition to the numerous applications of botulinum toxin type A, the authors have documented improvements in surgical flap survival through vasoactive effects. This study aimed to investigate its effect on the expression of inflammatory mediators. Methods: In 54 male Sprague-Dawley rats, cutaneous flaps based on the superficial epigastric vessels were elevated. Botulinum toxin type A, lidocaine, or saline was administered to the vascular pedicle. After 1, 2, and 7 days, mRNA expression for tumor necrosis factor-, interleukin-1, and vascular endothelial growth factor-165 was compared along with flap survival. Results: Vascular endothelial growth factor-165 mRNA expression was lower in the botulinum toxin type A group compared with (1) the saline group at days 1 and 2 (p < 0.01) and (2) the lidocaine group at day 2 (p < 0.05). The expression of interleukin-1 was significantly less at each time point in the botulinum toxin type A group compared with the lidocaine group (p < 0.02), and at day 2 compared with the saline group (p < 0.01). Tumor necrosis factor- mRNA expression in the botulinum toxin type A group was lower at 2 days and 7 days compared with both other groups (p < 0.04). Finally, both the botulinum toxin type A and lidocaine groups had a greater survival area (p < 0.05) compared with the saline group. Conclusion: The presence of botulinum toxin type A in the postsurgical flap microenvironment augments tissue perfusion and its inflammatory response and, ultimately, survival.