Reply: Visualizing the Pharmacologic Preconditioning Effect of Botulinum Toxin Type A by Infrared Thermography in a Rat Pedicled Perforator Island Flap Model.

Abstract

Sir: We appreciate the comment on our study entitled “Visualizing the Pharmacologic Preconditioning Effect of Botulinum Toxin Type A by Infrared Thermography in a Rat Pedicled Perforator Island Flap Model.”1 Dr. Ince et al. proposed that botulinum toxin type A should be injected into the sites where the choke anastomoses between interperforator angiosomes are located instead of the borders of the planned flap. We agree with their proposal because, in this way, the dosage of botulinum toxin type A can be reduced. However, it is unclear whether injection of botulinum toxin type A in the choke zones may induce the conversion from choke anastomoses into true anastomoses, and we will test it as soon as possible. The aim of our study was to explore whether botulinum toxin type A injection may convert choke anastomoses into true anastomoses, and if so, whether the optimal timing for definitive surgery can be identified in vivo with the aid of infrared thermography. Our study has shown that the flap donors after preconditioning by botulinum toxin type A presented a continuous white band on infrared thermography when choke anastomoses were converted to true anastomoses as shown by postmortem arteriography. Thus, we can identify the optimal timing for flap surgery based on this infrared thermographic change over the flap donors. In this study, a possible mechanism of the conversion from choke anastomoses to true anastomoses after preconditioning is the vasodilative effect of botulinum toxin type A by blocking the release of acetylcholine and norepinephrine. In addition, we found a significant increase in vascular endothelial growth factor expression in the flap donors after preconditioning by botulinum toxin type A. We do not know why the expression of vascular endothelial growth factor was increased after injection of botulinum toxin type A, and our research is ongoing. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication.