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Published on: January 27, 2023
Visualizing the Pharmacologic Preconditioning Effect of Botulinum Toxin Type A by Infrared Thermography in a Rat
Miao Chen1, Xiucun Li1, Zhenmin Jiang1
1From the Department of Hand and Foot Surgery, The First Hospital of Jilin University; Jilin Province Key Laboratory on Tissue Repair, Reconstruction, and Regeneration; and the Department of Hand and Foot Surgery, The Second Hospital of Shandong University.
Background:
Surgical delay can improve flap viability, leading to vasodilation, neovascularization, and vessel reorganization. Experiments suggest a similar positive effect of botulinum toxin type A on pedicled flap viability. However, whether it may convert choke anastomoses into true anastomoses and how to identify the optimal timing for flap transfer remain unclear.
Methods:
One hundred fifty-four Sprague-Dawley rats were divided into a control group, three saline injection groups, and three botulinum toxin type A injection groups defined by time of injection (2, 3, and 4 weeks before flap harvest). A pedicled 11 × 3-cm flap was marked on the unilateral dorsum of each rat. Before flap harvest, the flap donors were assessed by infrared thermal imaging, postmortem arteriography, immunohistochemical staining of CD31, and enzyme-linked immunosorbent assay. Flap survival area percentage was measured on postoperative day 7.
Results:
In the control and saline groups, infrared thermography showed three independent white hotspots interspaced by red zones over flaps, whereas it presented a continuous white band in the botulinum toxin type A groups. There was a significant increase in flap survival area, flap surface temperatures, numbers of identifiable vessels in the choke zones, microvascular density, and vascular endothelial growth factor concentration in the botulinum toxin type A groups.
Conclusions:
Botulinum toxin type A can convert choke anastomoses into true anastomoses, and its preconditioning effect cannot increase over time; it is appropriate to choose the timing point when the infrared thermal images show a continuous white band existing over flaps for flap transfer.
