1. Modeling material animal: Wistar rat, male, weighing 200-250g; drug: pentobarbital.
2. Modeling method Weigh the model animals separately, anesthetize them, inject sterilized pentobarbital intraperitoneally, separate the right sciatic nerve, and the branches of the common peroneal nerve and tibial nerve under an operating microscope, and separate the central edge. Gently ligate the sympathetic nerve trunk by 1 mm with 4-0 chromium catgut. Under the microscope, the gut is in contact with the superior nerve membrane. There are 3-4 ligation points, each of which is about 2 mm apart.
3. Modeling principles Nerve trunk ligation leads to chronic pain in animals.
4. Changes after modeling. Model animals usually start self-cutting or pain response after 7-10 days.