Objective To study the results of several operative methods (neurolysis,nerve repair and nerve grafting) for the treatment of the ligated peripheral nerves using rat models.Methods A total of 144 rats were randomly assigned to 3 groups:neurolysis group,nerve repair group and nerve grafting group.Ligation of the sciatic nerve was done first in all the animals to establish the nerve injury model.After 2 weeks,a second surgery was carried out to treat the nerve lesion.Neurolysis,nerve repair or nerve grafting was carried out according to group assignment.The rats were sacrificed at postoperative week 1,2,4,6,8,10 and 12 respectively.Weight of the gastrocnemius muscle was measured and the myelinated nerve ftber cotmt of the sciatic nerve was evaluated.Results were analyzed statisticafly to make comparison among the groups.Results Gastrocnemius muscle weight recovered after 12 weeks of single ligation of the sciatic nerve in the control group in which no treatment was carried out.Muscle weight and myelinated nerve fiber count,however,did not show obvious increase in the double ligation group where multiple lesion of the sciatic nerve was created but not treated.In the neurolysis group,4 and 6 weeks after the second procedure,gastrocnemius muscle weight and myelinated fiber count of the sciatic nerve of the experimental side were significantly higher than those of the contralateral side.In the nerve repair group,at 6 weeks after the procedure,gastrocnemius muscle weight of the experimental side was significantly higher than that of the contralateral side,whereas the sciatic nerve myelinated fiber count was not significantly different.In the nerve grafting group,gastrocnemius muscle veight of the experimental side was significantly higher than that of the contralateral side at 6 weeks after the procedure,while the sciatic nerve myelinated fiber count was signfificantly better at 12 weeks.Conclusion For ligation induced stenosis of the peripheral nerve,surgical intervention should be considered proactively if there is no improvement after 12 weeks of conservative treatment.Neurolysis would lead to better results than conservative treatment and is the recommended procedure.The results of nerve repair are not certain.Thus this procedure should be chosen with caution.For multiple or wide range stenosis of the nerve,resection of the lesion area and nerve grafting should be the treatment of choice.