BACKGROUND:Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries.The established ventral approach results in slight injuries,and is similar to mechanisms underlying human brachial plexus root avulsion.OBJECTIVE:To analyze the effects of weight,age,and species on the success rate of brachial plexus root avulsion,and to determine the perfect method for establishing models of brachial plexus root avulsion.DESIGN,TIME AND SETTING:A randomized,block design was performed at the Laboratory of Professor Lihua Zhou,Zhongshan School of Medicine,Sun Yat-sen University,China from June 2008 to June 2009.MATERIALS:Sprague Dawley(SD) rats,golden hamsters,and BALb/C mice were used in the present study.METHODS:All animals were randomly subjected to classical brachial plexus root avulsion and modified brachial plexus root avulsion.MAIN OUTCOME MEASURES:Success rate of brachial plexus root avulsion.RESULTS:The success rate of brachial plexus root avulsion was greater in the modified group than in the classical group(P < 0.01).Moreover,the difference was significant in 15-day-old SD rats,5-week-old SD rats,and 3-month-old BALb/C mice(P < 0.01).The success rate of brachial plexus root avulsion was greater in the same weight,15-day-old juvenile SD rats,than in the 3-month-old BALb/C mice(classical group,P < 0.01;modified group,P < 0.05).The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group(P < 0.05).The success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group(P < 0.01).However,there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group(P > 0.05).CONCLUSION:Modified surgery to induce brachial plexus root avulsion significantly increases the success rate of model establishment.Species,age,and weight affect the success rate of brachial plexus root avulsion,and species plays an important role in the success rate. BACKGROUND: Animal models of brachial plexus root avulsion are required for the study of brachial plexus root lesions. The established ventral approach results in slight injuries, and is similar to the procedure that the underlying human brachial plexus root avulsion. OBJECTIVE: To analyze the effects of weight, age, and species on the success rate of brachial plexus root avulsion, and to determine the perfect method for establishing models of brachial plexus root avulsion. DESIGN, TIME AND SETTING: A randomized, block design was performed at the Laboratory of Professor Lihua Zhou, Zhongshan School of Medicine, Sun Yat-sen University, China from June 2008 to June 2009. MAIALIALS: Sprague Dawley (SD) rats, golden hamsters, and BALb / C mice were used in the present study. METHODS: All animals were randomly selected to classical brachial plexus root avulsion and modified brachial plexus root avulsion. MAIN OUTCOME MEASURES: Success rate of brachial plexus root avulsion .RESULTS: The success rate of brachial plexus root avuls ion was greater in the modified group than in the classical group (P <0.01). Coreover, the difference was significant in 15-day-old SD rats, 5-week-old SD rats, and 3-month-old BALb / C The success rate of brachial plexus root avulsion was greater in the same weight, 15-day-old juvenile SD rats, than in the 3-month-old BALb / C mice (classical group, P <0.01 ; modified group, P <0.05) .The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group (P <0.05). success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group (P <0.01) .However, there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group (P> 0.05). CONCLUSION: Modified surgery to induce brachial plexus root avulsion significantly increases thesuccess rate of model establishment. age, and weight affect the success rate of brachial plexus root avulsion, and species plays an important role in the success rate.