Model for avulsion injury in the rat brachial plexus using passive acceleration

We have developed an experimental model for brachial plexus injuries in the rat that closely simulates the characteristics of human injury. This model produces avulsion injuries in a noninvasive manner. A prototype apparatus was designed that allowed a force to be transmitted to a restrained limb by passive acceleration. Reproducible results were obtained in 32 rats. A sig nificant correlation was found between the test weight and the number of ro ots avulsed (r = 0.92; P < 0.05). The amount of force also correlated to th e pattern of avulsion injury: a 230-g weight produced either C6 (54%), C7 ( 15%), or C6 and C7 (31%) avulsions; a 330-g weight produced C6 (18%), C7 (9 %), or C6 and C7 (73%) avulsions; a 530-g weight produced C5 through C8 (75 %) or C6 through T1 (25%) avulsions. This model of brachial plexus injury m ay be useful to further our understanding of the cellular response to this incapacitating injury and to develop therapeutic strategies with behavioral correlates.