Brachial Plexus Lesion: Experimental Model

The sequelae produced by injuries of the brachial plexus are of extreme importance in Brazil. The number of accidents involving motorcycles grows larger every day and the current statistics are frightening. The search for functional results that are better for this kind of injury made several authors develop surgical techniques based on scientific trials that are becoming more and more elaborate and precise. The detailed knowledge of brachial plexus anatomy in the rat has made it a better experimental animal for use in this area. A trial model was developed involving a partial injury of the brachial plexus in a rat model, seeking more precise approaches to the median and ulnar nerves.

Forty Wistar rats were utilized in this project, divided into two experimental groups: (1) an avulsion group in which avulsions of the C8 and T1 (lower trunk) roots were made with a Halsted tweezer; (2) a control group in which no surgical procedure was carried out, only a strength evaluation. The animals were sacrificed at 180 days. They were submitted to a strength evaluation with the “grasping test,” to electromyographic analysis of the dependent muscle of the median nerve, and to histologic analyses of the flexor muscle of the fingers, along with a part of the lower trunk nerve.

The use of electromyography, use of the “grasping test,” and optical microscopy were the chosen methods to validate partial denervation of the lower trunk of the rat brachial plexus. With them, this experimental model of partial denervation of the rat brachial plexus was validated. It could be used further in studies that seek the elaboration of surgical techniques that are efficacious for the treatment of these injuries.

There are many experimental projects reported in the current medical literature in which authors have elaborated hypotheses based on total injuries of the brachial plexus in a rat model. The creation of an experimental model of partial injuries of the brachial plexus in rats may support further research about situations that are very common to the treatment of these injuries in humans.