Evaluation of ventral root reimplantation as a treatment of experimental avulsion of the cranial brachial plexus in the dog

This in vivo experimental study was carried out 1/ to evaluate the ability of dog spinal neuron to grow an axon into reimplanted brachial plexus ventr al root, and 2/ to assess the functional outcome after root reimplantation. The reimplantation of C5, C6 and C7 ventral rootlets was carried out after their avulsion in 6 dogs (group 1) and three other dogs were used as sham control (group 2). Axonal regrowth in the roots was assessed by Horse Radis h Peroxidase (HRP) retrograde tracing studies and muscular reinnervation wa s tested by electrophysiology. Functional recovery was evaluated by clinica l examination and muscle weight (in comparison to 12 normal dogs cadavers : group 3). HRP-tracing methods demonstrated axonal regrowth into the reimplanted roots by (moto)neurons confined in the ipsilateral ventral hom. In group 1, EMG investigations showed signs of reinnervation and neuronal labelling was obs erved. In group 2, there were no signs of reinnervation by EMG and no neuro nal labelling. In addition, amyotrophy was more severe in group 2. No sign of functional recovery was observed in either of the two groups. Our findin gs demonstrate that root reimplantation may promote muscular reinnervation in the dog after brachial plexus avulsion.