An experimental study about the incorrect electrophysiological evaluation following peripheral nerve injury and repair.

Objective: This experiment was designed to explore the reasons of incorrect electrophysiological evaluation following peripheral nerve repair.

Methods: Twenty-four New Zealand white rabbits were used and divided into 2 groups. The first group of animals underwent severance of gastrocnemius muscle nerve and only the medial branch of the nerve was anastomosed. The second group of rabbits underwent severance of the muscle nerve as well as sural nerve, then the proximal end of the sural nerve was anastomosed to the distal end of the muscle nerve. Electrophysiological and morphological methods were used to study these models 3 months after the operations.

Results: Electrophysiologic comparison of muscle action potential for group A and B showed a significant difference in the values (p < 0.05). Morphologic studies showed that the muscle weights of group B were significantly lower than those of group A, but the myelin thickness failed to show any statistical difference between the two groups.

Conclusion: Results suggested that one of the sources causing incorrect electrophysiological evaluation could be misdirected regeneration, resulting from a sensory fascicle anastomosing to a motor one or vice versa. The unfunctional regeneration showed low values of muscle action potentials (p < 0.05) as well as excessive fibrillation potentials, and marked atrophy of the muscles (p < 0.05).