Anatomical and functional connectivity of the transected ulnar nerve after accessory nerve neurotization in the cat.

ABSTRACT

AIM: The objective of this experimental study was to test the capacity of accessory nerve motoneurons to innervate muscles of the ulnar nerve territory after direct anastomosis. METHODS: This study used 22 cats in two groups experimental group (15 cats) and control group (7 cats). The first one was followed during twelve months using electromyographic records every two months postsurgery; muscle and nerve histological assessment and counting horseradish peroxidase-labeled motoneurons. RESULTS: Our results showed that reinnervation was achieved in 12/15 nerves. The number of HRP labelled medullar motoneurons after anastomosis showed a significant statistic difference with a simple ulnar nerve transection; there was no significant statistic difference in labelling between the group with an anastomosis and the one with a simple accessory nerve transection. CONCLUSIONS: Direct anastomosis between the spinal accessory nerve and the ulnar nerve is achievable and thus, the accessory spinal nerve is another possible choice for correcting the motor deficit arising from lower brachial plexus avulsion, but the limited number of motoneurons would only allow partial reinnervation..