A rat model of modified contralateral C7 transfer permitting ulnar nerve recovery

Abstract

BackgroundContralateral C7 transfer (cC7) is an important treatment for total brachial plexus avulsion (TBPA), which sacrifices the recovery of the ulnar nerve (UN). The present study aimed to introduce an animal model of modified cC7 that preserved the deep branch of ulnar nerve (dbUN) and verify its feasibility. MethodsAnatomical study: Lengths, diameters, and axon counts of dbUN and anterior interosseous (AIN) branches in six rats were measured.In vivo surgery: 18 rats were divided into three groups. Group A: Traditional cC7. Group B: Modified cC7 finished in one stage. Group C: Modified cC7 and AIN branch anastomosed with dbUN one month after the first stage. Electrophysiological examinations, muscle wet weight, muscle cross-sectional areas, and nerve axon counts were evaluated six months postoperatively. ResultsAnatomical study: The distances from dbUN and AIN branches to the midpoint of the inner and outer epicondyles connection of the humerus, diameters, and axon numbers of dbUN and AIN branches were analyzed, then AIN terminal branch (tbAIN) was anastomosed with dbUN.In vivo surgery: The differences in median nerve fiber counts were not significant. There were more UN axons in group A than in groups B and C. In electrophysiological examinations, muscle wet weight and cross-sectional area of the flexor digitorum profundus showed no significant difference, but the second interosseus cross-sectional areas in groups B and C were significantly larger than in group A. ConclusionsThis study established an animal model of preserving dbUN in cC7 and verified its feasibility. The possibility of restoring dbUN was established.