Nerve Injury and Regeneration after Neurolysis: Ethanol Alone versus Ethanol with Brachytherapy in Rabbits

This study aimed to prove the hypothesis that neurolysis based on ethanol injection in combination with iodine-125 (¹²⁵I) radioactive seed implantation could prolong the nerve regeneration time compared with that based on ethanol injection alone. The grade of nerve injury was assessed for both methods.

Twenty female rabbits (mean weight, 2.8 kg ± 0.2) were randomly assigned to group A (neurolysis of the left brachial plexus nerve based on ethanol injection in combination with ¹²⁵I radioactive seed implantation, n = 10) and group B (neurolysis using ethanol injection alone, n = 10). The right brachial plexus nerve was used as a control. Injury and regeneration of the brachial plexus nerve were analyzed using electromyography. Statistical tests were performed using the Mann-Whitney U test and repeated-measures analysis of variance. The results were verified with histopathological examinations.

The overall postprocedural amplitude was significantly lower in group A than in group B (P = .01), particularly in the second month after the procedure (P = .036). However, no statistical difference in latency was observed between the 2 groups (P = .103). Histopathological examination of both groups revealed Sunderland third-degree peripheral nerve injury (PNI), which was mainly characterized by axonal disintegration. The degree of nerve regeneration was significantly lower in group A than in group B.

Neurolysis based on ethanol injection in combination with ¹²⁵I radioactive seed implantation can prolong the nerve regeneration time compared with that based on ethanol injection alone, although both methods resulted in Sunderland third-degree PNI.