Establishment of an animal model of extra-vertebral foramen cervical nerve entrapment by local electrical stimulation and selection of suitable stimulation parameters

摘要

A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters:stimulation intensity 20 V;frequency 50 Hz;pulse width 200 μs;duration 333 ms/s for a total of 8 hours.After the electrical stimulation,rats exhibited mild muscle fiber atrophy,mild inflammatory exudates,connective tissue local fibrosis and chondrocyte metaplasia.Mean muscle fiber cross-sectional area was reduced.The nerve myelin sheath continuity was partially demyelinated.The microstructure of nerve cells was disrupted and these symptoms worsened with prolongation of the stimulation.The shoulder,neck and upper extremity muscles on the tested side demonstrated positive sharp waves and fibrillations.The severity increased with continuation of the stimulation.High amplitude and polyphasic motor unit potentials gradually appeared.Similar findings were seen in the contralateral side,but at a less severe level.