Comparison Between Posterior And Anterior Cervical Approaches For Establishing A Rat Model Of Neuropathic Pain After Brachial Plexus Avulsion Injury

Objective: Cervical laminectomy is a common posterior approach for addressing cervical spondylotic myelopathy.This surgical method was modified to establish a rat model of neuropathic pain following brachial plexus avulsion injury,which was considered as the most severe form of peripheral nerve injury.The aim of the study is to compare posterior and anterior cervical approaches for establishing the rat model following brachial plexus avulsion injury in terms of the incidence of neuropathic pain.Methods: All rats(45)were divided randomly into three groups,posterior-cervical-approach group(20),anterior-cervical-approach group(20),and sham-operated group(5).Mechanical allodynia and cold allodynia tests were performed before surgery(0 day)and 1,4,7,10,13,16,19,22,25,28,31 days after surgery,and the activation of astrocyte and microglia in cervical spinal cord on injured level was observed 1 month(31 days)after surgery.Results: Behavioral tests suggested that 20% of rats in posterior-cervical-approach group and 5% of rats in anterior-cervical-approach group developed neuropathic pain,with a drop in mechanical threshold and a rise in cold allodynia score about 3 weeks postoperatively.Astrocyte and microglia were significantly activated in cervical cords of the rats developed neuropathic pain.Therefore,results of behavioral tests and immunohistochemistry can verify the existence of neuropathic pain in rats.Conclusion: The rat model following brachial plexus avulsion injury,established in posterior cervical laminectomy,can develop neuropathic pain easily and could be applied to provide evidence for further clinical intervention and treatment.