Lack of neuroprotection with pharmacological pretreatment in a paradigm for anticipated spinal cord lesions

Background: In humans elective spine surgery can cause iatrogenic spinal cord injury (SCI). Efforts for neuroprotection have been directed to avoid mechanical injury by using intraoperative monitoring and improving surgical techniques. There is, however, uncertainty regarding the efficacy of neuroprotective drugs. Study design: Experimental study on the effectiveness of pharmacological neuroprotection in an animal model of spine surgery simulating anticipated mechanically induced neurological damage. Objective: To compare the efficacy of four drugs to protect against the neurological effects of iatrogenic SCI. Setting: Research Unit for Neurological Diseases, IMSS-Proyecto Camina, Mexico City, Mexico. Methods: Erythropoietin, melatonin, cyclosporine-A and methylprednisolone were administered to rats before, during and after controlled spinal cord contusion of mild intensity. Dosage was in accordance with their pharmacokinetic properties and experience gained with experimental SCI. Drug efficacy was assessed by motor function recovery over a period of 6 weeks and by spinal cord morphometry. Results: Compared with animals treated with saline, the drug-treated groups showed no differences in their locomotor performance, nor in the amount of spared cord tissue. Notably, spontaneous activity was significantly reduced in rats treated with cyclosporine-A. Conclusion: The neuroprotectant drugs used here perioperatively did not reduce the extent of neurological damage in a model simulating iatrogenic SCI. Therefore, for now, the only protection in elective spine surgery is avoidance of primary injury altogether.