Changes of nerve root blood flow during discectomy for lumbar disc herniation

Objective:To investigate the relation between nerve root blood flow changes during discectomy and clinical features associated with lumbar disc herniation.Method:Nerve root blood flow was intraoperatively measured before and after discectomy for lumbar disc herniation in 24 patients using laser Doppler flowmetry during discectomy.Possible correlations were investigated.Result:The increase in nerve root blood flow in patients whose neurologic deficits resolved or whose leg pain did relieve soon after the operation was greater than that in patients whose neurologic deficit did not recover or whose leg pain did not relieve soon after the operation.The increase in nerve root blood flow in patients whose herniated discs had ruptured the posterior longitudinal ligament (PLL) was found to be significantly greater than that in patients whose herniated discs had not ruptured the PLL.Conclusion:The results suggest that immediate relief from leg pain and resolution of neurologic deficits soon after surgery are the result of early recovery from nerve root ischemia after discectomy,and that ischemia caused by mechanical nerve root compression is mainly related to the mechanisms underlying sciatic pain and/or numbness production and neurologic deficits.