胫后神经体感诱发电位对脊髓病变的定位诊断

Posterior tibial nerve somatosensory evoked potentials in the topical diagnosis of different segmental spinal cord lesions

目的：研究胫后神经体感诱发电位（ＳＥＰ）对脊髓病变的定位诊断价值。方法：电刺激胫后神经，于腰椎、胸椎、颈椎和头皮置记录电极，依次记录ＣＥ，Ｎ２４，Ｎ２８和Ｐ４０电位峰潜伏期。共检测１５例对照组和２９例经磁共振（ＭＲＩ）证实的腰骶神经根或脊髓病变患者。结果：（１）ＣＥ，Ｎ２４，Ｎ２８和Ｐ４０电位均异常，见于腰骶神经根病变。（２）ＣＥ正常，Ｎ２４，Ｎ２８和Ｐ４０异常，或Ｎ２４异常，余电位均正常，见于腰骶髓病变。（３）ＣＥ，Ｎ２４正常，Ｎ２８和Ｐ４０异常，见于胸髓病变。（４）ＣＥ，Ｎ２４，Ｎ２８正常，Ｐ４０异常，见于第６颈椎以上病变。

Objective: To study the value of posterior tibial nerve somatosensory evoked potentials (SEP) in the diagnosis of spinal cord lesions. Methods: Posterior tibial nerve SEP s (CE, N24, N28, P40), elicited by constant electric stimulation of posterior tibial nerve at the ankle, were recorded by the electrodes in the lumbar vertebra, thoracic vertebra, cervical vertebra and scalp. Fifteen controls and 29 patients with lumbosacral radiculopathies or spinal cord lesions verified by MRI, were examined. Results: (1) Abnormal CE, N24, N28 and P40 were observed in the patients with lumbosacral radiculopathy; (2) Normal CE and abnormal N24, N28 and P40 or normal CE, N28 and P40, and abnormal N24 were observed in the patients with lumbosacral cord lesions; (3) Normal CE and N24, and abnormal N28 and P40 were observed in the patients with spinal cord lesions from the 6th cervical vertebra to the 12th thoracic vertebra; (4) Normal CE, N24 and N28, and abnormal P40 were demonstrated in the patients with spinal cord lesions above the 6th cervical vertebra. Conclusion: Posterior tibial nerve SEP has a topical diagnostic value for spinal cord lesions, but in slight lumbosacral radiculopathies or ventral spinal cord lesions, a false negative SEP may occur.