大鼠分级脊髓损伤对经颅电刺激运动诱发电位的影响

目的 了解不同程度脊髓损伤（ＳＣＩ）对运动诱发电位（ＭＥＰ）的影响以及ＭＥＰ对ＳＣＩ运动功能预后的价值。方法 采用改良Ａｌｌｅｎ′ｓ法,分别以３０ｇｃｆ、５０ｇｃｆ、８０ｇｃｆ和１００ｇｃｆ冲量打击４０只ＳＤ大鼠Ｔ８￣９脊髓,造成不同程度ＳＣＩ,于伤前及伤后１个月连续记录Ｌ１￣２脊髓硬膜外ＭＥＰ（ｓｃＭＥＰ）和双侧腓肠肌ＭＥＰ（ｍＭＥＰ）,并采用斜板试验和Ｔａｒｌｏｖ评分评估运动神经功能。结果（１

The effects of graded spinal cord injuries on transcranial electric stimulation motor evoked potentials in the rat

OBJECTIVE: To study the effects of graded spinal cord injury (SCI) on the motor evoked potentials (MEP) characteristics and the prognostic value of MEP for the motor function. METHOD: Modified Allen's method was used by weight drop force of 30 gcf, 50 gcf, 80 gcf and 100 gcf on the T(8 - 9) spinal cord of 40 SD rats in order to make SCI models. MEP was recorded continuously at L(1 - 2) epidurally and bilateral gastrocnemius muscles before and after the spinal cord lesion was produced (followed up for 1 month). The inclined plane and Tarlov technique were used to assess clinical neurological function. RESULT: The amplitude of rat's MEP changed significantly with graded SCI, the more sever the lesion, the lower the potentials. mMEP was more sensitive than scMEP, though the abolishment of mMEP soon after SCI didn't indicate that the animals could not regain ambulation. Changes in amplitude of scMEP recorded early after SCI were collaborate significantly with inclined plane (gamma = 0.9665, P < 0.01) and Tarlov scale (gamma = 0.8893, P < 0.01) assessed 1 month later, and can be used as a chronic measure parameter of motor function prognosis. scMEP still existed 1 month after SCI in 3 of 11 rats (27.3%) without any voluntary movement in bilateral hindlimbs, suggesting that some parts of conductive function still existed in the spinal cord. So it should be called "discomplete SCI". CONCLUSIONS: scMEP can be used as a reliable parameter for motor function prognosis, because it reflects objectively and sensitively the severity of central motor neurol fiber injury.