脊髓中央裂电刺激对股二头肌的控制作用

Control action of electrostimulation in central fissure of spinal cord on biceps femoris

目的:通过对兔损伤平面以下脊髓中央裂电刺激实现对股二头肌牵张反射和收缩功能的控制作用。方法:实验于2003-11/2004-03在济南军区总医院动物实验中心完成,12只新西兰大白兔(8月龄)手术制作兔T10截瘫模型,术后10d,暴露L4～S2脊髓,植入长短两组微电极,然后暴露兔双侧股二头肌远端止点,用50mg砝码10cm高垂直坠落诱发牵张反射,肌电诱发电位仪记录兔股二头肌牵张反射的运动单元电位及刺激短电极后的运动单元电位,纪录刺激前后运动单元电位的电压值进行配对比较。在兔双侧足部捆绑50mg砝码行长电极刺激后,观察诱发兔股二头肌负重收缩结果,抑制兔股二头肌牵张反射的结果,并记录最小的刺激电压值。结果:入选的12只兔均进入结果分析。①兔股二头肌牵张反射结果:短电极在方波波宽0.1ms,频率60～150Hz,电压80～120mV刺激下,牵张反射的运动单元电位的平均电压值低于兔截瘫后10d不给予电刺激时的平均值[(264±81),(267±61)μV,(t=2.628P<0.05)]。②诱发兔股二头肌负重收缩观察结果:长电极在波宽为0.4ms,频率30～50Hz,最小刺激电压(31.00±4.48)mV时,兔股二头肌发生负重收缩。结论:采用脊髓中央裂电刺激的方法可以使股二头肌获得可控制的反射抑制和肌肉运动功能。

AIM： To control the deep reflex and contraction function of biceps femoris in rabbits by electrostimulation in central fissure of spinal cord under the injury level. METHODS： The experiment was done at Animal Experiment Center of General Hospital of Jinan Military Area Command of Chinese PLA between November 2003 and March 2004. Twelve New Zealand rabbits （aged 8 months） were used to make rabbit T10 paraplegia model by operation. Ten days after operation the spinal cord was exposed L4-S2 and implanted into two groups of microelectrodes, that was, long and short. Both side distal end of biceps femoris was exposed and stimulated stretch reflex by 50 mg counterweight vertically falling from 10 cm high. The movement dement potential beth of deep reflex of rabbit biceps femoris and after the stimulation of short electrode was recorded by muscle electric induced potential meter. The voltage value of movement element potential before and after stimulation was recorded and compared by pair-matching. Fifty mg counterweight was fixed at each side of rabbit＇s foot after the stimulation of long electrode. The evoked weight contraction of rabbit biceps femoris was observed, thus, the result of deep reflex of rabbit biceps femoris was inhibited, and the lowest voltage was recorded. RESULTS： The selected 12 rabbits were all involved in the result analysis. ① The result of deep reflex of rabbit biceps femoris： The short electrode under the stimulation of the range of square wave was 0.1 ms with 60-150 Hz frequency and 80-120 mV voltage. The average of voltage of movement element potential of stretch reflex was lower than the average value when the dectrostimulation was not given 10 days after rabbit paraplegia [（264±81）, （267±61）μV, （t =2.628 P 〈 0.05）]. ② The observation result of the evoked weight loading contraction of rabbit biceps femoris： The weight loading contraction of rabbit biceps femoris occurred when the range of wave was 0.4 ms with 30-50 Hz frequency and （31±4.48） mV minimal stimulus voltage. CONCLUSION： The biceps femoris muscle can obtain the controllable reflex inhibition and muscular movement function with the method of dectrostimulation in central fissure of spinal cord.