Hirayama J, Takahashi Y, Nakajima Y, Takahashi K, Yamagata M, Moriya H
Physiology, School of Medicine, Chiba University, Chiba, Japan.
Spine (Phila Pa 1976). 2001 Mar 15;26(6):602-9. doi: 10.1097/00007632-200103150-00009.
The effects of electrical stimulation of the sciatic nerve on background electromyographic and static stretch reflex activity of the trunk muscles were studied.
To verify the hypotheses that sciatic scoliosis is induced reflexively by radiculopathic pain, and that scoliosis might be maintained by prolonged asymmetric alteration of the trunk muscle tonus caused by central sensitization of the spinal neurons that constitute the postural reflex pathways.
Sciatic scoliosis usually occurs with convexity to the side of the herniated disc. The neuronal mechanism of sciatic scoliosis has not been well clarified. Recently, prolonged alteration of motor function in the hindlimbs of animals caused by central sensitization has been reported.
In spinalized rats (transection of the spinal cord), the sciatic nerve was stimulated electrically as a conditioning stimulus. Muscle stretch elicited by bending of the lumbar spine was applied as a test stimulus. Background and stretch reflex activities of the bilateral oblique abdominal, psoas, and quadratus lumborum muscles were recorded. Rats in which MK-801, an N-methyl-d-aspartate antagonist, was preadministered also were used.
The conditioning stimulus enhanced background electromyographic activity in bilateral oblique abdominal, contralateral psoas, and quadratus lumborum muscles. Furthermore, the conditioning stimulus induced prolonged facilitation and depression of stretch reflex activity of the contralateral psoas and quadratus lumborum, and ipsilateral psoas and quadratus lumborum muscles, respectively. Preadministration of MK-801 reduced these excitatory and inhibitory effects.
It was found that the pattern of electromyographic activity of the trunk muscles evoked by sciatic nerve stimulation coincided with the typical direction of sciatic scoliosis in patients with lumbar disc herniation. It was supposed that the prolonged asymmetric alteration of the trunk muscle tonus was caused by central sensitization, and that central sensitization of spinal neurons may underlie the neuronal mechanism of sciatic scoliosis.
研究了坐骨神经电刺激对躯干肌肉背景肌电图和静态牵张反射活动的影响。
验证以下假设，即坐骨神经型脊柱侧凸是由神经根性疼痛反射性诱发的，并且脊柱侧凸可能是由构成姿势反射通路的脊髓神经元中枢敏化导致的躯干肌肉张力长期不对称改变所维持的。
坐骨神经型脊柱侧凸通常凸向椎间盘突出侧。坐骨神经型脊柱侧凸的神经机制尚未完全阐明。最近，有报道称中枢敏化会导致动物后肢运动功能的长期改变。
在脊髓横断大鼠（脊髓横切）中，电刺激坐骨神经作为条件刺激。通过腰椎弯曲引起的肌肉牵张作为测试刺激。记录双侧腹外斜肌、腰大肌和腰方肌的背景和牵张反射活动。还使用了预先给予N-甲基-D-天冬氨酸拮抗剂MK-801的大鼠。
条件刺激增强了双侧腹外斜肌、对侧腰大肌和腰方肌的背景肌电图活动。此外，条件刺激分别诱导了对侧腰大肌和腰方肌以及同侧腰大肌和腰方肌牵张反射活动的长期易化和抑制。预先给予MK-801可降低这些兴奋和抑制作用。
发现坐骨神经刺激诱发的躯干肌肉肌电图活动模式与腰椎间盘突出症患者典型的坐骨神经型脊柱侧凸方向一致。推测躯干肌肉张力的长期不对称改变是由中枢敏化引起的，并且脊髓神经元的中枢敏化可能是坐骨神经型脊柱侧凸神经机制的基础。
