Electrophysiologic evidence for an intersegmental reflex pathway between lumbar paraspinal tissues.
Electrophysiologic evidence for an intersegmental reflex pathway between lumbar paraspinal tissues.
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DOI：
10.1097/00007632-200202010-00005
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发表时间：
2002-02-01
期刊：
影响因子：
3
通讯作者：
Pickar, Joel G
中科院分区：
文献类型：
--
作者：
Kang, Yu-Ming;Choi, Woo-Sung;Pickar, Joel G
研究设计：电生理记录从麻醉猫的腰椎旁神经或肌肉获得，同时电刺激相邻腰椎节段的椎旁神经或小关节囊。各种方法被用来证明反射性质的神经和肌肉response.Objective：本研究的主要目的是寻求电生理证据相邻的腰椎节段之间的存在节段间反射。本研究的第二个目的是确认以前用于诱发椎旁反射的程序。以前的工作表明，电刺激L1-L2小关节囊elaborate肌电图活动从多裂肌一至两个脊椎节段尾部的刺激facet. Summary背景资料：生物力学方法强调需要脊柱稳定性，以避免可能引起下背部功能障碍的条件。我们有理由相信，脊椎节段之间的反射相互作用有助于腰椎椎旁组织的感觉运动整合。似乎也有理由相信，这些反射的改变或异常激发可能会导致与腰痛和椎旁肌肉痉挛相关的生物力学变化。方法：对23只α-氯阿洛糖麻醉的成年猫进行了实验。在8只猫的L3，L4和L5内侧分支从每个背支暴露，并放置在双极钩电极。在6只猫中，刺激L4内侧分支，并从L3内侧分支记录复合动作电位。在6只猫中的3只中，刺激L5内侧分支，并记录来自L3内侧分支的复合动作电位。在一只猫中，刺激L4内侧分支，并从L5内侧分支记录复合动作电位。在一只猫中，刺激L3内侧分支，并从L5内侧分支记录复合动作电位。在每个方案结束时，在刺激电极近端切割内侧分支，以确认复合动作电位本质上是反射性的，而不是由容积传导引发的。在15只猫中，使用三种方法来证实由腰椎小关节囊的电刺激诱发的多裂肌肌电图活动本质上是反射性的：1）通过麻醉感觉末梢的部位，即，小关节囊，2）通过鞘内注射利多卡因以阻断中枢神经传导，即，在椎管内，或3）通过切断传入通路，即，结果：电刺激支配最内侧腰段椎旁组织的背支内侧分支，可在支配最内侧腰段椎旁组织的背支内侧分支诱发复合动作电位。2和70 V之间的刺激电压是诱发复合动作电位所必需的。每种复合动作电位本质上都是反射性的，因为在其与刺激电极接触的近端切断腰内侧分支会消除每种复合动作电位。反射的传导速度范围为3.5 - 6.1 m/sec。电刺激腰椎关节囊诱发腰椎多裂肌肌电图活动。然而，鞘内注射利多卡因或横切背支内侧分支对肌电活动没有影响。注射利多卡因到小关节或到多裂肌周围的小关节（附近的刺激电极）显着降低的幅度的多裂肌electromyograph.CONCLUSION：这些结果表明，传入冲动的背支内侧分支反射性地改变传出活动到相邻的腰椎节段。这种节段间椎旁反射可跨越至少一个或两个椎体节段。这些数据表明，小关节囊的电刺激可能不会反射性地引起多裂肌活动，因为假定的反射通路的化学中断（鞘内利多卡因）和物理中断（神经切断）都不会减少或消除肌电图反应。刺激电流的体积传导可能在小关节囊的电刺激期间引起多裂肌活动。当使用神经脊旁组织的电刺激来引起反射肌肉活动时，必须进行适当的对照实验以清楚地证明反应的反射性质。
STUDY DESIGN: Electrophysiologic recordings were obtained from a lumbar paraspinal nerve or muscle in the anesthetized cat while electrically stimulating a paraspinal nerve or facet capsule in an adjacent lumbar segment. A variety of approaches were used to demonstrate the reflex nature of both the nerve and the muscle response.OBJECTIVE: The primary purpose of this study was to seek electrophysiologic evidence for the presence of intersegmental reflexes between adjacent lumbar vertebral segments. A second purpose of this study was to confirm a previous procedure used to evoke paraspinal reflexes. This previous work had shown that electrical stimulation of the L1-L2 facet joint capsule elicits electromyographic activity from multifidus muscle one to two vertebral segments caudal to the stimulated facet in a porcine preparation.SUMMARY OF BACKGROUND DATA: Biomechanical approaches have stressed the need for spinal stability to avoid conditions that could give rise to low back dysfunction. It seems reasonable to believe that reflex interactions between vertebral segments contribute to the sensorimotor integration of lumbar paraspinal tissues. It also seems reasonable to believe that alterations or abnormal elicitation of these reflexes could contribute to biomechanical changes associated with low back pain and paraspinal muscle spasm.METHODS: Experiments were performed on 23 alpha-chloralose anesthetized adult cats. In eight cats the L3, L4, and L5 medial branch from each dorsal ramus was exposed and placed on a bipolar hook electrode. In six cats the L4 medial branch was stimulated and a compound action potential was recorded from the L3 medial branch. In three of the six cats the L5 medial branch was stimulated and a compound action potential was recorded from the L3 medial branch. In one cat the L4 medial branch was stimulated and a compound action potential was recorded from the L5 medial branch. In one cat the L3 medial branch was stimulated and a compound action potential was recorded from the L5 medial branch. At the end of each protocol the medial branch was cut just proximal to the stimulating electrode to confirm that the compound action potential was reflexive in nature and not initiated by volume conduction. In 15 cats three approaches were used to confirm that multifidus electromyographic activity evoked by electrical stimulation of a lumbar facet capsule was reflexive in nature: 1) by anesthetizing the site of the sensory endings, i.e., the facet capsule, 2) by injecting lidocaine intrathecally to block neural conduction centrally, i.e., within the spinal canal, or 3) by cutting the afferent pathway, i.e., the medial branch of the dorsal ramus.RESULTS: Electrical stimulation of the medial branch of the dorsal ramus innervating the medial-most lumbar paraspinal tissues evoked a compound action potential in the medial branch innervating the medial-most paraspinal tissues one and two segments away. Stimulating voltages between 2 and 70 V were necessary to evoke the compound action potential. Each compound action potential was reflexive in nature because cutting the lumbar medial branch proximal to its contact with the stimulating electrode abolished each compound action potential. The conduction velocity of the reflex ranged from 3.5 to 6.1 m/sec. Electrical stimulation of a lumbar facet capsule evoked lumbar multifidus muscle electromyographic activity. However, injecting lidocaine intrathecally or transecting the medial branch of the dorsal ramus had no effect on electromyographic activity. Injecting lidocaine into the facet or into the multifidus muscle around the facet joint (near the stimulating electrode) significantly decreased the magnitude of the multifidus electromyography.CONCLUSION: These results indicate that afferent impulses conveyed by the medial branch of the dorsal ramus reflexly altered efferent activity to an adjacent lumbar segment. This intersegmental paraspinal reflex may span at least one or two vertebral segments. The data suggest that electrical stimulation of the facet joint capsule may not have reflexly elicited multifidus activity because neither chemical interruption (intrathecal lidocaine) nor physical interruption (nerve transection) of the presumed reflex pathway diminished or abolished the electromyographic response. Volume conduction of the stimulating currents likely elicited multifidus activity during electrical stimulation of the facet capsule. When using electrical stimulation of neural paraspinal tissues to evoke reflex muscle activity, appropriate control experiments must be performed to clearly demonstrate the reflexive nature of the response.