Spinal nerve stimulation in S1 radiculopathy

The H reflex plays an important role in electrodiagnosis, but it does not give specific information about any particular segment of its long conduction pathway. Direct stimulation at the S1 spinal nerve might provide more complete information by dividing the H reflex pathway into its peripheral and spinal conduction portions. Patients with electromyographic evidence of S1 radiculopathy (n = 77) and normal control subjects (n = 56) were evaluated. Standard H reflex conduction studies were followed by monopolar needle stimulation of the first sacral spinal nerve. The ratio of the spinal nerve latency to the H reflex latency (S1 ratio) was calculated. The abnormal S1 ratio seen in 77% of the subjects suggested relative slowing within the spinal segment of the nerve. The remainder of the subjects with S1 radiculopathy had slowed conduction also affecting the peripheral segment that could have been caused by Wallerian degeneration. The S1 ratio can provide evidence that H reflex conduction slowing is the result of injury involving the intraspinal nerves. This technique should be especially useful in cases of acute lumbosacral injury when needle electromyographic study is often nondiagnostic.     

Treatment based on H-reflexes testing improves disability status in patients with cervical radiculopathy

BACKGROUND: Postural modification in patients with lumbosacral radiculopathy either causes further H-reflex suppression, indicating increased root compression, or it effects recovery, indicating decompression of the spinal root. The posture that effects maximum recovery of the H-reflex amplitude is called optimum spinal posture (OSP) and is suggested as a therapeutic exercise to decompress the compromised nerve root. The focus of this study was to identify the OSP that effects the maximum recovery of the flexor carpi radialis (FCR) H-reflex and to study its effect on the disability status in patients with cervical radiculopathy. SUBJECTS AND METHODS: Fourteen patients (46 +/- 12 y) with confirmed symptoms of C7 radiculopathy for the previous 6 months volunteered for the study. The FCR H-reflex was elicited by electrical stimulation of the median nerve at the cubital fossa (0.5 ms, 0.2 pps at H-max). Signals from the FCR muscle were recorded using a Cadwell 5200A EMG unit. The FCR H-reflex was recorded in natural sitting position with the head in natural position and in the OSP. Four traces of the H-reflex were recorded and averaged. The disability status was evaluated, using the Neck Disability Index (NDI), before exercising in the OSP and after 2 days of exercise in the OSP. DATA ANALYSIS: Paired t-test and Spearman's correlation coefficients were used. RESULTS: The H-reflex amplitude and latency were significantly different in the OSP and with the head in a natural position (P < 0.004; P < 0.011). Larger reflex amplitude and shorter latency were recorded in the OSP. The NDI scores were considerably improved after exercising in the OSP (P < 0.001). Spearman's correlation coefficient showed negative association between the H-reflex amplitude and the NDI scores (r = -0.64 to -0.54; P < 0.05). CONCLUSION: Exercising in the OSP increased the H-reflex amplitude and decreased latency of the compromised cervical root. It resulted in decreasing the disability status in this group of patients.     

Responses to mechanical stimulation of the upper limb in painful cervical radiculopathy

Clinical and electromyographic (EMG) responses to non-noxious mechanical stimuli were studied in four patients with painful cervical radiculopathy, and in two control subjects. In the symptomatic arm(s), palpation over one or more nerve trunks was painful and accompanied by EMG activity, whereas palpation of adjacent soft tissues was painless and unaccompanied by EMG activity. Electromyographic activity was widespread in three patients when myotatic reflexes were elicited in the symptomatic arm(s). In asymptomatic arms of patients and controls, EMG responses to the myotatic reflexes were more localised. Allodynic nerve trunks in cervical radiculopathy appear to be afferent correlates of central sensitisation; the accompanying EMG activity may represent a motor correlate of this same process.     

干燥综合征伴周围神经病变的临床电生理与病理特点

目的 探究干燥综合征伴周围神经病变的临床电生理与病理特点.方法 以2018年1月至2021年1月收治的50例干燥综合征伴周围神经病变患者为试验组,同时以50例干燥综合征不伴周围神经病变患者为对照组.分析试验组临床电生理以及病理特点,比较两组患者临床表现的差异性.结果 试验组感觉神经传导异常患者中,10.00％为尺神经受...     

Transcranial magnetic stimulation for detection of preclinical cervical spondylotic myelopathy.

Twenty-three patients, mean age 50.4 years, with cervical radiculopathy at C7 or more rostrally, were studied with electromyography, CT scans (in 16 cases) and transcranial magnetic stimulation. None had overt evidence of myelopathy. Motor evoked potentials (MEPs) were recorded from the hand muscles (C8/T1), and latency, amplitude, and the MEP/CMAP ratio and central motor delay between the hand motor cortex and the lower cervical spine were measured. One or more of these were abnormal in 15 of 23 cases (65%). The most common abnormality was a reduced MEP/CMAP ratio. The findings indicate that physiologic dysfunction of the spinal cord, caudal to a radiculopathy, frequently accompanies a radiculopathy and may antedate overt cervical spondylotic myelopathy. This may be valuable in directing more timely surgical intervention.     

腕管综合征的电生理分析及与身体质量指数的相关性

目的:探讨88例腕管综合征(CTS)的电生理特点,明确电生理检查的诊断价值。方法:对88例门诊腕管综合征患者行一侧或双侧正中神经、尺神经的分段运动神经传导速度(MCV)和,Ⅰ、Ⅴ、Ⅳ指刺激感觉神经传导速度(SCV)测定,以及拇短展肌针极肌电图检查;计算每一位患者身体质量指数(BMI)及正中神经与尺神经Ⅳ指刺激感觉神经动作电位(SNAP)波幅比值。结果:Ⅰ、Ⅳ指刺激正中神经SNAP潜伏期延长者的百分比分别为59.1%与65.9%;复合肌肉动作电位(CMAP)波幅降低者中拇短展肌肌电图异常者占87.2%;SNAP各参数正常者中有8例(72.7%)出现Ⅳ指刺激正中神经与尺神经波幅比值的异常,各异常参数患者BMI值无显著性差异。结论:神经电生理检查是诊断CTS的理想检测手段。     

Somatosensory evoked potentials from dermatomal stimulation as an indicator of L5 and S1 radiculopathy

Dermatomal somatosensory evoked potential (DSEP) results for L5 and S1 were contrasted with electromyography (EMG) results for 50 patients referred to the electrodiagnosis laboratory to document the presence of radiculopathy. Stimulation sites were over the dorsum of the foot at the distal fifth metatarsal for the S1 dermatome and at the web space of the first and second toe for the L5 dermatome. Recordings were made at PZ reference to FZ. Spinal cord or cauda responses could not be detected. Both EMG and DSEP were contrasted to myelography or lumbar computerized tomography results on 31 patients. Side-to-side amplitude differences proved too variable to be of use. Sixty-five percent of abnormal DSEP results were on the basis of side-to-side latency criterion, and 35% were on the basis of an absent unilateral response. When compared to EMG and anatomic studies DSEP showed less accuracy and sensitivity. The specificity of the two tests was similar. Using both positive EMG and anatomic studies to define radiculopathy, there were 27% false negative tests and 9% false positive tests. An 86% root level correlation was found between EMG and DSEP. Dermatomal somatosensory evoked potential studies add little to the diagnosis of radiculopathy.     

Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring

Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. In twenty patients who underwent thoracic and/or lumbar spinal surgery with TcMEP monitoring, the triple stimulation technique (TST) was applied to the unilateral upper arm intraoperatively. Total intravenous anesthesia was employed. Trains of four stimuli were delivered with maximal intensity and an inter-pulse interval of 1.5 ms. TST responses were recorded from the abductor digiti minimi muscle, and the negative peak amplitude and area were measured and compared between the TST test (two collisions between transcranial and proximal and distal peripheral stimulation) and control response (two collisions between two proximal and one distal peripheral stimulation). The highest degree of superimposition of the TST test and control responses was chosen from several trials per patient. The average ratios (test:control) were 17.1 % (range 1.8–38 %) for the amplitudes and 21.6 % (range 2.9–40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.     

The use of electromyography to predict functional outcome following transforaminal epidural spinal injections for lumbar radiculopathy.

This study aimed to determine if electromyographic (EMG) diagnostic evaluation can predict functional outcome in patients undergoing transforaminal lumbar spine epidural injections. In this retrospective study, functional outcome by Oswestry Disability Index (ODI) and verbal rating scale (VRS) for current pain severity was evaluated in 39 patients undergoing lumbar transforaminal epidural spinal injections (ESI). Subjects with low back pain (mean age, 60 +/- 12.5 years) were evaluated for functional improvement post EMG and ESI. Of 39 patients tested with EMG before injection, 18 patients were positive for radiculopathy and 21 had a normal or negative examination. The patients were followed postinjection on average of 10.8 (SD +/- 3.9) weeks. Pretreatment ODI scores were not significantly different between groups showing positive (72.3 SD +/- 12.7) and negative (65.9 SD +/- 18.6, P > .05) EMG findings. There was significantly greater improvement of ODI for EMG positive radiculopathy (7.11 SD +/- 9.5) compared with negative EMG (3.2 SD +/- 17.4, P < .05). Positive radiculopathy subjects complained of more pain by VRS before ESI than subjects with negative EMG findings, 8.1 SD +/- 1.0 and 7.3 SD +/- 0.8, respectively, which was not significant (P > .05). VRS mean improvement was not significantly different in the positive EMG group (1.8 SD +/- 1.2) compared with a negative EMG (1.2 SD +/- 1.2, P > .05). PERSPECTIVE: The results appear to show that patients undergoing transforaminal ESI, who have a positive radiculopathy by EMG before injection, will have significant improvement in functional outcome by ODI but not with current pain intensity by VRS. This study suggests the importance and diagnostic value of ordering electromyography studies for lumbar radiculopathy evaluation, which may lead to prediction of outcome with lumbar transforaminal epidural spinal procedures. Furthermore, the current study highlights the difficulty of pain evaluation outcome by VRS.     

小儿坐骨神经注射性麻痹的肌电图观察

背景肌电图检测是确诊注射性坐骨神经损伤重要方法之一,但其早期异常表现,异常程度与病程的相关性及各项指标的差异比较尚缺乏深入研究.目的探讨注射性坐骨神经损伤的电生理特点.设计以诊断为依据临床观察分析.地点和对象104例南京医科大学附属脑科医院门诊确诊患儿,年龄4个月～14岁,病前均有明确臀部肌肉注射史,既往无其他神经肌肉疾病.干预应用丹迪Neuromatic 2000 M型肌电仪检测患儿的患肢肌电图.主要观察指标检测患儿的患肢腓总神经和胫神经/胫后神经的感觉传导速度(sensory conduction velocity,SCV)、运动传导速度(motor conduction velocity,MCV)、末端运动潜伏期(distal motor latency,dML)和末端复合肌肉动作电位波幅(distal compound muscle action potential amplitude,dCMAPA)、感觉神经动作电位波幅(sensory nerve action potential ampli-tude,SNAPA);同时检测坐骨神经支配肌的针极肌电图.结果肌注后2～7 d已可检出多项电生理异常.腓总神经支的神经传导速度(nerve conduction velocity,NCV)异常率(68.0%)明显高于胫神经支(43.5%)(x2=12.199,P＜0.005).腓总神经SCV,SNAPA和dML,dCMAPA异常程度与病程正相关(r=0.306 8,P＜0.005;r=0.296 3,P＜0.005;r=0.337 6,P＜0.001;r=0.215 7,P＜0.05).8个月以上病程患儿的SCV, SNAPA和dML异常程度明显增加(F=3.105,P＜0.05;F=4.095,P＜0.01;F=5.904,P＜0.01),较8个月内有显著差异.腓总神经NCV各项配对t检验发现运动纤维dML和dCMAPA异常程度重于感觉纤维SCV和SNAPA(t=2.070,P＜0.05;t=3.520,P＜0.001).结论化学药物对神经髓鞘传导功能有直接损伤.坐骨神经运动纤维的电生理异常早于且重于感觉纤维.腓总神经运动传导功能检测是本病早期诊断的重要依据.8个月以上病程的损伤神经恢复难度增加.     

深层椎旁肌肌电图在脊神经根受损中的定位价值

目的 探索脊神经受损定位诊断中的精确定位检测指标。方法 对200例脊神经根受损患者先行传统定位检查,在此基础上,根据肢体异常肌 群的对照检查。结果 200例473块患侧椎帝肌100％阳性,健侧10块对照肌100％阴性。凡肢体异常肌群呈根性分布均在相应深层椎旁肌上得到了阳性验证,其中18例轻症仅表现为患侧53块椎旁肌阳性和4个H反身的延长,而无其他指标的改变。结论 深层椎旁肌肌电图的阳性改变在脊神经根受损的诊断中是一个最早出现的精确定位检测指标,具有极 敏感性和特异性。     

下胸段脊旁肌肌电图在运动神经元病诊断中的应用

目的探讨下胸段脊旁肌肌电图在诊断运动神经元病(MND)中的价值。方法共检查3组受试者，即A组为102例确诊的MND患者行常规上下肢肌肉、下胸段脊旁肌和胸锁乳突肌肌电图检测；B组为性别、年龄相匹配的96例颈腰脊神经根损害患者，行常规上下肢肌肉、下胸段脊旁肌肌电图检测；C组为性别、年龄相匹配的100名健康人．行常规上下肢肌肉、下胸段脊旁肌肌电图检测。结果102例MND患者中，87例(85．3％)下胸段脊旁肌肌电图可见大量纤颤电位和正锐波，94例(92．1％)胸锁乳突肌肌电图运动单位时限增宽、波幅增高。96例颈腰脊神经根损害的患者中，6例(6．2％)下胸段脊旁肌肌电图可见少量自发电位。100名健康人下胸段脊旁肌肌电图未见异常。结论下胸段脊旁肌肌电图有助于MND的诊断。     

Sensorimotor integration in Complex Regional Pain Syndrome: a transcranial magnetic stimulation study

There is evidence that patients with Complex Regional Pain Syndrome (CRPS) have altered central sensorimotor processing. Sensory input can influence motor output either through indirect pathways or through direct connections from the sensory to motor cortex. The purpose of this study was to investigate sensorimotor interaction via direct connections in patients with CRPS and to compare the results with normal subjects'. Direct short-latency sensory-motor interaction was evaluated in eight patients with CRPS1 affecting a hand. Modulation of EMG responses to transcranial magnetic stimulation (TMS) induced by concomitant median nerve stimulation was measured, the so-called, short-latency afferent inhibition (SAI). Results were compared with eight normal subjects who were age and sex matched with the patients. As expected, all the normal subjects' EMG responses to TMS with median nerve stimulation were smaller than responses to TMS alone. In seven of the eight CRPS patients EMG responses to TMS were suppressed when paired with median nerve stimulation. Only one CRPS patient's results showed no suppression of EMG responses. These results suggest that the disease mechanisms of CRPS1 do not typically affect the direct neural circuit between sensory and motor cortex and that normal sensorimotor interaction is occurring via this route.     

Subclinical neuromuscular transmission abnormality detected by single-fibre EMG is more pronounced in cluster headache than in migraine with aura

The aim was to investigate neuromuscular transmission (NMT) by single-fibre EMG (SFEMG) in a large series of patients having migraine with aura (MA) or cluster headache (CH). Recent studies using SFEMG have shown subclinical dysfunction of NMT in MA and CH. Forty-three patients having MA, 51 with CH and 38 healthy control subjects underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Twenty different potential pairs were recorded and individual, mean and total abnormal individual jitter values were calculated. The results obtained from MA patients were compared with those from CH patients. In MA patients, 32 of 860 jitters were abnormally high, whereas 73 of 1020 of the jitters showed this abnormality in CH patients. None of the control subjects, five MA patients (11.6%) and 11 CH patients (21.6%) were designated as having subclinical NMT abnormality. Thus, patients having junction dysfunction were significantly more common in the CH group. The subclinical NMT abnormality shown by SFEMG is more common in CH than in MA. These two primary headache syndromes may have some shared functional abnormality of NMT constituents which is more evident in CH.     

经尿道膀胱肿瘤电切术中闭孔神经反射的临床研究

目的探讨利用针形电极诱发神经反射、弧形切割并结合肿瘤基底部闭孔神经阻滞在经尿道膀胱肿瘤电切术（TURBT）中预防闭孔神经反射的效果。方法 2008年4月至2010年10月,82例膀胱肿瘤患者在椎管麻醉下行TURBT,对针形电极弧形切割诱发的闭孔神经反射采用肿瘤基底部闭孔神经阻滞。结果术中针形电极诱发闭孔神经反射27例,通过肿瘤基底部深肌层水平方向浸润注射利多卡因后闭孔神经反射消失。27例均顺利完成手术,未发现膀胱壁破裂、严重出血等并发症。结论针形电极弧形切割结合肿瘤基底部闭孔神经阻滞可有效预防TURBT术中闭孔神经反射,降低膀胱穿孔及严重出血的发生率。该方法简便易行,具有一定临床应用价值。     

The effects of isoflurane and propofol on intraoperative neurophysiological monitoring during spinal surgery

Objectives. To compare the effects of isoflurane and propofol on intraoperative neurophysiological monitoring (IONM) during spinal surgery. Methods. Thirty-five patients were randomly assigned to receive isoflurane (n = 17) or propofol (n = 18) anesthesia. Somatosensory evoked potentials (SEPs) following posterior tibial nerve stimulation were recorded before induction as baselines. Isoflurane concentrations and propofol infusions were adjusted to obtain four pre-determined BIS ranges: 65–55, 55–45, 45–35 and 35–25. For each range, a stable state was maintained for at least 10 min to perform IONM. The SEP latency P40 and amplitude P40-N50, the onset latency and amplitude of transcranial motor evoked potentials (tcMEPs), and threshold intensity of triggered electromyographic activity (EMG) following pedicle screw stimulation were statistically analyzed. Results. Compared with baseline values, P40 latency increased and P40-N50 amplitude decreased after anesthesia with isoflurane or propofol. Isoflurane caused a dose-dependent depression of SEPs, but propofol did not. TcMEPs were recordable and stable in all patients receiving propofol in each BIS range, but only recordable in 10 (58.8%) receiving isoflurane with BIS > 55, and 3 (17.8%) with BIS < 55. No difference was noted in triggered EMG. Conclusions. Isoflurane inhibited IONM more than propofol. Propofol is recommended for critical spinal surgery, particularly when motor pathway function is monitored. Chen Z, The effects of isoflurane and propofol on intraoperative neurophysiological monitoring during spinal surgery     

Relief of experimental spasticity and anxiolytic/anticonvulsant actions of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline.

Spasticity is characterized by pathological overactivity in spinal stretch reflex circuits and may be associated with disturbances in excitatory amino acid-mediated transmission in the cord. A genetically determined syndrome of spasticity in the rat permits the quantitative evaluation of the antispastic effects of drugs by recording activity in the electromyogram (EMG) from a hind limb extensor muscle. In genetically spastic rats, systemic administration of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) antagonist, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F) quinoxaline (NBQX), normalized pathologically increased EMG activity, whereas the AMPA agonist, alpha-amino-3-hydroxy-5-tertbutyl-4-isoxazolepropionate (ATPA), exacerbated the EMG measures of spasticity. The reflex mechanisms in the spinal cord can be studied in mice using EMG recordings from the tibial muscle (Hoffmann reflex) or from the plantar foot muscle (flexor reflex) after electrical stimulation of the tibial nerve. Systemic and i.t. administration of NBQX blocked Hoffmann reflexes in mice, leaving flexor reflexes unchanged. ATPA enhanced Hoffmann, and had no effect on flexor reflexes. The effects of NBQX on spinal reflexes were seen in doses which do not affect locomotor activity, but show anxiolytic and some antiepileptic activity in rodents. These data suggest that the design of novel muscle relaxant drugs acting at the AMPA subtype of glutamate receptors may be feasible.     

Peripheral effects of needle stimulation (acupuncture) on skin and muscle blood flow in fibromyalgia.

Acupuncture has become a widely used treatment modality in various musculoskeletal pain conditions. Acupuncture is also shown to enhance blood flow and recovery in surgical flaps. The mechanisms behind the effect on blood flow were suggested to rely on vasoactive substances, such as calcitonin gene-related peptide, released from nociceptors by the needle stimulation. In a previous study on healthy subjects, one needle stimulation into the anterior tibial muscle was shown to increase both skin and muscle blood flow. The aim of this study was to examine the effect of needle stimulation on local blood flow in the anterior tibial muscle and overlying skin in patients suffering from a widespread chronic pain condition. Fifteen patients with fibromyalgia (FM) participated in the study. Two modes of needling, deep muscle stimulation and subcutaneous needle insertion were performed at the upper anterior aspect of the tibia, i.e., in an area without focal pathology or ongoing pain in these patients. Blood flow changes were assessed non-invasively by photoplethysmography (PPG). The results of the present study were partly similar to those earlier found at a corresponding site in healthy female subjects, i.e., deep muscle stimulation resulted in larger increase in skin blood flow (mean (SE)): 62.4% (13.0) and muscle blood flow: 93.1% (18.6), compared to baseline, than did subcutaneous insertion (mean (SE) skin blood flow increase: 26.4% (6.2); muscle blood flow increase: 46.1% (10.2)). However, in FM patients subcutaneous needle insertion was followed by a significant increase in both skin and muscle blood flow, in contrast to findings in healthy subjects where no significant blood flow increase was found following the subcutaneous needling. The different results of subcutaneous needling between the groups (skin blood flow: p=0.008; muscle blood flow: p=0.027) may be related to a greater sensitivity to pain and other somatosensory input in FM.     

The effect of low-frequency electrical stimulation on denervation atrophy in man

The effect of low frequency electrical stimulation (LES) on denervation atrophy and recovery of the muscles was examined in a group of 73 patients with a single or a combined total lesion of the median, ulnar or peroneal nerves. The differences between the patients were evaluated by means of clinical muscle force testing, EMG, dynamometry (ulnar and median nerve lesions), computer tomography (ulnar nerve lesions) and ultrasonography (median and peroneal nerve lesions). A beneficial effect of LES could not be shown.     

肌张力低下型脑性瘫痪与婴儿脊髓性肌萎缩的对比研究

目的对比分析脑性瘫痪(CP)肌张力低下型和婴儿脊髓性肌萎缩(SMAⅠ型)的临床、神经电生理和影像学特点,加深临床医师对两种疾病的认识,避免误诊、误治。方法对21例脑性瘫痪肌张力低下型及11例SMAⅠ型患儿的临床、神经电生理、头颅影像学进行回顾性对比分析,并对部分患儿进行随访。结果 CP患儿围生期异常率较SMAⅠ型患儿高,肌无力常较轻微且随年龄增长而好转,肌张力降低轻于SMAⅠ型患儿且腱反射可以引出,病理征可以阳性,部分患儿伴有认知功能障碍及癫痫;CP患儿可伴有脑电图(EEG)及头颅MRI/CT异常,神经传导功能检测及肌电图(EMG)正常;而SMAⅠ型患儿神经传导功能检测及EMG异常。15例CP患儿随年龄增长而有所好转,7例SMAⅠ型患儿病情恶化,4例已死亡。结论围生期病史询问、体格检查及EEG、MRI/CT、运动神经传导速度(MCV)、EMG检查有助于CP、SMAⅠ型的鉴别诊断,远期预后差异显著。