Diagnostic and prognostic value of compound motor action potential of lower limbs in acute paraplegic patients

OBJECTIVES: To evaluate the diagnostic and prognostic contribution of motor nerve conduction studies (NCS) in addition to neurological examination in patients with acute paraplegia. METHODS: In 79 patients with acute onset of paraplegia due to traumatic or ischaemic damage of the conus medullaris/cauda equina (conus/cauda) or lesion of the mid-thoracic spinal cord (epiconal) neurological (initial and follow-up clinical motor and sensory scores; outcome of ambulatory capacity determined at least 6 months post-trauma) and electrophysiological examinations (motor nerve conduction velocity (MNCV) and compound motor action potential (CMAP) of tibial and peroneal nerves) were performed in parallel. RESULTS: Severe axonal motor neuropathies were significantly caused by conus/cauda lesions (loss of tibial CMAP in 71% and of peroneal CMAP in 68%) compared to patients with epiconal lesion (no loss of tibial CMAP and abolished peroneal CMAP in 14%). The CMAPs were deemed acutely pathological 4 - 14 days post-trauma and were indicative of the severity of conus/cauda lesion while the MNCV remained normal. Follow-up recordings (up to 1 year post trauma) revealed no significant change in the CMAP values. The clinical examination according to the American Spinal Injury Association (ASIA protocol) in contrast to the CMAP values was significantly related to the outcome of ambulatory capacity. CONCLUSIONS: In contrast to patients with an epiconal SCI almost all patients with damage of the conus/cauda present a severe axonal neuropathy of the tibial and peroneal nerves. Pathological CMAPs develop as early as 1 - 2 weeks after onset of acute paraplegia. They allow, at an early stage, to differentiate between conus/cauda or epiconal lesion and to assess the severity of conus/cauda lesion. Thereafter follow-up examinations remain stable and a developing worsening of peripheral nerve or spinal cord function, eg due to post-traumatic syringomyelia, may be indicated by a secondary deterioration of CMAP values. The clinical examination, according to the ASIA protocol, in acute paraplegia patients, in contrast to the motor nerve conduction studies, is of prognostic value in predicting the outcome of ambulatory capacity.     

肌电图-神经电图测定健侧颈_7神经根移位桥接至受体神经后再生的临床研究

目的　用肌电图 -神经电图检测方法 ,研究健侧颈 7神经根移位通过桥接至受体神经后再生的状况。方法　 1996年 3月至 1998年 9月 ,对 2 8例健侧颈 7移位二期手术后患者 ,定期进行肌电图 -神经电图随访。术后随访时间为 3～ 5 8个月 ,平均 15 .4个月。分别在胸锁关节、胸腋部、腋部、肘部或外侧肌间隔刺激受体神经 (肌皮神经、桡神经和正中神经 ) ,于该神经支配的相应肌肉上记录复合肌肉动作电位 (CMAP) ,测定其潜伏期 (L at)、波幅 (Amp)。计算出动力神经纤维在受体神经的运动传导速度(MNCV) ,并观察其肌电图表现。结果　患侧桡、肌皮和正中神经支配的相应肌肉 ,分别在术后 4、6和 12个月时检测到神经再生电位。结论　健侧颈7神经根移位后 ,受体神经中出现再生电位最早的为肌皮神经 ,桡神经次之 ,正中神经最晚     

Electrophysiological abnormalities in upper extremities after brachiocephalic A-V fistulas construction in predialysis patients

BACKGROUND: Peripheral neuropathy is considered a common complication in patients suffering from advanced chronic kidney disease (CKD). Superimposed peripheral multiple neuropathies may complicate arteriovenous (A-V) fistulas construction. AIM: To evaluate, prospectively, the influence of brachiocephalic A-V fistulas construction on the peripheral nerves of the same extremity and to characterize the patients at risk for developing ischemic and neurological complications. PATIENTS AND METHODS: Twenty patients suffering from advanced CKD were enrolled in the study: 10 diabetic and 10 non-diabetic patients. All patients underwent electrophysiological evaluation one week before, 3 weeks and 3 months after surgery. Median, ulnar and radial nerves were studied. RESULTS: In non-diabetic patients MNCV was normal before and after surgery, but were significantly lower and reduced progressively and significantly after surgery in diabetic patients (p< or =0.02). In both non-diabetic and diabetic patients SNCV was reduced, but were significantly lower in diabetic patients before and after surgery (p< or =0.03). In diabetic patients it reduced progressively and significantly after surgery (p<0.01). Thirty percent of patients developed local edema and significant decrease of CMAP of median nerve three weeks after surgery (p=0.02) with complete resolution at three months. CONCLUSION: Diabetic uremic patients are at increased risk to develop disabling neurological complications after the construction of A-V fistulas. Diabetes was the only predictive risk factor for developing these complications. Prevention requires careful preoperative electrophysiological evaluation and postoperative follow-up.     

Diagnostic utility of waveform analysis of compound muscle action potentials for carpal tunnel syndrome

PURPOSE: To determine the diagnostic utility of waveform analysis of compound muscle action potentials (CMAP) for carpal tunnel syndrome (CTS). METHODS: A total of 131 hands in 71 patients diagnosed with CTS (grouped according to severity) and 80 hands in 44 normal subjects were evaluated using nerve conduction test through the carpal tunnel combined with waveform analysis of CMAP. RESULTS: Compared to normal subjects, the sensory nerve conduction velocity and mean frequency of the CMAP waveform were significantly reduced in patients with CTS. Compared with distal motor latency and sensory nerve conduction velocity, the mean frequency of the CMAP decreased significantly with increasing clinical severity. CONCLUSION: This study suggests that waveform analysis of CMAP is of diagnostic value in CTS, and is also of value in objective evaluation of postoperative recovery of carpal median nerve dysfunction.     

An experimental study on compression neuropathy--the effect of neurolysis on the blood-nerve barrier]

The effects of neurolysis on the sciatic nerves of normal controls and in dogs with compression neuropathy were evaluated by macroscopic and electrophysiological studies. The function of the blood-nerve barrier (BNB) was also assessed by Evans blue albumin. Studies on normal sciatic nerves (normal controls): In the epineurectomy group, neither scars nor denervation potentials were recognized. Moreover, the motor nerve conduction velocity (MNCV) and BNB were found to remain normal. In the perineurotomy group, on the other hand, scar formation at the surrounding tissue and denervation potentials were evident. BNB function was impaired and persisted for at least eight weeks. Studies on the compression neuropathy model: MNCV was increased in both the external neurolysis group and the epineurectomy group, and BNB function required six weeks to recover. MNCV was increased in the perineurotomy group, adhesion was severe, and denervation potentials and impairment of the BNB continued. In conclusion, both external neurolysis and epineurectomy restore the function of compressed nerves. There is no significant difference between these methods. Perineurotomy is not considered an appropriate technique for managing compression neuropathy.     

The effects of intrathecal tramadol on spinal somatosensory-evoked potentials and motor-evoked responses in rats

Tramadol has been proven to exert a local anesthetic-type effect on peripheral nerves in both clinical and laboratory studies. In this study, we evaluated the effects of tramadol on sensory and motor neural conduction when administered intrathecally in the rat. Tramadol (0, 1, or 2 mg) was administered through an intrathecal catheter. Spinal somatosensory-evoked potentials (SSEPs) were recorded at the thoracolumbar junction after stimulation of the sciatic nerve. An evoked compound muscle action potential (CMAP) was recorded in the intrinsic muscles of the foot in response to electric stimulation of the lower thoracic (T1213) interspinous space. Both SSEP and CMAP were obtained before drug application as the pretreatment baseline and at 5, 15, and 30 min after treatment, and at 30- or 60-min intervals thereafter for another 4.5 h. SSEP was averaged from 20 responses, whereas CMAP was obtained from a single stimulation. Reproducible SSEPs and CMAP were consistently recorded in all rats. Intrathecal tramadol dose-dependently reduced the amplitude and delayed the latency in both SSEPs and CMAP. Generally, the suppressive effects occurred immediately after injection and recovered over 2 h. Combined administration with 20 micro g of intrathecal naloxone did not attenuate the inhibition of spinal SSEPs. We conclude that intrathecal tramadol causes a dose-related suppressive effect on both sensory and motor neural conduction in the spinal cord. IMPLICATIONS: Spinal somatosensory-evoked potentials and evoked compound muscle action potential were used to evaluate the effects of intrathecal tramadol on sensory and motor neural conduction. Intrathecal tramadol dose-dependently reduced the amplitude and delayed the latency of both spinal somatosensory-evoked potentials and compound muscle action potential. These results indicate that tramadol exerts a dose-related central neural blockade.     

Peripheral neuropathy in HIV patients: treatment by decompression of peripheral nerves

Peripheral neuropathy is the most common nerve disorder in human immunodeficiency virus (HIV) patients. Distal symmetrical sensory polyneuropathy (DSP) affects roughly one third of HIV patients. With the introduction of antiretrovirals, more patients are surviving longer, and chronic complications are surfacing. Three consecutive patients with at least a 5-year history of HIV presented during the period from 2007 to 2009. All three patients were on antiretrovirals and had no other comorbid conditions such as spinal pathology or diabetes. All patients had symptoms of pain, numbness, and weakness. Quantitative sensory testing and/or electromyography/nerve conduction testing (EMG/NCT) were performed preoperatively and correlated with the presence of Tinel signs. Targeted nerve releases were performed in four extremities, for a total of 18 nerves. All three patients had symptomatic improvement at 1 year with a visual analog scale (VAS) reduction in pain by at least five points. Quantitative sensory testing showed improvement, as did two EMG/NCTs obtained postoperatively. This showed improvement in conduction velocity at the fibular tunnel and posterior tibial nerve at the tarsal tunnel. This is the first report of nerve decompressions in the lower and upper extremity of HIV patients in the literature outside of the median nerve in the carpal tunnel.     

Evaluation of spectrum of peripheral neuropathy in predialysis patients with chronic kidney disease

Abstract

Introduction: Neurological complications secondary to the uremic state, contribute largely to the morbidity and mortality in patients with renal failure. The prevalence of peripheral neuropathy remains high in advanced renal dysfunction. Materials and methods: The present cross-sectional study was conducted on 100 adult patients of chronic kidney disease between 18 and 75 years of age with serum creatinine greater than 2?mg/dL. Apart from routine examination and baseline investigations, detailed history was elicited pertaining to patients’ neurological symptoms, and scored according to the Neurological Symptom Score. Motor nerve conduction velocity was measured from right median, ulnar, peroneal, and tibial nerves. Results: It was observed that neurological symptoms increased steadily with raise in serum creatinine. The mean nerve conduction velocities (NCVs) of right median nerve, ulnar nerve, peroneal nerve, and tibial nerve were 51.34?±?6.07, 53.04?±?5.91, 44.72?±?6.14, and 44.20?±?5.17, respectively. The NCVs of all the tested nerves decreased significantly with increase in serum creatinine levels (p?<?0.01): 70% of the patients had uremic polyneuropathy; 6% had asymptomatic neuropathy, 51% had symptomatic non-disabling neuropathy, while disabling neuropathy was seen in 13% of the patients. Conclusion: Our data suggests that NCV testing when complimented with meticulous neurological assessment can provide invaluable input. These tests apart from helping us detect neuropathy in advanced renal dysfunction; can also detect the disease in largely asymptomatic patients which avoids the necessity to order for detailed neurophysiological investigation     

兔坐骨神经高压电损伤后早期电生理改变的实验研究

目的 研究家兔坐骨神经高压电损伤后早期电生理的变化规律。方法 新西兰家兔48只,分成2组。实验组40只,以1万V高压电电击右下肢,于伤后即刻、3、7、14、21d共5个时间组检测实验兔右下肢的肌电图（EMG）、运动神经传导速度（MNCV）、复合肌肉电位（CMAP）和皮层体诱发电位（SEP）。正常对照组8只家兔不作任何处理。结果 20只兔右侧坐骨神经的MNCV、CMAP、SEP在伤后3d全部测不出,提示为完全损伤。20只兔随伤后时间的推移,坐骨神经的MNCV逐渐减慢;CMAP和SEP的潜伏期逐渐延长,波幅逐渐降低。提示为不全损伤。两者肌电图失神经电位的变化则相似。结论 家兔坐骨神经被高压电击伤后早期的肌电图神经电图改变呈进行性加重。     

Power spectrum analysis of compound muscle action potential in carpal tunnel syndrome patients

The objective of using wave-form analysis to assess compound muscle action potential (CMAP) in entrapment neuropathy had not been fully developed. We applied the power spectrum analysis to patients with carpal tunnel syndrome (CTS) for this purpose. 24 patients with CTS were divided into three stages according to Mackinnon s classification, and 50 normal volunteers were examined. CMAP was obtained from the abductor pollicis brevis with supramaximal stimulation to median nerve. Mean and peak frequencies were measured by power spectrum analysis. The distal latencies of CMAP and the sensory nerve conduction velocities showed some prolongation in CTS patients. Integral values of CMAP were also decreased in CTS patients. Mean and peak frequencies of power spectrum of CMAP in volunteers were 134 Hz and 98 Hz, respectively. These values shifted into lower frequencies in CTS patients, namely 102 Hz and 61 Hz. Regardless of clinical stage, distal latency of CTS patients correlated with mean frequency.     

切断小斜角肌后臂丛神经功能改变的临床观察

目的 :观测小斜角肌在TOS患者术中的出现情况 ,分析切断小斜角肌的临床意义。方法 :回顾性分析下干型TOS共 3 3例 ,手术中探查切断小斜角肌 ,其中 4例进行术中肌电的监测 ,比较术前、切断前中斜角肌后、切断小斜角肌后上臂近段尺神经MNCV ,前臂内侧皮神经SNAP和尺神经F反应的变化。结果 :术中探查 3 3例下干型TOS中均有小斜角肌的存在 ,术后优良率为 78 8%。切断前中斜角肌后、切断小斜角肌后 ,上臂近段MNCV ,前臂内侧皮神经SNAP和尺神经F反应均较术前有改善。结论 :小斜角肌在绝大多数下干型TOS患者中均有出现 ;切断小斜角肌后下干型TOS患者臂丛神经功能的改善较明显 ;手术治疗中须探查松解小斜角肌     

Enhancement of motor nerve regeneration by nerve growth factor.

The sciatic nerves of adult Wistar rats were severed bilaterally. Each nerve was sutured into a silicone tube used as a conduit, leaving a 5 mm gap in length between the nerve ends. Nerve growth factor in a saline solution vehicle was injected into the silicone chamber on the right side and normal saline solution (control) on the left. Six weeks after surgery, electrophysiological studies were performed. The motor nerve conduction velocities (MNCV) were significantly increased in the NGF-treated nerves. In one rat, the MNCV on the NGF-treated side was 66.6 m/s, in the range of normal nerves. There was no significant difference between the two sides in the amplitudes of evoked muscle action potentials. There are apparently no reports on the effect of NGF on motor neuron regeneration in vitro. In this study, NGF was found to enhance motor nerve regeneration.     

Touch pressure and sensory density after tarsal tunnel release in diabetic neuropathy

BackgroundLimited quantitative information is available about the improvement of protective sensation after tarsal tunnel release in patients with diabetic peripheral neuropathy.MethodsProspective, non-blinded, non-randomized case series of 10 feet in 8 diabetic patients and 24 feet in 22 non-diabetic patients who had tarsal tunnel release. Preoperative and postoperative (average, 8–9 months) anatomic, quantitative sensory testing was done with touch pressure 1-point threshold (Semmes–Weinstein monofilaments) and 2-point discrimination.ResultsThere was marked, significant postoperative improvement of mean touch pressure 1-point threshold, compared with preoperative values, for medial calcaneal, medial plantar, and lateral plantar nerves in both non-diabetic and diabetic patients. There was minimal improvement in 2-point discrimination only for the medial calcaneal nerve in non-diabetic, but not in diabetic, patients.ConclusionsNerve entrapment at the tarsal tunnel is an important component of diabetic peripheral neuropathy. Tarsal tunnel decompression may improve sensory impairment and restore protective sensation.     

Perineural meperidine blocks nerve conduction in a dose-related manner: a randomized double-blind study

Background: Meperidine has been shown to exhibit a sensory block in peripheral nerves. However, its motor blockade ability is controversial. The aim of this study was to investigate, electroneurographically, the ability of meperidine to inhibit conduction in both sensory and motor fibres in the ulnar nerve.
Materials and methods: The study was conducted in a double-blind, placebo-controlled fashion. Eighteen healthy volunteers were randomized into three groups (Saline, meperidine 1% and meperidine 2%). Three millilitre of the study solution was administered to the ulnar nerve perineurally at the level of the wrist by the guidance of a nerve stimulator. Sensory nerve action potential (SNAP) and compound motor action potential (CMAP) amplitudes were recorded. At least a 20% decrease in the initial response amplitude was accepted as a block.
Results: The number of individuals with sensory and motor block with saline, meperidine 1% and meperidine 2% were 0/6, 6/6, 6/6 and 0/6, 5/6, 6/6, respectively ( P <0.05). The maximum decrease in the median SNAP and CMAP amplitude values were 4.7% and 8.3% with saline; 38.5% and 46.4% with meperidine 1%; and 100% and 97.8% with meperidine 2%, respectively ( P <0.05). Median values for the duration of sensory and motor block with meperidine 1% and meperidine 2% were 45, 52.5 and 30, 32.5 min, respectively.
Conclusion: Meperidine blocks sensory and motor nerve conduction in a dose-related manner.     

联合使用ATP和NGF对周围神经再生作用的实验研究

目的 研究三磷酸腺苷(adenosine tri-phosphate，ATP)和神经生长因子(nerve growth factor，NGF)联合使用时对受损周围神经再生的作用并比较两者作用的强弱。方法 将64只SD大鼠左侧坐骨神经切断后直接作端端缝合，缝合段置于硅胶管室内。根据室内注入药物的不同，分为生理盐水(NS)、ATP、NGF、和ATP加NGF4组，每组16只大鼠。术后4周和8周(每组均为8只)取标本，作形态学，肌湿重，运动神经传导速度(MNCV)、复合运动动作电位(CMAP)波幅，及组织学的检测。结果 ATP加NGF组的神经纤维数目、大小、髓鞘厚度和MNCV、CMAP及肌湿重均优于其它3个组。NGF组的各项指标比ATP组好。结论联合使用ATP和NGF时受损周围神经的再生作用明显增强。NGF的作用强于ATP。     

Effects of basic fibroblast growth factor on experimental diabetic neuropathy in rats

Basic fibroblast growth factor (bFGF) stimulates angiogenesis and induces neural cell regeneration. We investigated the effects of bFGF on diabetic neuropathy in streptozotocin-induced diabetic rats. Diabetic rats were treated with human recombinant bFGF as follows: 1) intravenous administration, 2) intramuscular injection into thigh and soleus muscles with cross-linked gelatin hydrogel (CGH), and 3) intramuscular injection with saline. Ten or 30 days later, the motor nerve conduction velocity (MNCV) of the sciatic-tibial and caudal nerves, sensitivity to mechanical stimuli, sciatic nerve blood flow (SNBF), and retinal blood flow (RBF) were measured. Delayed MNCV in the sciatic-tibial and caudal nerves, hypoalgesia, and reduced SNBF in diabetic rats were all ameliorated by intravenous administration of bFGF after 10, but not 30, days. Intramuscular injection of bFGF with CGH also improved sciatic-tibial MNCV, hypoalgesia, and SNBF after 10 and 30 days, but caudal MNCV was not improved. However, intramuscular injection of bFGF with saline had no significant effects. bFGF did not significantly alter RBF in either normal or diabetic rats. These observations suggest that bFGF could have therapeutic value for diabetic neuropathy and that CGH could play important roles as a carrier of bFGF.     

臂丛根性损伤两种神经电图—肌电图检测方法的诊断符合率

目的比较两种神经电图－肌电图检测方法对臂丛根性损伤的诊断符合率。方法１９９７年前，对８２例臂丛根性损伤用上肢五大神经代表肌肉及肩胛带肌群肌电图（ＥＭＧ）、复合肌肉动作电位（ＣＭＡＰ）、运动神经传导速度（ＭＮＣＶ）、感觉神经诱发电位和传导速度（ＳＮＡＰ、ＳＮＣＶ）及体感诱发电位（ＳＥＰ）进行分析诊断。１９９７年起，对１１８例臂丛根性损伤加测颈椎旁肌ＥＭＧ、双侧膈肌的ＣＭＡＰ和斜方肌的ＥＭＧ、ＣＭＡＰ进行诊断。结果１９９７年至今，臂丛根性损伤神经电图－肌电图的诊断和术中发现相比，诊断完全符合率为８０％，完全及基本符合率为９５．４％，比１９９７年前分别提高１４．１％和１０．３％。结论臂丛神经根性损伤加测椎旁肌ＥＭＧ、膈神经、副神经肌电可提高臂丛根性损伤尤其是Ｃ５节后损伤的肌电诊断正确率。     

Neuropathy in type 1 diabetic renal transplanted patients

This study was undertaken to study the changes in neuropathy in type 1 diabetic patients with end-stage renal disease (ESRD) after renal transplantation. From April 2007 to June 2010, 30 renal transplanted patients with type 1 diabetes mellitus (RT) and 30 type 1 diabetic patients with ESRD were enrolled in this study. Electroneurodiagnostic tests of peroneal, sural, ulnar, and median nerves were performed. Nerve conduction velocity (NCV), compound motor action potentials (CMAPs), and sensory nerve action potentials (SNAPs) were analyzed at 6, 12, and 18 months after renal transplantation. The NCV improved in the RT group in 18 months of the follow-up period (P <0.01 versus baseline). This parameter worsened significantly in the control group throughout the study period (P = 0.03), but in the cross-sectional analysis between the groups, we could not find any remarkable differences (P = 0.07). Both SNAP and CMAP amplitudes improved in the RT (SNAP Sural = 0.04, SNAP Median = 0.01 and CAMP Peroneal = 0.03, CAMP Ulnar = 0.02) but worsened in the control group (SNAP Sural < 0.001, SAP Median < 0.01 and CAMP Peroneal < 0.01, CAMP Ulnar < 0.01). Comparison of both groups did not show any significant statistical changes. Electroneurodiagnostic values improved after renal transplantation in type 1 diabetic patients with ESRD, but cross-sectional analysis did not reveal statistically significant differences between the studied groups.     

Electrophysiological aspects of nervous conduction in uremia

Some neurophysiological techniques have been employed in clinical nephrology to record abnormalities of nervous conduction in central and peripheral pathways. The electrical monitoring on the peripheral and central nervous systems has allowed the detection of uremic neural injury, the diagnosis of specific electrophysiological abnormalities, the evaluation of various treatments employed and the identification of those abnormalities that uremia can induce. A group of 156 subjects subdivided into four groups were examined: 100 healthy subjects (64 M, 36 F); 56 patients (21 glomerulonephritis, 14 pyelonephritis, 5 nephrolithiasis, 5 polycystic kidney, 4 nephroangiosclerosis, 7 undetermined) with chronic renal failure treated with a conventional low nitrogen diet (CLND, 0.6 g/kg b.w./d. of proteins), 8 of whom passed from CLND to a very low nitrogen diet supplemented with alpha-keto-analogues; a group of 22 of these 56 underwent a regular dialysis treatment for 12 to 15 hours/weekly for 40.5 +/- 10.2 months. Three patients of the CLND group and 13 patients underwent renal transplantation after a variable period of RDT. In the uremic patients we found different populations of motor unit potentials; a decreased MNCV was found in 35% of the CLND patients, RDT patients had slowed MNCV in 42%. The SNCV was compromised more frequently than the MNCV. An increased duration of evoked potentials was sometimes observed in CLND and RDT patients inducing us to consider this a hallmark of uremic syndrome. The alpha-keto-analogues and HD/HP treated patients showed an improvement in several features.(ABSTRACT TRUNCATED AT 250 WORDS)