Nerve conduction models in myelinated and unmyelinated nerves based on three-dimensional electrostatic interaction

Until now, nerve conduction has been described on the basis of equivalent circuit model and cable theory, both of which supposed closed electric circuits spreading inside and outside the axoplasm. With these conventional models, we can simulate the propagating pattern of action potential along the axonal membrane based on Ohm＇s law and Kirchhoff＇s law. However, we could not fully explain the different conductive patterns in unmyelinated and myelinated nerves with these theories. Also, whether we can really suppose closed electrical circuits in the actual site of the nerves or not has not been fully discussed yet. In this report, a recently introduced new theoretical model of nerve conduction based on electrostatic molecular interactions within the axoplasm will be reviewed. With this new approach, we can explain the different conductive patterns in unmyelinated and myelinated nerves. This new mathematical conductive model based on electrostatic compressional wave in the intracellular fluid may also be able to explain the signal integration in the neuronal cell body and the back-propagation mechanism from the axons to the dendrites. With this new mathematical nerve conduction model based on electrostatic molecular interactions within the intracellular fluid, we may be able to achieve an integrated explanation for the physiological phenomena taking place in the nervous system.

Abnormality of peripheral nerve conduction velocity associated with illness course, symptoms and fasting blood glucose in patients with type 2 diabetes mellitus

BACKGROUND: It has shown that abnormality of peripheral nerve conduction velocity during onset of diabetes mellitus is not related to age and sex, but to symptoms, illness course and level of fasting blood glucose. OBJECTIVE: To measure correlation of abnormality of peripheral nerve conduction velocity with various illness courses, symptoms and levels of fasting blood glucose of patients with type 2 diabetes mellitus. DESIGN: Case analysis. SETTING: Department of Neurology, Central People's Hospital of Huizhou. PARTICIPANTS: A total of 128 patients who were diagnosed as type 2 diabetes mellitus were selected from Central People's Hospital of Huizhou from September 2001 to October 2005. There were 75 males and 53 females aged 32-83 years and the illness course ranged from 1 month to 20 years. METHODS: All 128 patients with type 2 diabetes mellitus received neuro-electrophysiological study and their clinical data were retrospectively analyzed to measure peripheral nerve conduction velocity and fasting blood glucose so as to investigate the correlation of peripheral nerve conduction velocity with clinical symptoms, illness course and levels of fasting blood glucose. MAIN OUTCOME MEASURES: Correlation of peripheral nerve conduction velocity with clinical symptoms, illness course and levels of fasting blood glucose. RESULTS: All 128 patients with type 2 diabetes mellitus were involved in the final analysis. ① Among 128 patients, 114 patients had abnormality of peripheral nerve conduction velocity; 110 patients had clinical symptoms, including 102 patients having abnormality of peripheral nerve conduction velocity; 18 patients did not have clinical symptoms, including 12 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=8.275, P =0.04). ② Among 128 patients, illness course of 75 patients was equal to or less than 5 years, including 27 patients having abnormality of peripheral nerve conduction velocity; illness course of 53 patients was more than 5 years, including 35 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=11.469, P =0.003). ③ Among 128 patients, levels of fasting blood glucose of 75 patients was equal to or lower than 11 mmol/L, including 41 patients having abnormality of peripheral nerve conduction velocity; levels of fasting blood glucose of 53 patients was higher than 11 mmol/L, including 38 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (χ 2=4.023, P =0.134). CONCLUSION: ① Abnormality of peripheral nerve conduction velocity of patients with type 2 diabetes mellitus is related to illness courses and clinical symptoms. The longer the illness course is, the severer the abnormality of peripheral nerve conduction velocity is. Abnormality of peripheral nerve conduction velocity always occurs on patients who have clinical symptoms. ② Abnormality of peripheral nerve conduction velocity is not related to levels of fasting blood glucose.

Effects of pestle needle on nerve conduction velocity and inflammatory injury in patients with diabetic peripheral neuropathy

Background:Diabetic peripheral neuropathy(DPN)is one of the most common complications of diabetes mellitus.Impaired neurological function is one of the main characteristics of DPN and is strongly associated with the inflammatory response.Our previous studies have confirmed that pestle needle can improve the nerve function of patients with DPN.But the mechanism of pestle needle treatment of DPN is still unclear.Methods:A total of 70 DPN patients who met the inclusion criteria were randomly divided into two groups.Control group(CG)(n=35)received DPN conventional treatment and the pestle needle group(PNG)(n=35)received pestle needle therapy at Zhiyang(DU09)eight array,Mingmen(DU04)eight array and Heche Road(from Mingmen(DU04)to Changqiang(DU01)),Zusanli(ST36),Sanyinjiao(SP06),Taixi(KI03)and Yongquan(KI01).Patients in the PNG group were required to take this treatment for 4 weeks,5 times a week.Examination indexes were collected before and after treatment,respectively.Nerve function was examined using the Toronto clinical scoring system and nerve conduction velocity detection.Serum inflammatory factors were measured by enzyme linked immunosorbent assay.Results:The Toronto clinical scoring system was significantly reduced in the PNG compared with the CG after treatment.The sensory nerve conduction velocity and motor nerve conduction velocity of the right peroneal and median nerves were significantly faster in the PNG than those in the CG(P<0.05).After treatment,serum interleukin-1 beta,interleukin-6 and tumor necrosis factor-alpha levels decreased in both groups,and the improvement of PNG was better than CG(P<0.05).Conclusion:The pestle needle can significantly improve the symptoms and nerve conduction velocity of DPN,and its mechanism may be related to the reduction of inflammatory factors.

Exploring the Potential of a Questionnaire in Predicting Results of Nerve Conduction Studies in Patients with Suspected Carpal Tunnel Syndrome: Exploring a Clinician and Patient Complete Version

This evaluation of the Carpal Tunnel Questionnaire (CTQ) was designed to establish the validity and flexibility of its potential use both within a primary and secondary care setting. The questionnaire was originally designed to predict the positive and negative outcome of Nerve Conduction Studies (NCS) in those patients with suspected Carpal Tunnel Syndrome (CTS). Prior to being seen by the hand specialist patients who had been referred with suspected CTS where asked to complete the CTQ. These questionnaires were coded and filed by the clinic nurse. The hand specialist then completed the questionnaire with the patient preceding NCS. Questionnaires were scored subsequent to the appointment. Results for the hand specialist completed questionnaire showed an 80% specificity and 92% sensitivity regarding the ability of the CTQ to predict a positive NCS using a pre-determine cut-off score. The patient completed questionnaire showed a 70.67% specificity and 72% sensitivity. Using receiver operating characteristics a threshold score could be determined to achieve 100% sensitivity/specificity for both questionnaires. This questionnaire provides a useful addition in the assessment of patients with suspected carpal tunnel syndrome and could be used in a range of clinical settings although the scoring cut-off may need to be adapted depending on whether the questionnaire was completed by the clinician or patient. Using the questionnaire in a clinical setting would reduce the requirement for NCS by 60%, this would offer significant time and cost savings.

Motor versus Sensory Nerve Conduction Monitoring of Median Nerve during Carpal Tunnel Surgery

Background/Aim: Carpal tunnel syndrome (CTS) is one of the most common compressive, canalicular neuropathies of the upper extremities, causing hand pain and impaired function. This clinical study was designed to compare the intraoperative median nerve distal motor latency (DML) versus the distal sensory latency (DSL) and sensory nerve conduction velocity (SNCV) during surgical treatment of CTS. Patients and Methods: A total number of 36 wrists in 30 patients with CTS diagnosed by preoperative median MNCS who underwent surgical intervention for median nerve release. Intraoperative measurements of motor distal latency (DML) and proximal latency, amplitude, and conduction velocity and distal sensory latency (DSL), amplitude, and conduction velocity of both the median and ulnar nerves before and after division of the flexor retinaculum (FR). Results: A significant decrease of the intraoperative median nerve distal motor latency (DML) after release (8.89 ± 0.93) in comparison with the preoperative median nerve DML (6.24 ± 1.06) with (p < 0.001*). But intraoperative distal sensory latency (DSL) and sensory nerve conduction velocity (SNCVM) show non-significant decrease (p = 0.161). Conclusion: Intraoperative monitoring of median nerve show rapidly improve Intraoperative motor nerve conduction than the sensory nerve conduction after release the FR during carpal tunnel surgery.

Effects of Head-down Tilt on Nerve Conduction in Rhesus Monkeys

Background： Few studies have focused on peripheral nerve conduction during exposure to microgravity. The -6° head-down tilt （HDT） comprises an experimental model used to simulate the space flight environment. This study investigated nerve conduction characteristics of rhesus monkeys before and alter prolonged exposure to H DT. Methods： Six rhesus monkeys （3-4 years old） were tilted backward 6° from the horizontal. Nerve conduction studies （NCSs） were performed on the median, ulnar, tibial, and fibular motor nerves. Analysis of variance with a randomized block design was conducted to compare the differences in the NCS belbre and 7, 2 l, and 42 days alter the 6° HDT. Results： The proximal amplitude of the CMAP of the median nerve was significantly decreased at 21 and 42 days of HDT compared with the amplitude before HDT （4.38 ± 2.83 vs. 8.40 ±2.66 mV, F = 4.85, P = 0.013 and 3.30± 2.70 vs. 8.40± 2.66 mV, F = 5.93, P = 0.004, respectively）. The distal amplitude of the CMAP of the median nerve was significantly decreased at 7, 21, and 42 days of HDT compared with the amplitude before HDT （7.28 ± 1.27 vs. 10.25 ± 3.40 mV, F= 4.03, P = 0.039; 5.05 ± 2.01 vs. 10.25 ± 3.40 mV, F = 6.25, P = 0.04; and 3.95 ± 2.79 vs. 10.25 ± 3.40 mV, F = 7.35, F=- 0.01; respectively）. The proximal amplitude of the CMAP of the tibial nerve was significantly decreased at 42 days of HDT compared with the amplitude betbre HDT （6.14± 1.94 vs. 11.87± 3.19 mV, F = 5.02, P = 0.039）. Conclusions： This study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity.

Preliminary Study on the Lesion Location and Prognosis of Cubital Tunnel Syndrome by Motor Nerve Conduction Studies

Background：To study lesions＇ location and prognosis of cubital tunnel syndrome （CubTS） by routine motor nerve conduction studies （MNCSs） and short-segment nerve conduction studies （SSNCSs,inching test）.Methods：Thirty healthy subjects were included and 60 ulnar nerves were studied by inching studies for normal values.Sixty-six patients who diagnosed CubTS clinically were performed bilaterally by routine MNCSs and SSNCSs.Follow-up for 1-year,the information of brief complaints,clinical symptoms,and physical examination were collected.Results：Sixty-six patients were included,88 of nerves was abnormal by MNCS,while 105 was abnormal by the inching studies.Medial epicondyle to 2 cm above medial epicondyle is the most common segment to be detected abnormally （59.09％）,P ＜ 0.01.Twenty-two patients were followed-up,17 patients＇ symptoms were improved.Most of the patients were treated with drugs and modification of bad habits.Conclusions：（1） SSNCSs can detect lesions of compressive neuropathy in CubTS more precisely than the routine motor conduction studies.（2） SSNCSs can diagnose CubTS more sensitively than routine motor conduction studies.（3） In this study,we found that medial epicondyle to 2 cm above the medial epicondyle is the most vulnerable place that the ulnar nerve compressed.（4） The patients had a better prognosis who were abnormal in motor nerve conduction time only,but not amplitude in compressed lesions than those who were abnormal both in velocity and amplitude.Our study suggests that SSNCSs is a practical method in detecting ulnar nerve compressed neuropathy,and sensitive in diagnosing CubTS.The compound muscle action potentials by SSNCSs may predict prognosis of CubTS.

Nerve conduction studies in patients with dermatomyositis or polymyositis

Background Involvement of peripheral nerves in dermatomyositis （DM） and polymyositis （PM） is less well known. In the present study we retrospectively analyzed the clinical and electrophysiological records of hospital inpatients with a diagnosis of DM or PM to investigate the association of DM/PM and peripheral neuropathy. Methods The data of inpatients diagnosed with DM or PM were collected in Peking Union Medical College Hospital, and 186 patients （118 patients with DM and 68 with PM） were retrospectively analyzed. Nerve conduction studies （NCSs） of the median nerve, ulnar nerve, posterior tibial nerve, and common peroneal nerve were examined simultaneously. Results There were 71 （38.2%） patients with abnormal NCS findings, 37 （19.9%） with pure motor involvement （decreased compound muscle action potential, CMAP）, and 34 （18.3%） with peripheral neuropathy. Of the 34 peripheral neuropathy patients, 14 （7.5%） had polyneuropathy, 1 （0.5%） had multiple mononeuropathy, 16 （8.6%） had carpal tunnel syndrome （CTS）, 1 （0.5%） had trigeminal sensory neuropathy, 1 （0.5%） had ulnar sensory neuropathy, and 1 （0.5%） had brachial plexus involvement. The prevalence of malignant disease （3/34, 8.8%）, other connective tissue diseases （CTDs） （7/34, 20.6%） and diabetes （6/34, 17.6%） was significantly greater in DM/PM patients with peripheral neuropathy （X2=15.855, P=0.000） compared with DM/PM patients without involvement of peripheral nerves （5/115, 4.3% and 7/115, 6.1%, respectively）. Conclusions Peripheral neuropathy in DM/PM often suggests a complication with cancer, other CTDs, diabetes or CTS. From a practical point of view, NCS for DM/PM may help find the underlying disorders.

Effect of Elbow Position on Short-segment Nerve Conduction Study in Cubital Tunnel Syndrome

Background： The appropriate elbow position of short-segment nerve conduction study （SSNCS） to diagnose cubital tunnel syndrome （CubTS） is still controversial. The goal of this study was to determine the effect of different elbow positions at full extension and 70° flexion on SSNCS in CubTS. Methods： In this cross-sectional study, the clinical data of seventy elbows from 59 CubTS patients between September, 2011 and December, 2014 in the Peking University First Hospital were included as CubTS group. Moreover, thirty healthy volunteers were included as the healthy group. SSNCS were conducted in all subjects at elbow fhll extension and 70° elbow flexion. Paired nonparametric test, bivariate correlation, Bland-Altman, and Chi-squared test analysis were used to compare the effectiveness of elbow full extension and 70° flexion elbow positions on SSNCS in CubTS patients. Results： Data of upper limit was calculated from healthy group, and abnormal latency was judged accordingly. CubTS group＇s latency and compound muscle action potential （CMAP） of each segment at 70° elbow flexion by SSNCS was compared with lull extension position, no statistically significant difference were found （all P 〉 0.05）. Latency and CMAP of each segment at elbow full extension and 70° flexion were correlated （all P 〈 0 elbow （P - 0.43）, and the latency （P = 0.15） and the CMAP （P = 01）, except the latency of segment of 4 cm to 6 cm above 0.06） of segment of 2 cm to 4 cm below elbow. Bivariate correlation and Bland-Altman analysis proved the correlation between elbow full extension and 70° flexion. Especially in segments across the elbow （2 cm above the elbow and 2 cm below it）, latency at elbow full extension and 70° flexion were strong direct associated（r=0.83, P〈0.01;r=0.55, P〈0.01）,andsodidtheCMAP（r 0.49, P〈0.01;r=0.72, P〈0.01）.Therewasno statistically significant difference in abnormality of each segment at full extension as measured by SSNCS compared with that at 70° flexion （P 〉 0.05, respectively）. Conclusions： There was no statistically significant difference in the diagnosis of CubTS with the elbow at full extension compared with that at 70° flexion during SSNCS. We suggest that elbow positon at full extension can also be used during SSNCS.

BLOW－UP AND DIE－OUT OF SOLUTIONS OF NONLINEAR PSEUDO-HYPERBOLIC EQUATIONS OF GENERALIZED NERVE CONDUCTION TYPE

This paper considers the initial boundary value problems with three types of the boundary conditions for nonlinear pseudo-hyperbolic equations of generalized nerve conduction type, using foe eigenfunction method, the conditions for which the solutions blow-up and die-out in the finile time are got.

Promising application of a new ulnar nerve compound muscle action potential measurement montage in amyotrophic lateral sclerosis:a prospective cross-sectional study

Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist.This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential.In this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital.The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage.In the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings.In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral sclerosis.In addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores.These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position,and that this method is more suitable for monitoring disease progression than the traditional montage.This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.

Improvement in acupoint selection for acupuncture of nerves surrounding the injury site: electro-acupuncture with Governor vessel with local meridian acupoints

Peripheral nerve injury not only affects the site of the injury, but can also induce neuronal apop- tosis at the spinal cord. However, many acupuncture clinicians still focus only on the injury site, selecting acupoints entirely along the injured nerve trunk and neglecting other regions; this may delay onset of treatment efficacy and rehabilitation. Therefore, in the present study, we compared the clinical efficacy of acupuncture at Governor vessel and local meridian acupoints combined （GV/LM group） with acupuncture at local meridian acupoints alone （LM group） in the treatment of patients with peripheral nerve injury. In the GV/LM group （n = 15）, in addition to meridian acupoints at the injury site, the following acupoints on the Governor vessel were stimulated： Baihui （GV20）, Fengfu （GV16）, Dazhui （GV14）, and Shenzhu （GV12）, selected to treat nerve injury of the upper limb, and Jizhong （GV6）, Mingmen （GV4）, Yaoyangguan （GV3）, and Yaoshu （GV2） to treat nerve injury of the lower limb. In the LM group （n = 15）, only me- ridian acupoints along the injured nerve were selected. Both groups had electroacupuncture treatment for 30 minutes, once a day, 5 times per week, for 6 weeks. Two cases dropped out of the LM group. A good or excellent clinical response was obtained in 80% of the patients in the GV/ LM group and 38.5% of the LM group. In a second study, an additional 20 patients underwent acupuncture with the same prescription as the GV/LM group. Electomyographic nerve conduc- tion tests were performed before and after acupuncture to explore the mechanism of action of the treatment. An effective response was observed in 80.0% of the patients, with greater motor nerve conduction velocity and amplitude after treatment, indicating that electroacupuncture on specific Governor vessel acupoints promotes functional motor nerve repair after peripheral nerve injury. In addition, electromyography was performed before, during and after electroacu- puncture in one patient with radial nerve injury. After a single session, the patient＇s motor nerve conduction velocity increased by 23.2%, indicating that electroacupuncture at Governor vessel acupoints has an immediate therapeutic effect on peripheral nerve injury. Our results indicate that Governor vessel and local meridian acupoints used simultaneously promote functional repair after peripheral nerve injury. The mechanism of action may arise from an improvement of the local microenvironment in injured nervous tissue, as well as immediate effects of Governor vessel and local meridian acupoint stimulation to ensure the continuity between the peripheral and central nervous systems.

Efficacy and safety of nerve growth factor for the treatment of neurological diseases:a meta-analysis of 64 randomized controlled trials involving 6,297 patients

OBJECTIVE： China is the only country where nerve growth factor is approved for large-scale use as a clinical medicine. More than 10 years ago, in 2003, nerve growth factor injection was listed as a national drug. The goal of this article is to evaluate comprehensively the efficacy and safety of nerve growth factor for the treatment of neurological diseases. DATA RETRIEVAL： A computer-based retrieval was performed from six databases, including the Cochrane Library, PubMed, EMBASE, Sino Med, CNKI, and the VIP database, searching from the clinical establishment of nerve growth factor for treatment until December 31, 2013. The key words for the searches were ＂nerve growth factor, randomized controlled trials＂ in Chinese and in English. DATA SELECTION： Inclusion criteria： any study published in English or Chinese referring to randomized controlled trials of nerve growth factor; patients with neurological diseases such as peripheral nerve injury, central nerve injury, cranial neuropathy, and nervous system infections; patients older than 7 years; similar research methods and outcomes assessing symptoms; and measurement of nerve conduction velocities. The meta-analysis was conducted using Review Manager 5.2.3 software. MAIN OUTCOME MEASURES： The total effective rate, the incidence of adverse effects, and the nerve conduction velocity were recorded for each study. RESULTS： Sixty-four studies involving 6,297 patients with neurological diseases were included. The total effective rate in the group treated with nerve growth factor was significantly higher than that in the control group （P 〈 0.0001, RR： 1.35, 95%CI： 1.30-1.40）. The average nerve conduction velocity in the nerve growth factor group was significantly higher than that in the control group （P 〈 0.00001, MD. 4.59 m/s, 95%CI： 4.12-5.06）. The incidence of pain or sclero- ma at the injection site in the nerve growth factor group was also higher than that in the control group （P 〈 0.00001, RR： 6.30, 95%CI： 3.53-11.27）, but such adverse effects were mild. CONCLUSION： Nerve growth factor can significantly improve nerve function in patients with nervous system disease and is safe and effective.

Saikosaponin a increases interleukin-10 expression and inhibits scar formation after sciatic nerve injury

Nerve scarring after peripheral nerve injury can severely hamper nerve regeneration and functional recovery.Further,the anti-inflammatory cytokine,interleukin-10,can inhibit nerve scar formation.Saikosaponin a（SSa） is a monomer molecule extracted from the Chinese medicine,Bupleurum.SSa can exert anti-inflammatory effects in spinal cord injury and traumatic brain injury.However,it has not been shown whether SSa can play a role in peripheral nerve injury.In this study,rats were randomly assigned to three groups.In the sham group,the left sciatic nerve was directly sutured after exposure.In the sciatic nerve injury（SNI） ＋ SSa and SNI groups,the left sciatic nerve was sutured and continuously injected daily with SSa（10 mg/kg） or an equivalent volume of saline for 7 days.Enzyme linked immunosorbent assay results demonstrated that at 7 days after injury,interleukin-10 level was considerably higher in the SNI ＋ SSa group than in the SNI group.Masson staining and western blot assay demonstrated that at 8 weeks after injury,type I and III collagen content was lower and nerve scar formation was visibly less in the SNI ＋ SSa group compared with the SNI group.Simultaneously,sciatic functional index and nerve conduction velocity were improved in the SNI ＋ SSa group compared with the SNI group.These results confirm that SSa can increase the expression of the anti-inflammatory factor,interleukin-10,and reduce nerve scar formation to promote functional recovery of injured sciatic nerve.

Nerve root magnetic stimulation improves locomotor function following spinal cord injury with electrophysiological improvements and cortical synaptic reconstruction

Following a spinal cord injury,there are usually a number of neural pathways that remain intact in the spinal cord.These residual nerve fibers are important,as they could be used to reconstruct the neural circuits that enable motor function.Our group previously designed a novel magnetic stimulation protocol,targeting the motor cortex and the spinal nerve roots,that led to significant improvements in locomotor function in patients with a chronic incomplete spinal cord injury.Here,we investigated how nerve root magnetic stimulation contributes to improved locomotor function using a rat model of spinal cord injury.Rats underwent surgery to clamp the spinal cord at T10;three days later,the rats were treated with repetitive magnetic stimulation(5 Hz,25 pulses/train,20 pulse trains)targeting the nerve roots at the L5-L6 vertebrae.The treatment was repeated five times a week over a period of three weeks.We found that the nerve root magnetic stimulation improved the locomotor function and enhanced nerve conduction in the injured spinal cord.In addition,the nerve root magnetic stimulation promoted the recovery of synaptic ultrastructure in the sensorimotor cortex.Overall,the results suggest that nerve root magnetic stimulation may be an effective,noninvasive method for mobilizing the residual spinal cord pathways to promote the recovery of locomotor function.

A novel chronic nerve compression model in the rat

Current animal models of chronic peripheral nerve compression are mainly silicone tube models. However, the cross section of the rat sciatic nerve is not a perfect circle, and there are differences in the diameter of the sciatic nerve due to individual differences. The use of a silicone tube with a uniform internal diameter may not provide a reliable and consistent model. We have established a chronic sciatic nerve compression model that can induce demyelination of the sciatic nerve and lead to atrophy of skeletal muscle. In 3-week-old pups and adult rats, the sciatic nerve of the right hind limb was exposed, and a piece of surgical latex glove was gently placed under the nerve. N-butyl-cyanoacrylate was then placed over the nerve, and after it had set, another piece of glove latex was placed on top of the target area and allowed to adhere to the first piece to form a sandwich-like complex. Thus, a chronic sciatic nerve compression model was produced. Control pups with latex or N-butyl-cyanoacrylate were also prepared. Functional changes to nerves were assessed using the hot plate test and electromyography. Immunofluorescence and electron microscopy analyses of the nerves were performed to quantify the degree of neuropathological change. Masson staining was conducted to assess the degree of fibrosis in the gastrocnemius and intrinsic paw muscles. The pup group rats subjected to nerve compression displayed thermal hypoesthesia and a gradual decrease in nerve conduction velocity at 2 weeks after surgery. Neuropathological studies demonstrated that the model caused nerve demyelination and axonal irregularities and triggered collagen deposition in the epineurium and perineurium of the affected nerve at 8 weeks after surgery. The degree of fibrosis in the gastrocnemius and intrinsic paw muscles was significantly increased at 20 weeks after surgery. In conclusion, our novel model can reproduce the functional and histological changes of chronic nerve compression injury that occurs in humans and it will be a useful new tool for investigating the mechanisms underlying chronic nerve compression.

Boric acid reduces axonal and myelin damage in experimental sciatic nerve injury

The aim of this study was to investigate the effects of boric acid in experimental acute sciatic nerve injury. Twenty-eight adult male rats were randomly divided into four equal groups （n = 7）： control （C）, boric acid （BA）, sciatic nerve injury （I） , and sciatic nerve injury ＋ boric acid treatment （BAI）. Sciatic nerve injury was generated using a Yasargil aneurysm clip in the groups I and BAI. Boric acid was given four times at 100 mg/kg to rats in the groups BA and BAI after injury （by gavage at 0, 24, 48 and 72 hours） but no injury was made in the group BA. In vivo electrophysiological tests were performed at the end of the day 4 and sciatic nerve tissue samples were taken for histopathological examination. The amplitude of compound action potential, the nerve conduction velocity and the number of axons were significantly lower and the myelin structure was found to be broken in group I compared with those in groups C and BA. However, the amplitude of the compound action potential, the nerve conduction velocity and the number of axons were significantly greater in group BAI than in group I. Moreover, myelin injury was significantly milder and the intensity of nuclear factor kappa B immunostaining was significantly weaker in group BAI than in group I. The results of this study show that administration of boric acid at 100 mg/kg after sciatic nerve injury in rats markedly reduces myelin and axonal injury and improves the electrophysiological function of injured sciatic nerve possibly through alleviating oxidative stress reactions.

Propofol's effect on the sciatic nerve Harmful or protective?

Propofol can inhibit the inflammatory response and reduce the secretion and harmful effects of as-trocyte-derived proinflammatory cytokines. In this study, after propofol was injected into the injured sciatic nerve of mice, nuclear factor kappa B expression in the L 4-6 segments of the spinal cord in the injured side was reduced, apoptosis was decreased, nerve myelin defects were al eviated, and the nerve conduction block was lessened. The experimental findings indicate that propofol inhibits the inflammatory and immune responses, decreases the expression of nuclear factor kappa B, and reduces apoptosis. These effects of propofol promote regeneration fol owing sciatic nerve injury.

Pulsed electrical stimulation protects neurons in the dorsal root and anterior horn of the spinal cord after peripheral nerve injury

Most studies on peripheral nerve injury have focused on repair at the site of injury, but very few have examined the effects of repair strategies on the more proximal neuronal cell bodies. In this study, an approximately 10-mm-long nerve segment from the ischial tuberosity in the rat was transected and its proximal and distal ends were inverted and sutured. The spinal cord was subjected to pulsed electrical stimulation at T10 and L3, at a current of 6.5 m A and a stimulation frequency of 15 Hz, 15 minutes per session, twice a day for 56 days. After pulsed electrical stimulation, the number of neurons in the dorsal root ganglion and anterior horn was increased in rats with sciatic nerve injury. The number of myelinated nerve fibers was increased in the sciatic nerve. The ultrastructure of neurons in the dorsal root ganglion and spinal cord was noticeably improved. Conduction velocity of the sciatic nerve was also increased. These results show that pulsed electrical stimulation protects sensory neurons in the dorsal root ganglia as well as motor neurons in the anterior horn of the spinal cord after peripheral nerve injury, and that it promotes the regeneration of peripheral nerve fibers.

Anterior subcutaneous transposition of the ulnar nerve improves neurological function in patients with cubital tunnel syndrome

Although several surgical procedures exist for treating cubital tunnel syndrome, the best surgical option remains controversial. To evaluate the efficacy of anterior subcutaneous transposition of the ulnar nerve in patients with moderate to severe cubital tunnel syndrome and to analyze prognostic factors, we retrospectively reviewed 62 patients（65 elbows） diagnosed with cubital tunnel syndrome who underwent anterior subcutaneous transposition. Preoperatively, the initial severity of the disease was evaluated using the Mc Gowan scale as modified by Goldberg： 18 patients（28%） had grade IIA neuropathy, 20（31%） had grade IIB, and 27（42%） had grade III. Postoperatively, according to the Wilson ＆ Krout criteria, treatment outcomes were excellent in 38 patients（58%）, good in 16（25%）, fair in 7（11%）, and poor in 4（6%）, with an excellent and good rate of 83%. A negative correlation was found between the preoperative Mc Gowan grade and the postoperative Wilson ＆ Krout score. The patients having fair and poor treatment outcomes had more advanced age, lower nerve conduction velocity, and lower action potential amplitude compared with those having excellent and good treatment outcomes. These results suggest that anterior subcutaneous transposition of the ulnar nerve is effective and safe for the treatment of moderate to severe cubital tunnel syndrome, and initial severity, advancing age, and electrophysiological parameters can affect treatment outcome.