scholarly journals Biological laterality and peripheral nerve DTI metrics

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260256
Author(s):  
Scott A. Holmes ◽  
Steven J. Staffa ◽  
Anastasia Karapanagou ◽  
Natalia Lopez ◽  
Victoria Karian ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Fiber ◽  
Magnetization Transfer ◽  
Mean Diffusivity ◽  
Estimating Equation ◽  
Nerve Fibers ◽  
Equation Modeling ◽  
Main Effect ◽  
Fibular Nerve

Background and purpose Clinical comparisons do not usually take laterality into account and thus may report erroneous or misleading data. The concept of laterality, well evaluated in brain and motor systems, may also apply at the level of peripheral nerves. Therefore, we sought to evaluate the extent to which we could observe an effect of laterality in MRI-collected white matter indices of the sciatic nerve and its two branches (tibial and fibular). Materials and methods We enrolled 17 healthy persons and performed peripheral nerve diffusion weighted imaging (DWI) and magnetization transfer imaging (MTI) of the sciatic, tibial and fibular nerve. Participants were scanned bilaterally, and findings were divided into ipsilateral and contralateral nerve fibers relative to self-reporting of hand dominance. Generalized estimating equation modeling was used to evaluate nerve fiber differences between ipsilateral and contralateral legs while controlling for confounding variables. All findings controlled for age, sex and number of scans performed. Results A main effect of laterality was found in radial, axial, and mean diffusivity for the tibial nerve. Axial diffusivity was found to be lateralized in the sciatic nerve. When evaluating mean MTR, a main effect of laterality was found for each nerve division. A main effect of sex was found in the tibial and fibular nerve fiber bundles. Conclusion For the evaluation of nerve measures using DWI and MTI, in either healthy or disease states, consideration of underlying biological metrics of laterality in peripheral nerve fiber characteristics need to considered for data analysis. Integrating knowledge regarding biological laterality of peripheral nerve microstructure may be applied to improve how we diagnosis pain disorders, how we track patients’ recovery and how we forecast pain chronification.

scholarly journals DTI and MTR Measures of Nerve Fiber Integrity in Pediatric Patients With Ankle Injury

2021 ◽  
Vol 9 ◽  
Author(s):  
Scott A. Holmes ◽  
Anastasia Karapanagou ◽  
Steven J. Staffa ◽  
David Zurakowski ◽  
Ronald Borra ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Peripheral Nerve ◽  
Nerve Fiber ◽  
Nerve Injury ◽  
Diffusion Tensor ◽  
Nerve Fibers ◽  
Ankle Injury ◽  
Future Research ◽  
Post Injury ◽  
Fibular Nerve

Acute peripheral nerve injury can lead to chronic neuropathic pain. Having a standardized, non-invasive method to evaluate pathological changes in a nerve following nerve injury would help with diagnostic and therapeutic assessments or interventions. The accurate evaluation of nerve fiber integrity after injury may provide insight into the extent of pathology and a patient's level of self-reported pain. The aim of this investigation was to evaluate the extent to which peripheral nerve integrity could be evaluated in an acute ankle injury cohort and how markers of nerve fiber integrity correlate with self-reported pain levels in afferent nerves. We recruited 39 pediatric participants with clinically defined neuropathic pain within 3 months of an ankle injury and 16 healthy controls. Participants underwent peripheral nerve MRI using diffusion tensor (DTI) and magnetization transfer imaging (MTI) of their injured and non-injured ankles. The imaging window was focused on the branching point of the sciatic nerve into the tibial and fibular division. Each participant completed the Pain Detection Questionnaire (PDQ). Findings demonstrated group differences in DTI and MTI in the sciatic, tibial and fibular nerve in the injured ankle relative to healthy control and contralateral non-injured nerve fibers. Only AD and RD from the injured fibular nerve correlated with PDQ scores which coincides with the inversion-dominant nature of this particular ankle injuruy cohort. Exploratory analyses highlight the potential remodeling stages of nerve injury from neuropathic pain. Future research should emphasize sub-acute time frames of injury to capture post-injury inflammation and nerve fiber recovery.

scholarly journals Magnetization Transfer Ratio of Peripheral Nerve and Skeletal Muscle

2021 ◽  
Author(s):  
Olivia Fösleitner ◽  
Véronique Schwehr ◽  
Tim Godel ◽  
Fabian Preisner ◽  
Philipp Bäumer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Weight ◽  
Sciatic Nerve ◽  
Linear Regression ◽  
Peripheral Nerve ◽  
Regression Model ◽  
Multiple Linear Regression ◽  
Linear Regression Model ◽  
Magnetization Transfer ◽  
Multiple Linear Regression Model

Abstract Purpose To assess the correlation of peripheral nerve and skeletal muscle magnetization transfer ratio (MTR) with demographic variables. Methods In this study 59 healthy adults evenly distributed across 6 decades (mean age 50.5 years ±17.1, 29 women) underwent magnetization transfer imaging and high-resolution T2-weighted imaging of the sciatic nerve at 3 T. Mean sciatic nerve MTR as well as MTR of biceps femoris and vastus lateralis muscles were calculated based on manual segmentation on six representative slices. Correlations of MTR with age, body height, body weight, and body mass index (BMI) were expressed by Pearson coefficients. Best predictors for nerve and muscle MTR were determined using a multiple linear regression model with forward variable selection and fivefold cross-validation. Results Sciatic nerve MTR showed significant negative correlations with age (r = −0.47, p < 0.001), BMI (r = −0.44, p < 0.001), and body weight (r = −0.36, p = 0.006) but not with body height (p = 0.55). The multiple linear regression model determined age and BMI as best predictors for nerve MTR (R2 = 0.40). The MTR values were different between nerve and muscle tissue (p < 0.0001), but similar between muscles. Muscle MTR was associated with BMI (r = −0.46, p < 0.001 and r = −0.40, p = 0.002) and body weight (r = −0.36, p = 0.005 and r = −0.28, p = 0.035). The BMI was selected as best predictor for mean muscle MTR in the multiple linear regression model (R2 = 0.26). Conclusion Peripheral nerve MTR decreases with higher age and BMI. Studies that assess peripheral nerve MTR should consider age and BMI effects. Skeletal muscle MTR is primarily associated with BMI but overall less dependent on demographic variables.

scholarly journals LONG-TERM OUTCOMES OF RAT SCIATIC NERVE INJURY AND ITS GRAFTING WITH SILICON WIRES-BASED CONDUIT: DISTAL NERVE STUMP HISTOLOGY AND ELECTROMYOGRAPHY RESULTS

2019 ◽  
Vol 15 (3-4) ◽  
pp. 3-9
Author(s):  
V. Likhodiievskyi ◽  
A. Korsak ◽  
D. Skopets ◽  
S. Olefir ◽  
S. Chukhrai ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Nerve Fiber ◽  
Fiber Diameter ◽  
Negative Impact ◽  
Nerve Fibers ◽  
Nerve Injuries ◽  
Nerve Stump ◽  
Distal Nerve ◽  
G Ratio

Relevance. The investigations on trauma epidemiology have shown that both combat- and noncombat-related extremity injuries are often accompanied by nerve injuries. These injuries disproportionately affect young healthy civilians and military officers and has a devastating impact on a patients’ quality of life. Severe nerve injuries, such as nerve trunk injury in continuity (Sunderland 5), that cannot be treated by neurorraphy without tension, require use of nerve gap bridging strategies with different materials and techniques. Objective. This study was aimed to evaluate any positive or negative impact of implanted silicon wires on the quality of nerve fibers at distal nerve stump. Materials and Methods. An experiment was performed on 40 male Whistar rats 2-4 month that were divided to the next groups: I, (n=10) sham-operated, only surgical access to sciatic nerve was performed. II (n=10) with 10 mm sciatic nerve gap that was bridged with autoneurografting. III (n=10) with 10 mm nerve gap that was bridged with allogenic decell aorta filled with 4% carboxymethylcellulose hydrogel. IV (n=10) with 10 mm nerve gap that was bridged with allogenic decell aorta filled with 4% carboxymethylcellulose hydrogel and aligned p-type silicon microvires. Decellularization of allogenic aortas was performed by freeze-thaw cycles. Silicon whiskers were fabricated by Vapor-Liquid-Solid (VLS) method in a cold wall Catalytic Chemical Vapor Deposition (Cat-CVD) chamber, pre-cleaned with hydrofluoric acid and sterilized via 180*C dry heat. 12 weeks after surgery under general anesthesia all rats underwent invasive needle electroneurpmyography with proximal nerve stump stimulation and registration from gastrocnemius muscle. Myograms were recorded and compared by the shape of M-reflex and its amplitude. After myography rats were euthanized under thiopentone overdosage and distal stumps of injured sciatic nerves were harvested for light microscopy. Sciatic nerve transverse slices were stained with nitric silver by modified Bielschowsky method Nerve fiber diameter, axon diameter, myelin sheath thickness and axon-to-nerve fiber diameter ratio (g-ratio) were measured. Results. Performed analysis showed that rats from ІІ and IV groups demonstrated the best quality of nerve fibers in distal nerve stump. That was evidenced by bigger nerve fibers diameter in rats from autologous nerve grafting group and aorta with gel and wires grafting group in comparison with aorta with gel grafting group. Rats from IV demonstrated higher voltage and lower latency of M-reflexes during electromyography. Conclusions. It can be concluded about the possible pro-regenerative impact of implanted silicon wires that was evidenced by better nerve fibers quality at distal nerve stump.

scholarly journals Nogo-C Inhibits Peripheral Nerve Regeneration by Regulating Schwann Cell Apoptosis and Dedifferentiation

2021 ◽  
Vol 14 ◽  
Author(s):  
Bo Jia ◽  
Wei Huang ◽  
Yu Wang ◽  
Peng Zhang ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Cell Apoptosis ◽  
Peripheral Nerve Regeneration ◽  
Nerve Fibers ◽  
Cell Dedifferentiation

While Nogo protein demonstrably inhibits nerve regeneration in the central nervous system (CNS), its effect on Schwann cells in peripheral nerve repair and regeneration following sciatic nerve injury remains unknown. In this research, We assessed the post-injury expression of Nogo-C in an experimental mouse model of sciatic nerve-crush injury. Nogo-C knockout (Nogo-C–/–) mouse was generated to observe the effect of Nogo-C on sciatic nerve regeneration, Schwann cell apoptosis, and myelin disintegration after nerve injury, and the effects of Nogo-C on apoptosis and dedifferentiation of Schwann cells were observed in vitro. We found that the expression of Nogo-C protein at the distal end of the injured sciatic nerve increased in wild type (WT) mice. Compared with the injured WT mice, the proportion of neuronal apoptosis was significantly diminished and the myelin clearance rate was significantly elevated in injured Nogo-C–/– mice; the number of nerve fibers regenerated and the degree of myelination were significantly elevated in Nogo-C–/– mice on Day 14 after injury. In addition, the recovery of motor function was significantly accelerated in the injured Nogo-C–/– mice. The overexpression of Nogo-C in primary Schwann cells using adenovirus-mediated gene transfer promoted Schwann cells apoptosis. Nogo-C significantly reduced the ratio of c-Jun/krox-20 expression, indicating its inhibition of Schwann cell dedifferentiation. Above all, we hold the view that the expression of Nogo-C increases following peripheral nerve injury to promote Schwann cell apoptosis and inhibit Schwann cell dedifferentiation, thereby inhibiting peripheral nerve regeneration.

Excitability changes in peripheral nerve fibers after repetitive electrical stimulation

1979 ◽  
Vol 51 (6) ◽  
pp. 824-833 ◽  
Author(s):  
Ronald J. Ignelzi ◽  
Judith K. Nyquist
Keyword(s):  
Electrical Stimulation ◽  
Peripheral Nerve ◽  
Nerve Fiber ◽  
Conduction Velocity ◽  
Afferent Fiber ◽  
Nerve Fibers ◽  
Velocity Change ◽  
Gate Control Theory ◽  
Peripheral Nerve Fiber ◽  
Repetitive Electrical Stimulation

✓ The Melzack-Wall gate control theory has been invoked to explain the peripheral analgesia resulting from repetitive electrical stimulation of peripheral nerve. This model emphasizes presynaptic inhibitory interactions among afferent fiber terminals in the spinal cord. An alternative explanation, that of velocity change in peripheral nerve fiber conduction, has been suggested by compound action potential studies from our laboratory. The present study was designed to extend this work, and to investigate the single fiber changes subsequent to brief (5- to 20-minute) periods of repetitive, high frequency (180 to 200/sec) electrical stimulation through an implantable peripheral nerve cuff device of the type used clinically for pain relief. Most fibers, regardless of their diameter (estimated from conduction velocity), show one or more of the following characteristics: a transient slowing of conduction velocity, an increase in electrical threshold and/or a decrease in response probability following a period of repetitive electrical stimulation. This supports the hypothesis that there are changes in direct peripheral nerve fiber excitability occurring under conditions simulating clinical electroanalgesia.

scholarly journals Polyglycolic Acid Suture in Peripheral Nerve: An Electron Microscopic Study

1975 ◽  
Vol 2 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Alan R. Hudson ◽  
Juan M. Bilbao ◽  
Daniel Hunter
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Microscopic Study ◽  
Suture Material ◽  
Polyglycolic Acid ◽  
Nerve Fibers ◽  
Nerve Tissue ◽  
Absorbable Suture ◽  
Electron Microscopic ◽  
Minimal Scarring

SUMMARY:The aim of this experiment was to investigate the reaction of peripheral nerve tissue to a synthetic absorbable suture material. Polyglycolic acid suture material was placed within the sciatic nerve of rats and the absorption of the material was investigated by means of electron photomicrographs. It was concluded that placement of polyglycolic acid into the peculiar environment of endoneurial tissues results in minimal scarring and in minimal disturbance of the surrounding nerve fibers. The material was progressively absorbed with minimal disturbance of intrafascicular structures.

scholarly journals Prof. M. N. Lapinsky. About degeneration and regeneration of peripheral nerves. - Kiev, 1904

1904 ◽  
Vol XII (4) ◽  
pp. 146-149
Author(s):  
B. Vorotynskiy
Keyword(s):  
Literature Review ◽  
Peripheral Nerve ◽  
Nerve Fiber ◽  
Experimental Research ◽  
Peripheral Nerves ◽  
Nerve Fibers

The work is divided into 4 chapters. The first chapter is devoted to a literature review of the issue of degeneration of peripheral nerve fibers. The next two chapters contain a description of the finest structure of the peripheral nerve according to the latest literature data and on the basis of the author's own observations. The last chapter presents the results of the author's experimental research on the question of the degeneration and revival of the nerve fiber in the peripheral nerve.

scholarly journals THE BEHAVIOR OF RESIDUAL AXONS IN PARTIALLY DENERVATED MUSCLES OF THE MONKEY

1951 ◽  
Vol 93 (3) ◽  
pp. 207-215 ◽  
Author(s):  
Mac V. Edds ◽  
Wilfred T. Small
Keyword(s):  
Sciatic Nerve ◽  
Nerve Fiber ◽  
Muscle Atrophy ◽  
Tibial Nerve ◽  
Histological Study ◽  
Nerve Fibers ◽  
Functional Improvement ◽  
Lumbosacral Plexus ◽  
Leg Muscles ◽  
Denervated Muscles

Leg muscles of the monkey have been studied following partial denervation produced by surgical elimination of from 25 to 90 per cent of the axons entering the sciatic nerve from the lumbosacral plexus. The investigation included observations on function, rate and degree of muscle atrophy, and neurohistological appearance of the affected muscles. In most of the cases, from 83 to 90 per cent of the residual nerve fibers in the peroneal and tibial nerves were destroyed and a severe paresis of the leg muscles was produced. No functional improvement was noted up to 160 days after operation, and the affected muscles became markedly atrophic. Histological examination of these muscles failed to reveal more than sporadic collateral regeneration of the residual axons. In two cases 50 and 75 per cent of the peroneal and tibial nerve fibers remained intact 63 and 200 days, respectively, after operation. The legs operated upon in these cases functioned almost normally and all muscles weighed within 11 per cent of those of the contralateral, normal leg. Histological study and counts of end-plate: nerve fiber ratios showed that many residual axons had regenerated collateral branches which entered denervated end-plates. Collateral regeneration was incomplete, however, and many end-plates remained without innervation. These results indicate that residual axons in paretic muscles of a primate do not regenerate collaterally as readily as do those of other previously studied mammals.

scholarly journals Effect of hyperglycemia on conduction parameters of tibial nerve’s fibers to different muscles: A rat model

2013 ◽  
Vol 04 (01) ◽  
pp. 09-12
Author(s):  
Çağdaş Erdoğan ◽  
Utku Cenikli ◽  
Eylem Değirmenci ◽  
Attila Oğuzhanoğlu
Keyword(s):  
Peripheral Nerve ◽  
Nerve Fiber ◽  
Rat Model ◽  
Gastrocnemius Muscle ◽  
Tibial Nerve ◽  
Nerve Fibers ◽  
Significant Difference ◽  
Conduction Velocities ◽  
Intrinsic Muscles

ABSTRACT Introduction: Routine conduction studies reflect the summation of all nerve fibers in a peripheral nerve. Nerve fiber groups to distal, small muscles have smaller diameters than the ones to large proximal muscles. There may be minimal differences between the diameters of nerve fiber groups innervating different muscles; even they are all same type of fibers. So, in neuropathic processes some nerve fiber groups may be more seriously affected. Materials and Methods: 14 rats ( 7 diabetic, 7 control) were studied. Tibial nerve was stimulated from two points and while recorded from a distal (foot intrinsic muscles) and a proximal (gastrocnemius) muscle. Results: There was a significant difference between the proximal and distal recorded conduction velocities. Both proximal and distal recorded conduction velocities decreased during the hyperglycemic process. Discussion: Our method successfully demonstrated different nerve fiber groups; but, the neuropathic process seemed to be homogeneous in both fiber groups.

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