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BioMed Research International 2017. The purpose of this study was to assess nerve hypervascularization using high resolution ultrasonography to determine the effects of wrist posture and fingertip force... (Clinical Trial)
Clinical Trial
. The purpose of this study was to assess nerve hypervascularization using high resolution ultrasonography to determine the effects of wrist posture and fingertip force on median nerve blood flow at the wrist in healthy participants and those experiencing carpal tunnel syndrome (CTS) symptoms. . The median nerves of nine healthy participants and nine participants experiencing symptoms of CTS were evaluated using optimized ultrasonography in five wrist postures with and without a middle digit fingertip press (0, 6 N). . Both wrist posture and fingertip force had significant main effects on mean peak blood flow velocity. Blood flow velocity with a neutral wrist (2.87 cm/s) was significantly lower than flexed 30° (3.37 cm/s), flexed 15° (3.27 cm/s), and extended 30° (3.29 cm/s). Similarly, median nerve blood flow velocity was lower without force (2.81 cm/s) than with force (3.56 cm/s). A significant difference was not found between groups. . Vascular changes associated with CTS may be acutely induced by nonneutral wrist postures and fingertip force. This study represents an early evaluation of intraneural blood flow as a measure of nerve hypervascularization in response to occupational risk factors and advances our understanding of the vascular phenomena associated with peripheral nerve compression.
Topics: Adult; Blood Flow Velocity; Carpal Tunnel Syndrome; Female; Fingers; Humans; Male; Median Nerve; Middle Aged; Muscle Strength; Posture; Wrist
PubMed: 28286771
DOI: 10.1155/2017/7156489 -
Neurosciences (Riyadh, Saudi Arabia) Jul 2017One of the most common referrals to the electrodiagnostic (EDX) laboratory is to confirm a clinical impression of carpal tunnel syndrome (CTS). The EDX studies are... (Review)
Review
One of the most common referrals to the electrodiagnostic (EDX) laboratory is to confirm a clinical impression of carpal tunnel syndrome (CTS). The EDX studies are valuable in localizing median nerve abnormalities to the wrist, grading its severity, and excluding other condition that can mimic or coexist with CTS. However, there are many clinical and EDX pitfalls that can lead to misdiagnosis. Careful clinical assessment and attention to technical factors and details of the EDX techniques are fundamental for the quality and accurate interpretation of the study. This review aims to discuss the clinical and the EDX approaches to the diagnosis of CTS with emphasis on the commonly encountered pitfalls.
Topics: Carpal Tunnel Syndrome; Diagnostic Techniques, Neurological; Humans; Median Nerve
PubMed: 28678210
DOI: 10.17712/nsj.2017.3.20160638 -
BMC Musculoskeletal Disorders Nov 2017Systemic sclerosis can affect peripheral nerves, but the extent and the nature of this involvement are not well defined. The aim of this study is to compare the...
BACKGROUND
Systemic sclerosis can affect peripheral nerves, but the extent and the nature of this involvement are not well defined. The aim of this study is to compare the sonoelastrographic measurements of median nerves in systemic sclerosis (SSC), idiopathic carpal tunnel syndrome (CTS) and healthy individuals.
METHODS
The clinical, electrophysiological and ultrasonographic assessments were done. Patients with SSC and CTS were assessed with nerve conduction studies. The measurements of cross sectional areas (CSA) were performed at psiform and forearm level from axial US images. The elastic ratio is the ratio of strain distribution in two selected region of interests (ROI) done via comparing the median nerve to flexor digitorum superfcialis tendon. The ROIs were fixed to 2 mm.
RESULTS
The study was completed with 47 hands of 24 patients with SSC, 53 hands of 27 patients with CTS and 38 hands of health controls. The CSA of CTS group was significantly higher than systemic sclerosis and control groups. The elastic ratio at psiform level and forearm levels of systemic sclerosis group were significantly higher than the CTS and control groups.
CONCLUSION
Median nerves lose the elasticity while the CSA's are in the normal range in patients with SSC. These results suggested that the increased peripheral nerve involvement in SSC is about the increased stiffness of the nerves.
Topics: Carpal Tunnel Syndrome; Case-Control Studies; Elasticity; Elasticity Imaging Techniques; Female; Humans; Male; Median Nerve; Scleroderma, Systemic
PubMed: 29115959
DOI: 10.1186/s12891-017-1793-9 -
Orthopaedics & Traumatology, Surgery &... Apr 2021Several structures liable to compress the median nerve have been described around the elbow and proximal forearm. Signs of deficit justify surgical exploration and...
INTRODUCTION
Several structures liable to compress the median nerve have been described around the elbow and proximal forearm. Signs of deficit justify surgical exploration and decompression by exoneurolysis. Better knowledge of the locations of these structures would ensure reliable and effective exploration.
HYPOTHESIS
The study hypothesis was that compressive structures show precise topography, with few variations in distance along the median nerve course.
MATERIAL AND METHODS
The study was performed on 36 upper-limb cadaver specimens. The measurement reference level was the humeral bi-epicondylar line. Proximal-to-distal dissection located: (1) Struthers' ligament, (2) the pronator teres bellies (PT) with their anatomic particularities of structure and insertion, (3) the lacertus fibrosus, (4) the fibrous arcade of the flexor digitorum superficialis (FDS), (5) the accessory muscles, (6) the origin of the anterior interosseous nerve (AIN), (7) and the vascular arches.
RESULTS
Struthers' ligament was not located, but 1 case of medial bicipital fibrous arcade was found. The lacertus fibrosus crossed the median nerve at +1.5±0.6cm. PT insertion was high in 19 cases (53%). The humeral PT belly was thin in 21 cases (58%), crossing the median nerve more distally (+1.8±0.8cm) than the thicker muscles (+1±1.1cm) (p=0.016). The ulnar PT belly was fibrous in 14 cases (39%). A fibrous arcade was found between the 2 PT bellies in 23 cases (64%). The FDS arcade was located at 4.5-7cm from the bi-epicondylar line. An accessory flexor pollicis longus belly was found in 11% of cases. The AIN origin was at +4±1.6cm from the reference. A vascular pedicle crossed the median nerve in 3 cases.
DISCUSSION
The present study inventoried and mapped 6 potentially compressive structures neighboring or crossing the median nerve. Except for the FDS arcade, they showed very precise proximal-to-distal location, with variations of 0.5 to 1.5cm.
LEVEL OF EVIDENCE
IV; case series.
Topics: Cadaver; Elbow; Elbow Joint; Forearm; Humans; Median Nerve; Muscle, Skeletal; Tendons
PubMed: 33482406
DOI: 10.1016/j.otsr.2021.102813 -
Scientific Reports Sep 2020There are conflicting hypotheses regarding the initial pathogenesis of carpal tunnel syndrome (CTS). One hypothesis characterizes it as inflammation of the median nerve...
There are conflicting hypotheses regarding the initial pathogenesis of carpal tunnel syndrome (CTS). One hypothesis characterizes it as inflammation of the median nerve caused by compression, while another hypothesis characterizes CTS as non-inflammatory fibrosis of the subsynovial connective tissue (SSCT). This study aimed to investigate the differences in the ultrasonography parameters before and after a steroid injection, which is effective for CTS, to elucidate the initial pathogenesis of CTS and the mechanisms of action of the injected steroid. Fourteen hands from 14 healthy participants and 24 hands from 24 participants with mild CTS were examined. Dynamic movement and morphology of the median nerve before and after steroid injection were measured. There was no significant difference in the normalized maximal distance of the median nerve, which reflects the degree of fibrosis in the SSCT indirectly, during finger and wrist movements before and after the injection among patients with CTS (p > 0.05). Among the parameters that indirectly reflects the degree of median nerve compression, such as normalized maximal change in the aspect ratio of the minimum-enclosing rectangle (MER), maximal change in the median nerve perimeter, and maximal value of the median nerve cross-sectional area (CSA), statistically significant differences were not observed between values of the normalized maximal change in the aspect ratio of the MER and maximal change in the median nerve perimeter, during finger and wrist movements recorded before and after the injection in patients with CTS (p > 0.05). However, multivariate logistic regression analysis revealed that the change in the normalized maximal value of the median nerve CSA, according to finger and wrist movement was correlated with the administration of the steroid injection (p < 0.05). In conclusion, compared to that noted before steroid injection, the median nerve CSA noted during finger and wrist movements changed significantly after injection in patients with mild CTS. Given the improvement in median nerve swelling after steroid injection, but no improvement in the movement of the median nerve during finger and wrist movements, median nerve swelling due to compression (rather than fibrosis of the SSCT may be the initial pathogenesis of early-stage (mild) CTS, and the fibrous changes around the median nerves (SSCT) may be indicative of secondary pathology after median nerve compression. Further studies are required to validate the findings of our study and confirm the pathogenesis of CTS.
Topics: Aged; Carpal Tunnel Syndrome; Cross-Sectional Studies; Female; Humans; Injections; Male; Median Nerve; Middle Aged; Movement; Steroids; Ultrasonography; Wrist
PubMed: 32973181
DOI: 10.1038/s41598-020-72757-2 -
Neurology India 2021
Topics: Hamartoma; Humans; Lipoma; Median Nerve; Ulnar Nerve
PubMed: 33642316
DOI: 10.4103/0028-3886.310107 -
Muscle & Nerve Sep 2017In this study we provide detailed quantification of upper extremity nerve and fascicular anatomy. The purpose is to provide values and trends in neural features useful...
INTRODUCTION
In this study we provide detailed quantification of upper extremity nerve and fascicular anatomy. The purpose is to provide values and trends in neural features useful for clinical applications and neural interface device design.
METHODS
Nerve cross-sections were taken from 4 ulnar, 4 median, and 3 radial nerves from 5 arms of 3 human cadavers. Quantified nerve features included cross-sectional area, minor diameter, and major diameter. Fascicular features analyzed included count, perimeter, area, and position.
RESULTS
Mean fascicular diameters were 0.57 ± 0.39, 0.6 ± 0.3, 0.5 ± 0.26 mm in the upper arm and 0.38 ± 0.18, 0.47 ± 0.18, 0.4 ± 0.27 mm in the forearm of ulnar, median, and radial nerves, respectively. Mean fascicular diameters were inversely proportional to fascicle count.
CONCLUSION
Detailed quantitative anatomy of upper extremity nerves is a resource for design of neural electrodes, guidance in extraneural procedures, and improved neurosurgical planning. Muscle Nerve 56: 463-471, 2017.
Topics: Arm; Cadaver; Female; Humans; Male; Median Nerve; Peripheral Nerves; Radial Nerve; Ulnar Nerve; Upper Extremity
PubMed: 28006854
DOI: 10.1002/mus.25534 -
Clinical Neurophysiology : Official... Nov 2019To visualize neural activity in the brachial plexus using magnetoneurography (MNG).
OBJECTIVE
To visualize neural activity in the brachial plexus using magnetoneurography (MNG).
METHODS
Using a 124- or 132-channel biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields above the clavicle and neck region were recorded in response to electrical stimulation of the median and ulnar nerves in five asymptomatic volunteers (four men and one woman; age, 27-45 years old). Equivalent currents were computationally reconstructed from neuromagnetic fields and visualized as pseudocolor maps. Reconstructed currents at the depolarization site and compound nerve action potentials (CNAPs) at Erb's point were compared.
RESULTS
Neuromagnetic fields were recorded in all subjects. The reconstructed equivalent currents propagated into the vertebral foramina, and the main inflow levels differed between the median nerve (C5/C6-C7/T1 vertebral foramen) and the ulnar nerve (C7/T1-T1/T2). The inward current peaks at the depolarization site and CNAPs showed high linear correlation.
CONCLUSIONS
MNG visualizes neural activity in the brachial plexus and can differentiate the conduction pathways after median and ulnar nerve stimulations. In addition, it can visualize not only the leading and trailing components of intra-axonal currents, but also inward currents at the depolarization site.
SIGNIFICANCE
MNG is a novel and promising functional imaging modality for the brachial plexus.
Topics: Action Potentials; Adult; Brachial Plexus; Electric Stimulation; Female; Humans; Magnetic Fields; Magnetometry; Male; Median Nerve; Middle Aged; Neural Conduction; Neurons; Ulnar Nerve
PubMed: 31542709
DOI: 10.1016/j.clinph.2019.08.006 -
Arthritis Research & Therapy Feb 2022Deep learning applied to ultrasound (US) can provide a feedback to the sonographer about the correct identification of scanned tissues and allows for faster and...
BACKGROUND
Deep learning applied to ultrasound (US) can provide a feedback to the sonographer about the correct identification of scanned tissues and allows for faster and standardized measurements. The most frequently adopted parameter for US diagnosis of carpal tunnel syndrome is the increasing of the cross-sectional area (CSA) of the median nerve. Our aim was to develop a deep learning algorithm, relying on convolutional neural networks (CNNs), for the localization and segmentation of the median nerve and the automatic measurement of its CSA on US images acquired at the proximal inlet of the carpal tunnel.
METHODS
Consecutive patients with rheumatic and musculoskeletal disorders were recruited. Transverse US images were acquired at the carpal tunnel inlet, and the CSA was manually measured. Anatomical variants were registered. The dataset consisted of 246 images (157 for training, 40 for validation, and 49 for testing) from 103 patients each associated with manual annotations of the nerve boundary. A Mask R-CNN, state-of-the-art CNN for image semantic segmentation, was trained on this dataset to accurately localize and segment the median nerve section. To evaluate the performances on the testing set, precision (Prec), recall (Rec), mean average precision (mAP), and Dice similarity coefficient (DSC) were computed. A sub-analysis excluding anatomical variants was performed. The CSA was automatically measured by the algorithm.
RESULTS
The algorithm correctly identified the median nerve in 41/49 images (83.7%) and in 41/43 images (95.3%) excluding anatomical variants. The following metrics were obtained (with and without anatomical variants, respectively): Prec 0.86 ± 0.33 and 0.96 ± 0.18, Rec 0.88 ± 0.33 and 0.98 ± 0.15, mAP 0.88 ± 0.33 and 0.98 ± 0.15, and DSC 0.86 ± 0.19 and 0.88 ± 0.19. The agreement between the algorithm and the sonographer CSA measurements was excellent [ICC 0.97 (0.94-0.98)].
CONCLUSIONS
The developed algorithm has shown excellent performances, especially if excluding anatomical variants. Future research should aim at expanding the US image dataset including a wider spectrum of normal anatomy and pathology. This deep learning approach has shown very high potentiality for a fully automatic support for US assessment of carpal tunnel syndrome.
Topics: Carpal Tunnel Syndrome; Humans; Median Nerve; Neural Networks, Computer; Ultrasonography; Wrist
PubMed: 35135598
DOI: 10.1186/s13075-022-02729-6 -
Brain Topography Sep 2018Paired-pulse depression (PPD) has been widely used to investigate the functional profiles of somatosensory cortical inhibition. However, PPD induced by somatosensory...
Paired-pulse depression (PPD) has been widely used to investigate the functional profiles of somatosensory cortical inhibition. However, PPD induced by somatosensory stimulation is variable, and the reasons for between- and within-subject PPD variability remains unclear. Therefore, the purpose of this study was to clarify the factors influencing PPD variability induced by somatosensory stimulation. The study participants were 19 healthy volunteers. First, we investigated the relationship between the PPD ratio of each component (N20m, P35m, and P60m) of the somatosensory magnetic field, and the alpha, beta, and gamma band changes in power [event-related desynchronization (ERD) and event-related synchronization (ERS)] induced by median nerve stimulation. Second, because brain-derived neurotrophic factor (BDNF) gene polymorphisms reportedly influence the PPD ratio, we assessed whether BDNF genotype influences PPD ratio variability. Finally, we evaluated the test-retest reliability of PPD and the alpha, beta, and gamma ERD/ERS induced by somatosensory stimulation. Significant positive correlations were observed between the P60m_PPD ratio and beta power change, and the P60m_PPD ratio was significantly smaller for the beta ERD group than for the beta ERS group. P35m_PPD was found to be robust and highly reproducible; however, P60m_PPD reproducibility was poor. In addition, the ICC values for alpha, beta, and gamma ERD/ERS were 0.680, 0.760, and 0.552 respectively. These results suggest that the variability of PPD for the P60m deflection may be influenced by the ERD/ERS magnitude, which is induced by median nerve stimulation.
Topics: Adult; Brain-Derived Neurotrophic Factor; Cortical Synchronization; Electric Stimulation; Electrophysiological Phenomena; Evoked Potentials, Somatosensory; Female; Genotype; Healthy Volunteers; Humans; Magnetoencephalography; Male; Median Nerve; Polymerase Chain Reaction; Polymorphism, Genetic; Reproducibility of Results; Somatosensory Cortex; Young Adult
PubMed: 29737438
DOI: 10.1007/s10548-018-0648-5