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Medical & Biological Engineering &... Nov 2022Ultrasound (US) imaging is recognized as a useful support for Carpal Tunnel Syndrome (CTS) assessment through the evaluation of median nerve morphology. However, US is...
Ultrasound (US) imaging is recognized as a useful support for Carpal Tunnel Syndrome (CTS) assessment through the evaluation of median nerve morphology. However, US is still far to be systematically adopted to evaluate this common entrapment neuropathy, due to US intrinsic challenges, such as its operator dependency and the lack of standard protocols. To support sonographers, the present study proposes a fully-automatic deep learning approach to median nerve segmentation from US images. We collected and annotated a dataset of 246 images acquired in clinical practice involving 103 rheumatic patients, regardless of anatomical variants (bifid nerve, closed vessels). We developed a Mask R-CNN with two additional transposed layers at segmentation head to accurately segment the median nerve directly on transverse US images. We calculated the cross-sectional area (CSA) of the predicted median nerve. Proposed model achieved good performances both in median nerve detection and segmentation: Precision (Prec), Recall (Rec), Mean Average Precision (mAP) and Dice Similarity Coefficient (DSC) values are 0.916 ± 0.245, 0.938 ± 0.233, 0.936 ± 0.235 and 0.868 ± 0.201, respectively. The CSA values measured on true positive predictions were comparable with the sonographer manual measurements with a mean absolute error (MAE) of 0.918 mm. Experimental results showed the potential of proposed model, which identified and segmented the median nerve section in normal anatomy images, while still struggling when dealing with infrequent anatomical variants. Future research will expand the dataset including a wider spectrum of normal anatomy and pathology to support sonographers in daily practice.
Topics: Bays; Carpal Tunnel Syndrome; Deep Learning; Humans; Median Nerve; Ultrasonography; Wrist
PubMed: 36152237
DOI: 10.1007/s11517-022-02662-5 -
Sultan Qaboos University Medical Journal Feb 2017The brachial innervates the upper extremities. While variations in the formation of the brachial and its terminal branches are quite common, it is uncommon for the...
The brachial innervates the upper extremities. While variations in the formation of the brachial and its terminal branches are quite common, it is uncommon for the median nerve to innervate the muscles of the arm. During the dissection of an elderly male cadaver at the Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India, in 2016, the muscle was found to be supplied by a direct branch from the lateral root of the median nerve and the musculocutaneous nerve was absent. The branches of the median nerve supplied the biceps and muscles and the last branch continued as the lateral cutaneous nerve of the forearm. These variations may present atypically in cases of arm paralysis or sensory loss on the lateral forearm. Knowledge of these variations is important in surgeries and during the administration of regional anaesthesia near the shoulder joint and upper arm.
Topics: Aged; Brachial Plexus; Cadaver; Dissection; Forearm; Humans; Male; Median Nerve; Muscle, Skeletal; Musculocutaneous Nerve
PubMed: 28417038
DOI: 10.18295/squmj.2016.17.01.019 -
PloS One 2021Short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI) occur when the motor evoked potential (MEP) elicited by transcranial magnetic...
Short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI) occur when the motor evoked potential (MEP) elicited by transcranial magnetic stimulation (TMS) is reduced by the delivery of a preceding peripheral nerve stimulus. The intra-individual variability in SAI and LAI is considerable, and the influence of sample demographics (e.g., age and biological sex) and testing context (e.g., time of day) is not clear. There are also no established normative values for these measures, and their reliability varies from study-to-study. To address these issues and facilitate the interpretation of SAI and LAI research, we pooled data from studies published by our lab between 2014 and 2020 and performed several retrospective analyses. Patterns in the depth of inhibition with respect to age, biological sex and time of testing were investigated, and the relative reliability of measurements from studies with repeated baseline SAI and LAI assessments was examined. Normative SAI and LAI values with respect to the mean and standard deviation were also calculated. Our data show no relationship between the depth of inhibition for SAI and LAI with either time of day or age. Further, there was no significant difference in SAI or LAI between males and females. Intra-class correlation coefficients (ICC) for repeated measurements of SAI and LAI ranged from moderate (ICC = 0.526) to strong (ICC = 0.881). The mean value of SAI was 0.71 ± 0.27 and the mean value of LAI was 0.61 ± 0.34. This retrospective study provides normative values, reliability estimates, and an exploration of demographic and testing influences on these measures as assessed in our lab. To further facilitate the interpretation of SAI and LAI data, similar studies should be performed by other labs that use these measures.
Topics: Adult; Afferent Pathways; Age Factors; Evoked Potentials, Motor; Female; Healthy Volunteers; Humans; Male; Median Nerve; Middle Aged; Motor Cortex; Neural Inhibition; Reaction Time; Reproducibility of Results; Retrospective Studies; Sex Factors; Transcranial Magnetic Stimulation
PubMed: 34905543
DOI: 10.1371/journal.pone.0260663 -
Journal of Orthopaedic Surgery (Hong... 2017We aimed to compare the movement of the median nerve within the carpal tunnel during wrist and finger motions between before and after carpal tunnel release (CTR) using...
PURPOSE
We aimed to compare the movement of the median nerve within the carpal tunnel during wrist and finger motions between before and after carpal tunnel release (CTR) using transverse ultrasound in carpal tunnel syndrome (CTS) patients and to evaluate the biomechanical efficacy of CTR for CTS.
METHODS
Twenty-four patients with CTS were examined by transverse ultrasound. The location of the median nerve within the carpal tunnel was examined quantitatively as a coordinate at varied wrist positions with finger extension and flexion, respectively, before and after CTR.
RESULTS
We found that the median nerve moved statistically significantly more palmarly after CTR than before at all wrist positions during finger motion. The average median nerve displacement toward the palmar side at the palmar flexion position in finger flexion was the greatest among all positions. Additionally, the displacement amounts of the median nerve during finger motion at all wrist positions were statistically significantly smaller after CTR than before.
CONCLUSIONS
The current study demonstrated the movement patterns of the median nerve in the carpal tunnel during wrist and finger motions compared before and after CTR using transverse ultrasound in CTS patients. The findings suggested that as the median nerve shifted greatly palmarly away from the tendons after CTR, the nerve avoids compression or shearing stress from the tendons. This ultrasound information could offer further understanding of the pathomechanics of CTS and provide a more accurate diagnosis of CTS and better treatment by CTR.
Topics: Adult; Carpal Tunnel Syndrome; Female; Fingers; Humans; Male; Median Nerve; Middle Aged; Movement; Range of Motion, Articular; Stress, Mechanical; Tendons; Ultrasonography; Wrist Joint
PubMed: 28920545
DOI: 10.1177/2309499017730422 -
Turkish Neurosurgery 2021To study topography and variability in the origin of anterior interosseous nerve; to identify the branching pattern of the anterior interosseous nerve supplying the...
AIM
To study topography and variability in the origin of anterior interosseous nerve; to identify the branching pattern of the anterior interosseous nerve supplying the flexor digitorum profundus, flexor pollicis longus, and pronator quadratus muscles.
MATERIAL AND METHODS
The present study included 70 formalin-fixed upper limbs of adult human cadavers. The origin of the anterior interosseous nerve was categorized into 3 types. The morphometric data obtained in this study were represented as mean± SD and the dimensions were given in millimeter. The measurements were compared statistically by using 'EZR software, version 1.38, 2019'. The 'paired t-test' was applied and the 'p' value less than 0.05 was considered as statistically significant.
RESULTS
It was observed that the origin of the anterior interosseous nerve was extremely variable. It was ranging from the midepicondylar point of the elbow joint up to as below as 86mm from it. The distance of its origin from the midpoint of the pronator teres muscle ranged between 70 mm above the pronator teres muscle to 22 mm below it. In one of the forearms, the median nerve supplied the medial two tendons of the FDP, instead of the ulnar nerve.
CONCLUSION
The present study provided additional information about the origin, topography, and distribution of the anterior interosseous nerve. The data will provide further insight into the causes of nerve compression syndromes. It will also help in planning the surgical approach into the distal humerus, elbow joint, and proximal ends of radius and ulna, without causing any nerve injury.
Topics: Adult; Cadaver; Cross-Sectional Studies; Female; Forearm; Hand; Humans; Male; Median Nerve; Muscle, Skeletal; Nerve Compression Syndromes
PubMed: 33372256
DOI: 10.5137/1019-5149.JTN.29917-20.2 -
Journal of Physiological Anthropology Aug 2019High-resolution ultrasound is being widely used in carpal tunnel examination to understand morphological and biomechanical characteristics of the median nerve and...
BACKGROUND
High-resolution ultrasound is being widely used in carpal tunnel examination to understand morphological and biomechanical characteristics of the median nerve and surrounding anatomy structures.
MAIN BODY
Healthy young and elderly men were recruited. The median nerve at proximal wrist region was examined by ultrasound imaging technique. A total of seven wrist angle was examined. Generally, the median nerve cross-sectional area of the elderly group is significantly larger than the young group.
SHORT CONCLUSION
Wrist posture in greater flexion or extension caused a larger decrease in the median nerve cross-sectional area across both groups.
Topics: Adult; Aged; Aging; Hand; Humans; Male; Median Nerve; Posture; Ultrasonography; Wrist; Young Adult
PubMed: 31395098
DOI: 10.1186/s40101-019-0201-6 -
Journal of Ultrasound Dec 2017Peripheral nerves frequently travel close to the bone surface and are, therefore, prone to elastosonographic "bone-proximity" hardening artifacts. The impact of these...
PURPOSE
Peripheral nerves frequently travel close to the bone surface and are, therefore, prone to elastosonographic "bone-proximity" hardening artifacts. The impact of these artifacts on quantitative measurements of median nerve stiffness performed by shear wave elastosonography has not been explored. Our aim was to assess normal median nerve stiffness values at various locations.
MATERIALS AND METHODS
Thirty-six healthy volunteers (24 women and 12 men) aged between 25 and 40 years were evaluated. Two operators performed the evaluation: one expert (6 years of ultrasound experience) and one inexperienced operator (6 months' experience). The nerve was sampled in cross-section at three different locations: mid-forearm, immediately before the carpal tunnel and within the tunnel. The ultrasound scanner was equipped with a 14-MHz linear probe. The Shear Wave module was activated in one-shot mode. Measurements were performed using a ROI corresponding to the diameter of the nerve.
RESULTS
The mean values of stiffness of the medial nerve were 32.26 kPa ± 18.60 within the carpal tunnel, 22.20 kPa ± 9.84 at the carpal tunnel inlet and 7.62 kPa ± 7.38 in the forearm. Inter-observer agreement assessed using the intraclass correlation coefficient (ICC) was "moderate" within the carpal tunnel (ICC = 0.44), "moderate" at the carpal tunnel inlet (ICC = 0.41) and "fair" in the forearm (ICC = 0.38).
CONCLUSIONS
The stiffness of the median nerve progressively increases in its distal portions, where the nerve approaches the bone surface. Inter-observer agreement was generally good (from fair to moderate).
Topics: Adult; Artifacts; Bone and Bones; Elasticity; Elasticity Imaging Techniques; Female; Humans; Male; Median Nerve; Observer Variation; Organ Size; Professional Competence
PubMed: 29204233
DOI: 10.1007/s40477-017-0267-0 -
Archives of Orthopaedic and Trauma... May 2022Preventing nerve injury is critical in elbow surgery. Distal extension of medial approaches, required for coronoid fracture fixation and graft-replacement, may endanger...
INTRODUCTION
Preventing nerve injury is critical in elbow surgery. Distal extension of medial approaches, required for coronoid fracture fixation and graft-replacement, may endanger the median nerve. This study aims to describe an easily identifiable and reproducible anatomical landmark to localize the median nerve distal to the joint line and to delineate how its relative position changes with elbow flexion and forearm rotation.
MATERIALS AND METHODS
The median nerve and the ulnar insertion of the brachialis muscle were identified in eleven fresh-frozen cadaveric specimens after dissection over an extended medial approach. The elbow was brought first in full extension and then in 90° flexion, and the shortest distance between the two structures was measured while rotating the forearm in full pronation, neutral position and full supination.
RESULTS
The distance between the median nerve and the brachialis insertion was highest with the elbow flexed and the forearm in neutral position. All distances measured in flexion were larger than those in extension, and all distances measured from the most proximal point of the brachialis insertion were larger than those from the most distal point. Distances in pronation and in supination were smaller than to those in neutral forearm position.
CONCLUSIONS
The ulnar insertion of the brachialis is a reliable landmark to localize and protect the median nerve at the level of the coronoid base. Elbow flexion and neutral forearm position increase significantly the safety margins between the two structures; this information suggests some modifications to the previously described medial elbow approaches.
LEVEL OF EVIDENCE
Basic Science Study.
Topics: Cadaver; Elbow; Elbow Joint; Forearm; Humans; Median Nerve; Muscle, Skeletal; Ulna
PubMed: 33484309
DOI: 10.1007/s00402-021-03753-y -
Scandinavian Journal of Work,... Mar 2017Objectives The aim of this study was to evaluate the development of impaired median nerve function in relation to hand-intensive seasonal work. We hypothesized that at...
Objectives The aim of this study was to evaluate the development of impaired median nerve function in relation to hand-intensive seasonal work. We hypothesized that at end-season, median nerve conduction would be impaired and then recover within weeks. Methods Using nerve conduction studies (NCS), we examined median nerve conduction before, during, and after engaging in 22 days of mink skinning. For a subgroup, we used goniometry and surface electromyography to characterize occupational mechanical exposures. Questionnaire information on symptoms, disability, and lifestyle factors was obtained. Results The study comprised 11 male mink skinners with normal median nerve conduction at pre-season (mean age 35.7 years, mean number of seasons with skinning 8.9 years). Mink skinning was characterized by a median angle of wrist flexion/extension of 16º extension, a median velocity of wrist flexion/extension of 22 °/s, and force exertions of 11% of maximal voluntary electrical activity. At end-season, mean distal motor latency (DML) had increased 0.41 ms (P<0.001), mean sensory nerve conduction velocity (SNCV) digit 2 had decreased 6.3 m/s (P=0.004), and mean SNCV digit 3 had decreased 6.2 m/s (P=0.01); 9 mink skinners had decreases in nerve conduction, 5 fulfilled electrodiagnostic criteria and 4 fulfilled electrodiagnostic and clinical criteria (a positive Katz hand diagram) for carpal tunnel syndrome (CTS). Three to six weeks post-season, the changes had reverted to normal. Symptom and disability scores showed corresponding changes. Conclusions In this natural experiment, impaired median nerve conduction developed during 22 days of repetitive industrial work with moderate wrist postures and limited force exertion. Recovery occurred within 3-6 weeks post-season.
Topics: Carpal Tunnel Syndrome; Electromyography; Hand; Humans; Median Nerve; Neural Conduction; Occupational Exposure; Wrist
PubMed: 28060387
DOI: 10.5271/sjweh.3619 -
Clinical Neurophysiology : Official... Apr 2020To establish a noninvasive method to measure the neuromagnetic fields of the median nerve at the carpal tunnel after electrical digital nerve stimulation and evaluate...
OBJECTIVE
To establish a noninvasive method to measure the neuromagnetic fields of the median nerve at the carpal tunnel after electrical digital nerve stimulation and evaluate peripheral nerve function.
METHODS
Using a vector-type biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields at the carpal tunnel were recorded after electrical stimulation of the index or middle digital nerve in five healthy volunteers. A novel technique for removing stimulus-induced artifacts was applied, and current distributions were calculated using a spatial filter algorithm and superimposed on X-ray.
RESULTS
A neuromagnetic field propagating from the palm to the carpal tunnel was observed in all participants. Current distributions estimated from the magnetic fields had five components: leading and trailing components parallel to the conduction pathway, outward current preceding the leading component, inward currents between the leading and trailing components, and outward current following the trailing component. The conduction velocity and peak latency of the inward current agreed well with those of sensory nerve action potentials.
CONCLUSION
Removing stimulus-induced artifacts enabled magnetoneurography to noninvasively visualize with high spatial resolution the electrophysiological neural activity from the palm to the carpal tunnel.
SIGNIFICANCE
This is the first report of using magnetoneurography to visualize electrophysiological nerve activity at the palm and carpal tunnel.
Topics: Action Potentials; Adult; Carpal Tunnel Syndrome; Electric Stimulation; Female; Hand; Humans; Magnetic Fields; Male; Median Nerve; Neural Conduction
PubMed: 31866341
DOI: 10.1016/j.clinph.2019.11.030