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Journal of Orthopaedic Research :... Mar 2021Carpal tunnel syndrome (CTS) is a peripheral neuropathy resulting from chronic median nerve compression. Chronic compression leads to neurological changes that are...
Carpal tunnel syndrome (CTS) is a peripheral neuropathy resulting from chronic median nerve compression. Chronic compression leads to neurological changes that are quantified through nerve conduction studies (NCS). Although NCS represents the gold standard in CTS assessment, they provide limited prognostic value. Several studies have identified ultrasound as a tool in diagnosing and potentially predicting the progression of CTS in patients. The purpose of this study was to evaluate the predictive value of ultrasound examination in CTS patients. Twenty patients recruited at their first visit with the neurologist completed two NCS and ultrasound examinations approximately 6 months apart. Ultrasound examination consisted of B-mode, pulse-wave Doppler and colour Doppler ultrasound videos and images to quantify median nerve cross-sectional area, intraneural blood flow velocity in three wrist postures (15° flexion, neutral, and 30° extension), and displacement of the flexor digitorum superficialis (FDS) tendon and the adjacent subsynovial connective tissue (SSCT) of the middle finger during repetitive finger flexion-extension cycles. A questionnaire was administered to assess the work-relatedness of CTS. Linear regression analyses revealed that intraneural blood flow velocity (R = 0.36, p = .03), assessed in wrist flexion, and relative FDS-SSCT displacement (R = 0.27, p = .04) and shear strain index (R = 0.28, p = .04) were significant predictors of nerve sensory and motor changes at 6 months. Results suggest the possibility of using a battery of ultrasound measures as viable markers to predict median nerve functional changes within 6 months.
Topics: Adult; Aged; Blood Flow Velocity; Carpal Tunnel Syndrome; Disease Progression; Double-Blind Method; Female; Humans; Male; Median Nerve; Middle Aged; Predictive Value of Tests; Tendons; Ultrasonography
PubMed: 33098574
DOI: 10.1002/jor.24893 -
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 -
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 -
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 -
PloS One 2022This study investigated how peripheral axonal excitability changes in ischemic stroke patients with hemiparesis or hemiplegia, reflecting the plasticity of motor axons...
OBJECTIVE
This study investigated how peripheral axonal excitability changes in ischemic stroke patients with hemiparesis or hemiplegia, reflecting the plasticity of motor axons due to corticospinal tract alterations along the poststroke stage.
METHODS
Each subject received a clinical evaluation, nerve conduction study, and nerve excitability test. Nerve excitability tests were performed on motor median nerves in paretic and non-paretic limbs in the acute stage of stroke. Control nerve excitability test data were obtained from age-matched control subjects. Some patients underwent excitability examinations several times in subacute or chronic stages.
RESULTS
A total of thirty patients with acute ischemic stroke were enrolled. Eight patients were excluded due to severe entrapment neuropathy in the median nerve. The threshold current for 50% compound muscle action potential (CMAP) was higher in paretic limbs than in control subjects. Furthermore, in the cohort with severe patients (muscle power ≤ 3/5 in affected hands), increased threshold current for 50% CMAP and reduced subexcitability were noted in affected limbs than in unaffected limbs. In addition, in the subsequent study of those severe patients, threshold electrotonus increased in the hyperpolarization direction: TEh (100-109 ms), and the minimum I/V slope decreased. The above findings suggest the less excitable and less accommodation in lower motor axons in the paretic limb caused by ischemic stroke.
CONCLUSION
Upper motor neuron injury after stroke can alter nerve excitability in lower motor neurons, and the changes are more obvious in severely paretic limbs. The accommodative changes of axons progress from the subacute to the chronic stage after stroke. Further investigation is necessary to explore the downstream effects of an upper motor neuron insult in the peripheral nerve system.
Topics: Action Potentials; Axons; Humans; Ischemic Stroke; Median Nerve; Neuronal Plasticity; Stroke
PubMed: 36194586
DOI: 10.1371/journal.pone.0275450 -
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 -
Biomedical Papers of the Medical... Dec 2009In our work we present and describe the variation of the course of the median nerve found in both upper limbs of one of the cadavers in our Institute of Anatomy (Medical...
AIMS AND METHODS
In our work we present and describe the variation of the course of the median nerve found in both upper limbs of one of the cadavers in our Institute of Anatomy (Medical Faculty, Comenius University, Bratislava, Slovakia) during the students' dissection of the peripheral nerves and vessels.
RESULTS AND CONCLUSION
This non-standard course of the median nerve was compared with a standard course described in the anatomical literature and atlases, and confronted with the variations of the median nerve found and its course described in the available literature. We also provide some clinical implications of such peripheral nerve variability because understanding such anomalies is important in the diagnosis of unexplained clinical signs and symptoms as well as during nerve blocks and certain surgical procedures around the neck and proximal arm.
Topics: Cadaver; Humans; Male; Median Nerve; Middle Aged
PubMed: 20208972
DOI: 10.5507/bp.2009.052 -
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 -
Turkish Neurosurgery 2011Carpal tunnel syndrome (CTS) is a common focal peripheral neuropathy. Increased pressure in the carpal tunnel results in median nerve compression and impaired nerve... (Review)
Review
Carpal tunnel syndrome (CTS) is a common focal peripheral neuropathy. Increased pressure in the carpal tunnel results in median nerve compression and impaired nerve perfusion, leading to discomfort and paresthesia in the affected hand. Surgical division of the transverse carpal ligament is preferred in severe cases of CTS and should be considered when conservative measures fail. A through knowledge of the normal and variant anatomy of the median nerve in the wrist is fundamental in avoiding complications during carpal tunnel release. This paper aims to briefly review the anatomic variations of the median nerve in the carpal tunnel and its implications in carpal tunnel surgery.
Topics: Carpal Bones; Carpal Joints; Carpal Tunnel Syndrome; Fingers; Hand; Humans; Median Nerve; Neurosurgical Procedures
PubMed: 21845577
DOI: 10.5137/1019-5149.JTN.3073-10.1 -
Lumbrical Muscles Neural Branching Patterns: A Cadaveric Study With Potential Clinical Implications.Hand (New York, N.Y.) Sep 2022Lumbrical muscles originate in the palm from the 4 tendons of the flexor digitorum profundus and course distally along the radial side of the corresponding...
BACKGROUND
Lumbrical muscles originate in the palm from the 4 tendons of the flexor digitorum profundus and course distally along the radial side of the corresponding metacarpophalangeal joints, in front of the deep transverse metacarpal ligament. The first and second lumbrical muscles are typically innervated by the median nerve, and third and fourth by the ulnar nerve. A plethora of lumbrical muscle variants has been described, ranging from muscles' absence to reduction in their number or presence of accessory slips. The current cadaveric study highlights typical and variable neural supply of lumbrical muscles.
MATERIALS
Eight (3 right and 5 left) fresh frozen cadaveric hands of 3 males and 5 females of unknown age were dissected. From the palmar wrist crease, the median and ulnar nerve followed distally to their terminal branches. The ulnar nerve deep branch was dissected and lumbrical muscle innervation patterns were noted.
RESULTS
The frequency of typical innervations of lumbrical muscles is confirmed. The second lumbrical nerve had a double composition from both the median and ulnar nerves, in 12.5% of the hands. The thickest branch (1.38 mm) originated from the ulnar nerve and supplied the third lumbrical muscle, and the thinnest one (0.67 mm) from the ulnar nerve and supplied the fourth lumbrical muscle. In 54.5%, lumbrical nerve bifurcation was identified.
CONCLUSION
The complex innervation pattern and the peculiar anatomy of branching to different thirds of the muscle bellies are pointed out. These findings are important in dealing with complex and deep injuries in the palmar region, including transmetacarpal amputations.
Topics: Cadaver; Female; Hand; Humans; Male; Median Nerve; Muscle, Skeletal; Ulnar Nerve
PubMed: 33349041
DOI: 10.1177/1558944720963881