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Journal of Ultrasound Sep 2020Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy of peripheral nerves, with an incidence of 1-3 patients in 1000. CTS typically occurs between 45... (Review)
Review
Carpal tunnel syndrome (CTS) is the most frequent entrapment neuropathy of peripheral nerves, with an incidence of 1-3 patients in 1000. CTS typically occurs between 45 and 60 years of age, and it is more frequent in women than in men. The main cause of CTS is chronic compression of the median nerve and ischemic suffering secondary to increased pressure in the carpal tunnel. There are many possible causes of CTS, which can be differentiated into idiopathic causes, which include most cases, and secondary causes. Classical CTS diagnosis is based on the patient's clinical examination and electrophysiological tests, such as electromyography and nerve conduction studies. The latter are helpful for determining the site of nerve compression, assessing its severity, monitoring the course of the disease after therapy, and excluding other causes of median nerve pain, such as cervical radiculopathies, brachial plexopathies, polyneuropathy, or other forms of mononeuropathies. However, clinical examination and electrophysiological tests are not able to differentiate idiopathic forms from secondary forms of CTS, and discrepancies are possible between clinical examination and electrophysiological tests (false negatives). Ultrasound examination is able to recognize most of the secondary forms of CTS. It can evaluate the morphological alterations of the nerve and correlate them with the severity of nerve suffering in all cases, even idiopathic ones, with a sensitivity and specificity equal to those of electrophysiological tests. It can also highlight some anatomical predisposing variants or conditions that may represent contraindications to minimally invasive treatments. Ultrasound examination also plays a fundamental role in evaluating patients with an unfavorable outcome after surgical treatment.
Topics: Carpal Tunnel Syndrome; Humans; Median Nerve; Ultrasonography
PubMed: 32323256
DOI: 10.1007/s40477-020-00460-z -
Clinical Biomechanics (Bristol, Avon) Jan 2020Carpal tunnel and median nerve dynamically change with wrist motion. The purpose of this study was to investigate the morphological changes and positional migration of...
BACKGROUND
Carpal tunnel and median nerve dynamically change with wrist motion. The purpose of this study was to investigate the morphological changes and positional migration of the carpal arch and median nerve, as well as nerve-arch positional relationship associated with wrist deviation in healthy volunteers.
METHODS
Twenty asymptomatic male volunteers performed wrist motion from neutral to deviated positions combining flexion-extension and radioulnar deviation. Ultrasound images of the carpal arch and median nerve at the distal carpal tunnel were collected during wrist motion. Morphological and positional parameters of the carpal arch and median nerve were derived from the ultrasound images.
FINDINGS
Carpal arch height, area, and palmar bowing of the transverse carpal ligament (TCL) increased with flexion related wrist motion and decreased with extension related motion (P < 0.05). Arch width increased with radial flexion and decreased with extension and ulnar extension (P < 0.05). Median nerve circularity increased with flexion and radial flexion but decreased with extension, ulnar extension, and ulnar deviation (P < 0.05). Nerve centroid displaced ulnarly with radial deviation, radial flexion, and radial extension and displaced radially with ulnar deviation, ulnar flexion, and ulnar extension (P < 0.05). Nerve centroid displaced in the dorsal direction with flexion and radial flexion, but in the palmar direction with extension (P < 0.05). Nerve-TCL distance increased with flexion related motion and decreased with extension relation motion (P < 0.05).
INTERPRETATION
The current study advances our understanding the effect of wrist motion on the carpal tunnel and its contents, which has implications for pathomorphological and pathokinematic changes associated with wrist disorders.
Topics: Adult; Carpal Bones; Female; Healthy Volunteers; Humans; Ligaments, Articular; Male; Median Nerve; Motion; Radius; Range of Motion, Articular; Ultrasonography; Wrist; Wrist Joint
PubMed: 31733628
DOI: 10.1016/j.clinbiomech.2019.10.024 -
Folia Medica Cracoviensia 2013Carpal tunnel syndrome belongs to the most common causative factors of surgical interventions in the wrist region. Anatomy of carpal tunnel and median nerve is a subject... (Review)
Review
Carpal tunnel syndrome belongs to the most common causative factors of surgical interventions in the wrist region. Anatomy of carpal tunnel and median nerve is a subject of current revision. Authors paid attention to etiology of the syndrome based on review of literature and their own anatomical studies. They remind basic knowledge on the median nerve and indicate that only based on number of dissections a good orthopedic surgeon may acquire experience necessary to perform procedures in a most appropriate way.
Topics: Carpal Bones; Carpal Joints; Carpal Tunnel Syndrome; Humans; Median Nerve
PubMed: 25556510
DOI: No ID Found -
Journal of Biomechanical Engineering Mar 2023The spacing between the median nerve and transverse carpal ligament (TCL) within the carpal tunnel can potentially affect the nerve morphology. This study aimed to...
The spacing between the median nerve and transverse carpal ligament (TCL) within the carpal tunnel can potentially affect the nerve morphology. This study aimed to quantify the spatial relationship between the median nerve and transverse carpal ligament in asymptomatic hands. Twelve subjects were recruited to image the carpal tunnel using robot-assisted ultrasound. The median nerve and TCL were segmented from each image and three-dimensionally reconstructed using kinematic information from the robot. The TCL-median nerve distance, nerve cross-sectional area, circularity, and position were measured along the entirety of the nerve length within the carpal tunnel. Results were averaged at every 5% of nerve length. At the nerve length percentages of 0% (distal), 25%, 50%, 75%, and 100% (proximal), the TCL-median nerve distance (±SD) was 0.7 ± 0.4, 0.7 ± 0.2, 0.5 ± 0.2, 0.5 ± 0.2, and 0.6 ± 0.3 mm, respectively. The corresponding nerve cross-sectional area was 9.4 ± 1.9, 10.6 ± 2.6, 11.2 ± 2.1, 11.2 ± 1.7, and 9.7 ± 1.9 mm2. A one-way analysis of variance showed no significant differences between the respective percentages of nerve length for TCL-median nerve distance (p = 0.219) and cross-sectional area (p = 0.869). Significant (p < 0.0001) but weak correlations were observed between the TCL-median nerve distance with cross-sectional area (r = -0.247) and circularity (r = -0.244). This study shows that the healthy median nerve morphology is consistent along the continuous nerve length within the carpal tunnel, supporting the use of 2D imaging in the evaluation of the healthy nerve.
Topics: Humans; Median Nerve; Carpal Tunnel Syndrome; Ligaments, Articular; Wrist Joint; Hand
PubMed: 36416297
DOI: 10.1115/1.4056290 -
African Health Sciences Mar 2022The brachial plexus is highly variable, which is a well-known anatomical fact. Repeated observations on anatomical variations, however, constitute current trends in... (Review)
Review
INTRODUCTION
The brachial plexus is highly variable, which is a well-known anatomical fact. Repeated observations on anatomical variations, however, constitute current trends in anatomical research.
CASE SERIES
In an anatomical dissection course, three uncommon variations in the brachial plexus were identified in three young adults' cadavers. In one case, the musculocutaneous nerve gave a branch to the median nerve, while the median nerve gave or received musculocutaneous branches in the two remaining corpses.
CONCLUSION
Anatomical variations of the brachial plexus do occur in our setting. The cases we presented are about anatomical variations of branching patterns of the median and musculocutaneous nerves. Knowledge of those variations is essential for surgery and regional anesthesia of the upper limbs.
Topics: Cadaver; Humans; Median Nerve; Musculocutaneous Nerve; Research
PubMed: 36032460
DOI: 10.4314/ahs.v22i1.33 -
Median nerve and carpal arch morphology changes in women with type 2 diabetes: a case-control study.Journal of Ultrasound Sep 2022The aim of this study is to investigate the changes in median nerve and transverse carpal ligament (TCL)-formed carpal arch morphology as possible risk factors for...
BACKGROUND
The aim of this study is to investigate the changes in median nerve and transverse carpal ligament (TCL)-formed carpal arch morphology as possible risk factors for median nerve entrapment in women with type 2 diabetes.
METHODS
The distal carpal tunnel was imaged using ultrasound in 30 female subjects (15 with type 2 diabetes, 15 controls). The morphological parameters of the median nerve and carpal arch were derived from the ultrasound images. One-way analysis of variance (ANOVA) was used for statistical analysis.
RESULTS
Diabetic women had an enlarged median nerve area (p < 0.05), salong with a maller carpal arch size, as indicated by a reduced palmar bowing index of the TCL (p < 0.05), and arch area (p < 0.05) than controls. The distance from the median nerve centroid to the volar boundary of the TCL was reduced in diabetic women (p < 0.05) compared to the controls.
CONCLUSIONS
Women with type 2 diabetes have reduced available space for the median nerve within the carpal arch due to the enlarged nerve and reduced arch size, making the median nerve more susceptible to entrapment within the tunnel. The current study shows that presence of diabetes increases the risk of median nerve entrapment in women and requires early detection of symptoms to avoid carpal tunnel syndrome.
Topics: Carpal Bones; Carpal Tunnel Syndrome; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Humans; Median Nerve
PubMed: 34472043
DOI: 10.1007/s40477-021-00606-7 -
Hand (New York, N.Y.) Jan 2023Our purpose was to describe structural and morphological features of the median nerve and carpal tunnel on magnetic resonance imaging (MRI) studies obtained before,...
BACKGROUND
Our purpose was to describe structural and morphological features of the median nerve and carpal tunnel on magnetic resonance imaging (MRI) studies obtained before, immediately after, 6 weeks after, and 6 years after endoscopic carpal tunnel release (ECTR).
METHODS
In this prospective cohort study, 9 patients with a diagnosis of carpal tunnel syndrome (CTS) underwent ECTR. Standardized MRI studies were obtained before ECTR, immediately after ECTR, and 6 weeks and 6 years after surgery. Structural and morphological features of the median nerve and carpal tunnel were measured and assessed for each study with comparisons made between each time point.
RESULTS
All 9 patients had complete symptom resolution postoperatively. On the immediate postoperative MRI, there was a discrete gap in the transverse carpal ligament in all patients. There was retinacular regrowth noted at 6 weeks in all cases. The median nerve cross-sectional area and the anterior-posterior dimension of the carpal tunnel at the level of the hamate increased immediately after surgery and these changes were maintained at 6 years.
CONCLUSIONS
We defined structural and morphological changes on MRI for the median nerve and carpal tunnel in patients with continued symptom resolution 6 years after ECTR. Changes in median nerve and carpal tunnel morphology that occur immediately after surgery remain unchanged at mid-term follow-up in asymptomatic patients. Established imaging criteria for CTS may not apply to postoperative patients. Magnetic resonance imaging appears to be of limited clinical utility in the workup of persistent or recurrent CTS.
Topics: Humans; Median Nerve; Carpal Tunnel Syndrome; Follow-Up Studies; Prospective Studies; Ligaments
PubMed: 34933606
DOI: 10.1177/15589447211058819 -
Ultrasound in Medicine & Biology Nov 2019Nerve movement is decreased in patients with carpal tunnel syndrome and can be assessed with ultrasound. In addition to morphologic features, this study describes a...
Nerve movement is decreased in patients with carpal tunnel syndrome and can be assessed with ultrasound. In addition to morphologic features, this study describes a novel approach in which nerve movement and the association with short-term patient-reported outcome are assessed. Ultrasound images at the carpal tunnel inlet were acquired during finger and wrist flexion. Linear regression models were used with the Boston Carpal Tunnel Questionnaire as main outcome. Eighty-five patients were included; 93% completed the 3-mo follow-up. Pre-surgical mean nerve area was 14.5 ± 4.2 mm and decreased to 13.3 ± 3.8 mm (p < 0.001). Displacement in dorsal direction with wrist flexion increased from 1.9 ± 1.3 to 2.4 ± 1.3 mm (p < 0.01). A pre-surgical larger nerve area was associated with more functional improvement (β = -0.024, p = 0.02), but baseline mobility was not. Change in excursion with finger flexion was associated with symptomatic improvement, but with a small effect (β = -0.05, p = 0.01). This indicates that there is limited prognostic potential for dynamic transverse ultrasound in carpal tunnel syndrome.
Topics: Adult; Aged; Aged, 80 and over; Carpal Tunnel Syndrome; Female; Humans; Male; Median Nerve; Middle Aged; Prognosis; Prospective Studies; Surveys and Questionnaires; Ultrasonography
PubMed: 31488311
DOI: 10.1016/j.ultrasmedbio.2019.06.422 -
Clinical Neurophysiology : Official... Aug 2023Reconstruct compound median nerve action currents using magnetoneurography to clarify the physiological characteristics of axonal and volume currents and their...
OBJECTIVE
Reconstruct compound median nerve action currents using magnetoneurography to clarify the physiological characteristics of axonal and volume currents and their relationship to potentials.
METHODS
The median nerves of both upper arms of five healthy individuals were investigated. The propagating magnetic field of the action potential was recorded using magnetoneurography, reconstructed into a current, and analyzed. The currents were compared with the potentials recorded from multipolar surface electrodes.
RESULTS
Reconstructed currents could be clearly visualized. Axonal currents flowed forward or backward in the axon, arcing away from the depolarization zone, turning about the subcutaneous volume conductor, and returning to the depolarization zone. The zero-crossing latency of the axonal current was approximately the same as the peak of its volume current and the negative peak of the surface electrode potential. Volume current waveforms were proportional to the derivative of axonal ones.
CONCLUSIONS
Magnetoneurography allows the visualization and quantitative evaluation of action currents. The currents in axons and in volume conductors could be clearly discriminated with good quality. Their properties were consistent with previous neurophysiological findings.
SIGNIFICANCE
Magnetoneurography could be a novel tool for elucidating nerve physiology and pathophysiology.
Topics: Humans; Action Potentials; Median Nerve; Axons; Evoked Potentials; Magnetic Fields; Electric Stimulation
PubMed: 37307628
DOI: 10.1016/j.clinph.2023.05.006 -
PloS One 2019Essential tremor (ET) is a common movement disorder characterized by postural or kinetic tremor. We aimed to evaluate median nerve enlargement in patients with ET using...
Essential tremor (ET) is a common movement disorder characterized by postural or kinetic tremor. We aimed to evaluate median nerve enlargement in patients with ET using ultrasonography (USG). Thirty-eight hands from 19 patients with ET and 24 hands from 13 controls underwent nerve conduction studies (NCS) and USG at the wrist. Tremor severity was measured using the Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS). The median nerve cross sectional area (mCSA) in USG and NCS parameters were compared using ANCOVA. We evaluated the correlation between mCSA and NCS parameters or FTM-TRS scores using linear regression analysis. mCSA was significantly larger (p<0.001) and NCS parameters were different in two groups. Also, mCSA was negatively correlated with part B and C scores of FTM-TRS (p<0.001 and p = 0.039, respectively). In conclusion, median nerve enlargement with the changes of NCS parameters was observed and correlated with the severity of tremor in patients with ET.
Topics: Action Potentials; Adult; Aged; Essential Tremor; Female; Hand; Humans; Male; Median Nerve; Middle Aged; Muscle, Skeletal; Organ Size; Prospective Studies; Severity of Illness Index; Ultrasonography
PubMed: 31013299
DOI: 10.1371/journal.pone.0215750