Median Nerve Cross-sectional Area Research Articles

Influence of Smartphone Overuse on Grip Strength, Pinch Strength, and Cross-Sectional Area of Flexor Pollicis Longus Tendon and Median Nerve

AbstractBackground and Aim The adverse effects of smartphone size and weight on the hand and hand function have not been studied extensively. This study aimed to investigate the changes to the flexor pollicis longus tendon and median nerve using diagnostic ultrasound for high and low addiction smartphone users.Methodology In this cross-sectional study, 54 healthy male university students were divided into two groups according to the Smartphone Addiction Scale: high and low users. Demographic data, hand grip strength (kg), pinch strength (kg), and smartphone weight, length and width were measured and recorded. Diagnostic ultrasound examination determined the cross-sectional area of the median nerve (mm2) and flexor pollicis longus tendon (mm2) of the dominant and non-dominant hand.Result The cross-sectional area of the median nerve was significantly higher in the high-user group (7.4±1.3 mm2) than the low-user group (6.7±1.0 mm2). The correlation of phone weight, length and width with median nerve area was respectively positive, higher and significant (0.718, 0.747, and 0.733; p<0.05). The flexor pollicis longus tendon in the mid-thenar region was moderately positively correlated with phone length (0.430; p<0.02) for high addiction smartphone users.Conclusion The findings of the current study demonstrates that change to the median nerve and flexor pollicis longus tendon, could be linked to the width, weight and length of the smartphone and high addiction.

A model incorporating ultrasound to predict the probability of fast disease progression in amyotrophic lateral sclerosis

ObjectiveWe aimed to develop a model to predict amyotrophic lateral sclerosis (ALS) disease progression based on clinical and neuromuscular ultrasound (NMUS) parameters. MethodsALS patients were prospectively recruited. Muscle fasciculation (≥2 over 30-seconds, examined in biceps brachii-brachialis (BB), brachioradialis, tibialis anterior and vastus medialis) and nerve cross-sectional area (CSA) (median, ulnar, tibial, fibular nerve) were evaluated through NMUS. Ultrasound parameters were correlated with clinical data, including revised ALS Functional Rating Scale (ALSFRS-R) progression at one year. A predictive model was constructed to differentiate fast progressors (ALSFRS-R decline ≥ 1/month) from non-fast progressors. Results40 ALS patients were recruited. Three parameters emerged as strong predictors of fast progressors: (i) ALSFRS-R slope at time of NMUS (p = 0.041), (ii) BB fasciculation count (p = 0.027) and (iii) proximal to distal median nerve CSA ratio < 1.22 (p = 0.026). A predictive model (scores 0–5) was built with excellent discrimination (area under curve: 0.915). Using a score of ≥ 3, the model demonstrated good sensitivity (81.3%) and specificity (91.0%) in differentiating fast from non-fast progressors. ConclusionThe current model is simple and can predict the probability of fast disease progression. SignificanceThis model has potential as a surrogate biomarker of ALS disease progression.

Effect of Perineural Injection with Different Dextrose Volumes on Median Nerve Size, Elasticity and Mobility in Hands with Carpal Tunnel Syndrome.

This study aimed to investigate the effect of different injectate volumes on ultrasonographic parameters and the correlation to clinical outcomes under perineural dextrose injection (PDI). In this post hoc analysis of the randomized, double-blinded, three-arm trial, ultrasound-guided PDI with either 1 mL, 2 mL, and 4 mL 5% dextrose water was administered, respectively, in 14, 14, and 17 patients. Ultrasound outcomes included mobility, shear-wave elastography (SWE), and cross-sectional area (CSA) of the median nerve; clinical outcomes were Visual Analog Scale (VAS) and Boston Carpal Tunnel Questionnaire (BCTQ) score. Outcomes were measured before injection, and after injection at the 1st, 4th, 12th, and 24th week. For ultrasound outcomes, CSA decreased significantly from baseline data at all follow-up time-points in the 2 mL group (p = 0.005) and the 4 mL group (p = 0.015). The mean change of mobility from baseline showed a greater improvement on the 4 mL group than the other groups at the 1st week post-injection. For clinical outcomes, negative correlation between the VAS and mobility at the 1st (p = 0.046) and 4th week (p = 0.031) post-injection in the 4 mL group were observed. In conclusion, PDI with higher volume yielded better nerve mobility and decreased CSA of median nerve, but no changes of nerve elasticity.

Ultrasound evaluation of the hands and wrists in patients with systemic sclerosis: Osteophytosis is a major contributor to tender joints

ObjectiveTo evaluate the prevalence and clinical associations of ultrasound (US) findings of inflammatory arthritis and joint and soft tissue pathology in patients with systemic sclerosis (SSc). MethodsThe hands and wrists of 43 SSc patients and 35 age-balanced controls were evaluated by clinical exam and musculoskeletal US. Synovial and tenosynovial pathology were assessed using semi-quantitative Gray Scale (GS) and Power Doppler (PD) scoring. US evaluation for osteophytes, erosions, ulnar artery occlusion, and median nerve cross-sectional areas was performed. Tender joints (TJ), swollen joints (SJ), modified Rodnan skin score (mRSS), digital ulcers, contractures, and calcinosis were evaluated. Concordance between US and physical exam findings at each joint region were assessed, and associations between their severity were analyzed. ResultsTJs and SJs were present in 44.2% and 62.8% of SSc patients, respectively. Inflammatory arthritis, defined as having both GS>0 and PD>0, was observed in 18.6% of SSc patients and no controls. There was a high concordance by joint region between GS synovial hypertrophy and osteophytes (κ=0.88) as well as TJs (κ=0.72). SSc patients had more osteophytes compared to controls (48.8% vs 22.9%, p = 0.018) as well as higher osteophyte severity (p = 0.033). ConclusionsDespite a high percentage of tender and swollen joints, less than 20% of SSc patients met criteria for inflammatory arthritis on US. The high concordance of osteophytes with GS synovial hypertrophy and tender joints suggest that osteophytosis may be a significant contributor to joint pain in SSc patients.

The role of diagnostic ultrasound in the examination of carpal tunnel syndrome: an update and systematic review

BackgroundDiagnostic ultrasound is becoming more available and has potential for identifying carpal tunnel syndrome (CTS), but there is a lack of consensus on optimal measurement parameters and interpretation. PurposeThe purpose of this systematic review was to analyze and summarize recent published data evaluating measurement properties of diagnostic ultrasound for use in individuals with CTS. MethodsFive databases were searched to identify studies reporting on diagnostic measurement in individuals ≥18 years of age. Thirty-four studies underwent critical appraisal using Center for Evidence Based Medicine guidelines for diagnostic study accuracy. Each team member independently reviewed and scored the studies and consensus was reached through discussion. ResultsSeventeen studies evaluating 21 unique nerve or tunnel measurements and 9 measurement ratios were included. Measurements of median nerve cross sectional area (CSA) taken at the carpal tunnel inlet consistently demonstrated good to excellent interrater reliability (ICC=0.83-0.93) and good intrarater reliability (r>0.81). All studies supported inlet CSA in differentiating between individuals with and without CTS. Carpal tunnel inlet CSA measurements demonstrated a moderate correlation to the Padua severity classification (r = 0.71), but this varied between studies. Diagnostic accuracy of CSA measured at the carpal tunnel inlet using diagnostic cutoff values ranging from 8.5 mm2 to 12.6 mm2 resulted in a range sensitivity (63%-96.9%) and specificity (67.9%-100%). ConclusionThe US measurement most supported was the median nerve CSA measured at the carpal tunnel inlet. There was no evidence supporting the routine use of diagnostic US for individuals with suspected CTS, and no additional evidence to support replacement of electrodiagnostic studies by US. More research is needed to determine use of US for classifying CTS severity or as a differential diagnostic tool for conditions that mimic CTS. Level of EvidenceN/A

Diagnostic value of high-frequency ultrasound in carpal tunnel syndrome during pregnancy: A case-control study

Background: Carpal tunnel syndrome (CTS) is the most prevalent entrapment syndrome in the upper limbs, for which pregnancy is a known risk factor. CTS diagnosis is confirmed via nerve conduction studies (NCSs), which sometimes is expensive, and the electrical stimulation makes it an unpleasant diagnostic modality, especially for pregnant subjects. Recently, high-frequency ultrasonography (HF-USG) is known as a diagnostic method. This study is concerned with determining the diagnostic value of this modality for CTS among pregnant women. Methods: This cross-sectional case-control study was conducted with 40 CTS cases and 40 matched controls. The HF-USG of wrists was performed bilaterally on all participants with a focus on the median nerve cross-sectional area (MNCSA) at the carpal tunnel (CT) inlet. Results: Mean MNCSA was statistically different between the CTS group (11.71 ± 1.86 mm2, range: 8 to 18 mm2) and the control group (6.75 ± 1.38 mm2, range: 4 to 11 mm2) (P < 0.001). The receiver operating characteristic (ROC) curve was drawn, and the cross-sectional area (CSA) cut-off point of 8.5 mm2 showed sensitivity and specificity of 98% and 93%, respectively. The positive predictive value (PPV) and the negative predictive value (NPV) were 95% and 98%, respectively, with the mentioned point as the diagnostic threshold. Conclusion: HF-USG of the median nerve can be utilized as a preferable alternative to NCS (the current gold standard diagnostic method) in pregnant women, due to its convenience and lower cost, or at least, it can be used as a screening tool among pregnant women with suspicious symptoms.

Impact of the metabolic syndrome on peripheral nerve structure and function in type 2 diabetes.

There is a strong association between the metabolic syndrome in diabetes and the development of peripheral neuropathy; however, the pathophysiological mechanisms remain unknown. Participants with type 2 diabetes and metabolic syndrome (T2DM/MetS, n=89) and type 2 diabetes alone (T2DM; n=59) underwent median nerve ultrasound and excitability studies to assess peripheral nerve structure and function. A subset of T2DM/MetS (n=24) and T2DM (n=22) participants underwent confocal microscopy to assess central and inferior whorl corneal nerve structure. Neuropathy severity was assessed using the modified Toronto Clinical Neuropathy Score (mTCNS). Diabetes groups were similar for age, sex distribution, diabetes duration, hemoglobin A1c , insulin treatment, and renal function. Sixty healthy controls similar for age and sex distribution were recruited for comparison. Participants with T2DM/MetS manifested with a greater mTCNS compared to T2DM (p<0.05). Median nerve cross-sectional area was larger in the T2DM/MetS group compared to the T2DM cohort (p<0.05). Participants with T2DM/MetS had reductions in central (all p<0.01) and inferior whorl (all p<0.05) nerve measures. Compared to T2DM, the T2DM/MetS group demonstrated more severe changes in nerve excitability measures, which was due to reduced sodium channel permeability and sodium-potassium pump function. In comparison, only sodium channel permeability was reduced in the T2DM group. Compared to participants with type 2 diabetes alone, those with diabetes and metabolic syndrome manifested greater alterations in peripheral nerve structure and function, which may be due to reduced function of the sodium-potassium pump.

Median nerve swelling is an independent risk factor of carpal tunnel syndrome in chronic hemodialysis patients

Carpal tunnel syndrome (CTS) has a wide variety of underlying causes and occurs in association with dialysis. Early diagnosis is essential to prevent permanent nerve damage and functional sequelae. We evaluated the association between CTS and cross-sectional area (CSA) of the median nerve in chronic hemodialysis (HD) patients. Patients with end-stage renal disease (ESRD) on maintenance HD via arteriovenous fistula were enrolled. We divided forty-three patients into two groups; patients diagnosed with CTS (n=19) and patients without CTS (n=24). The median nerve CSA was measured at the wrist (CSA-W) and forearm (CSA-F) by ultrasonography. Median nerve swelling was assessed by the wrist-to-forearm ratio (WFR). There were no significant differences in the underlying causes of CKD and adequacy of dialysis between the two groups (P = NS). The patients with CTS showed significantly higher WFR than the patients without CTS (P = 0.001). Univariate Cox regression analysis revealed that WFR > 1.25 (odds ratio, 6.30; 95% confidence interval, 1.44 to 27.45; P = 0.014) was associated with CTS in HD patients. The factors traditionally associated with CTS such as age, sex, diabetes, vintage of HD, β2-MG, intact PTH and Kt/V were not associated with CTS. After adjustment for age and sex, we found a strong correlation between CTS and the WFR > 1.25 (odds ratio, 10.8; 95% confidence interval, 1.85 to 62.4; P = 0.008). High WFR was associated with the development of CTS, and median nerve swelling was an independent risk factor of CTS in chronic HD patients. (Pusan National University Yangsan Hospital Review Board IRB No. 05-2015-137). This article is protected by copyright. All rights reserved.

T2 mapping of the median nerve in patients with carpal tunnel syndrome and healthy volunteers.

We investigated the changes in MRI T2 mapping values in subjects with carpal tunnel syndrome (CTS) compared to healthy controls. We enrolled 71 patients with CTS and 26 healthy controls. Median nerve T2 values were measured at the distal carpal tunnel, hamate bone, proximal carpal tunnel, and forearm levels. These were compared between patients and controls and correlated with median nerve cross-sectional area (CSA) and nerve conduction measurements. The mean T2 values at the proximal carpal tunnel levels were higher in the CTS group (56.7 ms) than in the control group (51.2 ms, P = .02) and also were higher than at the distal carpal tunnel (51.0 ms, P < .001) and forearm levels (47.6 ms, P < .001). T2 values were not significantly associated with CSA or nerve conduction measurements. T2 mapping of the carpal tunnel provides qualitative information on median nerve pathology but does not reflect CTS severity.

Ultrasonographic Measurement of the Median Nerve Transverse Diameter at the Wrist for Diagnosing Carpal Tunnel Syndrome.

Background: Ultrasonographically measuring the median nerve cross-sectional area (MN-CSA) is a useful and complementary method for diagnosing carpal tunnel syndrome (CTS). This study investigated the usefulness of the median nerve transverse diameter (MN-TD) as a simpler and easier technique than MN-CSA for diagnosing CTS severity. Methods: We examined 145 hands from 101 patients with CTS and 114 age- and gender-matched control hands. Based on the electrodiagnostic findings, the severity of CTS was divided into minimal, mild, moderate, severe and extreme. An ultrasonographic assessment of MN-TD and MN-CSA was performed to measure the maximal values around the carpal tunnel inlet level. The values were assessed for comparisons between the CTS and control groups and for the evaluation of differences by CTS severity. Results: The ultrasonographic measurements of MN-TD and MN-CSA were significantly increased in the CTS group compared to the normal group. Furthermore, both measurements significantly increased with increasing CTS severity. A receiver operating characteristic curve (ROC) analysis showed that participants with MN-TD > 7.2 mm had CTS with 88% specificity and 74% sensitivity, and those with MN-CSA > 12.0 mm2 had CTS with 86% specificity and 84% sensitivity. Conclusions: Ultrasonographic measurement for MN-TD may be useful for diagnosing CTS patients and predicting the severity.

Clinical, electrophysiological, and ultrasound evaluation for early detection of musculoskeletal hand disorders and nerve entrapment in mobile phone users

IntroductionSmartphone overuse may lead to musculoskeletal manifestations, such as carpal tunnel syndrome (CTS) and arthritis of hand joints, with an increased median nerve cross-sectional area (CSA). ObjectiveThe aim of this study is the early detection of musculoskeletal hand disorders using ultrasound techniques, and to detect nerve entrapment using clinical evaluation, ultrasound, and electrophysiological studies, in university employees younger than 35 years using mobile phones. Function is assessed using the Michigan Hand Outcomes Questionnaire (MHQ). Materials and methodsCross-sectional controlled study included 74 smartphone users classified into two groups according to a smartphone addiction scale (SAS), into high and low smart phone users, with 35 non-smartphone users with matched age and gender as a control group. A clinical assessment of nerve entrapment symptoms was performed, and the Michigan Hand Outcomes Questionnaire (MHQ), with a total score from 0 to100, was used to assess hand function. Electrodiagnostic studies of median and ulnar nerves were used to detect early nerve entrapment. Bilateral ultrasound was performed in order to assess the median nerve CSA and involvement of thumb and small hand joints. The data collected were analysed using the SPSS program version 20. ResultsCSAs of median nerves were significantly higher in the dominant hand of high smartphone users than in low and non-smartphone users (p<0.001). There was a significant positive correlation between CSA and SAS (r=0.45), visual analogue scale (VAS) (r=0.61), and duration of smartphone use (r=0.80), with negative correlation with MHQ (r=−0.63). Significant differences in were found in the electrophysiological studies of median and ulnar nerves. The mean ultrasound score for both hands was higher in the high smartphone users compared to low smartphone users (15.08±4.17 vs. 6.46±1.38, p<.001). ConclusionsThere is increased median nerve CSAs among high smartphone users associated with prolongation of both sensory and motor latencies and slow conduction velocities. Caution should be exercised when using mobile phones, in order to minimise the risk of developing hand musculoskeletal disorders.

Ultrasonographic Measurement of Mean Cross-sectional Area of the Median Nerve in Pregnant Women in a Tertiary Level Hospital of Nepal: A Descriptive Cross-sectional Study.

Pregnancy is one of the predisposing factors for carpal tunnel syndrome, which may manifest as swelling of the median nerve. The purpose of this study was to obtain the mean cross-sectional area of median nerve using ultrasound in pregnant females at carpal tunnel inlet and its variations with different trimesters. A total of 102 pregnant females at first, second and third trimesters were evaluated for median nerve with ultrasonography. Mean cross sectional area of median nerve was calculated in both hands by using two methods- direct and indirect. The study was conducted after obtaining ethical clearance from Institutional Review Board of Institute of Medicine, and after obtaining the written informed consent from the subjects. Convenience sampling technique was used. Data obtained were compiled and analyzed using Statistical Package for the Social Sciences version 20. The overall mean cross-sectional area was 6.84±1.09 mm2 using direct method and 7.09±1.19 mm2 using indirect method. The values obtained with indirect method were greater than that obtained with direct method. Mean cross-sectional area of the median nerve were higher at third trimester in both hands and by both direct and indirect methods. From the study conducted, the normal value of mean cross-sectional area of median nerve in pregnant females was established.

Ultrasound of the Median Nerve in the Surgical Treatment of Severe Carpal Tunnel Syndrome.

High-resolution ultrasound (HRU) has demonstrated utility in the diagnosis and treatment of carpal tunnel syndrome (CTS) by measuring the cross-sectional area (CSA) of the median nerve. We investigated whether HRU could be helpful in evaluating outcomes of carpal tunnel release in patients with severe CTS. Patients greater than 18 years of age with severe CTS on electrodiagnostic (EDX) studies and scheduled to have carpal tunnel release were enrolled. At baseline visit within 6 weeks preoperatively, HRU was used to measure median nerve CSA at the carpal tunnel inlet and forearm, and the wrist/forearm ratio (WFR) was calculated. Patients also completed the Boston Carpal Tunnel Questionnaire (BCTQ). Ultrasound and BCTQ were repeated at 6 weeks and 6 months postoperatively. Twelve patients completed the study (average age, 69 years; range, 52-80 years). The WFR improved significantly at 6 weeks and reached normal levels at 6 months. The CSA at the wrist also improved at 6 months, although this did not reach statistical significance (P = .059). Boston Carpal Tunnel Questionnaire symptoms and function scores improved significantly at 6 weeks and 6 months. High-resolution ultrasound provides an objective assessment of surgical outcomes in cases of severe CTS, demonstrating normalization of WFR in our series of successful cases. Future study of poor outcomes may help determine whether improvement in WFR and CSA can provide reassurance and support for observation rather than reoperation. Ultrasound also provides anatomical evaluation and may be helpful in cases with medicolegal or psychosocial issues while potentially being less costly and better tolerated than EDX or magnetic resonance imaging.

Palmar Musculature: Does It Affect the Development of Carpal Tunnel Syndrome? A Pilot Study.

Background The etiology of carpal tunnel syndrome (CTS) is multifactorial. Static mechanical characteristics of CTS have been described, but dynamic (muscular) parameters remain obscure. We believe that musculature overlying the transverse carpal ligament may have an effect on carpal tunnel pressure and may explain the prevalence of CTS in manual workers. Questions/Purposes To utilize magnetic resonance imaging (MRI) imaging to estimate the amount of muscle crossing the area of the carpal tunnel and to compare these MRI measurements in patients with and without documented CTS. Methods A case-control study of wrist MRI scans between January 1, 2018, and December 1, 2019, was performed. Patients with a diagnosis of CTS were matched by age and gender with controls without a diagnosis of CTS. Axial MRI cuts at the level of the hook of the hamate were used to measure the thenar and hypothenar muscle depth overlying the carpal tunnel. Muscle depth was quantified in millimeters at three points: midcapitate, capitate-hamate border, capitate-trapezoid border. Average depth was calculated by dividing the cross-sectional area (CSA) by the transverse carpal ligament width. Statistical analysis included Student's t -test, chi-square test, and Pearson's correlation coefficient calculation. Results A total of 21 cases and 21 controls met the inclusion criteria for the study. There were no significant differences in demographics between case and control groups. The location and depth of the musculature crossing the carpal tunnel were highly variable in all areas evaluated. A significantly positive correlation was found between proximal median nerve CSA and muscle depth in the capitate-hamate area (correlation coefficient = 0.375; p = 0.014). CSA was not significantly associated with chart documented CTS. Conclusions We found large variability in our measurements. This likely reflects true anatomical variation. The significance of our findings depends on the location of the muscles and the line of pull and their effect on the mechanics of the transverse carpal ligament. Future research will focus on refining measurement methodology and understanding the mechanical effect of the muscular structure and insertions on carpal tunnel pressure. Level of Evidence This is a Level 3, case-control study.

Evaluation of the relationship between coronary slow flow phenomenon and serum magnesium levels

Aim: Splint use is often recommended following wrist injection patients diagnosed with carpal tunnel syndrome (CTS), but there is not any data in the literature pertaining to the impact of splint treatment, used before injection, on the results of local injection treatment. The aim of this study to evaluate whether or not splint use starting before the injection would impact the local injection treatment outcomes.Materials and methods: Fifty seven patients (57 hands) with CTS and underwent ultrasound-guided injection were included in the study, and patients were divided into two groups in terms of splint use. Median nerve cross-sectional area (MNCSA), pain/numbness by visual analogue scale (VAS), symptoms and functionality by Boston Carpal Tunnel Questionnaire (BCTQ) were investigated before injection and 15 days after injection.Results: There was significant change over time in MNCSA, VAS, and BTCQ scores in groups. The patients not using splint group had significantly higher percentage change in VAS nighttime score.Conclusion: Our findings has shown that using neutral wrist splint, starting before and continuing after injection treatment, did not increase the injection treatment efficacy and may actually have negative effect on improvement in VAS nighttime scores.

The effect of splint use on outcomes in ultrasound guided injection of carpal tunnel syndrome

Aim: Splint use is often recommended following wrist injection patients diagnosed with carpal tunnel syndrome (CTS), but there is not any data in the literature pertaining to the impact of splint treatment, used before injection, on the results of local injection treatment. The aim of this study to evaluate whether or not splint use starting before the injection would impact the local injection treatment outcomes.Materials and methods: Fifty seven patients (57 hands) with CTS and underwent ultrasound-guided injection were included in the study, and patients were divided into two groups in terms of splint use. Median nerve cross-sectional area (MNCSA), pain/numbness by visual analogue scale (VAS), symptoms and functionality by Boston Carpal Tunnel Questionnaire (BCTQ) were investigated before injection and 15 days after injection.Results: There was significant change over time in MNCSA, VAS, and BTCQ scores in groups. The patients not using splint group had significantly higher percentage change in VAS nighttime score.Conclusion: Our findings has shown that using neutral wrist splint, starting before and continuing after injection treatment, did not increase the injection treatment efficacy and may actually have negative effect on improvement in VAS nighttime scores.

Application of shear wave elastography and median nerve cross-section area in the diagnosis and staging of carpal tunnel syndrome: a case-control study

PurposeImaging is gaining a more prominent role in the diagnosis of carpal tunnel syndrome (CTS), especially ultrasonography. Shear wave elastography (SWE) is a novel qualitative method to study mechanical changes in tissue. In this study, we aim to assess the role of SWE in diagnosing and staining of the disease.Material and methodsA total of 124 wrists were included in the study. Seventy wrists had CTS, and 54 were included as the control group. All of the wrists with CTS had staging done with nerve conduction study. All patients underwent ultrasonography by an expert radiologist and had the SWE and cross-section of the median nerve determined. These values were compared among the 2 groups and different stages of CTS. The receiver operating characteristic curve was utilized to assess the diagnostic role of each of the variables.ResultsCross-section area (CSA) and SWE were significantly different between the 2 groups (p = 0.0001). CSA was also significantly different among various stages of CTS. SWE was not significantly different among moderate and severe stages of CTS. Both of the variables had a good ability to distinguish mild CTS from healthy wrists (p = 0.0001).ConclusionSWE can be used in diagnosing CTS and in the staging of the disease.

Reduction in median nerve cross-sectional area at the forearm correlates with axon loss in carpal tunnel syndrome

ObjectiveTo explore the relationship between axon loss and measured cross-sectional areas of the median nerve (MN) in severe carpal tunnel syndrome (CTS). MethodsIn this retrospective study of 158 examined wrists, we compared axon loss to the ultrasound parameters MN cross-sectional area at the wrist (wCSA), MN cross-sectional area at the forearm (fCSA) and wrist-to-forearm ratio (WFR), in patients with moderate to extreme CTS. Axon loss was evaluated by needle electromyography (EMG) of the abductor pollicis brevis muscle (spontaneous activity and reduction of interference pattern). ResultsBoth the spontaneous activity and interference pattern reduction correlated negatively to fCSA (r = −0.189, p = 0.035; r = −0.210, p = 0.019; respectively). In moderate CTS, both the spontaneous activity and interference pattern reduction correlated positively to WFR (r = 0.231, p = 0.048; r = 0.232, p = 0.047; respectively). The WFR was highest when slight spontaneous activity was detected. Neither wCSA nor WFR correlated with axon loss in severe and extreme CTS. ConclusionsThe fCSA is smaller when axon loss in CTS is more prominent. The WFR is highest when CTS is associated with slight axon loss of the MN. SignificanceCTS might cause retrograde axonal atrophy detected as small fCSA. Prominent axon loss in CTS may reduce the diagnostic value of WFR.

Ultrasonography Findings of the Carpal Tunnel after Endoscopic Carpal Tunnel Release for Carpal Tunnel Syndrome.

ObjectiveTo investigate changes in the median nerve, retinaculum, and carpal tunnel on ultrasound after successful endoscopic carpal tunnel release (ECTR).Materials and MethodsThis prospective study involved 37 wrists in 35 patients (5 male, 30 female; mean age ± standard deviation [SD], 56.9 ± 6.7 years) with primary carpal tunnel syndrome (CTS). An in-house developed scoring system (0–3) was used to gauge the clinical improvement after ECTR. Ultrasound was performed before ECTR, and at 1, 3, and 12 months post-ECTR. Changes in the median nerve, flexor retinaculum, and carpal tunnel morphology on ultrasound after ECTR were analyzed. Ultrasound parameters for different clinical improvement groups were compared.ResultsAll patients improved clinically after ECTR. The average clinical improvement score ± SD at 12 months post-ECTR was 2.2 ± 0.7. The median nerve cross-sectional area proximal and distal to the tunnel decreased at all time intervals post-ECTR but remained swollen compared to normal values. Serial changes in the median nerve caliber and retinacular bowing after ECTR were more pronounced at the tunnel outlet than at the tunnel inlet. The flexor retinaculum had reformed in 25 (68%) of 37 wrists after 12 months.ConclusionPostoperative changes in median nerve and retinaculum parameters were most pronounced at the tunnel outlet. Even in patients with clinical improvement after ECTR, nearly all ultrasound parameters remain abnormal at one year post-ECTR. These ultrasound parameters should not necessarily be relied upon to diagnose persistent CTS after ECTR.

A study of median nerve cross sectional area in patients with mild to moderate idiopathic carpal tunnel syndrome

Introduction: Carpal tunnel syndrome is the most common entrapment neuropathy and is caused by median nerve compression at the wrist as it passes through carpal tunnel. Aim: To detect cross sectional area (CSA) of median nerve at the level of distal palmar crease and ratio of cross sectional area at level of proximal carpal tunnel to area 5 cm proximal to carpal tunnel using ultrasound. Materials and Methods: Consecutive patients of age between 18 and 70 years, who presented with paraesthesia of hands (aggravated by holding or keeping hand elevated or with history of nocturnal worsening) and electrophysiological confirmed as mild to moderate idiopathic cases of carpal tunnel syndrome were included in the study. Baseline nerve conduction study was done as per standard protocol for carpal tunnel syndrome. Nerve ultrasound was done with high frequency linear-array transducer (7-14 Hz). Results: 50 wrists in 30 Patients with CTS were studied. Females were more involved with a male: female ratio of 1:5. Mean age was 56.8 years (range 25–82 years). Majority of the cases were bilateral (67%). Dominant hand was involved more (80%) than non-dominant one. Most common symptoms were numbness (100%) and paraesthesia on holding (90.91%). On nerve ultrasound, all patients had CSA of median nerve at proximal carpal tunnel more than 10 square millimetre .The wrist fore-arm CSA ratio was more than 1 in all cases. Majority of the hands were having a cross sectional area 10-11.9 square millimetre and more than 16 square millimetre. We found correlation between CSA at distal palmar crease and median sensory conduction studies. Conclusion: Our study affirms previous studies in demonstrating the usefulness of ultrasonography in diagnosing CTS. Median nerve Cross-sectional area can be used for clinical screening of Carpal tunnel syndrome patients. Keyword: Carpal tunnel syndrome, Cross sectional area, Wrist-ultrasound.