Comparison of sonography and electrodiagnostic testing in the diagnosis of carpal tunnel syndrome

Ultrasound Use by Upper Extremity Surgeons in 2020: A Survey of ASSH Members

BACKGROUND

The use of musculoskeletal ultrasound (US) among hand surgeons appears to be increasing. The purpose of this study was to determine the utilization patterns and attitudes regarding US among American Society for Surgery of the Hand (ASSH) members in 2020 as well as the changes in usage patterns since a previous survey in 2015.

METHODS

In 2020, an updated and expanded 27-question survey was distributed to 4852 members of the ASSH. Questions assessed respondent demographics, training, and practice patterns, and access, utilization, training, and opinions pertaining to US.

RESULTS

A total of 418 surveys (8.6%) were analyzed. Compared to 2015, there was an increase in the percentage of respondents using US for diagnostic purposes (51%-68%), as well as having personal access to US machines (43% to 58%). US use to assist in diagnosing carpal tunnel syndrome increased from 19% to 27%. The most common reason for using US was convenience and practice efficiency, while the most common reasons for not using US was no machine access. In 2020, 33% of respondents performed US-guided injections.

CONCLUSIONS

Compared to 2015, the majority of responding upper extremity surgeons now have personal access to US machines. Utilization of diagnostic US appears to be increasing, and two-thirds of respondents believed that US use will continue to increase among upper extremity surgeons.

Patients Prefer Ultrasound to Nerve Conduction Studies for the Diagnosis of Carpal Tunnel Syndrome

Background

The net promoter score (NPS) allows analysis of patient satisfaction and preference between treatment and/or diagnostic testing. Electrodiagnostic testing (EDX) and ultrasound (US) are commonly used diagnostic tests for carpal tunnel syndrome. Although EDX is reliable for diagnosing carpal tunnel syndrome (CTS), it can be uncomfortable and inconvenient for patients. We aimed to determine whether patients preferred US or EDX studies for the diagnosis of CTS, using the NPS.

Methods

Seventy-five patients presenting to the clinic for evaluation of CTS complaints who had EDX were prospectively studied. US evaluation of the median nerve was then completed at time of evaluation. Patient satisfaction was determined by asking, "how likely are you to recommend this procedure to a friend or relative?" for both EDX and US. Patient demographics, comorbidities, CTS-6 questionnaire (CTS-6), and functionality assessed through patient-reported qDASH were also recorded.

Results

Sixty-five patients were included in the study. Most patients did not have any comorbidities and were nonsmokers. The gender composition was similar, and the average age of the enrolled patients was 58. The NPS for US was significantly higher than EDX (P < 0.0001). Patients with diabetes mellitus rated their EDX experience significantly lower than those without diabetes mellitus.

Conclusions

Patients are more likely to recommend US instead of EDX in the evaluation of CTS complaints. This allows for shared decision-making between the patient and provider if ordering diagnostic testing for CTS.

Sonographic reference values for median nerve cross-sectional area: A meta-analysis of data from healthy individuals

Objective

Establish median nerve CSA reference values and identify patient-level factors impacting diagnostic thresholds.

Methods

Studies were identified through a robust search of multiple databases, and quality assessment was conducted using a modified version of the National Institute of Health Study Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. A meta-analysis was performed to identify normative values stratified by anatomic location. A meta-regression was conducted to examine heterogeneity effects of age, sex, and laterality.

Results

The meta-analysis included 73 studies; 41 (56.2%) were high quality. The median nerve CSA [95% CI] was 6.46mm2 [6.09-6.84], 8.68mm2 [8.22-9.13], and 8.60mm2 [8.23-8.97] at the proximal forearm, the carpal tunnel inlet, and the proximal carpal tunnel, respectively. Age was positively associated with CSA at the level of proximal carpal tunnel (β=0.03mm2, p=0.047). Men (9.42mm2, [8.06-10.78]) had statistically larger proximal tunnel CSA (p = 0.03) as compared to women (7.71mm2, [7.01-8.42]). No difference was noted in laterality.

Conclusion

A reference value for median nerve CSA in the carpal tunnel is 8.60mm2. Adjustments may be required in pediatrics or older adults. The diagnostic threshold of 10.0mm2 for male patients should be cautiously applied as the upper limit of normative averages surpasses this threshold.

Comparison of Diagnostic Accuracy of Electrodiagnostic Testing and Ultrasonography for Carpal Tunnel Syndrome

BACKGROUND

Confirmatory methods such as electrodiagnostic testing (EDX) and ultrasonography (US) are currently used to support a clinical diagnosis of carpal tunnel syndrome (CTS). Scientific consensus long has preferred nerve conduction studies (NCS); however, recent studies have advocated for a diagnostic niche for ultrasound examination. This study seeks to compare diagnostic accuracies, sensitivity, and specificity between these 2 diagnostic tools.

METHODS

An institutional database was retrospectively analyzed to reveal 402 upper extremity cases (265 patients) with potential for CTS diagnosis. Demographics, NCS results, and US findings were determined for each patient case. Sensitivity and specificity values were determined for each diagnostic modality using Carpal Tunnel Syndrome 6 (CTS-6), a validated clinical CTS scoring system, as the reference standard. Demographic and diagnostic values were compared between positive and negative CTS groups using the 2-tailed t test and χ2 test.

RESULTS

Electrodiagnostic testing resulted in a sensitivity of 87% and a specificity of 27%, whereas US produced a sensitivity of 76% and a specificity of 51%. No statistical difference was found in CTS-6 scores between NCS-positive and NCS-negative patient hands, whereas CTS-6 scores were significantly greater in US-positive CTS cases than US-negative cases (15.2 and 13.1, respectively, P < .001).

CONCLUSIONS

Electrodiagnostic testing yields a greater sensitivity for CTS than US examination. However, US testing aligns more closely with CTS-6 scores and results in a greater specificity and positive predictive value. These findings suggest that US holds a non-trivial niche in CTS diagnosis and that EDX is not clearly preferable for all CTS diagnoses and cases.

The cross-sectional morphology of median nerve in carpal tunnel of healthy, adult population: A systematic review and meta-analysis

The cross-section area is a crucial parameter to assess peripheral neuropathy. The ultrasonographic evaluation of cross-section area of median nerve is a low-cost and readily available tool for diagnosis and assessment. However, the intra-nerve dimensional variability and its normative reference value in a healthy subject are missing. The current meta-analysis aims to capture the median nerve cross-section area for healthy subjects and generate a comprehensive ultrasonographic reference data set for each population.

METHODS

The full text of manuscripts were collected after short-listing the abstracts collected from search strategy. A quality assurance tool was used to capture the risk of bias of each study after reviewing the included manuscripts. The pooled estimate of cross-section area was stratified according to anatomical landmarks, sex, and ancestry.

RESULTS

A total of 97 observational studies dealt with 6679 wrists of healthy subjects were included. The pooled estimate of the cross-section area of median nerve at carpal tunnel inlet was 8.54mm² [95% CI: 8.34-8.74mm²]. The same pooled estimate at carpal tunnel outlet was 8.03mm² [95% CI: 7.46-8.60mm²]. Both these pooled estimates have significant correlation with mean age of population. Age and sex were two primary predictors of the cross-section of median nerve. The flattening ratio, circularity, and wrist-forearm ratio of median nerve were also computed.

CONCLUSION

These normative data could serve as a reference for assessing median nerve pathologies, including carpal tunnel syndrome. The ethnic variation of pooled estimate and heterogeneity will guide clinician set up the reference value for diagnostic criteria.

Use of Ultrasound in Patients With Carpal Tunnel Syndrome: A Cost-Effective Solution to Reduce Delays in Surgical Care

PURPOSE

Currently, electrodiagnostic testing, which comprises electromyogram (EMG) and nerve conduction studies (NCS), is the most commonly used method for confirming the clinical diagnosis of carpal tunnel syndrome (CTS). Electromyogram and NCS can be costly, can require multiple visits, may induce anxiety, and may be painful for patients. The purpose of this study was to determine whether replacing EMG/NCS with ultrasound (US), performed by the treating surgeon, to diagnose CTS decreases time to surgery and the number of office visits.

METHODS

We retrospectively reviewed a database that consisted of patients who presented to our department with numbness and/or tingling in the hand(s). We assessed the patients' histories for any subsequent carpal tunnel release, dates of diagnosis, dates of surgery, the number of CTS-related medical visits, and diagnostic methods employed. A fellowship-trained hand surgeon performed US examination, and the patients were referred for EMG/NCS testing. We collected data prior to surgery using the Boston Carpal Tunnel Questionnaire to evaluate symptom severity scale and functional status scale scores. We performed linear regression to assess differences in the time to surgery and the number of medical visits prior to carpal tunnel release.

RESULTS

Patients who had the diagnosis confirmed by the surgeon using US (n = 34) underwent surgical intervention 3-4 weeks earlier, with 1.8 fewer medical visits on average than the number of medical visits for those who had their diagnosis confirmed using EMG/NCS (n = 98).

CONCLUSIONS

If a confirmatory method for the diagnosis of CTS is required or desired by the treating surgeon, surgeon-conducted US might have an impact on the efficiency of care for patients with CTS.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Ultrasound Measurement Error and Its Implications for Carpal Tunnel Syndrome Diagnosis

Background: Ultrasound (US) measurement of the cross-sectional area (CSA) of peripheral nerves has been validated as a method for diagnosing peripheral nerve compression; however, the accuracy of US measurements and variation among examiners have not been well established. The purpose of this study was to determine the percent error from a known measurement among multiple US examiners using a gel phantom model. Methods: A US phantom gel, with 2 embedded, premeasured cylindrical objects, was constructed, and 9 residents, fellows, and attending physicians with upper-extremity US experience were recruited to use US to measure the CSA of each object. Percent error was calculated based on the premeasured value of each object, which was measured using digital calipers, and was calculated using the formula for CSA of a cylinder (A = pi × r²) prior to insertion into the gel phantom. Results: The mean percent error for examiners' CSA measurements was 9.0% ± 4.7% (range, 1.6%-17.0%). There was a greater mean percent error for the smaller measured object compared with the larger one. There was a very minimal decline in percent error with increase in years of training experience (slope = -0.029, R² = 0.0002). Conclusion: This study demonstrates that US examiners were able to measure CSAs of premeasured objects with approximately 10% error. When considering the use of US for the diagnosis of carpal tunnel syndrome, a cutoff value of 10 mm² is often used, and therefore in cases where measurements are within 10% of the diagnostic threshold, caution should be exercised in interpreting the results.

A systematic review: normative reference values of the median nerve cross-sectional area using ultrasonography in healthy individuals

Median nerve cross-sectional area (CSA) was used for screening and diagnosis of neuropathy, but few studies have suggested reference range. Hence, this systematic review was performed to evaluate a normative values of median nerve CSA at various landmarks of upper limb based on ultrasonography. PubMed and Web of science were used to search relevant articles from 2000 to 2020. Forty-one eligible articles (2504 nerves) were included to access median nerve CSA at different landmarks (mid-arm, elbow, mid-forearm, carpal tunnel (CT) inlet and CT outlet). Data was also stratified based on age, sex, ethnicity, geographical location, and method of measurement. Random effects model was used to calculate pooled weighted mean (95% confidence interval (CI), [upper bound, lower bound]) at mid-arm, elbow, mid-forearm, CT inlet and outlet which found to be 8.81 mm², CI [8.10, 9.52]; 8.57 mm² [8.00, 9.14]; 7.07 mm² [6.41, 7.73]; 8.74 mm² [8.45, 9.03] and 9.02 mm² [8.08, 9.95] respectively. Median nerve CSA varies with age, geographical location, and sex at all landmarks. A low (I² < 25%) to considerable heterogeneity (I² > 75%) was observed, indicating the variation among the included studies. These findings show that median nerve CSA is varying not only along its course but also in other sub-variables.

Diagnostic Value of Ultrasound for Detecting Carpal Tunnel Syndrome in Patients With Rheumatoid Arthritis: A Three-Arm Cross-Sectional Study

Objective:

This study was conducted to assess the diagnostic value of sonography in detecting carpal tunnel syndrome (CTS) in patients with rheumatoid arthritis (RA) and to compare the results with a normal control group.

Materials and Methods:

In this three-arm cross-sectional study, the sonographically measured median nerve cross-sectional area (MNCSA) was compared in three groups: RA patients with CTS, RA patients without CTS, and normal subjects (no RA, no CTS). A nerve conduction study (NCS) was performed for all enrolled participants, across the three study arms.

Results:

In this study, 38 RA patients (17 in CTS group and 21 in no CTS group) and 19 healthy subjects were recruited. The MNCSAs were 11.86 (±1.87) mm2 in RA patients with CTS, 10.16 (±1.71) mm2 in RA patients without CTS, and 9.42 (±1.46) mm² in healthy control patients. The accuracy of sonography in detecting CTS was 0.79 (95% confidence interval, 0.67–0.91), with a sensitivity and specificity of 88% and 57%, respectively. The MNCSA in CTS group was significantly higher than the control group ( P = .02).

Conclusion:

In this cohort, the sonographic measurement of MNCSA was an accurate and sensitive method for the diagnosis of CTS, especially in its early stages. In addition, in this cohort, RA without CTS did not increase the MNCSA.

Contradições diagnósticas na síndrome do túnel do carpo

Objetivo Diante da divergência sobre a necessidade de exames complementares, como ultrassonografia (US) e eletroneuromiografia (ENMG) para o diagnóstico da síndrome do túnel do carpo (STC), objetivamos elucidar qual deles apresenta maior precisão na confirmação da presença ou não desta afecção.

Métodos Um total de 175 pacientes de um ambulatório de cirurgia da mão foram avaliados clinicamente, e os resultados dos testes clínicos (Tinel, Phalen e Durkan), da US (normal ou alterada) e da ENMG (normal, leve, moderada e grave) foram anotados, cruzados, e submetidos a análise estatística para verificar a concordância entre eles.

Resultados A idade média da amostra era de 53 anos, sendo prevalente o sexo feminino (159 casos). Dos pacientes com teste clínico positivo, 43,7% apresentavam US normal, e 41,7%, ENMG sem alterações. Foram encontrados resultados negativos no Tinel em 46,9% no Phalen em 47,4%, e no Durkan em 39,7%. No cruzamento entre a ENMG e os demais métodos diagnósticos, houve pouca concordância estatística.

Conclusão Não houve concordância entre os resultados dos exames clínicos, da US e da ENMG no diagnóstico da STC, e não há exame clínico ou complementar para STC que determine a conduta terapêutica com precisão.

Nível de Evidência IV, Série de Casos.

Does Patient Sex Affect Ultrasound Cutoff Values for Severity Grading of Carpal Tunnel Syndrome?

PURPOSE

A growing body of evidence supports ultrasound (US) as an alternative first-line confirmatory test for carpal tunnel syndrome (CTS). Recent studies have demonstrated a correlation of US cross-sectional area with electrodiagnostic (EDX)-determined severity; however, it is unclear whether patient sex affects the cutoff values used for determining severity. The purpose of this study was to determine if patient sex affects US graded severity when using EDX as the reference standard.

METHODS

A cohort of 367 women and 46 men, aged 18-90 years, from 1 orthopedic hand surgeon's practice underwent EDX and US. Distal motor latency and distal sensory latency of the median nerve were recorded. Severity was classified using a modified Bland severity scale. The US measurements of the cross-sectional area of the median nerve at the wrist crease were acquired by a fellowship-trained hand surgeon. Separate receiver operator characteristic curve analyses of the male and female groups were performed for US cutoff values.

RESULTS

The cutoff value in both the female (F) and male (M) patients was 11 mm² for mild (area under the curve = 0.76 F; 0.78 M), 12 mm² for moderate (area under the curve = 0.75 F; 0.73 M), and 13 mm² for severe (area under the curve = 0.75 F; 0.71 M) CTS. The sensitivity of the cutoffs for mild, moderate, and severe CTS in the female and male groups was 49% and 56%, 44% and 50%, and 49% and 44%, respectively. The specificity of the cutoffs for mild, moderate, and severe CTS in the female and male groups was 75% and 79%, 74% and 82%, and 83% and 78%, respectively.

CONCLUSIONS

Patient sex does not appear to have a significant impact on the determination of CTS severity graded using US cutoff values. Ultrasound can be used to grade the severity of CTS with a 75% to 85% specificity but low sensitivity. A cutoff value of 13 mm² can be used to classify CTS as severe.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Inflammatory biomarkers as a part of diagnosis in diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN), a chronic neurological complication of diabetes mellitus, remains scantily addressed area of research. Many lacunae in the temporal sequence between cause and effect of DPN still remain unfilled and therefore treatment of DPN remains unsatisfactory. This is largely due to the conventional glucocentric focus to resolve the problem. This focus over hyperglycemia should be shifted to consider, chronic low grade inflammation as the major determinant in DPN. Rapidly emerging evidences from recent studies suggest that chronic low grade inflammation leads to the activation of innate immune system response, loss of insulin signaling and insulin resistance, endoplasmic reticulum stress, mitochondrial stress, leading to production of kinases like protein kinase C, mitogen activated protein kinase and jun-N-terminal kinase, pro-inflammatory cytokines and inter leukins-1b, 2, 6 and 8, tumour necrosis factor-alpha and other chemokines, leading to DPN. These biomarkers can be early predictors of DPN and therefore should be the focus of work testing their clinical utility to identify high-risk individuals as well as perhaps to target interventions. In this paper, we would like to review all the aspects of DPN, laying greater emphasis on inflammatory biomarkers as a tool for early diagnosis of DPN and the possible research approaches to address it satisfactorily.

Comparison of the Diagnostic Performance of Strain Elastography and Shear Wave Elastography for the Diagnosis of Carpal Tunnel Syndrome

OBJECTIVES

To compare the diagnostic performance between strain elastography and shear wave elastography (SWE) for the diagnosis of carpal tunnel syndrome (CTS).

METHODS

Between July 2018 and June 2019, 66 consecutive patients with 95 imaged wrists underwent wrist ultrasound, including grayscale ultrasound, strain elastography, and SWE, because of the suspicion of CTS. During wrist ultrasound, the cross-sectional area (CSA), strain ratio, elasticity, and shear wave velocity of each median nerve were measured at the proximal carpal bone level (scaphoid to pisiform). The variables were compared between the normal and CTS groups by using the independent t test, and subgroup analyses were performed using one-way analysis of variance. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of each variable.

RESULTS

CSA, elasticity, and shear wave velocity showed significant intergroup differences (P < 0.001, P < 0.001, and P = 0.002, respectively). However, the strain ratio showed no statistically significant intergroup difference (P = 0.639). In the subgroup analyses, elasticity showed significantly higher values in the severe group than in the mild and moderate groups (P < 0.001 and P = 0.001, respectively). Other parameters showed no significant differences among the different subgroups. The areas under the ROC curve were 0.823 for CSA, 0.772 for elasticity, and 0.779 for shear wave velocity. The differences in the areas under the ROC curve among CSA, elasticity, and shear wave velocity were not statistically significant (all P > 0.05).

CONCLUSIONS

SWE has a good diagnostic value in CTS. In particular, elasticity can discriminate the severe group from the other groups.

Clinical predictors of surgical outcomes of severe carpal tunnel syndrome patients: utility of palmar stimulation in a nerve conduction study

Background

Carpal tunnel syndrome is a common peripheral nerve compression disorder. However, there is no established opinion regarding the predictors of symptom improvement after surgery. This study aimed to identify the predictors of surgical outcomes of severe carpal tunnel syndrome patients.

Methods

In the patients who underwent a carpal tunnel syndrome surgery, we selected the patients who had a preoperative Bland’s classification of grade 5 or 6, and assessed for the changes in Bland’s classification grade before and after surgery. Those who showed improvement from preoperative grades 5–6 to postoperative grades 1–4 comprised the improvement group. In contrast, those who did not show improvement and had postoperative grades 5 or 6 comprised the non-improvement group. In a nerve conduction study, amplitudes of the compound muscle action potential and sensory nerve action potential of the palms were assessed between the improvement and non-improvement groups.

Results

Among the 60 hands of 46 patients who had a preoperative Bland’s classification of grade 5 or 6, 49 hands of 37 patients comprised the improvement group, and 11 hands of 9 patients comprised the non-improvement group. The amplitudes of the compound muscle action potential and sensory nerve action potential of the palms before surgery were significantly higher in the improvement group. The degree of improvement in Bland’s classification grade was correlated with the degree of clinical symptom improvement.

Conclusions

Amplitudes of compound muscle action potential and sensory nerve action potential before surgery induced by palmar stimulation can predict improvements in nerve conduction study scores and clinical findings after surgical treatment.

Augmented Diagnostic Accuracy of Ultrasonography for Diagnosing Carpal Tunnel Syndrome Using an Optimised Wrist Circumference-Dependent Cross-Sectional Area Equation

Introduction: In diagnosing carpal tunnel syndrome (CTS) there is no consensus about the upper limit of normal (ULN) of the cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet. A previous study showed wrist circumference is the most important independent predictor for the ULN. In this study we optimised a wrist circumference-dependent ULN equation for optimal diagnostic accuracy and compared it to the generally used fixed ULN of 11 mm².

Methods: CSA and wrist circumference were measured in a prospective cohort of 253 patients (clinically defined CTS) and 96 healthy controls. An equation for the ULN for CSA was developed by means of univariable regression analysis. We calculated z-scores for all patients and healthy controls, and analysed these scores in a ROC curve and a decision plot. Sensitivity and specificity were determined and compared to fixed ULN values.

Results: We found augmented diagnostic accuracy of our newly developed equation y = 0.88 ^* x −4.0, where y = the ULN of the CSA and x = wrist circumference. This equation has a corresponding sensitivity and specificity of 75% compared to a sensitivity of 70% while using a fixed cut-off value of 11 mm² (p = 0.015).

Conclusion: Optimising the regression equation for wrist circumference-dependent ULN cross-sectional area of the median nerve at the wrist inlet might improve diagnostic accuracy of ultrasonography in patients with carpal tunnel syndrome and seems to be more accurate than using fixed cut-off values.

Relative Motion of the Connective Tissue in Carpal Tunnel Syndrome: The Relation with Disease Severity and Clinical Outcome

Excursion of the median nerve and the surrounding subsynovial connective tissue (SSCT) is diminished in patients with carpal tunnel syndrome (CTS). This study sought to determine if SSCT excursion could be utilized to predict surgical outcome. Idiopathic CTS patients were reviewed with ultrasound and electrodiagnostic tests at baseline. A speckle tracking algorithm was used to determine SSCT relative to tendon motion (shear index). Analysis of variance tests were used to compare SSCT motion with disease severity at baseline. Adjusted linear regressions were used to test the association with patient-reported outcome. A total of 90 CTS patients were analyzed and found to have an average shear index of 79% (95% confidence interval: 76.3%-81.6%). SSCT motion was lower in CTS patients with increasing electrophysiological severity (p = 0.0475). There was no significant association of pre-operative SSCT motion with symptomatic improvement (p = 0.268). Overall, SSCT motion is decreased in CTS patients, but exhibits limited correlation with clinical severity.

High-resolution ultrasonography in carpal tunnel syndrome: role of ancillary criteria in diagnosis and response to steroid injection

OBJECTIVES

(1) Development and validation of a composite ultrasound score (cUSS) for the diagnosis of carpal tunnel syndrome (CTS). (2) To predict treatment response after local corticosteroid injection.

METHODS

Wrists of CTS patients and controls were evaluated with high-resolution ultrasound and cross-sectional area of median nerve at carpal tunnel inlet (CSAp) and outlet (CSAd) and bowing of flexor retinaculum (FRB), flexor tenosynovitis, and intraneural vascularity and echogenicity changes were noted. Patients were prospectively followed after ultrasound-guided corticosteroid injection.

RESULTS

We studied 479 wrists of 141 patients and 99 controls. Optimal cut-offs for diagnosing CTS were 9.5 mm² and 10.5 mm², respectively, for CSAp and CSAd. A cUSS consisting of the following parameters was developed: age, CSAp, CSAd, FRB, and flexor tenosynovitis and echogenicity changes. External validation of cUSS yielded sensitivity, specificity, and diagnostic accuracy of 91.7%, 87.1%, and 89.8%, respectively. Treatment responses from 88 injections (median duration of follow-up of 6 months) were available with satisfactory initial responses in 69.32% (61/88) and relapses in 30.86% (25/81). Median time to relapse was 2 months. Initial response was predicted by FRB (odds ratio (OR): 5.43, 95% confidence interval (CI): 1.45-20.3, p = 0.012). Relapse was predicted by age (hazard ratio (HR) 1.168, 95% CI: 1.076-1.268, p = 0.0002), male gender (HR: 8.1.02, 95% CI: 2.394-27.422, p = 0.0007), FRB, (HR: 46.982, 95% CI: 5.048-437.293, p = 0.0008), and higher body mass index (HR: 0.238, 95% CI: 0.064-0.892, p = 0.0332).

CONCLUSIONS

The developed cUSS has a diagnostic accuracy of 88% for diagnosing CTS. Ultrasound parameters could predict both initial treatment response and relapse.

KEY POINTS

• Anatomical ultrasound parameters in addition to nerve cross-sectional area is important for diagnosis of CTS. • A composite US score for diagnosis of CTS was developed with accuracy 88.6%. • Bowing of flexor retinaculum predicts short and long term response to local steroid injection.

A Review of Carpal Tunnel Syndrome and Its Association with Age, Body Mass Index, Cardiovascular Risk Factors, Hand Dominance, and Sex

Carpal tunnel syndrome (CTS) is one of the most common compressive, canalicular neuropathies of the upper extremities, causing hand pain and impaired function. CTS results from compression or injury of the median nerve at the wrist within the confines of the carpal tunnel. Parameters such as age, sex, and body mass index (BMI) could be risk factors for CTS. This research work aimed to review the existing literature regarding the relationship between CTS and possible risk factors, such as age, sex, BMI, dominant hand, abdominal circumference, respiratory rate, blood pressure, and cardiac rate to determine which ones are the most influential, and therefore, take them into account in subsequent applied research in the manufacturing industry. We performed a literature search in the PubMed, EBSCO, and ScienceDirect databases using the following keywords: carpal tunnel syndrome AND (age OR sex OR BMI OR handedness OR abdominal circumference OR respiratory rate OR blood pressure OR cardiac rate). We chose 72 articles by analyzing the literature found based on selection criteria. We concluded that CTS is associated with age, female sex, and high BMI. Trends and future challenges have been proposed to delve into the relationship between risk factors and CTS, such as correlation studies on pain reduction, analysis of weight changes to predict the severity of this pathology, and its influence on clinical treatments.

Electrodiagnostic Studies and Ultrasound Cross-Sectional Area of the Median Nerve in Patients With Isolated Cervical Radiculopathy

Purpose

Although the literature has shown that the cross-sectional area (CSA) of the carpal tunnel on ultrasound is enlarged in patients with carpal tunnel syndrome, it does not provide information regarding whether proximal nerve pathology, such as that seen in cervical radiculopathy, increases the CSA of the median nerve.

Methods

In this study, 15 patients were enrolled who had a clinical diagnosis of cervical radiculopathy but not carpal tunnel syndrome. All patients underwent electrodiagnostic studies and ultrasound measurement of the CSA of the median nerve.

Results

Increased median nerve CSA was seen in 1 of 15 patients (7%). Positive findings of cervical radiculopathy were found in 7 patients (47%) by electrodiagnostic studies.

Conclusions

In patients clinically diagnosed with isolated cervical radiculopathy, the vast majority have normal median nerve CSA measured on ultrasound.

Type of study/level of evidence

Prognostic IV.

Median nerve ultrasound in carpal tunnel syndrome with normal electrodiagnostic tests

INTRODUCTION

To evaluate the ultrasound findings of the median nerve in patients with clinical assigned carpal tunnel syndrome but normal nerve conduction studies.

METHODS

This prospective, cross-sectional study involved 41 patients (51 hands) with clinically assigned CTS and normal nerve conduction studies and 20 healthy controls (30 hands). Ultrasonography was performed in all participants, and cross-sectional area (CSA), hypoechogenicity, and mobility of the median nerve were evaluated. All patients were assessed with Boston Carpal Tunnel Questionnaire (BCTQ).

RESULTS

CSA of the median nerve in the wrist was significantly higher in the patient group when compared to the control group. Echogenicity and mobility were significantly decreased in the patient group. Ultrasound abnormalities were positively correlated with clinical features. A significant correlation was observed among sensory loss, provocative tests, body mass index, BCTQ, and high CSA.

CONCLUSION

US can help the clinicians with the diagnosis of carpal tunnel syndrome in patients with clinical symptoms but negative nerve conduction study results.

A Comparison of Changes in Median Nerve Cross-sectional Area Between Endoscopic and Mini-Open Carpal Tunnel Release

Purpose

The purpose of this study was to determine whether there is a difference in the change in cross-sectional area (CSA) of the median nerve in patients undergoing carpal tunnel release (CTR) based on surgical technique and whether this change is associated with changes in patient-reported outcomes evaluated using the Carpal Tunnel Syndrome Assessment Questionnaire.

Methods

Individuals with carpal tunnel syndrome were evaluated with ultrasound and the CTSAQ before and 6 weeks after surgery. Patients were eligible for inclusion if they underwent either a mini-open CTR (MOCTR) or endoscopic CTR (ECTR). A single surgeon performed all surgeries. Changes in median nerve CSA, Carpal Tunnel Syndrome Assessment Questionnaire scores, and their associated surgical technique (MOCTR vs ECTR) were analyzed.

Results

A total of 77 patients were enrolled, 13 of whom were lost to follow-up, which left 64 for analysis. Of those, 42 patients underwent ECTR and 22 MOCTR. Mean age was 55 years; there were 52 women and 12 men. Mean changes in CSA for endoscopic and mini-open techniques from before to 6 weeks after surgery were –1.9 mm² (95% confidence interval [CI], –1.1 to –2.7) and +0.6 mm² (95% CI, –1.6 to 0.4), respectively. Mean Symptom Severity Scores improved after endoscopic and mini-open release by 1.7 (95% CI, 1.4–2.1) and 1.5 (95% CI, 1.2–1.9), respectively. Mean Functional Status Scores improved after endoscopic and mini-open release by 1.2 (95% CI, 0.9–1.9) and 0.7 (95% CI, 0.03–1.3), respectively.

Conclusions

Patients undergoing ECTR demonstrated decreased median nerve CSA, whereas those undergoing MOCTR demonstrated increased median nerve CSA at 6 weeks. All patients undergoing surgical intervention demonstrated improvement in both Symptom Severity Scores and Functional Status Scores after surgery. Whereas both techniques successfully improve patient outcome scores, an increase in CSA after MOCTR may be seen in the initial postoperative period, potentially contributing to a slower short-term improvement in outcome in functional scores compared with ECTR.

Type of study/level of evidence

Therapeutic IV.

Agreement Between High-Resolution Ultrasound and Electro-Physiological Examinations for Diagnosis of Carpal Tunnel Syndrome in the Indonesian Population

Carpal tunnel syndrome (CTS) is a disorder of the wrist due to narrowing of the carpal tunnel. It can be caused by trauma or tumors in the tunnel resulting in compression of the median nerve. This disorder is often diagnosed with early symptoms such as tingling, numbness, and weakness that subsequently lead to hand muscle atrophy. While ultrasonography (USG) is one of the diagnostic methods of CTS, neurophysiological diagnosis, such as with nerve conduction study (NCS), is standard in clinics where the necessary equipment is available. This cross-sectional study aimed to compare USG diagnostic values with NCS results to determine USG efficacy for diagnosis of CTS. Data on medical history, physical examination, ultrasound results, and NCS examination from patients who had been diagnosed with CTS at a regional general hospital in Indonesia were collected. In total, 46 patients participated in the study and data were compared using 2 × 2 table analyses and the kappa statistic. Results showed USG sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and accuracy values of 88.5, 65, 76.6, 81.25, 2.52, 0.17, and 78.2%, respectively (p < 0.005). Comparison between NCS and the USG assessment obtained a kappa coefficient of κ = 0.71 and showed high agreement (κ = 0.410.60). In conclusion, the diagnostic value of USG compared to NCS is acceptable. Therefore, USG examination is a feasible CTS diagnostic alternative for clinicians who do not have access to an electrodiagnostic facility.

False-Positive Rates for Nerve Conduction Studies and Ultrasound in Patients Without Clinical Signs and Symptoms of Carpal Tunnel Syndrome

PURPOSE

The purpose of the study was to determine the rate of false positives for nerve conduction studies (NCSs) and ultrasound (US) in a population without signs and symptoms of carpal tunnel syndrome (CTS) using a CTS-6 score of 0 as the reference standard.

METHODS

Patients were included in this study if they were referred for NCSs for a reason other than CTS (cubital tunnel syndrome and/or cervical radiculopathy) and they had a CTS-6 score of 0. An US measurement of the cross-sectional area (CSA) of the median nerve at the level of the carpal tunnel inlet was performed by a certified ultrasound technician. An a priori CSA cutoff of 10 mm² or greater measured using US at the carpal tunnel inlet qualified as a positive diagnosis. The NCSs were performed and interpreted according to national standards by a certified electrodiagnostician. All patients in this study were considered to not have a diagnosis of CTS based on the CTS-6 of 0.

RESULTS

Forty hands with a CTS-6 of 0 were included in this study. The US was positive in 9 of 40(23%) and NCS was positive in 17 of 40 (43%). There were only 2 patients with a false-positive US that did not also have a positive NCS. However, there were 11 patients who had a false-positive NCS that did not have a positive US.

CONCLUSIONS

This prospective cohort series has demonstrated that US has a lower false-positive rate than NCSs in asymptomatic patients as measured by the CTS-6 diagnostic tool. Studies with a low false-positive rate are preferred when ordering a confirmatory diagnostic test. Therefore, if a confirmatory diagnostic test is desired, we recommend that US be used rather than NCSs.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Correlation of ultrasound cross-sectional area of the median nerve, nerve conduction studies and 2-point discrimination

INTRODUCTION

The purpose of this study was to determine the correlation between a measure of physical performance, a measure of physiology and a measure of anatomy in the setting of carpal tunnel syndrome (CTS).

METHODS

A retrospective review of 215 consecutive patients with suspected CTS was conducted. All patients were evaluated with static 2-point discrimination (2PD), ultrasound (US) measurement of the median nerve cross-sectional area (CSA), and nerve conduction studies (NCS). Correlations between 2PD and US and NCS parameters were calculated. The ability of US/NCS to predict 2PD was evaluated.

RESULTS

Analysis failed to prove a statistically significant correlation between 2PD and median nerve CSA. A weak correlation was detected between 2PD and NCS parameters. When 2PD was used as a reference standard, NCS parameters combined had the greatest sensitivity, followed by US.

CONCLUSIONS

Currently used diagnostic tests (NCS and US) correlate poorly with 2PD. Muscle Nerve 000: 000-000, 2018 Muscle Nerve 59:236-239, 2019.

Ultrasonographic reference values for the median nerve at the level of pronator teres muscle

PURPOSE

The purpose of this study was to investigate the ultrasonographic reference values for diameters and cross-sectional area (CSA) of the median nerve between the two heads of the pronator teres muscle in healthy population as well as to correlate the findings with height, weight, sex and age.

METHODS

Fifty-five healthy Caucasian volunteers (110 median nerves) were included in this study. The reference range (mean ± 2 standard deviations; 2.5th-97.5th quintiles) and the upper limit of side-to-side difference of the median nerve between the two heads of the pronator teres muscle were investigated using high-frequency ultrasound. The effects of age, sex, height, handedness, and body mass index (BMI) were examined.

RESULTS

The mean age was 39.4 ± 10.6 years (range 18-75 years). The mean ± 2SD of the median CSA was 4.9-12.9 mm². The upper limit of normal side-to-side difference was 3.0 mm². The differences between genders and between the dominant and non-dominant hands were not significant. The mean antero-posterior and transverse diameters were 7.2 ± 1.5 and 10.7 ± 2.4 mm, respectively. Significant correlations were observed between the dominant-side CSA and BMI (r = 0.33; p = 0.01) and age (r = 0.31; p = 0.02). The correlation between the CSA and height (r = 0.19; p = 0.16) was not significant.

CONCLUSIONS

The measurements obtained in this study are of importance for examining median nerve entrapments in the forearm using high-frequency ultrasound. Age and BMI showed to be correlated with median nerve CSA; while gender and height were not.

Effectiveness of ultrasonography and nerve conduction studies in the diagnosing of carpal tunnel syndrome: clinical trial on accuracy

BACKGROUND

The aim of this study was to evaluate the effectiveness of two diagnostic tests routinely used for diagnosing carpal tunnel syndrome (CTS)-ultrasonography (US) and nerve conduction studies (NCS)-by comparing their accuracy based on surgical results, with the remission of paresthesia as the reference standard.

METHODS

We enrolled 115 patients, all of the female gender with a high probability of a clinical diagnosis of CTS. All patients underwent US and NCS for a diagnosis and subsequent surgical treatment. As a primary outcome, the accuracy of the US and NCS diagnoses was measured by comparing their diagnoses compared with those determined by the surgical outcomes. Their accuracy was secondarily evaluated based on before and after scores of the Boston Carpal Tunnel Questionnaire (BCTQ).

RESULTS

Overall, 104 patients (90.4%) were diagnosed with CTS by the surgical reference standard, 97 (84.3%) by NCS, and 90 (78.3%) by US. The concordance of NCS and surgical treatment (p < 0.001; kappa = 0.648) was superior to that of US and surgical treatment (p < 0.001; kappa = 0.423). The sensitivity and specificity of US and NCS were similar (p = 1.000 and p = 0.152, respectively: McNemar's test). The BCTQ scores were lower after surgery in patients diagnosed by both US and NCS (p < 0.001and p < 0.001, respectively: analysis of variance).

CONCLUSIONS

US and NCS effectively diagnosed CTS with good sensitivity but were not effective enough to rule out a suspicion of CTS.

TRIAL REGISTRATION

This study was registered at September, 10 th, 2015, and the registration number was NCT02553811 .

Inter-Rater and Intra-Rater Reliability of Sonographic Median Nerve and Wrist Measurements

Background:

Electrophysiologic studies have been considered the “gold standard” in diagnosing carpal tunnel syndrome (CTS); however, reports of false-negative results, as well as discomfort for the patient during the procedure has paved the use of ultrasound, being a painless and cost-efficient tool, as an alternative means for its diagnosis. Various ultrasound parameters assessing the median nerve and wrist dimensions have been described, but description of landmarks to assess these in a reliable manner has been lacking.

Methodology:

A systematic search of different databases yielded data regarding ultrasound parameters for CTS diagnosis, the landmarks used, and presence of reliability testing. Based on this, three sonologists discussed the external and sonographic landmarks that will be used in measuring the median nerve measurements, bowing of the flexor retinaculum and the carpal tunnel dimensions. A pilot test with two consecutive healthy participants using the discussed ultrasound parameters was carried out, and results were subjected to inter- and intra-rater reliability testing. Modifications were accordingly made on the acquisition of ultrasound image using external landmarks. The reliability testing proper was done with ten consecutive healthy participants.

Results:

Based on the systematic review and the pilot study, external landmarks were used to locate the median nerve in the forearm, carpal tunnel inlet and outlet. For the forearm measurement, it was taken 10 cm proximal from the distal palmar crease. The distal palmar crease was the external landmark used for the carpal tunnel inlet, while for the carpal tunnel outlet; it was measured 1 cm distal to the distal palmar crease. Instead of using the inner edge of the hook of hamate and trapezium, the apices of these bones were used as the landmarks in measuring the carpal tunnel outlet dimensions. There was excellent intra-rater reliability (mid-forearm, carpal tunnel inlet and outlet) except for the following: cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet and outlet; and bowing of the flexor retinaculum. All the parameters had an excellent inter-rater reliability measured at the three levels (intraclass correlation [ICC]: Of 0.77–0.99) except for CSA of the median nerve at the levels of the forearm (fair-to-good with ICC of 0.71) and the carpal tunnel inlet (fair-to-good reliability of ICC: 0.43).

Conclusion:

There was an improved inter- and intra-rater reliability when external landmarks were used instead of sonographic landmarks.

Comparison of Median Nerve Cross-sectional Area on 3-T MRI in Patients With Carpal Tunnel Syndrome

This study correlated morphologic abnormalities of idiopathic carpal tunnel syndrome (CTS) with the severity of CTS using 3-T magnetic resonance imaging (MRI). The relationship of the severity of CTS and the cross-sectional area of the median nerve (CSA) was assessed at several levels. Seventy wrists of 35 patients (27 women and 8 men) with unilateral idiopathic CTS underwent nerve conduction study and 3-T MRI of the wrist. The CSA at 4 levels (distal radioulnar joint, body of scaphoid, tubercule of scaphoid, and hook of hamate) and the thickness of the transverse carpal ligament at 3 levels in both affected and unaffected hands were measured using 3-T MRI and correlated with the severity of CTS assessed with distal motor latency. The CSA in the affected hand at the scaphoid body level was significantly higher than in the unaffected hand. The CSA at the scaphoid body level was positively correlated with distal motor latency in the affected hand. The CSA in the affected hand at the scaphoid tubercule level was significantly lower than in the unaffected hand. The CSA had a negative correlation with distal motor latency at the scaphoid tubercule level. The CSA at the distal radioulnar joint and the hamate hook was not significantly different between the affected hand and the unaffected hand. The CSA at the distal radioulnar joint level and hook level were not correlated significantly with distal motor latency in the affected hand. The mean CSA of the affected hand at the scaphoid body level was highest in 4 levels. [Orthopedics. 2017; 40(1):e77-e81.].

A Survey of the Use of Ultrasound by Upper Extremity Surgeons

Background: Ultrasound is a versatile imaging modality that can be used by upper extremity surgeons for diagnostic purposes and guided injections. The perceptions of ultrasound for diagnosis and treatment among upper extremity surgeons and its barriers for adoption have not been formally surveyed. The purpose of this study is to determine the current usage of musculoskeletal ultrasound for diagnostic purposes and guided injections by upper extremity surgeons and their reasons for using it or not using it in practice. Methods: A 22-question survey was distributed to the American Society for Surgery of the Hand (ASSH). The survey questions consisted of respondent characteristic questions and questions pertaining to the use of ultrasound. Chi-square analysis was performed to assess for a difference in ultrasound usage across respondent characteristics. Results: Three hundred four (43%) answered that they have an ultrasound machine in their office; Fifty-one percent (362) of the respondents use ultrasound for diagnostic purposes. Fifty-five (8%) of the survey respondents use ultrasound to diagnose carpal tunnel syndrome; 168 (23.5%) respondents reported that they use ultrasound for guided injections. There was a statistically significant difference between access to an ultrasound machine in the office by practice setting and use of ultrasound for diagnostic purposes by practice setting. Conclusions: The use of ultrasound by upper extremity surgeons is split for diagnostic purposes, with fewer surgeons using ultrasound to diagnose carpal tunnel syndrome and guided injections. Ultrasound machine availability and the use of ultrasound for diagnosis appear to be influenced by practice setting.

Review of Ultrasonography in the Diagnosis of Carpal Tunnel Syndrome and a Proposed Scanning Protocol

Carpal tunnel syndrome is the most common peripheral compressive neuropathy. Ultrasonography (US) is an emerging technology that can be used in the diagnosis of carpal tunnel syndrome. Although the cross-sectional area is the most studied and validated measurement for carpal tunnel syndrome, there is no standardized neuromuscular US scanning protocol. We review the most studied neuromuscular US characteristics and protocols in the evaluation of carpal tunnel syndrome and propose a standardized protocol for evaluating carpal tunnel syndrome with neuromuscular US based on current literature.

Baseline Characteristics of the Median Nerve on Ultrasound Examination

Background: Previous studies using ultrasound for diagnosis of carpal tunnel syndrome have reported on relatively small series of patients, leading to large standard deviations and/or confidence intervals for the mean cross-sectional area of the median nerve. The purpose of this study is to define the CSA of the median nerve in a large cohort of patients. Methods: Patients (n = 175) without history of carpal tunnel release were recruited. All participants were evaluated using the Carpal Tunnel Syndrome-6 questionnaire, a validated clinical diagnostic tool, with a score of 12 or greater considered positive for CTS. Ultrasound examination was performed on both wrists of all participants using a 13-6 MHz linear array transducer. Results: The mean median nerve CSA was significantly larger (P < .001) for patients with a positive (mean = 11.16, SD = 2.51) versus negative CTS-6 result (mean = 6.91, SD = 2.06). There was a significant correlation (.527, P < .001, n = 349) between CSA and CTS-6 score. Logistic regression analysis determined that a CSA of 10 mm2 optimized sensitivity and specificity at 80% and 88%, respectively. Accuracy was 87.9%. Conclusions: A significant difference in mean CSA was found between patients with and without CTS. Median nerve CSA showed a statistically significant positive correlation with CTS-6. Similar to prior studies, a CSA of 10 mm2 was determined to be the optimal cutoff. In this large series of patients, ultrasound was a sensitive, specific, and accurate test for confirmation of a clinical diagnosis of CTS.

Detection of Intraneural Median Nerve Microvascularity Using Contrast-Enhanced Sonography: A Pilot Study

OBJECTIVES

Demonstrating vascularity within the human median nerve may be difficult using power Doppler sonography. To this end, a pilot study documenting contrast-enhanced vascularity of the median nerve was conducted.

METHODS

Patients undergoing contrast-enhanced transthoracic echocardiography were recruited for this study (n = 24). During echocardiography, a simultaneous contrast-enhanced sonographic examination of the median nerve was conducted. The study and study protocol were built from preclinical evidence. Image analysis was based on the power Doppler pixel intensity within a defined region of interest to obtain quantitative data representing the average pixel intensity, maximum pixel intensity, and power Doppler pixel dot count. Semiquantitative data representing the power Doppler dot count grading were also obtained.

RESULTS

Spearman correlations between analytical methods showed strong positive, statistically significant (P< .05) correlations between the average pixel intensity and maximum pixel intensity and between the power Doppler dot count and dot count grading. Statistically significant increases in the average pixel intensity and power Doppler dot count were seen at all but 1 time point throughout the contrast-enhanced sonographic examination when compared to precontrast administration. Statistically significant increases in the maximum pixel intensity were seen at all but 4 time points.

CONCLUSIONS

These pilot results represent early evidence that contrast-enhanced sonography can be used to image median nerve vascularity. In this convenience sample, median nerve contrast-enhanced sonographic data collection was feasible, safe, and consistent.

Correlation Between the Severity of Diabetic Peripheral Polyneuropathy and Glycosylated Hemoglobin Levels: A Quantitative Study

Objective

To investigate risk factors for diabetic peripheral polyneuropathy and their correlation with the quantified severity of nerve dysfunction in patients with diabetes mellitus (DM).

Methods

A total of 187 diabetic patients with clinically suspected polyneuropathy (PN) were subclassified into 2 groups according to electrodiagnostic testing: a DM-PN group of 153 diabetic patients without electrophysiological abnormality and a DM+PN group of 34 diabetic patients with polyneuropathy. For all patients, age, sex, height, weight, duration of DM, and plasma glycosylated hemoglobin (HbA1c) level were comparatively investigated. A composite score was introduced to quantitatively analyze the results of the nerve conduction studies. Logistic regression analysis and multiple regression analysis were used to evaluate correlations between significant risk factors and severity of diabetic polyneuropathy.

Results

The DM+PN group showed a significantly higher HbA1c level and composite score, as compared with the DM-PN group. Increased HbA1c level and old age were significant predictive factors for polyneuropathy in diabetic patients (odds ratio=5.233 and 4.745, respectively). In the multiple linear regression model, HbA1c and age showed a significant positive association with composite score, in order (β=1.560 and 0.253, respectively).

Conclusion

Increased HbA1c level indicative of a state of chronic hyperglycemia was a risk factor for polyneuropathy in diabetic patients and a quantitative measure of its severity.

Grey-scale sonography and sonoelastography for diagnosing carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common peripheral entrapment neuropathy of the median nerve at wrist level, and is thought to be caused by compression of the median nerve in the carpal tunnel. There is no standard quantitative reference for the diagnosis of CTS. Grey-scale sonography and sonoelastography (SEL) have been used as diagnostic tools. The most commonly agreed findings in grey-scale sonography for the diagnosis of CTS is enlargement of the median nerve cross-sectional area (CSA). Several authors have assessed additional parameters. “Delta CSA” is the difference between the proximal median nerve CSA at the pronator quadratus and the maximal CSA within the carpal tunnel. The “CSA ratio” is the ratio of CSA in the carpal tunnel to the CSA at the mid forearm. These additional parameters showed better diagnostic accuracy than CSA measurement alone. Recently, a number of studies have investigated the elasticity of the median nerve using SEL, and have shown that this also has diagnostic value, as it was significantly stiffer in CTS patients compared to healthy volunteers. In this review, we summarize the usefulness of grey-scale sonography and SEL in diagnosing CTS.

Assessment of Median Nerve Mobility by Ultrasound Dynamic Imaging for Diagnosing Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by median nerve entrapment at the wrist and the resulting median nerve dysfunction. CTS is diagnosed clinically as the gold standard and confirmed with nerve conduction studies (NCS). Complementing NCS, ultrasound imaging could provide additional anatomical information on pathological and motion changes of the median nerve. The purpose of this study was to estimate the transverse sliding patterns of the median nerve during finger movements by analyzing ultrasound dynamic images to distinguish between normal subjects and CTS patients. Transverse ultrasound images were acquired, and a speckle-tracking algorithm was used to determine the lateral displacements of the median nerve in radial-ulnar plane in B-mode images utilizing the multilevel block-sum pyramid algorithm and averaging. All of the averaged lateral displacements at separate acquisition times within a single flexion–extension cycle were accumulated to obtain the cumulative lateral displacements, which were curve-fitted with a second-order polynomial function. The fitted curve was regarded as the transverse sliding pattern of the median nerve. The R² value, curvature, and amplitude of the fitted curves were computed to evaluate the goodness, variation and maximum value of the fit, respectively. Box plots, the receiver operating characteristic (ROC) curve, and a fuzzy c-means clustering algorithm were utilized for statistical analysis. The transverse sliding of the median nerve during finger movements was greater and had a steeper fitted curve in the normal subjects than in the patients with mild or severe CTS. The temporal changes in transverse sliding of the median nerve within the carpal tunnel were found to be correlated with the presence of CTS and its severity. The representative transverse sliding patterns of the median nerve during finger movements were demonstrated to be useful for quantitatively estimating median nerve dysfunction in CTS patients.

The Reliability of Ultrasound Measurements of the Median Nerve at the Carpal Tunnel Inlet

PURPOSE

To determine the interrater and intra-rater reliability of ultrasound (US) measurement of the cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet.

METHODS

Three examiners of varying levels of experience performed US measurements of the CSA of the median nerve at the carpal tunnel inlet of both wrists of 11 healthy volunteers. Each examiner was blinded to the measurements of the other examiners. The measurements were repeated 2 weeks later in random order to test intra-rater reliability. The Lin concordance correlation coefficient (LCCC) for interrater and intra-rater reliability was calculated.

RESULTS

The overall inter-rater LCCC was 0.59 (95% confidence interval [CI], 0.41-0.73). Intra-rater LCCC varied based on examiner experience. The senior author had an intra-rater LCCC of 0.91 (95% CI, 0.80-0.96), the hand fellow had an intra-rater LCCC of 0.45 (95% CI, 0.17-0.66), and the first-year resident had an intra-rater LCCC of 0.78 (95% CI, 0.55-0.90).

CONCLUSIONS

There is moderate agreement among examiners of varying levels of experience when measuring the CSA of the median nerve at the carpal tunnel inlet. Examiner experience affected intra-rater reliability of measurements; an experienced examiner had nearly perfect agreement compared with moderate agreement for less experienced examiners.

High-frequency ultrasound in carpal tunnel syndrome: assessment of patient eligibility for surgical treatment

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and a frequent cause of sick leaves because of work-related hand overload. That is why an early diagnosis and adequate treatment (conservative or surgical) are essential for optimal patient management.

In the Clinic. Carpal Tunnel Syndrome

This issue provides a clinical overview of carpal tunnel syndrome, focusing on screening and prevention, diagnosis, and treatment. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.

Comparative study between physical examination, electroneuromyography and ultrasonography in diagnosing carpal tunnel syndrome

OBJECTIVE

To evaluate the sensitivity of electromyography and ultrasonography in diagnosing carpal tunnel syndrome (CTS), in comparison with physical examination, which is considered to be the gold standard.

METHODS

In this cross-sectional study, the medical files of 56 patients with 70 hands affected by CTS who were attended between March 2010 and June 2012 were reviewed. The study included patients with a clinical diagnosis of CTS. The sensitivity of the complementary examinations was analyzed and compared with physical examination.

RESULTS

Nocturnal symptoms were found in 96.4%, thenar atrophy in 62.5% and abnormal sense of touch in 50%. The sensitivities found were: ultrasonography, 67.1% (95% CI: 55.7%-78.6%); an association of physical examination tests, 95.7% (95% CI: 90.0%-100%); and electromyography, 98.6% (95% CI: 95.7%-100%). The presence of atrophy, abnormalities of the sense of touch and longer-duration symptoms increased the sensitivity of ultrasonography and physical examination.

CONCLUSION

The sensitivity of ultrasonography for CTS was lower than that of electromyography and physical examination.

Computer keyboarding biomechanics and acute changes in median nerve indicative of carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome is a common and costly peripheral neuropathy. Occupations requiring repetitive, forceful motions of the hand and wrist may play a role in the development of carpal tunnel syndrome. Computer keyboarding is one such task, and has been associated with upper-extremity musculoskeletal disorder development. The purpose of this study was to determine whether continuous keyboarding can cause acute changes in the median nerve and whether these changes correlate with wrist biomechanics during keyboarding.

METHODS

A convenience sample of 37 healthy individuals performed a 60-minute typing task. Ultrasound images were collected at baseline, after 30 and 60 min of typing, then after 30 min of rest. Kinematic data were collected during the typing task. Variables of interest were median nerve cross-sectional area, flattening ratio, and swelling ratio at the pisiform; subject characteristics (age, gender, BMI, wrist circumference, typing speed) and wrist joint angles.

FINDINGS

Cross-sectional area and swelling ratio increased after 30 and 60 min of typing, and then decreased to baseline after 30 min of rest. Peak ulnar deviation contributed to changes in cross-sectional area after 30 min of typing.

INTERPRETATION

Results from this study confirmed a typing task causes changes in the median nerve, and changes are influenced by level of ulnar deviation. Furthermore, changes in the median nerve are present until cessation of the activity. While it is unclear if these changes lead to long-term symptoms or nerve injury, their existence adds to the evidence of a possible link between carpal tunnel syndrome and keyboarding.