Ratio and difference of the cross-sectional area of median nerve to ulnar nerve in diagnosing carpal tunnel syndrome: a case control study

Chang, Yu-Hsun; Hsieh, Tsung-Cheng; Tzeng, I‐Shiang; Chiu, Valeria; Huang, Pei-Jung; Horng, Yi-Shiung

doi:10.1186/s12880-019-0351-3

Cited by 21 publications

(20 citation statements)

References 41 publications

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“…The diagnostic value of wrist median nerve CSA vs. wrist-to-forearm ratio showed inconsistent results in literature ( 30 , 31 ). A cross-sectional study published in 2019 by Chang et al suggests the ulnar nerve compared to the median nerve at wrist level could serve as internal control by using median-to-ulnar-nerve difference instead of the median-to-ulnar-nerve ratio ( 32 ).…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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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 mm 2. 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 cutoff value of 11 mm 2 (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 cutoff values.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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“…In most studies, ultrasonography is used to diagnose CTS according to the following criteria: (1) increased CSA of the median nerve, (2) increased flattening ratio (FR; the ratio of the length of the long axis to that of the short axis of the median nerve), and (3) increased palmar bowing of the flexor retinaculum [ 6 , 7 ]. Moreover, the swelling ratio (the ratio of the CSA of the median nerve at carpal tunnel to that at the forearm level), and ratio and difference in CSA between the median and ulnar nerves have also been used to accommodate intersubject variations [ 8 , 9 ]. Some studies also observed increased intraneural blood flow in the median nerve on patients’ color or power Doppler ultrasonograms [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of wrist extension on median nerve and flexor tendon excursions in patients with carpal tunnel syndrome: a case control study

Liu

Chen

et al. 2021

BMC Musculoskelet Disord

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Background Reduced gliding ability of the median nerve in the carpal tunnel has been observed in patients with carpal tunnel syndrome (CTS). The purpose of this study was to evaluate the gliding abilities of the median nerve and flexor tendon in patients with CTS and healthy participants in the neutral and 30° extended positions of the wrist and to compare the gliding between the finger flexion and extension phases. Methods Patients with CTS and healthy participants were consecutively recruited in a community hospital. All the subjects received the Boston CTS questionnaire, physical examinations, nerve conduction study (NCS), and ultrasonography of the upper extremities. Duplex Doppler ultrasonography was performed to evaluate the gliding abilities of the median nerve and flexor tendon when the subjects continuously moved their index finger in the neutral and 30° extension positions of the wrist. Results Forty-nine patients with CTS and 48 healthy volunteers were consecutively recruited. Significant differences in the Boston CTS questionnaire, physical examination and NCS results and the cross-sectional area of the median nerve were found between the patients and the healthy controls. The degree of median nerve gliding and the ratio of median nerve excursion to flexor tendon excursion in the CTS group were significantly lower than those in the healthy control group in both the neutral and 30° wrist extension positions. Significantly increased excursion of both the median nerve and flexor tendon from the neutral to the extended positions were found in the CTS group. The ratio of median nerve excursion to flexor tendon excursion was significantly higher in the finger flexion phase than in the extended phase in both groups, and this ratio had mild to moderate correlations with answers on the Boston CTS Questionnaire and with the NCS results. Conclusions Reduced excursion of the median nerve was found in the patients with CTS. The ratio of median nerve excursion to flexor tendon excursion was significantly lower in the patients with CTS than in the healthy volunteers. The median nerve excursion was increased while the wrist joint was extended to 30° in the patients with CTS. Wrist extension may be applied as part of the gliding exercise regimen for patients with CTS to improve median nerve mobilization.

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“…However, using a single cutoff value for the CSA of the median nerve has been argued to underestimate the prevalence rate of CTS, given the variations in body weight, age, and sex among individuals [ 4 , 5 ]. Therefore, alternative methods have been proposed for ultrasound examination of CTS patients.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, alternative methods have been proposed for ultrasound examination of CTS patients. For example, comparative methods such as the swelling ratio and ulnar to median ratio use the median nerve at the forearm level or ulnar nerve at the wrist level as an internal control to improve the diagnostic accuracy [ 4 , 6 – 9 ]. Using power Doppler ultrasonography to evaluate the intraneural vascularity of the median nerve, on the other hand, has also emerged in recent years as another method to assist in diagnosing CTS [ 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of temperature on sonographic images of the median nerve for the diagnosis of carpal tunnel syndrome: a case control study

et al. 2021

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Background In addition to nerve conduction studies (NCSs), ultrasonography has been widely used as an alternative tool for diagnosing carpal tunnel syndrome (CTS). Although the results of NCSs are influenced by local skin temperature, few studies have explored the effects of skin temperature on ultrasonography of the median nerve. Since swelling and intraneural blood flow of the median nerve might be influenced by local temperature changes, the aim of this study was to evaluate the cross-sectional area (CSA) and intraneural blood flow of the median nerve under three skin temperatures (30 °C, 32 °C, 34 °C). Methods Fifty patients with CTS and 50 healthy volunteers were consecutively recruited from a community hospital. Each participant received physical examinations and NCSs and underwent ultrasonography, including power Doppler, to evaluate intraneural vascularity. Results The CSA of the median nerve in the CTS patients was significantly larger than that in the healthy controls at all three temperatures. However, significant differences in the power Doppler signals of the median nerve between the two studied groups were observed only at 30 and 32 °C, not at 34 °C. Conclusion The significant difference in the intraneural vascularity of the median nerve between the patients with CTS and the healthy subjects was lost at higher temperatures (34 °C). Therefore, the results of power Doppler ultrasonography in diagnosing CTS should be cautiously interpreted in patients with a high skin temperature or those who reside in warm environments.

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Ratio and difference of the cross-sectional area of median nerve to ulnar nerve in diagnosing carpal tunnel syndrome: a case control study

Cited by 21 publications

References 41 publications

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

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

Effects of wrist extension on median nerve and flexor tendon excursions in patients with carpal tunnel syndrome: a case control study

Influence of temperature on sonographic images of the median nerve for the diagnosis of carpal tunnel syndrome: a case control study

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