Effect of Wrist Angle on Median Nerve Appearance at the Proximal Carpal Tunnel

Loh, Ping Yeap; Muraki, Satoshi

doi:10.1371/journal.pone.0117930

Cited by 32 publications

(53 citation statements)

References 42 publications

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“…The deformity of the median nerve during wrist flexion or extension has already been shown and the CSA of the median nerve has been reported to decrease during wrist motion [5]. Also, the acute postural changes of the wrist have been reported to increase the median nerve stiffness [3].…”

Section: Discussionmentioning

confidence: 95%

“…A recently published study showed that posture-induced changes could be detected by Shear-Wave Elastography (SWE) at the median nerve [3]. Previous US studies have reported conflicting results on whether median nerve cross-sectional area (CSA) is altered in different wrist postures [4][5][6]. Although the effect of acute postural changes to the median nerve has been studied, the chronic effects of postural changes to the median nerve have not been clearly identified yet.…”

Section: Introductionmentioning

confidence: 99%

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Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Aslan

Analan

2018

Med Ultrason

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Aim: To investigate the effects of chronic flexed wrist posture following spasticity on the elasticity and cross-sectional area (CSA) of the median nerve at the carpal tunnel among chronic stroke patients.Material and method: This prospective study included 24 consecutive patients (mean age, 56.5±11.56 years) with unilateral wrist spasticity following a stroke in a chronic phase. The CSA of the median nerve was measured by ultrasound (US). The elasticity was measured by Virtual Touch tissue imaging quantification (VTIQ; Siemens, Erlangen, Germany). SWV and CSA of the median nerves of the affected and unaffected sides for each patient were compared. The correlations between duration of time since the stroke, SWV and CSA of the median nerve were assessed. The interobserver agreement was assessed.Results: The CSA of the median nerve at the affected side was significantly lower than that of the unaffected side (p = 0.03). The SWV of the median nerve at the affected side was significantly higher than that on the unaffected side (p < 0.001). The interobserver agreement was excellent for both CSA and SWV measurements. There was a negatively fair correlation between CSA at the affected side and duration of time since stroke (r = -0.58, p < 0.05). The SWV of the median nerve at the affected side was not correlated with the duration of time since stroke (r ≤ 0.3, p ≥ 0.05).Conclusions: These results suggest that chronic flexed wrist posture may cause atrophy of the median nerve due to chronic compression after stroke and increase in the stiffness of the median nerve.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Aslan

Analan

2018

Med Ultrason

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“…22 , 24 - 26) Therefore, the irregular shape of the median nerve is influenced by compression stress from surrounding finger flexor tendons within the carpal tunnel. The changes in the MNCSA in the typing I and typing II conditions may suggest an observable proportionate change in the median nerve diameter over typing time.…”

Section: Discussionmentioning

confidence: 99%

Impact of keyboard typing on the morphological changes of the median nerve

Loh

Yeoh

Nakashima

et al. 2017

Journal of Occupational Health

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Objectives: The primary objective was to investigate the effects of continuous typing on median nerve changes at the carpal tunnel region at two different keyboard slopes (0° and 20°). The secondary objective was to investigate the differences in wrist kinematics and the changes in wrist anthropometric measurements when typing at the two different keyboard slopes. Methods: Fifteen healthy right-handed young men were recruited. A randomized sequence of the conditions (control, typing I, and typing II) was assigned to each participant. Wrist anthropometric measurements, wrist kinematics data collection and ultrasound examination to the median nerve was performed at designated time block. Results: Typing activity and time block do not cause significant changes to the wrist anthropometric measurements. The wrist measurements remained similar across all the time blocks in the three conditions. Subsequently, the wrist extensions and ulnar deviations were significantly higher in both the typing I and typing II conditions than in the control condition for both wrists (p<0.05). Additionally, the median nerve cross-sectional area (MNCSA) significantly increased in both the typing I and typing II conditions after the typing task than before the typing task. The MNCSA significantly decreased in the recovery phase after the typing task. Conclusions: This study demonstrated the immediate changes in the median nerve after continuous keyboard typing. Changes in the median nerve were greater during typing using a keyboard tilted at 20° than during typing using a keyboard tilted at 0°. The main findings suggest wrist posture near to neutral position caused lower changes of the median nerve.

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“…Wrist angle changes are known to cause compression stress on the median nerve and lead to deformation of the median nerve at the carpal tunnel region (Loh & Muraki, 2014;Wang et al, 2014). In addition, finger movement also causes deformation of the median nerve, due to the compression from the surrounding soft tissues and the finger flexor tendon (Korstanje et al, 2010;Kursa et al, 2006;Loh et al, 2016a;Loh et al, 2016b;Ugbolue et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

D6-2　The Effect of Keyboard Typing on the Median Nerve at the Proximal Carpal Tunnel

Loh

Yeoh

Muraki

2017

The Japanese journal of ergonomics

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The aim of this study was to investigate the changes in the median nerve cross-sectional area (MNCSA) before and after keyboard typing activity. Eight right-handed healthy male adults were recruited. The participants were required to rest for 30 minutes and then perform two 30-minute typing activities on a height-adjusted table and chair. The median nerve was examined by using the GE Healthcare Ultrasound System (Model LOGIQ e) at the proximal carpal tunnel level. The ultrasound examination was performed prior to resting, before typing and at the end of each typing session. Subsequently, using a tracing method on ImageJ, the MNCSA was quantified. The MNCSAs prior to resting, before typing, after 30-minutes of typing and after 60-minutes of typing were 9.6 ± 1.7 mm 2 , 9.4 ± 1.8 mm 2 , 10.7 ± 1.9 mm 2 , and 10.2 ± 1.2 mm 2 , respectively. The main effect of typing activity on changes to the MNCSA was significant (p < 0.05) as indicated by a one-way repeated ANOVA. This study demonstrated that the median nerve became larger after 30-minutes and 60-minutes of typing activity. Biomechanical factors, such as wrist-finger movements during typing activity, and typing duration could contribute to the acute swelling of the median nerve at the proximal carpal tunnel level.

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Effect of Wrist Angle on Median Nerve Appearance at the Proximal Carpal Tunnel

Cited by 32 publications

References 42 publications

Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Impact of keyboard typing on the morphological changes of the median nerve

D6-2　The Effect of Keyboard Typing on the Median Nerve at the Proximal Carpal Tunnel

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Effect of Wrist Angle on Median Nerve Appearance at the Proximal Carpal Tunnel

Cited by 32 publications

References 42 publications

Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Effects of chronic flexed wrist posture on the elasticity and crosssectional area of the median nerve at the carpal tunnel among chronic stroke patients

Impact of keyboard typing on the morphological changes of the median nerve

D6-2 The Effect of Keyboard Typing on the Median Nerve at the Proximal Carpal Tunnel

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D6-2　The Effect of Keyboard Typing on the Median Nerve at the Proximal Carpal Tunnel