Diagnostic potential of ultrasound in carpal tunnel syndrome with different etiologies: correlation of sonographic median nerve measures with electrodiagnostic severity

Basant Elnady,Ahmed El Tantawi,Sabry M Fathy,David Bong,Elsayed M Rageh,Mohammed Attar,Mohammed M Algethami,Mohamed Alshaar,El Saeed Fouda,Tohamy Ekhouly,Ahmed M Abdelaal

doi:10.1186/s12891-019-3010-5

Abstract

BackgroundCarpal tunnel syndrome (CTS) is the commonest entrapment neuropathy. The aim of this study was to assess the accuracy and validity of high resolution musculoskeletal ultrasound (US) in the diagnosis of CTS in the Saudi population.MethodsSixty patients were diagnosed clinically to have CTS involving 89 wrists that were confirmed by neurophysiologic studies. Each affected wrist was characterized as idiopathic or associated with either diabetes mellitus or hypothyroidism and were assigned a severity grade based on results of neurophysiologic studies. Seventy-six healthy wrists from fifty age, sex and BMI matched healthy subjects were included in the control group. High resolution ultrasound (US) was performed to assess median nerve cross sectional area distal (CSAd) at the entry to the carpal tunnel and proximally (CSAp) at the level of pronator quadratus muscle with a further calculation of their difference (ΔCSA) and their mean average or CSAd+CSAp/2 (CSApd).ResultsThere was a significant difference between both groups regarding mean ± SD of CSAd, CSAp, ∆CSA, and CSApd (p = 0.0001). A positive significant correlation was also found between the CSAd, ∆ CSA and the CSApd measurements with neurophysiologic severity grade of CTS (P = 0.001). A ∆CSA threshold of 2.5 mm2 showed the highest sensitivity and specificity to diagnose CTS in Saudis.ConclusionHigh resolution ultrasound is a valid and accurate diagnostic modality in carpal tunnel syndrome and correlated to CTS severity. A ∆CSA greater than 2.5 mm2 is considered a valid diagnostic value for CTS in our Saudi population. CTS in our patients with diabetes tend to have greater median nerve US measurement values.

Highlights

Carpal tunnel syndrome (CTS) is the commonest entrapment neuropathy
The aim of this study was to assess the accuracy of ultrasound in diagnosis of CTS in the Saudi population using the method developed by Klauser et al (i.e. Cross sectional area difference (ΔCSA)) and the mean of the proximal and distal measurements
A positive significant correlation was found between the Cross sectional area distal (CSAd), Δ cross-sectional area (CSA) and mean of CSApd measurements with the severity grade based on the neurophysiologic studies (P = 0.001) (Table 2)

Summary

Introduction

Carpal tunnel syndrome (CTS) is the commonest entrapment neuropathy. The aim of this study was to assess the accuracy and validity of high resolution musculoskeletal ultrasound (US) in the diagnosis of CTS in the Saudi population. Carpal tunnel syndrome (CTS) is the most frequent nerve entrapment neuropathy; it occurs secondary to compression of the median nerve under the flexor retinaculum of wrist joint and leads to an enlargement of its CTS is considered an idiopathic condition, characteristic anatomical variations may participate in development of CTS, such as persistent median artery, or a bifid median nerve (2). It may result from traumatic injury, inflammatory arthritis such as rheumatoid arthritis, or in association of hypothyroidism, diabetes mellitus, or pregnancy (3, 4). Studies had investigated median nerve CSA at the wrist in CTS patients exclusively with diabetes and hypothyroidism (17–19), a comparison of different US parameters, especially the CSA, in patients with idiopathic CTS versus those with CTS associated with diabetes and hypothyroidism has not been compared in the same study

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