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


METHODS
Sixty 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).


RESULTS
There 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.


CONCLUSION
High 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.
['Elnady|Basant|B|http://orcid.org/0000-0002-5908-0151', 'Rageh|Elsayed M|EM|', 'Ekhouly|Tohamy|T|', 'Fathy|Sabry M|SM|', 'Alshaar|Mohamed|M|', 'Fouda|El Saeed|ES|', 'Attar|Mohammed|M|', 'Abdelaal|Ahmed M|AM|', 'El Tantawi|Ahmed|A|', 'Algethami|Mohammed M|MM|', 'Bong|David|D|']
D000328:Adult D002349:Carpal Tunnel Syndrome D016022:Case-Control Studies D004568:Electrodiagnosis D005260:Female D006801:Humans D008297:Male D008475:Median Nerve D008875:Middle Aged D009431:Neural Conduction D012680:Sensitivity and Specificity D012720:Severity of Illness Index D014463:Ultrasonography
Ultrasound Carpal tunnel syndrome Median nerve