Ultrasonographic Assessment of Carpal Tunnel Syndrome Severity

Abstract

Objective The aim of the study was to investigate the overall estimates of cross-sectional areas of the median nerve measured by ultrasonography in accordance with the electrodiagnostic classification of carpal tunnel syndrome severity. Design MEDLINE (PubMed), Embase (Ovid), and Web of Science were searched for studies reporting the median nerve cross-sectional area measured by ultrasonography for mild, moderate, and severe carpal tunnel syndrome based on electrodiagnostic study. Cross-sectional area values measured at the carpal tunnel inlet were included in the analyses. Results Overall, 866 citations were retrieved and checked for eligibility. Finally, 16 articles were included for meta-analysis. These studies included a total sample of 2292 wrists including 776 mild, 823 moderate, and 693 severe carpal tunnel syndrome. The pooled analysis revealed a mean cross-sectional area of 11.64 mm2 (95% confidence interval = 11.23–12.05 mm2, P < 0.001) for mild carpal tunnel syndrome, a mean cross-sectional area of 13.74 mm2 (95% confidence interval = 12.59–14.89 mm2, P < 0.001) for moderate carpal tunnel syndrome, and a mean cross-sectional area of 16.80 mm2 (95% confidence interval = 14.50–19.1 mm2, P < 0.001) for severe carpal tunnel syndrome. Conclusions This is the first meta-analysis that provides the pooled median nerve cross-sectional area values in accordance with the electrodiagnostic classification of carpal tunnel syndrome severity. The values obtained in this study have clinical utility in ultrasonographic assessment of patients with carpal tunnel syndrome.

Ultrasound (US) Changes in the Median Nerve Cross‐Sectional Area After Microinvasive US‐Guided Carpal Tunnel Release

“…3,[14][15][16][17][18][19][20][21] Postoperative median nerve CSA reductions appear to be similar among patients treated with open and endoscopic CTR, and in both cases, the reduction in the median nerve CSA has been interpreted to represent a reduction in intraneural edema as a result of successful TCL transection. 3,[13][14][15][16][17][18][19][20] Despite the improvement in median nerve CSA after open and endoscopic CTR, the CSA does not necessarily return to normal even at long-term follow-up in clinically improved patients. 3,[14][15][16]20,21 The precise reason for these observations is unknown but may be reflective of permanent structural changes within the median nerve (eg, fibrosis).…”

“…The most commonly used and valid finding in patients with CTS is enlargement of the median nerve in the proximal carpal tunnel region (ie, at or proximal to the scaphoid and pisiform), typically reported as the median nerve cross‐sectional area (CSA) . For example, the US‐measured proximal median nerve CSA has similar sensitivity and specificity as electrodiagnostic testing in the diagnosis of CTS when clinical findings are used as a reference standard, and a CSA of greater than 15 mm 2 correlates with electrodiagnostically severe CTS . The observed increases in the proximal median nerve CSA are often accompanied by hypoechogenicity and a reduction in the normal fascicular architecture .…”

“…Despite potentially significant methodological differences, most of these studies reported reductions in the proximal median nerve CSA during follow‐up periods of 1 to 12 months after CTR . Postoperative median nerve CSA reductions appear to be similar among patients treated with open and endoscopic CTR, and in both cases, the reduction in the median nerve CSA has been interpreted to represent a reduction in intraneural edema as a result of successful TCL transection . Despite the improvement in median nerve CSA after open and endoscopic CTR, the CSA does not necessarily return to normal even at long‐term follow‐up in clinically improved patients .…”

“…10,11 For example, the US-measured proximal median nerve CSA has similar sensitivity and specificity as electrodiagnostic testing in the diagnosis of CTS when clinical findings are used as a reference standard, and a CSA of greater than 15 mm 2 correlates with electrodiagnostically severe CTS. [11][12][13] The observed increases in the proximal median nerve CSA are often accompanied by hypoechogenicity and a reduction in the normal fascicular architecture. 3,4,10 These changes are presumed to represent the US manifestations of intraneural edema and therefore may be at least partially reversible after successful treatment.…”

Injection Techniques for Common Chronic Pain Conditions of the Hand: A Comprehensive Review

“…Severity is dependent on the cross-sectional area of median nerve that is affected. Mild disease involves 11.64 mm 2 , moderate disease affects 13.74 mm 2 , and severe CTS involves 16.8 mm 2 [27]. Severity can additionally be determined clinically or via nerve conduction studies.…”