Does Ultrasonography Contribute Significantly to the Diagnosis of Carpal Tunnel Syndrome?

Abstract

Background:

Recent studies have demonstrated ultrasonography as a valuable tool for confirming the diagnosis of carpal tunnel syndrome. The objective of this study was to investigate sonographic parameters of the median nerve in patients diagnosed clinically with carpal tunnel syndrome.

Patients and Methods:

185 wrists in 185 patients, 149 women (81%) and 36 men (19%), with a mean age of 59 years, with the clinical diagnosis of carpal tunnel syndrome were examined sonographically. We measured cross-sectional area (CSA) of the median nerve at the forearm and at the carpal tunnel inlet, as well as the height (a-p dimension) of the nerve at the tunnel inlet and in the narrowest site in the carpal tunnel. Moreover, in all patients the severity of the disease was assessed by the Levine questionnaire.

Results:

A significant variability of sonographic data characterizing the median nerve was found: the mean CSA at the tunnel inlet was 17.6 mm² (range: 7–36) and height of the nerve at the tunnel inlet was a mean of 2.7 mm (range: 1.3–4.5). No correlation was found between sonographic data and severity of the syndrome as expressed by the Levine scores.

Conclusion:

Sonography of the median nerve contributes little to the diagnosis of a clinically relevant carpal tunnel syndrome and its routine use is not justified.

Zusammenfassung

Hintergrund:

Neuere Studien haben gezeigt, dass Ultraschall ein nützliches Verfahren für die Bestätigung der Diagnose des Karpaltunnelsyndroms ist. Ziel der vorliegenden Studie war, sonografische Parameter des Nervus medianus bei Patienten mit klinisch diagnostiziertem Karpaltunnelsyndrom zu ermitteln.

Patienten und Methoden:

185 Handgelenke von 185 Patienten, darunter 149 Frauen (81%) und 36 Männer (19%), mit einem mittleren Alter von 59 Jahren, mit klinisch diagnostiziertem Karpaltunnelsyndrom wurden mittels Ultraschall untersucht. Gemessen wurde die Querschnittsfläche (CSA, cross-sectional area) des Nervus medianus am Unterarm und am Karpaltunnel­eingang sowie die Dicke (a-p Dimension) des Nervs am Tunneleingang und an der engsten Stelle des Karpaltunnels. Außerdem wurde bei allen Patienten der Schweregrad der Erkrankung mit Hilfe des Levine-Fragebogens untersucht.

Ergebnisse:

Die sonografischen Befunde des N. medianus bei diagnostiziertem Karpaltunnelsyndrom zeigen eine große Streubreite: der Querschnitt am Tunneleingang betrug im ­Mittel 17,6 (7–36) mm², die Dicke des Nervs am ­Tunneleingang lag im ­Mittel bei 2,7 (1,3–4,5) mm. Es wurde keine Korrelation zwischen den sonografischen Daten und dem Schweregrad des Syndroms nach Levine-Score gefunden.

Schlussfolgerung:

Die Ultraschalluntersuchung des Nervus medianus trägt wenig zur ­Diagnose eines klinisch relevanten Karpaltunnelsyndroms bei. Der routinemäßige Einsatz ist daher nicht gerechtfertigt.

Key words

decompression - carpal tunnel syndrome - imaging procedures - expertise

Schlüsselwörter

Dekompression - Karpaltunnelsyndrom - Bildgebende Verfahren - Expertise

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