Abstract
We explored the contribution of median nerve small (Aδ, C)-and large (Aβ)-fiber damage
to the severity and topographic distribution of sensory symptoms in carpal tunnel
syndrome (CTS) and the timing of fiber damage across CTS stages. We recruited 106
CTS patients. After selection, 49 patients were included. They underwent electrodiagnostic
and quantitative sensory testing (QST) study and were asked on the severity of Boston
Carpal Tunnel Questionnaire (BCTQ) Symptoms Severity Scale, daytime pain (DP), night
pain and paresthesia, on the distribution of hand symptoms, and the presence of proximal
symptoms. BCTQ Symptoms Severity Scale and DP severity was significantly correlated
with Aδ-fiber damage. Small-fiber QST measures were impaired in electrodiagnostic-negative
CTS patients and did not change across CTS neurographic stages. QST findings were
not correlated to the topographical distribution of symptoms. Aδ-fiber damage contributes
to CTS symptoms and in particular to DP. Night pain and paresthesia might be ascribed
to ectopic fiber discharges secondary to median nerve enhanced mechanosensitivity.
Small-fiber damage takes place earlier than large fiber. Median nerve fiber involvement
does not directly contribute to extraterritorial symptoms spread. Our data may help
understanding CTS pathophysiology and explain the well-known discrepancy between CTS
symptoms and electrodiagnostic findings.
Perspective
We explored the involvement of median nerve small and large fibers in carpal tunnel
syndrome (CTS). We found a significant correlation between Aδ-fiber function and CTS
symptoms. Small-fiber involvement took place in milder disease stages. These findings
could help reconcile the discrepancy between CTS symptoms and electrodiagnostic data.
Key words
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Article info
Publication history
Published online: August 27, 2010
Accepted:
June 25,
2010
Received in revised form:
May 31,
2010
Received:
April 6,
2010
Identification
Copyright
© 2011 American Pain Society. Published by Elsevier Inc. All rights reserved.
