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Vasomotor dysfunction in carpal tunnel syndrome.
Einar P V Wilder-Smith1, Stephanie Fook-Chong, Soh Eng Chew
1Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore. mdcwse@nus.edu.sg
Muscle & Nerve
|October 23, 2003
Summary
Small-fiber dysfunction, indicated by impaired vasomotor function, is common in carpal tunnel syndrome (CTS). This study found reduced vasoconstriction in CTS patients, suggesting a role for small nerve fibers in the condition.
Area of Science:
- Neuroscience
- Vascular Biology
- Clinical Medicine
Background:
- Carpal tunnel syndrome (CTS) is primarily associated with large nerve fiber dysfunction.
- Small nerve fibers, responsible for vasomotor control, are often overlooked in CTS.
- Symptoms related to small-fiber dysfunction are frequently observed in CTS patients.
Purpose of the Study:
- To investigate the presence and extent of vasomotor dysfunction in patients diagnosed with carpal tunnel syndrome.
- To compare small nerve fiber-mediated vasomotor function between CTS patients and healthy controls.
- To assess the diagnostic utility of measuring vasoconstriction for identifying CTS.
Main Methods:
- Utilized laser Doppler velocimetry to quantify skin vasoconstriction.
- Applied eutectic mixture of local anesthetic (EMLA) cream to digit tips (3, 4, and 5) to induce vasoconstriction.
- Compared vasomotor responses in hands with CTS (n=32) against healthy controls (n=19).
Main Results:
- Patients with CTS exhibited significantly reduced vasoconstriction in digit tips 3 and 4 compared to controls.
- No significant difference in vasoconstriction was observed in digit tip 5 between groups.
- A blood flow ratio (digit 3/5) below 0.73 showed 69% sensitivity and 68% specificity for detecting CTS.
Conclusions:
- Small-fiber mediated vasomotor dysfunction is present in carpal tunnel syndrome.
- This dysfunction is quantifiable using laser Doppler velocimetry and EMLA cream.
- Incorporating vasomotor function testing can enhance comprehensive neurophysiological evaluations for CTS, complementing large nerve fiber assessments.