Abstract
The relative importance and use of motor evaluation to diagnose carpal tunnel syndrome
(CTS) is not clear. Because the ulnar nerve is not affected in CTS, we evaluated comparing
the strength of the median-nerve innervated muscles to the ulnar innervated muscles
in the same patient, through manual muscle testing (MMT) and a handheld dynamometer.
Our purpose was to evaluate whether this method, which takes into account patient-dependent
factors that would affect both groups of muscles equally, can provide better assessment
of CTS. A retrospective case-control review of MMT and dynamometer-measured strength
for CTS was performed. The study was performed retrospectively but prior to surgery
or other treatment. There were 28 cases (CTS) and 14 controls (without CTS). Positive
nerve conduction tests defined cases. MMT of the thenar musculature was found to be
unreliable as a test for CTS. Comparisons to ulnar nerve innervated muscle strength
did not improve sensitivity or specificity of the MMT examination. Use of the dynamometer
improved sensitivity and specificity of motor testing in CTS over MMT. Motor evaluation
is important for the diagnosis of CTS, but further study is warranted, specifically
to define the method of motor evaluation and delineate the subgroup of patients (predominantly
thenar motor presentation) that would benefit most from motor testing and motor-focused
treatment.
Keywords
carpal tunnel syndrome - diagnosis - dynamometer - motor examination - ulnar
