Diagnosis with CTS

Two papers by the Quality Standards Subcommittee of
the American Academy of Neurology [64] and American
Association of Electrodiagnostic Medicine, American
Academy of Neurology and American Academy of Physical
Medicine and Rehabilitation define the guidelines for
clinical and neurophysiologic diagnosis of CTS [65]. These
papers stress the importance of a thorough case history,
which must focus on the following [2]:
• symptom onset - which in the early stage is mainly
nocturnal paraesthesias.
• provocative factors - such as hand positions and
repeated movements.
• working activity - instrument use, vibrating tools.
• pain localisation and irradiation - in the cutaneous
median nerve region with ascending, sometimes up to
the shoulder, or descending irradiation.
• manoeuvres which alleviate symptoms - e.g. hand
shaking, position changes.
• presence of predisposing factors - e.g. diabetes,
adiposity, chronic polyarthritis, myxoedema,
acromegaly, pregnancy.
• sports activity - e.g. baseball, body-building.
 The two provocative test most commonly used in the
clinical setting are Phalen’s and Tinel’s tests. In Phalen’s
test, the patient is asked to flex their wrist and keep it in that
position for 60 seconds. A positive response is if it leads to
pain or paraesthesia in the distribution of the median nerve
[60]. The sensitivity of Phalen’s test is in the range of 67%
to 83%, whilst the specificity ranges between 40% and 98%
[66-68].
Tinel’s test is performed by tapping over the volar surface of
the wrist. A positive response is if this causes paraesthesia in
the fingers innervated by the median nerve: the thumb,
index, middle finger and the radial side of the ring finger [6].
Tinel’s test has a sensitivity in the range of 48% to 73%,
whilst the specificity is 30% to 94% [66-68].
 It is evident that there are significant variations in these
values, which may be attributed to the fact that there are
substantial inconsistencies in the method of examination and
interpretation of the results [15]. Therefore, some researchers
have questioned their diagnostic value [69]. This, coupled
with the fact that both Phalen’s and Tinel’s tests have a low
positive predictive value, supports the view that such
provocative tests are insufficient and unreliable when used
alone in the diagnosis of CTS. This emphasises the
importance of considering them with a good clinical history
and other appropriate methods of examination, such as nerve
conduction studies (NCS) [70]. This view has recently been
supported by a study conducted by EL Miedany et al. [71].
They found that both Phalen’s and Tinel’s tests were in fact
more sensitive and specific for the diagnosis of tenosynovitis
than for the diagnosis of CTS. Therefore, they concluded
that there is a greater reliance on NCS as a diagnostic gold
standard in the diagnosis of CTS [72], despite the fact that
false positives and negatives are known to exist [34].