Protocol of neurophysiologic studies in the carpal tunnel syndrome
Background: Entrapment of the median nerve at the wrist, called also “carpal tunnel syndrome” (CTS), is the most common neuropathy. Clinically it presents as tingling in the fi rst 3½ fi ngers that are worst during the night or in the morning, and get relieved by hand shaking. To confi rm CTS nerve...
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| Format: | Article |
| Language: | English |
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Slovenian Medical Association
2009-11-01
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| Series: | Zdravniški Vestnik |
| Online Access: | http://vestnik.szd.si/index.php/ZdravVest/article/view/392 |
| Summary: | Background: Entrapment of the median
nerve at the wrist, called also “carpal tunnel
syndrome” (CTS), is the most common neuropathy.
Clinically it presents as tingling in
the fi rst 3½ fi ngers that are worst during the
night or in the morning, and get relieved by
hand shaking. To confi rm CTS nerve conduction
studies (NCS) are very useful. Th e
aim of the present study was to present and
validate standardized protocol for neurophysiologic
studies in patients with suspected
CTS.
Methods: A standard NCS protocol includes
bilateral median (pathologic latency > 4.4 ms)
and unilateral ulnar motor NCS, and 3 comparison
sensory studies of median nerve 2
with ulnar nerve (4th fi nger detection, and
across the wrist; pathologic latency diff erences
> 0.4 and > 0.3), and 1 with radial nerve
(1st fi nger detection; pathologic > 0.6 ms). In
addition, the Carpal Sensory Index (CSI) was
calculated by summation of all 3 sensory differences
(pathologic > 0.9 ms). A group of 91
patients referred for NCS by plastic surgeons
due to suspected CTS, and a group of 52 asymptomatic
controls were studied using this protocol. Sensitivity, specifi city, positive and
negative predictive values were calculated.
Results: In controls all motor, and sensory
responses were obtained. CTS was confi
rmed in 155 of 182 (85 %) hands aft er motor
and 4th fi nger sensory studies were concluded.
Calculation of CSI demonstrated CTS in
additional 11⁄15 (73 %) hands, which raised
overall sensitivity to 91 %. Specifi cities were 89 % and 82 %, positive predictive values 93 %
and 89 %, negative predictive values 73 % and
79 % for 4th fi nger sensory comparison study
and CSI, respectively.
Conclusions: Study demonstrated that most
CTS are confi rmed by 4th fi nger sensory
comparison study. Additional two comparison
studies are needed only rarely, and confi
rm CTS in about ¾ of remaining hands. |
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| ISSN: | 1318-0347 1581-0224 |