Ann Rehabil Med.  2016 Dec;40(6):1040-1047. 10.5535/arm.2016.40.6.1040.

Relationship Between Electrodiagnosis and Various Ultrasonographic Findings for Diagnosis of Carpal Tunnel Syndrome

• Lee KM
• Kim HJ

• KMID: 2371336
• DOI: http://doi.org/10.5535/arm.2016.40.6.1040

Abstract

OBJECTIVE
To investigate the relationship between electrodiagnosis and various ultrasonographic findings of carpal tunnel syndrome (CTS) and propose the ultrasonographic standard that has closest consistency with the electrodiagnosis.
METHODS
Ultrasonography was performed on 50 female patients (65 cases) previously diagnosed with CTS and 20 normal female volunteers (40 cases). Ultrasonography parameters were as follows: cross-sectional area (CSA) and flattening ratio (FR) of the median nerve at the levels of hamate bone, pisiform bone, and lunate bone; anteroposterior diameter (AP diameter) of the median nerve in the carpal tunnel; wrist to forearm ratio (WFR) of median nerve area at the distal wrist crease and 12 cm proximal to distal wrist crease; and compression ratio (CR) of the median nerve. Independent t-test was performed to compare the ultrasonographic findings between patient and control groups. Significant ultrasonographic findings were compared with the electrodiagnosis results and a kappa coefficient was used to determine the correlation.
RESULTS
CSA and FR of median nerve at the hamate bone level, CSA of median nerve at pisiform bone level, AP diameter of median nerve within the carpal tunnel, CSA of median nerve at the distal wrist crease and WFR showed significant differences between patient and control groups. WFR showed highest concordance with electrodiagnosis (κ=0.71, p<0.001).
CONCLUSION
These findings suggested the applicability of ultrasonography, especially WFR, as a useful adjunctive tool for diagnosis of CTS.

Keyword

Carpal tunnel syndrome; Diagnosis; Electrodiagnosis; Median nerve; Ultrasonography

MeSH Terms

Carpal Tunnel Syndrome*
Diagnosis*
Electrodiagnosis*
Female
Forearm
Hamate Bone
Humans
Lunate Bone
Median Nerve
Pisiform Bone
Ultrasonography
Volunteers
Wrist

Figure

• 

  Fig. 1 Transverse sonogram of the median nerve at three different levels in a normal subject. The cross-sectional area of the median nerve (oval dotted line). Flattening ratio was obtained by measuring transverse (a) and anteroposterior (b) diameters. (A) Hamate bone (H) level. (B) Pisiform bone (P) level. (C) Lunate bone (L) level.

• 

  Fig. 2 Longitudinal sonogram of the median nerve (between white arrows) at the level of the carpal tunnel in a normal subject. The thickest anteroposterior diameter of the median nerve (black arrow).

• 

  Fig. 3 Transverse sonogram of the median nerve with cross-sectional area (within oval dotted line) in a normal subject. (A) At the distal wrist crease. (B) At 12 cm proximal in the forearm. The wrist to forearm ratio was calculated as the ratio of the median nerve area at the distal wrist crease as compared to the forearm.

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