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Original Article

The Korean Journal of Pain 2020; 33(1): 54-59

Published online January 1, 2020 https://doi.org/10.3344/kjp.2020.33.1.54

Copyright © The Korean Pain Society.

The prognostic value of median nerve thickness in diagnosing carpal tunnel syndrome using magnetic resonance imaging: a pilot study

Sooho Lee1,* , Hyung Rae Cho2,* , Jun Sung Yoo2 , and Young Uk Kim3

1Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
2Department of Anesthesiology and Pain Medicine, Myongji Hospital, Hanyang University College of Medicine, Goyang, Korea
3Department of Anesthesiology and Pain Medicine, Catholic Kwandong University International St. Mary’s Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea

Correspondence to:Young Uk Kim
Department of Anesthesiology and Pain Medicine, Catholic Kwandong University International St. Mary’s Hospital, Catholic Kwandong University College of Medicine, 25 Simgok-ro 100beon-gil, Seo-gu, Incheon 22711, Korea
Tel: +82-32-290-3570
Fax: +82-32-290-3568
E-mail: uk201@hanmail.net

*These authors contributed equally to this work.

Received: July 16, 2019; Revised: September 16, 2019; Accepted: September 16, 2019

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

The median nerve cross-sectional area (MNCSA) is a useful morphological parameter for the evaluation of carpal tunnel syndrome (CTS). However, there have been limited studies investigating the anatomical basis of median nerve flattening. Thus, to evaluate the connection between median nerve flattening and CTS, we carried out a measurement of the median nerve thickness (MNT).

Methods

Both MNCSA and MNT measurement tools were collected from 20 patients with CTS, and from 20 control individuals who underwent carpal tunnel magnetic resonance imaging (CTMRI). We measured the MNCSA and MNT at the level of the hook of hamate on CTMRI. The MNCSA was measured on the transverse angled sections through the whole area. The MNT was measured based on the most compressed MNT.

Results

The mean MNCSA was 9.01 ± 1.94 mm2 in the control group and 6.58 ± 1.75 mm2 in the CTS group. The mean MNT was 2.18 ± 0.39 mm in the control group and 1.43 ± 0.28 mm in the CTS group. Receiver operating characteristics curve analysis demonstrated that the optimal cut-off value for the MNCSA was 7.72 mm2, with 75.0% sensitivity, 75.0% specificity, and an area under the curve (AUC) of 0.82 (95% confidence interval [CI], 0.69–0.95). The best cut off-threshold of the MNT was 1.76 mm, with 85% sensitivity, 85% specificity, and an AUC of 0.94 (95% CI, 0.87–1.00).

Conclusions

Even though both MNCSA and MNT were significantly associated with CTS, MNT was identified as a more suitable measurement parameter.

Keywords: Anatomy, Area Under Curve, Carpal Tunnel Syndrome, Diagnosis, Hamate Bone, Magnetic Resonance Imaging, Median Nerve, ROC Curve, Wrist