University of Oulu

Henri Grönfors, Sari-Leena Himanen, Lauri Martikkala, Mika Kallio, Katri Mäkelä, Median nerve ultrasound cross sectional area and wrist-to-forearm ratio in relation to carpal tunnel syndrome related axonal damage and patient age, Clinical Neurophysiology Practice, Volume 8, 2023, Pages 81-87, ISSN 2467-981X,

Median nerve ultrasound cross sectional area and wrist-to-forearm ratio in relation to carpal tunnel syndrome related axonal damage and patient age

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Author: Grönfors, Henri1; Himanen, Sari-Leena1,2; Martikkala, Lauri1;
Organizations: 1Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, 33520 Tampere, Finland
2Department of Clinical Neurophysiology, Tampere University Hospital, Medical Imaging Centre and Hospital Pharmacy, Elämänaukio 2, 33520 Tampere, Finland
3Department of Clinical Neurophysiology, Oulu University Hospital, Kajaanintie 50, 90220, PL 10, 90029 OYS, Finland
4Research Unit of Medical Imaging, Physics and Technology; University of Oulu, Kajaanintie 50, 90220; PL 10, 90029 OYS, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.5 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-08-18


Objective: Primary objective was to retrospectively examine the effects of patient age and carpal tunnel syndrome (CTS) related axon loss on median nerve (MN) high resolution ultrasound (HRUS) in younger and older patients. HRUS parameters evaluated in this study were MN cross sectional area at the wrist (CSA) and wrist-to-forearm ratio (WFR).

Methods: The material comprised 467 wrists of 329 patients. The patients were categorized into younger (<65 years) and older (≥65 years) groups. Patients with moderate to extreme CTS were included in the study. Axon loss of the MN was assessed by needle EMG and graded by the interference pattern (IP) density. The association between axon loss and CSA and WFR was studied.

Results: The older patients had smaller mean CSA and WFR values compared to the younger patients. CSA correlated positively to the CTS severity only in the younger group. However, WFR correlated positively to CTS severity in both groups. In both age groups, CSA and WFR correlated positively with IP reduction.

Conclusions: Our study complemented recent findings on the effects of patient age on the CSA of the MN. However, although the MN CSA did not correlate with the CTS severity in older patients, the CSA increased in respect to the amount of axon loss. Also, as a new result, we presented the positive association of WFR with CTS severity among older patients.

Significance: Our study supports the recently speculated need for different MN CSA and WFR cut-off values for younger and older patients in assessing the severity of CTS. With older patients, WFR may be a more reliable parameter to assess the CTS severity than the CSA. CTS related axonal damage of the MN is associated to additional nerve enlargement at the carpal tunnel intel site.

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Series: Clinical neurophysiology practice
ISSN: 2467-981X
ISSN-E: 2467-981X
ISSN-L: 2467-981X
Volume: 8
Pages: 81 - 87
DOI: 10.1016/j.cnp.2023.02.003
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
Funding: This study was financially supported by Competitive State Research Financing of the Expert Responsibility area of Tampere University Hospital (Grants 9U007, 9V005, 9AB008).
Copyright information: © 2023 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (