Measurement of the median nerve strain within the carpal tunnel using a capacitance-type strain sensor: A cadaver study. (February 2023)

• Record Type: Journal Article
• Authors: Takashima, Kenichi; Teramoto, Atsushi; Aoki, Mitsuhiro; Miyamoto, Hiroki; Hidaka, Egi; Shirato, Rikiya; Ozasa, Yasuhiro; Saito, Akira; Emori, Makoto; Yamashita, Toshihiko; Iba, Kousuke
• Is Part Of: Clinical biomechanics. Volume 102(2023)
• Publication Date: 2023-02
• Subjects: Median nerve -- Strain -- Excursion -- Quantitative evaluation -- Capacitance-type strain sensor; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2023.105894
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: Direct and quantitative measurement of median nerve strain within the carpal tunnel has been difficult because of the technical limitations associated with conventional devices. We used capacitive sensors (C-stretch), which are thin and flexible, to measure the median nerve strain within the carpal tunnel. Methods: We used 12 fresh frozen upper extremity specimens. The transverse carpal ligament was left in situ, and we attached the sensor to the palmar surface of the median nerve to measure the nerve strain at 60 degrees of wrist extension. The sensor measured the median nerve strain at both the carpal tunnel site and the proximal to the carpal tunnel site before and after the carpal tunnel release. The amount of nerve excursion during wrist extension was also measured with the length change of the attached suture by a digital caliper. Findings: The mean median nerve strain within the carpal tunnel [8.07% (95 %CI:7.17–8.97)] was significantly higher than that proximal to the carpal tunnel [5.21% (95 %CI:4.46–5.97)] at the wrist extension. There was no significant difference of the mean nerve excursion within and proximal to the carpal tunnel. The mean nerve strain and excursion were unaffected by carpal tunnel release. Interpretation: These results indicated that wrist extension position might lead to increased strain on the median nerve within the carpal tunnel compared with at the proximal to the carpal tunnel. We believe that the current study might provide new information and help us understand the pathogenesis of carpal tunnel syndrome. Highlights: A new attempt to measure the median nerve strain within the carpal tunnel using an elastic sensor. The median nerve strain within the carpal tunnel was higher than that proximal to the carpal tunnel. Nerve excursion within the carpal tunnel was not different from that proximal to the carpal tunnel. The median nerve strain and excursion were unaffected by carpal tunnel release.