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14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

17.06. - 21.06.2019, Berlin

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The structural changes of carpal tunnel and median nerve in MRI before and 2 years after endoscopic carpal tunnel release

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  • presenting/speaker Toshimitsu Momose - Department of Orthopaedics, Marunouchi Hospital, Matsumoto, Japan
  • Hiroyuki Oshiba - Department of Orthopaedics, Marunouchi Hospital, Matsumoto, Japan
  • Yukio Nakatsuchi - Department of Orthopaedics, Marunouchi Hospital, Matsumoto, Japan

International Federation of Societies for Surgery of the Hand. International Federation of Societies for Hand Therapy. 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT). Berlin, 17.-21.06.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. DocIFSSH19-544

doi: 10.3205/19ifssh0009, urn:nbn:de:0183-19ifssh00094

Published: February 6, 2020

© 2020 Momose et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

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Objectives/Interrogation: We do not know enlargement of carpal tunnel has maintained for a long time after endoscopic carpal tunnel release (ECTR). We investigated the structural changes of carpal tunnel and median nerve in MRI before and two years after ECTR.

Methods: 28 patients had undergone ECTR for idiopathic carpal tunnel syndrome. The patients included 8 males, 20 females. The mean age was 67 years old. ECTR was performed utilizing Chow's two-portal technique. MRI (Siemens, 1.5T) of carpal tunnel and nerve conduction studies (motor distal latency) was performed before and two years after ECTR. The cross-sectional area of carpal tunnel and median nerve, and palmar bowing (PB) at the hook of hamate level were measured using T2* images. The palmar bowing was the distance to the flexor retinaculum from the line between the hook of hamate and trapezium at the hook of hamate level. The cross-sectional area of median nerve was measured at wrist level. The cross-sectional area of the carpal tunnel and median nerve was outlined digitally. The expansion ratio was calculated by dividing the postoperative cross-sectional area by the preoperative cross-sectional area. Preoperative data was compared with postoperative data using Wilcoxon signed-ranks test.

Results and Conclusions: Motor distal latency was improved from 9.1 ms to 4.3 ms after ECTR. Detached flexor retinaculum was seen as a linear area of low signal intensity 2 years after ECTR. The expansion ratio of carpal tunnel and median nerve was 1.16 and 1.2 respectively at hamate level. The cross-sectional area of carpal tunnel and median nerve was significantly increased at hamate level two years after ECTR. PB was significantly increased at hamate level two years after ECTR. The expansion ratio of median nerve was 0.9 at wrist level. The cross-sectional area of median nerve was significantly decreased at wrist level two years after ECTR. The enlargement of carpal tunnel was maintained two years after ECTR. Flexor retinaculum was released during ECTR. However, a continuous linear area of flexor retinaculum was detected two years after ECTR.