Ultraschall Med 2022; 43(02): 186-193
DOI: 10.1055/a-1140-5717
Original Article

Median Nerve Injury in Ultrasound-Guided Hydrodissection and Corticosteroid Injections for Carpal Tunnel Syndrome

Schädigung des N. medianus bei ultraschallgesteuerter Hydrodissektion und Kortikosteroid-Injektionen bei Karpaltunnelsyndrom
Yi-Chih Hsu
1   Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Fu-Chi Yang
2   Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Hsian-He Hsu
1   Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
Guo-Shu Huang
1   Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
3   Medical Research, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
› Author Affiliations


Purpose Permanent nerve damage after corticosteroid injection has been suggested when symptoms of median nerve injury (MNI) are irreversible. We assess the outcomes of MNI and their association with ultrasonography (US)-guided hydrodissection and the following corticosteroid injection for symptomatic carpal tunnel syndrome (CTS).

Methods US-guided hydrodissection and the following corticosteroid injections were administered to 126 CTS patients. Occurrence of MNI, clinical data, and post-hydrodissection findings were evaluated. Post-hydrodissection findings included vascular injury during hydrodissection, altered echogenicity, reduced flattening ratio, and increased cross-sectional area of the MN at the inlet of the carpal tunnel (MN-CSA-Inlet) on ultrasonography after hydrodissection. The relevance of MNI with respect to these clinical data and findings was determined. The outcome was rated using Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) scores.

Results Nine patients suffered MNI (incidence, 7.1 %) but improved significantly at follow-up. Clinical data and vascular injury during hydrodissection, altered echogenicity, and reduced flattening ratio after hydrodissection were unrelated to prolonged transient MNI (p > 0.05). MNI was significantly associated with increased CSA (p = 0.005). A CSA increase > 2 mm2 after hydrodissection yielded the greatest performance (0.979) for MNI in the receiver operating characteristic analysis. Decreases in BCTQ scores after injection did not differ significantly between groups with and without MNI (p > 0.05).

Conclusion MNI during hydrodissection may be reversible. MNI is indicated by an increase in MN-CSA-inlet immediately after hydrodissection.


Ziel Eine permanente Nervenschädigung nach Kortikosteroid-Injektion wird angenommen, wenn die Symptome der N.-medianus-Schädigung (MNI) irreversibel sind. Wir beurteilten den Outcome der MNI und dessen Zusammenhang mit der ultraschallgesteuerten Hydrodissektion (US) und anschließenden Kortikosteroid-Injektion bei symptomatischem Karpaltunnelsyndrom (CTS).

Methoden Bei 126 CTS-Patienten wurde eine US-gestützte Hydrodissektion mit darauffolgender Kortikosteroid-Injektion durchgeführt. Das Auftreten von MNI, die klinischen Daten und die Befunde nach der Hydrodissektion wurden ausgewertet. Zu den Post-Hydrodissektionsbefunden gehörten eine Gefäßverletzung während der Hydrodissektion, eine veränderte Echogenität, ein verringerter Abflachungsquotient (flattening ratio) und eine Zunahme der Nervenquerschnittsfläche am Eingang des Karpaltunnels (MN-CSA-Inlet) in der Sonografie nach Hydrodissektion. Die Bedeutung der MNI in Bezug auf diese klinischen Daten und Befunde wurde ermittelt. Der Outcome wurde mittels „Boston-Carpal-Tunnel-Syndrome-Questionnaire“ (BCTQ) beurteilt.

Ergebnisse 9 Patienten litten an MNI (Inzidenz 7,1 %), zeigten jedoch bei der Nachuntersuchung eine signifikante Verbesserung. Die klinischen Daten und die Gefäßverletzung während der Hydrodissektion, die veränderte Echogenität und der verringerte Abflachungsquotient nach der Hydrodissektion standen nicht in Zusammenhang mit einer länger anhaltenden transienten MNI (p > 0,05). MNI war signifikant mit zunehmender CSA assoziiert (p = 0,005). Eine CSA-Zunahme > 2mm² nach Hydrodissektion erbrachte in der ROC-Analyse die beste diagnostische Leistungsfähigkeit (0,979) für MNI. Der Abfall der BCTQ-Scores nach der Injektion unterschied sich nicht signifikant zwischen den Gruppen mit und ohne MNI (p > 0,05).

Schlussfolgerung Die MNI während der Hydrodissektion ist möglicherweise reversibel. MNI wird durch eine Zunahme des MN-CSA-Inlets direkt nach der Hydrodissektion angezeigt.

Publication History

Received: 19 September 2018

Accepted: 23 February 2020

Article published online:
30 June 2020

© 2020. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany

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