Punched Nerve Syndrome: Ultrasonographic Appearance of Functional Vascular Nerve Impairment

Abstract

Purpose: The mechanical impact of a neighboring vessel on a “punched” nerve segment is thought to be one possible cause of compression neuropathy but has not been proven definitively. We report on 9 subjects with unclear clinical mononeuropathies in whom we could clearly define peripheral nerve impairment by such vessels on real-time high-resolution ultrasound (HRUS).

Materials and Methods: Nine subjects with unclear mononeuropathy based on clinical neurological examination were referred to our department for HRUS assessment. The shape, inner and outer echotexture, size and diameter, and overall integrity of these nerves were assessed including an exact analysis of the surrounding soft tissues to search for potentially extraneural pathology. This included duplex imaging to identify even tiny atypical vascular structures.

Results: In all patients duplex HRUS showed the pulsatile and “punching” character of the relevant vessels and the direct mechanical impact of these vessel. The involved nerve segments appeared enlarged with a hypoechoic change of echotexture including at least partial masking of their inner fascicular texture.

Conclusion: Although rare, a “punching” vessel can be the cause of a compression neuropathy. Therefore, duplex HRUS must be included in every HRUS examination of patients with otherwise unclear mononeuropathy.

Zusammenfassung

Ziel: Die mechanische Auswirkung eines benachbarten Gefäßes auf den „geschlagenen“ Nervenabschnitt sei eine mögliche Ursache für eine Kompressionsneuropathie, was jedoch bisher nie definitiv bewiesen wurde. Wir präsentieren hier 9 Patienten mit ansonsten klinisch unklaren Mononeuropathien, bei denen eine periphere Nervenschädigung durch ein derartiges Gefäß in der Echtzeit-HRUS nachgewiesen werden konnte.

Material und Methoden: 9 Patienten mit unklarer klinischer Mononeuropathie wurden für eine HRUS-Evaluierung an unsere Abteilung zugewiesen. Die Form, innere sowie äußere Echotextur, Größe und Durchmesser und die gesamte Integrität des Nervs wurden evaluiert. Zusätzlich wurden die umgebenden Weichteile inklusive Duplex-Sonografie beurteilt, um atypische Gefäße jeglicher Dimensionen darzustellen.

Ergebnisse: In allen Patienten wurde mittels Duplex-Sonografie der pulsatile Charakter eines benachbarten Gefäßes und die direkte mechanische Auswirkung dieses Gefäßes auf ein Nervensegment nachgewiesen. Das betroffene Nervensegment war durchwegs kaliberverändert mit einer hypoechogenen Echotextur und zeigte eine zumindest partielle Maskierung der inneren faszikulären Textur.

Schlussfolgerung: Obwohl selten, kann ein „schlagendes“ Gefäß die Ursache für eine Kompressionsneuropathie sein. Daher sollte die Duplex-Sonografie bei ansonsten unauffälliger HRUS-Untersuchung von Patienten mit unklarer Mononeuropathie miteingeschlossen werden.

Key words

nervous-peripheral - ultrasound - ultrasound color Doppler - ultrasound power Doppler

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