Musculoskeletal and Emergency ImagingVascular compromise in a torsed transposed ulnar nerve case in support of intravenous contrast administration
Introduction
Torsion of peripheral nerves has been identified in patients with mono-neuropathies as well as in patients with a diagnosis of neuralgic amyotrophy. Focal scarring and adhesions as well as abnormal motion have been suggested as part of the underlying mechanism for nerve torsion [1,2]. Nerve torsion may involve multiple nerves, a single nerve, multiple nerve fascicles or a single nerve fascicle. It may involve a short nerve segment of the nerve with or without focal “hourglass” nerve constriction or it may present as twisting of a long nerve segment [1,3]. When identified, nerve torsion is treated surgically [1]. Peripheral nerves are relatively protected from ischemia due to the redundant vascular supply [4]. If present, vascular compromise and ischemia may impact the surgical treatment, with some cases requiring resection and nerve suture [2].
We present a case of long segment torsion with associated vascular compromise of the ulnar nerve following anterior subcutaneous transposition. To our knowledge, the imaging appearance of torsion with vascular compromise following anterior subcutaneous transposition has yet to be described. Preoperative imaging diagnosis of nerve torsion and vascular compromise will impact preoperative consent and treatment.
Section snippets
Clinical presentation
A 54-year-old man with no significant past medical history presented for evaluation of a suspected left ulnar neuropathy. The patient had a history of fall on the left elbow with olecranon fracture 35 years prior. He underwent subcutaneous ulnar nerve transposition at that time. He noticed improvement in his symptoms after surgery, but mild weakness and parasthesiae remained. Over the two years prior to presentation, his sensory symptoms and hand weakness worsened significantly.
On examination,
Discussion
Nerve fascicles are surrounded by the perineurium. The perineurial layer form a blood nerve barrier (BNB) through desmosomes and tight junctions as well as through the endothelial tight junctions of the intrafascicular capillaries (Fig. 5). The epineurial surface of peripheral nerves has a rich vascular blood supply including a plexus of arterioles, venules and arteriovenous shunt with arterial branches penetrating the endoneurium at regular intervals. This network affords relative protection
Conclusions
This is the first imaging description of torsion and vascular compromise of an ulnar nerve following anterior subcutaneous transposition with distinct imaging findings on US and MRI. The radiologist should be actively seeking out these complications as transposed ulnar nerves may be more vulnerable to torsion and to vascular compromise following torsion. Intravenous contrast administration should be considered to assess for vascular compromise of the nerve. The correct imaging diagnosis will
CRediT authorship contribution statement
Yoav Morag: Conceptualization, Writing original draft, Writing - Review & Editing.
David Altshuler: Writing original draft, Writing - Review & Editing.
Kara Udager: Writing - Review & Editing.
Lynda C. Yang: Conceptualization, Writing original draft, Writing - Review & Editing.
Declaration of competing interest
The authors declare that they have no conflict of interest.
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