Understanding Idiopathic Spinal Cord Herniation – A Comprehensive Review of Imaging and Literature

Abstract

Idiopathic spinal cord herniation (ISCH) is displacement of spinal cord through a dural or arachnoidal defect. Most patients present with back pain or myelopathy, paresthesia, and sensory or motor weakness. Imaging findings include anterior displacement of the cord with possible kink, no filling defect on CT myelography, and no restricted diffusion/mass lesion on magnetic resonance imaging. Abrupt kink in the spinal cord or widened cerebrospinal fluid (CSF) space can be caused by a variety of reasons. The differential considerations include arachnoid web, intradural extramedullary epidermoid or arachnoid cyst, abscess or cystic schwannoma. We discuss the features, imaging, differentials, and treatment of ISCH as a rare cause of such kink in the cord. While reading such cases, a radiologist should include the location, segments involved, cord signal abnormality, visible defect, scalpel sign or C–sign, ventral cord kink, nuclear trail sign, the ventral CSF space preservation, or obliteration and the type.

Scalpel sign: Dorsal thoracic arachnoid web, thoracic arachnoid cyst and ventral cord herniation

“…The disorder can present at any age but most commonly between the fourth and fifth decade of life. Patients may be asymptomatic, but commonly patients present with insidious symptoms of myelopathy and a Brown-Sequard syndrome [2 , 14] .…”

Structural Myelopathies

“…46 The thoracic cord is exclusively affected. 46 The etiology of this disorder is unclear, and most patients have no history of preceding trauma or surgery. 46 Several potential mechanisms have been proposed but not proven.…”

“…46 The etiology of this disorder is unclear, and most patients have no history of preceding trauma or surgery. 46 Several potential mechanisms have been proposed but not proven. One theory suggests that remote trauma may predispose to future dural tears.…”

“…46 Clinical symptoms include numbness and decreased temperature sensation in the legs, gait disturbances, and incontinence. 46 Brown-Séquard syndrome has been seen in more than half of the reported cases. 46 MRI is the initial imaging modality of choice, but CT myelography can be very helpful and is especially recommended if the initial MRI is equivocal.…”

Neuroimaging findings and pathophysiology of dorsal spinal arachnoid webs: illustrative case

“…Although it has been suggested that symptomatic relief could be obtained by placing patients in the Trendelenburg position, 24 symptomatology is now recognized to have a progressive rather than regressive course. 44 More than 90% of patients experience rapid neurological recovery after resection, regardless of the duration of presenting symptoms. [14][15][16] FIG.…”