Imaging of Idiopathic Spinal Cord Herniation

Abstract

Idiopathic spinal cord herniation, unlike spinal cord herniation with a known traumatic or postoperative origin, is a relatively rare condition; however, it has been diagnosed and reported with increasing frequency in recent years. Such herniation most often occurs in the thoracic spine, between the T4 and T7 vertebrae. Brown-Séquard syndrome is the most frequently reported clinical feature. Early manifestations may include numbness and decreased temperature sensation in the legs, gait disturbances, pain, and incontinence. Symptoms often worsen over time, but timely diagnosis and treatment may allow the reversal of neurologic deficits. Surgical reduction typically is performed in patients with a history of symptom progression, but patients whose symptoms are less severe may be eligible for less invasive therapy and monitoring. Imaging features of spinal cord herniation generally include a dural tear through which a portion of the cord protrudes. Cerebrospinal fluid flows freely through the defect, causing increased turbulence in the fluid just dorsal to the site of herniation. The observation of this feature may allow the differentiation of spinal cord herniation from an arachnoid cyst. In addition, the calcification of nucleus pulposus leakage from a herniated disk may produce a linear area of hyperattenuation at computed tomography or signal hyperintensity at magnetic resonance imaging, an imaging feature known as the "nuclear trail" sign.

The thoracic anterior spinal cord adhesion syndrome

“…Several cases presented with less typical constellations of symptoms, including bilateral lower limb motor weakness, myoclonic episodes and focal position-related radicular pain. This correlates with previously documented clinical manifestations of similar cohorts [7].…”

“…In a relevant recent review on imaging of this condition [7], MRI was considered sufficient for the diagnosis of cord herniation in most cases, with myelography and CT assessment for clarification in equivocal cases. In our local experience we have found that the routine use of three-dimensional volume T 2 * sequences (such as CISS) in these cases provide high-resolution images which aid the surgical decision-making process while limiting the need for an invasive procedure.…”

The Value of Additional Cervicothoracic Spine Sagittal T2-weighted Images Included in Routine Lumbar Spine MR Imaging

“…In this study, idiopathic spinal cord herniation was found on CT SAG T2WIs in two patients. Idiopathic spinal cord herniation is also known as spontaneous transdural spinal cord herniation and is a rare cause of thoracic myelopathy (10)(11)(12). However, it has been reported with increasing frequency in recent years (10).…”

Postoperative MR Imaging of Spontaneous Transdural Spinal Cord Herniation: Expected Findings and Complications

“…Clinical findings are nonspecific, and patients are typically affected by a slowly progressive, Brown-Séquard syndrome or paraparesis. 2 A variety of theories have been postulated to explain the pathogenesis of this entity, but the exact cause of dural defects remains unclear. 1 Surgical treatment to restore a herniated cord to its normal intradural position is mandatory for maximum reversal of neurologic deficits.…”

“…These increases may be due to a growing awareness among clinicians and radiologists and to improvements in MR imaging quality. [2][3][4] A well-defined set of MR imaging diagnostic criteria has been established for STSCH 2,[4][5][6] ; however, little has been said about postoperative MR imaging of changes in the spinal cord and adjacent structures. Less than half of the cases reported in the literature have described postoperative MR imaging features after reduction of spinal cord herniation 1,4,[7][8][9][10] ; none provided descriptions of a rational analysis; and in cases of complications, few have performed time-related assessments of the findings.…”