The thoracic anterior spinal cord adhesion syndrome

Abstract

Objectives: This study included a series of middle-aged male and female patients who presented with chronic anterior hemicord dysfunction progressing to paraplegia. Imaging of anterior thoracic cord displacement by either a dural adhesion or a dural defect with associated cord herniation is presented. Methods: This is a retrospective review of cases referred to a tertiary neuroscience centre over a 19-year period. Imaging series were classified by two experienced neuroradiologists against several criteria and correlated with clinical examination and/ or findings at surgery. Results: 16 cases were available for full review. Nine were considered to represent adhesions (four confirmed surgically) and four to represent true herniation (three confirmed surgically). In the three remaining cases the diagnosis was radiologically uncertain. Conclusion:The authors propose ''thoracic anterior spinal cord adhesion syndrome'' as a novel term to describe this patient cohort and suggest appropriate clinicoradiological features for diagnosis. Several possible aetiologies are also suggested, with disc rupture and inflammation followed by disc resorption and dural pocket formation being a possible mechanism predisposing to herniation at the extreme end of a clinicopathological spectrum. Anterior spinal cord hernia is a rare and potentially treatable cause of progressive anterior spinal cord syndrome. The cord prolapses through an anterior or anterolateral dural defect, resulting in a progressive, frequently asymmetrical, thoracic myelopathy. Patients typically present in middle age with slowly progressive neurological dysfunction relating to anterior hemicord dysfunction [1, 2]. The condition was described in 1973 by Cobb et al [3], with the first idiopathic case suggested by Wortzman et al [4] a year later; a number of case reports and small series have been published since. The exact causative mechanism has not been fully elucidated. The radiological findings of true herniation are well described but not widely recognised as the number of cases in world literature remains relatively small.In our clinical practice we have identified a number of patients who present with a clinical picture that is indistinguishable from patients with anterior spinal cord herniation and MRI demonstration of anterior cord deviation, but without imaging or surgical evidence of a true cord hernia. Based on this observation, we suspect that true hernia is positioned at the extreme end of a pathological spectrum; other cases of anterior cord deviation and wasting-possibly caused by focal vulnerability, deficiency of the anterior dura or anterior tethering of the cord-appear to present with similar clinical symptoms. Evidence in support of this assertion is the case reported by Ewald et al [5] demonstrating progressive development of an anterolateral T6 cord herniation on successive MRI examinations, with associated progression in clinical symptoms over a 2-year period prior to operative intervention. We propose that the association of thoracic myelopat...

Focal Anterior Displacement of the Thoracic Spinal Cord without Evidence of Spinal Cord Herniation or an Intradural Mass

“…In their study, four cases showed no spinal cord herniation but did show anterior spinal cord adhesion. TASCAS with cord adhesion is conceptually different from our cases, in that Taylor et al ( 10 ) postulated spinal cord adhesion as a predisposing factor in spinal cord herniation and regarded these within one spectrum. In their study, most of the cases showed a cord abnormality adjacent to the intervertebral disc or upper margin of the disc with associated degenerative disc abnormality.…”

“…According to Taylor et al ( 10 ), thoracic anterior spinal cord adhesion syndrome (TASCAS) represents two pathologies and includes anterior cord adhesion and anterior cord herniation within a single spectrum, with cord herniation considered at one end of the spectrum. In their study, four cases showed no spinal cord herniation but did show anterior spinal cord adhesion.…”

Intradural lumbar disc herniation detected by 3D CISS MRI

“…However, several studies have demonstrated the potential of 3D high-resolution CISS to assess other intradural diseases such as redundant nerve root syndrome of the cauda equina 7 or thoracic anterior spinal cord adhesion syndrome. 8 By allowing the detection of subtle rupture of the PLL and dural defect, 9 3D high-resolution CISS should be considered also in case of suspicious IDH.…”

A Rare Case of Anterior Transdural Thoracic Spinal Cord Herniation: Magnetic Resonance Imaging Features

“…2 Idiopathic thoracic cord herniation results from a dural defect of unknown origin, and is different from herniation due to trauma or operation, which can be diagnosed by history and imaging. [5][6][7][8] It has been postulated that previous occult minor trauma or a remote traumatic event might account for the dural defect. 2 However, several authors have suggested that an underlying congenital abnormality of the dura mater (such as duplication of the dura with the cord herniating between the two layers) may be another explanation.…”

“…2 In some cases of suspected idiopathic spinal cord herniation, only focal ventral cord displacement and angulation can be observed without explicit demonstration of a segment of cord parenchyma extending outside the dura mater. 8 If the condition is sufficiently long-standing, there could be scalloping of the posterior thoracic vertebral body. 2 Phase-contrast cine MRI and conventional myelogram can demonstrate the free subarachnoid CSF movement posterior to the herniated segment and absence of filling defect in order to exclude a dorsal intradural filling defect such as that caused by an arachnoid cyst.…”