Symptomatic Thoracic Spinal Cord Herniation

Abstract

Background and Importance Idiopathic spinal cord herniation (ISCH) is an uncommon condition located predominantly in the thoracic spine and often associated with a remote history of a major traumatic injury. ISCH has an incompletely described presentation and unknown etiology. There is no consensus on treatment algorithm and surgical technique, and there is little data on clinical outcomes. Clinical Presentation In this case series and technical report, we describe the atypical myelopathy presentation, remote history of traumatic injury, radiographic progression, treatment, and outcomes of 5 patients treated at Washington University for symptomatic ISCH. A video showing surgical repair is presented. In contrast to classic compressive myelopathy symptomology, ISCH patients presented with an atypical myelopathy, characterized by asymmetric motor and sensory deficits and early-onset urinary incontinence. Clinical deterioration correlated with progressive spinal cord displacement and herniation observed on yearly spinal imaging in a patient imaged serially due to multiple sclerosis. Finally compared to compressive myelopathy in the thoracic spine, surgical treatment of ISH led to rapid improvement despite long duration of symptoms. Conclusion Symptomatic ISCH presents with atypical myelopathy and slow temporal progression and can be successfully managed with surgical repair.

Anterior Thoracic Spinal Cord Herniation: Surgical Treatment and Postoperative Course. An Individual Participant Data Meta-Analysis of 246 Cases

“…A total of 164 relevant articles (consisting of case reports and case series), containing a total of 338 patients with ATSCH, were identified. The selected articles were fully assessed on the patient level, which resulted in the exclusion of 104 patients as follows: 31 cases were not operated on ("conservative treatment" 8,13-27 ), 12 cases were reported twice (Ewald and Hassler cases 1 and 2) 28,29 ; Sioutos et al 30 and Henry et al 31 ; Watanabe et al 32 and Nakamura et al 33 (cases 1e9), 59 cases were excluded because of insufficient documentation (missing essential data such as level of herniation, details about surgery, clinical information preoperatively and/or postoperatively 16,20,27, ) and 2 cases were biased by conflicting spinal cord disorders (amyotrophic lateral sclerosis 44 and spinal cord injury 22 ). This selection reduced the sample of articles to 127 and the sample of patients to 234.…”

Myelopathy Due to Degenerative and Structural Spine Diseases

“…46 In this disorder, the thoracic cord (typically from T2 to T8) abuts the posterior surface of the vertebral body, resulting in a large dorsal epidural space often mistaken for an arachnoid cyst. While the clinical presentation is similar to that seen in thoracic spondylotic myelopathy with early bladder dysfunction, asymmetric weakness, and sensory deficits, a distinct imaging finding characterizes spinal cord herniation.…”

“…46 In this disorder, the thoracic cord (typically from T2 to T8) abuts the posterior surface of the vertebral body, resulting in a large dorsal epidural space often mistaken for an arachnoid cyst. 46,48 As the spinal cord ends at L1 to L2 in most individuals, spondylotic changes of the lumbar canal do not cause a true myelopathy, but may result in compression of the cauda equina or conus medullaris. 47,48 In contrast to spondylotic causes of thoracic myelopathy, surgical repair of the dural defect may restore some degree of clinical function in patients with spontaneous spinal cord herniation.…”

The Pathogenesis of Ventral Idiopathic Herniation of the Spinal Cord: A Hypothesis Based on the Review of the Literature

“…Several reviews have been published ( 1 – 3 ). Some small case series have been described ( 1 , 4 , 5 ), but most cases have been reported as single cases ( 6 – 9 ). The entity is believed to be idiopathic, as a clear cause has never been identified in the cases published.…”