Herniation of the spinal cord

Abstract

Herniation of the spinal cord, or displacement of the cord outside the dura, is so rare that only 13 cases have been reported in the literature. The authors report a new case of spontaneous herniation of the spinal cord in a 38-year-old man who presented with lower left limb paresis and Brown-Séquard syndrome, with a T-8 sensory level. Displacement of the spinal cord was noted on computerized tomography following myelography and on magnetic resonance imaging. The herniated cord was confirmed at operation and reduced intradurally. Postoperatively, the patient showed complete neurological recovery. Based on a review of the literature, herniation of the spinal cord may be classified as spontaneous, iatrogenic, or traumatic. At cervical levels, the spinal cord has herniated into an iatrogenic pseudomeningocele located dorsally. At thoracic levels, spinal cord herniations were reported to be in a preexisting extradural arachnoid cyst located ventrally. The authors propose a pathogenesis for spinal cord herniation based on abnormal positioning of the spinal cord in the dural sleeve and the known anteroposterior movements of the cord that occur with cardiac and respiratory pulsations. The presence of a dural defect situated on the concavity of the spinal curvature is a prerequisite for this rare condition. As adhesions develop between the cord and the edges of the dural defect, cerebrospinal fluid pulsations push the cord into a preexisting cyst. The authors suggest modifying the classification by Nabors, et al., of spinal meningeal cysts to include this mechanism of spinal cord herniation. This diagnosis should also be considered in the differential diagnosis of myelopathy in the absence of a mass lesion.

Idiopathic Spinal Cord Herniation Associated With Calcified Thoracic Disc Extrusion-Case Report-

“…At the time of diagnosis, 42 of the 60 patients presented with Brown-S áequard syndrome at the thoracic level, whereas nine patients had spastic paraparesis, seven presented with unilateral sensory deficit, and one each had hemiplegia and tetraplegia. These neurological deficits appear to be ascribable to damage of the unilateral and/or bilateral funiculi including the corticospinal and/or spinothalamic tracts at the site of the spinal cord herniation, 2,7) and depend on the location of the dural defect. 7) The interval between symptom manifestation and diagnosis was 6 months to 20 years.…”

“…These neurological deficits appear to be ascribable to damage of the unilateral and/or bilateral funiculi including the corticospinal and/or spinothalamic tracts at the site of the spinal cord herniation, 2,7) and depend on the location of the dural defect. 7) The interval between symptom manifestation and diagnosis was 6 months to 20 years. 1,3) Preoperative myelography, CT myelography, and MR imaging demonstrated the defect at the apex of a thoracic kyphosis or hump of the thoracic spine corresponding to vertebral levels of T-2 through T-10.…”

“…Myelography, computed tomography (CT) myelography, and magnetic resonance (MR) imaging demonstrate this condition as ventral displacement of the spinal cord. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Only 59 cases have been reported since the first in 1974. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] This condition is associated with a ventral dural defect of unknown etiology.…”

Spinal cord herniation into pseudomeningocele after traumatic nerve root avulsion: case report and review of the literature

“…Spinal cord herniation can be classified as spontaneous, posttraumatic, and iatrogenic [6]. Idiopathic spinal cord herniation occurs exclusively in the thoracic spine, with a female/male ratio of approximately 2:1 and it usually affects middle-age patients [2,9,10,13,15]. But posttraumatic and iatrogenic spinal cord herniation remain a rare conditions with only a small number of reports in the literature [5,7,8,12,17,18].…”

“…The outcome appears to be favorable in most 3 Spinal cord herniation into a pseudomeningocele in a intraoperative view. The small arrow shows the spinal cord herniation and the large arrow shows pseudomeningocele due to nerve root avulsion surgically treated patients, however, persistent sensory symptoms are observed in some cases [9,10,14,15].…”