Progressive Spontaneous Herniation of the Thoracic Spinal Cord: Case Report

Abstract

We present the possible causes, the proposed pathophysiological mechanisms, and the clinical and radiological development of this rare entity, with a review of the literature published to date. We propose that a preexisting weakness of the ventral dural fibers, combined with abnormal adhesion of the spinal cord to the anterior dural sleeve, leads to progressive herniation throughout life. Microsurgical treatment may halt the exacerbation of the neurological symptoms.

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

“…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. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Specifically, CT myelography and MR imaging are essential tools for the detection, visualization, and diagnosis of transdural spinal cord herniation. The characteristic findings are sharp ventral or ventrolateral displacement of the spinal cord with narrowing and deformity, and enlargement of the dorsal subarachnoid space with normal CSF flow on the sagittal and axial images.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Such dural defects have been attributed to congenital and acquired factors. Congenital defects include a hiatus in the inner layer of the duplicated dura mater, 1,12,14,15) extra-or intradural cysts or myelomeningocele, 6,9) thinning of the dura mater, 3) and weakness of ventral dural fibers.…”

“…Congenital defects include a hiatus in the inner layer of the duplicated dura mater, 1,12,14,15) extra-or intradural cysts or myelomeningocele, 6,9) thinning of the dura mater, 3) and weakness of ventral dural fibers. 4) The proposed pathogenesis of acquired defects includes damage to the dura mater by unrecognized remote spinal trauma, 1,2) vertebral body defect, 5,8,17) and thoracic disc herniation. 5,8,10) In our case, the calcified thoracic disc extrusion at the same level as the displacement of the spinal cord was identified by preoperative neuroimaging, and was confirmed to penetrate through the posterior longitudinal ligament caudal to the dural defect at surgery.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] To prevent re-herniation of the spinal cord, the dural defect must be secured by placing primary sutures, 2,7,16,17) by resection of the inner layer of the dura mater, 12,14,15) and by placing a graft patch using a surgical membrane, 3,11) muscle, 17) fascia, 2) or pericardial membrane. 3) In our patient, we performed dural plasty and filled the ventral epidural space outside the dural defect with a surgical felt sheet, and covered the herniated cord with lyophilized dura.…”

“…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.…”