FAILURE OF SURGERY IN IDIOPATHIC SPINAL CORD HERNIATION - Case Report and Review of the Literature.

Idiopathic spinal cord herniation is a disorder in which the spinal cord herniates through a dural defect. We present a case in which both the standard surgical method and a salvage method failed.A 36 year-old man presented with two years of progressive numbness and proximal hip flexion weakness of both lower extremities. MRI of the thoracic spine was suggestive for a ventral spinal cord herniation at the T6/7 level. He was initially treated with reduction of his cord herniation, placement of a ventral sling of collagen matrix over the dural defect to prevent re-herniation, with a laminoplasty. He developed a blood-pressure-dependent paraparesis that did not recover despite a return to the OR for removal of the laminoplastic bone flap. He was again taken to the OR, the sling was removed and we enlarged the ventral dural defect rostrally and caudally to prevent strangulation of the hernia as described by Watanabe. Though in the short term he was able to recover and transfer to physical therapy, after going home he developed lower extremity weakness and low-pressure headaches. MRI showed a ventral epidural CSF pocket retropulsing the spinal cord, as well as pockets of ventral CSF collections remote from the surgery site. The patient returned to the OR and the initial surgery with the ventral sling was re-performed with resolution of the headaches and was neurologically stable and transferred to rehab. Long-term he developed left intercostal pain at the level of the surgery without radiological correlate.In this patient there was no single satisfactory surgical treatment of his ventrally herniated spinal cord - partly related to the herniated component of the cord acting as a mass within a narrow canal at the apex of the thoracic kyphosis. We encountered previously unreported complications of the ventral defect widening technique of surgical treatment.