gms | German Medical Science

Objective: Herniation of the spinal cord (myelon) through a defect in the dura is a rare but increasingly recognized condition. The underlying cause for spinal cord herniation is unclear. Several mechanisms, including minor or unrecognized trauma, congenital meningeal malformations, CSF flow pulsations, and dural erosion by dorsal arachnoid cysts, have been hypothesized as potential causes.

Method: Up to now, the largest report on spinal cord herniation [1] concluded from analysis of spinal images that discogenic dural injury might be a likely source of progressive spinal cord herniation, although no direct proof was provided. Here we describe a case of a 50-year-old female suffering from progressive myelopathy of one-year duration. During microsurgical reduction of the spinal cord herniation we identified a soft disc that penetrated the dura and arachnoid as the underlying source of the spinal cord herniation.

Results: The magnet resonance imaging findings showed a typical herniation of the spinal cord at level Th 6/7 without any further pathology. Her medical history was negative for trauma, central nervous system inflammation or spinal manipulation. The patient was referred to surgery. During microsurgical exploration of the intradural space, we identified an approximately 10 mm oval dural perforation with ventral spinal cord herniation and direct contact to a small soft disc herniation on level Th 6/7. The dura around the defect was cut with a 2 mm margin to release the trapped myelon. A dural graft matrix was gently placed anterior to the spinal cord and was fixed with fibrin glue.

Conclusions: The preoperative diagnostic work-up did not predict a disc herniation. The intraoperative microsurgical findings clearly identified a soft disc protrusion underlying the dural defect as a cause for thoracic spinal cord herniation. This case provides support for the hypothesis that tiny dura penetrating disc herniation may be a potential source of spinal cord herniation.