Traumatic spinal-cord herniation associated with pseudomeningocele after lower-thoracic nerve-root avulsion.

BACKGROUND: Traumatic spinal-cord herniation after nerve root avulsion is rare. We report on the first patient with spinal-cord herniation associated with pseudomeningocele in the lower conus medullaris region after nerve avulsion. CASE: This 72-year-old man presented with progressive pain in the left leg and motor weakness after two traumatic accidents. Constructive interference in steady-state (CISS) imaging showed the attachment of the spinal cord to the wall of a herniated pseudomeningocele and associated syringomyelia at the level of T12. At the time of surgery, a herniated pseudomeningocele was observed. The lateral portion of the spinal cord that had herniated into the pseudomeningocele was detached from its wall; this was followed by repair of the dural defect. A redundant nerve root was observed inside the pseudomeningocele, suggesting nerve root avulsion as the primary lesion. To facilitate cerebrospinal fluid drainage from the syringomyelia, we next performed dorsal root entry zone (DREZ)tomy to the pseudomeningocele. Postoperatively, he manifested significant clinical improvement.
CONCLUSIONS: This is the first report of spinal cord herniation after nerve root avulsion in the conus medullaris region. CISS imaging is highly useful for the demonstration of spinal cord herniation, syringomyelia and pseudomeningocele. To restore neurological function in patients with progressive symptoms, we recommend surgical treatment.