More common
in cervical spine associated with brachial plexus avulsion injury.

Rarely
occurs in lumbosacral area as a result of massive trauma such as pelvic ring
fracture or spine fracture.

Mechanism:  When
the traction force occurs..

1. Tearing
   of meninges.


2.  Nerve root avulsion.


3.  Proximal nerve root stumps retract


4.  CSF fills the neural foramina and
   adjacent tissue.

Radiologic findings:

CT myelogram : contrast-filled
nerve root sleeves containing no nerve roots.

MRI: 
Nerve roots are not visualized in neural foramen, replaced by cysts in
affected neural foramens and spinal canals. Retracted nerve stumps can be seen
outside of neural foramens.

Nerve
root injury in the lumbar spine dose not correlate with the dural injury
because nerve root avulsion can occur without forming pseudomeningocele.

Difference of post-traumatic
pseudomeningocele in lumbosacral area from  cervical area.

—  Discrepancy between the clinical
distribution of neurologic findings and the level of nerve root avulsion.

—  Partial or complete nerve root
continuity maybe present.

—  Gradual recovery of neurologic
symptom is possible.

Because there is considerable movement of lumbar cord before the root tear.

Clinical symptoms:

—  Neurologic deficits.

—  Postural headache : Intracranial
hypotension.

—  Palpable mass at the back area.

Treatment

—  Early exploratory laminectomy is not
useful !

—  Observation, conservative
treatment.

—  Surgical repairment can be
considered..

—  Remains substantial symptoms.

—  Growing  pseudomeningocele.

Reference

The Spine Journal 9(2009) e5-e10 : Traumatic
lumbosacral pseudomeningocele associated with spinal fracture.

AJNR 27 Oct 2006 1944-1946 : Lumbosacral
nerve root avulsion: MR Imaging demonstration of acute abnormalities.