History: 45-year-old man with phantom pain after traumatic right arm amputation
LINK (not exact case)
Findings: An oblique view from a cervical myelogram demonstrates no normal exiting nerve roots and an abnormal collection of contrast on the right at C7/T1 (I don’t have the original images). Axial postmyelogram CT and coronal reformatted images better show the right-sided C7/T1 contrast collection.
Diagnosis: Right C8 nerve root avulsion with psuedomeningocele
Discussion: Nerve root avulsions occur secondary to severe traction on the exiting nerve roots. These are seen most commonly in the cervical spine in association with traction injuries of the arm but can occurs in the lumbosacral region secondary to lumbosacral or pelvic fractures.
In medicine, an avulsion is an injury in which a body structure is forcibly detached from its normal point of insertion by either trauma or surgery (from the Latin avellere, meaning “to tear off”).
The typical appearance on myelography, CT myelography, or MRI is that of an absent exiting nerve root at the level of the neural foramen. The avulsed nerve root often reacts laterally, leaving a cerebrospinal fluid filled cavity or pseudomeningocele in the lateral aspect of the spinal canal extending into the neural foramen and occasionally extra-foraminally into the surrounding paraspinous soft tissues. Although psudomeningoceles typically fill with contrast introduced into the subarachnoid space, they can occasionally become walled off and present as extradural cystic masses. Although many nerve root avulsions occur in association with motor vehicle accidents they also occur during birth from excessive traction on the shoulder.
A pseudomeningocele is an abnormal collection of cerebrospinal fluid (CSF) that communicates with the CSF space around the brain or spinal cord.
Aunt Minnie’s Pearls
- Sever traction injuries of the arm can lead to nerve root avulsion and pseudomeningocele formation.
an opening, hole, or passage, especially in a bone.