In trauma, it is clinically important to differentiate between pre-ganglionic and post-ganglionic brachial plexus injuries, as prognosis varies. Preganglionic injuries are more difficult to treat and has a worse prognosis. Preganglionic lesions are proximal to the dorsal root ganglion and are typically associated with pseudomeningocoeles. They are common after nerve root avulsion but can also be present with intact nerve roots. Pseudomeningocoeles manifest as CSF collections in dural sac outpouchings due to dural/perineural tears and may contain the disrupted proximal root 1.
There are also various other signs associated with preganglionic brachial plexus injuries, including 2:
- spinal cord abnormalities: edema, hemorrhage, myelomalacia, syringomyelia, contralateral cord displacement
- spinal cord signal intensity changes in 20% of preganglionic injury patients
- T2-weighted hyperintensity of denervated paraspinal muscles (especially multifidus muscle) due to dilatation of vascular bed and enlargement of extracellular space
Case courtesy of A/Prof Pramit Phal.