Presentation
3 months following workplace accident. Left arm vs conveyer belt.
Patient Data
There are large left epidural fluid collections consistent with pseudomeningocoeles, at C7, C8 and T1 nerve root levels consistent with preganglionic nerve root emotions. These do not extend into the extraforaminal space and their size is best demonstrated on the myelographic sequence. The spinal cord is mildly displaced to the right. More laterally, the nerve roots of the upper brachial plexus are mildly enlarged consistent with neuropraxia. The nerves of the lower brachial plexus, can be traced from just outside the foramina, and are diffusely enlarged but appear contiguous at least to the infraclavicular level. The shoulder joint is obscured by metal artefact but advanced atrophy of the pectoralis muscles and probably the deltoid is evident.
Conclusion: Preganglionic tears of the left C7 to T1 nerve roots.
Case Discussion
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.
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