Imaging is helpful to provide some additional basic information only.
Many peripheral nerve injury patients do not require imaging, and we rarely perform these studies to directly assess specific nerve injuries now that nerve transfers are available as a superior technique over proximal long grafts.
• X-ray of the area of injury:
• A plain x-ray of the area of injury should be obtained if underlying bony injury is suspected.
• Many upper extremity and hand injury mechanisms require imaging to check for underlying bony injury or retained foreign body; this includes crush injury, falls, lacerations, etc.
• Chest X-ray:
• Co-existing rib fractures may preclude use of intercostal nerves as a later source of a donor motor neuron for nerve transfer or free functioning muscle transfer procedures.
• Inspiration and expiration views showing loss of diaphragm function may indicate phrenic nerve injury, making both phrenic nerve and ipsilateral intercostal nerve harvest (as a donor motor neuron source) contraindicated.
CT Myelogram or MRI:
• Both of these tests are useful in aiding diagnosis of nerve root avulsion injury in closed spinal cord/brachial plexus injury:
• CT Myelogram -- may need to wait at least four weeks from injury for the characteristic meningocele (that indicates nerve root avulsion) to appear.
• CT Angiogram -- very helpful with large nerve tumors.
• MRI -- can be very helpful, but experience of the radiology team can make a big difference in the false negative and positive rates regarding information on nerve root avulsion.
• This information provides both surgical management and prognostic information:
• If the nerve root is avulsed at the level of the spinal cord, there is no chance for recovery of the function innervated by those nerve roots through a non-operative regenerative process. Consider early procedures to reinnervate (e.g., nerve transfers etc.).
• The more nerve root avulsions, the more limited the treatment options might be for specific patterns of injury.