BRACHIAL PLEXUS INJURY-INVESTIGATIONS

SUMMARY

1. MRI cervical spine and brachial plexus: useful to detect post-ganglionic injuries and avulsion, disc prolapse or fibrous band causing outlet syndrome.

2. Myelogram: useful to detect pre-ganglionic lesions and avulsion, disc prolapse.

3. NCS/EMG: SNAP to detect lesion distal to the DRG, CNAP to detect lesions proximal to the DRG.

4. X-ray/CT: to detect clavicle, rib, cervical fractures and shoulder dislocations and fractures or cervical rib.

PROGNOSTICATION
5. Prognosticating injury and predicting the occurrence of CRPS with NCS & EMG: particularly noting compound nerve action potential (CNAP) for prognosis & EMG as predictor for complex regional pain syndrome (CRPS).

6. SNAP & CNAP can be used to determine if the injury is distal or proximal to the DRG (poorer prognosis in preganglionic lesions).

7. The amplitude of the distal CMAP starts to drop by day 3 following the injury, and it reaches its lowest valve by day 7 [1]. Hence, the severity of the lesion can be judged after 7 days of the injury.

Reference(s)

1. Wilbourn AJ. Assessment of the Brachial Plexus and the Phrenic nerve. In: Pease WS, Johnson EW, editors. Practical Electromyography. 3rd ed. Baltimore: Williams and Wilkins; 1997. pp. 273–310.

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