Radicular avulsion resulting from spinal injury: assessment of diagnostic modalities

The diagnostic utility of imaging techniques in injuries to the intramedullary and subarachnoid portions of the brachial plexus, with possibly complete avulsion of one or more nerve roots from the spinal cord and extramedullary meningocoele was compared in 18 patients studied by unenhanced computed tomography (CT), cervical myelography, myelographic CT (MCT) and magnetic resonance imaging (MRI). Emphasis was placed on the lesions of the subarachnoid roots. CM was the only diagnostic modality to show avulsion of 18 nerve roots and their levels in 8 patients (100% = gold standard), and to verify 2 incomplete avulsions. MCT reliably revealed 8 of 18 (45%) and MRI 1 out of 18 (6%) avulsions. Myelography with MCT showed intact subarachnoid nerve roots in 10 additional patients. MRI and MCT (16 out of 16 = 100%) were superior to myelography (14/16 = 88%) for demonstrating 16 traumatic meningocoeles in 8 patients; follow-up MRI (6-24 months) showed no increase in their size. We recommend a subsequent CT to role out fracture to the spinal column; MRI should provide significant information concerning oedema or haemorrhage in the spinal cord. Myelography with segmental MCT is performed to differentiate pre- from post-ganglionic lesions, data which are essential for deciding whether exploration of the plexus or a motor substitution operation is indicated.