Detection of nerve rootlet avulsion on CT myelography in patients with birth palsy and brachial plexus injury after trauma.

OBJECTIVE

Recent advances in neurosurgical treatment of traumatic and birth-related brachial plexus injuries require differentiation of preganglionic nerve rootlet avulsion from postganglionic lesions. The purpose of this study was to evaluate the efficacy of thin-section high-resolution CT myelography for revealing cervicothoracic nerve rootlet avulsion in patients with brachial plexus injuries before surgery.

MATERIALS AND METHODS

We evaluated eight patients with posttraumatic or birth-related brachial plexus injury on cervical plain film myelography and high-resolution CT myelography before surgical exploration and repair. CT myelograms were retrospectively evaluated for nerve rootlet avulsion, traumatic pseudomeningocele, and deformity of the subarachnoid space. Results were correlated with surgical exploration and intraoperative somatosensory evoked potentials.

RESULTS

Seventy-two (95%) of 76 imaged cervicothoracic levels were adequately shown on CT myelography. Nerve rootlet avulsion, or preganglionic disruption, was shown at 21 levels. Associated pseudomeningocele, or deformity of the subarachnoid space, was seen at 12 (57%) of the 21 avulsion levels. Surgical exploration and intraoperative somatosensory evoked potentials showed complete preganglionic nerve rootlet avulsion at 22 levels. One of the complete avulsions revealed by surgery was not included on the patient's CT myelogram. Of the 21 imaged levels, 20 were correctly revealed on CT myelography (95% sensitivity, 98% specificity). At surgery, partial nerve rootlet avulsion was found at three other levels. None of the partial avulsions was correctly identified on the CT myelograms.

CONCLUSIONS

High-resolution CT myelography with thin contiguous axial section is sensitive for revealing complete nerve rootlet avulsion in patients with brachial plexus birth palsies and brachial plexus injuries after trauma. Preoperative CT myelography in these patients allows a more complete injury evaluation for accurate prognosis and surgical planning.