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 pre ganglionic nerve rootlet avulsion from postganglionic lesions. The pur pose of this study was to evaluate the efficacy of thin-section high-r esolution CT myelography for revealing cervicothoracic nerve rootlet a vulsion in patients with brachial plexus injuries before surgery. MATE RIALS AND METHODS, We evaluated eight patients with posttraumatic or b irth-related brachial plexus injury on cervical plain film myelography and high-resolution CT myelography before surgical exploration and re pair. CT myelograms were retrospectively evaluated for nerve rootlet a vulsion, traumatic pseudomeningocele, and deformity of the subarachnoi d space. Results were correlated with surgical exploration and intraop erative somatosensory evoked potentials. RESULTS, Seventy-two (95%) of 76 imaged cervicothoracic levels were adequately shown on CT myelogra phy. Nerve rootlet avulsion, or preganglionic disruption, was shown at 21 levels. Associated pseudomeningocele, or deformity of the subarach noid space, was seen at 12 (57%) of the 21 avulsion levels. Surgical e xploration and intraoperative somatosensory evoked potentials showed c omplete 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 o n CT myelography (95% sensitivity, 98% specificity). At surgery, parti al nerve rootlet avulsion was found at three other levels. None of the partial avulsions was correctly identified on the CT myelograms. CONC LUSION, High-resolution CT myelography with thin contiguous axial sect ions is sensitive for revealing complete nerve rootlet avulsion in pat ients with brachial plexus birth palsies and brachial plexus injuries after trauma. Preoperative CT myelography in these patients allows a m ore complete injury evaluation for accurate prognosis and surgical pla nning.