Feasibility and efficacy of transcranial motor-evoked potential monitoring in neuroendovascular surgery.

BACKGROUND AND PURPOSE: Neurophysiological monitoring for neuroendovascular procedures typically involves EEG and SSEP monitoring via cutaneous electrodes. MEP monitoring has been used less frequently because, traditionally, this has required subdural electrode placement. With the advent of transcutaneous techniques, MEP monitoring use has increased. However, little has been published regarding the use of this technique in therapeutic neuroendovascular procedures. The purpose of this study was therefore to determine whether TcMEP monitoring is feasible and efficacious in therapeutic neuroendovascular procedures. MATERIALS AND METHODS: We retrospectively reviewed our data base of therapeutic neuroendovascular procedures performed with the use of TcMEP monitoring. We specifically determined the incidence of TcMEP changes compared with changes in either SSEP or EEG. We then correlated these changes to actual adverse neurologic events. RESULTS: Although TcMEP monitoring was technically successful in all of the 140 patients in which it was attempted, we observed significant changes in TcMEP signals in only 1 patient. This patient experienced changes involving all 3 monitoring modalities after intraprocedural aneurysm rupture. In contrast, changes in SSEP tracings alone were found in 9 patients. Of these, 2 patients were known to be moribund before their procedures and neither recovered. Among the remaining 7 patients, temporary SSEP changes tended to correlate with temporary neurologic deficits, while permanent changes were associated with permanent or long-lasting deficits. CONCLUSIONS: These results suggest that TcMEP monitoring is feasible in therapeutic neuroendovascular procedures. However, it appears that the addition of TcMEP monitoring provides no added benefit to SSEP and EEG monitoring alone.

Identification of trauma patients at risk of thoracic aortic tear by mechanism of injury.

OBJECTIVE: We sought to identify potential measurable on-scene information that would assist clinicians in the identification of patients at risk for thoracic aortic tear (AT) after vehicular trauma. METHODS: Data were prospectively collected at the scene of 295 motor vehicle crashes from 1995 to 1999. There were 34 cases (12%) with AT. Scene data consisted of vehicle maximal crush, maximal intrusion into the occupant compartment, change in velocity (Delta V) and principal direction of force. Thoracic aortic injuries were confirmed radiographically or at autopsy. Crash factors were analyzed for correlation with AT by logistic regression. RESULTS: Delta V > or = 20 mph and near-side impact were the factors having the strongest correlation with thoracic aortic injury. Delta V > or = 20 mph (n = 32 with AT) had an odds ratio = 6.4, (p < 0.01). Near impact (n = 20 with AT) had an odds ratio = 2.3, (p < 0.05) and intrusion > or = 15 inches had an odds ratio = 3.2, p < 0.05. The sensitivity, specificity, and accuracy of the presence of near impact, Delta V > or = 20 mph, or both, were 100%, 34%, and 64%. The positive and negative predictive values were 16% and 100%, respectively. There was no relationship of AT to use of seat belts or airbags. CONCLUSION: Thoracic aortic injury after vehicular collision can be reliably excluded if near-impact, Delta V > or = 20 mph, or intrusion > or = 15 inches are not present. Mechanism of injury in the form of crash scene information may aid clinicians in identifying individuals at risk for thoracic aortic tear after vehicular trauma.