Related Experiment Videos
[Intraoperative unilateral changes in myogenic motor evoked potentials in patients undergoing thoracic aortic
T Shimoda1, S Inoue, M Kakimoto
1Department of Anesthesiology, Nara Medical University, Kashihara 634-8852.
Abstract:
Motor evoked potentials (MEPs) can be employed for monitoring the functional integrity of the descending motor pathways during thoracic aortic surgery. Since MEPs can be affected by a variety of intraoperative factors, intraoperative MEP changes have to be carefully interpreted. In this report, we describe two patients undergoing thoracic aortic surgery, in whom MEPs from the unilateral lower limb disappeared after femoral artery cannulation, and MEPs' recovered by modifying the position or removing the cannula. MEPs in the contralateral side remained unchanged. Neither patients showed postoperative neurologic dysfunction in the lower limbs. These observations suggest that regional ischemia of the lower limbs caused by femoral artery cannulation can affect intraoperative MEP finding.
Insights
Intraoperative monitoring of motor evoked potentials (MEPs) during thoracic aortic surgery can be affected by femoral artery cannulation. Temporary MEP changes in lower limbs suggest regional ischemia, not necessarily neurological damage.
Area of Science:
- Neurosurgery
- Cardiovascular Surgery
- Neurophysiology
Background:
- Motor evoked potentials (MEPs) are crucial for assessing descending motor pathway integrity during thoracic aortic surgery.
- Intraoperative MEPs require careful interpretation due to potential confounding factors.
Observation:
- Two patients undergoing thoracic aortic surgery experienced unilateral lower limb MEP disappearance post-femoral artery cannulation.
- MEPs normalized upon adjusting or removing the cannula, with no contralateral changes observed.
Findings:
- Femoral artery cannulation can transiently abolish lower limb MEPs.
- This MEP alteration is likely due to regional lower limb ischemia rather than direct neural injury.
Implications:
- Intraoperative MEP monitoring during thoracic aortic procedures needs to account for potential femoral cannulation effects.
- Transient MEP changes may not indicate permanent neurological deficits, aiding in accurate surgical decision-making.