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Published on: March 26, 2019
An evaluation of motor evoked potential surrogate endpoints during intracranial vascular procedures
R N Holdefer1, D B MacDonald2, L Guo3
1Department of Rehabilitation Medicine, University of Washington School of Medicine, Box 359740, Seattle, WA 98104-2499, USA.
Objective:
MEPs are used as surrogate endpoints to predict the effectiveness of interventions, made in response to MEP deterioration, in avoiding new postoperative deficits. MEP performance in capturing intervention effects on these outcomes was investigated.
Methods:
A meta-analysis of studies using MEPs during intracranial vascular surgeries between 2003 and 2014 was performed. MEP diagnostic performance and relative risk of new postoperative deficits for reversible compared with irreversible MEP changes were determined. Intervention efficacy in reversing MEP deterioration and postoperative outcomes was compared across studies.
Results:
MEP diagnostic performance compared favorably with that of other tests used in medicine, with all likelihood ratios >10. The summary relative risk comparing reversible and irreversible changes was 0.40, indicating a 60% decrease in new deficits for reversible MEP changes. The proportion of MEP deteriorations which recovered was negatively correlated with the proportion of new postoperative deficits (r=-0.81, p<.005).
Conclusions:
The effectiveness of interventions in recovering an MEP decline was predictive of preserved neurologic status. MEPs are provisionally qualified as surrogate endpoints given potentially major harms to the patient if they are not used, compared to the minimal harms and costs associated with their use.
Significance:
The performance of MEPs as substitute, or surrogate, endpoints during intracranial vascular surgeries for new deficits in motor strength in the immediate postoperative period was directly assessed for ten recent studies.
Insights
Motor Evoked Potentials (MEPs) effectively predict intervention success in preventing postoperative deficits during intracranial vascular surgery. Recovering MEP decline correlates with preserved neurological function, supporting their role as surrogate endpoints.
Area of Science:
- Neurosurgery
- Neurology
- Clinical Trials
Background:
- Motor Evoked Potentials (MEPs) are utilized as surrogate endpoints to assess the efficacy of interventions aimed at preventing new postoperative deficits.
- Investigating MEP performance in capturing intervention effects on these outcomes is crucial for surgical decision-making.
Purpose of the Study:
- To evaluate the effectiveness of MEPs as surrogate endpoints in intracranial vascular surgeries.
- To determine the diagnostic performance of MEPs and their correlation with postoperative deficits.
Main Methods:
- A meta-analysis of studies published between 2003 and 2014 involving MEPs during intracranial vascular surgeries.
- Assessed MEP diagnostic performance and the relative risk of new postoperative deficits for reversible versus irreversible MEP changes.
- Compared intervention efficacy in reversing MEP deterioration and subsequent postoperative outcomes.
Main Results:
- MEP diagnostic performance was favorable, with likelihood ratios exceeding 10.
- Reversible MEP changes were associated with a 60% reduction in new postoperative deficits (relative risk = 0.40).
- A significant negative correlation (r=-0.81, p<.005) was found between MEP recovery and the incidence of new postoperative deficits.
Conclusions:
- Intervention effectiveness in reversing MEP decline predicts preserved neurological status.
- MEPs are provisionally qualified as surrogate endpoints due to their predictive value and minimal associated harms/costs.
- MEPs demonstrated reliable performance as surrogate endpoints for motor strength deficits in the immediate postoperative period following intracranial vascular surgery.
