Article
Motor evoked potentials in supratentorial surgery as diagnostic and surrogate biomarkers
Motorisch evozierte Potenziale in supratentorieller Chirurgie als diagnostische und Surrogat-Biomarker
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Published: | May 25, 2022 |
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Outline
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Objective: The objective of the current study was to assess the diagnostic and surrogate performance of MEPs in supratentorial surgery.
Methods: A systematic search of the literature using PubMed (MEDLINE), Embase, Scopus, CINAHL,and the Cochrane Library was undertaken to retrieve pertinent studies. A Diagnostic Test Accuracy (DTA) analysis of MEPs for postoperative motor deficits and a correlation analysis between reversed intraoperative MEP changes and new postoperative motor deficits were performed. The data were visualized using the RevMan calculator in the Review Manager software (RevMan, version 5.4), MATLAB (version R2020b) and R (version 4.0.2, R-project.org).
Results: The DTA analysis revealed that MEPs have a high specificity and Negative Predictive Value (NPV) for early-transient, transient and permanent motor deficits. Sensitivity and Positive Predictive Value (PPV) estimates were inconsistent across the studies but were rather low or modest in the majority of them. Sensitivity yielded higher values for the threshold criterion compared with the amplitude criterion and PPV appeared to be higher when the mapping and monitoring criteria were combined compared with monitoring criteria alone. Diagnostic accuracy estimates were similar for Transcranial Electrical Stimulation (TES) and Direct Cortical Stimulation (DCS). The correlation analysis showed a negative correlation between the proportion of reversible MEP changes and the proportion of new postoperative motor deficits associated with MEP changes.
Conclusion: As diagnostic markers, MEPs exhibit high specificity and NPV and hence, the absence of irreversible MEP changes can reassure the surgeon both for short-term and long-term preservation of the motor function.However, MEPs display low to modest sensitivity and PPV, meaning that an irreversible MEP change is not associated per se with the occurrence of a postoperative motor deficit, although it is highly possible. The low to modest sensitivity and PPV may be attributed to the low prevalence of reported events.As surrogate markers, MEPs perform well and successful reversal of a MEP alteration following a rescue intervention indicates an unimpaired motor function postoperatively.