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Somatosensory Evoked Potential Changes in Neuroendovascular Procedures: Incidence and Association With Clinical Outcome in 873 Patients

Phillips, Jessica L.H. BA*; Chalouhi, Nohra MD*; Jabbour, Pascal MD*; Starke, Robert M. MD*,‡; Bovenzi, Cory D. BS*; Rosenwasser, Robert H. MD*; Wilent, W. Bryan PhD§; Romo, Victor M. MD; Tjoumakaris, Stavropoula I. MD*

doi: 10.1227/NEU.0000000000000510
Research-Human-Clinical Studies

BACKGROUND: Neurophysiological monitoring is routinely used during neurosurgical procedures. Use of neurophysiological monitoring has extended to neuroendovascular procedures, but evidence of its impact on clinical outcome in this arena is limited.

OBJECTIVE: To report the incidence of significant intraoperative somatosensory evoked potential (SSEP) changes during neuroendovascular surgery and to correlate SSEP changes with clinical outcomes.

METHODS: Patients who underwent neuroendovascular surgery at our institution between 2011 and 2013 were included in the analysis. Medical charts and imaging studies were reviewed retrospectively for sex, age, lesion type and size, clinical presentation, type of endovascular procedure, duration of SSEP change, reversibility of SSEP change, incidence of intraoperative complications and related mortalities, presence of new infarction within 72 hours of intervention, and discharge outcome.

RESULTS: Of 873 consecutive patients, 52 (6%) had clinically significant intraoperative SSEP changes. Twenty-four patients (46%) had SSEP changes that were corrected, and 28 patients (54%) had changes that were not reversed before the end of surgery. Both decreased duration and reversal of SSEP changes were associated with a lower incidence of postoperative infarction and more favorable clinical outcome on discharge. The positive predictive value of an irreversible SSEP change for postoperative infarction in our study was 21%, and the negative predictive value was 83%.

CONCLUSION: The approximate incidence of SSEP changes is 6% during neuroendovascular procedures. Rapid reversal of SSEP changes is associated with better outcomes. SSEP monitoring may be a valuable tool for preventing complications after neuroendovascular interventions.

ABBREVIATIONS: CI, confidence interval

GOS, Glasgow Outcome Scale

NPM, neurophysiological monitoring

NPV, negative predictive value

PPV, positive predictive value

SSEP, somatosensory evoked potential

*Department of Neurological Surgery, Thomas Jefferson University and Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania;

Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia;

§Sentient Medical Systems, Hunt Valley, Maryland; and

Department of Neurosurgical Anesthesia, Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania

Correspondence: Stavropoula I. Tjoumakaris, MD, Assistant Professor, Division of Cerebrovascular Surgery and Endovascular Neurosurgery, Department of Neurological Surgery, Thomas Jefferson University Hospital, 901 Walnut St, 3rd Floor, Philadelphia, PA 19107. E-mail:

Received January 31, 2014

Accepted June 26, 2014

Copyright © by the Congress of Neurological Surgeons