Impact of Changes in Intraoperative Somatosensory Evoked Potentials on Stroke Rates After Clipping of Intracranial Aneurysms

Abstract

Intraoperative SSEP changes are more reliable in unruptured aneurysm cases than in ruptured cases. Whereas irreversible changes in unruptured cases were associated with an 80% stroke rate, such changes in ruptured cases did not have any adverse ischemic sequelae in 58% of patients. This information is helpful during the intraoperative assessment of reported SSEP changes.

Intraoperative Evoked Potentials: A Review of Clinical Impact and Limitations

“…Moreover, Clark et al (N=277) intervention anterior circulation aneurysms with SSEP monitoring. Hence, an amplitude decrease over 50% reversed after procedure's adjustment demonstrated better neurologic outcomes than a persistent decline [28].…”

“…In neurovascular surgery, SSEP changes reversibility and decreased duration, based on presentation and discharge evaluation, were associated with a more favorable outcome [28,36]. There was SSEP signal deterioration in 4% of the patients and its sensitivity was 25%, also, overall positive predictive value was about 30% [36].…”

“…Indeed, for unruptured aneurysm procedures, positive predictive value is 40% against 22% in ruptured ones. For instance, irreversible SSEP decline in unruptured aneurysms procedures were followed by stroke in 80% while the same waveform behavior, in ruptured ones, represented 76% false results plus cases of stroke remain undetected in 72% [28].…”

“…However, correlation between SSEP changes and ischemia is well defined even though time to infarction is not clear [36]. Plus, may not be obtainable after mielectomy in about 30% of the patients [2,4,28].…”

“…Some authors attribute SSEP positive predictive value deterioration to edematous cerebral matter. Interestingly, Wicks et al pointed that irreversible changes in unruptured ones had 80% stroke rate, while similar changes in ruptured may develop without stroke in 58% [28,36].…”