Somatosensory and motor evoked potentials (SEPs and MEPs) are often used to prevent ischemic complications during aneurysm surgeries. However, surgeons often encounter cases with suspicious false-positive and false-negative results from intraoperative evoked potential (EP) monitoring, but the incidence and possible causes for these results are not well established. The aim of this study was to investigate the efficacy and reliability of EP monitoring in the microsurgical treatment of intracranial aneurysms by evaluating false-positive and false-negative cases.
From January 2012 to April 2016, 1514 patients underwent surgery for unruptured intracranial aneurysms (UIAs) with EP monitoring at the authors’ institution. An EP amplitude decrease of 50% or greater compared with the baseline amplitude was defined as a significant EP change. Correlations between immediate postoperative motor weakness and EP monitoring results were retrospectively reviewed. The authors calculated the sensitivity, specificity, and positive and negative predictive values of intraoperative MEP monitoring, as well as the incidence of false-positive and false-negative results.
Eighteen (1.19%) of the 1514 patients had a symptomatic infarction, and 4 (0.26%) had a symptomatic hemorrhage. A total of 15 patients showed motor weakness, with the weakness detected on the immediate postoperative motor function test in 10 of these cases. Fifteen false-positive cases (0.99%) and 8 false-negative cases (0.53%) were reported. Therefore, MEP during UIA surgery resulted in a sensitivity of 0.10, specificity of 0.94, positive predictive value of 0.01, and negative predictive value of 0.99.
Intraoperative EP monitoring has high specificity and negative predictive value. Both false-positive and false-negative findings were present. However, it is likely that a more meticulously designed protocol will make EP monitoring a better surrogate indicator of possible ischemic neurological deficits.
BarkerFGIIAmin-HanjaniSButlerWEOgilvyCSCarterBS: In-hospital mortality and morbidity after surgical treatment of unruptured intracranial aneurysms in the United States, 1996–2000: the effect of hospital and surgeon volume. Neurosurgery52:995–10092003
BrilstraEHRinkelGJvan der GraafYSluzewskiMGroenRJLoRT: Quality of life after treatment of unruptured intracranial aneurysms by neurosurgical clipping or by embolisation with coils. A prospective, observational study. Cerebrovasc Dis17:44–522004
BrinjikjiWRabinsteinAANasrDMLanzinoGKallmesDFCloftHJ: Better outcomes with treatment by coiling relative to clipping of unruptured intracranial aneurysms in the United States, 2001–2008. AJNR Am J Neuroradiol32:1071–10752011
GerlachRBeckJSetzerMVatterHBerkefeldJDu Mesnil de RochemontR: Treatment related morbidity of unruptured intracranial aneurysms: results of a prospective single centre series with an interdisciplinary approach over a 6 year period (1999–2005). J Neurol Neurosurg Psychiatry78:864–8712007
HyunSJRhimSC: Combined motor and somatosensory evoked potential monitoring for intramedullary spinal cord tumor surgery: correlation of clinical and neurophysiological data in 17 consecutive procedures. Br J Neurosurg23:393–4002009
IchikawaTSuzukiKSasakiTMatsumotoMSakumaJOinumaM: Utility and the limit of motor evoked potential monitoring for preventing complications in surgery for cerebral arteriovenous malformation. Neurosurgery67 (3 Suppl Operative):ons222–ons2282010
KimWHLeeJJLeeSMParkMNParkSKSeoDW: Comparison of motor-evoked potentials monitoring in response to transcranial electrical stimulation in subjects undergoing neurosurgery with partial vs no neuromuscular block. Br J Anaesth110:567–5762013
MotoyamaYKawaguchiMYamadaSNakagawaINishimuraFHironakaY: Evaluation of combined use of transcranial and direct cortical motor evoked potential monitoring during unruptured aneurysm surgery. Neurol Med Chir (Tokyo)51:15–222011
SakumaJSuzukiKSasakiTMatsumotoMOinumaMKawakamiM: Monitoring and preventing blood flow insufficiency due to clip rotation after the treatment of internal carotid artery aneurysms. J Neurosurg100:960–9622004
SchichorCRachingerWMorhardDZausingerSHeiglTJReiserM: Intraoperative computed tomography angiography with computed tomography perfusion imaging in vascular neurosurgery: feasibility of a new concept. J Neurosurg112:722–7282010
SuzukiKMikamiTSuginoTWanibuchiMMiyamotoSHashimotoN: Discrepancy between voluntary movement and motor-evoked potentials in evaluation of motor function during clipping of anterior circulation aneurysms. World Neurosurg82:e739–e7452014
SzelényiAKothbauerKde CamargoABLangerDFlammESDeletisV: Motor evoked potential monitoring during cerebral aneurysm surgery: technical aspects and comparison of transcranial and direct cortical stimulation. Neurosurgery57 (4 Suppl):331–3382005
SzelényiALangerDKothbauerKDe CamargoABFlammESDeletisV: Monitoring of muscle motor evoked potentials during cerebral aneurysm surgery: intraoperative changes and postoperative outcome. J Neurosurg105:675–6812006
TakebayashiSKamiyamaHTakizawaKKobayashiTSaitohN: The significance of intraoperative monitoring of muscle motor evoked potentials during unruptured large and giant cerebral aneurysm surgery. Neurol Med Chir (Tokyo)54:180–1882014