title: The incidence of and risk factors for ischemic complications after microsurgical clipping of unruptured middle cerebral artery aneurysms and the efficacy of intraoperative monitoring of somatosensory evoked potentials: A retrospective study.
abstract: OBJECTIVE
  Ischemic complications (ICs) account for 6.7% after microsurgical clipping of unruptured intracranial aneurysms. This study aimed to evaluate the efficacy of somatosensory evoked potential (SSEP) monitoring during microsurgical clipping of unruptured middle cerebral artery (MCA) aneurysms and evaluate the incidence of and risk factors for ischemic complications after clipping of unruptured MCA aneurysms.
  
  
  METHODS
  Herein, 1208 patients with cerebral aneurysms and treated with microsurgical clipping between May 2003 and February 2015 were enrolled. Those with multiple aneurysms, history of head trauma, subarachnoid hemorrhage, bypass and/or endovascular treatment, and intraoperative rupture were excluded. Subsequently, 411 patients with single unruptured MCA aneurysms treated with simple microsurgical clipping were enrolled. Patients were divided into two groups based on the application of SSEP monitoring during surgery.
  
  
  RESULTS
  The IC rate was 0.9% and 5.6% in the SSEP and non-SSEP groups, respectively. Univariate analysis revealed that age≥62.5years, aneurysm size≥4.15mm, temporary clipping, history of hyperlipidemia and stroke, and no-SSEP monitoring were risk factors for ICs. Multivariate logistic regression analysis showed that age≥62.5years (odds ratio [OR]=7.7; 95% confidence interval [95% CI]=1.5-37.7; P=0.011), previous stroke (OR=26.8, 95% CI=2.4-289.2, P=0.007), and inversely SSEP monitoring (OR=0.14, 95% CI 0.02-0.72, P=0.019) were independent risk factors for ICs.
  
  
  CONCLUSIONS
  Clinicians should consider the possibility of IC during microsurgical clipping of unruptured MCA aneurysms in patient≥62.5years and/or a history of stroke. Intraoperative SSEP monitoring is an effective and feasible tool for preventing IC.
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Hyoung Soo
authors.initials: HS
authors.lastname: Byoun
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea. Electronic address: bang7842@snu.ac.kr.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Bang
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Chang Wan
authors.initials: CW
authors.lastname: Oh
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: O-Ki
authors.initials: OK
authors.lastname: Kwon
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Gyojun
authors.initials: G
authors.lastname: Hwang
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Tackeun
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Si Un
authors.initials: SU
authors.lastname: Lee
authors.affiliation: Department of Neurology, Seoul National University Bundang Hospital, Seoul National University Bundang Hospital, 82 Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Seong-Rae
authors.initials: SR
authors.lastname: Jo
authors.affiliation: Department of Neurology, Seoul National University Bundang Hospital, Seoul National University Bundang Hospital, 82 Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea.
authors.forename: Dong-Gun
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Department of Neurology, Seoul National University Bundang Hospital, Seoul National University Bundang Hospital, 82 Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do 13620, Korea. Electronic address: kpark78@naver.com.
authors.forename: Kyung Seok
authors.initials: KS
authors.lastname: Park
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000601:surgery*; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D008866:Microsurgery / Q000009:adverse effects* / Q000706:statistics & numerical data; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Cerebral aneurysm; Ischemic complication; Middle cerebral artery; Somatosensory evoked potential