title: Direct Bypass Versus Indirect Bypass in Adult Moyamoya Angiopathy with Symptoms or Hemodynamic Instability: A Meta-analysis of Comparative Studies.
abstract: BACKGROUND
  It remains controversial which bypass methods are optimal for treating adult moyamoya angiopathy patients. This study aimed to analyze the literature about whether different bypass methods affect differently outcome results of adult moyamoya patients with symptoms or hemodynamic instability.
  
  
  METHODS
  A systematic search of the PubMed, Embase, and Cochrane Central databases was performed for articles published between 1990 and 2015. Comparative studies about the effect of direct or combined bypass (direct bypass group) and indirect bypass (indirect bypass group) in patients with moyamoya angiopathy at 18 years of age or older were selected. For stroke incidence at the end of the follow-up period, the degree of angiographic revascularization, hemodynamic improvement, and perioperative complication rates within 30 days, pooled relative risks were calculated between the 2 groups with a 95% confidence interval.
  
  
  RESULTS
  A total of 8 articles (including 536 patients and 732 treated hemispheres) were included in the meta-analysis. There were no significant differences between the 2 groups when we compared the overall stroke rate, the hemodynamic improvement rate, or the perioperative complication rate at the end of the follow-up period. The direct bypass group, however, had a lower risk than the indirect bypass group for obtaining a poor angiographic revascularization rate (risk ratio, 0.35; 95% confidence interval, 0.15-0.84; P = 0.02).
  
  
  CONCLUSIONS
  The current meta-analysis suggests that the direct or combined bypass surgical method is better for angiographic revascularization in adult moyamoya patients with symptoms or hemodynamic instability. Future studies may be necessary to confirm these findings.
authors.affiliation: Department of Neurosurgery, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea.
authors.forename: Hoon
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea. Electronic address: argus3620@gmail.com.
authors.forename: Dong-Kyu
authors.initials: DK
authors.lastname: Jang
authors.affiliation: Department of Neurosurgery, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Sung
authors.affiliation: Department of Neurosurgery, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Bucheon, Korea.
authors.forename: Ik Seong
authors.initials: IS
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kwan-Sung
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea.
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Department of Neurosurgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Korea.
authors.forename: Pil Woo
authors.initials: PW
authors.lastname: Huh
authors.affiliation: Department of Neurosurgery, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea.
authors.forename: Young Sup
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Myong-Ji St. Mary's Hospital, Seoul, Korea.
authors.forename: Dal-Soo
authors.initials: DS
authors.lastname: Kim
authors.affiliation: Department of Medical Statistics, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kyung-Do
authors.initials: KD
authors.lastname: Han
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015984:Causality; D002548:Cerebral Revascularization / Q000379:methods* / Q000706:statistics & numerical data*; D015897:Comorbidity; D005260:Female; D006801:Humans; D038622:Internationality; D008297:Male; D008875:Middle Aged; D009072:Moyamoya Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D015995:Prevalence; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D055815:Young Adult
keywords: Adult; Bypass; Direct; Indirect; Meta-analysis; Moyamoya