title: Reversible occlusion of donor vessel caused by mouth opening after superficial temporal artery-middle cerebral artery anastomosis in adult moyamoya patients.
abstract: OBJECTIVE
  The authors experienced an intriguing phenomenon in 2 adult patients with moyamoya disease. Mouth opening caused reversible occlusion of the donor superficial temporal artery (STA), and the patients exhibited transient cerebral ischemic symptoms. The aim of this study was to assess the incidence of such occlusion and the mechanism of this phenomenon.
  
  
  METHODS
  Twelve consecutive adult patients with moyamoya disease (15 affected sides) who underwent STA-middle cerebral artery anastomosis were included in this study. Ultrasound examination was performed more than 3 months postoperatively to determine whether mouth opening affected blood flow of the donor STA and led to any ischemic symptoms within 1 minute. Computed tomography angiography was performed during both mouth opening and mouth closing, when blood flow changes of the donor STA were recognized.
  
  
  RESULTS
  Under wide mouth opening, steno-occlusion of the donor STA occurred in 5 of 15 sides (33.3%). On 1 side (6.7%), complete occlusion induced ischemic symptoms. Steno-occlusion occurred by at least 2 mechanisms: either the stretched temporalis muscle pushed the donor STA against the edge of the bone window, or the redundant donor STA kinked when the muscle was stretched.
  
  
  CONCLUSIONS
  Even with temporary occlusion of the donor STA, ischemic symptoms seem to rarely occur. However, to avoid the "big bite ischemic phenomenon," the authors recommend securing a sufficient distance between the donor STA and the edge of the bone window and avoiding a redundant course of the donor STA within the muscle layer.
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Katsuta
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Abe
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Miki
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, Fukuoka University, Fukuoka, Japan.
authors.forename: Tooru
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000714:Anastomosis, Surgical / Q000009:adverse effects* / Q000379:methods; D002545:Brain Ischemia / Q000209:etiology*; D002548:Cerebral Revascularization / Q000009:adverse effects* / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000601:surgery*; D009055:Mouth; D009068:Movement; D009072:Moyamoya Disease / Q000601:surgery*; D013699:Temporal Arteries / Q000601:surgery*
keywords: CTA = computed tomography angiography; EMS = encephalomyosynangiosis; MCA = middle cerebral artery; STA = superficial temporal artery; extracranial-intracranial bypass; mouth opening; moyamoya disease; occlusion; superficial temporal artery; temporalis muscle; vascular disorders