title: Patent foramen ovale and brain microembolization during scoliosis surgery in adolescents.
abstract: METHODS
  A case series is reported.
  
  
  OBJECTIVE
  To improve understanding of the potential mechanisms associated with cerebral microemboli during scoliosis surgery in adolescents.
  
  
  BACKGROUND
  Paradoxical cerebral fat microembolization during scoliosis surgery has been associated with right-to-left shunting through an undetected patent foramen ovale. The prevalence of this cardiac defect in the adult population may be as high as 15% to 25%. Although the clinical relevance of this embolic phenomenon during scoliosis surgery has not been investigated, a few reports have documented its fatal consequences. It has been suspected in some patients with postoperative reduced visual function, particularly after complex instrumented fusions.
  
  
  METHODS
  Bilateral transcranial Doppler (2 MHz) was used to monitor cerebral microemboli in the right and left middle cerebral arteries during spinal instrumentation and fusion in four patients. Additionally, transthoracic or transesophageal echocardiography incorporating pulse and color Doppler (3.5-5 MHz) and a contrast test was used in these patients to detect atrial shunts.
  
  
  RESULTS
  Intraoperative transcranial Doppler monitoring detected high rates of cerebral microemboli associated with the presence of an atrial communication in two adolescents. In two additional patients with no detected brain microembolization, echocardiographic examination indicated the absence of an atrial shunt.
  
  
  CONCLUSIONS
  The study findings suggest that unrecognized atrial communications in adolescents undergoing scoliosis surgery contribute to higher rates of Doppler-detected cerebral microemboli than those found in adolescents without this congenital defect.
authors.affiliation: Division of Cardiology, Department of Pediatrics, Children's Hospital of Eastern Ontario and University of Ottawa, Ottawa, Ontario, Canada. Rrodriguez@Ottawaheart.ca
authors.forename: R A
authors.initials: RA
authors.lastname: Rodriguez
authors.forename: B
authors.initials: B
authors.lastname: Sinclair
authors.forename: D
authors.initials: D
authors.lastname: Weatherdon
authors.forename: M
authors.initials: M
authors.lastname: Letts
mesh_terms: D000293:Adolescent; D002536:Cerebral Arteries / Q000000981:diagnostic imaging; D017548:Echocardiography, Transesophageal; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000150:complications* / Q000000981:diagnostic imaging; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods; D012600:Scoliosis / Q000150:complications* / Q000601:surgery*; D013687:Telencephalon / Q000098:blood supply*; D017585:Ultrasonography, Doppler, Transcranial