title: Cardiovascular changes during multiple vertebroplasty with and without vent-hole: an experimental study in sheep.
abstract: METHODS
  An experimental study of cardiovascular complications arising during vertebroplasty (VP) of multiple levels.
  
  
  OBJECTIVE
  To investigate the cardiovascular changes during multiple VP and whether a vent-hole has a preventive effect.
  
  
  BACKGROUND
  An experimental study and clinical reports showed that fat embolism (FE) and acute hypotension occur during VP. There is the concern that these complications may worsen during VP of multiple levels. Vent-holes may prevent FE during VP.
  
  
  METHODS
  In twenty-two sheep, four vertebral bodies were augmented with polymethylmethacrylate (PMMA). In ten sheep, a vent-hole was drilled into the pedicle contralateral to the injection site. Heart rate, arterial, central venous and pulmonary artery pressure, cardiac output and blood gas values were recorded. The lungs were subjected to histologic evaluation at postmortem.
  
  
  RESULTS
  The consecutive augmentation of four vertebral bodies with PMMA induced a cumulative FE that gradually deteriorated baseline mean arterial blood pressure (MABP) and blood gas values. The deterioration of MABP and change in blood gas values were attenuated, when a vent-hole was drilled. The amount of intravascular fat in the lungs after multiple VP (19%) was reduced when a vent-hole was drilled (9%).
  
  
  CONCLUSIONS
  Surgeons should be aware of the potential cardiovascular complications during VP of multiple levels. In the clinical setting, a needle in the contralateral pedicle could be used to decompress the vertebral body during the injection of bone cement.
authors.affiliation: Department of Orthopaedic Surgery, University of Otago, Dunedin, New Zealand. niklaus.aebli@stonebow.otago.ac.nz
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Aebli
authors.forename: Jörg
authors.initials: J
authors.lastname: Krebs
authors.forename: Daryl
authors.initials: D
authors.lastname: Schwenke
authors.forename: Gerard
authors.initials: G
authors.lastname: Davis
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Theis
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001843:Bone Cements / Q000494:pharmacology; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000187:drug effects; D002496:Central Venous Pressure / Q000187:drug effects; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D008168:Lung / Q000098:blood supply / Q000473:pathology; D019637:Orthopedic Procedures / Q000379:methods*; D010100:Oxygen / Q000097:blood; D019904:Polymethyl Methacrylate / Q000494:pharmacology; D011651:Pulmonary Artery / Q000187:drug effects / Q000502:physiology; D012756:Sheep; D013131:Spine / Q000187:drug effects / Q000601:surgery*
chemical_list: D001843:Bone Cements; D002245:Carbon Dioxide; D019904:Polymethyl Methacrylate; D010100:Oxygen