title: Injectable gelatin used as hemostatic agent to stop pedicle bleeding in long deformity surgical procedures: does it embolize?
abstract: METHODS
  Prospective porcine animal model.
  
  
  OBJECTIVE
  Determine if injecting FloSeal into pedicles for hemostasis causes emboli.
  
  
  BACKGROUND
  Bleeding from spinal deformity cases can be substantial, especially when surgical procedures involve bilateral fixation at multiple segments. It is not unusual to observe hemorrhage from vascular pedicles during each step of pedicle screw tract preparation. When multiple fixation points are required, blood loss can be excessive. To minimize estimated blood loss and associated morbidity, surgeons have injected liquefied gelatin into pedicles after drilling, palpating, and/or tapping. FloSeal is one of the most popular commercially available injectable agents and we sought to investigate the potential for embolization when used as an intrapedicular hemostatic agent.
  
  
  METHODS
  Two adult minipigs were anesthetized and underwent sequential bilateral pedicle cannulation from T-spine to sacrum. At every level, tracts were cannulated, palpated, and tapped. In every tract, FloSeal was injected into each pedicle until back pressure was detected on the syringe or to a maximum volume of 2 mL, then pedicle screws were inserted. The right ventricular outflow tract was visualized real time using transesophageal echocardiography. Postmortem evaluation of heart and lungs was performed.
  
  
  RESULTS
  FloSeal injected into pedicles caused a consistent large showering of the right ventricular outflow tract in both pigs as visualized on intraoperative transesophageal echocardiography. A second large showering occurred during screw insertion after FloSeal was injected. Microscopic examination of lungs clearly identified amphophilic amorphous material in many small vessels consistent with FloSeal.
  
  
  CONCLUSIONS
  This study suggests caution when injecting gelatin hemostatic agents into pedicles to stop bleeding during spinal surgery as we saw clear evidence of fat and gelatin emboli when used in this animal model. Further investigation into how to minimize this embolic showering may help the cardiopulmonary at risk patient who requires spinal surgery, especially when multiple points of pedicle screw fixation are used.
  
  
  METHODS
  N/A.
authors.affiliation: *Austin Spine Center, Austin TX † Department of Veterinary Medicine and Surgery ‡Department of Veterinary Medicine, Surgery and Biomedical Sciences, and §Veterinary Pathobiology, University of Missouri College of Veterinary Medicine, Columbia, MO ¶Department of Orthopedic Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL; and ‖Department of Orthopedic Surgery, University of Missouri, Columbia, MO.
authors.forename: Craig Allen
authors.initials: CA
authors.lastname: Kuhns
authors.forename: Cristi R
authors.initials: CR
authors.lastname: Cook
authors.forename: John R
authors.initials: JR
authors.lastname: Dodam
authors.forename: Stacey Benton
authors.initials: SB
authors.lastname: Leach
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kuroki
authors.forename: Tyler James
authors.initials: TJ
authors.lastname: Jenkins
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Tallmage
authors.forename: Daniel Gerard
authors.initials: DG
authors.lastname: Hoernschemeyer
mesh_terms: D000818:Animals; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000209:etiology*; D005780:Gelatin / Q000009:adverse effects* / Q000627:therapeutic use; D006490:Hemostatics / Q000009:adverse effects* / Q000627:therapeutic use; D019637:Orthopedic Procedures / Q000379:methods*; D011446:Prospective Studies; D013123:Spinal Fusion / Q000379:methods*; D013552:Swine
chemical_list: D006490:Hemostatics; D005780:Gelatin