title: A preliminary study of platelet activation after embolization of marrow contents.
abstract: OBJECTIVE
  Intravasation of bone marrow contents into venous circulation and pulmonary embolization after intramedullary nailing may be coupled with the activation of coagulation and fibrinolytic cascades. The objective of this study was to assess hemostatic response to pulmonary extravasated marrow contents. We hypothesize that activation of platelet activity and the coagulation cascade may occur after embolization of marrow contents in an experimental animal model of intramedullary nailing.
  
  
  METHODS
  Fifteen New Zealand white male rabbits were randomly assigned to control or fat embolism (FE) groups. In the FE group (n = 8), femurs were surgically instrumented with retrograde intramedullary nails and pressurized with bone cement. In the control group (n = 7), a sham knee incision was made that was immediately closed without drilling, reaming, or pressurization. Fibrinogen, D-dimer latex screen assay, 1 stage prothrombin time, and activated partial thromboplastin time were analyzed.
  
  
  RESULTS
  As the main platelet activation indicators, the marker Annexin-V percent binding increased in the FE group at 2 hours (P = 0.04) and 4 hours (P = 0.04), and the marker CD62P percent expression increased in the FE group at 2 hours (P = 0.04).
  
  
  CONCLUSIONS
  This preliminary study showed that pressurization of marrow and intravasation of fat and marrow products cause activation of platelets and the coagulation cascade, with or without tissue trauma. This may be relevant to the treatment of multiply injured patients with prior respiratory and coagulation abnormalities. A future larger study may be needed.
authors.affiliation: Martin Orthopaedic Biomechanics Laboratory, St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Blankstein
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Byrick
authors.forename: Masaki
authors.initials: M
authors.lastname: Nakane
authors.forename: Annie K W
authors.initials: AK
authors.lastname: Bang
authors.forename: John
authors.initials: J
authors.lastname: Freedman
authors.forename: M B
authors.initials: MB
authors.lastname: Garvey
authors.forename: Rad
authors.initials: R
authors.lastname: Zdero
authors.forename: Emil H
authors.initials: EH
authors.lastname: Schemitsch
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology*; D004620:Embolism, Fat / Q000209:etiology* / Q000276:immunology*; D004621:Embolization, Therapeutic / Q000009:adverse effects*; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects*; D008297:Male; D010865:Pilot Projects; D015539:Platelet Activation / Q000276:immunology*; D011817:Rabbits