title: Does mechanical filtration of intraoperative cell salvage effectively remove titanium debris generated during instrumented spinal surgery? An in vitro analysis.
abstract: BACKGROUND
  Instrumented fusion of the spine is a surgery commonly performed to stabilize vertebrae causing pain and to correct anatomic deformities. Such surgery can create substantial blood loss. Autotransfusion is a means to limit homologous blood transfusion in this setting. However, a dilemma is created when the high-speed drill used for bone removal comes in contact with implanted titanium spinal hardware. A clinician at this point is forced to decide between two options: to discontinue autotransfusion to avoid the potential transfusion of titanium fragments while risking blood loss and the need for homologous transfusion or to continue autotransfusion while risking transfusion of titanium fragments back into circulation.
  
  
  OBJECTIVE
  To conclusively identify whether titanium fragments created by a high-speed drill are able to pass through standard autotransfusion microaggregate blood filters.
  
  
  METHODS
  A positive and negatively controlled experiment with blinded sample analysis.
  
  
  METHODS
  The presence or absence of titanium alloy on a filter with detection by energy-dispersive X-ray spectroscopy (EDX).
  
  
  METHODS
  A mock autotransfusion setup was devised for in vitro filtering. Six investigational and two control experiments were conducted. Titanium fragments generated by a high-speed drill were aspirated with saline and filtered with standard autotransfusion reservoirs and microaggregate blood filters. A final filter with a 1-μm pore size was placed distal to the blood filters. After filtration was complete, this final filter was analyzed using EDX.
  
  
  RESULTS
  The presence of titanium was confirmed by EDX on five of six investigational filters. The positive and negative control filters were analyzed by EDX and tested positive and negative, respectively, for titanium.
  
  
  CONCLUSIONS
  Standard 40 μm reservoir and blood microaggregate filters do not eliminate the smallest fragments of titanium generated by contact between a high-speed drill and a titanium hardware. The mass of titanium able to elude filtration is very small. The impact of transfusing blood contaminated with such a small mass of titanium is not known.
authors.affiliation: Lutheran Medical Group, 7910 W. Jefferson Ave., Suite 102, Fort Wayne, IN, 46804 USA. Electronic address: jmorton.ioh@gmail.com.
authors.forename: John M
authors.initials: JM
authors.lastname: Morton
authors.affiliation: Fort Wayne Orthopedics, 7601 W Jefferson Blvd, Fort Wayne, IN 46804 USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Rahn
authors.affiliation: Fort Wayne Orthopedics, 7601 W Jefferson Blvd, Fort Wayne, IN 46804 USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Shugart
authors.affiliation: Rush University, College of Health Sciences, Department of Perfusion Technology. Armour Academic Center, 600 S. Paulina Street, Suite 1021, Chicago, IL 60612 USA.
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Wojdyla
mesh_terms: D001804:Blood Transfusion, Autologous / Q000009:adverse effects / Q000379:methods*; D005374:Filtration / Q000379:methods*; D006801:Humans; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods*; D014025:Titanium / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D014025:Titanium
keywords: Autotransfusion; Cell saver; EDX; Spinal fusion; Titanium alloy; Transfusion