title: Evaluating Osseointegration Into a Deeply Porous Titanium Scaffold: A Biomechanical Comparison With PEEK and Allograft.
abstract: METHODS
  This was a biomechanical push-out testing study using a porcine model.
  
  
  OBJECTIVE
  The purpose was to evaluate the strength of implant-bone interface of a porous titanium scaffold by comparing it to polyetheretherketone (PEEK) and allograft.
  
  
  BACKGROUND
  Osseointegration is important for achieving maximal stability of spinal fusion implants and it is desirable to achieve as quickly as possible. Common PEEK interbody fusion implants appear to have limited osseointegration potential because of the formation of fibrous tissue along the implant-bone interface. Porous, three-dimensional titanium materials may be an option to enhance osseointegration.
  
  
  METHODS
  Using the skulls of two swine, in the region of the os frontale, 16 identical holes (4 mm diameter) were drilled to 10 mm depth in each skull. Porous titanium, PEEK, and allograft pins were press fit into the holes. After 5 weeks, animals were euthanized and the skull sections with the implants were cut into sections with each pin centered within a section. Push-out testing was performed using an MTS machine with a push rate of 6 mm/min. Load-deformation curves were used to compute the extrinsic material properties of the bone samples. Maximum force (N) and shear strength (MPa) were extracted from the output to record the bonding strength between the implant and surrounding bone. When calculating shear strength, maximum force was normalized by the actual implant surface area in contact with surrounding bone.
  
  
  RESULTS
  Mean push-out shear strength was significantly greater in the porous titanium scaffold group than in the PEEK or allograft groups (10.2 vs. 1.5 vs. 3.1 MPa, respectively; P < 0.05).
  
  
  CONCLUSIONS
  The push-out strength was significantly greater for the implants with porous titanium coating compared with the PEEK or allograft. These results suggest that the material has promise for facilitating osseointegration for implants, including interbody devices for spinal fusion.
  
  
  METHODS
  N/A.
authors.affiliation: Texas Back Institute, Plano, TX.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Guyer
authors.affiliation: California Spine Group, San Diego, CA.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Abitbol
authors.affiliation: Texas Back Institute Research Foundation, Plano, TX.
authors.forename: Donna D
authors.initials: DD
authors.lastname: Ohnmeiss
authors.affiliation: Nanovis, LLC, Columbia City, IN.
authors.forename: Chang
authors.initials: C
authors.lastname: Yao
mesh_terms: D064591:Allografts; D000818:Animals; D001577:Benzophenones; D001696:Biomechanical Phenomena / Q000502:physiology; D007659:Ketones; D008422:Materials Testing; D016348:Osseointegration / Q000502:physiology*; D011092:Polyethylene Glycols; D011108:Polymers; D013552:Swine; D054457:Tissue Scaffolds; D014025:Titanium
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D014025:Titanium