title: A porous bioactive titanium implant for spinal interbody fusion: an experimental study using a canine model.
abstract: OBJECTIVE
  Porous biomaterials with adequate pore structure and appropriate mechanical properties are expected to provide a new generation of devices for spinal interbody fusion because of their potential to eliminate bone grafting. The purpose of this study was to evaluate the fusion characteristics of porous bioactive titanium implants using a canine anterior interbody fusion model.
  
  
  METHODS
  Porous titanium implants sintered with volatile spacer particles (porosity 50%, average pore size 303 microm, compressive strength 116.3 MPa) were subjected to chemical and thermal treatments that give a bioactive microporous titania layer on the titanium surface (BT implant). Ten adult female beagle dogs underwent anterior lumbar interbody fusion at L6-7 using either BT implants or nontreated (NT) implants, followed by posterior spinous process wiring and facet screw fixation. Radiographic evaluations were performed at 1, 2, and 3 months postoperatively using X-ray fluoroscopy. Animals were killed 3 months postoperatively, and fusion status was evaluated by manual palpation and histological examination.
  
  
  RESULTS
  Interbody fusion was confirmed in all five dogs in the BT group and three of five dogs in the NT group. Histological examination demonstrated a large amount of new bone formation with marrowlike tissue in the BT implants and primarily fibrous tissue formation in the NT implants.
  
  
  CONCLUSIONS
  Bioactive treatment effectively enhanced the fusion ability of the porous titanium implants. These findings, coupled with the appropriate mechanical properties in load-bearing conditions, indicate that these porous bioactive titanium implants represent a new generation of biomaterial for spinal interbody fusion.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. m.take@kuhp.kyoto-u.ac.jp
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takemoto
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Fujibayashi
authors.forename: Masashi
authors.initials: M
authors.lastname: Neo
authors.forename: Kazutaka
authors.initials: K
authors.lastname: So
authors.forename: Norihiro
authors.initials: N
authors.lastname: Akiyama
authors.forename: Tomiharu
authors.initials: T
authors.lastname: Matsushita
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kokubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible; D004285:Dogs; D004867:Equipment Design; D005260:Female; D016268:Internal Fixators; D008159:Lumbar Vertebrae; D008422:Materials Testing; D016348:Osseointegration; D016062:Porosity; D013123:Spinal Fusion / Q000295:instrumentation*; D014025:Titanium
chemical_list: D020099:Coated Materials, Biocompatible; D014025:Titanium