title: Instrumented Lumbar Corpectomy and Spinal Reconstruction Comparing rhBMP-2/Compression-Resistant Matrix, rhBMP-2/Absorbable Collagen Sponge/Ceramic Granules Mixture, and Autograft in Two Different Devices: A Study in Sheep.
abstract: METHODS
  Fusion success with rhBMP-2 and autograft in titanium or PEEK corpectomy devices was evaluated in a sheep lumbar corpectomy model. The 6 treatment groups included titanium mesh or PEEK corpectomy devices filled with rhBMP-2 on a compression-resistant matrix (CRM) carrier; rhBMP-2 in a morselized absorbable collagen sponge (ACS) carrier combined with resorbable ceramic granules; and autograft.
  
  
  OBJECTIVE
  The aim of this study was to determine fusion rates associated with 2 different preparations of rhBMP-2 as well as autograft in an instrumented ovine lumbar corpectomy model 6 months postoperatively.
  
  
  BACKGROUND
  Vertebral reconstruction with corpectomy devices requires bone graft. Bone graft substitutes have the potential to avoid a second operation, donor site pain, and attendant morbidity associated with autograft.
  
  
  METHODS
  Twenty-four sheep in 6 treatment groups underwent lumbar corpectomy via a retroperitoneal trans-psoas approach. Spines were reconstructed with autograft, rhBMP-2 on a CRM, or rhBMP-2 on an ACS mixed with ceramic granules. Grafting materials were placed in either a titanium mesh or PEEK conduit in spines with internal fixation. Computed tomographic (CT) scans were evaluated for fusion. Undecalcified histology was used to evaluate for fusion as well as the amount and extent of graft incorporation and graft resorption.
  
  
  RESULTS
  Regardless of corpectomy device used, rhBMP-2/CRM or rhBMP-2/ACS with MASTERGRAFT resulted in a 100% fusion rate. The autograft group had a lower (75%) radiographic fusion rate. Using either preparation of rhBMP-2 resulted in the length of the defect filling with solid bone. Autograft fragments and ceramic granules were incorporated into the fusion masses with much of the ceramic granules being resorbed by 6 months.
  
  
  CONCLUSIONS
  Both of the rhBMP-2 formulations have the potential to effect bony fusion and vertebral reconstruction within the corpectomy devices.
authors.affiliation: *Department of Orthopaedic Surgery, The Medical College of Wisconsin Inc., Milwaukee, WI†OrthoIndy, Indianapolis, IN‡Goodman Campbell Brain and Spine, Indianapolis, IN§Orthopedic Center of Illinois, Springfield, IL.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Toth
authors.forename: David G
authors.initials: DG
authors.lastname: Schwartz
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Mobasser
authors.forename: Joseph
authors.initials: J
authors.lastname: Williams
mesh_terms: D000818:Animals; D064592:Autografts / Q000637:transplantation*; D001577:Benzophenones; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D002516:Ceramics / Q000494:pharmacology; D003094:Collagen / Q000494:pharmacology*; D005260:Female; D007659:Ketones / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D011108:Polymers; D011474:Prosthesis Design; D011994:Recombinant Proteins / Q000494:pharmacology; D012756:Sheep; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D001577:Benzophenones; D055396:Bone Morphogenetic Protein 2; D007659:Ketones; D011108:Polymers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C063834:polyetheretherketone; D011092:Polyethylene Glycols; D003094:Collagen