title: The safety of OP-1 for lumbar fusion with decompression-- a canine study.
abstract: OBJECTIVE
  Bone morphogenetic proteins can serve as adjuncts to autologous bone to achieve bony fusion, and recombinant BMPs such as osteogenic protein-1 (OP-1) have the potential to replace autologous bone altogether as fusion substrate. However, relatively little is known about the safety of OP-1 for spinal fusion procedures. This study examined the effects of OP-1 intentionally placed in the subarachnoid space following thecal sac decompression, and used as graft substrate in a canine dorsolateral lumbar spine fusion model.
  
  
  METHODS
  Lumbar decompression with dorsolateral fusion was performed on 30 canines. The dura was opened to simulate an intraoperative rent and OP-1 was placed in the subarachnoid space and in the fusion bed. Animals were sacrificed after 16 weeks and the spines were examined manually, radiographically and pathologically.
  
  
  RESULTS
  All animals treated with OP-1 developed new bone in the subarachnoid space. This bone compressed the spinal cord, but no clinical or pathological features of neurotoxicity were noted. Mild spinal stenosis was noted at the site of dural decompression in the OP-1 treated animals. Over 80% of animals treated with OP-1 developed fusion as assessed by palpation (52% by CT criteria), while only 25% of control animals fused.
  
  
  CONCLUSIONS
  Recombinant human OP-1 is effective at promoting fusion in a canine dorsolateral lumbar spine fusion model. However, bone growth can occur over exposed, decompressed dura, and it can form in the subdural and subarachnoid spaces. The use of OP-1 as an adjunct to spinal fusion appears to have merit, but its use must be carefully controlled to avoid unwanted bone formation and subsequent neural compression.
authors.affiliation: Department of Surgery, The University of Alabama at Birmingham, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: Paramore
authors.forename: C
authors.initials: C
authors.lastname: Lauryssen
authors.forename: M J
authors.initials: MJ
authors.lastname: Rauzzino
authors.forename: V R
authors.initials: VR
authors.lastname: Wadlington
authors.forename: C A
authors.initials: CA
authors.lastname: Palmer
authors.forename: A
authors.initials: A
authors.lastname: Brix
authors.forename: S C
authors.initials: SC
authors.lastname: Cartner
authors.forename: M N
authors.initials: MN
authors.lastname: Hadley
mesh_terms: D000818:Animals; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000009:adverse effects* / Q000627:therapeutic use*; D019299:Decompression, Surgical; D004285:Dogs; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D011184:Postoperative Period; D011859:Radiography; D011994:Recombinant Proteins; D013116:Spinal Cord / Q000473:pathology; D013123:Spinal Fusion; D013131:Spine / Q000473:pathology; D016212:Transforming Growth Factor beta
chemical_list: C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta