title: Endoscopic instrumented posterolateral lumbar fusion with Healos and recombinant human growth/differentiation factor-5.
abstract: OBJECTIVE
  The goal of this study was to use a minimally invasive endoscopic surgical technique in a sheep model to evaluate the efficacy of an osteoinductive growth factor, recombinant human growth/differentiation factor-5 (also designated MP52), and an osteoconductive matrix formulation (Healos; DePuy AcroMed, Inc., Mountain View, CA) for inducing and facilitating bone formation.
  
  
  METHODS
  Twelve mature sheep underwent bilateral posterolateral lumbar fusion and pedicle screw fixation via a posterior endoscopic approach. Each sheep received two different types of graft material, autogenous iliac crest bone, or a bone graft substitute (MP52 with Healos), inserted into the right and left sides of the spine in an alternating fashion. Groups of four sheep were killed at 2, 4, and 6 months postoperatively for manual, radiographic, and histological evaluation.
  
  
  RESULTS
  No neurological impairments, infections, or other complications were observed. After 2 months, partial fusion on both sides was observed, but radiographic evaluation showed greater bone growth on the side that received the bone graft substitute. Solid posterolateral fusion was observed in both autograft and bone graft substitute sites at 4 and 6 months, and autograft and Healos MP52 fusion sites were essentially the same at histological examination. There was no abnormal overgrowth of new bone from either of these two materials.
  
  
  CONCLUSIONS
  Endoscopic posterolateral lumbar arthrodesis and instrumentation is feasible, safe, and effective in a sheep model. Healos is a useful bonding agent that mimics natural bone in posterolateral intertransverse fusion sites. Combined with MP52, it produced fusion comparable to that of autogenous bone graft. Minimally invasive techniques and bone graft substitutes could eliminate morbidity and increase the likelihood of successful fusion.
authors.affiliation: Department of Neurosurgery, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Tae-Ahn
authors.initials: TA
authors.lastname: Jahng
authors.forename: Tsai-Sheng
authors.initials: TS
authors.lastname: Fu
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Cunningham
authors.forename: Anton E
authors.initials: AE
authors.lastname: Dmitriev
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D001863:Bone Screws; D018786:Bone Substitutes / Q000008:administration & dosage*; D016025:Bone Transplantation; D024042:Collagen Type I / Q000008:administration & dosage*; D055428:Growth Differentiation Factor 5; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D044583:Neuroendoscopy / Q000379:methods*; D011994:Recombinant Proteins / Q000008:administration & dosage; D012756:Sheep; D013123:Spinal Fusion / Q000379:methods*; D013997:Time Factors
chemical_list: D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D024042:Collagen Type I; C525893:GDF5 protein, human; D055428:Growth Differentiation Factor 5; D011994:Recombinant Proteins