title: Bone ingrowth and vascular supply in experimental spinal fusion with platelet-rich plasma.
abstract: METHODS
  Prospective investigation using a posterolateral spinal fusion (PLSF) model in rabbits.
  
  
  OBJECTIVE
  To assess the effects of platelet-rich plasma (PRP) alone, or with uncultured bone marrow, on bone ingrowth and angiogenesis in experimental PLSF.
  
  
  BACKGROUND
  PRP is an autologous substance potentially beneficial to spinal fusion, because it includes several growth factors that may stimulate bone ingrowth and angiogenesis. However, the results of experimental and clinical investigations on the effectiveness of PRP in spinal fusion are controversial. This study was aimed at analyzing the influence of PRP on bone ingrowth and angiogenesis in experimental PLSF.
  
  
  METHODS
  Twenty White New Zealand rabbits underwent PLSF at L4-L5 level. The graft material included a ceramic carrier (Pro-Osteon 500R) loaded, in 7 rabbits, with PRP alone on the right side (group 1A) and with uncultured bone marrow in the left side (group 1B). In 7 rabbits, the ceramic carrier was used alone in the right side (group 2A), and with uncultured bone marrow in the left side (group 2B). Six rabbits (group 3) were sham operated on both right and left sides. Six months after surgery, the lumbar spine was harvested en bloc and evaluated by high-resolution radiographs (Faxitron, Wheeling, IL) and histology.
  
  
  RESULTS
  The radiographical outcome showed a fusion rate of 86% in groups 1A, 1B, and 2B and a fusion rate of 71% in group 2A. No specimen showed a solid fusion in the sham group. Histological analysis revealed new bone formation in the periapophyseal area in groups 1 and 2, but a complete bony bridge between the transverse processes was not observed in any specimen. In all groups, vascular density was significantly greater in the peri- compared with the interapophyseal region. In the PRP group, there was no evidence of increased vascular density in the grafted material compared with the other groups.
  
  
  CONCLUSIONS
  In experimental PLSF model in rabbits, PRP was not effective in promoting new bone formation and vascularization.
authors.affiliation: Department of Anatomy, Histology, Legal Medicine and Orthopaedics, University La Sapienza, Piazzale Aldo Moro, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Cinotti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Corsi
authors.forename: Benedetto
authors.initials: B
authors.lastname: Sacchetti
authors.forename: Mara
authors.initials: M
authors.lastname: Riminucci
authors.forename: Paolo
authors.initials: P
authors.lastname: Bianco
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giannicola
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D016723:Bone Remodeling; D018786:Bone Substitutes; D002516:Ceramics; D007150:Immunohistochemistry; D008159:Lumbar Vertebrae / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D018919:Neovascularization, Physiologic; D053657:Platelet-Rich Plasma; D011817:Rabbits; D011859:Radiography; D013123:Spinal Fusion / Q000379:methods*; D013997:Time Factors
chemical_list: D018786:Bone Substitutes