Browsing by Author "Pizarro, Felipe"

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    Autograft versus allograft with or without demineralized bone matrix in posterolateral lumbar fusion in rabbits - Laboratory investigation
    (AMER ASSOC NEUROLOGICAL SURGEONS, 2008) Urrutia, Julio; Thumm, Nicolas; Apablaza, Daniel; Pizarro, Felipe; Zylberberg, Alejandro; Quezada, Felipe
    Object. Posterolateral spinal fusions are performed to treat different spinal disorders. Autograft continues to be the gold standard; it is, however, associated with donor site morbidity and limited sources. Allograft has been used, but has been reported to result in lower fusion rates. Demineralized bone matrix (DBM) has also been used and reportedly increases the fusion rate in a variety of critical defect models. Different forms of DBM are available, not all have been independently studied. To evaluate the effect of a xenogenic DBM added to allograft on the fusion rate of posterolateral lumbar spine arthrodesis the authors designed an experimental study comparing posterolateral fusion rate using autograft, allograft, and allograft plus a xenogenic DBM in a validated animal model.
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    Cultured autologous bone marrow stem cells inhibit bony fusion in a rabbit model of posterolateral lumbar fusion with autologous bone graft
    (ELSEVIER SCI LTD, 2010) Urrutia, Julio; Mery, Pablo; Martinez, Rafael; Pizarro, Felipe; Apablaza, Daniel; Mardones, Rodrigo
    Mesenchymal stem cells (MSCs) have been isolated from various tissues and expanded in culture. MSCs add osteogenic potential to ceramic scaffolds when used together. A spinal fusion rabbit model was used to evaluate whether a pellet of cultured, autologous bone marrow MSCs (BMSCs) with osteogenic differentiation could increase the fusion rate when co-grafted with an autologus bone graft compared to autograft alone. Thirty rabbits were randomly assigned to two groups. Group I received bone autograft alone and Group 2 received bone autograft plus a pellet of cultured and differentiated BMSCs. Group 2 rabbits had a bone marrow puncture, after which the BMSC were cultured and osteoblastic differentiation was induced. BMSC cultures were obtained from 12 of 15 rabbits. The 27 rabbits underwent a bilateral, L4-L5 intertransverse fusion with an autograft and in Group 2 rabbits a pellet of differentiated BMSCs was added to the autograft. In Group 1, the fusion rate was 53% (8 of 15 rabbits) and ill Group 2 the fusion rate was 0% (p < 0.05). Adding differentiated BMSCs in a pellet without a scaffold not only failed to increase fusion rate, but completely inhibited bony growth. (C) 2009 Elsevier Ltd. All rights reserved.