Edward Ahn - Academia.edu (original) (raw)
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Centre National de la Recherche Scientifique / French National Centre for Scientific Research
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Papers by Edward Ahn
La presente invention concerne des compositions utiles pour regenerer un tissu conjonctif, en par... more La presente invention concerne des compositions utiles pour regenerer un tissu conjonctif, en particulier un os. Les compositions comprennent une matrice continue formee a partir d'un polypeptide reticule a un second polymere, des particules de materiau poreux osteoconducteur etant dispersees dans la matrice continue. La composition peut etre fournie sous forme deshydratee. L'invention concerne en outre des procedes de preparation de la composition sous une formule utile en clinique, des procedes d'utilisation de la composition pour regenerer des os et des kits contenant la composition.
L'invention concerne des procedes permettant d'effectuer la synthese de phosphates trical... more L'invention concerne des procedes permettant d'effectuer la synthese de phosphates tricalciques, ainsi qu'une serie de parametres de reaction specifiques pouvant etre regles afin de personnaliser, de maniere specifique, des proprietes dans le precipite precurseur de phosphate de tricalcique. L'invention concerne egalement des compositions particulaires de phosphate tricalcique possedant une taille moyenne de cristal d'environ 250 nm ou moins. Les compositions de l'invention peuvent etre utilisees comme implants prothetiques et revetement d'implants prothetiques.
Minimally Invasive Spine Surgery, 2009
Osteoporosis results in the thinning of the cortical shell and trabecular struts of the bones suc... more Osteoporosis results in the thinning of the cortical shell and trabecular struts of the bones such that the loads of normal daily activities can result in fractures.In the case of osteoporosis of the vertebrae, vertebral compression fractures (VCF) can occur spontaneously or as the result of a low-energy trauma, resulting in chronic pain and reduced mobility [1]. If left untreated,
Journal of the American Ceramic Society, 2005
Introduction The need for regeneration and repair of bone presents itself in a variety of clinica... more Introduction The need for regeneration and repair of bone presents itself in a variety of clinical situations. The current gold standard of treatment is autograft harvested from the iliac crest or local bone. Inherent disadvantages associated with the use of autogenous bone include limited supply, increased operating time and donor site morbidity. This study utilized a challenging model of posterolateral fusion to evaluate the in vivo response of an engineered collagen carrier combined with nano-structured hydroxyapatite (NanOss Bioactive 3D, Pioneer Surgical) compared to a collagen porous beta-tricalcium phosphate bone void filler (Vitoss BA, Orthovita). Materials and Methods A single level posterolateral fusion was performed in 72 adult rabbits at 6, 12 and 26 weeks (8 per group per time point). Group 1: nanOss Bioactive 3D + bone marrow aspirate (BMA) + autograft, Group 2: Vitoss BA + BMA and Group 3: Autograft + BMA were compared were compared using radiographic (X-ray and Micro-computed tomography (μCT), biomechanics (manual palpation and tensile testing at 12 and 26 weeks) and histology. Results Radiographic grading and μCT demonstrated progressive increases in radiopacity at the transverse processes and at the middle of the developing fusion for Groups 1 and 3. New bone formation was noted for Group 2 only at the transverse processes (not in the middle of the fusion site). In this challenging model, manual palpation revealed comparable fusion rates in Groups 1 and 3 (43% and 38%, respectively). None of the animals from Group 2 were fused by manual palpation. Group 3 outperformed Group 2 (P Discussion Posterolateral fusion models represent an extremely challenging biological site to evaluate bone graft materials and provide insight into clinical performance. Group 1 (nanOss Bioactive 3D + Autograft + BMA) performed well in the current model providing an osteoconductive scaffold that supported new bone formation on the transverse processes as well as in the middle of the fusion mass and that remodeled with time based on all endpoints. The graft materials had yet to completely resorb by 26 weeks in the current model. Group 2 performed well on the transverse processes in terms of new bone formation however new bone in the middle of the fusion mass was negligible at 6, 12, and 26 weeks. Group 3 (Autograft + BMA) performed well with new bone formation and remodeling on the transverse process and in the middle of the fusion mass as well as is consistently reported with this model.
La presente invention concerne des compositions utiles pour regenerer un tissu conjonctif, en par... more La presente invention concerne des compositions utiles pour regenerer un tissu conjonctif, en particulier un os. Les compositions comprennent une matrice continue formee a partir d'un polypeptide reticule a un second polymere, des particules de materiau poreux osteoconducteur etant dispersees dans la matrice continue. La composition peut etre fournie sous forme deshydratee. L'invention concerne en outre des procedes de preparation de la composition sous une formule utile en clinique, des procedes d'utilisation de la composition pour regenerer des os et des kits contenant la composition.
L'invention concerne des procedes permettant d'effectuer la synthese de phosphates trical... more L'invention concerne des procedes permettant d'effectuer la synthese de phosphates tricalciques, ainsi qu'une serie de parametres de reaction specifiques pouvant etre regles afin de personnaliser, de maniere specifique, des proprietes dans le precipite precurseur de phosphate de tricalcique. L'invention concerne egalement des compositions particulaires de phosphate tricalcique possedant une taille moyenne de cristal d'environ 250 nm ou moins. Les compositions de l'invention peuvent etre utilisees comme implants prothetiques et revetement d'implants prothetiques.
Minimally Invasive Spine Surgery, 2009
Osteoporosis results in the thinning of the cortical shell and trabecular struts of the bones suc... more Osteoporosis results in the thinning of the cortical shell and trabecular struts of the bones such that the loads of normal daily activities can result in fractures.In the case of osteoporosis of the vertebrae, vertebral compression fractures (VCF) can occur spontaneously or as the result of a low-energy trauma, resulting in chronic pain and reduced mobility [1]. If left untreated,
Journal of the American Ceramic Society, 2005
Introduction The need for regeneration and repair of bone presents itself in a variety of clinica... more Introduction The need for regeneration and repair of bone presents itself in a variety of clinical situations. The current gold standard of treatment is autograft harvested from the iliac crest or local bone. Inherent disadvantages associated with the use of autogenous bone include limited supply, increased operating time and donor site morbidity. This study utilized a challenging model of posterolateral fusion to evaluate the in vivo response of an engineered collagen carrier combined with nano-structured hydroxyapatite (NanOss Bioactive 3D, Pioneer Surgical) compared to a collagen porous beta-tricalcium phosphate bone void filler (Vitoss BA, Orthovita). Materials and Methods A single level posterolateral fusion was performed in 72 adult rabbits at 6, 12 and 26 weeks (8 per group per time point). Group 1: nanOss Bioactive 3D + bone marrow aspirate (BMA) + autograft, Group 2: Vitoss BA + BMA and Group 3: Autograft + BMA were compared were compared using radiographic (X-ray and Micro-computed tomography (μCT), biomechanics (manual palpation and tensile testing at 12 and 26 weeks) and histology. Results Radiographic grading and μCT demonstrated progressive increases in radiopacity at the transverse processes and at the middle of the developing fusion for Groups 1 and 3. New bone formation was noted for Group 2 only at the transverse processes (not in the middle of the fusion site). In this challenging model, manual palpation revealed comparable fusion rates in Groups 1 and 3 (43% and 38%, respectively). None of the animals from Group 2 were fused by manual palpation. Group 3 outperformed Group 2 (P Discussion Posterolateral fusion models represent an extremely challenging biological site to evaluate bone graft materials and provide insight into clinical performance. Group 1 (nanOss Bioactive 3D + Autograft + BMA) performed well in the current model providing an osteoconductive scaffold that supported new bone formation on the transverse processes as well as in the middle of the fusion mass and that remodeled with time based on all endpoints. The graft materials had yet to completely resorb by 26 weeks in the current model. Group 2 performed well on the transverse processes in terms of new bone formation however new bone in the middle of the fusion mass was negligible at 6, 12, and 26 weeks. Group 3 (Autograft + BMA) performed well with new bone formation and remodeling on the transverse process and in the middle of the fusion mass as well as is consistently reported with this model.