STRENGTH AND RESORPTION OF BIODEGRADABLE SKULL IMPLANTS

可生物降解颅骨植入物的强度和吸收

• 批准号: 6497922
• 负责人: David Dean
• 金额: $ 37.46万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-02-01 至 2005-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6497922
• 关键词: angiogenesis; biodegradable product; biomaterial compatibility; bone prosthesis; calcium phosphate; computed axial tomography; dicarboxylate; dogs; implant; laboratory rabbit; magnetic resonance imaging; medical implant science; osteogenesis; polypropylenes; skull; tissue engineering

DESCRIPTION: (adapted from applicant's abstract) Large skull defects arise frequently following neurosurgery and craniofacial reconstructive surgery for trauma, cancer resection, and congenital deformity. Concerns over revascularization, aesthetics, and protective strength of the patient's own bone or artificial plating are magnified by the post-surgical need to protect the brain from infection and trauma. Tissue engineered bone replacements have been shown to ossify small skeletal defects with potential utility in fracture repair, but currently, these materials do not effectively address skull defects large enough to require graft or prosthetic augmentation. The primary surgical option, autogenous grafts, extend the patient's deficits to a new site and may resorb or become infected. Non-tissue engineered implanted materials interrupt vasculature between the dura, bone and scalp, and risk infection or extrusion. Limited means of diagnostic assay lead to neurocranial repair problems presenting initially as a failure requiring surgery. Tissue engineering neurocranial prosthetics could overcome these limitations if shown to maintain their shape and protective strength while bone migrates from the host into the implant's center. The investigators propose an animal model that extends current work on poly(propylene fumarate)/beta-tricalcium phosphate (PPF/beta-TCP) photopolymer critical size implants to truly large size neurocranial defects. Specifically, the following three hypotheses will be tested: 1) Control peri-implant morphology, resorption environment, and strength concomitant to upward scaling of implant size to a level clinically useful for neurocranial repair (i.e., longest dimension form 1.5 to 4 cm); 2) Use standard clinical MR and CT to track prosthetic vascular ingrowth and ossification; and 3) Use composite solid/foam PPF/beta-TCP prosthetics, micro-machined with channels that promote vascular ingrowth through the solid core without loss of strength. To address these hypotheses, the investigators propose to determine the optimal design for PPF/beta-TCP composite implants seeded with bone marrow's osteoprogenitor cells and growth factors. They will collect in vitro strength before and during PPF/beta-TCP degradation, in vivo ossification and vascular ingrowth, and explant ex vivo strength and histology data.

描述：（改编自申请人的摘要）出现大的颅骨缺损 经常在神经外科和颅面重建手术之后 外伤、癌症切除和先天性畸形。担忧 血运重建、美观和患者自身的保护强度 骨或人造板因术后需要保护而被放大 大脑免受感染和创伤。组织工程骨替代物具有 已被证明可以使小的骨骼缺陷骨化，并在骨折中具有潜在的用途 修复，但目前这些材料并不能有效解决颅骨缺损 大到足以需要移植或假体增强。初级手术 选择自体移植，将患者的缺陷扩展到新部位，并且可能 吸收或被感染。非组织工程植入材料中断 硬脑膜、骨骼和头皮之间的脉管系统，存在感染或挤压的风险。 诊断测定手段有限导致神经颅修复问题 最初表现为需要手术的失败。组织工程 如果神经颅假体被证明可以克服这些限制 当骨骼从宿主迁移到体内时它们的形状和保护强度 种植体的中心。研究人员提出了一种动物模型 聚（富马酸丙烯酯）/β-磷酸三钙的当前工作 (PPF/beta-TCP) 光聚合物临界尺寸植入物达到真正的大尺寸 神经颅骨缺陷。具体而言，将提出以下三个假设： 测试：1) 控制种植体周围形态、吸收环境，以及 强度伴随着种植体尺寸向上扩展至临床水平 可用于神经颅修复（即最长尺寸为 1.5 至 4 厘米）； 2） 使用标准临床 MR 和 CT 来跟踪假体血管向内生长和 骨化； 3) 使用复合实心/泡沫 PPF/beta-TCP 假肢， 微机械加工的通道可促进血管通过固体向内生长 核心不损失力量。为了解决这些假设，研究人员 建议确定 PPF/beta-TCP 复合植入物的最佳设计 接种了骨髓的骨祖细胞和生长因子。他们会 在体内 PPF/beta-TCP 降解之前和期间收集体外强度 骨化和血管向内生长，以及外植体离体强度和组织学 数据。