INFORCING RESORBABLE BUFFERED INTERNAL FIXATION DEVICES

强化可吸收缓冲内固定装置

基本信息

批准号：
6171785
负责人：
DEBRA J TRANTOLO
金额：
$ 38.69万
依托单位：
CAMBRIDGE SCIENTIFIC, INC.
依托单位国家：
美国
项目类别：
财政年份：
1997
资助国家：
美国
起止时间：
1997-08-16 至 2002-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6171785
关键词：
biomaterial compatibility biomaterial development /preparation biomechanics bone prosthesis calcium phosphate fracture fixation glycolates histology hydroxyapatites laboratory rabbit lactates medical implant science orthopedics polymers radiography sheep tissue engineering

项目摘要

The inflammatory response associated with the use of resorbable orthopedic fixation devices can be eliminated by incorporating a long acting buffer into a poly(lactic-co-glycolic acid), "PGLA", fixation device which will neutralize acidic degradation products. The inclusion of the osteoconductive calcium phosphate, hydroxyapatite (HA), as a buffer in a PLOA-based fixture effectively moderates the rate of pH decline as the fixture degrades. HA promotes bony ingrowth, obviates loosening of the fixture, and acts as a buffer. It is the objective of this project to stabilize the mechanical characteristics of this fixture via the use of self-reinforcing fibers. The concept of self- reinforcement of the fixture implies the formation of a composite material comprised of reinforcing fibers of a composition similar in chemical structure to either the polymeric PGLA component of the fixture or the buffering calcium phosphate component of the fixture. The Phase II experimental design will focus on preclinical in vivo development of two functional reinforced fixture candidates, based on the requirement of "substantial equivalence" to obtain FDA 5l0k approval. Structural performance in both small (rabbit) and large (sheep) animal models will be characterized. The small animal model will be used to screen two selected fiber candidates, whereas the large animal model will be used to test the final fixture configuration. The main goal of the rabbit experiments will be to develop the temporal history of the osteotomy healing in relation to fixture degradation. The final fixture will be employed in the sheep model with the objective of demonstrating functionality equivalent to commercially available fixation devices. PROPOSED COMMERCIAL APPLICATIONS: Of the more than 1.1 million fractures in the U.S. each year, greater than 470,000 require internal fixation devices to stabilize the fracture during the healing process. While there is significant clinical demand for resorbable devices, available products have not been widely adopted because of inflammatory responses to degradation. Our studies show that a buffered resorbable fixation device may ameliorate these responses. Development of the necessary strength will address the clinical demand for acceptable resorbable orthopedic materials.

与使用可再吸收的骨科固定装置相关的炎症反应可以通过将长效缓冲剂掺入聚(乳酸-乙醇酸)“PGLA”固定装置中来消除，该固定装置将中和酸性降解产物。在基于 PLOA 的固定装置中加入骨传导性磷酸钙、羟基磷灰石 (HA) 作为缓冲剂，可有效减缓固定装置降解时 pH 值下降的速度。 HA 促进骨向内生长，避免固定装置松动，并起到缓冲作用。该项目的目标是通过使用自增强纤维来稳定该夹具的机械特性。固定装置的自增强概念意味着形成由增强纤维组成的复合材料，该增强纤维的化学结构与固定装置的聚合PGLA组分或固定装置的缓冲磷酸钙组分相似。 II 期实验设计将侧重于两种功能性增强夹具候选物的临床前体内开发，基于“实质等效”的要求以获得 FDA 5l0k 批准。将表征小型（兔子）和大型（羊）动物模型的结构性能。小动物模型将用于筛选两种选定的候选光纤，而大型动物模型将用于测试最终的夹具配置。兔子实验的主要目标是开发与固定装置退化相关的截骨愈合的时间历史。最终的固定装置将用于绵羊模型，目的是展示与市售固定装置相当的功能。拟议的商业应用：在美国每年超过 110 万例骨折中，超过 470,000 例在愈合过程中需要内固定装置来稳定骨折。虽然可吸收装置的临床需求很大，但由于降解引起的炎症反应，现有产品尚未得到广泛采用。我们的研究表明，缓冲可吸收固定装置可以改善这些反应。开发必要的强度将满足可接受的可吸收矫形材料的临床需求。