Soft-Tissue Orthopedic Fixation with Shape Memory Polymers

描述(申请人提供)：该探索性研究项目旨在开发和验证基于新兴形状记忆聚合物的软组织矫形固定装置。这项拟议的工作重点是创造用于前交叉韧带(ACL)膝关节重建的自部署形状记忆聚合物固定装置，这项手术每年花费美国约20亿美元。前交叉韧带重建是运动医学中常见和关键的手术，为骨科提供了理想的实验床形状记忆聚合物。目前的软组织固定设备是基于非活性聚合物或金属螺丝钉，通过高扭矩插入或夹紧过程中产生的力将肌腱固定在骨隧道中。形状记忆聚合物提供了一种更简单、更强大、更通用的方法来促进肌腱移植物和骨隧道之间的固定和均匀愈合，从而为微创软组织矫形固定提供了潜在的优越解决方案。本质上，形状记忆聚合物设备可以以紧凑的状态被输送到人体内，并被编程为一旦达到规定的温度(例如，体温或略高的温度)就自动展开并施加力量。本研究有两个具体目的：(1)评价几种候选形状记忆聚合物材料的热机械恢复性能和生物相容性；(2)评价几种原型形状记忆聚合物前交叉韧带锚固材料在体外牛模型中的效果。这项工作将产生关于候选形状记忆聚合物的热机械行为和生物相容性的基础知识，以及关于形状记忆聚合物矫形固定装置的体外性能的基础知识。这一结果将为基于形状记忆聚合物的软组织矫形固定装置的更大的可靠性和体内疗效奠定基础。这项工作将由一名材料科学家/机械工程师(Gall)、一名生物学家(Boyan)和一名运动医学医生(Bartz)密切合作完成。由形状记忆聚合物制成的生物医疗设备在医疗设备中具有巨大的潜力，从整形外科固定设备(在拟议的工作中概述)到心血管支架和智能缝合线。从拟议的工作中收集的知识应该在这些医学领域中的几个领域产生广泛的影响。

DESCRIPTION (provided by applicant): This exploratory research project aims to develop and validate soft tissue orthopedic fixation devices based on emerging shape memory polymers. The proposed work focuses specifically on the creation of self-deploying shape memory polymer fixation devices for Anterior Cruciate Ligament (ACL) knee reconstruction, a surgery costing the United States approximately 2 billion dollars annually. ACL reconstruction is a common and critical surgery in sports medicine, and provides an ideal testbed shape memory polymers in orthopedics. Current soft tissue fixation devices are based on inactive polymer or metal screws used to fix a tendon in a bony tunnel through forces generated during high-torque insertion or clamping. Shape memory polymers provide a potentially superior solution to minimally invasive soft tissue orthopedic fixation by providing a simpler, stronger, and more versatile method to promote fixation and uniform healing between tendon grafts and a bony tunnel. Essentially, a shape memory polymer device can be delivered into the body in a compacted state and programmed to self- deploy and impart forces once it reaches a prescribed temperature (e.g. the body temperature or a slightly elevated temperature). The research contains two specific aims: (1) evaluate the thermo-mechanical recovery properties and biocompatibility of several candidate shape memory polymer materials, and (2) evaluate the efficacy of several prototype shape memory polymer ACL anchors in an in-vitro bovine model. The present work will result in fundamental knowledge regarding the thermo-mechanical behavior and biocompatibility of candidate shape memory polymers and fundamental knowledge on the in-vitro performance of shape memory polymer orthopedic fixation devices. The results will provide proof of concept and set the stage for a larger reliability and in-vivo efficacy effort on shape memory polymer based soft-tissue orthopedic fixation devices. The work will be performed as a close collaboration between a materials scientist/mechanical engineer (Gall), a biologist (Boyan), and a sports medicine doctor (Bartz). Biomedical devices fabricated from shape memory polymers have significant potential in medical devices ranging from orthopedic fixation devices (outlined in the proposed work) to cardiovascular stents and smart sutures. The knowledge gleaned from the proposed work should have broad impact in several of these medical fields.