Soft-Tissue Orthopedic Fixation with Shape Memory Polymers

描述（由申请人提供）：本探索性研究项目旨在开发和确认基于新兴形状记忆聚合物的软组织骨科固定器械。拟议的工作重点是创建用于前交叉韧带（ACL）膝关节重建的自部署形状记忆聚合物固定装置，该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而关键的手术，为形状记忆聚合物在骨科的应用提供了理想的实验平台。当前的软组织固定装置基于用于通过在高扭矩插入或夹紧期间产生的力将肌腱固定在骨隧道中的非活性聚合物或金属螺钉。形状记忆聚合物通过提供更简单、更坚固、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，为微创软组织骨科固定提供了潜在的上级解决方案。基本上，形状记忆聚合物装置可以以压实状态递送到体内，并且一旦达到规定温度（例如，体温或稍微升高的温度）就被编程为自展开并施加力。本研究包含两个特定目的：（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，以及（2）评价几种原型形状记忆聚合物ACL锚钉在体外牛模型中的有效性。目前的工作将导致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和形状记忆聚合物骨科固定器械的体外性能的基础知识。这些结果将提供概念验证，并为基于形状记忆聚合物的软组织骨科固定器械的更大可靠性和体内有效性奠定基础。这项工作将作为材料科学家/机械工程师（Gall），生物学家（Boyan）和运动医学医生（Bartz）之间的密切合作进行。由形状记忆聚合物制成的生物医疗器械在医疗器械中具有巨大的潜力，从骨科固定器械（在拟议的工作中概述）到心血管支架和智能缝线。从拟议的工作中收集到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.