Expandable Shape-Memory Polymers for Suture Anchors

描述（由申请人提供）：本项目将开发一种能够动态扩张的形状记忆聚合物缝线锚，专为骨量密度差的患者设计。带线锚钉是螺钉或楔形器械，固定在骨内，用于将分离的肌腱固定在骨上。12周后，肌腱应达到自然的生物固定，被认为是成功修复。肩袖修复术是最常见的外科手术，涉及缝线锚钉，每年进行超过75，000次。修复中的一般挑战和限制是必须放置锚的大量软松质骨，这使得锚钉更容易移位、松动/隧道扩大和拔出。此外，越来越多的60岁以上的患者正在接受肩袖修复并患有骨质疏松症。骨密度差的患者存在器械失效的高风险，因为骨密度与带线锚钉的固定强度相关。申报的形状记忆聚合物缝线锚将（i）设计为使其扩张力与骨的性能极限相匹配，以优化固定强度，以及（ii）能够动态适应隧道加宽，以确保愈合期间的稳定固定。这项工作的广泛影响将向市场引入一种新型的形状记忆生物材料，并可能彻底改变肩袖修复，并涉及所有涉及缝线锚钉的手术。SBIR第I阶段设计不仅为形状记忆聚合物缝线锚提供可行性，还生成进入第II阶段的基本材料信息。本阶段I的两个主要目的是（i）将聚合物结构和器械设计与径向恢复力联系起来，同时证明生物相容性，以及（ii）提供与当前器械相比的充分拔出数据，并说明聚合物可适应隧道加宽。第一个目标将主要包括材料合成，网络和形状记忆表征，以及细胞相容性测试。第二个目的是利用猪骨模型对市售器械和形状记忆聚合物原型进行单调和循环拔出测试并进行比较。主要研究团队将由MedShape Solutions的首席研究员Christopher Yakacki博士组成，他在形状记忆聚合物的合成和表征方面具有经验;来自格鲁吉亚理工学院的材料科学家Ken Gall博士，他是专门研究形状记忆材料的全职教授;以及整形外科医生Reed Bartz MD，他是关节镜肩关节修复专家。随着年龄的增长，越来越多的人口保持身体活动。这个项目是有关这一比例的人经历了一个衰弱的伤害，如肩袖撕裂。该项目将提供一种方法来恢复功能，以减少手术失败的发生，并提高他们的生活质量。

DESCRIPTION (provided by applicant): This project will develop a shape-memory polymer suture anchor capable of dynamic expansion and is specifically designed for patients with poor bone mass density. Suture anchors are screw or wedge-like devices that fasten into the bone and are used to secure a detached tendon to the bone. After a 12-week period, the tendon should achieve natural biological fixation to be considered successfully repaired. Rotator cuff repair is the most common surgical procedure involving suture anchors and are performed over 75,000 times annually. A general challenge and constraint in repair is the large amount soft cancellous bone where the anchor must be placed, which makes the anchors more susceptible to migration, loosening/tunnel widening, and pullout. Furthermore, a growing number of patients over 60 years of age are receiving rotator cuff repairs and suffer from osteoporosis. Patients with poor bone mass density are highly at risk to device failure as bone density have been correlated to the fixation strength of suture anchors. The proposed shape-memory polymer suture anchor will be (i) designed to match its expansion forces to the bone's performance limits to optimize fixation strength and (ii) be able to dynamically adapt to tunnel widening to ensure stable fixation during the healing period. The broad impact of this work will introduce a new type of shape-memory biomaterial into the market as well as potentially revolutionize rotator cuff repair and reach into all procedures involving suture anchors. The SBIR Phase I is designed to not only provide feasibility to the shape-memory polymer suture anchor, but also to generate fundamental material information to move into Phase II. The two main aims of this Phase I are (i) link the polymer structure and device design to the radial recovery force, while proving biocompatibility and (ii) provide sufficient pullout data compared to current devices and illustrate the polymer can adapt to tunnel widening. The first aim will primarily consist of material synthesis, network and shape-memory characterization, and cytocompatibility testing. The second aim will make use of a porcine bone model to perform and compare monotonic and cyclic pullout testing of commercially available devices and shape-memory polymer prototypes. The primary research team will consist of a principal investigator from MedShape Solutions, Christopher Yakacki PhD, who has experience in synthesis and characterization of shape-memory polymers; a materials scientists from The Georgia Institute of Technology, Ken Gall PhD, who is a full professor specializing in shape-memory materials; and an orthopedic surgeon, Reed Bartz MD, who is an expert in arthroscopic shoulder repair. Project Narrative A growing percentage of the population is remaining physically active as they age. This project is relevant to this percentage of people that experience a debilitating injury such as a rotator cuff tear. This project will provide a means to restore function to their shoulders with less occurrence of surgical failure and increase their quality of life.