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展的形状记忆聚合物缝合锚，专为骨密度低的患者设计。缝合锚钉是螺钉或楔形装置，固定在骨头上，用于将分离的肌腱固定在骨头上。12周后，肌腱应达到自然生物固定，视为成功修复。肩袖修复是最常见的外科手术，涉及缝合锚钉，每年进行超过75,000次。修复中一个普遍的挑战和限制是锚钉必须放置大量柔软的松质骨，这使得锚钉更容易移动、松动/隧道拓宽和拔出。此外，越来越多的60岁以上的患者接受肩袖修复并患有骨质疏松症。骨密度低的患者发生装置失效的风险高，因为骨密度与缝合锚钉的固定强度有关。所提出的形状记忆聚合物缝合锚将(i)设计为使其膨胀力与骨的性能极限相匹配，以优化固定强度，（ii）能够动态适应隧道拓宽，以确保在愈合期间稳定固定。这项工作的广泛影响将为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和涉及缝合锚钉的所有手术。SBIR第一阶段的设计不仅为形状记忆聚合物缝合锚提供可行性，而且还为进入第二阶段提供基础材料信息。第一阶段的两个主要目标是：(I)将聚合物结构和设备设计与径向回收力联系起来，同时证明生物相容性；（ii）与现有设备相比，提供足够的拔出数据，并说明聚合物可以适应隧道加宽。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。第二个目标是利用猪骨模型来执行和比较商用设备和形状记忆聚合物原型的单调和循环拔出测试。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丰富的经验；乔治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正教授；以及骨科医生里德·巴茨医学博士，他是关节镜下肩关节修复的专家。随着年龄的增长，越来越多的人仍然保持体育锻炼。这个项目与那些经历过像肩袖撕裂这样的损伤的人有关。这个项目将提供一种方法来恢复他们的肩部功能，减少手术失败的发生，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.