Shape memory bone and soft tissue fixations

在我们当前研究的基础上，我们将探索由生物惰性和生物可吸收形状记忆聚合物（SMP）制成的增强型骨与骨和软组织与骨固定装置。当受到高于其玻璃化转变温度的适当刺激（通常是加热）时，它们恢复或部分恢复初始形状。SMP将通过加工操作进行结构化，以获得受控的分子取向，其恢复驱动形状逆转。该研究将与医疗器械公司Innovate Orthopaedics和Fortius Clinic的临床医生密切合作进行。拟议的研究将解决：（i）主要细分市场中未满足的特定临床需求，（包括肩膝韧带损伤、腕关节撕裂和舟状骨骨折）;（ii）治疗特定患者亚组以实现减少的总体恢复时间，包括更快的“恢复功能”时间，例如，50岁以上的老年人更容易受到创伤和退行性损伤;肥胖水平的上升是关节炎和关节损伤的风险因素;高性能运动员或军事人员/体力劳动者遭受运动或与工作有关的创伤;在大多数情况下，这类损伤带来了巨大的社会经济成本;（iii）克服了现有产品中已知的缺陷（例如金属加压螺钉松动）;（iv）增强了外科医生的功能，有可能缩短手术时间和简化手术，并大大减少库存。在我们的研究中：（i）SMP将被配制用于特定的应用，通过包括增塑剂以控制回复起始温度，和其他添加剂;（ii）SMP将通过（a）固相加工以获得受控的分子取向，其回复驱动形状回复，（B）通过精密注射成型，和（c）通过使用一系列技术的混合加工来结构化，所述技术包括：SMP芯的包覆成型;回复成型;将SMP恢复为模制的末端特征;开发新的几何形状以减少对组织的热传递; 3D打印两种材料用于固相处理。(ii)T体液触发形状恢复（iii）在临床相关时间尺度内的受控逆转-根据应用快速或慢速，使用受控逆转触发温度，包括体温-和逆转程度;（iv）生物吸收速率与干扰力和从骨中拔出力之间的平衡（利兹大学设施）;（iii）形状记忆行为在适应骨和固定孔质量变化中的价值;（v）骨特性/骨生成的匹配，包括纳米羟基磷灰石和我们实验室正在开发的抗炎剂的掺入;（五）建模合作伙伴角色：临床医生- a）定义特定适应症的临床挑战/要求，特别是舟状骨加压螺钉和软组织固定，包括ACL和肩袖修复; B）输入固定器械的设计，以及c）帮助消除临床采用的障碍;行业-评估a）市场规模，B）工艺经济性，c）市场途径，d）器械设计监管-我们将通过我们的Mede创新中心与MHRA和BSI合作。

Building on our current research, we will explore enhanced bone to bone and soft tissue to bone fixation devices made from bionert and bioresorbable shape memory polymers (SMP). These recover or partially recover an initial shape when subject to an appropriate stimulus (usually heating) above their glass transition temperature. SMPs will be structured by processing operations, to obtain controlled molecular orientation, whose recovery drives shape reversion. The research will be undertaken in close collaboration with Innovate Orthopaedics, a medical device company and Clinicians from the Fortius Clinic.The proposed research will address: (i) specific unmet clinical needs in major market segments, (including shoulder and knee ligament injuries, meniscal tears and scaphoid fractures); (ii) treatment of specific patient subgroups to achieve a reduced overall recovery time, including a faster 'return to function' time, e.g. older people - over 50's are more susceptible to traumatic and degenerative injuries; rising levels of obesity are a risk factor in arthritis and meniscal injury; high performance athletes, or military personnel/ manual workers suffer sports or job-related trauma; for most cases, such injuries bring a significant socio-economic cost; (iii) overcoming known deficiencies in existing products (e.g. loosening metal compression screws); (iv) enhanced functionality for surgeons, with the potential for shorter theatre times and simplified procedures, and significantly reduced inventories. In our research:(i) SMPs will be formulated for specific applications, by including plasticisers to control reversion onset temperature, and other additives;(ii) SMPs will be structured by (a) solid phase processing, to obtain controlled molecular orientation, whose recovery drives shape reversion, (b) by precision injection moulding, and (c) by hybrid processing using a range of techniques including: overmoulding of SMP cores; reversion moulding; reverting SMPs into moulded end features; developing novel geometries to reduce heat transfer to tissue; 3-d printing of two materials for solid phase processing.;(ii) Triggering of shape recovery by body T fluid (saline 37C); micro resistance heating probe; a hybridroute - trigger start of recovery by heating probe, with prolonged body T reversion by plasticisers; local ultrasound heating(iii) controlled reversion in clinically relevant timescales - fast or slow according to application, using controlled reversion triggering temperature, including body temperature - and degree of reversion;(iv) the balance between bioresorption rate and interference force and pull out force from bone (Leeds University facilities);(iii) the value of shape memory behaviour in accommodating variations in bone and fixing hole quality;(v) match of bone properties/ osteogenesis including incorporation of nano hydroxyapatite and antiinflammatories being developed in our labs;(v) modelling (finite element analysis) of stresses in SMP fixations to inform optimal design.Partner Roles:Clinicians - a) define Clinical challenges/ requirements for specific indications, especially scaphoidcompression screws and soft tissue fixations, including ACL and rotator cuff repair; b) input to designof fixation devices and c) help remove barriers to clinical adoption;Industry - evaluate a) market size, b) process economics, c) routes to market, d) device designsRegulatory - we will engage with MHRA and BSI via our MeDe Innovation Centre.