Noninvasive assessment of in vivo tissue loads to enhance the treatment of gait disorders

摘要 这项研究的长期目标是使用活体肌肉-肌腱力量测量来增强 脑性瘫痪患者步态障碍的临床治疗。我们最近已经证明， 肌腱振动的频率取决于施加的应力。这种现象是 类似于在吉他弦上看到的依赖张力的振动。振动频率反映速度 横波或横波在这个位置传播。因此，监测横波速度可能是可行的。 在肌腱中作为组织负载的代理。这项研究将调查测量和解释 人体肌腱的剪切波速度。 最初的两个目的是为了调查以下关系的有效性和稳健性 横波速度和肌腱载荷。皮肤安装式张力计将被设计成感应和 跟踪传播微米量级的横波。将对身体脚踝标本进行测试 在目标1中，机器人步态模拟器将驱动外部脚和内部肌腱加载，以模仿人类 走路。肌腱张力和波速将被同时监测。人类的受试者将是 在AIM 2进行了测试。放置在浅膝关节和脚踝肌腱上的张力计将监测波形 受试者进行等长和等速运动时的速度。来自AIMS 1和2的数据将用于 研究特定主题和特定肌腱的几何形状如何调节肌腱之间的关系 波速和载荷。最后两个目标将使用张力计测量横波速度 行走时的腿部浅肌腱。通常情况下，发育中的儿童将在目标3中接受测试，以确定 步态周期中波速模式的标准数据库。患有CP的个人表现为 马蹄(脚趾行走)或蹲伏(屈膝)将在AIM 4进行测试。肌腱波速测量将 是在受试者接受标准临床步态分析时获得的。我们将探索临床 通过在剪切波速数据、关节动力学、肌电信号之间执行直接比较来实现实用性 以及基于传统步态分析的临床解释。 这项研究的预期结果是一种开创性的方法来评估活体肌肉肌腱 正常步态和病态步态的负荷量。成功完成这些目标可能会导致 加强步态障碍的诊断和结果评估。

Abstract The long-term goal of this research is to use in vivo muscle-tendon force measurements to enhance the clinical treatment of gait disorders in individuals with cerebral palsy (CP). We have recently shown that the frequency at which a tendon vibrates is dependent on the applied stress. This phenomenon is similar to the tension-dependent vibration seen in guitar strings. Vibration frequency reflects the speed at which transverse, or shear, waves propagate. Hence, it may be feasible to monitor shear wave speed in tendon as a proxy for tissue loading. This study will investigate the potential to measure and interpret shear wave speeds in human tendons. The initial two aims are designed to investigate the validity and robustness of the relationship between shear wave speed and tendon loading. Skin-mounted tensiometers will be designed that induce and track propagating shear waves of micron-scale amplitude. Cadaveric ankle-foot specimens will be tested in aim 1. A robotic gait simulator will drive external foot and internal tendon loading to emulate human walking. Tendon tensions and wave speeds will be simultaneously monitored. Human subjects will be tested in Aim 2. Tensiometers positioned over superficial knee and ankle tendons will monitor wave speeds while subjects perform isometric and isokinetic exertions. Data from aims 1 and 2 will be used to investigate how subject- and tendon-specific geometry can modulate the relationship between tendon wave speed and load. The final two aims will use tensiometers to measure shear wave speeds in the superficial leg tendons during walking. Typically developing children will be tested in Aim 3 to establish a normative database of wave speed patterns over a gait cycle. Individuals with CP who exhibit either equinus (toe-walking) or crouch (flexed knee) will be tested in Aim 4. Tendon wave speed measures will be obtained while subjects are undergoing a standard clinical gait analysis. We will explore clinical utility by performing direct comparisons between shear wave speed data, joint kinetics, EMG signals and clinical interpretations based on traditional gait analysis. The anticipated outcome of this study is a ground-breaking approach to assess in vivo muscle-tendon loads during both normal and pathological gait. Successful completion of the aims could lead to enhanced diagnosis and outcomes assessment of gait disorders.