BIOMECHANICAL MODELING OF TENDON TRANSFER IN TETRAPLEGIA

描述（由申请人提供）：颈脊髓损伤后恢复手部功能的肌腱转移手术并不总是像预期的那样成功。本研究将尝试开发更好的生物力学模型，用于预测肱桡肌-拇长屈肌（Br-FPL）肌腱转移的结果，这是一种恢复四肢瘫痪后外侧夹伤的手术。PI假设由于术后肌肉适应性和肘关节和腕关节伸肌无力，转移的Br的有效性受损。本研究的目的是描述转移肌肉中发生的结构和功能变化，并更准确地模拟与手术改变的四肢瘫痪肢体相关的损伤。 目标1将定义Br-FPL转移产生侧向挤压力的最大潜力。转移的标称模型将表征临床理想，其中转移的肌肉具有正常的强度，并且可以最大限度地激活其新功能。以前的工作表明，这个模型将大大高估实际捏力测量的受试者谁有转移。 目标2将确定行动前的弱点在多大程度上限制部队的生产。将根据术前对Br横截面积的评估（通过医学成像获得）以及肘和腕伸展强度，为8-10名手术候选人开发Br-FPL肌腱转移的个性化模拟。这些模型应该比标称模型更好地预测夹紧力。 目标3将确定术后肌肉和纤维结构的变化。转移的Br将被重新成像，并将应用一种新的电生理技术。预计转移的肌肉将具有减小的横截面积并且缺乏肌纤维的远端带，并且包含这些差异的模型将导致对实际结果的更好预测。 目标4将测试在横向夹持期间完全激活转移的Br的能力。在最大自愿努力捏的EMG预计将小于EMG在最大阻力肘屈曲（Br的原始功能），部分原因是缺乏手腕和肘关节稳定所需的伸展力量。 这项工作将确定和表征导致令人失望的手术结果的因素，这种更好的理解将导致更好的治疗决策。

DESCRIPTION (provided by applicant): Tendon transfer surgeries to restore hand function after cervical spinal cord injury are not always as successful as expected. This study will attempt to develop better biomechanical models for predicting the outcome of the brachioradialis-to-flexor-pollicis-longus (Br-FPL) tendon transfer, a procedure that restores lateral pinch following tetraplegia. The PIs hypothesize that the effectiveness of the transferred Br is impaired because of post-operative muscle adaptations and weakness of elbow and wrist extensors. The goal of this study is to characterize the structural and functional changes that take place in transferred muscle, and to more accurately model the impairments associated with the surgically altered tetraplegic limb. Aim 1 will define the maximum potential of the Br-FPL transfer to produce lateral pinch force. A nominal model of the transfer will characterize the clinical ideal, in which the transferred muscle has normal strength and can be maximally activated for its new function. Previous work suggests that this model will substantially overestimate actual pinch forces measured in subjects who have had transfers. Aim 2 will determine the extent to which pre-operative weakness limits force production. Personalized simulations of Br-FPL tendon transfers will be developed for 8-10 surgical candidates based on preoperative assessments of Br cross-sectional area, obtained by medical imaging, and elbow and wrist extension strength. These models should predict pinch force better than the nominal model. Aim 3 will identify post-operative changes to muscle and fiber architecture. The transferred Br will be reimaged and a novel electrophysiological technique will be applied. It is expected that the transferred muscle will have reduced cross-sectional area and lack distal bands of muscle fibers, and that models incorporating these differences will lead to even better predictions of actual outcomes. Aim 4 will test the ability to fully activate the transferred Br during lateral pinch. EMG during maximum voluntary effort for pinch is expected to be less than EMG during maximum resisted elbow flexion (Br's original function), in part due to lack of wrist and elbow extension strength needed for joint stabilization. This work will identify and characterize factors responsible for disappointing surgical results, and this better understanding will lead to better treatment decisions.