BIOMECHANICAL MODELING OF TENDON TRANSFER IN TETRAPLEGIA

描述(申请人提供)：颈脊髓损伤后恢复手功能的肌腱转移手术并不总是像预期的那样成功。这项研究试图开发更好的生物力学模型来预测四肢瘫痪后恢复侧方痉挛的腕长屈肌腱移位术(BR-FPL)的结果。PI假设，由于术后肌肉适应和肘关节和腕伸肌无力，移植的BR的有效性受到损害。这项研究的目的是描述移植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相关的损害。 目标1将定义BR-FPL转移产生横向夹紧力的最大潜力。移植的名义模型将描述临床理想，即移植的肌肉具有正常的力量，并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在有过转移的受试者身上测量到的实际夹紧力。 目标2将确定手术前的虚弱在多大程度上限制了武力生产。根据通过医学成像获得的BR横截面积以及肘关节和手腕伸展强度的术前评估，将为8-10名手术候选人开发个性化的BR-FPL肌腱转移模拟。这些模型应该比名义模型更好地预测夹紧力。 目标3将确定手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。预计移植的肌肉横截面积将减少，远端肌肉纤维带减少，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将测试在侧向挤压过程中完全激活转移的BR的能力。由于缺乏稳定关节所需的腕部和肘部伸展力量，最大自愿用力捏合时的肌电预计会小于最大抵抗屈肘时的肌电(BR的原始功能)。 这项工作将确定和描述导致手术结果令人失望的因素，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.