Development and Persistence of Tissue-Level Musculoskeletal Deformity Following Brachial Plexus Birth Injury

项目摘要 臂丛产伤是一种围产期创伤性神经肌肉损伤， 终身手臂损伤。这些儿童的肌肉麻痹也会导致骨骼和关节的后果，包括 肩胛骨和肱骨的畸形生长。BPBI发生在快速肌肉骨骼 生长，但驱动这些持续畸形的肌肉和骨骼的平行产后相互作用不是 明白临床报告和初步工作表明，受伤后短收缩的肌肉可以改变 肩关节的机械载荷与宏观和微观结构水平上观察到的骨畸形一致。 还存在活动肢体功能改变，活动和承重范围减少;已知废用 改变组织生长和成熟。最后，其他条件下的神经损伤也直接影响骨骼生长， 对产后的直接影响尚不清楚。确定未来治疗的适当目标需要 了解与骨骼和肌肉发育改变相关的哪些因素对驾驶最关键 改变增长。几乎没有人知道底层骨骼变化的时间和进展， 肌肉结构或代谢后神经损伤发生在出生时，为临床提供基础 决策的我们的主要假设是，BPBI后的骨畸形主要是由 机械环境，来源于瘫痪肌肉的纵向生长受损和活动性改变 功能负荷在受伤后不久开始。我们将应用我们独特的啮齿动物和计算模型， BPBI探索神经损伤和肌肉挛缩的单独贡献，以实现互补 评估神经损伤、被动肌肉负荷和主动功能负荷的相对贡献 BPBI后骨畸形。我们将使用1）先前验证的大鼠肱动脉神经切除术模型 神经丛损伤和我们独特的改变负荷的离断模型; 2）一个综合的计算模型 确定BPBI后骨畸形的哪些具体特征主要由每种电位驱动 司机该R 01项目由一个具有骨科手术专业知识的多学科团队进行， 生物力学工程，具有很高的潜力，以阐明失神经支配的作用，在平行的发展， 出生后形成的骨骼和肌肉。我们创新的研究设计使我们能够分离出两种直接神经元 改变被动和主动机械负荷对骨发育的影响和间接影响， 这在以前是不可能的。最终，这项工作有可能改变目前的研究， 治疗模式从孤立的肌肉治疗目标到肌肉和骨骼的综合治疗 基于畸形和功能丧失的驱动因素的方法。我们预计我们的研究结果将提供新的 改善BPBI和其他神经肌肉损伤治疗的候选人。

PROJECT SUMMARY Brachial plexus birth injury (BPBI) is a traumatic perinatal neuromuscular injury causing muscle paralysis and lifelong arm impairment. Muscle paralysis in these children also leads to bone and joint consequences, including deformed growth of the scapula and humerus. BPBI occurs during a critical period of rapid musculoskeletal growth, but the parallel postnatal interactions of muscle and bone that drive these persistent deformities are not understood. Clinical reports and preliminary work suggest that short, contracted muscles after injury can alter mechanical loading of the shoulder consistent with observed bone deformity at macro- and microstructural levels. Altered active limb function with reduced range of motion and load bearing is also present; disuse is known to alter tissue growth and maturation. Finally, nerve injury in other conditions also affects bone growth directly, and direct effects in the postnatal period are not clear. Identifying appropriate targets for future treatment requires understanding which factors associated with altered bone and muscle development are most critical for driving altered growth. Almost nothing is known about the timing and progression of changes in underlying bone and muscle structure or metabolism following nerve injury occurring at birth to provide a foundation for clinical decision-making. Our primary hypothesis is that the bone deformity following BPBI is driven primarily by the mechanical environment, derived from impaired longitudinal growth of paralyzed muscle and altered active functional loading beginning shortly after injury. We will apply our unique rodent and computational models of BPBI that probe the separate contributions of nerve injury and muscle contracture to perform complementary assessments of the relative contributions of nerve injury, passive muscle loading, and active functional loading following BPBI to bone deformity. We will do so using 1) previously validated rat neurectomy models of brachial plexus injury and our unique disarticulation model of altered loading and 2) an integrated computational model to determine which specific features of bone deformity following BPBI are driven primarily by each potential driver. This R01 project, conducted by a multidisciplinary team with expertise in orthopedic surgery and biomechanical engineering, has high potential to elucidate the role of denervation in the parallel development of bone and muscle that occurs postnatally. Our innovative study design permits us to isolate both direct neural effects and indirect effects from altered passive and active mechanical loading on bone development in a way that has not previously been possible. Ultimately, this work has the potential to shift current research and treatment paradigms from an isolated focus on muscle as a treatment target to an integrated muscle and bone approach based on driving factors of deformity and loss of function. We anticipate our results will provide new candidates for improved treatment of BPBI and other neuromuscular injuries.