Using Musculoskeletal Models to Assess FES Rowing for Skeletal Health After SCI

描述(由申请人提供)： 退伍军人健康管理局被认为是美国最大的为脊髓损伤(SCI)患者提供医疗保健的机构。仅在2004年，与治疗退伍军人管理局脊髓损伤患者相关的直接医疗费用就超过了7亿美元。据估计，一个25岁的高位四肢瘫痪患者一生的医疗费用为450万美元。 而且每年都在增加。导致这一高成本的一种常见疾病是与废弃相关的骨质疏松症和需要长期住院的病理性骨折。在脊髓损伤患者的下肢保持骨骼健康被普遍认为是一个非常可取的临床目标，然而，事实证明，这个目标很难实现。到目前为止，无论是药物治疗还是非药物治疗在临床试验中都没有产生特别令人鼓舞的结果。最近对脊髓损伤后骨丢失的非药物治疗的综合综述发现，使用功能性电刺激(FES)的高强度运动 下肢可以对骨骼产生有益的影响。这篇综述的一个关键结论是，训练的持续时间和骨骼内机械刺激的强度似乎是减少骨丢失的关键因素。在迄今为止文献中出现的唯一一项关于FES赛艇对骨密度影响的研究中，英国的研究人员在2011年报告了一名脊髓损伤后12年的患者股骨颈骨密度增加的情况，他是一名狂热的FES赛艇运动员。最近，这些研究人员分享了初步结果，表明同一人胫骨近端的小梁骨具有显着的骨保护作用。然而，目前尚不清楚是否可以在参与临床可行的划船干预的其他个人中广泛实现对骨骼健康的同样好处。 程序。此外，已报道的其他非药物干预的不同结果表明，在设计特定的干预方案时，必须考虑患者在肌肉调节和电刺激时的疲劳方面的差异，即每周锻炼的次数、划船强度、 有耐心的话。由于缺乏关于FES赛艇对骨密度影响的数据，我们建议进行一项专门关注骨骼健康的FES赛艇研究。这一研究领域的长期目标是减少脊髓损伤患者因废用骨质疏松导致的下肢骨折的发生率。这项长期努力的试点阶段的目标是确定FES赛艇是否可以预防或显著减轻急性和亚急性脊髓损伤患者的下肢骨丢失。在这个试点阶段，我们将解决两个问题：1)以前在一名SCI患者中发现的FES-赛艇的积极益处能否在临床上合理干预时间的更大一组患者中重复；2)赛艇干预后个体间成骨反应的差异能否用赛艇干预后骨骼力史的差异来解释？我们的初步研究有四个具体目标：1)获得最先进的FES辅助赛艇系统；2)收集进行FES辅助赛艇的脊髓损伤飞行员组的运动学和运动学数据；3)使用肌肉骨骼模拟工具估计赛艇过程中特定受试者的骨骼力量；以及4)根据受试者特定的肌肉骨骼模型和特定受试者的FES赛艇历史，使用骨适应理论评估FES赛艇对中度骨质损失的潜力。在这项初步研究的结论中，我们希望有证据表明，能够产生足够的骨骼负荷史的FES-赛艇训练方案可以在减少脊髓损伤后的骨丢失方面有显着的效果。如果成功，这将是一个关键的证明，即FES赛艇具有其他运动方式无法比拟的骨骼益处。同样重要的是，我们预计我们的结果将对理解负荷历史做出基本贡献，而负荷历史是改变脊髓损伤后骨丢失的自然历史所必需的。

DESCRIPTION (provided by applicant): The Veterans Health Administration is believed to be the largest single provider of health care to individuals with spinal cord injury (SCI) in the United States. In 2004 alone, the direct medical costs associated with the care of VA patients with SCI exceeded $700 million. The estimated lifetime healthcare cost for a single 25- year-old individual with high tetraplegia is $4.5 million and increasing yearly. A common condition that contributes to that high cost is disuse-related osteoporosis and pathologic fracture requiring prolonged hospitalization. Maintaining skeletal health in the lower limbs of individuals with SCI is universally recognized as a highly desirable clinical goal, however, that goal has proven difficult to achieve. Neither pharmacologic nor non-pharmacologic treatments have produced particularly encouraging results in clinical trials to date. A recent comprehensive review of non-pharmacological treatments for modulating bone loss after SCI found that high-intensity exercises using functional electrical stimulation (FES) of the lower limbs can have a beneficial effect on bone. A key conclusion from that review is that the duration of training and the intensity of the mechanical stimulus within the bone appear to be key factors in reducing bone loss. In the only study on the effect of bone density from FES-rowing that has appeared in the literature to date, researchers in England in 2011 reported increased bone density at the femoral neck in one individual who is 12-years post SCI and who is an avid FES-rower. Recently those same researchers shared preliminary results that demonstrate remarkable bone preservation in the trabecular bone at the proximal tibia of the same individual. However, it remains unknown if the same benefits to skeletal health can be widely achieved in other individuals participating in a clinically practicable, rowing intervention program. Furthermore, the dissimilar outcomes that have been reported for other non-pharmacological interventions suggest that differences among patients in muscle conditioning and fatigue during electrical stimulation must be taken into consideration when designing a specific intervention protocol, i.e., number of exercise sessions per week, rowing intensity, for a given patient. Given the paucity of data on the effect of FES-rowing on bone density, we are proposing an FES-rowing study that specifically focuses on bone health. The long-term goal of this area of research is to reduce the incidence of fracture from disuse-osteoporosis in the lower limbs of individuals with spinal cord injuries. The objective of the pilot phase of this long-term endeavor is to determine if FES-rowing can prevent or significantly attenuate bone loss in the lower limbs in individuals with acute and sub-acute SCI. In this pilot phase we will address two questions: 1) can the positive benefits from FES-rowing previously found in one individual with SCI be repeated in a larger group of individuals with a clinically reasonable intervention duration; and 2) can the inter-individual differences in osteogenic response following a rowing intervention be explained by the differences in skeletal force histories from the rowing intervention? Our pilot study has four specific aims: 1) to acquire a state-of-the-art FES-assisted rowing system; 2) to collect kinematic and kinetic data for a pilot group of individuals with spinal cord injury performing FES-assisted rowing; 3) to use musculoskeletal simulation tools to estimate subject-specific skeletal forces during rowing; and 4) to use bone adaptation theory to evaluate the potential of FES-rowing to moderate bone loss based on the subject-specific musculoskeletal models and subject-specific FES-rowing histories. At the conclusion of this pilot study we expect to have evidence to show that an FES-rowing exercise regimen that generates a sufficient skeletal loading history can have a significant effect on reducing bone loss following SCI. If successful, this will represent a key demonstration that FES-rowing has a skeletal benefit not yet matched by other exercise modalities. Equally as important, we expect our results will make a fundamental contribution to the understanding of the loading history that is required to alter that natural history of bone loss following SCI.