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脊髓损伤（SCI）患者最大的单一医疗保健提供者。仅在2004年，与脊髓损伤患者护理相关的直接医疗费用就超过7亿美元。一个25岁的高度四肢瘫痪患者的估计终身医疗费用为450万美元 并且逐年增加。造成这种高成本的一种常见情况是废用性骨质疏松症和病理性骨折，需要长期住院治疗。维持SCI患者下肢的骨骼健康被普遍认为是一个非常理想的临床目标，然而，该目标已被证明难以实现。迄今为止，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。 最近一项关于非药物治疗调节SCI后骨丢失的综合综述发现，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。该综述的一个关键结论是，训练的持续时间和骨内机械刺激的强度似乎是减少骨丢失的关键因素。在迄今为止出现在文献中的唯一一项关于FES划船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SCI后12年并且是狂热的FES划船者的股骨颈骨密度增加。最近，这些研究人员分享了初步的结果，表明在同一个体的胫骨近端骨小梁中有显着的骨保存。然而，它仍然是未知的，如果同样的好处，骨骼健康可以广泛地实现在其他个人参与临床上可行的，划船干预 程序.此外，已报告的其他非药物干预的不同结果表明，在设计特定干预方案时，必须考虑患者在电刺激期间肌肉调节和疲劳方面的差异，即，每周运动次数，划船强度， 给病人。 由于缺乏关于FES划船对骨密度影响的数据，我们提出了一项专门关注骨骼健康的FES划船研究。这一研究领域的长期目标是减少脊髓损伤患者下肢废用性骨质疏松症骨折的发生率。这项长期奋进的试点阶段的目标是确定FES划船是否可以预防或显著减轻急性和亚急性SCI患者下肢的骨丢失。在这个试点阶段，我们将解决两个问题：1）是否可以从FES划船以前发现在一个人与SCI的积极效益，重复在一个更大的群体的个人与临床合理的干预时间;和2）是否可以在划船干预后的成骨反应的个体间差异，由划船干预的骨骼力量的历史的差异来解释？ 我们的试点研究有四个具体目标：1）获得一个国家的最先进的FES辅助划船系统; 2）收集运动学和动力学数据的试点组与脊髓损伤的个人进行FES辅助划船; 3）使用肌肉骨骼模拟工具，以估计特定的骨骼力量在划船过程中;（4）根据受试者特定的肌肉骨骼模型和受试者特定的FES划船史，使用骨适应理论来评估FES划船减轻骨丢失的潜力。在这项初步研究的结论，我们希望有证据表明，一个FES划船运动方案，产生足够的骨骼负荷的历史可以有显着的效果，减少骨丢失后SCI。如果成功，这将是一个关键的证明，FES划船有骨骼的好处还没有匹配的其他运动方式。同样重要的是，我们希望我们的研究结果将为理解改变SCI后骨丢失的自然历史所需的负荷历史做出根本性的贡献。

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.