Assessing Bone Health after SCI: Establishing Evidence for a Clinical Protocol

退伍军人健康管理局(VHA)是为有以下疾病的个人提供医疗保健的最大单一机构 美国的脊髓损伤(SCI)。2016年，瘫痪的美国退伍军人估计有4.3万人 患有脊髓损伤的退伍军人得到了VHA的照顾。这种护理每年的成本是相当高的。2015年，总成本 在脊髓损伤后的第一年，从52万美元到110万美元不等；经常性成本从6.9万美元到1.85万美元不等 每名患者每年。随着脊髓损伤后预期寿命的增加，终生成本也在继续增加。一把钥匙 脊髓损伤后高医疗费用的贡献者是脆性骨折，通常需要长时间住院和 专科护理。多达四分之三的脊髓损伤患者将在其一生中遭受脆性骨折。 骨折会导致严重的医疗并发症，丧失独立性，丧失生产力，所有这些都会导致 在大量的直接和间接成本中。SCI临床医生和患者一致认为，保持积极的生活方式是 不仅对一般健康至关重要，而且对肌肉骨骼健康也至关重要。考虑到大量的骨质流失， 发生在脊髓损伤后的下肢，然而，临床医生必须始终认识到 骨折，尤其是那些有较多慢性损伤的人。 通过双能X射线吸收法(DXA)扫描测量骨密度(BMD) 评估健全个体骨质疏松症的临床金标准。准确的诊断很重要 因为它指导治疗，并帮助告知患者和医生哪些活动可以进行，哪些不可以进行 安全无恙。与健全个体的情况不同，没有临床标准也没有共识 评估脊髓损伤患者的下肢骨骼健康状况。对于健全的个人，标准是 扫描的部位是脊柱和髋部，这是与年龄相关的人常见的骨折部位 骨质疏松。然而，对于那些患有脊髓损伤的人来说，大多数骨折发生在膝盖上方和下方。臀部和臀部 脊柱骨密度不是腿部远端骨折的良好预测指标，目前还没有标准化的标准。 目前已有评估膝关节附近骨骼健康的方案。脊髓损伤临床医生继续面临关键的 问题是：我的病人参加某些康复活动、康乐和运动是否安全？ 活动，还是使用外骨骼进行行走？目前，还没有基于证据的答案。 问题。该项目的目的是验证骨密度评估的扫描方案，该方案将 使临床医生能够解决这个问题。这反过来将允许临床医生开出处方并监测康复 适合特定患者骨骼健康的治疗和娱乐活动。 在过去的三十年里，已经提出了十几种不同的协议来扫描 自2005年开始实施的9个方案，包括在脊髓损伤患者的膝关节上方和以下的区域。那些 没有对协议的敏感性或精确度进行全面评估或比较，也没有 为健全的个人确定了规范性的参考值。我们的研究有四个具体目标。 目标1是为已提出的用于骨的多种DXA协议生成标准数据库 股骨远端和胫骨近端的密度扫描。目标2是确定和排序这些参数的精度 在身体健全的人身上的协议。目标3是检查膝关节DXA方案的确定精度 在目标1中，但在损伤后4年患有脊髓损伤的个体，并观察高分辨率QCT和外周- 与DXA相比，QCT扫描提供了有临床价值的补充数据。目标4是测量骨骼 伤后1至4年患者随时间的变化，对于DXA，将这些变化与最小 根据每个候选膝部DXA协议的精度确定的可检测变化。这样做的结果 这项研究将立即具有临床实用价值，并将为未来骨折风险的发展奠定基础 专门针对脊髓损伤患者的评估工具，可与现有的风险评估工具相媲美，能够- 身体健全的个体。下一步将立即在临床上实施经过验证的DXA协议。

The Veterans Health Administration (VHA) is the largest single provider of heath care to individuals with spinal cord injury (SCI) in the United States. For 2016, Paralyzed Veterans of America estimates that 43,000 veterans with SCI received care from VHA. The annual cost of that care is substantial. In 2015, the total costs during the first year following an SCI ranged from $520K to $1.1M; recurring costs ranged from $69K to $185K per patient per year. Lifetime costs also continue to increase as life expectancy post-SCI increases. A key contributor to the high medical cost post-SCI is fragility fracture, often requiring prolonged hospitalization and specialized care. Up to three-quarters of individuals with SCI will sustain a fragility fracture in their lifetime. Fractures lead to serious medical complications, a loss of independence, and a loss of productivity, all resulting in substantial direct and indirect costs. SCI clinicians and patients agree that maintaining an active lifestyle is critical not only for general health, but also for musculoskeletal health. Given the substantial loss of bone that occurs in the lower limbs following SCI, however, clinicians must always be cognizant of the possibility of fracture, especially for those with more chronic injuries. Bone mineral density (BMD) measurement from a Dual-energy X-ray Absorptiometry (DXA) scan is the clinical gold standard for osteoporosis assessment in able-bodied individuals. Accurate diagnosis is important since it guides treatment and it helps to inform patients and doctors what activities can and can't be performed safely. Unlike the case with able-bodied individuals, there is no clinical standard and no consensus for assessing skeletal health in the lower limbs of individuals with SCI. For able-bodied individuals, the standard sites for scanning are the spine and hip, which are common sites of fracture in those with age-related osteoporosis. For those with SCI, however, most fractures occur just above and just below the knee. Hip and spine BMD are not good predictors of fracture at distal sites in the legs and, at present, no standardized protocols exist for assessing skeletal health near the knee. SCI clinicians continue to be faced with a critical question which is: Is it safe for my patient to participate in certain rehabilitation activities, recreation and sports activities, or to use an exoskeleton for ambulation? Currently, there is no evidence-based answer to that question. The purpose of this project is to validate scan protocols for bone mineral density assessment that will enable clinicians to address that issue. This in turn will allow clinicians to prescribe and monitor rehabilitation therapies and recreational activities that are appropriate for a particular patient given his or her skeletal heath. Over the past three decades more than a dozen different protocols have been proposed for scanning the area above and below the knee in patients with SCI, including nine protocols introduced since 2005. Those protocols have not been comprehensively assessed or compared for sensitivity or precision, nor have normative, reference values been determined for able-bodied individuals. Our study has four Specific Aims. Aim 1 is to generate normative databases for the multiple DXA protocols that have been proposed for bone density scanning of the distal femur and proximal tibia. Aim 2 is to determine and rank the precision of those protocols in able-bodied individuals. Aim 3 is to the determine precision for the knee DXA protocols examined in Aim 1, but in individuals with SCI >4 years post-injury, and to see if High-Resolution QCT and peripheral- QCT scanning provide clinically valuable complementary data compared to DXA. Aim 4 is to measure bone changes over time in patients 1 to 4 years post-injury and, for DXA, to compare those changes to the least detectable change determined from the precision for each candidate knee DXA protocol. The results of this study will have immediate clinical utility and will lay the groundwork for future development of a fracture risk assessment tool specific for persons with SCI, comparable to risk assessment tools already available for able- bodied individuals. Clinical implementation of validated DXA protocols will be the immediate next step.