In-vivo Lumbar Disc Deformation

描述（由申请人提供）：腰椎退行性椎间盘疾病（DDD）伴有椎间盘结构性失效。百分之七十五（75%）的成年人在其一生中的某个时候会经历继发于腰椎DDD的下背痛（LBP）。1，2融合受累运动节段是目前最常见的严重DDD手术治疗。3 -5然而，放射学随访研究（早在手术后一年）显示，多达80%的的患者可能在相邻椎体节段发生进行性退变，而不管融合方法如何。6 -9通常认为，椎体运动学和椎间盘内压力的改变是导致退变发展的重要生物力学因素10，11。因此，定量了解融合手术前后正常人脊柱和病理脊柱的体内椎体运动和椎间盘变形有助于揭示DDD发展过程中的生物力学因素。然而，文献综述显示，没有关于活体人类受试者椎间盘变形的数据报告。最近，我们已经开发了一种组合的双透视图像系统（DFIS）和MRI为基础的建模技术，以测量在体内人体椎间盘变形承重条件下。在这项探索性R21提案中，总体目标是使用DFIS和MRI技术联合确定动态人体活动期间的椎体运动和椎间盘变形。首先，我们将比较正常受试者和重度DDD患者在融合手术前进行动态对称和不对称举重活动时腰椎（L1-2、L2-3、L3-4和L4-5）的椎间盘变形（压缩和剪切）。其次，我们将精确地量化并比较DDD患者手术融合后腰椎间盘的压缩和剪切变形与手术前和正常受试者在相同活动期间测量的压缩和剪切变形。该研究将首次尝试定量测定正常受试者和重度DDD患者在功能动态载荷条件下的体内椎体运动和腰椎间盘变形。这些数据将量化DDD和DDD节段的手术融合对椎体运动和椎间盘沿着动态腰椎运动路径的变形的影响，因此，本研究将为改善目前治疗DDD患者的手术方式提供指导，以防止术后相邻节段的退变。这些数据对于建立设计未来椎间盘置换植入物、动态稳定系统、脊柱生物制品或可适应生理椎间盘变形的组织工程产品的目标函数也是非常宝贵的。 公共卫生相关性：本研究将探讨人体腰椎间盘在动态举重运动中的压缩与剪切变形。它还将确定手术融合病变L5-S1椎间盘对相邻椎体水平腰椎间盘变形的影响。所获得的知识不仅将提供对疾病过程的洞察，而且还将有助于改善治疗策略。

DESCRIPTION (provided by applicant): Degenerative Disc Disease (DDD) of the lumbar spine is accompanied with structural failure of the disc. Seventy-five percent (75%) of all adults will experience lower back pain (LBP) secondary to DDD in the lumbar spine at some point in their lifetime.1,2 Fusion of the involved motion segments is currently of the most common surgical treatment of severe DDD.3-5 However, radiographic follow-up studies (from as early as one year following surgery) have revealed that as many as 80% of patients may develop progressive degeneration in the adjacent vertebral segments regardless of the method of fusion.6-9 Altered vertebral kinematics and intra-disc pressure have been generally assumed to be important biomechanical factors leading to the degenerative development 10,11. Therefore, a quantitative knowledge of the in-vivo vertebral motion and disc deformation in normal human spines and in pathological spines before and after fusion surgery is instrumental to reveal the biomechanical factors accompanied with DDD development process. However, a literature review revealed that there is no data reported on the intervertebral disc deformation in living human subjects. Recently, we have developed a combined dual fluoroscopic image system (DFIS) and MRI based modeling technique to measure in-vivo human intervertebral disc deformation under weightbearing conditions. In this exploratory R21 proposal, the overall goal is to determine the vertebral motion and intervertebral disc deformation during dynamic human body activities using the combined DFIS and MRI technique. Firstly, we will compare intervertebral disc deformation (compressive and shear) of the lumbar spines (L1-2, L2-3, L3-4 and L4-5) of normal subjects and patients with severe DDD before fusion surgery during dynamic symmetric and asymmetric weight-lifting activities. Secondly, we will accurately quantify and compare the compressive and shear deformation of the lumbar intervertebral discs of the DDD patients after surgical fusion with those measured before surgery and those of normal subjects during the same activities. The proposed research will be the first attempt to quantitatively determine in-vivo vertebral motion and lumbar intervertebral disc deformation in normal subjects and patients with severe DDD under functional dynamic loading conditions. The data will quantify the effect of DDD and surgical fusion of the DDD segment on the vertebral motion and deformation of the intervertebral disc along the dynamic lumbar spine motion path. Therefore, this research will provide guidelines for the improvement of current surgical modalities for the treatment of DDD patients so that post-operative degeneration of adjacent segments can be prevented. The data can also be invaluable for establishing objective functions for designing future disc replacement implants, dynamic stabilization systems, spine biologics or tissue engineered products that can accommodate physiological intervertebral disc deformation. PUBLIC HEALTH RELEVANCE: This proposed project will investigate the compressive and shear deformation of human lumbar intervertebral discs during dynamic weight-lifting activities. It will also determine the effect of surgical fusion of diseased L5-S1 disc on lumbar disc deformation at the adjacent vertebral levels. The obtained knowledge will not only provide insight into the disease process but will also be useful for improvement of treatment strategies.