Gay Max Hans-Peter, Born Gordian, Mehrkens Arne, Wittig Holger, Müller-Gerbl Magdalena
Institute of Anatomy, Department of Biomedicine, Musculoskeletal Research, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland.
Department of Biomedicine, Tissue Engineering, University of Basel, Hebelstrasse 20, 4056 Basel, Switzerland.
N Am Spine Soc J. 2022 Feb 12;9:100102. doi: 10.1016/j.xnsj.2022.100102. eCollection 2022 Mar.
Lower back pain is a common condition with significant morbidity and economic impact. The pathophysiology is poorly understood but is in part attributable to degenerative disc disease (DDD). The healthy intervertebral disc ensures spine functionality by transferring the perceived load to the caudally adjacent vertebrae. The exposure to recurring mechanical load is mirrored in the mineralization pattern of the subchondral bone plate (SBP), where increased bone density is a sign of repetitive localized high stress. Computed tomography -osteoabsorptiometry (CT-OAM) is a technique based on conventional CT scans that displays the mineral density distribution in the SBP as a surface-color map. The objective of this study was to measure and analyze the SBP mineral density patterns of healthy lumbar intervertebral disc (IVDs) and those suffering DDD using CT-OAM densitograms. These findings should provide in vitro insight into the long-term morphological properties of the IVD and how these differ in the state of disc degeneration.
The CT-data sets of spines from 17 healthy individuals and 18 patients displaying DDD in the lumbar spine were acquired. Individual vertebrae of both cohorts were 3D reconstructed, processed using image analysis software, and compared to one another. Maximum intensity projection of the subchondral mineralization provided surface densitograms of the SBP. The relative calcium concentration, the local maxima of mineralization, and a mean surface projection of level-defined SBPs were calculated from the densitogram and statistically compared.
The inferior SBP, adjacent to degenerating disc, display an 18-41 % higher relative calcium concentration than their healthy counterparts. In the opposing superior SBPs the relative calcium content is significantly increased. Whereas it is reasonably consistent for L1-L3 (L1: 132 %, L2: 127 %, L3: 120 %), the increase grows in caudal direction (L4: 131 %, L5: 148 %, S1: 152 %). Furthermore, a change in the areal distribution of excessive mineralization can be differentiated between healthy and diseased motion segments.
The acquired data provide in vitro proof of the mechanical and anatomical properties of the SBP in relation to the state of disc degeneration. In conjunction with the diagnostic use of CT-osteoabsorptiometry, our data provide a basis for a non-invasive and sensitive technique that correlates with disc functionality. This could be promising in various cases, from early identification of early stages of DDD, tracking disease progression, and assessing the repercussions of surgical procedures or experimental therapies.
下背痛是一种常见病症，具有较高的发病率和经济影响。其病理生理学机制尚不清楚，但部分归因于椎间盘退变（DDD）。健康的椎间盘通过将感知到的负荷传递至相邻的尾侧椎体来确保脊柱的功能。反复机械负荷的作用反映在软骨下骨板（SBP）的矿化模式中，骨密度增加是重复性局部高应力的标志。计算机断层扫描 - 骨吸收测量法（CT - OAM）是一种基于传统CT扫描的技术，它将SBP中的矿物质密度分布显示为表面颜色图。本研究的目的是使用CT - OAM密度图测量和分析健康腰椎间盘（IVD）和患有DDD的腰椎间盘的SBP矿物质密度模式。这些发现应能为IVD的长期形态学特性及其在椎间盘退变状态下的差异提供体外见解。
获取了17名健康个体和18名患有腰椎DDD患者的脊柱CT数据集。对两组的单个椎体进行三维重建，使用图像分析软件进行处理，并相互比较。软骨下矿化的最大强度投影提供了SBP的表面密度图。从密度图计算相对钙浓度、矿化的局部最大值以及定义水平的SBP的平均表面投影，并进行统计学比较。
与退变椎间盘相邻的下SBP的相对钙浓度比其健康对应物高18% - 41%。在相对的上SBP中，相对钙含量显著增加。虽然L1 - L3相对较为一致（L1：132%，L2：127%，L3：120%），但这种增加在尾侧方向逐渐增大（L4：131%，L5：148%，S1：152%）。此外，健康和患病运动节段之间过度矿化的面积分布变化可以区分。
所获取的数据为SBP与椎间盘退变状态相关的力学和解剖学特性提供了体外证据。结合CT - 骨吸收测量法的诊断应用，我们的数据为一种与椎间盘功能相关的非侵入性和敏感技术提供了基础。这在各种情况下可能都很有前景，包括早期识别DDD的早期阶段、跟踪疾病进展以及评估手术程序或实验性治疗的影响。
