Department of Orthopedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.
Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
Bone. 2018 Jul;112:90-96. doi: 10.1016/j.bone.2018.04.005. Epub 2018 Apr 9.
Diffuse idiopathic skeletal hyperostosis (DISH) is an increasingly prevalent ankylosing condition. Patients with DISH have an increased risk of spinal fractures, hypothetically the result of biomechanical changes in the spine. The aim of this study was to analyze the occurrence of biomechanical stress shielding in patients with DISH. To do this, bone mineral density (BMD) was measured longitudinally in the vertebral bodies of subjects with and without DISH and in the newly formed bone of subjects with DISH. The presence of DISH was evaluated using Resnick criteria on two chest computed tomography (CT) scans taken at least 2.5 years apart from subjects over 50 years of age. Three groups were identified: pre-DISH (individuals who developed DISH after the first CT scan), definite DISH (individuals who had DISH on both CT scans), and controls (individuals with no DISH). Hounsfield units (HU) were measured in the newly formed bone and in predefined anterior and posterior portions of the involved vertebral bodies. Mean BMD of the newly formed bone increased significantly (mean ΔHU 137.5; p < 0.01) during a mean interval of 5 years in the cranial, middle, and caudally involved vertebral segments of both DISH groups. Mean BMD of the vertebral bodies in the ankylotic segments in the DISH groups did not significantly differ from that of the non-ankylotic vertebral bodies of the same subject. In contrast to our hypothesis, the HU value of the vertebral body decreased more in the control group than in the DISH groups; however, statistical significance was only reached at the cranial level in the anterior part of the vertebral body (p = 0.048). Our data suggest that 1) vertebral BMD is not influenced by the presence of DISH and 2) increased spinal stiffness may play a more important role than vertebral BMD in the increased fracture risk of and the typical fracture patterns observed in individuals with DISH.
弥漫特发性骨肥厚（DISH）是一种日益普遍的强直性疾病。患有 DISH 的患者脊柱骨折的风险增加，这可能是脊柱生物力学变化的结果。本研究旨在分析 DISH 患者中生物力学应力屏蔽的发生情况。为此，对有和无 DISH 的受试者的椎体以及有 DISH 的受试者新形成的骨进行了纵向骨矿物质密度（BMD）测量。在年龄超过 50 岁的受试者中，使用 Resnick 标准在两次胸部 CT（CT）扫描上评估 DISH 的存在，两次 CT 扫描之间至少相隔 2.5 年。确定了三个组：DISH 前期（首次 CT 扫描后出现 DISH 的个体）、明确 DISH（两次 CT 扫描均有 DISH 的个体）和对照组（无 DISH 的个体）。在新形成的骨中和受累椎体的预定前、后部分测量了 Hounsfield 单位（HU）。在 DISH 两组的颅、中、尾受累椎体的节段中，新形成的骨的平均 BMD 在平均 5 年的时间内显著增加（平均ΔHU 137.5；p<0.01）。DISH 两组的强直性节段的椎体 BMD 与同一受试者的非强直性椎体的 BMD 无显著差异。与我们的假设相反，HU 值在对照组中比 DISH 组下降更多；然而，在前部椎体的颅部水平仅达到统计学意义（p=0.048）。我们的数据表明：1）椎体 BMD 不受 DISH 存在的影响；2）脊柱僵硬度的增加可能比椎体 BMD 更重要，在 DISH 患者中增加的骨折风险和典型的骨折模式中发挥作用。
