Dura mater against invasive ossification by grafted periosteum

硬脑膜在脊髓的保护中起着重要的作用。在脊柱韧带骨化的患者中，偶尔报告骨化延伸到硬脑膜，这可能导致严重的脊髓病。以往的研究表明，当脊柱韧带骨化累及硬脑膜时，术后预后较差。为探讨骨膜是否也能引起硬脑膜骨化，将兔桡骨骨膜移植到硬脑膜内。实验动物40只，体重1.5-2.0kg，随机分为对照组和骨膜移植组。前者包括20只接受L5/6椎板切除术的家兔，而后者包括20只从桡骨切除骨膜并移植到L5/6硬脑膜上的家兔。我们的结果是，在对照组中，所有动物在L5/6硬脑膜背面周围的手术部位均显示出炎症反应和瘢痕组织，但未显示出变性和骨化。硬脑膜保持正常，无任何组织学改变。在骨膜移植物组中，在所有20只动物的L5/6硬脑膜背侧部位周围，骨膜移植物诱导的新骨形成明显。硬脑膜在移植骨膜产生新骨的过程中受到侵袭性骨化的影响。20只动物中有11只（55%）的硬脑膜未保持正常的组织结构，表现为轻度但形态多样的改变。这些变性包括硬脑膜的胶原纤维束水肿、变薄、分离和萎缩。然而，没有动物（0%）显示硬脑膜骨化。

The dura mater plays an important role in the protection of the spinal cord. In patients with ossification in the spinal ligaments, the ossification is occasionally reported to extend to the dura mater, which may lead to serious myelopathy. Previous studies have shown that the postoperative prognosis is poor when ossification in the spinal ligaments involves the dura mater. To investi gate whether the periosteum could also cause ossification in the dura mater, a study was per formed in which the periosteum of the radius was transplanted to the dura mater in rabbits. Forty rabbits each weighing 1.5-2.0kg were used as the experimental animal, and were divided into a control group and a grafted periosteum group. The former consisted of 20 rabbits that underwent only laminectomy at L5/6, while the latter consisted of 20 rabbits in which the periosteum was removed from the radius, and was grafted onto the dura mater at L5/6. We resulted that, in the control group, all animals showed an inflammatory reaction and scar tissue at the operation site around the dorsal aspect of the dura mater at L5/6, but showed no degeneration and no ossification. The dura mater remained normal, without any histological change. In the periosteum graft group, new bone formation induced by the periosteum graft was apparent around the dorsal site of the dura mater at L5/6 in all 20 animals. The dura mater was affected by the invasive ossification in the process of producing new bone formation due to the grafted periosteum. The dura mater in eleven (55%) of the 20 animals did not keep normal organization, and showed mild but morpho logically diverse changes. Such degeneration included edema, thinning, separation and atrophy in the collagen bundles of the dura mater. However, none (0%) of the animals showed ossification in the dura mater.