Dura mater against invasive ossification by grafted periosteum

硬脑膜在保护脊髓中起着重要作用。在脊柱韧带骨化的患者中，骨化有时会延伸到硬脑膜，这可能会导致严重的脊髓病。既往研究表明，脊柱韧带骨化累及硬脑膜，术后预后较差。为探讨骨膜是否也可引起硬脑膜骨化，将兔桡骨骨膜移植到硬脑膜内进行了实验研究。实验动物40只，体重1.5~2.0 kg，随机分为对照组和骨膜移植组。前者20只，仅行L5/6椎板切除，后者20只，去除桡骨骨膜，移植到L5/6硬脑膜上。结果显示，对照组L5/6手术部位硬脑膜背侧周围均有炎症反应和瘢痕组织形成，但未见退变和骨化。硬脑膜保持正常，无任何组织学改变。在骨膜移植组，20只动物L5/6硬脑膜背侧周围均可见骨膜移植诱导的新骨形成。由于移植的骨膜，硬脑膜在形成新骨的过程中受到侵袭性骨化的影响。在20只动物中，有11只(55%)的硬脑膜没有保持正常的组织结构，表现出轻微但形态多样的变化。这种变性包括硬脑膜胶原束的水肿、变薄、分离和萎缩。然而，没有一只动物(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.