Basic and Clinical Study on Artificial Vertebral Body and Artificial Intervertebral Disc.

1.人工椎体(AVB)我们制作了一个新的AVB。通过力学试验、耐力试验和动物实验，证实了其安全性和实用性。应用该AVB进行了腰椎转移性肿瘤的椎体置换手术。它们是内杆、外杆、环、垫圈和螺丝。AVB的高度可以在应用于脊柱后通过旋转环来轻松改变。特殊设计的AVB钢板部分使用骨水泥固定在椎骨的骨沟中。将特制的犬AVB应用于犬的第4腰椎，用显微X线片评价其稳定性。术后4周，在骨水泥和终板周围可见新生骨组织。此外，还观察到40微米厚的纤维组织层。人颈椎的AVB也用于猴的第4腰椎。术后6个月AVB固定稳定。在耐力试验中，AVB经100000次垂直压缩(3000N)和100000次扭转(20 Nm)后均未断裂。2.用松质骨钉将其固定在椎体上，制成新型人工椎间融合器。对不同类型的螺丝进行了拔出试验，螺距为1.8 mm、螺距为1.5 mm的螺丝具有最大的拔出力。我们还用钛网制作了多孔材料。兔股骨中可见骨向内生长，而狗的腰间盘中未见骨内长入，为进一步证实该制剂的安全性和实用性，还需进一步的大动物实验。

1. Artificial vertebral body (AVB)We made a new AVB. The safety and practicality were confirmed by mechanical test,endurance test, and animal experiment. An operation of vertebral body replacement using this AVB was performed on metastatic spinal tumor of lumbar spine.The new AVB is composed of five parts. They are inner rod, outer rod,ring,washer, and screw. The height of the AVB can be easily changed by revolving the ring after application to the spinal column. The specially designed plate-portion of the AVB is fixed into the bony groove of the vertebra using bone cement. The mechanical stability of the fixation is better than those of conventional methods.Specially made AVB for dogs were applied to canine 4th lumbar vertebrae to evaluate the stability using microradiograph. Newly formed bone tissue was found around the bone cement and endplates at 4 weeks after surgery. A thin fibrous tissue layer of 40micrometer in thickness was also obserbed. AVB's for human cervical spine were also used for 4th lumbar vertebra of monkey. AVB fixation was stable after 6months from operation. No metal powder nor ion release was found aroud AVB.In the endurance test, the AVB was not broken after 100000 vertical compression test with 3000N and after 100000 torsional tests with 20Nm.2.Artificial intervertebral disc (AID)We made new AID using cancellous screws for fixation of itself to vertebral body. Pull out tests on various types of screw were done and the screw with 1.8mm in pitch and 1.5mm in thread height showed maximum pull out force. We also made porous material using titanium mesh. Bone ingrowth occured into the mesh in rabbit femur but it didn't occured in dog's intervertebral discs.To confirm the safety and practicality of this AID, further experiment using bigger animal is necessary.