1988 Fiscal Year Final Research Report Summary
Basic and Clinical Study on Artificial Vertebral Body and Artificial Intervertebral Disc.
| Project/Area Number |
62480316
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Chiba University |
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Principal Investigator |
KITAHARA Hiroshi Associate Prof., School of Medicine, Chiba University, 医学部, 助教授 (30114268)
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| Co-Investigator(Kenkyū-buntansha) |
EMI Toshihiko Associate Director, High-technology Research Laboratories, Technical Research Di, 副所長 (30250822)
TAKAHASHI Kazuhisa Assistant, School of Medicine, Chiba University, 医学部, 助手 (20179477)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Artificial vetebral body / Artificial intervertebral disc / Spine / Metastasis / Vertebral body replacement / 人工椎間板 |
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| Research Abstract |
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.
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