Grant-in-Aid for General Scientific Research (A)
|Allocation Type||Single-year Grants |
|Research Institution||University of Tokyo |
KUROKAWA Takahide University of Tokyo, Orthopaedic Surgery, Professor, 医学部(病), 教授 (90010298)
MURASHIMA Ryutarou University of Tokyo, Orthopaedic Surgery, Assistant, 医学部(病), 助手 (90239517)
NAGANO Akira University of Tokyo, Orthopaedic Surgery, Associate Professor, 医学部(分), 助教授 (30111537)
落合 直之 東京大学, 医学部(病), 講師 (30134563)
小島 達自 東京大学, 医学部(病)・整形外科, 助手 (30161912)
|Project Period (FY)
1989 – 1992
Completed (Fiscal Year 1992)
|Budget Amount *help
¥34,900,000 (Direct Cost: ¥34,900,000)
Fiscal Year 1992: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1989: ¥28,400,000 (Direct Cost: ¥28,400,000)
|Keywords||External Fixator / Twisting Load / Remodeling / Bone Healing / Compression / Destruction / Sarcomere Length / Bone Mineral Density / 捻転変形 / 拘縮 / 高精度連続組織駆動装置 / 骨塩量 / 張力 / 仮骨延長 / 自動延長 / 組織形成 / 脚延長術 / 骨接合術 / 仮骨骨密度 / 組織張力 / 神経伝導速度 / 機械的骨誘導 / 骨形成 / 仮骨 / 骨密度測定 / 高精度駆動|
As a result of basic study, we found the following.
(1) Long bones in lower legs of adult rabbits can be torsionally deformed without osteotomy, by continuously twisting them with external fixators. As a result of twisting, periosteal and endosteal lamellar bones decreased, while osteonal bones increased. Osteonal remodeling was activated by such twisting.
(2) In lower legs of adult rabbits, both compression and distraction by Imm on the osteotomy site activate bone healing. Compression and distraction revealled the same effectiveness.
(3) We studied changes in sarcomere lengrh in situ, stretching the extensor digitorum longus (EDL) of mouses maximally and immobilizing them by a plaster cast. Sarcomere length shortened gradually for seven days. The length after seven days was the same as the that of EDL that has not been stretched. It is because sarcomeres recover their original length that skeletal muscles adapt to the new leg length in leg lengthening.
Result of our clinical study are as
(1) We succeeded in, producing an external fixator that realizes precise movements and made it suitable for practical use.
(2) The bone mineral density of callus in lengthened site was measured periodically with a dual energy X-ray absorptiometry (DXA). The bone mineral density of callus of femur was higher than that of tibia.
(3) As for relationship between leg lengthening speed and ankle contracture, ankle contracture is often observed when leg lengthening is conducted at a high speed. Contracture cannot be prevented by merely slowing the lengthening speed.
(4) As for relationship between leg lengthening speed and nerve conduction velocity, nerve conduction blocks are hardly observed when the lengthening speed is lower than 0.5mm/days. Conduction blocks are far less frequently observed when leg lengthening is conducted 1440 times a day for the lengthening speed of 0.5mm/day or more, compared with cases where lengthening is conducted only twice a day to achieve the same lengthening speed. Less