The effect of an enhanced load sharing dynamic pedicle screw fixation device on the bone mineral density and bone structure of vertebrae
- VernacularTitle:增加载荷分享的动力内固定对椎体骨量和骨结构的影响
- Author:
Huazi XU
;
Hongpu SONG
;
Yonglong CHI
- Publication Type:Journal Article
- Keywords:
Spine;
Internal fixators;
Bone density;
Histology;
Stress, mechanical
- From:
Chinese Journal of Orthopaedics
1998;0(12):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare the influence of the dynamic device(DD) of pedicle screw fixation and its equivalent rigid device (RD) on bone mineral density and bone structure of the vertebrae. Methods 24 goats were randomly divided into 4 groups: control group, single posterolateral fusion group, dynamic device with posterolateral fusion group and rigid device with posterolateral fusion group. After 24 weeks postoperative observation, the animals were sacrificed and the fixed lumbar spines were harvested. The bone mineral density (BMD) of these harvested specimens was measured by quantitative computed tomography (QCT). Then the L3 segment was embedded in methyl methacrylate and sectioned after alcoholic dehydration. Undecalcified slides (50 ?m in thickness) were stained with toluidine blue. Quantitative histologic analysis was performed in a semiautomatic way. The static parameters consisted of trabecular bone volume (TBV), the mean trabecular plate thickness (MTPT) and mean trabecular spacing (Tb.Sp). The main dynamic histomorphometric parameter, bone mineralization rate (MAR), was calculated by measuring the mean distance between two flurochrome labelings. Results The BMD in the rigid device group decreased significantly compared with control group (P
