Influences of BioFlex dynamic stabilization system fixation on the stress of adjacent segments of intervertebral disc at different decompression ranges
10.3969/j.issn.2095-4344.2016.35.005
- VernacularTitle:不同减压范围下行BioFlex动态稳定系统内固定对邻近节段椎间盘应力的影响
- Author:
Shengyu WAN
;
Bo YANG
;
Xu LIN
- Publication Type:Journal Article
- From:
Chinese Journal of Tissue Engineering Research
2016;20(35):5203-5209
- CountryChina
- Language:Chinese
-
Abstract:
BACKGROUND:BioFlex system as a new pedicle screw fixation of dynamic stabilization device has less been reported concerning its biomechanics.
OBJECTIVE:To study the effect of BioFlex system fixation at different decompression ranges on disc stress at adjacent segments.
METHODS:Eight samples of fresh calf spines were used. Under physiologic axial loads (500, 900, 2 300 N), electronic universal testing machine was used to simulate the lumbar spine at three physiological states (standing, sitting and bending, standing on a portable 20 kg weight and bending). Progressive decompression modeling for each specimen and dividing into five groups:(1) complete status group;(2) complete status+BioFlex group;(3) partial laminectomy+BioFlex group;(4) 1/2 medial facetectomy+BioFlex group;(5) total facetectomy+BioFlex group. Strain gauges were used to record the stress of disc annulus. Electronic universal testing machine was used to record load-displacement curve and calculate stiffness.
RESULTS AND CONCLUSION:(1) The stress of the adjacent segment of the intervertebral disc increased with the expansion of the range of decompression. Compared with the complete status, stress obviously increased after BioFlex fixation, showing significant differences (P<0.05). The stress was significantly increased in the 1/2 medial facetectomy+BioFlex group compared with the partial laminectomy+BioFlex group (P<0.05). However, no significant difference was detected between the partial laminectomy+BioFlex group and complete status+BioFlex group, and between total facetectomy+BioFlex group and 1/2 medial facetectomy+BioFlex group (P>0.05). (2) Axial stiffness reduced with the expansion of the range of decompression. Compared with the complete status, axial stiffness noticeably increased after BioFlex fixation. The difference was not significant among four kinds of reconstruction structures. (3) These findings confirmed that after BioFlex fixation, with the expansion of the range of decompression, the stress of adjacent segments of intervertebral disc gradual y increased, but different ranges of decompression cannot affect the stiffness of reconstruction structure.
