Micro-CT evaluation and histological analysis of screw-bone interface of expansive pedicle screw in osteoporotic sheep.
- Author:
Shi-yong WAN
1
;
Wei LEI
;
Zi-xiang WU
;
Rong LV
;
Jun WANG
;
Suo-chao FU
;
Bo LI
;
Ce ZHAN
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Bone Screws; Bone and Bones; diagnostic imaging; pathology; Female; Osteoporosis; diagnostic imaging; pathology; Sheep; Tomography, X-Ray Computed
- From: Chinese Journal of Traumatology 2008;11(2):72-77
- CountryChina
- Language:English
-
Abstract:
OBJECTIVETo investigate the properties of screw-bone interface of expansive pedicle screw (EPS) in osteoporotic sheep by micro-CT and histological observation.
METHODSSix female sheep with bilateral ovariectomy-induced osteoporosis were employed in this experiment. After EPS insertion in each femoral condyle, the sheep were randomly divided into two groups: 3 sheep were bred for 3 months (Group A), while the other 3 were bred for 6 months (Group B). After the animals being killed, the femoral condyles with EPS were obtained, which were three-dimensionally-imaged and reconstructed by micro-CT. Histological evaluation was made thereafter.
RESULTSThe trabecular microstructure was denser at the screw-bone interface than in the distant parts in expansive section, especially within the spiral marking. In the non-expansive section, however, there was no significant difference between the interface and the distant parts. The regions of interest (ROI) adjacent to EPS were reconstructed and analyzed by micro-CT with the same thresholds. The three-dimensional (3-D) parameters, including tissue mineral density (TMD), bone volume fraction (BVF, BV/TV), bone surface/bone volume (BS/BV) ratio, trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp), were significantly better in expansive sections than non-expansive sections (P less than 0.05). Histologically, newly-formed bony trabeculae crawled along the expansive fissures and into the center of EPS. The newly-formed bones, as well as the bones at the bone-screw interface, closely contacted with the EPS and constructed four compartments.
CONCLUSIONSThe findings of the current study, based on micro-CT and histological evaluation, suggest that EPS can significantly provide stabilization in osteoporotic cancellous bones.