Pedicle Screw Hubbing in the Adult and Immature Thoracic Spine: A Biomechanical and Micro-Computed Tomography Evaluation

2013 ◽  
Vol 13 (9) ◽  
pp. S76
Author(s):  
Ronald A. Lehman ◽  
Daniel G. Kang ◽  
Adam Bevevino ◽  
Robert W. Tracey ◽  
John P. Cody ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pedicle Screw ◽  
Thoracic Spine ◽  
Micro Computed Tomography

scholarly journals Micro-computed tomography analysis of the lumbar pedicle wall

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253019
Author(s):  
Tomoyo Y. Irie ◽  
Tohru Irie ◽  
Alejandro A. Espinoza Orías ◽  
Kazuyuki Segami ◽  
Norimasa Iwasaki ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pedicle Screw ◽  
Area Fraction ◽  
Bone Area ◽  
Micro Computed Tomography ◽  
Medial Region ◽  
Lateral Region ◽  
Caudal Region ◽  
Pedicle Wall ◽  
Lumbar Pedicle

Background Although the pedicle is routinely used as a surgical fixation site, the pedicle wall bone area fraction (bone area per unit area) and its distribution at the isthmus of the pedicle remain unknown. The bone area fraction at the pedicle isthmus is an important factor contributing to the strength of pedicle screw constructs. This study investigates the lumbar pedicle wall microstructure based on micro-computed tomography. Methods Six fresh-frozen cadaveric lumbar spines were analyzed. Left and right pedicles of each vertebra from L1 to L5 were resected for micro-computed tomography scanning. Data was analyzed with custom-written software to determine regional variation in pedicle wall bone area fraction. The pedicular cross-section was divided into four regions: lateral, medial, cranial, and caudal. The mean bone area fraction values for each region were calculated for all lumbar spine levels. Results The lateral region showed lower bone area fraction than the medial region at all spinal levels. Bone area fraction in the medial region was the highest at all levels except for L4, and the median values were 99.8% (95.9–100%). There were significant differences between the lateral region and the caudal region at L1, L2 and L3, but none at L4 and L5. The bone area fraction in the lateral region was less than 64% at all spinal levels and that in the caudal region was less than 67% at the L4 and L5 levels. Conclusions This study provides initial detailed data on the lumbar pedicle wall microstructure based on micro-computed tomography. These findings may explain why there is a higher incidence of pedicle screw breach in the pedicle lateral and caudal walls.

scholarly journals Computerized three-dimensional pedicle morphometry from computed tomography images of the thoracic spine

2020 ◽  
Author(s):  
Dejan Knez ◽  
Tomaž Vrtovec
Keyword(s):  
Computed Tomography ◽  
Pedicle Screw ◽  
Thoracic Spine ◽  
Parametric Modeling ◽  
Chord Length ◽  
Screw Placement ◽  
Absolute Difference ◽  
Pedicle Screw Placement ◽  
Computed Tomography Images ◽  
Pedicle Width

Knowledge of pedicle morphometry is valuable for a safe and reliable pedicle screw placement. In this study, we performed and evaluated computerized pedicle morphometry measurements from preoperative computed tomography (CT) images of the thoracic spine from 26 subjects. Manual measurements of the pedicle width, height and chord length were obtained for 540 thoracic pedicles in selected cross sections of orthogonal and oblique multiplanar reconstructions (MPRs). Computerized measurements of the pedicle width, height, length, chord length, transverse angulation, sagittal angulation and cross-sectional area were obtained for the same pedicles by an automated method that is based on parametric modeling of vertebral structures in three dimensions (3D). Statistical analysis revealed that manual measurements from orthogonal MPRs were significantly different (p ≤ 0.0011) when compared to those from oblique MPRs and computerized measurement in 3D, with the respective mean absolute difference (MAD) ± standard deviation (SD) of 0.77 ± 0.56 mm and 0.74 ± 0.57 mm for the pedicle width, and 1.31 ± 1.08 mm and 1.45 ± 1.10 mm for the pedicle height. No statistically significant differences (p ≥ 0.12) were observed between manual measurements from oblique MPRs and computerized measurements in 3D, with MAD ± SD of 0.44 ± 0.35 mm, 0.56 ± 0.52 mm and 1.72 ± 1.29 mm for the pedicle width, height and chord length, respectively. The advantage of computerized measurements is that they allow the extraction of additional pedicle morphometric parameters, which are important for preoperative planning of pedicle screw placement, or can be used for population and demographic studies using larger pedicle databases.

Cortical and trabecular bone parameters from HR-Pqct images at the Tibia: a local comparison with synchrotron radiation micro-computed tomography

2013 ◽  
Author(s):  
Agnes Ostertag ◽  
Francoise Peyrin ◽  
Sylvie Fernandez ◽  
Jean-Denis Laredo ◽  
Vernejoul Marie-Christine De ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Synchrotron Radiation ◽  
Trabecular Bone ◽  
Micro Computed Tomography ◽  
Bone Parameters ◽  
Local Comparison

Morphology and Affinities of Ampelocissites Seeds (Vitaceae: Ampelopsis clade) from the Paleogene of Texas, USA

2020 ◽  
Vol 45 (3) ◽  
pp. 478-482
Author(s):  
Steven R. Manchester
Keyword(s):  
Computed Tomography ◽  
Cross Sections ◽  
Seed Coat ◽  
Ct Scanning ◽  
Seed Morphology ◽  
Early Eocene ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Fossil Seeds ◽  
Fossil Genus

Abstract—The type material on which the fossil genus name Ampelocissites was established in 1929 has been reexamined with the aid of X-ray micro-computed tomography (μ-CT) scanning and compared with seeds of extant taxa to assess the relationships of these fossils within the grape family, Vitaceae. The specimens were collected from a sandstone of late Paleocene or early Eocene age. Although originally inferred by Berry to be intermediate in morphology between Ampelocissus and Vitis, the newly revealed details of seed morphology indicate that these seeds represent instead the Ampelopsis clade. Digital cross sections show that the seed coat maintains its thickness over the external surfaces, but diminishes quickly in the ventral infolds. This feature, along with the elliptical chalaza and lack of an apical groove, indicate that Ampelocissites lytlensis Berry probably represents Ampelopsis or Nekemias (rather than Ampelocissus or Vitis) and that the generic name Ampelocissites may be useful for fossil seeds with morphology consistent with the Ampelopsis clade that lack sufficient characters to specify placement within one of these extant genera.

INVESTIGATION OF AUBRITES THROUGH INTEGRATION OF 3D MODAL MINERALOGY WITH X-RAY MICRO-COMPUTED TOMOGRAPHY AND GEOCHEMISTRY

2018 ◽  
Author(s):  
Zoë E. Wilbur ◽  
◽  
Arya Udry ◽  
Arya Udry ◽  
Daniel M. Coleff ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Micro Computed Tomography ◽  
X Ray

scholarly journals Micro-Computed Tomography Analysis of Subchondral Bone Regeneration Using Osteochondral Scaffolds in an Ovine Condyle Model

2021 ◽  
Vol 11 (3) ◽  
pp. 891
Author(s):  
Taylor Flaherty ◽  
Maryam Tamaddon ◽  
Chaozong Liu
Keyword(s):  
Computed Tomography ◽  
Bone Regeneration ◽  
Subchondral Bone ◽  
Volume Ratio ◽  
Bone Volume ◽  
Osteochondral Defects ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Trabecular Thickness ◽  
Osteochondral Scaffold

Osteochondral scaffold technology has emerged as a promising therapy for repairing osteochondral defects. Recent research suggests that seeding osteochondral scaffolds with bone marrow concentrate (BMC) may enhance tissue regeneration. To examine this hypothesis, this study examined subchondral bone regeneration in scaffolds with and without BMC. Ovine stifle condyle models were used for the in vivo study. Two scaffold systems (8 mm diameter and 10 mm thick) with and without BMC were implanted into the femoral condyle, and the tissues were retrieved after six months. The retrieved femoral condyles (with scaffold in) were examined using micro-computed tomography scans (micro-CT), and the micro-CT data were further analysed by ImageJ with respect to trabecular thickness, bone volume to total volume ratio (BV/TV) ratio, and degree of anisotropy of bone. Statistical analysis compared bone regeneration between scaffold groups and sub-set regions. These results were mostly insignificant (p < 0.05), with the exception of bone volume to total volume ratio when comparing scaffold composition and sub-set region. Additional trends in the data were observed. These results suggest that the scaffold composition and addition of BMC did not significantly affect bone regeneration in osteochondral defects after six months. However, this research provides data which may guide the development of future treatments.

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