A new laser scanning technique for imaging intervertebral disc displacement and its application to modeling nucleotomy
| Autor: | Lutz Claes, Hendrik Schmidt, Frank Heuer, Hans-Joachim Wilke |
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| Rok vydání: | 2007 |
| Předmět: |
Materials science
Laser scanning Biophysics In Vitro Techniques Models Biological Sensitivity and Specificity Imaging Three-Dimensional Deflection (engineering) Lumbar spine Laser scanner Finite element analysis Validation Disc bulging Combined loading Soft tissue deformation Image Interpretation Computer-Assisted medicine Humans Orthopedics and Sports Medicine Displacement (orthopedic surgery) Computer Simulation Diskectomy Percutaneous Intervertebral Disc Deformation (mechanics) Lasers Reproducibility of Results Intervertebral disc Anatomy Middle Aged 090300 BIOMEDICAL ENGINEERING Finite element method Nucleotomy medicine.anatomical_structure 110600 HUMAN MOVEMENT AND SPORTS SCIENCE Surgery Computer-Assisted Intervertebral Disc Displacement Biomedical engineering |
| Zdroj: | Clinical Biomechanics |
| ISSN: | 0268-0033 |
| Popis: | Background Nucleotomy is a standard procedure for treating disc prolapse. It can reduce intervertebral disc height, flattening and displacing the disc, which could lead to a painful narrowing of the foramina due to nerve root compression. The purpose of this study was to investigate the disc displacement of a complete spinal segment with and without nucleotomy. We hypothesized that a nucleotomy under a certain load combination might amplify disc displacement. Methods A laser scanner was developed for recording three-dimensional disc displacement of six loaded L4-5 specimens for three conditions: intact, disc with vertebral bodies and subsequent nucleotomy. Specimens were exposed to pure moments of 7.5 N m in the three principal anatomical directions. Disc displacement was obtained at maximal deflection. A finite element model was validated and subsequently utilized to determine disc displacement. The task of the finite element model was to provide supplemental data for the posterolateral region, which could not be measured from intact specimens. Findings Disc displacement measurements of intact specimens were limited to the anterior part of discs, whereas the finite element model was able to provide the missing data of the dorsal disc region. The simulation of load combinations showed that the highest disc displacement was 1.9 mm at the lateral or posterolateral region. The nucleotomy increased the disc displacement up to 2.1 mm, whereas the displacement zenith migrated posterolaterally. Interpretation These results could be a possible explanation for disadvantages of nucleotomy as a treatment. With the methodology presented here, we would be able to assess the performance of nucleus implants by determining the disc displacement map. This could also give us appropriate information of the annular deformation, which is needed for the development of motion preserving implants. |
| Databáze: | OpenAIRE |
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