Kinematic response of lumbar functional spinal units to axial torsion with and without superimposed compression and flexion/extension.
Eur Spine J
; 13(6): 560-6, 2004 Oct.
Article
en En
| MEDLINE
| ID: mdl-15133723
ABSTRACT
Experimental data suggest that lumbar torsion contributes to lumbar disc degenerative changes, such as instability, spondylolisthesis and spinal canal stenosis. However, some basic mechanical characteristics of the lumbar spine under torsional loading have not yet been reported in detail. For example, the function of the facet joints under combined mechanical loads such as torsion with superimposed flexion or extension postures is an area of interest about which little biomechanical data have been reported. In this study, the kinematic response to axial torsion with superimposed axial compression (200 N), compression-flexion (3 and 6 Nm) and compression-extension (3 and 6 Nm) was investigated in 10 cadaveric lumbar functional spinal units. Range of motion (ROM), and helical axes of motion (HAM), were analyzed. There was no difference in ROM between no preload, pure compressive and flexion-compression preload conditions. The ROM was significantly reduced by both extension-compression preload conditions (11% reduction for 3 Nm and 19% reduction for 6 Nm of extension) compared to the pure compressive preload. For no preload, the average HAM position in the transverse plane of the intervertebral disc was near the posteriormost part of the disc and located laterally on the side contralateral to the applied torsional moment. In the transverse plane, the HAM position showed a discrete trend towards the posterior part of the specimens during extension. Kinematic data were visualized using computer animation techniques and CT-based reconstructions of the respective specimens. This information may be used for identifying and characterizing physiologic and pathologic motion and for specifying conservative and surgical treatment concepts and, thus, may find application to identifying indications for spinal fusion or in evaluating the effect of future semi-flexible instrumentation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vértebras Lumbares
Tipo de estudio:
Prognostic_studies
Límite:
Adult
/
Animals
/
Humans
/
Middle aged
Idioma:
En
Revista:
Eur Spine J
Asunto de la revista:
ORTOPEDIA
Año:
2004
Tipo del documento:
Article
País de afiliación:
Alemania