Dynamic Effects on the Lumbar Spinal Canal

Willén, Jan; Danielson, Barbro; Gaulitz, Arne; Niklason, Thomas; Schönström, Nils; Hansson, Tommy

doi:10.1097/00007632-199712150-00021

Cited by 178 publications

(37 citation statements)

References 12 publications

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“…This study confirmed what several other studies already have shown, that the available space within the lumbar spinal canal varies depending on the loading conditions of the spine [2,12,17]. By quantifying separately each structure's contribution to the reduction of the size of the spinal canal in the unloaded and loaded spines (Fig.…”

Section: Discussionsupporting

confidence: 90%

“…Axial loading of the spine Axial loading of the spine was performed using a non magnetic compression device and a harness (DynaWell, DynaMed AB, Stockholm, Sweden) [17]. When loaded the patient was lying supine with extended hips and knees.…”

Section: Methodsmentioning

confidence: 99%

“…Since the diagnostic MRI or CT examinations of the spine, in suspected spinal stenosis, usually are performed in the supine patient, the loading conditions differ from those known to elicit the symptoms in the stenotic spine. To achieve more realistic loading conditions during imaging of the spine special devices have been developed [1,2,16,17]. By applying an axial spinal load corresponding to 50% of the body weight during the MRI or CT examinations a further constriction of the cauda was noted in quite many patients with suspected spinal stenosis [1,16].…”

Section: Introductionmentioning

confidence: 99%

“…The contribution of different structures, e.g. the disc or the ligamentum flavum to the load induced constriction of the spinal canal and the dural sac was never determined [2,16,17].…”

Section: Introductionmentioning

confidence: 99%

“…The degenerated intervertebral disc has usually been regarded as the structure contributing mostly to load induced, dynamic constriction of the cauda and in such away also to the typical load and activity-related symptoms of spinal stenosis [1,12,17].…”

Section: Introductionmentioning

confidence: 99%

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The narrowing of the lumbar spinal canal during loaded MRI: the effects of the disc and ligamentum flavum

et al. 2009

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Load and activity changes of the spine typically cause symptoms of nerve root compression in subjects with spinal stenosis. Protrusion of the intervertebral disc has been regarded as the main cause of the compression. The objective was to determine the changes in the size of the lumbar spinal canal and especially those caused by the ligamentum flavum and the disc during loaded MRI. For this purpose an interventional clinical study on consecutive patients was made. The lumbar spines in 24 supine patients were examined with MRI: first without any external load and then with an axial load corresponding to half the body weight. The effect of the load was determined through the cross-sectional areas of the spinal canal and the ligamentum flavum, the thickness of ligamentum flavum, the posterior bulge of the disc and the intervertebral angle. External load decreased the size of the spinal canal. Bulging of the ligamentum flavum contributed to between 50 and 85% of the spinal canal narrowing. It was concluded that the ligamentum flavum, not the disc had a dominating role for the load induced narrowing of the lumbar spinal canal, a finding that can improve the understanding of the patho-physiology in spinal stenosis.

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Section: Discussionsupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The contribution of different structures, e.g. the disc or the ligamentum flavum to the load induced constriction of the spinal canal and the dural sac was never determined [2,16,17].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The narrowing of the lumbar spinal canal during loaded MRI: the effects of the disc and ligamentum flavum

et al. 2009

Self Cite

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Probabilistic evaluation of the material properties of the in vivo subject‐specific articular surface using a computational model

et al. 2016

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This article used probabilistic analysis to evaluate material properties of the in vivo subject-specific tibiofemoral (TF) joint model. Sensitivity analysis, based on a Monte Carlo (MC) method, was performed using a subject-specific finite element (FE) model generated from in vivo computed tomography (CT) and magnetic resonance imaging (MRI) data, subjected to two different loading conditions. Specifically, the effects of inherent uncertainty in ligament stiffness, horn attachment stiffness, and articular surface material properties were assessed using multifactorial global sensitivity analysis. The MRI images were taken before and after axial compression, and when the flexion condition had been maintained at up to 90 degree flexion in the subject-specific knee joint. The loading conditions of the probabilistic subject-specific FE model (axial compression and 90 degree flexion) were similar to the MRI acquisition setup. We were able to detect the influence of material parameters while maintaining the potential effect of parametric interactions. Throughout the in silico property optimization, a subject-specific FE model was used and less sensitive parameters were eliminated in the global sensitivity method. Soft tissue material properties were estimated using an optimization procedure that involved the minimization of the differences between the kinematics predicted by the subject-specific model and those obtained through in vivo subject-specific data. The results of this approach suggest that the articular surface mechanical properties could be found by using in vivo measurements, which clarifies the valuable tool for future subject-specific studies related to TF joint scaffolds, allografts and biologics. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1390-1400, 2017.

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Functional MRI of the lumbar spine in erect position in a superconducting open‐configuration MR system: Preliminary results

Zamani

Moriarty

Hsu

et al. 1998

Magnetic Resonance Imaging

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The purpose of this study was to determine the feasibility of obtaining, and findings in, functional MRI of the lumbar spine in an erect position and with flexion and extension. Thirty subjects (including 5 volunteers) were imaged in a sitting position and while performing flexion and extension. The alternations in posterior disk margin, size of neural foramina, and central canal were evaluated. In addition, routine supine imaging was accomplished in 15 of these subjects. The foraminal size and posterior disk margins did not change appreciably from supine to upright position. With extension, there was an increased disk bulge in 27% of disks (40% of those with desiccation). Central canal size (50%) and foraminal size (27%) decreased with extension, especially at levels with disk desiccation. Images obtained with our open-configuration MR unit were diagnostically adequate, although of inferior quality compared with those obtained with a conventional unit. Our preliminary results show the feasibility of obtaining diagnostic images of the erect lumbar spine with flexion and extension. The results are in agreement with those obtained with cadaveric studies. The utility of this method in diagnostic imaging of patients with low back pain remains to be determined.

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Dynamic Effects on the Lumbar Spinal Canal

Cited by 178 publications

References 12 publications

The narrowing of the lumbar spinal canal during loaded MRI: the effects of the disc and ligamentum flavum

The narrowing of the lumbar spinal canal during loaded MRI: the effects of the disc and ligamentum flavum

Probabilistic evaluation of the material properties of the in vivo subject‐specific articular surface using a computational model

Functional MRI of the lumbar spine in erect position in a superconducting open‐configuration MR system: Preliminary results

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