Role of Ligaments and Facets in Lumbar Spinal Stability

Sharma, Manoj Kumar; Langrana, Noshir A.; Rodríguez, Javier

doi:10.1097/00007632-199504150-00003

Cited by 382 publications

(229 citation statements)

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“…The acute traumatic cervical facet dislocation is most likely to be complete translation of the inferior facet of the superior vertebra to the most anterior margin of the superior facet of the inferior vertebra in the sagittal plane. Sharma et al [15] have demonstrated that the flexion moment of anterior shear loading moves the facets away from each other in the lumbar spine. More horizontally oriented superior facets in the lower cervical spine may predispose to facet translational or rotational instability if the hyperflexion/distraction motion and anterior shear forces are applied on the cervical spine.…”

Section: Discussionmentioning

confidence: 99%

Morphometric analyses of the cervical superior facets and implications for facet dislocation

Ebraheim

Patil

Liu

et al. 2006

International Orthopaedics (SICO

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The articular facets of the cervical spine have been well addressed; however, little information is available on the relationship of the superior facets of the cervical spine to traumatic dislocation in the literature. Morphometric analyses of the superior facets of 30 dried cervical spines from C3 to C7 were performed to determine any morphological differences. The angle of the superior facet with respect to the transverse plane was also measured on computed tomography (CT) scans of 30 patients having neck injury without fracture/dislocation. The vertical and surface lengths of the superior facet were significantly lower (P<0.01) at C6-C7 levels than at C3-5 levels. The anteroposterior diameter of the superior facet was smaller (P<0.05) at C6 and C7 levels compared to C3-5 levels. Although the superior facet joint surface is in a more coronal orientation in lower cervical vertebrae, the inclination of the superior facet is more horizontal relative to the transverse plane when measured in vivo. A combination of lower height, smaller anteroposterior diameter of the superior facet, and a more horizontally oriented superior facet at C6 and C7 levels in vivo may explain the predilection of translation relative to one another in the lower cervical spine. Résumé Les facettes articulaires de la colonne cervicale sont bien analysées cependant une meilleure connaissance des relations de l'articulaire supérieure lors des traumatismes avec luxations de la colonne dans la littérature est possible. L'analyse morphométrique de l'articulaire supér-ieure a été analysée sur 30 colonnes cervicales de cadavres, de C3 à C7, de façon à analyser les différences morphologiques. L'angle supérieur de l'articulaire a été mesuré sur le scanner de 30 patients ayant présenté un traumatisme cervical sans fracture, ni luxation. Les dimensions verticales et les surfaces de l'articulaire supérieure sont, significativement, moins importantes au niveau C6 et C7 qu'au niveau C3 à C5 (p<0.01). Le diamètre antéropostér-ieur de l'articulaire supérieure est également plus petit au niveau de C6 C7 qu'au niveau de C3 C5 (p<0.05). De la même façon, l'articulaire supérieure est dans un plan plus frontal dans la partie basse de la colonne. L'inclinaison de cette articulaire est, de même, plus horizontale par rapport au plan transversal, mesure in vivo. La combinaison de tous ces facteurs : dimensions moins importantes, petits diamètres, antéropostérieur et facettes supérieures de l'articulaire plus horizontale en C6 C7, expliquent la fréquence des translations relatives possibles des vertèbres dans la partie basse de la colonne et donc la fragilité de cette zone.

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Section: Discussionmentioning

confidence: 99%

Morphometric analyses of the cervical superior facets and implications for facet dislocation

Ebraheim

Patil

Liu

et al. 2006

International Orthopaedics (SICO

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“…They furthermore protect the disc from excessive rotational strain and anterior shear forces [2,15]. It therefore has been argued that more sagittal alignment of the joint leads to anterior gliding due to a reduced resistance to anterior shear forces [10,24]. These forces are particularly large in the lower two segments of the lumbar spine, as lordosis and horizontal vertebral tilt increase.…”

Section: Discussionmentioning

confidence: 99%

“…The facet joints play a critical role in maintaining stability of the lumbar spine by sharing load in compression and extension, and protecting the disc from excessive shear and rotational forces [1,13,24]. Determined by their spatial orientation, they also guide motion between two adjacent vertebrae.…”

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confidence: 99%

Facet joint remodeling in degenerative spondylolisthesis: an investigation of joint orientation and tropism

Berlemann

Jeszenszky

Bühler

et al. 1998

European Spine Journal

102

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IntroductionSeveral studies have attempted to define etiological factors for the development of degenerative spondylolisthesis (DS), and the orientation of lumbar facet angles relative to the transverse plane has been a major focus of interest. The facet joints play a critical role in maintaining stability of the lumbar spine by sharing load in compression and extension, and protecting the disc from excessive shear and rotational forces [1,13,24]. Determined by their spatial orientation, they also guide motion between two adjacent vertebrae. Their oblique orientation in the lumbar spine allows flexion, extension, and lateral bending, but only a small amount of axial rotation [27].It has been shown that in patients with DS, the facet joints are significantly more sagittally oriented, thus allowing the superior vertebra to glide anteriorly. Individuals with sagittally oriented facet joints have therefore been regarded as candidates for DS [23]. However, it is not clear whether this more pronounced sagittal orientation of the facet joint represents a pre-existing morphology or whether it has to be considered a result of secondary remodeling.Facet joint asymmetry (tropism) has been claimed to be related to disc herniation and degenerative disc disease due to rotational instability of the spinal segment [6,8,20]. Whether facet joint tropism plays a role in the development of DS, however, has not been investigated.The present study analyzed facet joint orientation in the transverse plane in patients with DS and compared this to patients with no evidence of ventrolisthesis from three different age groups. The working hypothesis was that if the more sagittal orientation in DS was a pre-existing anatomical feature, it then should be possible to identify a younger patient group being "at risk" for the development of DS later in life. The incidence of facet joint tropism in the different groups was also investigated.Abstract This study analyzed transverse facet joint angulations at the three lower lumbar levels in 132 patients assigned to one of four groups. Group A comprised 23 patients with degenerative spondylolisthesis (DS) at the level L4-5, group B comprised 40 patients above the age of 50 years, group C comprised 38 patients aged between 35 and 50 years, and group D comprised 31 patients under the age of 35 years. Groups B, C, and D had no evidence of DS. Measurements were taken from hard copies of axial MR or CT images. The transverse plane of facet joints was more sagittally oriented in group A than in any other group. This difference was highly significant at the L4-5 level. The incidence of more sagittally oriented L4-5 facet joints was also significantly higher only in group A. The incidence of facet joint tropism, however, was not different in group A. These results support the view that the pronounced sagittal alignment of facet joints in patients with DS represents a secondary remodeling rather than a pre-existing morphology. Facet joint asymmetry does not seem to play a major role in the development of DS.

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“…Fibres of annulus fibrosus Non-linear and dependent on the distance from the disc centre Spring [32] Ligaments Non-linear Spring [31,46] Cartilage of facet joint Soft contact [47] Eur Spine J (2010) 19:1585-1595 1587 rotation, a follower load of 500 N and a corresponding moment of 7.5 Nm were chosen. Walking causes an axial force which is about 30% higher than that for standing [38].…”

Section: Loadingmentioning

confidence: 99%

A probabilistic finite element analysis of the stresses in the augmented vertebral body after vertebroplasty

et al. 2010

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Fractured vertebral bodies are often stabilized by vertebroplasty. Several parameters, including fracture type, cement filling shape, cement volume, elastic moduli of cement, cancellous bone and fractured region, may all affect the stresses in the augmented vertebral body and in bone cement. The aim of this study was to determine numerically the effects of these input parameters on the stresses caused. In a probabilistic finite element study, an osteoligamentous model of the lumbar spine was employed. Seven input parameters were simultaneously and randomly varied within appropriate limits for [110 combinations thereof. The maximum von Mises stresses in cancellous and cortical bone of the treated vertebral body L3 and in bone cement were calculated. The loading cases standing, flexion, extension, lateral bending, axial rotation and walking were simulated. In a subsequent sensitivity analysis, the coefficients of correlation and determination of the input parameters on the von Mises stresses were calculated. The loading case has a strong influence on the maximum von Mises stress. In cancellous bone, the median value of the maximum von Mises stresses for the different input parameter combinations varied between 1.5 (standing) and 4.5 MPa (flexion). The ranges of the stresses are large for all loading cases studied. Depending on the loading case, up to 69% of the maximum stress variation could be explained by the seven input parameters. The fracture shape and the elastic modulus of the fractured region have the highest influence. In cortical bone, the median values of the maximum von Mises stresses varied between 31.1 (standing) and 61.8 MPa (flexion). The seven input parameters could explain up to 80% of the stress variation here. It is the fracture shape, which has always the highest influence on the stress variation. In bone cement, the median value of the maximum von Mises stresses varied between 3.8 (standing) and 12.7 MPa (flexion). Up to 75% of the maximum stress variation in cement could be explained by the seven input parameters. Fracture shape, and the elastic moduli of bone cement and of the fracture region are those input parameters with the highest influence on the stress variation. In the model with no fracture, the maximum von Mises stresses are generally low. The present probabilistic and sensitivity study clearly showed that in vertebroplasty the maximum stresses in the augmented vertebral body and in bone cement depend mainly on the loading case and fracture shape. Elastic moduli of cement, fracture region and cancellous bone as well as cement volume have sometimes a moderate effect while number and symmetry of cement plugs have virtually no effect on the maximum stresses.

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Role of Ligaments and Facets in Lumbar Spinal Stability

Cited by 382 publications

References 0 publications

Morphometric analyses of the cervical superior facets and implications for facet dislocation

Morphometric analyses of the cervical superior facets and implications for facet dislocation

Facet joint remodeling in degenerative spondylolisthesis: an investigation of joint orientation and tropism

A probabilistic finite element analysis of the stresses in the augmented vertebral body after vertebroplasty

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