Functional Radiographic Diagnosis of the Cervical Spine: Flexion/Extension

Dvořák, Jiří; Froehlich, D.; Penning, L; Baumgartner, H.; Panjabi, M M

doi:10.1097/00007632-198807000-00007

Cited by 276 publications

(202 citation statements)

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“…Moreover, although these proportions were assumed constant during the entire lifting tasks, such may not necessarily be true in vivo as the relative demand at different levels could vary during lifting. These relative ratios were taken from data obtained in static measurements [29,34,76,79], which have also been used in previous dynamic studies [70,82,83] in order to evaluate the contribution of passive tissue in offsetting external load. To prescribe measured rotations in the model, kinematics data of one typical subject rather than the mean of all subjects were considered.…”

Section: Methodological Issuesmentioning

confidence: 99%

“…The total lumbar rotation, calculated as the difference between the foregoing two rotations, was subsequently partitioned in between various segments based on values reported in earlier investigations [3,29,34,76,79,91,104]. Relative proportions of~7, 12,15,22,27 and 17% were used to partition the lumbar rotation between various motion segments from T12 to L5 levels, respectively.…”

Section: Prescribed Posturesmentioning

confidence: 99%

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Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

2006

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Despite the well-recognized role of lifting in back injuries, the relative biomechanical merits of squat versus stoop lifting remain controversial. In vivo kinematics measurements and model studies are combined to estimate trunk muscle forces and internal spinal loads under dynamic squat and stoop lifts with and without load in hands. Measurements were performed on healthy subjects to collect segmental rotations during lifts needed as input data in subsequent model studies. The model accounted for nonlinear properties of the ligamentous spine, wrapping of thoracic extensor muscles to take curved paths in flexion and trunk dynamic characteristics (inertia and damping) while subject to measured kinematics and gravity/ external loads. A dynamic kinematics-driven approach was employed accounting for the spinal synergy by simultaneous consideration of passive structures and muscle forces under given posture and loads. Results satisfied kinematics and dynamic equilibrium conditions at all levels and directions. Net moments, muscle forces at different levels, passive (muscle or ligamentous) forces and internal compression/shear forces were larger in stoop lifts than in squat ones. These were due to significantly larger thorax, lumbar and pelvis rotations in stoop lifts. For the relatively slow lifting tasks performed in this study with the lowering and lifting phases each lasting~2 s, the effect of inertia and damping was not, in general, important. Moreover, posterior shift in the position of the external load in stoop lift reaching the same lever arm with respect to the S1 as that in squat lift did not influence the conclusion of this study on the merits of squat lifts over stoop ones. Results, for the tasks considered, advocate squat lifting over stoop lifting as the technique of choice in reducing net moments, muscle forces and internal spinal loads (i.e., moment, compression and shear force).

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Section: Methodological Issuesmentioning

confidence: 99%

Section: Prescribed Posturesmentioning

confidence: 99%

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

2006

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“…Although standard clinical imaging techniques, especially nuclear magnetic resonance imaging (MRI), allow the detection of discoligamentous injuries [9,13,24,30,31], few biomechanical data exist concerning the significance of the different discoligamentous structures for the load-displacement properties of the cervical spine under physiological loads. Several studies have been carried out to evaluate the load-displacement properties of the normal lower cervical spine in vitro [6,15,17,19,25] and in vivo [2,3,12,20], as well as in different types of artificial defect situations [6,18,26,32]. Variations in the study designs with regard to testing protocol and type of artificial defect make comparison between the different studies difficult.…”

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confidence: 99%

Load-displacement properties of the normal and injured lower cervical spine in vitro

Richter¹,

Wilke

Kluger³

et al. 2000

European Spine Journal

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IntroductionThe discoligamentous structures of the cervical spine are often involved in cervical spine injuries, for example in whiplash injuries. Although standard clinical imaging techniques, especially nuclear magnetic resonance imaging (MRI), allow the detection of discoligamentous injuries [9,13,24,30,31], few biomechanical data exist concerning the significance of the different discoligamentous structures for the load-displacement properties of the cervical spine under physiological loads. Several studies have been carried out to evaluate the load-displacement properties of the normal lower cervical spine in vitro [6,15,17,19,25] and in vivo [2,3,12,20], as well as in different types of artificial defect situations [6,18,26,32]. Variations in the study designs with regard to testing protocol and type of artificial defect make comparison between the different studies difficult. Few studies have tested artificial discoligamentous defects in the lower cervical spine under near-physiological loads [25,26,32].The objective of this study was therefore to evaluate the type and amount of instability caused by injury of different discoligamentous structures of the cervical spine in comparison to the intact cervical spine.Abstract The objective of this study was to determine which discoligamentous structures of the lower cervical spine provide significant stability with regard to different loading conditions. Accordingly, the loaddisplacement properties of the normal and injured lower cervical spine were tested in vitro. Four artificially created stages of increasing discoligamentous instability of the segment C5/6 were compared to the normal C5/6 segment. Six fresh human cadaver spine segments C4-C7 were tested in flexion/extension, axial rotation, and lateral bending using pure moments of ± 2.5 Nm without axial preload. Five conditions were investigated consecutively: (1) the intact functional spinal unit (FSU) C5/6; (2) the FSU C5/6 with the anterior longitudinal ligament and the intertransverse ligaments sectioned; (3) the FSU C5/6 with an additional 10-mm-deep incision of the anterior half of the anulus fibrosus and the disc; (4) the FSU C5/6 with additionally sectioned ligamenta flava as well as interspinous and supraspinous ligaments; (5) the FSU C5/6 with additional capsulotomy of the facet joints. In flexion/extension, significant differences were observed concerning range of motion (ROM) and neutral zone (NZ) for all four stages of instability compared to the intact FSU. In axial rotation, only the stage 4 instability showed a significantly increased ROM and NZ compared to the intact FSU. For lateral bending, no significant differences were observed. Based on these data, we conclude that flexion/extension is the most sensitive load-direction for the tested discoligamentous instabilities.

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“…Thoracic cage movements (main motion rotations and translations) cause specific lumbar spine coupled motion [12,15,18,22,40,43,46,51,52].…”

Section: Discussionmentioning

confidence: 99%

“…The rotational thoracic cage postures (axial, lateral bending, flexion-extension main motions) have been studied for their affects on the lumbar spine (coupled motions), [12,15,24,40,43,46,48,51,52] while the translations (left-right, up-down, forward-backward) of the rib cage have received less attention in the literature [18,22,23,47].…”

mentioning

confidence: 99%

Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images

Harrison

Janik²,

Cailliet

et al. 2006

Eur Spine J

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IntroductionHuman thoracic cage posture has been of interest since ancient times, especially deformities of the rib cage [20,25,35,36,45]. In his classic texts, Breig [8][9][10] showed that human postures can cause adverse mechanical tension on the central nervous system, thus correlating abnormal posture with disease. During the past century, thoracic posture (axial translation) has been associated with the treatment of disc degeneration and prolapse [13,37,50]. Abstract Since thoracic cage posture affects lumbar spine coupling and loads on the spinal tissues and extremities, a scientific analysis of upright posture is needed. Common posture analyzers measure human posture as displacements from a plumb line, while the PosturePrintä claims to measure head, rib cage, and pelvic postures as rotations and translations. In this study, it was decided to evaluate the validity of the PosturePrintä Internet computer system's analysis of thoracic cage postures. In a university biomechanics laboratory, photographs of a mannequin thoracic cage were obtained in different postures on a stand in front of a digital camera. For each mannequin posture, three photographs were obtained (left lateral, right lateral, and AP). The mannequin thoracic cage was placed in 68 different single and combined postures (requiring 204 photographs) in five degrees of freedom: lateral translation (Tx), lateral flexion (Rz), axial rotation (Ry), flexion-extension (Rx), and anteriorposterior translation (Tz). The PosturePrintä system requires 13 reflective markers to be placed on the subject (mannequin) during photography and 16 additional ''click-on'' markers via computer mouse before a set of three photographs is analyzed by the PosturePrintä computer system over the Internet. Errors were the differences between the positioned mannequin and the calculated positions from the computer system. Average absolute value errors were obtained by comparing the exact inputted posture to the PosturePrintä's computed values. Mean and standard deviation of computational errors for sagittal displacements of the thoracic cage were Rx=0.3±0.1°, Tz=1.6±0.7 mm, and for frontal view displacements were Ry=1.2±1.0°, Rz=0.6±0.4°, and Tx=1.5±0.6 mm. The PosturePrintä system is sufficiently accurate in measuring thoracic cage postures in five degrees of freedom on a mannequin indicating the need for a further study on human subjects.

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Functional Radiographic Diagnosis of the Cervical Spine: Flexion/Extension

Cited by 276 publications

References 0 publications

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

Analysis of squat and stoop dynamic liftings: muscle forces and internal spinal loads

Load-displacement properties of the normal and injured lower cervical spine in vitro

Validation of a computer analysis to determine 3-D rotations and translations of the rib cage in upright posture from three 2-D digital images

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