Precision measurement of segmental motion from flexion—extension radiographs of the lumbar spine

Frobin, Wolfgang; Brinckmann, Paul; Leivseth, Gunnar; Biggemann, M; Reikerås, O

doi:10.1016/s0268-0033(96)00039-3

Cited by 137 publications

(124 citation statements)

References 22 publications

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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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“…The images were then calibrated with subsequent results being reported in millimeter. Normal values were obtained from literature [6] on radiographs of 61 symptom-free people (between 16 and 57 years of age).…”

Section: Data Collectionmentioning

confidence: 99%

“…A change of dorsoventral intervertebral translation in relation to the change in sagittal rotation angle is small in the healthy spine [6,7]. The small amount of translation between adjacent vertebrae in physiology is the consequence of the migration of the nucleus, which allows a moving axis of rotation during the flexion-extension motion.…”

Section: Introductionmentioning

confidence: 99%

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Effects of lumbar artificial disc design on intervertebral mobility: in vivo comparison between mobile-core and fixed-core

Delécrin

Allain

Beaurain³

et al. 2010

Eur Spine J

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Although in theory, the differences in design between fixed-core and mobile-core prostheses should influence motion restoration, in vivo kinematic differences linked with prosthesis design remained unclear. The aim of this study was to investigate the rationale that the mobilecore design seems more likely to restore physiological motion since the translation of the core could help to mimic the kinematic effects of the natural nucleus. In vivo intervertebral motion characteristics of levels implanted with the mobile-core prosthesis were compared with untreated levels of the same population, levels treated by a fixed-core prosthesis, and normal levels (data from literature). Patients had a single-level implantation at L4L5 or L5S1 including 72 levels with a mobile-core prosthesis and 33 levels with a fixed-core prosthesis. Intervertebral mobility characteristics included the range of motion (ROM), the motion distribution between flexion and extension, the prosthesis core translation (CT), and the intervertebral translation (VT). A method adapted to the implanted segments was developed to measure the VT: metal landmarks were used instead of the bony landmarks. The reliability assessment of the VT measurement method showed no difference between three observers (p \ 0.001), a high level of agreement (ICC = 0.908) and an interobserver precision of 0.2 mm. Based on this accurate method, this in vivo study demonstrated that the mobile-core prosthesis replicated physiological VT at L4L5 levels but not at L5S1 levels, and that the fixed-core prosthesis did not replicate physiological VT at any level by increasing VT. As the VT decreased when the CT increased (p \ 0.001) it was proven that the core mobility minimized the VT. Furthermore, some physiologic mechanical behaviors seemed to be maintained: the VT was higher at implanted the L4L5 level than at the implanted L5S1 level, and the CT appeared lower at the L4L5 level than at the L5S1 level. ROM and motion distribution were not different between the mobile-core prosthesis and the fixedcore prosthesis implanted levels. This study validated in vivo the concept that a mobile-core helps to restore some physiological mechanical characteristics of the VT at the implanted L4L5 level, but also showed that the minimizing effect of core mobility on the VT was not sufficient at the L5S1 level.

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An optimization‐based method for prediction of lumbar spine segmental kinematics from the measurements of thorax and pelvic kinematics

Shojaei

Arjmand

Bazrgari

2015

Numer Methods Biomed Eng

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Given measurement difficulties, earlier modeling studies have often used some constant ratios to predict lumbar segmental kinematics from measurements of total lumbar kinematics. Recent imaging studies suggested distribution of lumbar kinematics across its vertebrae changes with trunk rotation, lumbar posture, and presence of load. An optimization-based method is presented and validated in this study to predict segmental kinematics from measured total lumbar kinematics. Specifically, a kinematics-driven biomechanical model of the spine is used in a heuristic optimization procedure to obtain a set of segmental kinematics that, when prescribed to the model, were associated with the minimum value for the sum of squared predicted muscle stresses across all the lower back muscles. Furthermore, spinal loads estimated using the predicted kinematics by the present method were compared with those estimated using constant ratios. Predicted segmental kinematics were in good agreement with those obtained by imaging with an average error of ~10%. Compared with those obtained using constant ratios, predicted spinal loads using segmental kinematics obtained here were in general smaller. In conclusion, the proposed method offers an alternative tool for improving model-based estimates of spinal loads where image-based measurement of lumbar kinematics is not feasible.

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Precision measurement of segmental motion from flexion—extension radiographs of the lumbar spine

Cited by 137 publications

References 22 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

Effects of lumbar artificial disc design on intervertebral mobility: in vivo comparison between mobile-core and fixed-core

An optimization‐based method for prediction of lumbar spine segmental kinematics from the measurements of thorax and pelvic kinematics

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