Matches in SemOpenAlex for { <https://semopenalex.org/work/W2344762227> ?p ?o ?g. }
Showing items 1 to 75 of
75
with 100 items per page.
- W2344762227 endingPage "447" @default.
- W2344762227 startingPage "447" @default.
- W2344762227 abstract "Introduction Sagittal balance is a combination of a balance function (T1 maintained vertically over S1) that partially constrains the spine, the passive constraints provided by soft tissues and the active constraints – muscle force and gravity. Normal standing posture is likely to be the posture of minimum muscle activity and soft tissue energy. Observed deviation from this position would require muscle action. A mathematical model describing spinal balance without muscle activity is described.Methods The spine was modeled as a series of articulations between the hip and T1 that were controlled by a third degree polynomial ‘spring’ function that approximates the force displacement curves as measured by Panjabi et al. T1 was constrained to remain over S1. Geometric data imported from the erect radiograph of a 34 female without back pain was used to set the zero point for the stiffness functions. All spring functions except the hip function were identical. The system was then perturbed by changing the rest disc space (or hip) angles. An initial smoothing function was used to ‘distribute’ this perturbation amongst several adjacent vertebrae as a guess. The model then minimized the total soft tissue energy to find the new position by treating the system as a series of damped rotational spring – mass constructs. Minimization was achieved using Euler’s method to solve a system of second order nonlinear ordinary differential equations. The iterations were run until oscillations ceased. The model was then perturbed by creating a series of kyphotic deformities at multiple levels and the results were observed.Results Most perturbations converged to a minimum solution almost instantly. With the hip fixed, it was found that kyphotic deformities in the lower and mid lumbar spine led to compensatory lordosis at most other levels – particularly at the apex of the thoracic kyphosis. The spine tended to straighten and lengthen (possibly causing a rise in the centre of mass of the body). This tendency was substantially mitigated by allowing the hip joint to move. By trial and error, a spring function with of one tenth of the stiffness allowed the centre of gravity to move minimally and the compensatory lordosis occurred at segments closer to the induced kyphosis. When an apical thoracic kyphosis was applied with a fixed hip, the spine shortened with compensation being mostly by lordosis in the upper lumbar spine. When the hip was allowed to flex the tendency was for some of the compensation to occur at hip and for the spine to shorten further. The compensatory lordosis that developed at the level above an induced lumbar kyphosis could be partially corrected by applying a flexion moment. However as there is no muscle that is capable of applying such a moment over a single segment an alternative approach suggested that the hyperlordosis could be reduced by applying an extension moment to multiple segments above the hyperlordotic level.Discussion Sagittal Spinal balance is complex. A minimum energy stiffness model may lead to further understanding of spinal balance. The prototype model suggests that the hip joint may have a role in preventing excessive lengthening (with a rise in the centre of gravity) of the spine. The model predicts extensor muscle contraction more than one level above a lumbar kyphosis." @default.
- W2344762227 created "2016-06-24" @default.
- W2344762227 creator A5027228166 @default.
- W2344762227 creator A5048293011 @default.
- W2344762227 date "2006-10-01" @default.
- W2344762227 modified "2023-09-27" @default.
- W2344762227 title "A MINIMUM ENERGY STIFFNESS MODEL OF SPINAL SAGITTAL BALANCE: FEASABILTY AND INITIAL RESULTS" @default.
- W2344762227 hasPublicationYear "2006" @default.
- W2344762227 type Work @default.
- W2344762227 sameAs 2344762227 @default.
- W2344762227 citedByCount "0" @default.
- W2344762227 crossrefType "journal-article" @default.
- W2344762227 hasAuthorship W2344762227A5027228166 @default.
- W2344762227 hasAuthorship W2344762227A5048293011 @default.
- W2344762227 hasConcept C105702510 @default.
- W2344762227 hasConcept C11210021 @default.
- W2344762227 hasConcept C121332964 @default.
- W2344762227 hasConcept C127413603 @default.
- W2344762227 hasConcept C134306372 @default.
- W2344762227 hasConcept C154945302 @default.
- W2344762227 hasConcept C158622935 @default.
- W2344762227 hasConcept C178910020 @default.
- W2344762227 hasConcept C2775924081 @default.
- W2344762227 hasConcept C2779372316 @default.
- W2344762227 hasConcept C33923547 @default.
- W2344762227 hasConcept C41008148 @default.
- W2344762227 hasConcept C47446073 @default.
- W2344762227 hasConcept C62520636 @default.
- W2344762227 hasConcept C66938386 @default.
- W2344762227 hasConcept C71924100 @default.
- W2344762227 hasConceptScore W2344762227C105702510 @default.
- W2344762227 hasConceptScore W2344762227C11210021 @default.
- W2344762227 hasConceptScore W2344762227C121332964 @default.
- W2344762227 hasConceptScore W2344762227C127413603 @default.
- W2344762227 hasConceptScore W2344762227C134306372 @default.
- W2344762227 hasConceptScore W2344762227C154945302 @default.
- W2344762227 hasConceptScore W2344762227C158622935 @default.
- W2344762227 hasConceptScore W2344762227C178910020 @default.
- W2344762227 hasConceptScore W2344762227C2775924081 @default.
- W2344762227 hasConceptScore W2344762227C2779372316 @default.
- W2344762227 hasConceptScore W2344762227C33923547 @default.
- W2344762227 hasConceptScore W2344762227C41008148 @default.
- W2344762227 hasConceptScore W2344762227C47446073 @default.
- W2344762227 hasConceptScore W2344762227C62520636 @default.
- W2344762227 hasConceptScore W2344762227C66938386 @default.
- W2344762227 hasConceptScore W2344762227C71924100 @default.
- W2344762227 hasLocation W23447622271 @default.
- W2344762227 hasOpenAccess W2344762227 @default.
- W2344762227 hasPrimaryLocation W23447622271 @default.
- W2344762227 hasRelatedWork W1444614689 @default.
- W2344762227 hasRelatedWork W1908000436 @default.
- W2344762227 hasRelatedWork W1972190560 @default.
- W2344762227 hasRelatedWork W1983214428 @default.
- W2344762227 hasRelatedWork W1994302817 @default.
- W2344762227 hasRelatedWork W2023347418 @default.
- W2344762227 hasRelatedWork W2039584835 @default.
- W2344762227 hasRelatedWork W2048098222 @default.
- W2344762227 hasRelatedWork W2087763593 @default.
- W2344762227 hasRelatedWork W2090779657 @default.
- W2344762227 hasRelatedWork W2095343639 @default.
- W2344762227 hasRelatedWork W2155156138 @default.
- W2344762227 hasRelatedWork W2319285815 @default.
- W2344762227 hasRelatedWork W2506069541 @default.
- W2344762227 hasRelatedWork W2986405904 @default.
- W2344762227 hasRelatedWork W3169041430 @default.
- W2344762227 hasRelatedWork W3178695931 @default.
- W2344762227 hasRelatedWork W817611709 @default.
- W2344762227 hasRelatedWork W2526542702 @default.
- W2344762227 hasRelatedWork W2535358097 @default.
- W2344762227 isParatext "false" @default.
- W2344762227 isRetracted "false" @default.
- W2344762227 magId "2344762227" @default.
- W2344762227 workType "article" @default.