Mechanical Process and Growth Cartilages; Essential Factors in the Progression of Scoliosis

Perdriolle, R; Becchetti, S.; Vidal, J; Lopez, P

doi:10.1097/00007632-199303000-00007

Cited by 58 publications

(40 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…White [39] observed the presence of a slight physiological thoracic curve, thus he associated the prime scoliotic lesion with the precarious coronal balance of the spine and consequent asymmetrical loading of vertebrae, which might rotate into the convexity of the curve. Following onset of the initial deformity, it is generally recognized that progressive scoliosis evolves within a selfsustaining biomechanical cycle involving asymmetrical loading of the spine, alteration of vertebral growth ("growth modulation"), development of scoliotic deformities and so on [6,16,22].…”

mentioning

confidence: 99%

“…This principle states that increased pressure on the plate retards growth (Hueter), and conversely reduced pressure accelerates growth (Volkmann) [1,31]. For asymmetrically loaded vertebrae, endplates initially parallel in the frontal plane become wedged in 3D while the vertebrae are rotating in space [4,22,28]. Torsion or shear forces, which are parallel to the plates, essentially alter the direction of growth, with cartilaginous columns leaning under the forces [1,19].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Biomechanical simulations of the spine deformation process in adolescent idiopathic scoliosis from different pathogenesis hypotheses

Villemure

Aubin

Dansereau

et al. 2004

European Spine Journal

View full text Add to dashboard Cite

IntroductionAdolescent idiopathic scoliosis (AIS) is a complex threedimensional (3D) anomaly of the spine involving lateral deviations in the frontal plane, modifications of the sagittal profile, spinal torsion and transverse plane deformations [16,21,23]. There is still no generally accepted scientific theory for its etiology [7,16,21,23]. The pathogenesis of AIS is not clearly defined regarding either how Abstract It is generally recognized that progressive adolescent idiopathic scoliosis (AIS) evolves within a selfsustaining biomechanical process involving asymmetrical growth modulation of vertebrae due to altered spinal load distribution. A biomechanical finite element model of normal thoracic and lumbar spine integrating vertebral growth was used to simulate the progression of spinal deformities over 24 months. Five pathogenesis hypotheses of AIS were represented, using an initial geometrical eccentricity (gravity line imbalance of 3 mm or 2°rotation) at the thoracic apex to trigger the self-sustaining deformation process. For each simulation, regional (thoracic Cobb angle, kyphosis) and local scoliotic descriptors (axial rotation and wedging of the thoracic apical vertebra) were evaluated at each growth cycle. The simulated AIS pathogeneses resulted in the development of different scoliotic deformities. Imbalance of 3 mm in the frontal plane, combined or not with the sagittal plane, resulted in the closest representation of typical scoliotic deformities, with the thoracic Cobb angle progressing up to 39°(26°when a sagittal offset was added). The apical vertebral rotation increased by 7°t owards the convexity of the curve, while the apical wedging increased to 8.5°(7.3°with the sagittal eccentricity) and this deformity evolved towards the vertebral frontal plane. A sole eccentricity in the sagittal plane generated a non-significant frontal plane deformity. Simulations involving an initial rotational shift (2°) in the transverse plane globally produced relatively small and nontypical scoliotic deformations. Overall, the thoracic segment predominantly was sensitive to imbalances in the frontal plane, although unidirectional geometrical eccentricities in different planes produced three-dimensional deformities at the regional and vertebral levels, and their deformities did not cumulate when combined. These results support the hypothesis of a prime lesion involving the precarious balance in the frontal plane, which could concomitantly be associated with a hypokyphotic component. They also suggest that coupling mechanisms are involved in the deformation process.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Biomechanical simulations of the spine deformation process in adolescent idiopathic scoliosis from different pathogenesis hypotheses

Villemure

Aubin

Dansereau

et al. 2004

European Spine Journal

View full text Add to dashboard Cite

show abstract

“…Cavallo et al [11] found that over a quarter of the female students in a fourth grade group carried a backpack of greater than 15 % BW, while Negrini and Carabalona [7] reported a mean backpack load of over 20 % BW. The daily loads applied by schoolbags are of particular concern in patients with AIS as abnormal external loading has been suggested as one of the possible factors that may affect the growth of the spine and exacerbate the scoliotic deformity [2].…”

Section: Discussionmentioning

confidence: 99%

“…Stokes et al [1] and other authors [2] have suggested the ''vicious cycle'' theory of scoliosis progression which proposes that scoliosis causes loading of the spine that is asymmetric in the coronal plane, and that vertebral growth and disc remodeling respond to the chronic presence of these asymmetric forces. External factors, like the schoolbag, act additionally as a burden on the balance mechanism and may have adverse effects on balance control.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Loading rate patterns in scoliotic children during gait: the impact of the schoolbag carriage and the importance of its position

et al. 2012

View full text Add to dashboard Cite

Purpose Concerns have been raised regarding the effects of schoolbag carriage on adolescent schoolchildren and particularly those with a pre-existing spinal deformity. The purpose of this study was to determine the effect of school backpack loads in scoliotic and healthy school-age children during walking, in terms of peak vertical ground reaction forces and loading rates. We hypothesized that walking with a loaded backpack would have a greater effect on gait kinetics of scoliotic compared to healthy. Methods Eight children with idiopathic scoliosis and eight healthy children were assessed. Kinetic data were collected using two AMTI OR6-7 force-plates, while the subjects walked freely along a 6-m walkway under three walking conditions: (1) without a schoolbag, (2) carrying a schoolbag bilaterally (over both shoulders-symmetrical load) and (3) carrying a schoolbag unilaterally (over each shoulder-asymmetrical load). Kinetic data were collected and four parameters were calculated; peak ground reaction force at the first maximum force peak (F1), time needed to reach F1 (T1), loading rate of F1 (LRF1) and total contact time (T2). ResultsWe found no significant differences between the scoliotic and healthy children for any of the kinetic variables examined. In addition, the position of the bag did not seem to have any effect on loading rate. Conclusions The results of this study indicate that in terms of kinetic parameters during normal gait, the schoolbag load (symmetrical or asymmetrical) does not have a different effect on children with mild adolescent idiopathic scoliosis compared to normal controls.

show abstract

Mechanical modulation of growth for the correction of vertebral wedge deformities

Mente

Aronsson

Stokes

et al. 1999

Journal Orthopaedic Research

View full text Add to dashboard Cite

This study tested the following hypotheses: (a) a vertebral wedge deformity created by chronic static asymmetrical loading will be corrected by reversal of the load asymmetry; (b) a vertebral wedge deformity created by chronic static asymmetrical loading will remain if the load is simply removed; and (c) vertebral longitudinal growth rates, altered by chronic static loading, will return to normal after removal of the load. An external fixator was used to impose an angular deformity (Cobb angle of 30 degrees) and an axial compression force (60% body weight) on the ninth caudal (apical) vertebra in two groups of 12 5-week-old Sprague-Dawley rats. This asymmetrical loading was applied to all rats for 4 weeks to create an initial wedge deformity in the apical vertebra. The rats from group I (load reversal) then underwent 1 week of distraction loading followed by 4 weeks of asymmetrical compressive loading with the imposed 30 degree Cobb angle reversed. The rats from group II (load removal) had the apparatus removed and were followed for 5 weeks with no external loading. Weekly radiographs were obtained and serial fluorochrome labels were administered to follow vertebral wedging. After the initial 4-week loading period, the combined average wedge deformity that developed in the apical vertebra of the animals in both groups was 10.7 +/- 4.4 degrees. The group that underwent load reversal showed significant correction of the deformity with the wedging of the apical vertebra decreasing to, on average, 0.1 +/- 1.4 degrees during the 4 weeks of load reversal. Wedging of the apical vertebra in the group that underwent load removal significantly decreased to 7.3 +/- 3.9 degrees during the first week after removal of the load, but no significant changes in wedging occurred after that week. This indicated a return to a normal growth pattern following the removal of the asymmetrically applied loading. The longitudinal growth rate of the apical vertebra also returned to normal following removal of the load. Vertebrae maintained under a load of 60% body weight grew at a rate that was 59.4 +/- 17.0% lower than that of the control vertebrae, whereas after vertebrae were unloaded their growth averaged 102.4 +/- 31.8%. These findings show that a vertebral wedge deformity can be corrected by reversing the load used to create it and that vertebral growth is not permanently affected by applied loading.

show abstract

Mechanical Process and Growth Cartilages; Essential Factors in the Progression of Scoliosis

Cited by 58 publications

References 0 publications

Biomechanical simulations of the spine deformation process in adolescent idiopathic scoliosis from different pathogenesis hypotheses

Biomechanical simulations of the spine deformation process in adolescent idiopathic scoliosis from different pathogenesis hypotheses

Loading rate patterns in scoliotic children during gait: the impact of the schoolbag carriage and the importance of its position

Mechanical modulation of growth for the correction of vertebral wedge deformities

Contact Info

Product

Resources

About