Fatigue Failure in Shear Loading of Porcine Lumbar Spine Segments

Jh, van Dieën; A, van der Veen; Bj, van Royen; Kingma, Idsart

doi:10.1097/01.brs.0000224515.40694.2c

Cited by 22 publications

(29 citation statements)

References 24 publications

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“…Despite the greater anterioposterior forces created by SMT when compared to passive lumbar motion, the magnitudes of forces experienced during SMT are considerably smaller than those reported in previous research that investigated porcine spinal structural failure at 800 N to 8700 N525354. Although the comparison between anterioposterior forces between the current study and previous investigations is limited due to methodological differences, anterioposterior forces created by SMT did not exceed 40 N.…”

Section: Discussioncontrasting

confidence: 82%

Tissue loading created during spinal manipulation in comparison to loading created by passive spinal movements

Funabashi

Kawchuk

Vette

et al. 2016

Sci Rep

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Spinal manipulative therapy (SMT) creates health benefits for some while for others, no benefit or even adverse events. Understanding these differential responses is important to optimize patient care and safety. Toward this, characterizing how loads created by SMT relate to those created by typical motions is fundamental. Using robotic testing, it is now possible to make these comparisons to determine if SMT generates unique loading scenarios. In 12 porcine cadavers, SMT and passive motions were applied to the L3/L4 segment and the resulting kinematics tracked. The L3/L4 segment was removed, mounted in a parallel robot and kinematics of SMT and passive movements replayed robotically. The resulting forces experienced by L3/L4 were collected. Overall, SMT created both significantly greater and smaller loads compared to passive motions, with SMT generating greater anterioposterior peak force (the direction of force application) compared to all passive motions. In some comparisons, SMT did not create significantly different loads in the intact specimen, but did so in specific spinal tissues. Despite methodological differences between studies, SMT forces and loading rates fell below published injury values. Future studies are warranted to understand if loading scenarios unique to SMT confer its differential therapeutic effects.

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Section: Discussioncontrasting

confidence: 82%

Tissue loading created during spinal manipulation in comparison to loading created by passive spinal movements

Funabashi

Kawchuk

Vette

et al. 2016

Sci Rep

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“…Furthermore, we used a single loading cycle. Cyclic loading might, through visco-elastic behavior of the intervertebral disc, shift load to the posterior element [22], thereby possibly enhancing the detrimental effect of laminectomy on torsional strength. In addition, it should be noted that a limitation of our study is that we used only one specific, relatively low deformation rate (3.0°per min), which might have induced some creep behaviour, effectively transferring rotational resistance from soft tissues to bony structures.…”

Section: Discussionmentioning

confidence: 99%

Torsion biomechanics of the spine following lumbar laminectomy: a human cadaver study

et al. 2013

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Purpose Lumbar laminectomy affects spinal stability in shear loading. However, the effects of laminectomy on torsion biomechanics are unknown. The purpose of this study was to investigate the effect of laminectomy on torsion stiffness and torsion strength of lumbar spinal segments following laminectomy and whether these biomechanical parameters are affected by disc degeneration and bone mineral density (BMD). Methods Ten human cadaveric lumbar spines were obtained (age 75.5, range 59-88). Disc degeneration (MRI) and BMD (DXA) were assessed. Disc degeneration was classified according to Pfirrmann and dichotomized in mild or severe. BMD was defined as high BMD (Cmedian BMD) or low BMD (\median BMD). Laminectomy was performed either on L2 (59) or L4 (59). Twenty motion segments (L2-L3 and L4-L5) were isolated. The effects of laminectomy, disc degeneration and BMD on torsion stiffness (TS) and torsion moments to failure (TMF) were studied.Results Load-displacement curves showed a typical bi-phasic pattern with an early torsion stiffness (ETS), late torsion stiffness (LTS) and a TMF. Following laminectomy, ETS decreased 34.1 % (p \ 0.001), LTS decreased 30.1 % (p = 0.027) and TMF decreased 17.6 % (p = 0.041). Disc degeneration (p \ 0.001) and its interaction with laminectomy (p \ 0.031) did significantly affect ETS. In the mildly degenerated group, ETS decreased 19.7 % from 7.6 Nm/degree (6.4-8.4) to 6.1 Nm/degree (1.5-10.3) following laminectomy. In the severely degenerated group, ETS decreased 22.3 % from 12.1 Nm/degree (4.6-21.9) to 9.4 Nm/degree (5.6-14.3) following laminectomy. In segments with low BMD, TMF was 40.7 % (p \ 0.001) lower than segments with high BMD [34.9 Nm (range 23.7-51.2) versus 58.9 Nm (range 43.8-79.2)]. Conclusions Laminectomy affects both torsion stiffness and torsion load to failure. In addition, torsional strength is strongly affected by BMD whereas disc degeneration affects torsional stiffness. Assessment of disc degeneration and BMD pre-operatively improves the understanding of the biomechanical effects of a lumbar laminectomy.

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“…Por este motivo que somente a rigidez em compressão foi avaliada neste estudo. Os resultados dos testes em compressão axial foram semelhantes aos encontrados na literatura 15,18 . Não foram encontrados falhas ou quebras do material de instrumentação utilizado.…”

Section: Discussionunclassified

Estudo biomecânico da fixação pedicular curta na fratura-explosão toracolombar

et al. 2011

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RESUMOObjetivo: Comparar a rigidez biomecânica entre a coluna toracolombar intacta, a coluna com fratura explosão e a coluna com fratura explosão associada à fixação pedicular curta em suínos. Métodos: 30 amostras de coluna toracolombar (T11-L3) de suínos foram divididas em três grupos com 10 amostras cada. O Grupo 1 representava a coluna intacta, o Grupo 2 representava a coluna com fratura explosão e o Grupo 3 a fratura explosão associada à fixação pedicular curta. Foi realizado o corte ósseo em "V" do terço médio do corpo vertebral comprometendo a coluna anterior e média de L1 para simular a fratura explosão. No Grupo 3 foi realizada a fixação pedicular com Pinos de Schanz. Os grupos foram submetidos ao teste biomecânico em compressão axial controlada. Os parâmetros de carga (N) e deslocamento (mm) eram gerados em um gráfico instantâneo e a rigidez (N/mm) foi determinada. O teste era interrompido quando ocorria uma queda súbita na curva no gráfico indicando falência da amostra. Resultados: A rigidez das colunas fraturadas foi 53% menor do que a rigidez das colunas intactas, sendo essa diferença estatisticamente significativa (p < 0,05). A fixação pedicular curta apresentou uma rigidez 50% maior do que a coluna fraturada. Esse aumento foi estatisticamente significativo (p < 0,05). A rigidez da fixação pedicular curta foi 30% menor do que a rigidez das colunas intactas. Essas diferenças foram estatisticamente significativas (p < 0,05). Conclusão: A fixação pedicular curta não é suficiente para restabelecer a rigidez da coluna intacta nos testes biomecânicos in vitro de compressão axial pura em modelos de fratura toracolombar de suínos.

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Fatigue Failure in Shear Loading of Porcine Lumbar Spine Segments

Abstract: Repetitive shear loading can induce failure of porcine spinal segments, likely caused by fracture of the posterior elements, and, although repetitive anterior shear forces can also induce disc damage, this appears not to occur in intact segments, not even when flexed close to maximal.

Cited by 22 publications

References 24 publications

Tissue loading created during spinal manipulation in comparison to loading created by passive spinal movements

Tissue loading created during spinal manipulation in comparison to loading created by passive spinal movements

Torsion biomechanics of the spine following lumbar laminectomy: a human cadaver study

Estudo biomecânico da fixação pedicular curta na fratura-explosão toracolombar

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