Biomechanical Study and Digital Modeling of Traction Resistance in Posterior Thoracic Implants

Gayet, Louis Etienne; Priès, P.; Hamcha, H.; Clarac, J.-P.; Texereau, Jacques

doi:10.1097/00007632-200204010-00007

Cited by 26 publications

(20 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…By mechanical testing, we found that the 6.0 mm screw had a higher pullout strength than the 5.0 mm screw. These results agree with those reported by Kwok et al, Barber et al, and Gayet et al, [11,26,28].…”

Section: Discussionsupporting

confidence: 94%

Biomechanical Study of the Pullout Resistance in Screws of a Vertebral Fixation System

Fakhouri

Zamarioli

Wichr

et al. 2011

Advances in Mechanical Engineering

View full text Add to dashboard Cite

The purpose of this study was to investigate the effect of varying the outer diameter of screws of a vertebral fixation system by submitting them to mechanical tests and photoelasticity. The pullout mechanical test was performed in 20 swine lumbar vertebrae, divided into two groups based on the screw outer diameter: 5.0 and 6.0 mm. The maximal pullout strengths and stiffness were evaluated. For the photoelasticity, eight models were used and divided into the same groups. The maximal pullout strength was 974.12 ± 144.44 N in the 5.0 mm screws and 1537.42 ± 326.95 N in the 6.0 mm screws (P < 0.001). The stiffness was 418.60 ± 62.58 10 3 N/m in the 5.0 mm screws and 502.12 ± 133.45 10 3 N/m in the 6.0 mm screws (P = 0.09). The mean ± SD shear stress of the 5.0 mm screws was 12.90 ± 1.87 KPa and 11.99 ± 2.01 KPa for the 6.0 mm screws. Thus, the 5.0 mm screw had lower pullout and higher shear stress, suggesting that this screw is more susceptible to loosening.

show abstract

Section: Discussionsupporting

confidence: 94%

Biomechanical Study of the Pullout Resistance in Screws of a Vertebral Fixation System

Fakhouri

Zamarioli

Wichr

et al. 2011

Advances in Mechanical Engineering

View full text Add to dashboard Cite

show abstract

“…Although offset hooks may enhance the pedicle screw construct when placed at the adjacent level, extending the fusion an additional level might also be considered. Gayet et al [6] investigated the traction resistance and mode of failure of posterior thoracic implants in single human motion segments. Pedicular-laminar traction resulted in fracture at the base of the pedicles.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical evaluation of a new fixation device for the thoracic spine

et al. 2009

View full text Add to dashboard Cite

The technology used in surgery for spinal deformity has progressed rapidly in recent years. Commonly used fixation techniques may include monofilament wires, sublaminar wires and cables, and pedicle screws. Unfortunately, neurological complications can occur with all of these, compromising the patients' health and quality of life. Recently, an alternative fixation technique using a metal clamp and polyester belt was developed to replace hooks and sublaminar wiring in scoliosis surgery. The goal of this study was to compare the pull-out strength of this new construct with sublaminar wiring, laminar hooks and pedicle screws. Forty thoracic vertebrae from five fresh frozen human thoracic spines (T5-12) were divided into five groups (8 per group), such that BMD values, pedicle diameter, and vertebral levels were equally distributed. They were then potted in polymethylmethacrylate and anchored with metal screws and polyethylene bands. One of five fixation methods was applied to the right side of the vertebra in each group: Pedicle screw, sublaminar belt with clamp, figure-8 belt with clamp, sublaminar wire, or laminar hook. Pull-out strength was then assessed using a custom jig in a servohydraulic tester. The mean failure load of the pedicle screw group was significantly larger than that of the figure-8 clamp (P = 0.001), sublaminar belt (0.0172), and sublaminar wire groups (P = 0.04) with no significant difference in pull-out strength between the latter three constructs. The most common mode of failure was the fracture of the pedicle. BMD was significantly correlated with failure load only in the figure-8 clamp and pedicle screw constructs. Only the pedicle screw had a statistically significant higher failure load than the sublaminar clamp. The sublaminar method of applying the belt and clamp device was superior to the figure-8 method. The sublaminar belt and clamp construct compared favorably to the traditional methods of sublaminar wires and laminar hooks, and should be considered as an alternative fixation device in the thoracic spine.

show abstract

“…Thus, tension transmission will occur in a more appropriate manner from the screw to the pedicle. 8 Qualitatively speaking, we found that in addition to the region near medullar canal, at the medial surface of screw's end as compared to the lateral surface, a higher concentration of tensions was seen. This is probably due to the fact that when we apply pullout strength to the screw, the photoelastic model tends to spin over its own axis, counter-clockwise, because the screw is not centered on the model.…”

Section: Referencesmentioning

confidence: 59%

“…the ones identified by Gayet et al 8 who conducted a study using a finite elements method in vertebral models, simulating pullout strength. The authors carried out mechanical pullout assays in order to validate the method employed on the finite element; in these assays, they found that pedicle fractures occurred on sites showing the highest concentration of tension.…”

Section: Referencesmentioning

confidence: 99%

Análise fotoelástica de um modelo de vértebra humana com parafuso pedicular

et al. 2009

View full text Add to dashboard Cite

INTRODUÇÃO: O sistema de fixação vertebral utilizando o parafuso pedicular é um dos métodos mais eficientes no tratamento de patologias da coluna vertebral. Quando o parafuso estiver submetido á força de arrancamento, este gera tensões ao seu redor, principalmente próximas do canal medular, situação esta que pode ser analisada pela técnica da fotoelasticidade. OBJETIVO: Foram analisadas as tensões internas geradas próximas ao canal medular de modelos fotoelásticos de vértebras utilizando diferentes medidas de parafusos do sistema de fixação vertebral submetidos à força de arrancamento. MÉTODO: Foi utilizado um modelo de vértebra lombar em material fotoelástico utilizando três medidas de parafusos pediculares (5, 6 e 7mm) do tipo USS1. As tensões internas ao redor do parafuso foram avaliadas em 12 pontos pré-determinados utilizando um polariscópio de transmissão plana. RESULTADOS: As regiões de maiores concentrações de tensões foram observadas entre o canal medular e as curvas do processo transverso. Nas comparações das médias das tensões cisalhantes máximas entre os parafusos 5 e 7, e 6 e 7 foram observadas diferenças estatísticas significativas e entre 5 e 6 não. CONCLUSÃO: Foi observada que as tensões internas são mais elevadas em áreas irregulares próxima ao canal medular, mostrando ser uma região crítica.

show abstract

Biomechanical Study and Digital Modeling of Traction Resistance in Posterior Thoracic Implants

Cited by 26 publications

References 26 publications

Biomechanical Study of the Pullout Resistance in Screws of a Vertebral Fixation System

Biomechanical Study of the Pullout Resistance in Screws of a Vertebral Fixation System

Biomechanical evaluation of a new fixation device for the thoracic spine

Análise fotoelástica de um modelo de vértebra humana com parafuso pedicular

Contact Info

Product

Resources

About