Pullout strength of pedicle screws augmented with particulate calcium phosphate: An experimental study

Hashemi, Ata; Bednar, Drew A.; Ziada, Samir

doi:10.1016/j.spinee.2008.07.001

Cited by 74 publications

(62 citation statements)

References 28 publications

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“…A similar biomechanical effect as observed in the current study was also described by Hashemi et al [8] who found a significantly smaller decrease in pullout resistance after the augmentation of failed pedicle screws with granular calcium-phosphate particles in thoracolumbar vertebrae.…”

Section: Discussionsupporting

confidence: 92%

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

et al. 2012

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Study purpose With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs. Materials and methods Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%). Results The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p \ 0.001/ p = 0.001), the loss of POR (in %) in Group-1 was significantly higher compared with the loss in Group-2 (p = 0.04). Conclusions Using a larger-diameter screw combined with the application of a pedicle bone-plastic, the POR can be significantly increased compared with the use of only an increased screw diameter.

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Section: Discussionsupporting

confidence: 92%

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

et al. 2012

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“…Therefore, it is not reasonable to conclude that the CPN cannot provide sufficient antitorsion capacity at this stage. Also, the current literature appears to focus more on antipullout ability than antitorsion ability of screws, [5][6][7][8][9][10] and thus the need for high antitorsion capacity is still unclear. This question needs more systematic investigation in the future.…”

Section: Discussionmentioning

confidence: 99%

“…[4][5][6][7][8][9][10] Among these bone cements, PMMA is the only clinically approved cement for the augmentation of pedicle-screw fixation. In the routine surgery of augmentation using bone cement, a pilot hole is drilled first and filled with PMMA prior to inserting the screw.…”

mentioning

confidence: 99%

A novel injectable calcium phosphate-based nanocomposite for the augmentation of cannulated pedicle-screw fixation

Sun¹,

Liu²,

Liu³

et al. 2017

IJN

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Polymethyl methacrylate (PMMA)-augmented cannulated pedicle-screw fixation has been routinely performed for the surgical treatment of lumbar degenerative diseases. Despite its satisfactory clinical outcomes and prevalence, problems and complications associated with high-strength, stiff, and nondegradable PMMA have largely hindered the long-term efficacy and safety of pedicle-screw fixation in osteoporotic patients. To meet the unmet need for better bone cement for cannulated pedicle-screw fixation, a new injectable and biodegradable nanocomposite that was the first of its kind was designed and developed in the present study. The calcium phosphate-based nanocomposite (CPN) exhibited better anti-pullout ability and similar fluidity and dispersing ability compared to clinically used PMMA, and outperformed conventional calcium phosphate cement (CPC) in all types of mechanical properties, injectability, and biodegradability. In term of axial pullout strength, the CPN-augmented cannulated screw reached the highest force of ~120 N, which was higher than that of PMMA (~100 N) and CPC (~95 N). The compressive strength of the CPN (50 MPa) was three times that of CPC, and the injectability of the CPN reached 95%. In vivo tests on rat femur revealed explicit biodegradation of the CPN and subsequent bone ingrowth after 8 weeks. The promising results for the CPN clearly suggest its potential for replacing PMMA in the application of cannulated pedicle-screw fixation and its worth of further study and development for clinical uses.

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“…Based on this, we can conclude that our design has obtained 3381 N with the foam modeling healthy bone (grade 40 PU foam), which is approximately three times higher than the strength obtained by Rohmiller with calcium sulphate injected screws. Moreover, Hasemi et al [25] conducted a multi-comparison in their synthetic foam. They studied the pullout strength of several cannulated screw designs on foam.…”

Section: Discussionmentioning

confidence: 99%

Possible Usage of Cannulated Pedicle Screws without Cement Augmentation

Demir

2014

Applied Bionics and Biomechanics

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Abstract. BACKGROUND:The use of pedicle screws is becoming increasingly popular for spinal surgery practice as the technology advances. Screw pullout due to bone quality and loading conditions is one of the most common problems observed after pedicle screw fixation. Several solutions were studied to prevent screw pullout. These can be investigated under three main categories: screw design, expandable screws and cement augmentation. OBJECTIVE: This study aimed to investigate the pullout performance of cannulated screws without cement augmentation on synthetic foams. METHODS: Artificial fusion process for PU is described and validated in our previous studies. For this study six newly designed cannulated pedicle screws were artificially fused to PU foam and pullout test were conducted according to ASTM F543 standard testing protocols. RESULTS: According to the results of post-fusion pullout tests, worst performed cannulated screw design was S3H on healthy bone simulating PU foam. However, pullout strength of unilaterally three holes including (S3H) design was purchased with two times higher loads when compared to control group. Solid cored screws were purchased with 671 N where this value was 1450 N for S3H design. CONCLUSIONS: This study provided that using cannulated pedicle screws without cement augmentation for the cases with healthy bone can be a reliable alternative to classical screws. To the knowledge of the authors this is the first post-fusion study investigating cannulated pedicle screws without cement augmentation.

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Pullout strength of pedicle screws augmented with particulate calcium phosphate: An experimental study

Cited by 74 publications

References 28 publications

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

A novel injectable calcium phosphate-based nanocomposite for the augmentation of cannulated pedicle-screw fixation

Possible Usage of Cannulated Pedicle Screws without Cement Augmentation

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