Biomechanical Evaluation of a Novel Fenestrated Pedicle Screw Augmented With Bone Cement in Osteoporotic Spines

Pare, Philippe; Chappuis, James L.; Rampersaud, Raja; Agarwala, Amit; Perra, Joseph H.; Erkan, Serkan; Wu, Chunhui

doi:10.1097/brs.0b013e318205e3af

Cited by 116 publications

(67 citation statements)

References 22 publications

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“…1,7,14,17,21,24 The main difference among these FPSs is the number of side perforations. Regardless of the different number of perforations, the pullout strength of PMMA-augmented FPSs is greater than that of nonaugmented conventional screws 3,5,9,10,12,26 or cannulated screws 8,16,18 in the osteoporotic condition. In the present study, compared with the nonaugmented CPS group, FPS-A1.0, 1.5, and 2.0 achieved 137%, 207%, and 265% increased pullout strengths, respectively, and FPS-B1.0, 1.5, and 2.0 achieved 166%, 232%, and 269% increased pullout strengths, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, FPSs with different designs have been studied in vitro [3][4][5][8][9][10]12,16,18,26 and in vivo. 1,7,14,17,21,24 The main difference among these FPSs is the number of side perforations.…”

Section: Discussionmentioning

confidence: 99%

“…20,31 Among these approaches, the FPSs augmented by PMMA has achieved the highest fixation strength and best clinical outcomes 1,26 . However, disadvantages remain, such as bone-cement leakage, 3 exothermic damage, 19,28 and pulmonary embolism.…”

Section: 26mentioning

confidence: 99%

“…Therefore, the weak placement of the screw in osteoporotic vertebrae in the aging population remains a considerable challenge faced by spine surgeons. 6,15,20,23,26,27 Additionally, the risk of fixation failure due to screw loosening increases significantly in patients with osteoporotic bone. …”

mentioning

confidence: 99%

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Augmented PMMA distribution: improvement of mechanical property and reduction of leakage rate of a fenestrated pedicle screw with diameter-tapered perforations

Tan

Peng

et al. 2016

SPI

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OBJECTIVE This study investigated the optimum injection volume of polymethylmethacrylate (PMMA) to augment a novel fenestrated pedicle screw (FPS) with diameter-tapered perforations in the osteoporotic vertebral body, and how the distribution characteristics of PMMA affect the biomechanical performance of this screw. METHODS Two types of FPSs were designed (FPS-A, composed of 6 perforations with an equal diameter of 1.2 mm; and FPS-B, composed of 6 perforations each with a tapered diameter of 1.5 mm, 1.2 mm, and 0.9 mm from tip to head. Each of 28 human cadaveric osteoporotic vertebrae were randomly assigned to 1 of 7 groups: FPS-A1.0: FPS-A+1.0 ml PMMA; FPS-A1.5: FPS-A+1.5 ml PMMA; FPS-A2.0: FPS-A+2.0 ml PMMA; FPS-B1.0: FPS-B+1.0 ml PMMA; FPS-B1.5: FPS-B+1.5 ml PMMA; FPS-B2.0: FPS-B+2.0 ml PMMA; and conventional pedicle screws (CPSs) without PMMA. After the augmentation, 3D CT was performed to assess the cement distribution characteristics and the cement leakage rate. Axial pullout tests were performed to compare the maximum pullout force thereafter. RESULTS The CT construction images showed that PMMA bone cement formed a conical mass around FPS-A and a cylindrical mass around FPS-B. When the injection volume was increased from 1.0 ml to 2.0 ml, the distribution region of the PMMA cement was enlarged, the PMMA was distributed more posteriorly, and the risk of leakage was increased. When the injection volume reached 2.0 ml, the risk of cement leakage was lower for screws having diameter-tapered perforations. The pullout strengths of the augmented FPS-A groups and FPS-B groups were higher than that of the CPS group (p < 0.0001). All FPS-B groups had a higher pullout strength than the FPS-A groups. CONCLUSIONS The diameter of the perforations affects the distribution of PMMA cement. The diameter-tapered design enabled PMMA to form larger bone-PMMA interfaces and achieve a relatively higher pullout strength, although statistical significance was not reached. Study results indicated 1.5-ml of PMMA was a conservative volume for PMMA augmentation; more cement injection would significantly increase the risk of cement leakage.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: 26mentioning

confidence: 99%

mentioning

confidence: 99%

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Augmented PMMA distribution: improvement of mechanical property and reduction of leakage rate of a fenestrated pedicle screw with diameter-tapered perforations

Tan

Peng

et al. 2016

SPI

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“…They also found that the failure rate of CPS can be reduced by reducing the number of the radial hole. Although the effect of parameters of the radial holes (diameter and position of radial holes) on failure rate of CPS have been proof experimentally and numerically by several researchers [4][5][6][7][8][9][10], the optimum position and diameter of radial holes still becoming one of the gap in this research field. Thus, the aim of this paper is to propose the design optimization of cannulated pedicle screw which focuses more on optimization of diameter and position of radial holes.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Position and Different Size of Radial Hole on Performance of Cannulated Pedicle Screw

et al. 2017

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Abstract. Cannulated Pedicle Screw (CPS) is the instrumentation that has been introduced in Biomedical field in order to stabilize the spine structure and also to enhance the pullout strength in osteoporotic patient. The cement is injected through the CPS which is flow from the screw head to the radial hole and then distributed around the CPS to give higher performance of pullout strength. However, the fracture still reported to happened around the radial hole. This paper is aim to focus on the effect of the position and different diameter of radial hole on the CPS. Three designs were constructed using SolidWork software where two of it are the current models whereas the third was the proposed design which the radial holes were position differently (skewed to each other) and its size is smaller than the current model, 1.0 mm and 1.5mm respectively. The software used for Finite Element Analysis (FEA) is Ansys workbench 16.0. The Finite Element Models were verified with FEA result of the previous research. The FEA results of torsional stress for current and proposed design were then compared to obtain the maximum torque that both designs are able to resist before fracture. It can be concluded that the performance of CPS can be improved by the proposed design which is 2 radial hole skewed to each other and smaller radial hole diameter (1.0mm) than the current cannulated pedicle screw (1.5mm).

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Cement augmentation of hip implants in osteoporotic bone: How much cement is needed and where should it go?

et al. 2013

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Several studies proved the beneficial effect of cement augmentation of proximal femoral nail antirotation (PFNA) blades on implant purchase in osteoporotic bone. We investigated the effect of different localizations and amounts of bone cement. Polyurethane foam specimens were instrumented with a PFNA blade and subsequently augmented with PMMA bone cement. Eight study groups were formed based on localization and amount of cement volume related to the blade. All specimens underwent cyclic loading with physiological orientation of the force vector until construct failure. Foam groups were compared between each other and to a cadaveric control group. The experiments revealed a significant dependency of implant purchase on localization and amount of cement. Biomechanically favorable cement positions were found at the implant tip and at the cranial side. However, none of the tested augmentation patterns performed significantly inferior to the cadaveric benchmark. These findings will allow surgeons to further reduce the amount of injected PMMA, decreasing the risk of cement leakage or cartilage damage. With the use of fixation devices like helical blades for treating proximal femoral fractures, the incidence of cut-out of cephalic implants has decreased.1-5 Nevertheless failures occur. Besides surgeon-related factors such as quality of the reduction and implant positioning, bone quality plays an important role in the occurrence of mechanical complications. 6,7 Due to the aging population and relatively poor compliance to drugs that prevent osteoporotic fractures, the incidence of osteoporosis related fractures will increase.

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Biomechanical Evaluation of a Novel Fenestrated Pedicle Screw Augmented With Bone Cement in Osteoporotic Spines

Cited by 116 publications

References 22 publications

Augmented PMMA distribution: improvement of mechanical property and reduction of leakage rate of a fenestrated pedicle screw with diameter-tapered perforations

Augmented PMMA distribution: improvement of mechanical property and reduction of leakage rate of a fenestrated pedicle screw with diameter-tapered perforations

The Effect of Position and Different Size of Radial Hole on Performance of Cannulated Pedicle Screw

Cement augmentation of hip implants in osteoporotic bone: How much cement is needed and where should it go?

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