open access

Vol 52, No 1 (2018)
Original research articles
Submitted: 2017-08-26
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In vitro simulation of intraoperative vertebroplasty applied for pedicle screw augmentation. A biomechanical evaluation

Krzysztof Zapałowicz, Agnieszka Kierzkowska, Lechosław F. Ciupik
DOI: 10.1016/j.pjnns.2017.12.001
·
Neurol Neurochir Pol 2018;52(1):64-69.

open access

Vol 52, No 1 (2018)
Original research articles
Submitted: 2017-08-26

Abstract

Background and purpose

The purpose of this study was to evaluate the effect of an in vitro simulation of intraoperative vertebroplasty on embedded pedicle screws resistance to pullout. This method involved an application of acrylic cement into the vertebral bodies only after pedicle screws implementation.

Materials and methods

For the purpose of conducting this research, the authors used the spines of fully-grown pigs. The procedure was as follows: firstly, the pedicle screws were bilaterally implemented in 10 vertebrae; secondly, cancellous bone was removed from vertebral bodies selected for screws augmentation and lastly it was replaced by polymethylmethacrylate (PMMA). Six vertebrae with implemented pedicle screws served as a control group. The pullout strength of thirty-two screws (20 augmented and 12 control) was tested. All screws were pulled out at a crosshead speed of 5mm/min.

Results

The PMMA-augmented screws showed a 1.3 times higher average pullout force than the control group: respectively 1539.68N and 1156.59N. In essence, no significant discrepancy was determined between average pullout forces of screws which were pulled as first when compared with consecutive contralateral ones.

Conclusions

An in vitro simulation of intraoperative injection of PMMA in the vertebral body instrumented with screws (intraoperative vertebroplasty) resulted in enhancing its pullout strength by 33%. Pulling of one of the pedicular screws from the augmented vertebral body did not affect the pullout resistance of the contralateral one.

Abstract

Background and purpose

The purpose of this study was to evaluate the effect of an in vitro simulation of intraoperative vertebroplasty on embedded pedicle screws resistance to pullout. This method involved an application of acrylic cement into the vertebral bodies only after pedicle screws implementation.

Materials and methods

For the purpose of conducting this research, the authors used the spines of fully-grown pigs. The procedure was as follows: firstly, the pedicle screws were bilaterally implemented in 10 vertebrae; secondly, cancellous bone was removed from vertebral bodies selected for screws augmentation and lastly it was replaced by polymethylmethacrylate (PMMA). Six vertebrae with implemented pedicle screws served as a control group. The pullout strength of thirty-two screws (20 augmented and 12 control) was tested. All screws were pulled out at a crosshead speed of 5mm/min.

Results

The PMMA-augmented screws showed a 1.3 times higher average pullout force than the control group: respectively 1539.68N and 1156.59N. In essence, no significant discrepancy was determined between average pullout forces of screws which were pulled as first when compared with consecutive contralateral ones.

Conclusions

An in vitro simulation of intraoperative injection of PMMA in the vertebral body instrumented with screws (intraoperative vertebroplasty) resulted in enhancing its pullout strength by 33%. Pulling of one of the pedicular screws from the augmented vertebral body did not affect the pullout resistance of the contralateral one.

Get Citation

Keywords

Vertebroplasty, Transpedicular stabilization, Screw augmentation, Polymethylmethacrylate, Biomechanics

About this article
Title

In vitro simulation of intraoperative vertebroplasty applied for pedicle screw augmentation. A biomechanical evaluation

Journal

Neurologia i Neurochirurgia Polska

Issue

Vol 52, No 1 (2018)

Pages

64-69

DOI

10.1016/j.pjnns.2017.12.001

Bibliographic record

Neurol Neurochir Pol 2018;52(1):64-69.

Keywords

Vertebroplasty
Transpedicular stabilization
Screw augmentation
Polymethylmethacrylate
Biomechanics

Authors

Krzysztof Zapałowicz
Agnieszka Kierzkowska
Lechosław F. Ciupik

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