| Title |
Pedicle screw anchorage of carbon fiber-reinforced PEEK screws under cyclic loading
|
|---|---|
| Published in |
European Spine Journal, March 2018
|
| DOI | 10.1007/s00586-018-5538-8 |
| Pubmed ID | |
| Authors |
Richard A. Lindtner, Rene Schmid, Thomas Nydegger, Marko Konschake, Werner Schmoelz |
| Abstract |
Pedicle screw loosening is a common and significant complication after posterior spinal instrumentation, particularly in osteoporosis. Radiolucent carbon fiber-reinforced polyetheretherketone (CF/PEEK) pedicle screws have been developed recently to overcome drawbacks of conventional metallic screws, such as metal-induced imaging artifacts and interference with postoperative radiotherapy. Beyond radiolucency, CF/PEEK may also be advantageous over standard titanium in terms of pedicle screw loosening due to its unique material properties. However, screw anchorage and loosening of CF/PEEK pedicle screws have not been evaluated yet. The aim of this biomechanical study therefore was to evaluate whether the use of this alternative nonmetallic pedicle screw material affects screw loosening. The hypotheses tested were that (1) nonmetallic CF/PEEK pedicle screws resist an equal or higher number of load cycles until loosening than standard titanium screws and that (2) PMMA cement augmentation further increases the number of load cycles until loosening of CF/PEEK screws. In the first part of the study, left and right pedicles of ten cadaveric lumbar vertebrae (BMD 70.8 mg/cm3 ± 14.5) were randomly instrumented with either CF/PEEK or standard titanium pedicle screws. In the second part, left and right pedicles of ten vertebrae (BMD 56.3 mg/cm3 ± 15.8) were randomly instrumented with either PMMA-augmented or nonaugmented CF/PEEK pedicle screws. Each pedicle screw was subjected to cyclic cranio-caudal loading (initial load ranging from - 50 N to + 50 N) with stepwise increasing compressive loads (5 N every 100 cycles) until loosening or a maximum of 10,000 cycles. Angular screw motion ("screw toggling") within the vertebra was measured with a 3D motion analysis system every 100 cycles and by stress fluoroscopy every 500 cycles. The nonmetallic CF/PEEK pedicle screws resisted a similar number of load cycles until loosening as the contralateral standard titanium screws (3701 ± 1228 vs. 3751 ± 1614 load cycles, p = 0.89). PMMA cement augmentation of CF/PEEK pedicle screws furthermore significantly increased the mean number of load cycles until loosening by 1.63-fold (5100 ± 1933 in augmented vs. 3130 ± 2132 in nonaugmented CF/PEEK screws, p = 0.015). In addition, angular screw motion assessed by stress fluoroscopy was significantly smaller in augmented than in nonaugmented CF/PEEK screws before as well as after failure. Using nonmetallic CF/PEEK instead of standard titanium as pedicle screw material did not affect screw loosening in the chosen test setup, whereas cement augmentation enhanced screw anchorage of CF/PEEK screws. While comparable to titanium screws in terms of screw loosening, radiolucent CF/PEEK pedicle screws offer the significant advantage of not interfering with postoperative imaging and radiotherapy. These slides can be retrieved under Electronic Supplementary Material. |
X Demographics
The data shown below were collected from the profile of 1 X user who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| France | 1 | 100% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 1 | 100% |
Mendeley readers
The data shown below were compiled from readership statistics for 80 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 80 | 100% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 14 | 18% |
| Student > Master | 11 | 14% |
| Student > Doctoral Student | 8 | 10% |
| Student > Bachelor | 8 | 10% |
| Student > Ph. D. Student | 6 | 8% |
| Other | 13 | 16% |
| Unknown | 20 | 25% |
| Readers by discipline | Count | As % |
|---|---|---|
| Medicine and Dentistry | 27 | 34% |
| Engineering | 13 | 16% |
| Neuroscience | 3 | 4% |
| Biochemistry, Genetics and Molecular Biology | 2 | 3% |
| Nursing and Health Professions | 2 | 3% |
| Other | 5 | 6% |
| Unknown | 28 | 35% |
Attention Score in Context
This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 01 March 2018.
All research outputs
#18,589,103
of 23,025,074 outputs
Outputs from European Spine Journal
#2,504
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#257,541
of 331,156 outputs
Outputs of similar age from European Spine Journal
#36
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