Universität zu Köln

Grevenstein, David, Scheyerer, Max J., Meyer, Carolin, Borggrefe, Jan ORCID: 0000-0003-2908-7560, Hackl, Michael, Oikonomidis, Stavros, Eysel, Peer, Prescher, Andreas and Wegmann, Kilian (2020). Impact of lumbar pedicle screw positioning on screw stability - A biomechanical investigation. Clin. Biomech., 74. S. 66 - 73. OXFORD: ELSEVIER SCI LTD. ISSN 1879-1271

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Abstract

Background: Screw loosening is a major complication following spondylodesis. While several modifications increase screw stability, some, such as screw augmentation, are associated with potential complications; new techniques are needed to minimize the risk of screw loosening without increasing complication rates. Methods: 13 fresh-frozen human lumbar vertebral bodies (L1 to L5) were dissected. In group 1 (n = 7), pedicle screws were implanted conventionally, while in group 2 (n = 6), the screws were positioned divergent in the sagittal pathway. Screw stability was tested under cyclic axial load; one testing-cycle included 1000 repetitions. The first cycle started with a load of 100 N while the load was increased by + 20 N in each following cycle until failure. Failure was defined by either a > 5 mm movement of the screw heads or triggering of the switch-off threshold. Findings: Average number of cycles until failure was increased in group 2 compared with group 1 (12,046 vs 9761 cycles), as was the average load to failure (Fmax 313 N vs 260 N). Overall, in group 2, the number of cycles until screw loosening or failure increased by 23% (p = 0.28), while the required force increased by 20% (p = 0.3). Statistically significant correlation between BMD and increased number of cycles completed as well as with increased load (p < 0.01) could be observed. Interpretation: The results demonstrate, that divergent screw-drift of pairs of screws in the sagittal plane tends to increase stability, especially in vertebral bodies with lower bone density. Moreover, we could demonstrate a correlation between BMD and stability of screw-fixation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Grevenstein, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Scheyerer, Max J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Meyer, Carolin UNSPECIFIED UNSPECIFIED UNSPECIFIED Borggrefe, Jan UNSPECIFIED orcid.org/0000-0003-2908-7560 UNSPECIFIED Hackl, Michael UNSPECIFIED UNSPECIFIED UNSPECIFIED Oikonomidis, Stavros UNSPECIFIED UNSPECIFIED UNSPECIFIED Eysel, Peer UNSPECIFIED UNSPECIFIED UNSPECIFIED Prescher, Andreas UNSPECIFIED UNSPECIFIED UNSPECIFIED Wegmann, Kilian UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-338344
DOI:	10.1016/j.clinbiomech.2020.02.013
Journal or Publication Title:	Clin. Biomech.
Volume:	74
Page Range:	S. 66 - 73
Date:	2020
Publisher:	ELSEVIER SCI LTD
Place of Publication:	OXFORD
ISSN:	1879-1271
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FIXATION; AUGMENTATION Multiple languages Engineering, Biomedical; Orthopedics; Sport Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/33834