Universität zu Köln

Beckman, Agnes, Herren, Christian, Nicolini, Luis Fernando, Grevenstein, David, Oikonomidis, Stavros ORCID: 0000-0002-7637-8611, Kobbe, Philipp, Hildebrand, Frank, Stoffel, Marcus, Markert, Bernd ORCID: 0000-0001-7893-6229 and Siewe, Jan (2019). Biomechanical testing of a polycarbonate-urethane-based dynamic instrumentation system under physiological conditions. Clin. Biomech., 61. S. 112 - 120. OXFORD: ELSEVIER SCI LTD. ISSN 1879-1271

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Abstract

Background: Posterior dynamic stabilization systems are developed to maintain the healthy biomechanics of the spine while providing stabilization. Numerous dynamic systems incorporate polycarbonate urethane with temperature- and moisture-dependent material properties. In the underlying study, a novel test rig is used to evaluate the biomechanical performance of a system containing polycarbonate urethane. Methods: The test rig is composed of two hydraulic actuators. An environmental chamber, filled with water vapor at body temperature, is included in the set up. The translational and rotational degrees of freedom of vertebrae and pedicle screws are measured using a magnetic tracking system. The Transition device is tested in five lumbar spines (L2-L5) of human cadavers. Pure moment tests are performed for flexion-extension, lateral bending, and axial rotation. Three test conditions are compared: 1. native specimens, 2. dynamic instrumentation at L4-L5, 3. dynamic instrumentation with decompression at L4-L5. Findings: The ranges of motion, the centers of rotation, and the pedicle screw loosening are calculated and evaluated. During daily motions such as walking, the loads on the lumbar spine differ from the standardized test protocols. To allow a reproducible data evaluation for smaller deformations, all moment-rotation curves are parameterized using sigmoid functions. Interpretation: In flexion-extension, the Transition device provides the highest stiffening of the segment and the largest shift of the center of rotation. No shift in the center of rotation, and the smallest supporting effect on the segment is observed for axial rotation. In lateral bending, a mediate reduction of the range of motion is observed.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Beckman, Agnes UNSPECIFIED UNSPECIFIED UNSPECIFIED Herren, Christian UNSPECIFIED UNSPECIFIED UNSPECIFIED Nicolini, Luis Fernando UNSPECIFIED UNSPECIFIED UNSPECIFIED Grevenstein, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Oikonomidis, Stavros UNSPECIFIED orcid.org/0000-0002-7637-8611 UNSPECIFIED Kobbe, Philipp UNSPECIFIED UNSPECIFIED UNSPECIFIED Hildebrand, Frank UNSPECIFIED UNSPECIFIED UNSPECIFIED Stoffel, Marcus UNSPECIFIED UNSPECIFIED UNSPECIFIED Markert, Bernd UNSPECIFIED orcid.org/0000-0001-7893-6229 UNSPECIFIED Siewe, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-139483
DOI:	10.1016/j.clinbiomech.2018.12.003
Journal or Publication Title:	Clin. Biomech.
Volume:	61
Page Range:	S. 112 - 120
Date:	2019
Publisher:	ELSEVIER SCI LTD
Place of Publication:	OXFORD
ISSN:	1879-1271
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language IN-VITRO; STABILIZATION SYSTEM; DISC DEGENERATION; SPINAL STENOSIS; PEDICLE SCREWS; LUMBAR SPINE; SURGERY; MOTION; DECOMPRESSION Multiple languages Engineering, Biomedical; Orthopedics; Sport Sciences Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/13948