Combining 3D tracking and surgical instrumentation to determine the stiffness of spinal motion segments: a validation study

Reutlinger, C; Gédet, P; Büchler, P; Kowal, J; Rudolph, T; Burger, J; Scheffler, K; Hasler, C (2011). Combining 3D tracking and surgical instrumentation to determine the stiffness of spinal motion segments: a validation study. Medical engineering & physics, 33(3), pp. 340-6. Amsterdam: Elsevier 10.1016/j.medengphy.2010.10.021

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The spine is a complex structure that provides motion in three directions: flexion and extension, lateral bending and axial rotation. So far, the investigation of the mechanical and kinematic behavior of the basic unit of the spine, a motion segment, is predominantly a domain of in vitro experiments on spinal loading simulators. Most existing approaches to measure spinal stiffness intraoperatively in an in vivo environment use a distractor. However, these concepts usually assume a planar loading and motion. The objective of our study was to develop and validate an apparatus, that allows to perform intraoperative in vivo measurements to determine both the applied force and the resulting motion in three dimensional space. The proposed setup combines force measurement with an instrumented distractor and motion tracking with an optoelectronic system. As the orientation of the applied force and the three dimensional motion is known, not only force-displacement, but also moment-angle relations could be determined. The validation was performed using three cadaveric lumbar ovine spines. The lateral bending stiffness of two motion segments per specimen was determined with the proposed concept and compared with the stiffness acquired on a spinal loading simulator which was considered to be gold standard. The mean values of the stiffness computed with the proposed concept were within a range of ±15% compared to data obtained with the spinal loading simulator under applied loads of less than 5 Nm.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Surgical Technology & Biomechanics ISTB [discontinued]
04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ophthalmology

UniBE Contributor:

Reutlinger, Christoph; Gédet, Philippe; Büchler, Philippe; Kowal, Horst Jens and Rudolph, Tobias








Factscience Import

Date Deposited:

04 Oct 2013 14:12

Last Modified:

17 Mar 2015 19:15

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URI: (FactScience: 205501)

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