Surgical instrumentation for the in vivo determination of lumbar spinal segment stiffness and viscoelasticity

Ambrosetti-Giudici, S; Pfenniger, Aloïs; Krenn, MH; Piotrowski, WP; Ferguson, SJ; Burger, J (2009). Surgical instrumentation for the in vivo determination of lumbar spinal segment stiffness and viscoelasticity. Medical engineering & physics, 31(9), 1063 - 1068. Amsterdam: Elsevier 10.1016/j.medengphy.2009.07.002

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The definition of spinal instability is still controversial. For this reason, it is essential to better understand the difference in biomechanical behaviour between healthy and degenerated human spinal segments in vivo. A novel computer-assisted instrument was developed with the objective to characterize the biomechanical parameters of the spinal segment. Investigation of the viscoelastic properties as well as the dynamic spinal stiffness was performed during a minimally invasive procedure (microdiscectomy) on five patients. Measurements were performed intraoperatively and the protocol consisted of a dynamic part, where spinal stiffness was computed, and a static part, where force relaxation of the segment under constant elongation was studied. The repeatability of the measurement procedure was demonstrated with five replicated tests. The spinal segment tissues were found to have viscoelastic properties. Preliminary tests confirmed a decrease in stiffness after decompression surgery. Patients with non-relaxed muscles showed higher stiffness and relaxation rate compared to patients with relaxed muscles, which can be explained by the contraction and relaxation reflex of muscles under fast and then static elongation. The results show the usefulness of the biomechanical characterization of the human lumbar spinal segment to improve the understanding of the contribution of individual anatomical structures to spinal stability.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Cardiovascular Engineering (CVE) > ARTORG Center - Cardiovascular Engineering (Blood Vessel)
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Surgical Technology & Biomechanics ISTB [discontinued]

UniBE Contributor:

Pfenniger, Aloïs and Ferguson, Stephen John








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Date Deposited:

04 Oct 2013 15:09

Last Modified:

11 Jul 2014 09:17

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URI: (FactScience: 194727)

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