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PLoS One. 2019 Mar 6;14(3):e0212681. doi: 10.1371/journal.pone.0212681. eCollection 2019.

In-silico pre-clinical trials are made possible by a new simple and comprehensive lumbar belt mechanical model based on the Law of Laplace including support deformation and adhesion effects.

Author information

Mines Saint-Etienne, Univ Lyon, Univ Jean Monnet, INSERM, U 1059 Sainbiose, Centre CIS, Saint-Etienne, France.
Thuasne, Saint-Etienne, France.
Univ Lyon, UJM Saint-Etienne, LIBM, CHU Saint-Etienne, Physical medicine and rehabilitation, Saint-Etienne, France.


Lower back pain is a major public health problem. Despite claims that lumbar belts change spinal posture due to applied pressure on the trunk, no mechanical model has yet been published to prove this treatment. This paper describes a first model for belt design, based on the one hand on the mechanical properties of the fabrics and the belt geometry, and on the other hand on the trunk geometrical and mechanical description. The model provides the estimation of the pressure applied to the trunk, and a unique indicator of the belt mechanical efficiency is proposed: pressure is integrated into a bending moment characterizing the belt delordosing action on the spine. A first in-silico clinical study of belt efficiency for 15 patients with 2 different belts was conducted. Results are very dependent on the body shape: in the case of high BMI patients, the belt effect is significantly decreased, and can be even inverted, increasing the lordosis. The belt stiffness proportionally increases the pressure applied to the trunk, but the influence of the design itself on the bending moment is clearly outlined. Moreover, the belt/trunk interaction, modeled as sticking contact and the specific way patients lock their belts, dramatically modifies the belt action. Finally, even if further developments and tests are still necessary, the model presented in this paper seems suitable for in-silico pre-clinical trials on real body shapes at a design stage.

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Conflict of interest statement

Mines Saint-Etienne (Jérôme Molimard, Woo Suck Han) and CHU Saint-Etienne (Paul Calmels) received funds from Thuasne in the context of this work. Rebecca Bonnaire and Reynald Convert are directly hired by Thuasne. The authors declare that they do not have any other financial or non financial competing interests. There are no patents, products in development or marketed products associated with this research to declare. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

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