The effects of tether pretension within vertebral body tethering on the biomechanics of the spine: a Finite Element analysis

Latin American Journal of Solids and Structures, vol. 19

Abstract

This study investigates the biomechanics of the spine after insertion of vertebral body tethering (VBT) with different cord pretensions. For that purpose, a Finite Element model of the average thoracolumbar spine was stepwise calibrated and validated. The VBT instrumentation was inserted in the left side of the L1-L2 segment with different cord pretensions. As a second test, the L1-L2 segment was submitted to an external pure moment of 6 Nm in left and right lateral bending. The range of motion (ROM) for the spine with VBT was determined with respect to its initial post VBT position. Pretension forces of 100 N and 300 N resulted in a change of scoliotic angle of 2.7° and 5.3° to the left side of the spine, respectively. The ROM of the native spine was 4.5° in right lateral bending and reduced to 1.8° and 1.4° for the cases of the spine with a cord pretension of 100 N and 300 N, respectively. In left lateral bending, the absolute ROM of the native spine was 4.6°. For the cases of a cord pretension of 100 N and 300 N, the spine bent 1.9° and 0.8° to the left side from its initial post VBT position, respectively.

Authors 10

1. Luis Fernando Nicolini

   Universidade Federal de Santa Catarina

   Affiliation as printed

   Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil

   Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil

2. Johannes Greven Aachen

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   RWTH Aachen University Hospital, Germany

   RWTH Aachen University Hospital, Germany

3. Philipp Kobbe Aachen

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   RWTH Aachen University Hospital, Germany

   RWTH Aachen University Hospital, Germany

4. Frank Hildebrand Aachen

   RWTH Aachen University · Universitätsklinikum Aachen

   Affiliation as printed

   RWTH Aachen University Hospital, Germany

   RWTH Aachen University Hospital, Germany

5. Marcus Stoffel Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Germany

   RWTH Aachen University, Germany

6. Bernd A. Markert Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Germany

   RWTH Aachen University, Germany

7. Borja Martinez Yllera

   Universidade Federal de Santa Catarina

   Affiliation as printed

   Universidade Federal de Santa Catarina, Brasil

   Universidade Federal de Santa Catarina, Brasil

8. Marcelo Simoni Simões

   Universidade Federal de Santa Catarina

   Affiliation as printed

   Universidade Federal de Santa Catarina, Brasil

   Universidade Federal de Santa Catarina, Brasil

9. Carlos Rodrigo de Mello Roesler

   Universidade Federal de Santa Catarina

   Affiliation as printed

   Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil

   Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil

10. Eduardo Alberto Fancello

    Universidade Federal de Santa Catarina

    Affiliation as printed

    Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil

    Universidade Federal de Santa Catarina, Brasil; Universidade Federal de Santa Catarina, Brasil