Biomechanical evaluation of different semi-rigid junctional fixation techniques using finite element analysis

Julia L van Agtmaal; Remco J P Doodkorte; Alex K Roth; Keita Ito; Jacobus J C Arts; Paul C Willems; Bert van Rietbergen

doi:10.1016/j.clinbiomech.2023.106071

Biomechanical evaluation of different semi-rigid junctional fixation techniques using finite element analysis

Clin Biomech (Bristol, Avon). 2023 Aug:108:106071. doi: 10.1016/j.clinbiomech.2023.106071. Epub 2023 Aug 12.

Authors

Julia L van Agtmaal¹, Remco J P Doodkorte², Alex K Roth², Keita Ito³, Jacobus J C Arts¹, Paul C Willems², Bert van Rietbergen⁴

Affiliations

¹ Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands; Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands.
² Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands.
³ Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands.
⁴ Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands; Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands. Electronic address: b.v.rietbergen@tue.nl.

PMID: 37597385
DOI: 10.1016/j.clinbiomech.2023.106071

Abstract

Background: Proximal junctional failure is a common complication attributed to the rigidity of long pedicle screw fixation constructs used for surgical correction of adult spinal deformity. Semi-rigid junctional fixation achieves a gradual transition in range of motion at the ends of spinal instrumentation, which could lead to reduced junctional stresses, and ultimately reduce the incidence of proximal junctional failure. This study investigates the biomechanical effect of different semi-rigid junctional fixation techniques in a T8-L3 finite element spine segment model.

Methods: First, degeneration of the intervertebral disc was successfully implemented by altering the height. Second, transverse process hooks, one- and two-level clamped tapes, and one- and two-level knotted tapes instrumented proximally to three-level pedicle screw fixation were validated against ex vivo range of motion data of a previous study. Finally, the posterior ligament complex forces and nucleus pulposus stresses were quantified.

Findings: Simulated range of motions demonstrated the fidelity of the general model and modelling of semi-rigid junctional fixation techniques. All semi-rigid junctional fixation techniques reduced the posterior ligament complex forces at the junctional zone compared to pedicle screw fixation. Transverse process hooks and knotted tapes reduced nucleus pulposus stresses, whereas clamped tapes increased nucleus pulposus stresses at the junctional zone.

Interpretation: The relationship between the range of motion transition and the reductions in posterior ligament complex and nucleus pulposus stresses was complex and dependent on the fixation techniques. Clinical trials are required to compare the effectiveness of semi-rigid junctional fixation techniques in terms of reducing proximal junctional failure incidence rates.

Keywords: Adult spinal deformity; Finite element modelling; Proximal junctional kyphosis; Spine biomechanics.

MeSH terms

Adult
Finite Element Analysis
Humans
Motion
Pedicle Screws*
Plastic Surgery Procedures*
Range of Motion, Articular