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Biomechanical comparison of effects of the Dynesys and Coflex dynamic stabilization systems on range of motion and loading characteristics in the lumbar spine: a finite element study
Author(s) -
Kulduk Ahmet,
Altun Necdet S.,
Senkoylu Alpaslan
Publication year - 2015
Publication title -
the international journal of medical robotics and computer assisted surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 53
eISSN - 1478-596X
pISSN - 1478-5951
DOI - 10.1002/rcs.1636
Subject(s) - range of motion , finite element method , materials science , lumbar spine , lumbar , biomechanics , bending , mechanics , computer science , biomedical engineering , structural engineering , physics , composite material , engineering , medicine , surgery , anatomy
Background The primary purpose of dynamic stabilization is to preserve the normal range of motion (ROM) by restricting abnormal movement in the spine. Our aim was to analyze the effects of two different dynamic stabilization systems using finite element modeling (FEM). Methods Coflex and Dynesys dynamic devices were modeled and implanted at the L4‐L5 segment using virtual FEM. A 400 N compressive force combined with 6 N flexion, extension, bending and axial rotation forces was applied to the L3‐4 and L4‐5 segments. ROM and disc loading forces were analyzed. Results Both systems reduced ROM and disc loading forces at the implanted lumbar segment, with the exception of the Coflex interspinous device, which increased ROM by 19% and did not change disc‐loading forces in flexion. Conclusions The Coflex device prevented excessive disc loading, but increased ROM abnormally in flexion. Neither device provided satisfactory motion preservation or load sharing in other directions. Copyright © 2015 John Wiley & Sons, Ltd.