TY - JOUR AU - Bereczki, Ferenc AU - Turbucz, Máté AU - Kiss, Rita AU - Éltes, Péter Endre AU - Lazáry, Áron TI - Stability Evaluation of Different Oblique Lumbar Interbody Fusion Constructs in Normal and Osteoporotic Condition – A Finite Element Based Study JF - FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY J2 - FRONT BIOENG BIOTECHNOL VL - 9 PY - 2021 PG - 12 SN - 2296-4185 DO - 10.3389/fbioe.2021.749914 UR - https://m2.mtmt.hu/api/publication/32487457 ID - 32487457 LA - English DB - MTMT ER - TY - JOUR AU - Éltes, Péter Endre AU - Bartos, Márton AU - Hajnal, Benjámin AU - Pokorni, Ágoston Jakab AU - Kiss, László AU - Lacroix, D. AU - Varga, P.P. AU - Lazáry, Áron TI - Development of a Computer-Aided Design and Finite Element Analysis Combined Method for Affordable Spine Surgical Navigation With 3D-Printed Customized Template JF - FRONTIERS IN SURGERY J2 - FRONT SURG VL - 7 PY - 2021 PG - 10 SN - 2296-875X DO - 10.3389/fsurg.2020.583386 UR - https://m2.mtmt.hu/api/publication/31900458 ID - 31900458 AB - Introduction: Revision surgery of a previous lumbosacral non-union is highly challenging, especially in case of complications, such as a broken screw at the first sacral level (S1). Here, we propose the implementation of a new method based on the CT scan of a clinical case using 3D reconstruction, combined with finite element analysis (FEA), computer-assisted design (CAD), and 3D-printing technology to provide accurate surgical navigation to aid the surgeon in performing the optimal surgical technique by inserting a pedicle screw at the S1 level. Materials and Methods: A step-by-step approach was developed and performed as follows: (1) Quantitative CT based patient-specific FE model of the sacrum was created. (2) The CAD model of the pedicle screw was inserted into the sacrum model in a bicortical convergent and a monocortical divergent position, by overcoming the geometrical difficulty caused by the broken screw. (3) Static FEAs (Abaqus, Dassault Systemes) were performed using 500 N tensile load applied to the screw head. (4) A template with two screw guiding structures for the sacrum was designed and manufactured using CAD design and 3D-printing technologies, and investment casting. (5) The proposed surgical technique was performed on the patient-specific physical model created with the FDM printing technology. The patient-specific model was CT scanned and a comparison with the virtual plan was performed to evaluate the template accuracy Results: FEA results proved that the modified bicortical convergent insertion is stiffer (6,617.23 N/mm) compared to monocortical divergent placement (2,989.07 N/mm). The final template was created via investment casting from cobalt-chrome. The template design concept was shown to be accurate (grade A, Gertzbein-Robbins scale) based on the comparison of the simulated surgery using the patient-specific physical model and the 3D virtual surgical plan. Conclusion: Compared to the conventional surgical navigation techniques, the presented method allows the consideration of the patient-specific biomechanical parameters; is more affordable, and the intraoperative X-ray exposure can be reduced. This new patient- and condition-specific approach may be widely used in revision spine surgeries or in challenging primary cases after its further clinical validation. © Copyright © 2021 Eltes, Bartos, Hajnal, Pokorni, Kiss, Lacroix, Varga and Lazary. LA - English DB - MTMT ER - TY - JOUR AU - Costa, MC AU - Éltes, Péter Endre AU - Lazáry, Áron AU - Varga, PP AU - Viceconti, Marco AU - Dall’Ara, E TI - Biomechanical assessment of vertebrae with lytic metastases with subject-specific finite element models JF - JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS J2 - J MECH BEHAV BIOMED VL - 98 PY - 2019 SP - 268 EP - 290 PG - 23 SN - 1751-6161 DO - 10.1016/j.jmbbm.2019.06.027 UR - https://m2.mtmt.hu/api/publication/31036369 ID - 31036369 LA - English DB - MTMT ER - TY - JOUR AU - Rijsbergen, Marc van AU - van Rietbergen, Bert AU - Barthelemy, Veronique AU - Éltes, Péter Endre AU - Lazáry, Áron AU - Lacroix, Damien AU - Noailly, Jérôme AU - Ho Ba Tho, Marie-Christine AU - Wilson, Wouter AU - Ito, Keita TI - Comparison of patient-specific computational models vs. clinical follow-up, for adjacent segment disc degeneration and bone remodelling after spinal fusion JF - PLOS ONE J2 - PLOS ONE VL - 13 PY - 2018 IS - 8 PG - 24 SN - 1932-6203 DO - 10.1371/journal.pone.0200899 UR - https://m2.mtmt.hu/api/publication/31138120 ID - 31138120 AB - Spinal fusion is a standard surgical treatment for patients suffering from low back pain attributed to disc degeneration. However, results are somewhat variable and unpredictable. With fusion the kinematic behaviour of the spine is altered. Fusion and/or stabilizing implants carrying considerable load and prevent rotation of the fused segments. Associated with these changes, a risk for accelerated disc degeneration at the adjacent levels to fusion has been demonstrated. However, there is yet no method to predict the effect of fusion surgery on the adjacent tissue levels, i.e. bone and disc. The aim of this study was to develop a coupled and patient-specific mechanoregulated model to predict disc generation and changes in bone density after spinal fusion and to validate the results relative to patient follow-up data. To do so, a multiscale disc mechanoregulation adaptation framework was developed and coupled with a previously developed bone remodelling algorithm. This made it possible to determine extra cellular matrix changes in the intervertebral disc and bone density changes simultaneously based on changes in loading due to fusion surgery. It was shown that for 10 cases the predicted change in bone density and degeneration grade conforms reasonable well to clinical follow-up data. This approach helps us to understand the effect of surgical intervention on the adjacent tissue remodelling. Thereby, providing the first insight for a spine surgeon as to which patient could potentially be treated successfully by spinal fusion and in which patient has a high risk for adjacent tissue changes. LA - English DB - MTMT ER -