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Germaneau A, Vendeuvre T, Delmotte A, D'Houtaud S, Brèque C, Petureau L, Doumalin P, Dupré JC, Brémand F, Maxy P, Richer JP, Rigoard P. Should we recommend occipital plate fixation using bicortical screws or inverted occipital hooks to optimize occipito-cervical junction fusion? A biomechanical study combining an experimental and analytical approach. Clin Biomech (Bristol, Avon) 2020; 80:105173. [PMID: 33010700 DOI: 10.1016/j.clinbiomech.2020.105173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Occipito-cervical fusion can be necessary in case of cranio-cervical junction instability. Proximal stabilisation is usually ensured by bi-cortical occipital screws implanted through one median or two lateral occipital plate(s). Bone thickness variability as well as the proximity of vasculo-nervous elements can induce substantial morbidity. The choice of site and implant type remains difficult for surgeons and is often empirically based. Given this challenge, implants with smaller pitch to increase bone interfacing are being developed, as is a surgical technique consisting in inverted occipital hook clamps, a potential alternative to plate/screws association. We present here a biomechanical comparison of the different occipito-cervical fusion devices. METHODS We have developed a 3D mark tracking technique to measure experimental mechanical data on implants and occipital bone. Biomechanical tests were performed to study the mechanical stiffness of the occipito-cervical instrumentation on human skulls. Four occipital implant systems were analysed: lateral plates+large pitch screws, lateral plates+hooks, lateral plates+small pitch screws and median plate+small pitch screws. Mechanical responses were analysed using 3D displacement field measurements from optical methods and compared with an analytical model. FINDINGS Paradoxical mechanical responses were observed among the four types of fixations. Lateral plates+small pitch screws appear to show the best accordance of displacement field between bone/implant/system interface providing higher stiffness and an average maximum moment around 50 N.m before fracture. INTERPRETATION Stability of occipito-cervical fixation depends not only on the site of screws implantation and occipital bone thickness but is also directly influenced by the type of occipital implant.
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Affiliation(s)
- Arnaud Germaneau
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France.
| | - Tanguy Vendeuvre
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France
| | - Alexandre Delmotte
- Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France; Centre du Rachis de la Sauvergarde, 69009 Lyon, France
| | - Samuel D'Houtaud
- Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France; Service de Neurochirurgie Clinique, La Rochelle, France
| | - Cyril Brèque
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; ABS Lab, Université de Poitiers, France
| | - Louis Petureau
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - Pascal Doumalin
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | | | - Fabrice Brémand
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - Philippe Maxy
- Medtronic, Medtronic International Trading Sarl, Tolochenaz, Switzerland
| | | | - Philippe Rigoard
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Spine & Neuromodulation Functional Unit, Department of Neurosurgery, CHU Poitiers, PRISMATICS Lab, Poitiers, France
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Germaneau A, Vendeuvre T, Saget M, Doumalin P, Dupré JC, Brémand F, Hesser F, Brèque C, Maxy P, Roulaud M, Monlezun O, Rigoard P. Development of an experimental model of burst fracture with damage characterization of the vertebral bodies under dynamic conditions. Clin Biomech (Bristol, Avon) 2017; 49:139-144. [PMID: 28938147 DOI: 10.1016/j.clinbiomech.2017.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Burst fractures represent a significant proportion of fractures of the thoracolumbar junction. The recent advent of minimally invasive techniques has revolutionized the surgical treatment of this type of fracture. However mechanical behaviour and primary stability offered by these solutions have to be proved from experimental validation tests on cadaveric specimens. Therefore, the aim of this study was to develop an original and reproducible model of burst fracture under dynamic impact. METHODS Experimental tests were performed on 24 cadaveric spine segments (T11-L3). A system of dynamic loading was developed using a modified Charpy pendulum. The mechanical response of the segments (strain measurement on vertebrae and discs) was obtained during the impact by using an optical method with a high-speed camera. The production of burst fracture was validated by an analysis of the segments by X-ray tomography. FINDINGS Burst fracture was systematically produced on L1 for each specimen. Strain analysis during impact highlighted the large deformation of L1 due to the fracture and small strains in adjacent vertebrae. The mean reduction of the vertebral body of L1 assessed for all the specimens was around 15%. No damage was observed in adjacent discs or vertebrae. INTERPRETATION With this new, reliable and replicable procedure for production and biomechanical analysis of burst fractures, comparison of different types of stabilization systems can be envisaged. The loading system was designed so as to be able to produce loads leading to other types of fractures and to provide data to validate finite element modelling.
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Affiliation(s)
- A Germaneau
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France.
| | - T Vendeuvre
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Department of Orthopaedic Surgery and Traumatology, CHU, Poitiers, France
| | - M Saget
- Department of Orthopaedic Surgery and Traumatology, CHU, Poitiers, France
| | - P Doumalin
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - J C Dupré
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - F Brémand
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - F Hesser
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France
| | - C Brèque
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; ABS Lab, Université de Poitiers, France
| | - P Maxy
- Medtronic International Trading Sarl, Tolochenaz, Switzerland
| | - M Roulaud
- Department of Neurosurgery, Prismatics Lab, CHU, Poitiers, France
| | - O Monlezun
- Department of Neurosurgery, Prismatics Lab, CHU, Poitiers, France
| | - P Rigoard
- Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, France; Department of Neurosurgery, Prismatics Lab, CHU, Poitiers, France
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Couvertier M, Germaneau A, Saget M, Dupré JC, Doumalin P, Brémand F, Hesser F, Brèque C, Roulaud M, Monlezun O, Vendeuvre T, Rigoard P. Biomechanical analysis of the thoracolumbar spine under physiological loadings: Experimental motion data corridors for validation of finite element models. Proc Inst Mech Eng H 2017; 231:975-981. [PMID: 28707505 DOI: 10.1177/0954411917719740] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Biomechanical studies that involve normal, injured or stabilized human spines are sometimes difficult to perform on large samples due to limited access to cadaveric human spines and biological variability. Finite element models alleviate these limitations due to the possibility of reusing the same model, whereas cadaveric spines can be damaged during testing, or have their mechanicals behaviour modified by fatigue, permanent deformation or structural failure. Finite element models need to be validated with experimental data to make sure that they represent the complex mechanical and physiological behaviour of normal, injured and stabilized spinal segments. The purpose of this study is to characterize the mechanical response of thoracolumbar spine segments with an analytical approach drawn from experimental measurements. A total of 24 normal and fresh cadaveric thoracolumbar spine segments (T11-L3), aged between 53 and 91 years, were tested in pure flexion/extension, lateral bending and axial torsion using a specific experimental setup. Measurements of global and intervertebral angle variations were performed using three-dimensional mark tracking methods. Load/angle curves for each loading were fitted by a logarithmic approach with two coefficients. The coefficients for the functions describing the response of the spinal segments are given and constitute predictive models from experimental data. This work provides data corridors of human thoracolumbar spine motion segments subjected to pure bending in the three physiological planes. These data could be very useful to validate finite element models of the human spine.
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Affiliation(s)
- Marien Couvertier
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Arnaud Germaneau
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Mathieu Saget
- 2 Department of Orthopaedic Surgery and Traumatology, CHU, Poitiers, France
| | - Jean-Christophe Dupré
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Pascal Doumalin
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Fabrice Brémand
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Franck Hesser
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France
| | - Cyril Brèque
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France.,3 ABS Lab, Université de Poitiers, Poitiers, France
| | - Manuel Roulaud
- 4 Department of Neurosurgery, Spine & Neuromodulation Functional Unit, Prismatics Lab, CHU, Poitiers, France
| | - Olivier Monlezun
- 4 Department of Neurosurgery, Spine & Neuromodulation Functional Unit, Prismatics Lab, CHU, Poitiers, France
| | - Tanguy Vendeuvre
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France.,2 Department of Orthopaedic Surgery and Traumatology, CHU, Poitiers, France
| | - Philippe Rigoard
- 1 Institut Pprime UPR 3346, CNRS - Université de Poitiers - ISAE-ENSMA, Futuroscope-Chasseneuil, France.,4 Department of Neurosurgery, Spine & Neuromodulation Functional Unit, Prismatics Lab, CHU, Poitiers, France
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