1
|
Nafo W, Guldeniz O, Jun H, Kim E. Ligamentous tethering and intradiscal pressure affecting the mechanical environment of scoliotic spines. Med Eng Phys 2023; 119:104035. [PMID: 37634912 DOI: 10.1016/j.medengphy.2023.104035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 07/21/2023] [Accepted: 08/06/2023] [Indexed: 08/29/2023]
Abstract
Despite several theories have been proposed to explain the progression of Adolescent Idiopathic Scoliosis (AIS), there is no consensus on the mechanical factors that control the spinal deformities. Prominent biomechanical notions focus on the geometrical asymmetry and differential growth, however, the correlation between these phenomena remains unclear. We postulate that intradiscal pressure and its connection with the supporting ligamentous structures are the reasons behind the asymmetric growth in AIS. To investigate this hypothesis, a numerical 3D patient-specific model of a scoliotic spine is constructed to carry upper body weight. Four analyses are performed: control simulation with no ligaments followed by 3 simulations, in each, a different and stiffer set of ligaments is employed. The analyses showed that intradiscal pressure is relatively high in the spine's higher-deformity region. Moreover, the stiffness effect of the ligamentous tethering correlated directly to intradiscal pressure; the stiffer the ligaments, the higher the intradiscal pressure. Due to geometrical asymmetry, the pressure is eccentric toward the concave region of deformed vertebral units. As a result, the deformed annulus fibrosus generated uplifts in the convex side of deformed vertebral units. The eccentric pressure and the uplift are opposite in location and direction creating an imbalanced mechanical environment for the spine during growth.
Collapse
Affiliation(s)
- Wanis Nafo
- Mechanical System Engineering Department, Jeonbuk Nationa University, Jeonju-si, Jeollabuk-do, South Korea.
| | - Ogulcan Guldeniz
- Orthopaedics and Traumatology Department, University of Hong Kong, Hong Kong SAR, China
| | - Hyungmin Jun
- Mechanical System Engineering Department, Jeonbuk Nationa University, Jeonju-si, Jeollabuk-do, South Korea
| | - Eunho Kim
- Mechanical System Engineering Department, Jeonbuk Nationa University, Jeonju-si, Jeollabuk-do, South Korea
| |
Collapse
|
2
|
Vanaclocha A, Vanaclocha V, Atienza CM, Clavel P, Jordá-Gómez P, Barrios C, Vanaclocha L. Bionate ® nucleus disc replacement: bench testing comparing two different designs. J Orthop Traumatol 2023; 24:13. [PMID: 37041425 PMCID: PMC10090247 DOI: 10.1186/s10195-023-00692-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 03/12/2023] [Indexed: 04/13/2023] Open
Abstract
BACKGROUND Intervertebral disc nucleus degeneration initiates a degenerative cascade and can induce chronic low back pain. Nucleus replacement aims to replace the nucleus while the annulus is still intact. Over time, several designs have been introduced, but the definitive solution continues to be elusive. Therefore, we aimed to create a new nucleus replacement that replicates intact intervertebral disc biomechanics, and thus has the potential for clinical applications. MATERIALS AND METHODS Two implants with an outer ring and one (D2) with an additional midline strut were compared. Static and fatigue tests were performed with an INSTRON 8874 following the American Society for Testing and Materials F2267-04, F2346-05, 2077-03, D2990-01, and WK4863. Implant stiffness was analyzed at 0-300 N, 500-2000 N, and 2000-6000 N and implant compression at 300 N, 1000 N, 2000 N, and 6000 N. Wear tests were performed following ISO 18192-1:2008 and 18192-2:2010. GNU Octave software was used to calculate movement angles and parameters. The statistical analysis package R was used with the Deducer user interface. Statistically significant differences between the two designs were analyzed with ANOVA, followed by a post hoc analysis. RESULTS D1 had better behavior in unconfined compression tests, while D2 showed a "jump." D2 deformed 1 mm more than D1. Sterilized implants were more rigid and deformed less. Both designs showed similar behavior under confined compression and when adding shear. A silicone annulus minimized differences between the designs. Wear under compression fatigue was negligible for D1 but permanent for D2. D1 suffered permanent height deformation but kept its width. D2 suffered less height loss than D1 but underwent a permanent width deformation. Both designs showed excellent responses to compression fatigue with no breaks, cracks, or delamination. At 10 million cycles, D2 showed 3-times higher wear than D1. D1 had better and more homogeneous behavior, and its wear was relatively low. It showed good mechanical endurance under dynamic loading conditions, with excellent response to axial compression fatigue loading without functional failure after long-term testing. CONCLUSION D1 performed better than D2. Further studies in cadaveric specimens, and eventually in a clinical setting, are recommended. Level of evidence 2c.
Collapse
Affiliation(s)
| | | | - Carlos M Atienza
- Instituto de Biomecánica (IBV), Universitat Politècnica de Valencia, Valencia, Spain
- Grupo de Tecnología Sanitaria (GTS-IBV), Instituto de Biomecánica de Valencia-CIBER BBN, Valencia, Spain
| | - Pablo Clavel
- Instituto Clavel, Hospital Quironsalud Barcelona, Barcelona, Spain
| | | | - Carlos Barrios
- Catholic University of Valencia, Saint Vincent Martyr, Valencia, Spain
| | - Leyre Vanaclocha
- Catholic University of Valencia, Saint Vincent Martyr, Valencia, Spain
| |
Collapse
|
3
|
Vanaclocha A, Vanaclocha V, Atienza CM, Clavel P, Jordá-Gómez P, Barrios C, Saiz-Sapena N, Vanaclocha L. Bionate Lumbar Disc Nucleus Prosthesis: Biomechanical Studies in Cadaveric Human Spines. ACS OMEGA 2022; 7:46501-46514. [PMID: 36570209 PMCID: PMC9774399 DOI: 10.1021/acsomega.2c05294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
DESIGN cadaveric spine nucleus replacement study. OBJECTIVE determining Bionate 80A nucleus replacement biomechanics in cadaveric spines. METHODS in cold preserved spines, with ligaments and discs intact, and no muscles, L3-L4, L4-L5, and L5-S1 nucleus implantation was done. Differences between customized and overdimensioned implants were compared. Flexion, extension, lateral bending, and torsion were measured in the intact spine, nucleotomy, and nucleus implantation specimens. Increasing load or bending moment was applied four times at 2, 4, 6, and 8 Nm, twice in increasing mode and twice in decreasing mode. Spine motion was recorded using stereophotogrammetry. Expulsion tests: cyclic compression of 50-550 N for 50,000 cycles, increasing the load until there was extreme flexion, implant extrusion, or anatomical structure collapse. Subsidence tests were done by increasing the compression to 6000 N load. RESULTS nucleotomy increased the disc mobility, which remained unchanged for the adjacent upper level but increased for the lower adjacent one, particularly in lateral bending and torsion. Nucleus implantation, compared to nucleotomy, reduced disc mobility except in flexion-extension and torsion, but intact mobility was no longer recovered, with no effect on upper or lower adjacent segments. The overdimensioned implant, compared to the customized implant, provided equal or sometimes higher mobility. Lamina, facet joint, and annulus removal during nucleotomy caused more damaged than that restored by nucleus implantation. No implant extrusion was observed under compression loads of 925-1068 N as anatomical structures collapsed before. No subsidence or vertebral body fractures were observed under compression loads of 6697.8-6812.3 N. CONCLUSIONS nucleotomized disc and L1-S1 mobility increased moderately after cadaveric spine nucleus implantation compared to the intact status, partly due to operative anatomical damage. Our implant had shallow expulsion and subsidence risks.
Collapse
Affiliation(s)
- Amparo Vanaclocha
- Biomechanical
Engineer, Biomechanics Institute of Valencia, Valencia 46022, Spain
| | | | - Carlos M. Atienza
- Biomechanical
Engineer, Biomechanics Institute of Valencia, Valencia 46022, Spain
| | - Pablo Clavel
- Instituto
Clavel, Hospital Quironsalud Barcelona, Barcelona 08023, Spain
| | - Pablo Jordá-Gómez
- Hospital
General Universitario de Castellón, Castellón de la Plana 12004, Spain
| | - Carlos Barrios
- Catholic
University of Valencia, Saint Vincent Martyr, Valencia 46001, Spain
| | | | - Leyre Vanaclocha
- Medius
Klinik, Ostfildern-Ruit Klinik für Urologie, Hedelfinger Strasse 166, Ostfildern 73760, Germany
| |
Collapse
|
4
|
Abbasi-Ghiri A, Ebrahimkhani M, Arjmand N. Novel force-displacement control passive finite element models of the spine to simulate intact and pathological conditions; comparisons with traditional passive and detailed musculoskeletal models. J Biomech 2022; 141:111173. [PMID: 35705381 DOI: 10.1016/j.jbiomech.2022.111173] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/08/2022] [Accepted: 06/01/2022] [Indexed: 10/18/2022]
Abstract
Passive finite element (FE) models of the spine are commonly used to simulate intact and various pre- and postoperative pathological conditions. Being devoid of muscles, these traditional models are driven by simplistic loading scenarios, e.g., a constant moment and compressive follower load (FL) that do not properly mimic the complex in vivo loading condition under muscle exertions. We aim to develop novel passive FE models that are driven by more realistic yet simple loading scenarios, i.e., in vivo vertebral rotations and pathological-condition dependent FLs (estimated based on detailed musculoskeletal finite element (MS-FE) models). In these novel force-displacement control FE models, unlike the traditional passive FE models, FLs vary not only at different spine segments (T12-S1) but between intact, pre- and postoperative conditions. Intact, preoperative degenerated, and postoperative fused conditions at the L4-L5 segment for five static in vivo activities in upright and flexed postures were simulated by the traditional passive FE, novel force-displacement control FE, and gold-standard detailed MS-FE spine models. Our findings indicate that, when compared to the MS-FE models, the force-displacement control passive FE models could accurately predict the magnitude of disc compression force, intradiscal pressure, annulus maximal von Mises stress, and vector sum of all ligament forces at adjacent segments (L3-L4 and L5-S1) but failed to predict disc shear and facet joint forces. In this regard, the force-displacement control passive FE models were much more accurate than the traditional passive FE models. Clinical recommendations made based on traditional passive FE models should, therefore, be interpreted with caution.
Collapse
Affiliation(s)
- A Abbasi-Ghiri
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - M Ebrahimkhani
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - N Arjmand
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran.
| |
Collapse
|
5
|
Vanaclocha-Saiz A, Vanaclocha V, Atienza CM, Clavel P, Jorda-Gomez P, Barrios C, Vanaclocha L. Finite Element Analysis of a Bionate Ring-Shaped Customized Lumbar Disc Nucleus Prosthesis. ACS APPLIED BIO MATERIALS 2022; 5:172-182. [PMID: 35014829 PMCID: PMC8767544 DOI: 10.1021/acsabm.1c01027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Study design: Biomechanical study of a nucleus replacement
with a finite element model. Objective: To validate a
Bionate 80A ring-shaped nucleus replacement. Methods:
The ANSYS lumbar spine model made from lumbar spine X-rays and magnetic
resonance images obtained from cadaveric spine specimens were used.
All materials were assumed homogeneous, isotropic, and linearly elastic.
We studied three options: intact spine, nucleotomy, and nucleus implant.
Two loading conditions were evaluated at L3-L4, L4-L5, and L5-S1 discs:
a 1000 N axial compression load and this load after the addition of
8 Nm flexion moment in the sagittal plane plus 8 Nm axial rotation
torque. Results: Maximum nucleus implant axial compression
stresses in the range of 16–34 MPa and tensile stress in the
range of 5–16 MPa, below Bionate 80A resistance were obtained.
Therefore, there is little risk of permanent implant deformation or
severe damage under normal loading conditions. Nucleotomy increased
segment mobility, zygapophyseal joint and end plate pressures, and
annulus stresses and strains. All these parameters were restored satisfactorily
by nucleus replacement but never reached the intact status. In addition,
annulus stresses and strains were lower with the nucleus implant than
in the intact spine under axial compression and higher under complex
loading conditions. Conclusions: Under normal loading
conditions, there is a negligible risk of nucleus replacement, permanent
deformation or severe damage. Nucleotomy increased segmental mobility,
zygapophyseal joint pressures, and annulus stresses and strains. Nucleus
replacement restored segmental mobility and zygapophyseal joint pressures
close to the intact spine. End plate pressures were similar for the
intact and nucleus implant conditions under both loading modes. Manufacturing
customized nucleus implants is considered feasible, as satisfactory
biomechanical performance is confirmed.
Collapse
Affiliation(s)
- Amparo Vanaclocha-Saiz
- Escuela de Doctorado, Universitat Politècnica de Valencia, Camí de Vera, s/n, 46022 Valencia, Spain
| | - Vicente Vanaclocha
- University of Valencia, Avenida de Blasco Ibáñez, 13, 46010 Valencia, Spain
| | - Carlos M Atienza
- Instituto de Biomecánica (IBV), Universitat Politècnica de Valencia, Camí de Vera, s/n, 46022 Valencia. Spain.,Instituto de Biomecánica de Valencia-CIBER BBN, Grupo de Tecnología Sanitaria (GTS-IBV), Camí de Vera, s/n, 46022 Valencia, Spain
| | - Pablo Clavel
- Instituto Clavel, Hospital Quironsalud Barcelona, Plaça d'Alfonso Comín, 5, 08023 Barcelona, Spain
| | - Pablo Jorda-Gomez
- Hospital Politècnic i Universitari La Fe, Avinguda de Fernando Abril Martorell, 106, 46026 Valencia, Spain
| | - Carlos Barrios
- Catholic University of Valencia, Saint Vincent Martyr, Carrer de Quevedo, 2, 46001 Valencia, Spain
| | - Leyre Vanaclocha
- University College London, London, Gower St, London WC1E 6BT, U.K
| |
Collapse
|
6
|
Penolazzi L, Pozzobon M, Bergamin LS, D'Agostino S, Francescato R, Bonaccorsi G, De Bonis P, Cavallo M, Lambertini E, Piva R. Extracellular Matrix From Decellularized Wharton's Jelly Improves the Behavior of Cells From Degenerated Intervertebral Disc. Front Bioeng Biotechnol 2020; 8:262. [PMID: 32292779 PMCID: PMC7118204 DOI: 10.3389/fbioe.2020.00262] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/13/2020] [Indexed: 12/11/2022] Open
Abstract
Regenerative therapies for intervertebral disc (IVD) injuries are currently a major challenge that is addressed in different ways by scientists working in this field. Extracellular matrix (ECM) deriving from decellularized non-autologous tissues has been established as a biomaterial with remarkable regenerative capacity and its potential as a therapeutic agent is rising. In the present study, we investigated the potential of decellularized Wharton’s jelly matrix (DWJM) from human umbilical cord to act as an ECM-based scaffold for IVD cell culturing. An efficient detergent-enzymatic treatment (DET) was used to produce DWJM maintaining its native microarchitecture. Afterward, immunofluorescence, biochemical assays and electron microscopy analysis showed that DWJM was able to produce sizeable 3D cell aggregates, when combined with human mesenchymal stromal cells isolated from WJ (MSCs) and IVD cells. These latter cells are characterized by the loss of their chondrocyte-like phenotype since they have been isolated from degenerated IVD and in vitro expanded to further de-differentiate. While the effect exerted by DWJM on MSCs was essentially the induction of proliferation, conversely, on IVD cells the DWJM promoted cell differentiation toward a discogenic phenotype. Notably, for the first time, the ability of DWJM to improve the degenerated phenotype of human IVD cells was demonstrated, showing that the mere presence of the matrix maintained the viability of the cells, and positively affected the expression of critical regulators of IVD homeostasis, such as SOX2, SOX9, and TRPS1 transcription factors at specific culture time. Our data are in line with the hypothesis that the strengthening of cell properties in terms of viability and expression of specific proteins at precise times represents an important condition in the perspective of guiding the recovery of cellular functionality and triggering regenerative potential. Currently, there are no definitive surgical or pharmacological treatments for IVD degeneration (IDD) able to restore the disc structure and function. Therefore, the potential of DWJM to revert degenerated IVD cells could be exploited in the next future an ECM-based intradiscal injectable therapeutic.
Collapse
Affiliation(s)
- Letizia Penolazzi
- Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Michela Pozzobon
- Stem Cells and Regenerative Medicine Lab, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padua, Italy.,Department of Women and Children Health, University of Padova, Padua, Italy
| | | | - Stefania D'Agostino
- Stem Cells and Regenerative Medicine Lab, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padua, Italy.,Department of Women and Children Health, University of Padova, Padua, Italy
| | - Riccardo Francescato
- Stem Cells and Regenerative Medicine Lab, Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padua, Italy
| | - Gloria Bonaccorsi
- Section of Obstetrics and Gynecology, Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, and S. Anna University Hospital, Ferrara, Italy
| | - Pasquale De Bonis
- Department of Neurosurgery, University of Ferrara, and S. Anna University Hospital, Ferrara, Italy
| | - Michele Cavallo
- Department of Neurosurgery, University of Ferrara, and S. Anna University Hospital, Ferrara, Italy
| | - Elisabetta Lambertini
- Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy
| | - Roberta Piva
- Department of Biomedical and Specialty Surgical Sciences, University of Ferrara, Ferrara, Italy
| |
Collapse
|