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Wilke HJ, Sciortino V. The past, present, and the future of disc nucleus replacement. A systematic review of a large diversity of ideas and experiences. Biomaterials 2024; 312:122717. [PMID: 39121730 DOI: 10.1016/j.biomaterials.2024.122717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 07/10/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
Disc nucleus replacement (NR) is a challenging surgical technique used as a medical treatment for early-stage disc herniation to restore disc height and the biomechanical function of a motion segment, which may reduce low back pain. The surgical procedure involves the removal and replacement of the degenerated nucleus pulposus with a substitute by accessing the annulus fibrosos via a created hole. Over the decades, nucleus replacement has been an important issue, leading to the development of different substitute alternatives. The first ideas are dated to the 1950s and since then, more than a hundred nucleus replacement concepts can be identified. There were numerous attempts and several clinical trials; however, after more than 70 years of research, no gold standard for nucleus pulposus replacement has been identified. This review aims to collect the different nucleus replacements reported in the literature, thus understanding what failed, what could be improved and what are the opportunities for the future. A systematic review of the literature was performed using a keyword-based search on PubMed, Web of Science, and Scopus databases to detect all nucleus replacements presented in the past by clinicians and engineers. Several studies were extracted from which the main nucleus replacements over the years were investigated, including the ones that received CE mark, FDA approval, or IDE approval and, also those involved in clinical trials. A total of 116 studies were included in this review. The extracted data concern the nucleus replacements proposed over the years to create a historical background as complete as possible, including their mechanical and biomechanical characterization and the clinical trials conducted over the years. Nucleus disc arthroplasty has been explored for many years. Unfortunately, even today there is still nothing safe and definitive in this surgical practice. This review provides an overview of the nucleus replacement history. A breakthrough could be the improvements in technologies for the annulus fibrous closing or sealing and the tissue engineering and medical regenerative techniques which could certainly ensure a higher NR implantation success rate in the future of this clinical treatment. It is not yet clear what is the future of this clinical practice. Only scientific research can answer the question: is the nucleus replacement still a possible clinical solution?
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Affiliation(s)
- Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, Ulm University, Helmholtzstrabe 14, Ulm 89081, Germany.
| | - Vincenza Sciortino
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, Ulm University, Helmholtzstrabe 14, Ulm 89081, Germany; University of Palermo, Department of Engineering, Viale delle Scienze, 90128 Palermo, Italy
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Rahman T, Kibble MJ, Harbert G, Smith N, Brewer E, Schaer TP, Newell N. Comparison of four in vitro test methods to assess nucleus pulposus replacement device expulsion risk. JOR Spine 2024; 7:e1332. [PMID: 38655007 PMCID: PMC11037461 DOI: 10.1002/jsp2.1332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 03/22/2024] [Accepted: 03/27/2024] [Indexed: 04/26/2024] Open
Abstract
Background Nucleus replacement devices (NRDs) are not routinely used in clinic, predominantly due to the risk of device expulsion. Rigorous in vitro testing may enable failure mechanisms to be identified prior to clinical trials; however, current testing standards do not specify a particular expulsion test. Multiple methods have therefore been developed, complicating comparisons between NRD designs. Thus, this study assessed the effectiveness of four previously reported expulsion testing protocols; hula-hoop (Protocol 1), adapted hula-hoop (Protocol 2), eccentric cycling (Protocol 3), and ramp to failure (Protocol 4), applied to two NRDs, one preformed and one in situ curing. Methods Nucleus material was removed from 40 bovine tail intervertebral disks. A NRD was inserted posteriorly into each cavity and the disks were subjected to one of four expulsion protocols. Results NRD response was dependent on both the NRD design and the loading protocol. Protocol 1 resulted in higher migration and earlier failure rates compared to Protocol 2 in both NRDs. The preformed NRD was more likely to migrate when protocols incorporated rotation. The NRDs had equal migration (60%) and expulsion (60%) rates when using unilateral bending and ramp testing. Combining the results of multiple tests revealed complimentary information regarding the NRD response. Conclusions Adapted hula-hoop (Protocol 2) and ramp to failure (Protocol 4), combined with fluoroscopic analysis, revealed complimentary insights regarding migration and failure risk. Therefore, when adopting the surgical approach and animal model used in this study, it is recommended that NRD performance be assessed using both a cyclic and ramp loading protocol.
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Affiliation(s)
- Tamanna Rahman
- Department of BioengineeringImperial College LondonLondonUK
- Biomechanics Group, Department of Mechanical EngineeringImperial College LondonLondonUK
| | | | | | - Nigel Smith
- Division of Surgery and Interventional ScienceUniversity College LondonStanmoreUK
| | - Erik Brewer
- Department of Biomedical EngineeringRowan UniversityGlassboroNew JerseyUSA
| | - Thomas P. Schaer
- Department of Clinical Studies New Bolton CenterUniversity of Pennsylvania School of Veterinary MedicineKennett SquarePennsylvaniaUSA
| | - Nicolas Newell
- Department of BioengineeringImperial College LondonLondonUK
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Wilke HJ, Fuchs H, Benz K, Mollenhauer J, Gaissmaier C, Heuer F, Neidlinger-Wilke C. The Injection of Gels Through an Intact Annulus Maintains Biomechanical Performance without Extrusion Risk. Gels 2024; 10:269. [PMID: 38667688 PMCID: PMC11049287 DOI: 10.3390/gels10040269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
For autologous-disc-derived chondrocyte transplantation (ADCT) a transglutaminase crosslinked gelatine gel and an albumin hyaluronic acid gel, crosslinked with bis-thio-polyethylene glycol, were injected through a syringe into a degenerated intervertebral disc, where they solidified in situ. This biomechanical in vitro study with lumbar bovine motion segments evaluated disc height changes, motion characteristics in a quasi-static spine loading simulators, and the potential extrusion risk of these biomaterials in a complex dynamic multi-axial loading set-up with 100,000 loading cycles. After the injection and formation of the gel in the center of the nucleus, the disc height increase was about 0.3 mm. During cyclic testing, a gradual decrease in height could be detected due to viscoelastic effects and fluid loss. No gel extrusion could be observed for all specimens during the entire test procedure. A macroscopic inspection after dissections showed an accumulation of the solidified gel in the center of the nucleus. The results demonstrate that the injection of in situ solidifying gels through the intact annulus allows for the stable maintenance of the injected gel at the target location, with high potential for use as a suitable scaffold to anchor therapeutically applied cells for disc regeneration within the treated nucleus pulposus.
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Affiliation(s)
- Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, 89081 Ulm, Germany (C.N.-W.)
| | - Holger Fuchs
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, 89081 Ulm, Germany (C.N.-W.)
| | - Karin Benz
- NMI Natural and Medical Sciences Institute, The University of Tübingen, 72770 Reutlingen, Germany; (K.B.)
- TETEC Tissue Engineering Technologies AG, 72770 Reutlingen, Germany;
| | - Juergen Mollenhauer
- NMI Natural and Medical Sciences Institute, The University of Tübingen, 72770 Reutlingen, Germany; (K.B.)
| | | | - Frank Heuer
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, 89081 Ulm, Germany (C.N.-W.)
| | - Cornelia Neidlinger-Wilke
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, 89081 Ulm, Germany (C.N.-W.)
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Beall DP, Amirdelfan K, Nunley PD, Phillips TR, Imaz Navarro LC, Spath A. Hydrogel Augmentation of the Lumbar Intervertebral Disc: An Early Feasibility Study of a Treatment for Discogenic Low Back Pain. J Vasc Interv Radiol 2024; 35:51-58.e1. [PMID: 37758022 DOI: 10.1016/j.jvir.2023.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 09/12/2023] [Accepted: 09/17/2023] [Indexed: 10/03/2023] Open
Abstract
PURPOSE To assess the safety and effectiveness of intradiscal hydrogel in patients with chronic low back pain (CLBP) due to degenerative disc disease (DDD) refractory to conventional medical management. MATERIALS AND METHODS Twenty patients aged 22-69 years with numerical rating scale (NRS) pain of ≥4 were enrolled. All patients with CLBP resulting from DDD confirmed by imaging and discography received injections of hydrogel (Hydrafil Intervertebral Disc Augmentation; ReGelTec, Baltimore, Maryland) at 1 or 2 lumbar levels (29 levels treated) from August to December 2020. The primary safety end point was freedom from serious adverse events (SAEs). The primary performance end point was successful gel delivery into the desired disc. Patients were also assessed on the NRS as well as the Oswestry disability index (ODI). RESULTS Nineteen patients were followed up at a mean of 131 days, and 1 patient was lost to follow-up. Preliminary results showed significant reductions in median NRS back pain from 7 (range 4-10) to 1 (range 0-8) (P <.0001) and median ODI scores from 54 (range 22-58) to 2 (range 0-58) (P <.0001) at 6 months of follow-up. There were 5 SAEs, and 4 of the 2 were determined to be associated with treatment. CONCLUSIONS This early feasibility study showed that the hydrogel implant was safe with no persistently symptomatic SAEs, and demonstrated effectiveness with significant reduction in pain and improvement in function when used to treat painful DDD and CLBP.
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Affiliation(s)
- Douglas P Beall
- Comprehensive Specialty Care, Interventional Pain/Interventional Radiology, Edmond, Oklahoma
| | - Kasra Amirdelfan
- IPM Medical Group, Interventional Pain, Walnut Creek, California
| | - Pierce D Nunley
- Department of Orthopedic Surgery, Spine Institute of Louisiana, Shreveport, Los Angeles
| | - Tyler R Phillips
- Comprehensive Specialty Care, Interventional Pain/Interventional Radiology, Edmond, Oklahoma.
| | | | - Alfonso Spath
- Interventional Radiology, Cediul Imagenes Diagnostics Y Terapeuticas, Barranquilla, Columbia
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Li ZL, Lu Q, Honiball JR, Wan SHT, Yeung KWK, Cheung KMC. Mechanical characterization and design of biomaterials for nucleus pulposus replacement and regeneration. J Biomed Mater Res A 2023; 111:1888-1902. [PMID: 37555381 DOI: 10.1002/jbm.a.37593] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/23/2023] [Indexed: 08/10/2023]
Abstract
Biomaterials for nucleus pulposus (NP) replacement and regeneration have great potential to restore normal biomechanics in degenerated intervertebral discs following nucleotomy. Mechanical characterizations are essential for assessing the efficacy of biomaterial implants for clinical applications. While traditional compression tests are crucial to quantify various modulus values, relaxation behaviors and fatigue resistance, rheological measurements should also be conducted to investigate the viscoelastic properties, injectability, and overall stability upon deformation. To recapitulate the physiological in vivo environment, the use of spinal models is necessary to evaluate the risk of implant extrusion and the restoration of biomechanics under different loading conditions. When designing devices for NP replacement, injectable materials are ideal to fully fill the nucleus cavity and prevent implant migration. In addition to achieving biocompatibility and desirable mechanical characteristics, biomaterial implants should be optimized to avoid implant extrusion or re-herniation post-operatively. This review discusses the most commonly used testing protocols for assessing mechanical properties of biomaterial implants and serves as reference material for enabling researchers to characterize NP implants through a unified approach whereby newly developed biomaterials may be compared and contrasted to existing devices.
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Affiliation(s)
- Zhuoqi Lucas Li
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
| | - Qiuji Lu
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
| | - John Robert Honiball
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
| | - Sandra Hiu-Tung Wan
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
| | - Kelvin Wai-Kwok Yeung
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
- Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma, The University of Hong Kong Shenzhen Hospital, Shenzhen, China
| | - Kenneth Man-Chee Cheung
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong, China
- Department of Orthopaedics and Traumatology, The University of Hong Kong-Shenzhen Hospital, Shenzhen, China
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Ying Y, Cai K, Cai X, Zhang K, Qiu R, Jiang G, Luo K. Recent advances in the repair of degenerative intervertebral disc for preclinical applications. Front Bioeng Biotechnol 2023; 11:1259731. [PMID: 37811372 PMCID: PMC10557490 DOI: 10.3389/fbioe.2023.1259731] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Accepted: 09/14/2023] [Indexed: 10/10/2023] Open
Abstract
The intervertebral disc (IVD) is a load-bearing, avascular tissue that cushions pressure and increases flexibility in the spine. Under the influence of obesity, injury, and reduced nutrient supply, it develops pathological changes such as fibular annulus (AF) injury, disc herniation, and inflammation, eventually leading to intervertebral disc degeneration (IDD). Lower back pain (LBP) caused by IDD is a severe chronic disorder that severely affects patients' quality of life and has a substantial socioeconomic impact. Patients may consider surgical treatment after conservative treatment has failed. However, the broken AF cannot be repaired after surgery, and the incidence of re-protrusion and reoccurring pain is high, possibly leading to a degeneration of the adjacent vertebrae. Therefore, effective treatment strategies must be explored to repair and prevent IDD. This paper systematically reviews recent advances in repairing IVD, describes its advantages and shortcomings, and explores the future direction of repair technology.
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Affiliation(s)
- Yijian Ying
- Health Science Center, Ningbo University, Ningbo, Zhejiang, China
| | - Kaiwen Cai
- Department of Orthopaedics, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang, China
| | - Xiongxiong Cai
- Health Science Center, Ningbo University, Ningbo, Zhejiang, China
| | - Kai Zhang
- Department of Orthopaedics, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang, China
| | - Rongzhang Qiu
- Health Science Center, Ningbo University, Ningbo, Zhejiang, China
| | - Guoqiang Jiang
- Department of Orthopaedics, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang, China
| | - Kefeng Luo
- Department of Orthopaedics, The First Affiliated Hospital of Ningbo University, Ningbo, Zhejiang, China
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Wang L, Jin K, Li N, Xu P, Yuan H, Ramaraju H, Hollister SJ, Fan Y. Innovative design of minimal invasive biodegradable poly(glycerol-dodecanoate) nucleus pulposus scaffold with function regeneration. Nat Commun 2023; 14:3865. [PMID: 37391454 PMCID: PMC10313828 DOI: 10.1038/s41467-023-39604-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 06/21/2023] [Indexed: 07/02/2023] Open
Abstract
Minimally invasive biodegradable implants with regeneration have been a frontier trend in clinic. Degeneration of nucleus pulposus (NP) is irreversible in most of spine diseases, and traditional spinal fusion or discectomy usually injure adjacent segments. Here, an innovative minimally invasive biodegradable NP scaffold with function regeneration inspired by cucumber tendril is developed using shape memory polymer poly(glycerol-dodecanoate) (PGD), whose mechanical property is controlled to the similar with human NP by adjusting synthetic parameters. The chemokine stromal cell-derived factor-1α (SDF-1α) is immobilized to the scaffold recruiting autologous stem cells from peripheral tissue, which has better ability of maintaining disc height, recruiting autologous stem cells, and inducing regeneration of NP in vivo compared to PGD without chemokine group and hydrogel groups significantly. It provides an innovative way to design minimally invasive implants with biodegradation and functional recovery, especially for irreversible tissue injury, including NP, cartilage and so on.
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Affiliation(s)
- Lizhen Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Kaixiang Jin
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Nan Li
- Department of Spine Surgery, Beijing Jishuitan Hospital, The Fourth Clinical Medical College of Peking University, Beijing, 100035, China
| | - Peng Xu
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Hao Yuan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Harsha Ramaraju
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA, 30332, USA
| | - Scott J Hollister
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA, 30332, USA
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China.
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Rahman T, Baxan N, Murray RT, Tavana S, Schaer TP, Smith N, Bull J, Newell N. An in vitro comparison of three nucleus pulposus removal techniques for partial intervertebral disc replacement: An ultra-high resolution MRI study. JOR Spine 2023; 6:e1232. [PMID: 37361334 PMCID: PMC10285766 DOI: 10.1002/jsp2.1232] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/03/2022] [Indexed: 10/19/2023] Open
Abstract
Background Nuclectomy, also known as nucleotomy, is a percutaneous surgical procedure performed to remove nucleus material from the center of the disc. Multiple techniques have been considered to perform a nuclectomy, however, the advantages and disadvantages of each are not well understood. Aims This in vitro biomechanical investigation on human cadaveric specimens aimed to quantitatively compare three nuclectomy techniques performed using an automated shaver, rongeurs, and laser. Material & Methods Comparisons were made in terms of mass, volume and location of material removal, changes in disc height, and stiffness. Fifteen vertebra-disc-vertebra lumbar specimens were acquired from six donors (40 ± 13 years) and split into three groups. Before and after nucleotomy axial mechanical tests were performed and T2-weighted 9.4T MRIs were acquired for each specimen. Results When using the automated shaver and rongeurs similar volumes of disc material were removed (2.51 ± 1.10% and 2.76 ± 1.39% of the total disc volume, respectively), while considerably less material was removed using the laser (0.12 ± 0.07%). Nuclectomy using the automated shaver and rongeurs significantly reduced the toe-region stiffness (p = 0.036), while the reduction in the linear region stiffness was significant only for the rongeurs group (p = 0.011). Post-nuclectomy, 60% of the rongeurs group specimens showed changes in the endplate profile while 40% from the laser group showed subchondral marrow changes. Discussion From the MRIs, homogeneous cavities were seen in the center of the disc when using the automated shaver. When using rongeurs, material was removed non-homogeneously both from the nucleus and annulus regions. Laser ablation formed small and localized cavities suggesting that the technique is not suitable to remove large volumes of material unless it is developed and optimized for this application. Conclusion The results demonstrate that both rongeurs and automated shavers can be used to remove large volumes of NP material but the reduced risk of collateral damage to surrounding tissues suggests that the automated shaver may be more suitable.
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Affiliation(s)
- Tamanna Rahman
- Biomechanics Group, Department of Mechanical EngineeringImperial College LondonLondonUK
- Department of BioengineeringImperial College LondonLondonUK
| | - Nicoleta Baxan
- Biological Imaging Centre, Central Biomedical ServicesImperial College London, Hammersmith Hospital CampusLondonUK
| | - Robert T. Murray
- Femtosecond Optics Group, Blackett Laboratory, Department of PhysicsImperial College LondonLondonUK
| | - Saman Tavana
- Biomechanics Group, Department of Mechanical EngineeringImperial College LondonLondonUK
- Department of BioengineeringImperial College LondonLondonUK
| | - Thomas P. Schaer
- Department of Clinical Studies, School of Veterinary Medicine, New Bolton CenterUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Nigel Smith
- Division of Surgery and Interventional ScienceUniversity College LondonStanmoreUK
| | - Jonathan Bull
- Department of NeurosurgeryBARTS Health NHS TrustLondonUK
| | - Nicolas Newell
- Department of BioengineeringImperial College LondonLondonUK
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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.
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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
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10
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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.
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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
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11
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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
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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.
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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
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12
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Di Pauli von Treuheim T, Zengerle L, Hecht AC, Iatridis JC, Wilke HJ. Does the neutral zone quantification method matter? Efficacy of evaluating neutral zone during destabilization and restabilization in human spine implant testing. J Biomech 2021; 129:110756. [PMID: 34619461 DOI: 10.1016/j.jbiomech.2021.110756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/02/2021] [Accepted: 09/16/2021] [Indexed: 11/18/2022]
Abstract
Neutral zone (NZ) is an important biomechanical parameter when evaluating spinal instability following destabilizing and restabilizing events, with particular relevance for implant efficacy testing. It remains unclear what NZ calculation methods are most sensitive at capturing NZ changes across treatment conditions and a direct comparison is needed. The purpose of this study was to determine the most sensitive method at quantifying instability in human spines. Six cadaveric lumbar motion segments were subjected to a repeated measures implant testing schema of four sequential conditions: (1) Intact, (2) injury by herniation, (3) device implantation, (4) long-term cyclic fatigue loading. NZ was expected to increase after destabilization (steps 2 & 4) and decrease after restabilization (step 3). NZ methods compared in this study were: trilinear (TL), double sigmoid (DS), zero load (ZL), stiffness threshold (ST), and extrapolated elastic zone (EEZ). TL, ZL, and EEZ identified statistically significant NZ differences after each condition in flexion/extension and lateral bending. The ZL method also captured differences in axial rotation. All methods identified expected NZ changes after destabilization and restabilization, except DS in axial rotation. The TL, ZL, and EEZ methods were the most sensitive methods with this human cadaveric dataset. Future investigations comparing methods with additional datasets will clarify outcome generalizability and determine what curve profiles are most suitable for DS and ST methods. Understanding the applicability of NZ methods can enhance rigor and reliability of spinal instability measurements when quantifying the efficacy of novel implants and permits insight into clinically relevant biomechanical changes.
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Affiliation(s)
- T Di Pauli von Treuheim
- One Gustave Levy Place, Box 1188, Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - L Zengerle
- Institute of Orthopedic Research and Biomechanics, Center for Trauma Research Ulm, Ulm University, Ulm, Germany.
| | - A C Hecht
- One Gustave Levy Place, Box 1188, Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - J C Iatridis
- One Gustave Levy Place, Box 1188, Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| | - H J Wilke
- Institute of Orthopedic Research and Biomechanics, Center for Trauma Research Ulm, Ulm University, Ulm, Germany.
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13
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Wang Y, Kang J, Guo X, Zhu D, Liu M, Yang L, Zhang G, Kang X. Intervertebral Disc Degeneration Models for Pathophysiology and Regenerative Therapy -Benefits and Limitations. J INVEST SURG 2021; 35:935-952. [PMID: 34309468 DOI: 10.1080/08941939.2021.1953640] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Aim:This review summarized the recent intervertebral disc degeneration (IDD) models and described their advantages and potential disadvantages, aiming to provide an overview for the current condition of IDD model establishment and new ideas for new strategies development of the treatment and prevention of IDD.Methods:The database of PubMed was searched up to May 2021 with the following search terms: nucleus pulposus, annulus fibrosus, cartilage endplate, intervertebral disc(IVD), intervertebral disc degeneration, animal model, organ culture, bioreactor, inflammatory reaction, mechanical stress, pathophysiology, epidemiology. Any IDD model-related articles were collected and summarized.Results:The best IDD model should have the features of repeatability, measurability and controllability. There are a lot of aspects to be considered in the selection of animals. Mice, rats and rabbits are low-cost and easy to access. However, their IVD size and shape are more different from human anatomy than pigs, cattle, sheep and goats. Organ culture models and animal models are two options in model establishment for IDD. The IVD organ culture model can put the studying variables into the controllable system for transitional research. Unlike the animal model, the organ culture model can only be used to evaluate the short-term effects and it is not applicable in simulating the complex process of IDD. Similarly, the animal models induced by different methods also have their advantages and disadvantages. For studying the mechanism of IDD and the corresponding treatment and prevention strategies, the selection of model should be individualized based on the purpose of each study.Conclusions:Various models have different characteristics and scope of application due to their different rationales and methods of construction. Currently, there is no experimental model that can perfectly mimic the degenerative process of human IVD. Personalized selection of appropriate model based on study purpose and experimental designing can enhance the possibility to obtain reliable and real results.
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Affiliation(s)
- Yidian Wang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Jihe Kang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Xudong Guo
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Daxue Zhu
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Mingqiang Liu
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Liang Yang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Guangzhi Zhang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China
| | - Xuewen Kang
- The Second Clinical Medical College, Lanzhou University, Lanzhou, P.R. China.,Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, P.R. China.,The International Cooperation Base of Gansu Province for The Pain Research in Spinal Disorders, Gansu, P.R. China
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