Stiffness Matters

Peterson, Joshua; Chlebek, Carolyn; Clough, Ashley M; Wells, Alexandra K.; Batzinger, Kathleen E; Houston, John M.; Kradinova, Katerina; Glennon, Joseph C.; DiRisio, Darryl J.; Ledet, Eric H.

doi:10.1097/brs.0000000000002644

Cited by 14 publications

(4 citation statements)

References 30 publications

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“…Previous cadaveric studies of cervical spine have suggested that the application of anterior cervical plate could reverse the graft loads and excessively loads the bone graft in extension, but unloads the graft in flexion ( Foley et al, 1999 ; DiAngelo et al, 2000 ). Peterson et al (2018 ) used a validated custom force-sensing interbody implant to measure interbody loads in a sheep ACDF model in real time during fusion. They found that the average change in interbody force magnitude from full extension to full flexion decreased significantly during fusion.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the mechanical loading on the instrumentation may be a promising indicator to evaluate the fusion status after ACDF, which has the potential to advance current diagnostic methods for interbody fusion. Several animal experiments suggested that the mechanical load on the spinal instrumentation may have the potential to reflect the fusion process and evaluated the stability of implant ( Takahata et al, 2005 ; Ferrara et al, 2007 ; Ferrara et al, 2008 ; Peterson et al, 2018 ). However, the inability to precisely measure the mechanical load of interbody implant in human body remains a significant barrier to determine the feasibility of reflecting the status of fusion through load changes on the instrumentation.…”

Section: Introductionmentioning

confidence: 99%

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Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study

Shen

Yang

Líu

et al. 2022

Front. Bioeng. Biotechnol.

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Introduction: Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical procedure in the treatment of cervical radiculopathy and myelopathy. A solid interbody fusion is of critical significance in achieving satisfactory outcomes after ACDF. However, the current radiographic techniques to determine the degree of fusion are inaccurate and radiative. Several animal experiments suggested that the mechanical load on the spinal instrumentation could reflect the fusion process and evaluated the stability of implant. This study aims to investigate the biomechanical changes during the fusion process and explore the feasibility of reflecting the fusion status after ACDF through the load changes borne by the interbody fusion cage.Methods: The computed tomography (CT) scans preoperatively, immediately after surgery, at 3 months, and 6 months follow-up of patients who underwent ACDF at C5/6 were used to construct the C2–C7 finite element (FE) models representing different courses of fusion stages. A 75-N follower load with 1.0-Nm moments was applied to the top of C2 vertebra in the models to simulate flexion, extension, lateral bending, and axial rotation with the C7 vertebra fixed. The Von Mises stress at the surfaces of instrumentation and the adjacent intervertebral disc and force at the facet joints were analyzed.Results: The facet contact force at C5/6 suggested a significantly stepwise reduction as the fusion proceeded while the intradiscal pressure and facet contact force of adjacent levels changed slightly. The stress on the surfaces of titanium plate and screws significantly decreased at 3 and 6 months follow-up. A markedly changed stress distribution in extension among three models was noted in different fusion stages. After solid fusion is achieved, the stress was more uniformly distributed interbody fusion in all loading conditions.Conclusions: Through a follow-up study of 6 months, the stress on the surfaces of cervical instrumentation remarkably decreased in all loading conditions. After solid intervertebral fusion formed, the stress distributions on the surfaces of interbody cage and screws were more uniform. The stress distribution in extension altered significantly in different fusion status. Future studies are needed to develop the interbody fusion device with wireless sensors to achieve longitudinal real-time monitoring of the stress distribution during the course of fusion.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study

Shen

Yang

Líu

et al. 2022

Front. Bioeng. Biotechnol.

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“…This PDF file includes: Materials and Methods Fig. S1 to S14 Table S1 References (48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60) Other Supplementary Material for this manuscript includes the following:…”

Section: Supplementary Materialsmentioning

confidence: 99%

Tension-activated nanofiber patches delivering an anti-inflammatory drug improve repair in a goat intervertebral disc herniation model

Peredo,

Gullbrand,

Friday

et al. 2023

Sci. Transl. Med.

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Conventional microdiscectomy treatment for intervertebral disc herniation alleviates pain but does not repair the annulus fibrosus, resulting in a high incidence of recurrent herniation and persistent dysfunction. The lack of repair and the acute inflammation that arise after injury can further compromise the disc and result in disc-wide degeneration in the long term. To address this clinical need, we developed tension-activated repair patches (TARPs) for annulus fibrosus repair and local delivery of the anti-inflammatory factor anakinra (a recombinant interleukin-1 receptor antagonist). TARPs transmit physiologic strain to mechanically activated microcapsules embedded within the patch, which release encapsulated bioactive molecules in direct response to spinal loading. Mechanically activated microcapsules carrying anakinra were loaded into TARPs, and the effects of TARP-mediated annular repair and anakinra delivery were evaluated in a goat model of annular injury in the cervical spine. TARPs integrated with native tissue and provided structural reinforcement at the injury site that prevented aberrant disc-wide remodeling resulting from detensioning of the annular fibrosus. The delivery of anakinra by TARP implantation increased matrix deposition and retention at the injury site and improved maintenance of disc extracellular matrix. Anakinra delivery additionally attenuated the inflammatory response associated with TARP implantation, decreasing osteolysis in adjacent vertebrae and preserving disc cellularity and matrix organization throughout the annulus fibrosus. These results demonstrate the therapeutic potential of TARPs for the treatment of intervertebral disc herniation.

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“…Many in vivo studies do not restrict the animal movement or attach invasive instruments such as rigs or jigs. Such rigs or jigs have included the manipulation of bone screws/pins to alter the position or load applied to the animal vertebrae to more accurately understand the effects of specific loads 130 but these may not represent the same loads encountered during daily activities such as walking. Furthermore, the risk of infection on open wounds and the correct positioning of mechanical test fixtures is a challenge.…”

Section: In Vivo Modelsmentioning

confidence: 99%

The role of biomechanical factors in models of intervertebral disc degeneration across multiple length scales

Lazaro-Pacheco,

Mohseni,

Rudd

et al. 2023

APL Bioengineering

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Low back pain is the leading cause of disability, producing a substantial socio-economic burden on healthcare systems worldwide. Intervertebral disc (IVD) degeneration is a primary cause of lower back pain, and while regenerative therapies aimed at full functional recovery of the disc have been developed in recent years, no commercially available, approved devices or therapies for the regeneration of the IVD currently exist. In the development of these new approaches, numerous models for mechanical stimulation and preclinical assessment, including in vitro cell studies using microfluidics, ex vivo organ studies coupled with bioreactors and mechanical testing rigs, and in vivo testing in a variety of large and small animals, have emerged. These approaches have provided different capabilities, certainly improving the preclinical evaluation of these regenerative therapies, but challenges within the research environment, and compromises relating to non-representative mechanical stimulation and unrealistic test conditions, remain to be resolved. In this review, insights into the ideal characteristics of a disc model for the testing of IVD regenerative approaches are first assessed. Key learnings from in vivo, ex vivo, and in vitro IVD models under mechanical loading stimulation to date are presented alongside the merits and limitations of each model based on the physiological resemblance to the human IVD environment (biological and mechanical) as well as the possible feedback and output measurements for each approach. When moving from simplified in vitro models to ex vivo and in vivo approaches, the complexity increases resulting in less controllable models but providing a better representation of the physiological environment. Although cost, time, and ethical constraints are dependent on each approach, they escalate with the model complexity. These constraints are discussed and weighted as part of the characteristics of each model.

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Stiffness Matters

Abstract: N/A.

Cited by 14 publications

References 30 publications

Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study

Biomechanical Evaluation of Intervertebral Fusion Process After Anterior Cervical Discectomy and Fusion: A Finite Element Study

Tension-activated nanofiber patches delivering an anti-inflammatory drug improve repair in a goat intervertebral disc herniation model

The role of biomechanical factors in models of intervertebral disc degeneration across multiple length scales

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