Design of a Lumbar Interspinous Fixation Device for Minimally Invasive Surgery and Spine Motion Stabilization

Heo, Minhyeok; Yun, Jihwan; Park, Sang-Hu; Choi, Yoon Suk; Lee, Sang-Soo; Park, Seonghun

doi:10.1007/s40846-019-00485-8

Cited by 3 publications

(4 citation statements)

References 37 publications

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“…While different clinical and biomechanical experimental studies were performed to evaluate the applicability of PEEK semirigid rods for non-fusion surgeries ( Chou et al, 2015 ; Huang et al, 2016 ; Li et al, 2016 ; Selim et al, 2018 ), finite element (FE) modeling can be utilized, in parallel, as a practical tool for non-invasive investigations. Abundant FE studies have investigated the effect of different diseases/disorders ( Schmidt et al, 2007b ; Bashkuev et al, 2018 ; Ozkal et al, 2020 ) and relevant treatment modalities and techniques ( Nikitovic et al, 2017 ; Rijsbergen et al, 2018 ; Zhang et al, 2018a ; Heo et al, 2020 ) in lumbar spine. However, most of the available spinal FE models in the literature are limited to a single geometry which can cause uncertainty in the results and affect the reliability of FE model prediction for clinical application ( Laville et al, 2009 ; Nikkhoo et al, 2019 , 2020 ; Liu et al, 2020 ; Ozkal et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Biomechanical Investigation Between Rigid and Semirigid Posterolateral Fixation During Daily Activities: Geometrically Parametric Poroelastic Finite Element Analyses

Nikkhoo

Chen

et al. 2021

Front. Bioeng. Biotechnol.

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While spinal fusion using rigid rods remains the gold standard treatment modality for various lumbar degenerative conditions, its adverse effects, including accelerated adjacent segment disease (ASD), are well known. In order to better understand the performance of semirigid constructs using polyetheretherketone (PEEK) in fixation surgeries, the objective of this study was to analyze the biomechanical performance of PEEK versus Ti rods using a geometrically patient-specific poroelastic finite element (FE) analyses. Ten subject-specific preoperative models were developed, and the validity of the models was evaluated with previous studies. Furthermore, FE models of those lumbar spines were regenerated based on postoperation images for posterolateral fixation at the L4–L5 level. Biomechanical responses for instrumented and adjacent intervertebral discs (IVDs) were analyzed and compared subjected to static and cyclic loading. The preoperative model results were well comparable with previous FE studies. The PEEK construct demonstrated a slightly increased range of motion (ROM) at the instrumented level, but decreased ROM at adjacent levels, as compared with the Ti. However, no significant changes were detected during axial rotation. During cyclic loading, disc height loss, fluid loss, axial stress, and collagen fiber strain in the adjacent IVDs were higher for the Ti construct when compared with the intact and PEEK models. Increased ROM, experienced stress in AF, and fiber strain at adjacent levels were observed for the Ti rod group compared with the intact and PEEK rod group, which can indicate the risk of ASD for rigid fixation. Similar to the aforementioned pattern, disc height loss and fluid loss were significantly higher at adjacent levels in the Ti rod group after cycling loading which alter the fluid–solid interaction of the adjacent IVDs. This phenomenon debilitates the damping quality, which results in disc disability in absorbing stress. Such finding may suggest the advantage of using a semirigid fixation system to decrease the chance of ASD.

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Section: Introductionmentioning

confidence: 99%

Biomechanical Investigation Between Rigid and Semirigid Posterolateral Fixation During Daily Activities: Geometrically Parametric Poroelastic Finite Element Analyses

Nikkhoo

Chen

et al. 2021

Front. Bioeng. Biotechnol.

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“…Degeneration in the spine's structures can affect the stability [1][2][3][19][20]. The longitudinal rods used in xation should preserve the structural integrity of the spinal construct.…”

Section: Discussionmentioning

confidence: 99%

The influence of accessory rods and connectors on the dynamic response of spine fixation

Pekedis¹,

Altan²,

Akgül³

et al. 2021

Preprint

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Purpose This study presents a nondestructive technique to assess the influence of accessory rods and connectors on the dynamic response of spine fixation.Methods Eighteen spine specimens were divided into three construct groups such as group I (2 rods [2R]), II (2 primary rods + 2 accessory rods with 2 transverse connectors [4R+2TC]) and III (2 primary rods + 2 accessory rods with 4 transverse connectors [4R+4TC]). Anterior corpectomy was performed for all specimens. A custom test setup was built to assess the dynamic responses of constructs in flexion-extension (FE) and left-right lateral bending (LRLB) motions. This setup can slide in lateral direction, and it is excited with an electrodynamic shaker vibrated at band limited random frequencies. Accelerometer and reusable dynamic strain sensors were installed on constructs to monitor the dynamic responses. Quasi-static eccentric loading tests were performed to determine the range of motion (RoM).Results The results demonstrated that accessory rods significantly increase the resonance frequency (RF) and decrease the strain over standard 2R construction. Although 4R+4TC provided greatest reduction in rod strain over 4R+2TC and 2R, additional 2 connectors have no significant influence on dynamic response in FE motion.Conclusions An increase in the number of rods has a significant role on the improvement of the fixation's integrity in FE and LRLB motions. However, the additional transverse connectors have significant involvements only in LRLB motion. RF obtained from dynamic tests correlated with the RoM which indicates that the technique could be used as an addendum to the quasi-static test.

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“…The LIFD spring component designed in our previous study was optimized using the Taguchi method ( Fig 2 ). The number of turns of the active coils of the spring and the wire diameter of the spring were selected as design variables, and the spring stiffness was fixed at 20 kN based on our previous results [ 26 ]. The number of turns of the active coils of the spring and the wire diameter of the spring were calculated as follows: where G denotes the shear modulus, d is the wire diameter of the spring, D is the mean diameter of the spring, and N is the number of turns of the active coils of the spring.…”

Section: Methodsmentioning

confidence: 99%

“…In our previous study, we designed a lumbar interspinous fixation device (LIFD) that addressed the limitations of the ISD and performed a finite element analysis to verify the fundamental performance of the LIFD, in terms of structural and dynamical stabilities. Although the LIFD can be used for the lumbar spine with intervertebral disc diseases, only the L3-L4 lumbar segment was used in this study, and the safety of the interspinous process inserted with the LIFD was not examined by calculating the facet joint force (FJF) in all lumbar segments [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Optimization of a lumbar interspinous fixation device for the lumbar spine with degenerative disc disease

et al. 2022

Self Cite

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Interspinous spacer devices used in interspinous fixation surgery remove soft tissues in the lumbar spine, such as ligaments and muscles and may cause degenerative diseases in adjacent segments its stiffness is higher than that of the lumbar spine. Therefore, this study aimed to structurally and kinematically optimize a lumbar interspinous fixation device (LIFD) using a full lumbar finite element model that allows for minimally invasive surgery, after which the normal behavior of the lumbar spine is not affected. The proposed healthy and degenerative lumbar spine models reflect the physiological characteristics of the lumbar spine in the human body. The optimum number of spring turns and spring wire diameter in the LIFD were selected as 3 mm and 2 turns, respectively—from a dynamic range of motion (ROM) perspective rather than a structural maximum stress perspective—by applying a 7.5 N∙m extension moment and 500 N follower load to the LIFD-inserted lumbar spine model. As the spring wire diameter in the LIFD increased, the maximum stress generated in the LIFD increased, and the ROM decreased. Further, as the number of spring turns decreased, both the maximum stress and ROM of the LIFD increased. When the optimized LIFD was inserted into a degenerative lumbar spine model with a degenerative disc, the facet joint force of the L3-L4 lumbar segment was reduced by 56%–98% in extension, lateral bending, and axial rotation. These results suggest that the optimized device can strengthen the stability of the lumbar spine that has undergone interspinous fixation surgery and reduce the risk of degenerative diseases at the adjacent lumbar segments.

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Design of a Lumbar Interspinous Fixation Device for Minimally Invasive Surgery and Spine Motion Stabilization

Cited by 3 publications

References 37 publications

Biomechanical Investigation Between Rigid and Semirigid Posterolateral Fixation During Daily Activities: Geometrically Parametric Poroelastic Finite Element Analyses

Biomechanical Investigation Between Rigid and Semirigid Posterolateral Fixation During Daily Activities: Geometrically Parametric Poroelastic Finite Element Analyses

The influence of accessory rods and connectors on the dynamic response of spine fixation

Optimization of a lumbar interspinous fixation device for the lumbar spine with degenerative disc disease

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