Biomechanical evaluation of anterior lumbar interbody fusion with various fixation options: Finite element analysis of static and vibration conditions

Shen, Hangkai; Chen, Yuru; Liao, Zhenhua; Liu, Weiqiang

doi:10.1016/j.clinbiomech.2021.105339

Cited by 13 publications

(6 citation statements)

References 32 publications

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“…This region might reinforce the fusion mass formation in the anterior column promoting lumbar interbody fusion, preventing graft subsidence, and maintaining achieved indirect decompression/lordosis. 25,26 Additionally, selective anodization with a gradient linear pattern focused on the osteogenic electrical fields within the pedicles may strengthen the screw purchase, potentially preventing implant loosening and pull out. 27,28 Directional/spatial guidance of the direct current electrical stimulation is expected to translate to a safer and more effective therapy.…”

Section: Discussionmentioning

confidence: 99%

Electroactive Spinal Instrumentation for Targeted Osteogenesis and Spine Fusion: A Computational Study

Javeed¹,

Zhang²,

Greenberg³

et al. 2023

Int J Spine Surg

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Background: Direct current electrical stimulation may serve as a promising nonpharmacological adjunct promoting osteogenesis and fusion. The aim of this study was to evaluate the utility of electroactive spine instrumentation in the focal delivery of therapeutic electrical stimulation to enhance lumbar bone formation and interbody fusion.Methods: A finite element model of adult human lumbar spine (L4-L5) instrumented with single-level electroactive pedicle screws was simulated. Direct current electrical stimulation was routed through anodized electroactive pedicle screws to target regions of fusion. The electrical fields generated by electroactive pedicle screws were evaluated in various tissue compartments including isotropic tissue volumes, cortical, and trabecular bone. Electrical field distributions at various stimulation amplitudes (20-100 µA) and pedicle screw anodization patterns were analyzed in target regions of fusion (eg, intervertebral disc space, vertebral body, and pedicles).Results: Electrical stimulation with electroactive pedicle screws at various stimulation amplitudes and anodization patterns enabled modulation of spatial distribution and intensity of electric fields within the target regions of lumbar spine. Anodized screws (50%) vs unanodized screws (0%) induced high-amplitude electric fields within the intervertebral disc space and vertebral body but negligible electric fields in spinal canal. Direct current electrical stimulation via anodized screws induced electrical fields, at therapeutic threshold of >1 mV/cm, sufficient for osteoinduction within the target interbody region.Conclusions: Selective anodization of electroactive pedicle screws may enable focal delivery of therapeutic electrical stimulation in the target regions in human lumbar spine. This study warrants preclinical and clinical testing of integrated electroactive system in inducing target lumbar fusion in vivo.Clinical Relevance: The findings of this study provide a foundation for clinically investigating electroactive intrumentation to enhance spine fusion.

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Section: Discussionmentioning

confidence: 99%

Electroactive Spinal Instrumentation for Targeted Osteogenesis and Spine Fusion: A Computational Study

Javeed¹,

Zhang²,

Greenberg³

et al. 2023

Int J Spine Surg

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“…From the results, this model vividly simulates the structure of the human lumbar spine bone and soft tissue and accurately simulates the stress of the involved lumbar spine under different working conditions. [28][29][30] Under different motion states, the range of motion of the 2 new lumbar models is significantly smaller than that of the normal model, indicating that the screw rod internal fixation system plays a significant role in limiting the range of motion of the vertebral body and that the screw rod internal fixation can effectively maintain the stability of the spine. Comparing the stress changes of the model before and after internal fixation, it can be seen that the nail rod internal fixation system makes the stress transfer of the lumbar spine concentrated on the nail body and reduces the stress load of the lumbar spine's structure, such as the endplate, intervertebral disc, and pedicle, which shows that it can effectively prevent the premature degradation of lumbar-related structures.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical characteristics of 2 different posterior fixation methods of bilateral pedicle screws: A finite element analysis

Zhang

Song

et al. 2022

Medicine

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Background: To explore the biomechanical characteristics of 2 posterior bilateral pedicle screw fixation methods using finite element analysis.Methods: A normal L3-5 finite element model was established. Based on the verification of its effectiveness, 2 different posterior internal fixation methods were simulated: bilateral pedicle screws (model A) were placed in the L3 and L5 vertebral bodies, and bilateral pedicle screws (model B) were placed in the L3, L4, and L5 vertebral bodies. The stability and stress differences of intervertebral discs, endplates, screws, and rods between models were compared.Results: Compared with the normal model, the maximum stress of the range of motion, intervertebral disc, and endplate of the 2 models decreased significantly. Under the 6 working conditions, the 2 internal fixation methods have similar effects on the stress of the endplate and intervertebral disc, but the maximum stress of the screws and rods of model B is smaller than that of model A.Conclusions: Based on these results, it was found that bilateral pedicle screw fixation in 2 vertebrae L3 and L5 can achieve similar stability as bilateral pedicle screw fixation in 3 vertebrae L3, L4, and L5. However, the maximum stress of the screw and rod in model B is less than that in model A, so this internal fixation method can effectively reduce the risk of fracture. The 3-dimensional finite element model established in this study is in line with the biomechanical characteristics of the spine and can be used for further studies on spinal column biomechanics. This information can serve as a reference for clinicians for surgical selection.

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“…Also, the results showed that the DIAM model produced higher ROM at implanted level but lower ROM at adjacent levels than the Bioflex model, especially under the lateral bending and axial rotation (Figure 3). This might be because proximity of the DIAM to the rotation axis for lateral bending and axial rotation limited its resistance to these two moments at implanted level 36,37 . It implies that compared with Bioflex, the DIAM could better preserve mobility of the implanted level and might lessen the probability of ASD.…”

Section: Discussionmentioning

confidence: 99%

“…This might be because proximity of the DIAM to the rotation axis for lateral bending and axial rotation limited its resistance to these two moments at implanted level. 36,37 It implies that compared with Bioflex, the DIAM could better preserve mobility of the implanted level and might lessen the probability of ASD. This finding is comparable with the clinical results from a meta-analysis of chou et al 38 who reported that regarding the incidence of radiographic ASD, there were 1% and 10.5% in IPS and PSDS groups, respectively.…”

Section: Discussionmentioning

confidence: 99%

Biomechanical analysis of lumbar nonfusion dynamic stabilization using a pedicle screw‐based dynamic stabilizer or an interspinous process spacer

Fan

Zhang

et al. 2022

Numer Methods Biomed Eng

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This study aimed to investigate and compare the effects of two widely used nonfusion posterior dynamic stabilization (NPDS) devices, pedicle screw-based dynamic stabilizer (PSDS) and interspinous process spacer (IPS), on biomechanics of the implanted lumbar spine under static and vibration loadings.The finite element model of healthy human lumbosacral segment was modified to incorporate NPDS device insertion at L4-L5 segment. Bioflex and DIAM were used as PSDS-based and IPS-based NPDS devices, respectively. As a comparison, lumbar interbody fusion with rigid stabilization was also simulated at L4-L5. For static loading, segmental range of motion (ROM) of the models under moments of four physiological motions was computed using hybrid testing protocol. For vibration loading, resonant modes and dynamic stress of the models under vertical excitation were extracted through random response analysis. The results showed that compared with the rigid fusion model, ROM of the nonfusion models was higher at L4-L5 level but lower at adjacent levels (L1-L2, L2-L3, L3-L4, L5-S1). Compared with the Bioflex model, the DIAM model produced higher ROM at L4-L5 level but lower ROM at adjacent levels, especially under lateral bending and axial rotation; resonant frequency of the DIAM model was slightly lower; dynamic response of nucleus stress at L4-L5 level was slightly higher for the DIAM model, and the dynamic stress at adjacent levels was no obvious difference between the nonfusion models. This study reveals biomechanical differences between the Bioflex and DIAM systems, which may provide references for selecting surgical approaches in clinical practice.

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Biomechanical evaluation of anterior lumbar interbody fusion with various fixation options: Finite element analysis of static and vibration conditions

Cited by 13 publications

References 32 publications

Electroactive Spinal Instrumentation for Targeted Osteogenesis and Spine Fusion: A Computational Study

Electroactive Spinal Instrumentation for Targeted Osteogenesis and Spine Fusion: A Computational Study

Biomechanical characteristics of 2 different posterior fixation methods of bilateral pedicle screws: A finite element analysis

Biomechanical analysis of lumbar nonfusion dynamic stabilization using a pedicle screw‐based dynamic stabilizer or an interspinous process spacer

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