Biomechanics of Artificial Disc Replacements Adjacent to a 2-Level Fusion in 4-Level Hybrid Constructs: An In Vitro Investigation

Liao, Zhenhua; Fogel, Guy R.; Gu, Hongsheng; Liu, Weiqiang

doi:10.12659/msm.896274

Cited by 7 publications

(4 citation statements)

References 29 publications

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“…Briefly, the original form of this protocol consisted of (a) applying pure moments to intact spine, (b) applying pure moments to implanted spine until its ROM is equal to the ROM of the intact spine (i.e., results from the previous step), and (c) the statistical comparison of the biomechanical variables in the two conditions. This motion-controlled moment loading was selected to simulate the clinical setting related to the total motion of the cervical spine [30][31][32][33]. A force of 73.6 N was applied to the upper surface of the C2 vertebral body, 1.5 N/M was applied in the X-axis direction according to the right-hand rule, and a moment of 1.0 N/M was applied to the Y-axis and Z-axis to simulate the flexion, extension, left/right lateral bending, and left/right axial rotation of the cervical spine.…”

Section: Finite Element Analysis (Fea) Model Establishmentmentioning

confidence: 99%

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

Sun

Wang

Cai

et al. 2021

BMC Musculoskelet Disord

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Background In current clinical practice, the most commonly used fusion cage materials are titanium (Ti) alloys. However, titanium alloys are non-degradable and may cause stress shielding. ZK60 is a bio-absorbable implant that can effectively avoid long-term complications, such as stress shielding effects, implant displacement, and foreign body reactions. In this study, we aimed at investigating the biomechanical behavior of the cervical spine after implanting different interbody fusion cages. Methods The finite element (FE) models of anterior cervical disc removal and bone graft fusion (ACDF) with a ZK60 cage and a Ti cage were constructed, respectively. Simulations were performed to evaluate their properties of flexion, extension, lateral bending, and axial rotation of the cervical spine. Moreover, a side-by-side comparison was conducted on the range of motion (ROM), the deformation of cages, the stress in the cages, bone grafts, and cage-end plate interface. Simultaneously, according to the biomechanical analysis results, the microporous structure of the ZK60 cage was improved by the lattice topology optimization technology and validation using static structure. Results The ROMs in the current study were comparable with the results reported in the literature. There was no significant difference in the deformation of the two cages under various conditions. Moreover, the maximum stress occurred at the rear of the cage in all cases. The cage’s and endplate-cage interface’s stress of the ZK60 group was reduced compared with the Ti cage, while the bone graft stress in the ZK60 fusion cage was significantly greater than that in the Ti fusion cage (average 27.70%). We further optimized the cage by filling it with lattice structures, the volume was decreased by 40%, and validation showed more significant biomechanical properties than ZK60 and Ti cages. Conclusion The application of the ZK60 cage can significantly increase the stress stimulation to the bone graft by reducing the stress shielding effect between the two instrumented bodies. We also observed that the stress of the endplate-cage interface decreased as the reduction of the cage’s stiffness, indicating that subsidence is less likely to occur in the cage with lower stiffness. Moreover, we successfully designed a porous cage based on the biomechanical load by lattice optimization.

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Section: Finite Element Analysis (Fea) Model Establishmentmentioning

confidence: 99%

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

Sun

Wang

Cai

et al. 2021

BMC Musculoskelet Disord

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“…Then, we determined the bending moment in both modes to each CDA spine that matched the ROM determined in the pure moment condition for the intact spine. In other words, the hybrid moment protocol was followed in the present study, a protocol also used in other studies [18][19][20][21]. While CDAs are used in the military, impact loads should be studied because the population is subjected to activities involving higher g-forces, routinely [22,23].…”

Section: Loading and Output Parametersmentioning

confidence: 99%

A Comparison Study of Four Cervical Disk Arthroplasty Devices Using Finite Element Models

et al. 2021

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Study Design: The study examined and compared four artificial cervical disks using validated finite element models.Purpose: To compare and contrast the biomechanical behavior of four artificial cervical disks by determining the external (range of motion) and internal (facet force and intradiscal pressure) responses following cervical disc arthroplasty (CDA) and to elucidate any device design effects on cervical biomechanics.Overview of Literature: Despite CDA’s increasing popularity most studies compare the CDA procedure with anterior cervical discectomy and fusion. There is little comparative evaluation of different artificial disks and, therefore, little understanding of how varying disk designs may influence spinal biomechanics.Methods: A validated C2–T1 finite element model was subjected to flexion-extension. CDAs were simulated at the C5–C6 level with the Secure-C, Mobi-C, Prestige LP, and Prodisc C prosthetic disks. We used a hybrid loading protocol to apply sagittal moments. Normalized motions at the index and adjacent levels, and intradiscal pressures and facet column loads were also obtained.Results: The ranges of motion at the index level increased after CDA. The Mobi-C prosthesis demonstrated the highest amount of flexion, followed by the Secure-C, Prestige LP, and Prodisc C. The Secure-C demonstrated the highest amount of extension, followed by the Mobi-C, Prodisc C, and Prestige LP. The motion decreased at the rostral and caudal adjacent levels. Facet forces increased at the index level and decreased at the rostral and caudal adjacent levels following CDA. Intradiscal pressures decreased at the adjacent levels for the Mobi-C, Secure-C, and Prodisc C. Conversely, the use of the Prestige LP increased intradiscal pressure at both adjacent levels.Conclusions: While all artificial disks were useful in restoring the index level motion, the Secure-C and Mobi-C translating abilities allowed for lower intradiscal pressures at the adjacent segments and may be the driving mechanism for minimizing adjacent segment degenerative arthritic changes. The facet joint integrity should also be considered in the clinical decision-making process for CDA selection.

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“…The decompression of the spinal cord and nerve roots usually requires the removal of some structures that maintain spinal stability, such as the lamina and facet process, which changes the biomechanics of the adjacent segments. Previous research has shown that the fusion and fixation of the moving segments increases the stress of the adjacent segments at the cephalic side [ 27 ]. Smith Robinson et al conducted finite element analysis after spinal fusion surgery, which also showed that the internal stress of the cephalic segment increased [ 28 ].…”

Section: Discussionmentioning

confidence: 99%

Comparison of the clinical effects of lamina replantation and screw fixation after laminectomy in the treatment of intraspinal tumours

Liu,

Zheng,

Yuan

et al. 2023

J Orthop Surg Res

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Introduction Intraspinal tumours are common diseases in neurosurgery and spinal surgery. Due to the fact that most of them are benign tumours, surgical resection is usually effective, and it is also the main treatment for these tumours. To maintain the stability of the spine and to reduce the incidence of kyphosis, pedicle screw fixation is required after traditional laminectomy, but there are many complications. In recent years, tumour resection and laminectomy have become increasingly favoured by clinicians. However, the comparison of the clinical effects of lamina complex replantation and pedicle screw fixation after laminectomy in the treatment of intraspinal tumours is still unknown. This paper systematically compared the two methods from many aspects and discussed their advantages and disadvantages to obtain better clinical guidance. Materials and methods In this study, a retrospective analysis was conducted to select 58 patients who underwent posterior approach tumour resection in the spinal surgery department of our hospital from January 2017 to January 2020. Among them, 32 patients underwent tumour resection and laminoplasty, and 26 patients underwent tumour resection and screw internal fixation. The age, sex, body mass index (BMI), smoking status, duration of symptoms, operation time, length of hospital stay, postoperative complications, amount of bleeding and other data were summarized, calculated and compared. Results 1. The age, sex, BMI, smoking status and symptom duration of the two groups were compared. The abovementioned results were not statistically significant. 2. The operation time, hospital stay, postoperative complications, intraoperative bleeding and adjacent segment degeneration (ASD) were counted and compared between the two groups. There was no significant difference in hospital stay or intraoperative bleeding between the two groups; in addition, the operation time, postoperative complications and incidence of ASD were statistically significant. 3. The visual analog scale (VAS) score, Oswestry Disability Index (ODI) score of thoracic and lumbar spines and Neck Disability Index (NDI) score of cervical spine patients in the two groups were counted, and the preoperative and postoperative data, as well as their changes, were counted and compared between groups and within groups. There was no statistical significance between the two groups; moreover, the postoperative scores were all significantly lower than preoperative in the group. 4. According to the spinal cord function ASIA grade, the preoperative, final follow-up and change values of the two groups were counted, and intragroup and intergroup comparisons were made. There was no significant difference between the two groups; in addition, the scores of the final follow-up were significantly higher than preoperative in the group. 5. The spinal mobility was measured and recorded before the operation and at the final follow-up. There was no significant difference between preoperative and postoperative cervical mobility, and there was no statistical significance observed; furthermore, the range of flexion, extension, rotation and lateral bending of the thoracic and lumbar spines in the screw fixation group was significantly lower than that in the lamina replantation group. Conclusions Lamina replantation can be used as splendid methods for the treatment of Intraspinal tumour. Lamina replantation can reduce the operation time, as well as reduce the occurrence of postoperative cerebrospinal fluid leakage, iatrogenic spinal stenosis, posterior soft tissue adhesion and ASD. These complications are reduced in comparison to the other mode of management and better preserve the mobility of the spine.

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Biomechanics of Artificial Disc Replacements Adjacent to a 2-Level Fusion in 4-Level Hybrid Constructs: An In Vitro Investigation

Cited by 7 publications

References 29 publications

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

A Comparison Study of Four Cervical Disk Arthroplasty Devices Using Finite Element Models

Comparison of the clinical effects of lamina replantation and screw fixation after laminectomy in the treatment of intraspinal tumours

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