Finite element analysis of posterior cervical fixation

Duan, Yang; Wang, H.H.; Jin, Anmin; Zhang, L.; Min, Shaoxiong; Liu, C.L.; Qiu, Sujun; Shu, Xiang

doi:10.1016/j.otsr.2014.11.007

Cited by 19 publications

(12 citation statements)

References 24 publications

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“…Pedicle screw insertion also induces residual stresses and stress concentrations that superimpose with cyclic loads to contribute to local tissue failure. These stresses are highest at the cap‐rod‐screw interface, as we demonstrate using beams‐on‐elastic‐foundation and thick‐wall pressure vessel theory. Reported yield stresses for spinal trabecular bone range from 3 to 96 MPa .…”

Section: Discussionsupporting

confidence: 58%

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

Pearson

Dobbs

Grantham

et al. 2017

Journal Orthopaedic Research

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Section: Discussionsupporting

confidence: 58%

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

Pearson

Dobbs

Grantham

et al. 2017

Journal Orthopaedic Research

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“…Pedicle screw insertion also induces residual stresses and stress concentrations that superimpose with cyclic loads to contribute to local tissue failure. These stresses are highest at the cap-rod-screw interface, 47,48 as we demonstrate using beams-on-elastic-foundation and thick-wall pressure vessel theory. Reported yield stresses for spinal trabecular bone range from 3 to 96 MPa 49,50 .…”

Section: Discussionsupporting

confidence: 50%

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

Pearson

Dobbs²,

Grantham³

et al. 2016

Preprint

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Pedicle screw loosening has been implicated in recurrent back pain after lumbar spinal fusion, but the degree of loosening has not been systematically quantified in patients. Instrumentation removal is an option for patients with successful arthrodesis, but remains controversial. Here, we quantified pedicle screw loosening by measuring screw insertion and/or removal torque at high statistical power (β = 0.98) in N = 108 patients who experienced pain recurrence despite successful fusion after posterior instrumented lumbar fusion with anterior lumbar interbody fusion (L2-S1). Between implantation and removal, pedicle screw torque was reduced by 58%, indicating significant loosening over time. Loosening was greater in screws with evoked EMG threshold under 11 mA, indicative of screw misplacement. A theoretical stress analysis revealed increased local stresses at the screw interface in pedicles with decreased difference in pedicle thickness and screw diameter. Loosening was greatest in vertebrae at the extremities of the fused segments, but was significantly lower in segments with one level of fusion than in those with two or more. Clinical significance: These data indicate that pedicle screws can loosen significantly in patients with recurrent back pain and warrant further research into methods to reduce the incidence of screw loosening and to understand the risks and potential benefits of instrumentation removal.

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“…In previous studies, posterior cervical fixation techniques have been developed, compared and validated in the long-term clinical relevant setting and biomechanical tests: (1) LS fixation technique: Heller et al [ 33 ] suggested that the LS technique reconstructed the stability of the middle and posterior column of the lower cervical spine by penetrating the bilayer cortex with greater pullout strength than the monolayer cortex. What’s more, screw inserted by LS technique had high stress concentration at the actual caprod-screw interface, but less than 100 MPa of von Mises stress [ 34 ]. The LS fixation constrained motion in flexion as a tension band and limits motion in extension to some extend due to rigidity of rods, instead of constraining the motion in axial rotation like most pedicle screw fixations [ 35 ].…”

Section: Discussionmentioning

confidence: 99%

“…The technique is based on the pedicle insertion screw with good three-column holding power. In addition, the ROM of the model after the reconstruction of three-column damage was significantly reduced, that is, the stability was significantly increased [ 34 ]. (3) TS fixation technique: TS technique has been used as an alternative technique to achieve posterior cervical spine stability in the lower cervical spine [ 30 ].…”

Section: Discussionmentioning

confidence: 99%

A biomechanical analysis of anterior cervical discectomy and fusion alone or combined cervical fixations in treating compression-extension injury with unilateral facet joint fracture: a finite element study

Jin

Wang

Liu

et al. 2021

BMC Musculoskelet Disord

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Background Compression-extension injury with unilateral facet joint fracture is one of the most devastating injuries of subaxial cervical spine. However, it is not yet clear which fixation technique represents the optimal choice in surgical management. This study aims to assess the construct stability at the operative level (C4/C5 cervical spine) following anterior cervical discectomy and fusion (ACDF) alone and combined fixation techniques (posterior-anterior fixations). Methods A previously validated three-dimensional C2-T1 finite element model were modified to simulate surgical procedures via the anterior-only approach (ACDF) and combined cervical approach [(transarticular screw, lateral mass screw, unilateral pedicle screw, bilateral pedicle screw) + ACDF, respectively] for treating compression-extension injury with unilateral facet joint fracture at C4/C5 level. Construct stability (range of rotation, axial compression displacement and anterior shear displacement) at the operative level was comparatively analyzed. Results In comparison with combined fixation techniques, a wider range of motion and a higher maximum von Mises stress was found in single ACDF. There was no obvious difference in range of motion among transarticular screw and other posterior fixations in the presence of anterior fixation. In addition, the screws inserted by transarticular screw technique had high stress concentration at the middle part of the screw but much less than 500 MPa under different conditions. Furthermore, the variability of von Mises stress in the transarticular screw fixation device was significantly lower than ACDF but no obvious difference compared with other posterior fixations. Conclusions Of the five fixation techniques, ACDF has proven poor stability and high structural stress. Compared with lateral and pedicle screw, transarticular screw technique was not worse biomechanically and less technically demanding to acquire in clinical practice. Therefore, our study suggested that combined fixation technique (transarticular screw + ACDF) would be a reasonable treatment option to acquire an immediate stabilization in the management of compression-extension injury with unilateral facet joint fracture. However, clinical aspects must also be regarded when choosing a reconstruction method for a specific patient.

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Finite element analysis of posterior cervical fixation

Cited by 19 publications

References 24 publications

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

Intraoperative biomechanics of lumbar pedicle screw loosening following successful arthrodesis

A biomechanical analysis of anterior cervical discectomy and fusion alone or combined cervical fixations in treating compression-extension injury with unilateral facet joint fracture: a finite element study

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