Analysis of biomechanical changes after removal of instrumentation in lumbar arthrodesis by finite element analysis

Kim, Ho-Joong; Chun, Hye‐Yeong; Moon, Seong Hwan; Kang, Kyoung‐Tak; Kim, Hak-Sun; Park, Jin Oh; Moon, Eun Su; Sohn, Joon Seok; Lee, Hwan Mo

doi:10.1007/s11517-010-0621-2

Cited by 47 publications

(45 citation statements)

References 31 publications

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“…A pure moment of 10 Nm combined with a pre-compressive load of 150 N [19], [21]–[23] was applied to the top surface of T9. Flexion, extension, left/right lateral bending, and left/right axial rotation were simulated.…”

Section: Methodsmentioning

confidence: 99%

Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

Zhou

Wang

et al. 2014

PLoS ONE

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ObjectiveTo compare the von Mises stresses of the internal fixation devices among different short segment pedicle screw fixation techniques to treat thoracic 12 vertebral fractures, especially the mono-segment pedicle screw fixation and intermediate unilateral pedicle screw fixation techniques.MethodsFinite element methods were utilised to investigate the biomechanical comparison of the four posterior short segment pedicle screw fixation techniques (S4+2: traditional short-segment 4 pedicle screw fixation [SPSF]; M4+2: mono-segment pedicle screw fixation; I6+2: intermediate bilateral pedicle screw fixation; and I5+2: intermediate unilateral pedicle screw fixation).ResultsThe range of motion (ROM) in flexion, axial rotation, and lateral bending was the smallest in the I6+2 fixation model, followed by the I5+2 and S4+2 fixation models, but lateral bending was the largest in the M4+2 fixation model. The maximal stress of the upper pedicle screw is larger than the lower pedicle screw in S4+2 and M4+2. The largest maximal von Mises stress was observed in the upper pedicle screw in the S4+2 and M4+2 fixation models and in the lower pedicle screw in the I6+2 and I5+2 fixation models. The values of the largest maximal von Mises stress of the pedicle screws and rods during all states of motion were 263.1 MPa and 304.5 MPa in the S4+2 fixation model, 291.6 MPa and 340.5 MPa in the M4+2 fixation model, 182.9 MPa and 263.2 MPa in the I6+2 fixation model, and 269.3 MPa and 383.7 MPa in the I5+2 fixation model, respectively. Comparing the stress between different spinal loadings, the maximal von Mises stress of the implants were observed in flexion in all implanted models.ConclusionAdditional bilateral pedicle screws at the level of the fracture to SPSF may result in a stiffer construct and less von Mises stress for pedicle screws and rods. The largest maximal von Mises stress of the pedicle screws during all states of motion were observed in the mono-segment pedicle screw fixation technique.

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Section: Methodsmentioning

confidence: 99%

Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

Zhou

Wang

et al. 2014

PLoS ONE

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“…However, even though many previous studies have reported excellent surgical results with instrumented lumbar fusion for degenerative lumbar disease,1,3,4 the robust stiffness of pedicle screws and rods might lead to an increase in the stress concentration at the adjacent segment after fusion, which could be a candidate risk factor for adjacent segment degeneration (ASD) 5,6,7,8…”

Section: Introductionmentioning

confidence: 99%

“…Unilateral instrumentation has advantages over bilateral fixation in terms of reduced operation time, medical expenses, blood loss, and hospital stay duration 10,11. Furthermore, unilateral pedicle screw fixation can lead to a decrease in fusion segment stiffness and stress of facet joint at superior adjacent segment 5,16. From this perspective, unilateral pedicle screw fixation would have a positive effect on stress concentration at the adjacent segment after lumbar fusion surgery, which seems to be a potential benefit of unilateral fixation.…”

Section: Introductionmentioning

confidence: 99%

Biomechanical Analysis of Fusion Segment Rigidity Upon Stress at Both the Fusion and Adjacent Segments: A Comparison between Unilateral and Bilateral Pedicle Screw Fixation

et al. 2014

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PurposeThe purpose of this study was to investigate the effects of unilateral pedicle screw fixation on the fusion segment and the superior adjacent segment after one segment lumbar fusion using validated finite element models.Materials and MethodsFour L3-4 fusion models were simulated according to the extent of decompression and the method of pedicle screws fixation in L3-4 lumbar fusion. These models included hemi-laminectomy with bilateral pedicle screw fixation in the L3-4 segment (BF-HL model), total laminectomy with bilateral pedicle screw fixation (BF-TL model), hemi-laminectomy with unilateral pedicle screw fixation (UF-HL model), and total laminectomy with unilateral pedicle screw fixation (UF-TL model). In each scenario, intradiscal pressures, annulus stress, and range of motion at the L2-3 and L3-4 segments were analyzed under flexion, extension, lateral bending, and torsional moments.ResultsUnder four pure moments, the unilateral fixation leads to a reduction in increment of range of motion at the adjacent segment, but larger motions were noted at the fusion segment (L3-4) in the unilateral fixation (UF-HL and UF-TL) models when compared to bilateral fixation. The maximal von Mises stress showed similar patterns to range of motion at both superior adjacent L2-3 segments and fusion segment.ConclusionThe current study suggests that unilateral pedicle screw fixation seems to be unable to afford sufficient biomechanical stability in case of bilateral total laminectomy. Conversely, in the case of hemi-laminectomy, unilateral fixation could be an alternative option, which also has potential benefit to reduce the stress of the adjacent segment.

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“…Durchgeführt wurden diese im Mittel nach 10 (6-13) Monaten, bei 25% (0-100%) in einer minimal-invasiven Technik. Eine aktuelle Finite-Elemente-Analyse konnte zeigen, dass eine Entfernung der Instrumentierung die Steifigkeit eines fusionierten Segments verringert und so den Stress auf die benachbarten Bandscheiben vermindert [25].…”

Section: Implantatentfernung Nach Instrumentierungen An Der Wirbelsäuleunclassified

Ist eine routinemäßige Implantatentfernung nach unfallchirurgischen Eingriffen sinnvoll?

et al. 2012

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Analysis of biomechanical changes after removal of instrumentation in lumbar arthrodesis by finite element analysis

Cited by 47 publications

References 31 publications

Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

Treatment of Unstable Thoracolumbar Fractures through Short Segment Pedicle Screw Fixation Techniques Using Pedicle Fixation at the Level of the Fracture: A Finite Element Analysis

Biomechanical Analysis of Fusion Segment Rigidity Upon Stress at Both the Fusion and Adjacent Segments: A Comparison between Unilateral and Bilateral Pedicle Screw Fixation

Ist eine routinemäßige Implantatentfernung nach unfallchirurgischen Eingriffen sinnvoll?

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