Does lumbar microdiscectomy affect adjacent segmental disc degeneration? A finite element study

Tang, Shujie; Rebholz, Brandon J.

doi:10.1016/j.jss.2012.09.012

Cited by 27 publications

(41 citation statements)

References 13 publications

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“…4 and Table. 1), with smaller sizes (mesh re nement) being used in areas that experienced serious mesh distortion. The contact type of each surface, excluding facet cartilage, was de ned as bounded, and the cartilage-cartilage contact was de ned as frictionless [8,9,14,18,28,29]. Six degrees of freedom were rigidly xed under the inferior of L5, and moments were applied to the superior of L4 [6,12,16,21].…”

Section: Boundary and Loading Conditionsmentioning

confidence: 99%

“…Biomechanical deterioration is a key trigger for lumbar disc degenerative diseases (DDDs) [1][2][3][4][5]. Therefore, optimized nite element analysis (FEA), which is a widely used biomechanical research method, is an ideal approach for the accurate investigation of DDD pathogenesis and treatments [6][7][8][9][10][11][12][13][14][15]. A series of model validation methods have been implemented by comparing the differences in the range of motion (ROM), which is a key index for lumbar motility and stability, between the FEA results and those from widely cited in vitro studies [7,10,11,[14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…However, such methods have not been de ned consistently in previous FEA studies. For example, Tang et al modelled the centre of the nucleus as being slightly posterior to the centre of the disc, occupying 43% of the total disc volume [9]. Schmidt et al modelled the centre of the nucleus as being 3.5 mm towards the posterior side, with a nucleus size that was approximately 44% of the total disc area [20].…”

Section: Introductionmentioning

confidence: 99%

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Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Xi¹,

Zhang²,

Sun³

et al. 2020

Preprint

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Background: As a widely used biomechanical research method, finite element analysis (FEA) is an important tool for investigating the pathogenesis of disc degenerative diseases and optimizing spine surgical methods. However, the definitions of the relative nucleus position and its cross-sectional area ratio do not conform to a uniform standard, thus affecting the accuracy (ACC) of the FEA. Hence, this study aimed to determine a precise definition of the relative nucleus position and its cross-sectional area ratio to increase the ACC of the following FEA studies. Methods: The lumbar relative nucleus position and its cross-sectional area ratio were measured from magnetic resonance imaging data and then calibrated and validated via FEA. Imaging data from patients without disc degeneration were used. The L4-L5 nucleus and disc cross-sectional areas and the distances between the edges of the annulus and nucleus were measured; the ratios between these values were calculated as P1 and P2, respectively. The FEA model was constructed using these measured values, and the relative nucleus position was calibrated by estimating the differences in the range of motion (ROM) between the model, wherein the ligaments, facet joints and nucleus were suppressed, and that of an in vitro study. Then, the ACC was re-estimated in the model with all non-bony structures by comparing the ROM, the intradiscal pressure (IDP), the facet contact force (FCF) and the disc compression (DC) under different sizes and directions of moments magnitudes to validate the measured and calibrated indicators. Results: The interobserver homogeneity was acceptable, and the measured P1 and P2 values were 1.22 and 38%, respectively. Furthermore, an ACC of up to 99% was attained for the model under flexion–extension conditions when the calibrated P1 value (1.62) was used, with a model validation of greater than 90% attained under al most all of the loading conditions considering the different indicators and moment magnitude s. Conclusion: The measured and calibrated relative nucleus position and its cross-sectional area ratio increase the ACC of the FEA model and can therefore be used in subsequent studies.

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Section: Boundary and Loading Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Xi¹,

Zhang²,

Sun³

et al. 2020

Preprint

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“…The material property of the nucleus pulposus was modified as those of the annulus ground substance (14). To facilitate the study, we assumed the annulus fibrosus was kept intact in two nucleotomy models.…”

Section: The Nucleotomy Modelsmentioning

confidence: 99%

“…Nucleotomy is a common surgical procedure in the treatment of disc herniation and the space of nucleus pulposus will be replaced by granulation tissues after surgery (4,10,14), resulting in increased stiffness, decreased elasticity (1,6) and changed biomechanics at the operated level. Clinically, the disc space height decreases significantly after nucleotomy with time (5,8), and may decrease the lordosis of the lumbar spine and affect stress conduction (13), indicating aggravated degeneration of the lumbar segment.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the influence of nucleotomy on the lumbar degeneration of operated level using the finite element method

Dou¹,

Tang²

2012

Turkish Neurosurgery

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AIm:To determine whether nucleotomy may aggravate lumbar degeneration at the operated level. mATeRIAL and meTHods: A normal healthy finite element model, two degeneration models and corresponding nucleotomy models of the L4-5 segment were created. Combined with 800 N preloading, 10 Nm moment was applied on the L4 superior endplate to simulate extension, flexion, left axial rotation and lateral bending, respectively. The shear stress of annulus fibrosus, posterior annulus bulge along with the contact force of facet joint at L4-5 were investigated. ResuLTs:In all loading directions, the shear stress and contact force of the facet joint in two nucleotomy models were higher than those in mildly or moderately degenerative models, while the posterior annulus bulge was lower than those in mildly or moderately degenerative models.CoNCLusIoN: Nucleotomy may adversely aggravate lumbar degeneration at the operated level KeywoRds: Nucleotomy, Posterior annulus bulge, Contact force of facet joint, Shear stress, Finite element analysis ÖZ AmAÇ: Nükleotominin ameliyat edilen düzeyde lomber dejenerasyonu arttırıp, arttırmadığını belirlemek. yÖNTem ve GeReÇLeR: L4-5 segmenti için normal sağlıklı bir sonlu eleman modeli, iki dejenerasyon modeli ve karşılık gelen nükleotomi modelleri oluşturuldu. 800 N ön yükleme ile kombine edilerek L4 superior uç plakasına sırasıyla ekstansiyon, fleksiyon, sol aksiyal rotasyon ve lateral bükülmeyi simüle etmek üzere 10 Nm moment uygulandı. L4-5 üzerinde annulus fibrozus üzerine kırpma stresi, posterior annulus kabarması ve faset ekleminde temas gücü incelendi.BuLGuLAR: Tüm yükleme yönlerinde kırpma ve faset ekleminde temas gücü iki nükleotomi modelinde hafif veya orta derecede dejeneratif modellerden daha yüksekken posterior annulus kabarması hafif veya orta derecede dejeneratif modellerden daha düşüktü. soNuÇ: Nükleotomi, ameliyat edilen düzeyde lomber dejenerasyon üzerine olumsuz etki yapabilir ANAHTAR sÖZCÜKLeR: Nükleotomi, Posterior annulus kabarması, Faset eklemi temas gücü, Kayma gerilimi, Sonlu eleman analizi

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Lumbar disc herniation treated by microendoscopic discectomy

et al. 2018

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Does lumbar microdiscectomy affect adjacent segmental disc degeneration? A finite element study

Cited by 27 publications

References 13 publications

Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Measurement and calibration of the nucleus position and its cross-sectional area ratio to increase the accuracy of finite element analysis

Analysis of the influence of nucleotomy on the lumbar degeneration of operated level using the finite element method

Lumbar disc herniation treated by microendoscopic discectomy

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