scholarly journals Biomechanical Evaluation of the Lumbar Spine by Using a New Interspinous Process Device: A Finite Element Analysis

2021 ◽  
Vol 11 (21) ◽  
pp. 10486
Author(s):  
Hung-Wen Wei ◽  
Shao-Ming Chuang ◽  
Chen-Sheng Chen
Keyword(s):  
Lumbar Spine ◽  
Facet Joint ◽  
Spinal Stability ◽  
Lateral Bending ◽  
Joint Contact Force ◽  
Adjacent Disc ◽  
Joint Contact ◽  
A Minor ◽  
Interspinous Process Device ◽  
Flexion And Extension

Minimally invasive decompression is generally employed for treating lumbar spinal stenosis; however, it results in weakened spinal stability. To augment spinal stability, a new interspinous process device (NIPD) was developed in this study. The biomechanical features of the NIPD were evaluated in this study. Three finite-element (FE) models of the entire lumbar spine were implemented to perform biomechanical analysis: the intact, defect (DEF), and NIPD models. The DEF model was considered for lumbar spines with bilateral laminotomies and partial discectomy at L3–L4. Range of motion (ROM), disc stress, and facet joint contact force were evaluated in flexion, extension, torsion, and lateral bending in the three FE models. The results indicated that ROM in the extension increased by 23% in the DEF model but decreased by 23% in the NIPD model. In the NIPD model, the cephalic adjacent disc stress in flexion and extension was within 5%, and negligible changes were noted in the facet joint contact force for torsion and lateral bending. Thus, the NIPD offers superior spinal stability and causes only a minor change in cephalic adjacent disc stress in flexion and extension during the bilateral laminotomy and partial discectomy of the lumbar spine. However, the NIPD has a minor influence on the ROM and facet joint force for lateral bending and torsion.

Can extra-articular strains be used to measure facet contact forces in the lumbar spine? An in-vitro biomechanical study

2008 ◽  
Vol 222 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Q A Zhu ◽  
Y B Park ◽  
S G Sjovold ◽  
C A Niosi ◽  
D C Wilson ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Facet Joint ◽  
Axial Rotation ◽  
Contact Forces ◽  
Facet Joints ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Joint Contact ◽  
Strain Coupling ◽  
Accuracy And Repeatability

Experimental measurement of the load-bearing patterns of the facet joints in the lumbar spine remains a challenge, thereby limiting the assessment of facet joint function under various surgical conditions and the validation of computational models. The extra-articular strain (EAS) technique, a non-invasive measurement of the contact load, has been used for unilateral facet joints but does not incorporate strain coupling, i.e. ipsilateral EASs due to forces on the contralateral facet joint. The objectives of the present study were to establish a bilateral model for facet contact force measurement using the EAS technique and to determine its effectiveness in measuring these facet joint contact forces during three-dimensional flexibility tests in the lumbar spine. Specific goals were to assess the accuracy and repeatability of the technique and to assess the effect of soft-tissue artefacts. In the accuracy and repeatability tests, ten uniaxial strain gauges were bonded to the external surface of the inferior facets of L3 of ten fresh lumbar spine specimens. Two pressure-sensitive sensors (Tekscan) were inserted into the joints after the capsules were cut. Facet contact forces were measured with the EAS and Tekscan techniques for each specimen in flexion, extension, axial rotation, and lateral bending under a ±7.5 N m pure moment. Four of the ten specimens were tested five times in axial rotation and extension for repeatability. These same specimens were disarticulated and known forces were applied across the facet joint using a manual probe (direct accuracy) and a materials-testing system (disarticulated accuracy). In soft-tissue artefact tests, a separate set of six lumbar spine specimens was used to document the virtual facet joint contact forces during a flexibility test following removal of the superior facet processes. Linear strain coupling was observed in all specimens. The average peak facet joint contact forces during flexibility testing was greatest in axial rotation (71±25 N), followed by extension (27±35 N) and lateral bending (25±28 N), and they were most repeatable in axial rotation (coefficient of variation, 5 per cent). The EAS accuracy was about 20 per cent in the direct accuracy assessment and about 30 per cent in the disarticulated accuracy test. The latter was very similar to the Tekscan accuracy in the same test. Virtual facet loads (r.m.s.) were small in axial rotation (12 N) and lateral bending (20 N), but relatively large in flexion (34 N) and extension (35 N). The results suggested that the bilateral EAS model could be used to determine the facet joint contact forces in axial rotation but may result in considerable error in flexion, extension, and lateral bending.

scholarly journals Finite Element Analysis of Stability of Internal Fixation Reconstruction Methods for Lumbar Total Vertebral Resection

2020 ◽  
Author(s):  
Shengcheng Wan ◽  
Zhaoyi Wu ◽  
Yuanwu Cao ◽  
Xiaoxing Jiang ◽  
Zixian Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Internal Fixation ◽  
Vertebral Body ◽  
Spinal Stability ◽  
Lateral Bending ◽  
Short Segment ◽  
Short Segment Fixation ◽  
Anterior Support ◽  
Artificial Vertebral Body

Abstract Objective To compare the effect of different fixation methods on spinal stability after total en bloc spondylectomy(TES) of lumbar spine.Method The finite element models were established based on the CT scan of a healthy volunteer. After the validity of the models was confirmed, the models with different posterior fixation methods of the lumbar spine were established with and without the artificial vertebral body, respectively. The motions of flexion, extension, lateral bending and rotation under supine and standing conditions were simulated. The angular displacement of T11-L3 and stress of internal fixations were compared and analyzed.Results The finite element models of spinal reconstruction after TES were obtained. When the anterior support existed, the movement of the spine after TES was not affected by the gravity of the upper body. The movements in the opposite direction on the same plane were similar. All three methods provided enough stability to the spine. The improved short-segment fixation shared stress of the artificial vertebral body with no obvious negative effect. The long-segment fixation had stronger fixation effect with the huge loss of the range of motion of lumbar spine. When the anterior support failed, obvious rotation showed in lateral bending in all models. The short-segment fixation and the long-segment fixation failed to maintain the spinal stability with fixations breakage or functional loss. The improved short-segment fixations showed strong ability in maintaining the spinal stability. The vertebral body screws can prevent the failure of anterior fixation by sharing great stress of the whole internal fixation system. The improved short-segment had huge advantages over the others.Conclusion After TES, the improved short-segment fixation can provide more stability to the spine. The vertebral body screws can prevent the failure of the internal fixation by reducing the stress of the anterior support. This fixation method should be promoted in clinical practice while the effect requires more observation.

ProDisc Cervical Arthroplasty Does Not Alter Facet Joint Contact Pressure During Lateral Bending or Axial Torsion

Spine ◽  
2013 ◽  
Vol 38 (2) ◽  
pp. E84-E93 ◽  
Author(s):  
Nicolas V. Jaumard ◽  
Joel A. Bauman ◽  
Benjamin B. Guarino ◽  
Akhilesh J. Gokhale ◽  
Daniel E. Lipschutz ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Facet Joint ◽  
Lateral Bending ◽  
Cervical Arthroplasty ◽  
Axial Torsion ◽  
Joint Contact ◽  
Joint Contact Pressure

Effect of position and height of a mobile core type artificial disc on the biomechanical behaviour of the lumbar spine

2008 ◽  
Vol 222 (2) ◽  
pp. 229-239 ◽  
Author(s):  
A Rohlmann ◽  
T Zander ◽  
B Bock ◽  
G Bergmann
Keyword(s):  
Lumbar Spine ◽  
Facet Joint ◽  
Axial Rotation ◽  
Intradiscal Pressure ◽  
Upper Body ◽  
Artificial Disc ◽  
Lateral Bending ◽  
Implant Position ◽  
Joint Force ◽  
Flexion Extension

The extent of natural disc removal and the implant position and height of an artificial disc with a mobile core were studied for their effects on intersegmental rotation, intradiscal pressure, and facet joint force. A validated finite element model of the lumbar spine was used. The model was loaded with the upper body weight, a follower load, and muscle forces to simulate standing, flexion, extension, lateral bending, and axial rotation. The implant position was varied up to 2 mm in an anterior and posterior direction and up to 3 mm in a lateral direction. Three different implant heights were simulated. The effect of removing the lateral parts of the annulus was also studied. The implant position and height markedly affect intersegmental rotation and facet joint forces but have hardly any influence on intradiscal pressure in the adjacent discs. Removing the lateral parts of the annulus increases intersegmental rotation and facet joint force mainly for lateral bending and axial rotation. The calculated translation of the mobile implant core is about 1 mm at most, and thus its effect is often overestimated. Great care should be taken to choose the optimal implant height and to insert the implant in the best position for each individual patient.

scholarly journals Biomechanical analysis of a newly developed interspinous process device conjunction with interbody cage based on a finite element model

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243771
Author(s):  
In-Suk Bae ◽  
Koang-Hum Bak ◽  
Hyoung-Joon Chun ◽  
Je Il Ryu ◽  
Sung-Jae Park ◽  
...  
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Finite Element Model ◽  
Element Model ◽  
Axial Rotation ◽  
Biomechanical Analysis ◽  
Interbody Cage ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Interspinous Process Device

Purpose This study aimed to investigate the biomechanical effects of a newly developed interspinous process device (IPD), called TAU. This device was compared with another IPD (SPIRE) and the pedicle screw fixation (PSF) technique at the surgical and adjacent levels of the lumbar spine. Materials and methods A three-dimensional finite element model analysis of the L1-S1 segments was performed to assess the biomechanical effects of the proposed IPD combined with an interbody cage. Three surgical models—two IPD models (TAU and SPIRE) and one PSF model—were developed. The biomechanical effects, such as range of motion (ROM), intradiscal pressure (IDP), disc stress, and facet loads during extension were analyzed at surgical (L3-L4) and adjacent levels (L2-L3 and L4-L5). The study analyzed biomechanical parameters assuming that the implants were perfectly fused with the lumbar spine. Results The TAU model resulted in a 45%, 49%, 65%, and 51% decrease in the ROM at the surgical level in flexion, extension, lateral bending, and axial rotation, respectively, when compared to the intact model. Compared to the SPIRE model, TAU demonstrated advantages in stabilizing the surgical level, in all directions. In addition, the TAU model increased IDP at the L2-L3 and L4-L5 levels by 118.0% and 78.5% in flexion, 92.6% and 65.5% in extension, 84.4% and 82.3% in lateral bending, and 125.8% and 218.8% in axial rotation, respectively. Further, the TAU model exhibited less compensation at adjacent levels than the PSF model in terms of ROM, IDP, disc stress, and facet loads, which may lower the incidence of the adjacent segment disease (ASD). Conclusion The TAU model demonstrated more stabilization at the surgical level than SPIRE but less stabilization than the PSF model. Further, the TAU model demonstrated less compensation at adjacent levels than the PSF model, which may lower the incidence of ASD in the long term. The TAU device can be used as an alternative system for treating degenerative lumbar disease while maintaining the physiological properties of the lumbar spine and minimizing the degeneration of adjacent segments.

scholarly journals The lumbar spine has an intrinsic shape specific to each individual that remains a characteristic throughout flexion and extension

2014 ◽  
Vol 23 (S1) ◽  
pp. 26-32 ◽  
Author(s):  
Anastasia V. Pavlova ◽  
Judith R. Meakin ◽  
Kay Cooper ◽  
Rebecca J. Barr ◽  
Richard M. Aspden
Keyword(s):  
Lumbar Spine ◽  
Intrinsic Shape ◽  
Flexion And Extension

P183. Facet Joint Cyst of the Lumbar Spine: Does it Recur?

2008 ◽  
Vol 8 (5) ◽  
pp. 188S-189S
Author(s):  
Farouq Al-Hamdan
Keyword(s):  
Lumbar Spine ◽  
Facet Joint

Hybrid dynamic stabilization: a biomechanical assessment of adjacent and supraadjacent levels of the lumbar spine

2012 ◽  
Vol 17 (3) ◽  
pp. 232-242 ◽  
Author(s):  
Prasath Mageswaran ◽  
Fernando Techy ◽  
Robb W. Colbrunn ◽  
Tara F. Bonner ◽  
Robert F. McLain
Keyword(s):  
Lumbar Spine ◽  
Lumbar Fusion ◽  
Industrial Robot ◽  
Pedicle Screws ◽  
Axial Rotation ◽  
Dynamic Stabilization ◽  
Follower Load ◽  
Lateral Bending ◽  
Intact Specimen ◽  
Flexion Extension

Object The object of this study was to evaluate the effect of hybrid dynamic stabilization on adjacent levels of the lumbar spine. Methods Seven human spine specimens from T-12 to the sacrum were used. The following conditions were implemented: 1) intact spine; 2) fusion of L4–5 with bilateral pedicle screws and titanium rods; and 3) supplementation of the L4–5 fusion with pedicle screw dynamic stabilization constructs at L3–4, with the purpose of protecting the L3–4 level from excessive range of motion (ROM) and to create a smoother motion transition to the rest of the lumbar spine. An industrial robot was used to apply continuous pure moment (± 2 Nm) in flexion-extension with and without a follower load, lateral bending, and axial rotation. Intersegmental rotations of the fused, dynamically stabilized, and adjacent levels were measured and compared. Results In flexion-extension only, the rigid instrumentation at L4–5 caused a 78% decrease in the segment's ROM when compared with the intact specimen. To compensate, it caused an increase in motion at adjacent levels L1–2 (45.6%) and L2–3 (23.2%) only. The placement of the dynamic construct at L3–4 decreased the operated level's ROM by 80.4% (similar stability as the fusion at L4–5), when compared with the intact specimen, and caused a significant increase in motion at all tested adjacent levels. In flexion-extension with a follower load, instrumentation at L4–5 affected only a subadjacent level, L5–sacrum (52.0%), while causing a reduction in motion at the operated level (L4–5, −76.4%). The dynamic construct caused a significant increase in motion at the adjacent levels T12–L1 (44.9%), L1–2 (57.3%), and L5–sacrum (83.9%), while motion at the operated level (L3–4) was reduced by 76.7%. In lateral bending, instrumentation at L4–5 increased motion at only T12–L1 (22.8%). The dynamic construct at L3–4 caused an increase in motion at T12–L1 (69.9%), L1–2 (59.4%), L2–3 (44.7%), and L5–sacrum (43.7%). In axial rotation, only the placement of the dynamic construct at L3–4 caused a significant increase in motion of the adjacent levels L2–3 (25.1%) and L5–sacrum (31.4%). Conclusions The dynamic stabilization system displayed stability characteristics similar to a solid, all-metal construct. Its addition of the supraadjacent level (L3–4) to the fusion (L4–5) did protect the adjacent level from excessive motion. However, it essentially transformed a 1-level lumbar fusion into a 2-level lumbar fusion, with exponential transfer of motion to the fewer remaining discs.

A Digitizing Technique for the Study of Movement of Intradiscal Dye in Response to Flexion and Extension of the Lumbar Spine

Spine ◽  
1988 ◽  
Vol 13 (3) ◽  
pp. 309-312 ◽  
Author(s):  
BROCK E. SCHNEBEL ◽  
JAMES W. SIMMONS ◽  
JON CHOWNING ◽  
RON DAVIDSON
Keyword(s):  
Lumbar Spine ◽  
Flexion And Extension
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