Lumbar model generator: a tool for the automated generation of a parametric scalable model of the lumbar spine

Low back pain is a major cause of disability and requires the development of new devices to treat pathologies and improve prognosis following surgery. Understanding the effects of new devices on the biomechanics of the spine is crucial in the development of new effective and functional devices. The aim of this study was to develop a preliminary parametric, scalable and anatomically accurate finite-element model of the lumbar spine allowing for the evaluation of the performance of spinal devices. The principal anatomical surfaces of the lumbar spine were first identified, and then accurately fitted from a previous model supplied by S14 Implants (Bordeaux, France). Finally, the reconstructed model was defined according to 17 parameters which are used to scale the model according to patient dimensions. The developed model, available as a toolbox named the lumbar model generator, enables generating a population of models using subject-specific dimensions obtained from data scans or averaged dimensions evaluated from the correlation analysis. This toolbox allows patient-specific assessment, taking into account individual morphological variation. The models have applications in the design process of new devices, evaluating the biomechanics of the spine and helping clinicians when deciding on treatment strategies.

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A Finite Element Study of the Combined Effect of Fusion and Disc Degeneration on Adjacent Levels of the Lumbar Spine

Advances in Bioengineering ◽

10.1115/imece2003-43096 ◽

2003 ◽

Author(s):

Lakshminarayan Hariharan ◽

Farid Amirouche ◽

Ravikumar Varadarajan

Keyword(s):

Finite Element ◽

Low Back Pain ◽

Back Pain ◽

Lumbar Spine ◽

Disc Degeneration ◽

Degenerative Spondylolisthesis ◽

Element Model ◽

Adjacent Segment ◽

Low Back ◽

Common Solution

Intervertebral disc degeneration is believed to be the main cause of low back pain and has mostly been treated with lumbar interbody fusion or arthrodesis. Although fusion is a very common solution to low back pain it has been associated with disc degeneration and degenerative spondylolisthesis in the adjacent segment. A number of studies have been performed to study the effect of fusion, however there has not been any significant study to observe a fused spine with a degenerated disc at an adjacent level. This study involved a finite element model of the Lumbar spine L1-L5 which was fused with a bone graft at the L4-L5 level and degenerated in two stages at the L3-L4 level and also analyzed with reduced disc heights all in different cases.

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Biomechanical Analysis in the Lumbar Spine During Two-Step Traction Therapy

Volume 3: 16th International Conference on Advanced Vehicle Technologies; 11th International Conference on Design Education; 7th Frontiers in Biomedical Devices ◽

10.1115/detc2014-35701 ◽

2014 ◽

Author(s):

Yoon Hyuk Kim ◽

Won Man Park ◽

Kyungsoo Kim

Keyword(s):

Lumbar Spine ◽

Annulus Fibrosus ◽

Three Dimensional ◽

Element Model ◽

Biomechanical Analysis ◽

Low Back ◽

Spine Biomechanics ◽

Dimensional Finite Element ◽

Axial Traction ◽

Three Dimensional Finite Element

Traction therapy is a widely used conservative treatment for low back pain. However, the effects of traction therapy on lumbar spine biomechanics are not well known. We investigated biomechanical effects of two-step traction therapy, which consists of global axial traction and local decompression, on the lumbar spine using a validated three-dimensional finite element model of the lumbar spine. One-third of body weight was applied at the center of the L1 vertebra toward the superior direction for the first axial traction. Anterior translation of L4 spinal bone was considered as the second local decompression. The lordosis angle between the superior planes of the L1 vertebra and sacrum was 44.6° at baseline, 35.2° with global axial traction, and 46.4° with local decompression. The fibers of annulus fibrosus in the posterior region, and intertransverse and posterior longitudinal ligaments experienced stress primarily during global axial traction, these stresses decreased during local decompression. A combination of global axial traction and local decompression would be helpful for reducing tensile stress on the fibers of the annulus fibrosus and ligaments, and intradiscal pressure in traction therapy. The present study could be used to develop a safer and more effective type of traction therapy.

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Patient-Specific Finite Element Model to Simulate the Behaviour of a Scoliotic Spine

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176448 ◽

2007 ◽

Author(s):

Anne Lindberg ◽

Philippe Büchler

Keyword(s):

Finite Element ◽

Lumbar Spine ◽

Adolescent Idiopathic Scoliosis ◽

Element Model ◽

Patient Specific ◽

Growth Spurt ◽

Organ Function ◽

Bony Fusion ◽

Growing Spine ◽

Treatment Surgery

Adolescent idiopathic scoliosis is the most frequent deformity of the growing spine. Scoliosis predominantly affects girls during the adolescent growth spurt. Untreated deformities become social stigmas, are crippling and can compromise organ function. Therefore, uncontrollable progression of curvature and related complex deformities require operative treatment. Surgery is currently the only way to effectively decrease the angle of curvature. Unfortunately, operative methods are still based on principles introduced by Hibbs in 1911 — long, stiff bony fusion of a major portion of the thoracic and/or lumbar spine.

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Body Mass, Nonspecific Low Back Pain, and Anatomical Changes in the Lumbar Spine in Judo Athletes

Journal of Orthopaedic and Sports Physical Therapy ◽

10.2519/jospt.2007.2508 ◽

2007 ◽

Author(s):

Takashi Okada

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Lumbar Spine ◽

Body Mass ◽

Low Back ◽

Anatomical Changes ◽

Judo Athletes

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Faculty Opinions recommendation of The anatomical basis for low back pain. Studies on the presence of sensory nerve endings in ligamentous, capsular and intervertebral disc structures in the human lumbar spine.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726427730.793519836 ◽

2016 ◽

Author(s):

Massimo Allegri

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Lumbar Spine ◽

Intervertebral Disc ◽

Sensory Nerve ◽

Nerve Endings ◽

Low Back ◽

Sensory Nerve Endings ◽

Anatomical Basis ◽

Human Lumbar Spine

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Severe low back pain with mild leg symptoms due to lumbar spine stenosis

British Journal of Neurosurgery ◽

10.1080/02688697.2020.1868402 ◽

2021 ◽

pp. 1-4

Author(s):

Ryo Kanematsu ◽

Junya Hanakita ◽

Toshiyuki Takahashi ◽

Manabu Minami ◽

Kazuhiro Miyasaka ◽

...

Keyword(s):

Low Back Pain ◽

Back Pain ◽

Lumbar Spine ◽

Low Back

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Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

Scientific Reports ◽

10.1038/s41598-021-93821-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Niksa Mohammadi Bagheri ◽

Mahmoud Kadkhodaei ◽

Shiva Pirhadi ◽

Peiman Mosaddegh

Keyword(s):

Clinical Data ◽

Three Dimensional ◽

Element Model ◽

Von Mises Stress ◽

Patient Specific ◽

Average Error ◽

Constant Thickness ◽

Arc Length ◽

Implementation Techniques ◽

Von Mises

AbstractThe implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ($$\text {K}_{\text{mean}}$$ K mean ) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower $$\text {K}_{\text{mean}}$$ K mean value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

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