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Lawrence G. Lenke - One of the best experts on this subject based on the ideXlab platform.

  • Biomechanical Analysis of derotation of the thoracic spine using pedicle screws.
    Spine, 2010
    Co-Authors: Ivan Cheng, Alex Iezza, Derek P Lindsey, Lawrence G. Lenke
    Abstract:

    Biomechanical Analysis of derotational load-to-failure of pedicle screw (PS) instrumentation in cadaveric thoracic spinal segments. To investigate the derotational torque that can be applied to the thoracic spine through different linked constructs and evaluate the modes of failure. Thoracic derotation with PSs has been shown to provide better 3 plane correction than other methods but the effects of linked PS constructs has not been studied. Four groups of thoracic segments with different PS constructs were loaded to failure with a rotational torque applied to the construct to simulate the left to right derotational force applied to a typical idiopathic dextrorotary thoracic scoliosis curve. Single screw T4 segments instrumented on the medial (group 1M) and lateral (group 1L) sides, bilaterally-linked T5 segments (group 2), unilaterally-linked T6-T9 segments on the medial (group 3M) and lateral (group 3L) sides, and quadrangularly-linked T6-T9 segments (group 4) were loaded with MTS machine in a simulated thoracic derotation model. Single T4 PSs on the medial and lateral sides failed at 4.0 +/- 1.4 Nm (group 1M) and 6.1 +/- 2.5 Nm (group 1L), respectively. Bilaterally-linked T5 screws failed at 11.9 +/- 3.1 Nm (group 2). Unilaterally linked T6-T9 PS constructs on the medial and lateral sides failed at 21.2 +/- 7.5 Nm (group 3M) and 17.9 +/- 11.1 Nm (group 3L), respectively. Quadrangularly-linked PSs failed at 42.5 +/- 14.5 Nm (group 4). CONCLUSION.: A near linear increase in relative torque applied before failure was found with each additional PS linked. Linked constructs allow for significantly greater torque with less risk of PS breach of the spinal canal.

Ivan Cheng - One of the best experts on this subject based on the ideXlab platform.

  • Biomechanical Analysis of derotation of the thoracic spine using pedicle screws.
    Spine, 2010
    Co-Authors: Ivan Cheng, Alex Iezza, Derek P Lindsey, Lawrence G. Lenke
    Abstract:

    Biomechanical Analysis of derotational load-to-failure of pedicle screw (PS) instrumentation in cadaveric thoracic spinal segments. To investigate the derotational torque that can be applied to the thoracic spine through different linked constructs and evaluate the modes of failure. Thoracic derotation with PSs has been shown to provide better 3 plane correction than other methods but the effects of linked PS constructs has not been studied. Four groups of thoracic segments with different PS constructs were loaded to failure with a rotational torque applied to the construct to simulate the left to right derotational force applied to a typical idiopathic dextrorotary thoracic scoliosis curve. Single screw T4 segments instrumented on the medial (group 1M) and lateral (group 1L) sides, bilaterally-linked T5 segments (group 2), unilaterally-linked T6-T9 segments on the medial (group 3M) and lateral (group 3L) sides, and quadrangularly-linked T6-T9 segments (group 4) were loaded with MTS machine in a simulated thoracic derotation model. Single T4 PSs on the medial and lateral sides failed at 4.0 +/- 1.4 Nm (group 1M) and 6.1 +/- 2.5 Nm (group 1L), respectively. Bilaterally-linked T5 screws failed at 11.9 +/- 3.1 Nm (group 2). Unilaterally linked T6-T9 PS constructs on the medial and lateral sides failed at 21.2 +/- 7.5 Nm (group 3M) and 17.9 +/- 11.1 Nm (group 3L), respectively. Quadrangularly-linked PSs failed at 42.5 +/- 14.5 Nm (group 4). CONCLUSION.: A near linear increase in relative torque applied before failure was found with each additional PS linked. Linked constructs allow for significantly greater torque with less risk of PS breach of the spinal canal.

Masatomo Yamanaka - One of the best experts on this subject based on the ideXlab platform.

  • Biomechanical Analysis of rehabilitation in the standing position.
    The American journal of sports medicine, 1991
    Co-Authors: Yasumitsu Ohkoshi, Kazunori Yasuda, Kiyoshi Kaneda, Tatsuhiko Wada, Masatomo Yamanaka
    Abstract:

    Biomechanical Analysis of the two-dimensional models composed from roentgenographic pictures and electromyographic Analysis of the shear force exerted on the tibia during standing on both legs were conducted in 21 young adult males. The simultaneous contraction of the quadriceps and hamstrings was observed in all electromyograms. Amplitude observed on electromyograms of the hamstrings increased as the trunk flexion angle increased. The calculated average values of shear force were negative at every knee flexion angle (negative value means posteriorly directed force). As the trunk flexion angle increased, posterior drawer force increased at knee flexion angles of 30 degrees and 60 degrees. The simultaneous contraction of the quadriceps and the hamstrings was considered to be the main factor that influenced these results. Standing on both legs with knee and trunk flexion was considered to be applicable in the early stages after anterior cruciate ligament reconstruction.

Hyun W Bae - One of the best experts on this subject based on the ideXlab platform.

  • Biomechanical Analysis in a human cadaveric model of spinous process fixation with an interlaminar allograft spacer for lumbar spinal stenosis laboratory investigation
    Journal of Neurosurgery, 2012
    Co-Authors: Ben B Pradhan, Alexander W L Turner, Michael A Zatushevsky, Bryan G Cornwall, Sean S Rajaee, Hyun W Bae
    Abstract:

    Object Traditional posterior pedicle screw fixation is well established as the standard for spinal stabilization following posterior or posterolateral lumbar fusion. In patients with lumbar spinal stenosis requiring segmental posterior instrumented fusion and decompression, interlaminar lumbar instrumented fusion (ILIF) is a potentially less invasive alternative with reduced morbidity and includes direct decompression assisted by an interlaminar allograft spacer stabilized by a spinous process plate. To date, there has been no Biomechanical study on this technique. In the present study the Biomechanical properties of the ILIF construct were evaluated using an in vitro cadaveric Biomechanical Analysis, and the results are presented in comparison with other posterior fixation techniques. Methods Eight L1–5 cadaveric specimens were subjected to nondestructive multidirectional testing. After testing the intact spine, the following conditions were evaluated at L3–4: bilateral pedicle screws, bilateral laminoto...

J. Marciniak - One of the best experts on this subject based on the ideXlab platform.

  • Metatarsal Osteotomy Using Double-Threaded Screws - Biomechanical Analysis
    Advances in Intelligent and Soft Computing, 2010
    Co-Authors: A. Ziębowicz, Anita Kajzer, Wojciech Kajzer, J. Marciniak
    Abstract:

    The fundamental purpose of this research was to determine the Biomechanical characteristics of the first metatarsal bone - double-threaded screws system made of stainless steel (Cr-Ni-Mo) and an assessment of its stability. To define the Biomechanical characteristics of the system, the finite element method and experimental method were applied. Geometric models of metatarsal bone and double-threaded screws, were discretized by means of SOLID 95 element. Appropriate boundary conditions imitating phenomena in the real system with appropriate accuracy were established. The aim of Biomechanical Analysis was calculation of displacements and stresses in the bone and the stabilizers in a function of the applied loading. The experimental method was carried out to calculate displacements of the analyzed system. The obtained results can be applied to determine the construction features of the stabilizer and to select mechanical properties of metallic biomaterial (selection of degree of strain hardening).

  • Biomechanical Analysis of plate stabilization on cervical part of spine
    Archives of materials science and engineering, 2009
    Co-Authors: Martin Kiel, Janusz Szewczenko, J. Marciniak, Marcin Basiaga, Wojciech Wolański
    Abstract:

    Purpose: The main aim of the work was determination of Biomechanical Analysis of cervical spine – stabilizer system made of stainless steel (Cr-Ni-Mo) and Ti-6Al-4V alloy. Design/methodology/approach: To define Biomechanical characteristic of the system the finite elements method (FEM) was applied. Geometric model of part of spine C5-C7 and stabilizer were discretized by SOLID95 element. Appropriate boundary conditions imitating phenomena in real system with appropriate accuracy were established. Findings: The result of Biomechanical Analysis was calculation of displacements and stresses in the vertebras and the stabilizer in a function of the applied loading: 50-300 N for the stabilizer made of stainless steel (Cr-Ni-Mo) and Ti-6Al-4V alloy. Research limitations/implications: The result of Biomechanical Analysis for plate stabilizer obtained by FEM can be use to determine a construction features of the stabilizer, and to select mechanical properties of metallic biomaterial and estimation of stabilization quality. The calculation of displacements for part C5-C7 show that the proposed type of stabilizer enables correct stabilization used to clinical apply. Practical implications: The results of Biomechanical Analysis showed correct mechanical properties used to made the plate stabilizer. Originality/value: The obtained numerical results should be verified in “in vitro” tests.

  • Biomechanical Analysis of lumbar spine stabilization by means of transpedicular stabilizer
    Information Technologies in Biomedicine, 2008
    Co-Authors: J. Marciniak, Janusz Szewczenko, Marcin Basiaga, Witold Walke, Martin Kiel, Ilona Manka
    Abstract:

    The fundamental purpose of research was determination of Biomechanical characteristic of lumbar spine–transpedicular stabilizer system made of stainless steel (Cr-Ni-Mo) and Ti6Al4V alloy. To define Biomechanical characteristic of the system finite element method was applied. Geometric models of part spine L3-L4 and stabilizer, was discretised by means of SOLID 95 element. Appropriate boundary conditions imitating phenomena in real system with appropriate accuracy were established. The aim of Biomechanical Analysis was calculation of displacements and stresses in the vertebras and the stabilizer in a function of the applied loading: 700 N–1600 N. The results of the numerical Analysis can be applied to determine a construction features of the stabilizer, and to select mechanical properties of metallic biomaterial. The defined displacements for vertebras L3-L4 show that the proposed type of stabilizer enables correct course of treatment.

  • Biomechanical Analysis of tibia - double threaded screw fixation
    Archives of materials science and engineering, 2008
    Co-Authors: Witold Walke, J. Marciniak, Zbigniew Paszenda, Marcin Kaczmarek
    Abstract:

    Purpose: The aim of the work was determination of Biomechanical characteristics of a tibia – double threaded screw system with the use of finite element method. Design/methodology/approach: Geometrical model of the tibia was worked out on the basis of data from computer tomography of real bone. Geometrical model of the double threaded screw was prepared in ANSYS v. 11. Meshing was realized with the use of SOLID95 elements, applied in analyses of volumes. The model was loaded with forces in the range F = 100-2000 N. Findings: Initial Biomechanical Analysis, carried out with the use of finite element method, showed usefulness of the analyzed form of the double threaded screw made of Ti6Al4V alloy in fractured tibia treatment. Research limitations/implications: Due to applied simplifications of the tibia – double threaded screw fixation model, the Analysis results should be experimentally verified in laboratory conditions. Originality/value: The obtained Biomechanical characteristics of the tibia – double threaded screw system (u = f(F), σmax = f(F)) are the basis for selection of degree of strain hardening of the applied metallic biomaterial and optimization of geometrical features of the analyzed form of implant. Appropriate selection of mechanical properties and geometrical features of the implant is the main factor determining a stability of the fixation.

  • Information Technologies in Biomedicine - Biomechanical Analysis of Plate for Corrective Osteotomy of Tibia
    Advances in Soft Computing, 1
    Co-Authors: J. Marciniak, Witold Walke, Marcin Kaczmarek, Jerzy Cieplak
    Abstract:

    The aim of the work was assessment of system for corrective osteotomy of tibia (patent no. P382316). The system consisted of the plate of shape adapted to anatomical curvature of bone and the distance block, assembled together with the plate by means of connective screws. Biomechanical Analysis of the tibia – plate system was carried our for the implant made of two biomaterials used in bone surgery – stainless steel and Ti-6Al-4V alloy. Finite element method was applied to calculate displacements, strains and stresses. The obtained results allowed to work out Biomechanical characteristics of the analyzed system. These characteristics can be a basis for selection of degree of strain hardening of the applied metallic biomaterial and optimization of the plate’s geometry.