scholarly journals Experimental evaluation of precision and accuracy of RSA in the lumbar spine

2020 ◽  
Author(s):  
Marie Christina Keller ◽  
Christof Hurschler ◽  
Michael Schwarze
Keyword(s):  
Lumbar Spine ◽  
Focal Spot ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Hip And Knee Arthroplasty ◽  
Spinal Region ◽  
Precision And Accuracy ◽  
Bone Structures

Abstract Purpose Roentgen stereophotogrammetric analysis is a technique to make accurate assessments of the relative position and orientation of bone structures and implants in vivo. While the precision and accuracy of stereophotogrammetry for hip and knee arthroplasty is well documented, there is insufficient knowledge of the technique’s precision and, especially accuracy when applied to rotational movements in the spinal region. Methods The motion of one cadaver lumbar spine segment (L3/L4) was analyzed in flexion–extension, lateral bending and internal rotation. The specific aim of this study was to examine the precision and accuracy of stereophotogrammetry in a controlled in vitro setting, taking the surrounding soft tissue into account. The second objective of this study was to investigate the effect of different focal spot values of X-ray tubes. Results Overall, the precision of flexion–extension measurements was found to be better when using a 0.6 mm focal spot value rather than 1.2 mm (± 0.056° and ± 0.153°; respectively), and accuracy was also slightly better for the 0.6 mm focal spot value compared to 1.2 mm (− 0.137° and − 0.170°; respectively). The best values for precision and accuracy were obtained in lateral bending for both 0.6 mm and 1.2 mm focal spot values (precision: ± 0.019° and ± 0.015°, respectively; accuracy: − 0.041° and − 0.035°). Conclusion In summary, the results suggest stereophotogrammetry to be a highly precise method to analyze motion of the lumbar spine. Since precision and accuracy are better than 0.2° for both focal spot values, the choice between these is of minor clinical relevance.

The dynamic flexion/extension properties of the lumbar spine in vitro using a novel pendulum system

2007 ◽  
Vol 40 (12) ◽  
pp. 2767-2773 ◽  
Author(s):  
Joseph J. Crisco ◽  
Lindsey Fujita ◽  
David B. Spenciner
Keyword(s):  
Lumbar Spine ◽  
Pendulum System ◽  
Flexion Extension

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.

Immediate Stiffness of the C5–C6 Segment after Discectomy with the Cloward Technique: An in Vitro Biomechanical Study on a Human Cadaveric Model

Neurosurgery ◽  
2001 ◽  
Vol 49 (6) ◽  
pp. 1399-1408 ◽  
Author(s):  
Andrzej Maciejczak ◽  
Michał Ciach ◽  
Maciej Radek ◽  
Andrzej Radek ◽  
Jan Awrejcewicz
Keyword(s):  
Interbody Fusion ◽  
Spinal Instrumentation ◽  
Axial Rotation ◽  
Postoperative Management ◽  
Biomechanical Study ◽  
Lateral Bending ◽  
Cervical Discectomy ◽  
Cloward Procedure ◽  
Flexion Extension

ABSTRACT OBJECTIVE To determine whether the Cloward technique of cervical discectomy and fusion increases immediate postoperative stiffness of single cervical motion segment after application of interbody dowel bone graft. METHODS We measured and compared the stiffness of single-motion segments in cadaveric cervical spines before and immediately after interbody fusion with the Cloward technique. Changes in range of motion and stiffness of the C5–C6 segment were measured in a bending flexibility test (flexion, extension, lateral bending and axial rotation) before and after a Cloward procedure in 11 fresh-frozen human cadaveric specimens from the 4th through the 7th vertebrae. RESULTS The Cloward procedure produced a statistically significant increase in stiffness of the operated segment in flexion and lateral bending when compared with the intact spine. The less stiff the segment before the operation, the greater the increase in its postoperative flexural stiffness (statistically significant). The Cloward procedure produced nonuniform changes in rotational and extensional stiffness that increased in some specimens and decreased in others. CONCLUSION Our data demonstrate that Cloward interbody fusion increases immediate postoperative stiffness of an operated segment only in flexion and lateral bending in cadaveric specimens in an in vitro environment. Thus, Cloward fusion seems a relatively ineffective method for increasing the stiffness of a construct. This may add to discussion on the use of spinal instrumentation and postoperative management of patients after cervical discectomy, which varies from bracing in hard collars through immobilization in soft collars to no external orthosis.

Mechanical Properties of Human Lumbar Spine Motion Segments—Part I: Responses in Flexion, Extension, Lateral Bending, and Torsion

1979 ◽  
Vol 101 (1) ◽  
pp. 46-52 ◽  
Author(s):  
A. B. Schultz ◽  
D. N. Warwick ◽  
M. H. Berkson ◽  
A. L. Nachemson
Keyword(s):  
Mechanical Properties ◽  
Lumbar Spine ◽  
Mechanical Behavior ◽  
Human Cadaver ◽  
Lateral Bending ◽  
Human Lumbar Spine ◽  
Flexion Extension ◽  
Spine Motion ◽  
Pressure Changes ◽  
Posterior Elements

In this first part of a three-part report, the mechanical behavior of 42 fresh human cadaver lumbar motion segments in flexion, extension, lateral bending, and torsion is examined. Motions and intradiskal pressure changes that occurred in response to these loads, with posterior elements both intact and excised, are reported.

Design and development of a novel expanding flexible rod device (FRD) for stability in the lumbar spine: A finite-element study

2020 ◽  
Vol 43 (12) ◽  
pp. 803-810 ◽  
Author(s):  
Masud Rana ◽  
Sandipan Roy ◽  
Palash Biswas ◽  
Shishir Kumar Biswas ◽  
Jayanta Kumar Biswas
Keyword(s):  
Finite Element ◽  
Lumbar Spine ◽  
Range Of Motion ◽  
Pedicle Screw ◽  
Axial Rotation ◽  
Von Mises Stress ◽  
Lateral Bending ◽  
Intact Bone ◽  
Flexion Extension ◽  
Von Mises

The aim of this study is to design a novel expanding flexible rod device, for pedicle screw fixation to provide dynamic stability, based on strength and flexibility. Three-dimensional finite-element models of lumbar spine (L1-S) with flexible rod device on L3-L4-L5 levels are developed. The implant material is taken to be Ti-6Al-4V. The models are simulated under different boundary conditions, and the results are compared with intact model. In natural model, total range of motion under 10 Nm moment were found 66.7°, 24.3° and 13.59°, respectively during flexion–extension, lateral bending and axial rotation. The von Mises stress at intact bone was 4 ± 2 MPa and at bone, adjacent to the screw in the implanted bone, was 6 ± 3 MPa. The von Mises stress of disc of intact bone varied from 0.36 to 2.13 MPa while that of the disc between the fixed vertebra of the fixation model reduced by approximately 10% for flexion and 25% for extension compared to intact model. The von Mises stresses of pedicle screw were 120, 135, 110 and 90 MPa during flexion, extension, lateral bending, and axial rotation, respectively. All the stress values were within the safe limit of the material. Using the flexible rod device, flexibility was significantly increased in flexion/extension but not in axial rotation and lateral bending. The results suggest that dynamic stabilization system with respect to fusion is more effective for homogenizing the range of motion of the spine.

scholarly journals In Vivo and In Vitro Analysis of Rat Lumbar Spine Mechanics

2010 ◽  
Vol 468 (10) ◽  
pp. 2695-2703 ◽  
Author(s):  
Matthew E. Cunningham ◽  
Jocelyn M. Beach ◽  
Serkan Bilgic ◽  
Oheneba Boachie-Adjei ◽  
Marjolein C. H. van der Meulen ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Spine Mechanics ◽  
Vitro Analysis ◽  
In Vitro Analysis

Kinesis (In-vivo/In-vitro) of L5-S1 lumbar spine

2017 ◽  
Author(s):  
Akmal Widyawan Hardjasudjana ◽  
G. Kosalishkwaran ◽  
S. Parasuraman ◽  
M.K.A. Ahamed Khan ◽  
I. Elamvazuthi
Keyword(s):  
Lumbar Spine

Measuring Dynamic In-Vivo Elbow Kinematics: Description of Technique and Estimation of Accuracy

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Colin P. McDonald ◽  
Vasilios Moutzouros ◽  
Michael J. Bey
Keyword(s):  
Full Extension ◽  
X Ray ◽  
Tracking Technique ◽  
Model Based ◽  
Flexion Extension ◽  
Full Flexion ◽  
Position And Orientation ◽  
Elbow Motion

Background: The objectives of this study were to characterize the translational and rotational accuracy of a model-based tracking technique for quantifying elbow kinematics and to demonstrate its in vivo application. Method of Approach: The accuracy of a model-based tracking technique for quantifying elbow kinematics was determined in an in vitro experiment. Biplane X-ray images of a cadaveric elbow were acquired as it was manually moved through flexion-extension. The 3D position and orientation of each bone was determined using model-based tracking. For comparison, the position and orientation of each bone was also determined by tracking the position of implanted beads with dynamic radiostereometric analysis. Translations and rotations were calculated for both the ulnohumeral and radiohumeral joints, and compared between measurement techniques. To demonstrate the in vivo application of this technique, biplane X-ray images were acquired as a human subject extended their elbow from full flexion to full extension. Results: The in vitro validation demonstrated that the model-based tracking technique is capable of accurately measuring elbow motion, with reported errors averaging less than ±1.0 mm and ±1.0 deg. For the in vivo application, the carrying angle changed from an 8.3 ± 0.5 deg varus position in full flexion to an 8.4 ± 0.5 deg valgus position in full extension. Conclusions: Model-based tracking is an accurate technique for measuring in vivo, 3D, dynamic elbow motion. It is anticipated that this experimental approach will enhance our understanding of elbow motion under normal and pathologic conditions.

Tapered cages in anterior lumbar interbody fusion: biomechanics of segmental reactions

2006 ◽  
Vol 5 (4) ◽  
pp. 330-335 ◽  
Author(s):  
Jason Moore ◽  
Narayan Yoganandan ◽  
Frank A. Pintar ◽  
Jason Lifshutz ◽  
Dennis J. Maiman
Keyword(s):  
Interbody Fusion ◽  
Anterior Lumbar Interbody Fusion ◽  
Lumbar Interbody Fusion ◽  
Lateral Bending ◽  
Related Data ◽  
Flexion Extension ◽  
Before And After ◽  
Bending Modes ◽  
Lumbar Spinal

Object The aim of this study was to determine the in vitro biomechanical responses of lumbar spinal segments after implantation of tapered cages. Methods Range of motion (ROM)– and stiffness-related data were determined in 10 human cadaveric T12–S1 columns subjected to flexion, extension, and lateral bending modes before and after anterior lumbar interbody fusion in which stand-alone LT-CAGE devices were used. The overall column showed no significant changes in ROM or stiffness. At the instrumented level, stiffness increased significantly (p < 0.05) in flexion and lateral bending modes. Indications of instability in extension were present, but these values were not statistically significant. There was no evidence of adjacent-level instability at any level in any mode, except for the segment superior to the fixation level in flexion; here there was a significant increase in ROM (p < 0.05) and a decrease in stiffness. Conclusions The anatomical conformity and bilateral placement of cages provide ample stability and rigidity at the treated level, comparable to that of other cage systems. Because hypermobility is traditionally related to early degenerative changes, the present results appear to suggest that cages do not significantly contribute to such alterations.

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