scholarly journals Biomechanical Comparison of Three Kinds of Minimally Invasive Internal Fixation in the Treatment of Pelvic Bilateral Anterior Ring Fractures

2020 ◽  
Author(s):  
Yong Zhao ◽  
Yupeng Ma ◽  
Dexin Zou ◽  
Xiujiang Sun ◽  
Gong Cheng ◽  
...  
Keyword(s):  
Element Model ◽  
Pelvic Injury ◽  
Hip Joints ◽  
Posterior Displacement ◽  
System Combination ◽  
Rod System ◽  
Anterior Ring ◽  
Fracture Stability ◽  
Intramedullary Screw ◽  
Anterior Posterior

Abstract [Objective] To compare the mechanical characteristics of percutaneous long plate, percutaneous pubic superioris intramedullary screw and percutaneous pelvic anterior screw-rod system for the treatment of bilateral vertical pubic fractures to provide reference for clinical application. [Methods] A finite element model of pelvic anterior ring injury (bilateral vertical pubic fracture) was produced. The fractures were fixed with percutaneous long plate, percutaneous pubic superioris intramedullary screw, percutaneous pelvic anterior screw-rod system and their combination in 5 types of models. The fracture stability under vertical, bilateral and anterior-posterior load were quantified and compared based on the displacement of the hip joints’ midpoint as quantificational index of fracture stability. [Results] In condition of bilateral and anterior-posterior load, the vertical, bilateral and anterior-posterior displacement of the hip joints’ midpoint of different models were significantly different respectively. In general, the displacement of the 5 pelvic anterior ring fixation models were ranked from maximum to minimum as follows: long plate, pelvic anterior screw-rod system, combination of long plate and pelvic anterior screw-rod system, pubic superioris intramedullary screw and combination of pubic superioris intramedullary screw and pelvic anterior screw-rod system. [Conclusion] For the fixation in bilateral pubic fractures of pelvic injury, the percutaneous pubic superioris intramedullary screw was optimal, percutaneous pelvic anterior screw-rod system was the second choice, and percutaneous long plate ranked the third. The percutaneous pelvic anterior screw-rod system can significantly increase fixation stability of the percutaneous pubic superioris intramedullary screw and the percutaneous long plate.

scholarly journals Derivation of a finite-element model of lingual deformation during swallowing from the mechanics of mesoscale myofiber tracts obtained by MRI

2010 ◽  
Vol 109 (5) ◽  
pp. 1500-1514 ◽  
Author(s):  
Srboljub M. Mijailovich ◽  
Boban Stojanovic ◽  
Milos Kojic ◽  
Alvin Liang ◽  
Van J. Wedeen ◽  
...  
Keyword(s):  
Finite Element ◽  
Connective Tissue ◽  
Diffusion Tensor ◽  
Element Model ◽  
Out Of Plane ◽  
Posterior Direction ◽  
Elastic Constraints ◽  
The Relationship ◽  
Passive Muscle ◽  
Anterior Posterior

To demonstrate the relationship between lingual myoarchitecture and mechanics during swallowing, we performed a finite-element (FE) simulation of lingual deformation employing mesh aligned with the vector coordinates of myofiber tracts obtained by diffusion tensor imaging with tractography in humans. Material properties of individual elements were depicted in terms of Hill's three-component phenomenological model, assuming that the FE mesh was composed of anisotropic muscle and isotropic connective tissue. Moreover, the mechanical model accounted for elastic constraints by passive and active elements from the superior and inferior directions and the effect of out-of-plane muscles and connective tissue. Passive bolus effects were negligible. Myofiber tract activation was simulated over 500 ms in 1-ms steps following lingual tip association with the hard palate and incorporated specifically the accommodative and propulsive phases of the swallow. Examining the displacement field, active and passive muscle stress, elemental stretch, and strain rate relative to changes of global shape, we demonstrate that lingual reconfiguration during these swallow phases is characterized by (in sequence) the following: 1) lingual tip elevation and shortening in the anterior-posterior direction; 2) inferior displacement related to hyoglossus contraction at its inferior-most position; and 3) dominant clockwise rotation related to regional contraction of the genioglossus and contraction of the hyoglossus following anterior displacement. These simulations demonstrate that lingual deformation during the indicated phases of swallowing requires temporally patterned activation of intrinsic and extrinsic muscles and delineate a method to ascertain the mechanics of normal and pathological swallowing.

Comparison Between Single Level and Bi-Level Dynamic Stabilization in Lumbar Spondylolisthesis: A Finite Element Study

2007 ◽  
Author(s):  
A. S. Khere ◽  
A. Kiapour ◽  
J. Jangra ◽  
V. K. Goel ◽  
A. Biyani ◽  
...  
Keyword(s):  
Finite Element ◽  
Severe Pain ◽  
Element Model ◽  
Dynamic Stabilization ◽  
Single Level ◽  
Pars Interarticularis ◽  
Lumbar Spondylolisthesis ◽  
Older Populations ◽  
The Finite Element Model ◽  
Anterior Posterior

Lumbar spondylolisthesis is an extension of spondylolysis in which breakage of the vertebrae occurs at the pars interarticularis causing the vertebrae to slip forward. Spondylolisthesis is seen in both younger and older populations with most lesions occurring at the L4-L5 or L5-S1 level. Although the forward slippage of the vertebra does not usually exceed 30% of the body’s anterior-posterior width, possible spinal stenosis and nerve impingement may lead to severe pain and other complications. The purpose of this study is to determine the effect of single level and bi-level dynamic stabilization in reducing the spondylolisthesis. We used the finite element model for this purpose since it is not practical to procure specimens with spondylolisthesis for an experimental investigation.

scholarly journals Pott’s Disease in a 2-Year-Old Child Treated by Decompression and Anterior-Posterior Instrumented Fusion

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Mehmet Nuri Erdem ◽  
Cem Sever ◽  
Mehmet Fatih Korkmaz ◽  
Sinan Karaca ◽  
Ferit Kirac ◽  
...  
Keyword(s):  
Posterior Instrumentation ◽  
Spinal Tuberculosis ◽  
Vertebral Osteomyelitis ◽  
Pedicle Screws ◽  
Early Mobilization ◽  
Instrumented Fusion ◽  
Pott’S Disease ◽  
Rod System ◽  
Paraspinal Abscess ◽  
Anterior Posterior

Introduction. Paraplegia and kyphotic deformity are two major disease-related problems of spinal tuberculosis, especially in the early age disease. In this study a 2-year-old boy who underwent surgical decompression, correction, and 360° instrumented fusion via simultaneous anterior-posterior technique for Pott’s disease was reported.Case Report. A 2-year-and-9-month-old boy presented with severe back pain and paraparesis of one-month duration. Thoracic magnetic resonance imaging demonstrated destruction with a large paraspinal abscess involving T5-T6-T7 levels, compressing the spinal cord. The paraspinal abscess drained and three-level corpectomy was performed at T5-6-7 with transthoracic approach. Anterior instrumentation and fusion was performed with structural 1 autogenous fibula and rib graft using screw-rod system. In prone position pedicle screws were inserted at T4 and T8 levels and rods were placed. Six months after surgery, there was no weakness or paraparesis and no correction loss at the end of follow-up period.Discussion. In cases of vertebral osteomyelitis with severe anterior column destruction in the very early child ages the use of anterior structural grafts and instrumentation in combination with posterior instrumentation is safe and effective in maintenance of the correction achieved and allows efficient stabilization and early mobilization.

scholarly journals A biomechanics study about the mechanism of ligaments injury in anterior posterior compression type Ⅱ pelvic injury

2020 ◽  
Author(s):  
xiaolong Shui ◽  
Jianzhong kong ◽  
Yupeng Chu ◽  
Chengwei Zhou ◽  
Shuaibo Sun ◽  
...  
Keyword(s):  
Sacroiliac Joint ◽  
Rotation Angle ◽  
External Rotation ◽  
Pubic Symphysis ◽  
Separation Distance ◽  
Pelvic Injury ◽  
Control Group ◽  
Sacrospinous Ligament ◽  
Restricted Group ◽  
Anterior Posterior

Abstract Background The anterior and posterior compression (APC) pelvis fracture is a classic pelvic injury, and APC type II is considered to be a typical one caused by the destruction of pelvic ligaments, while the mechanism of ligaments injury and treatment of which is still controversial. This study aims to explore ligaments injury in anterior posterior compression(APC)type II pelvic injury. Method: Fourteen human cadaveric pelvis samples (5 female, 9 male) with the sacrospinous, sacrotuberous, anterior sacroiliac ligaments and partial bone retaining unilaterally were made for this study. To simulate the APC pattern pelvic injury, the samples were divided into two groups randomly, set one group as hemipelvis restricted group (experimental group) and the other one as unrestricted group (control group). According to the biomechanical data, eye observation, motion capture system and real-time video system to record the separation distance of the pubic symphysis and anterior sacroiliac joint, external rotation angle and force when the anterior sacroiliac ligament ruptured. Continuing the external rotation violence, observing the bone and posterior ligaments change since sacrospinous and sacrotuberous ligaments from being damaged to completely ruptured. Result When anterior sacroiliac ligament failed, the mean separation distance of pubic symphysis and anterior sacroiliac joint between restricted group and unrestricted group was 28.6 ± 8.4 mm to 23.6 ± 8.2 mm(P = 0.11) and 11.4 ± 3.8 mm to 9.7 ± 3.9 mm (P = 0.30) respectively. In addition, the external rotation angle and force was 33.9 ± 5.5° to 48.9 ± 5.2°(P < 0.01) and 553.9 ± 82.6 N to 756.6 ± 41.4 N (P < 0.01) respectively. The two distances were not significantly different (P > 0.05), however, the external rotation angle and violence was significantly different (P < 0.05), which was bigger in the unrestricted group. In the unrestricted group, when anterior sacroiliac ligament ruptured, no distinct sacrospinous or sacrotuberous ligaments injury was observed, but in the restricted group, all of samples had two ligaments injury and even two samples had ligaments failed. Moreover, with the extreme external rotation violence continuing, there was still no sacrospinous or sacrotuberous ligaments injury in the unrestricted group. But interosseous sacroiliac ligament, posterior sacroiliac ligaments injury and slight sagittal rotation and sacroiliac joint displacement appeared. In the control group, the sacrospinous ligament ruptured firstly and then the sacrotuberous ligament ruptured. When both of the two ligaments failed, the interosseous sacroiliac ligament was damaged while posterior ligament was not. In the restricted group, when all of the anterior sacroiliac ligament, sacrospinous ligament or sacrotuberous ligament failed, mean separation distance of pubic symphysis and anterior sacroiliac joint increased significantly (from 28.6 ± 8.4 to 42.0 ± 7.6 mm, 11.4 ± 3.8 to 16.7 ± 4.2 mm respectively, all P < 0.05). Conclusion We have three main findings: First, pelvic external rotation injury can divide into two situations: hemipelvis is restricted and unrestricted, which result into two different outcomes. When anterior sacroiliac ligament rupture, the unrestricted group needs more external rotation angle and force, without obvious sacrotuberous or sacrospinous ligaments injury. But in the restricted group, both of two ligaments injury appear. Second, when anterior sacroiliac ligament fail, pubic symphysis displacement ranges from 14 to 40 mm, which has a high fluctuation. Third, when the anterior sacroiliac ligament is damaged, we dose not observe the inevitable destruction of the pelvic floor ligaments (sacrospinous ligament and sacrotubercular ligament).

scholarly journals A biomechanics study on ligamentous injury in anterior posterior compression type II pelvic injury

2020 ◽  
Author(s):  
jianzhong kong ◽  
Yupeng Chu ◽  
Chengwei Zhou ◽  
shuaibo Sun ◽  
guodong Bao ◽  
...  
Keyword(s):  
Sacroiliac Joint ◽  
Rotation Angle ◽  
External Rotation ◽  
Pubic Symphysis ◽  
Pelvic Injury ◽  
Pelvic Bone ◽  
Type Ii ◽  
Significant Difference ◽  
Joint Separation ◽  
Anterior Posterior

Abstract Background: Anterior posterior compression (APC) type II pelvis fracture is caused by the destruction of pelvic ligaments. This study aims to explore ligaments injury in APC type II pelvic injury.Method: Fourteen human cadaveric pelvis samples with sacrospinous ligament (SPL), sacrotuberous ligament (SBL), anterior sacroiliac ligament (ASL), and partial bone retaining unilaterally were acquired for this study. They were randomly divided into hemipelvis restricted and unrestricted groups. We recorded the separation distance of the pubic symphysis and anterior sacroiliac joint, external rotation angle, and force when ASL ruptured. We observed the external rotation damage to the pelvic bone and ligaments.Result: When ASL failed, there was no significant difference in pubic symphysis separation (28.6 ± 8.4 mm to 23.6 ± 8.2 mm, P = 0.11) and anterior sacroiliac joint separation (11.4 ± 3.8 mm to 9.7 ± 3.9 mm, P = 0.30) between restricted and unrestricted groups. The external rotation angle (33.9 ± 5.5° to 48.9 ± 5.2°, P < 0.01) and force (553.9 ± 82.6 N to 756.6 ± 41.4 N, P < 0.01) were significantly different. Pubic symphysis separation between two groups ranged from 14 mm to 40 mm. In the restricted group, both SBL and SPL were injured. SPL ruptured first, and then SBL and the interosseous sacroiliac ligament were damaged while the posterior ligament remained unharmed. In the unrestricted group, interosseous sacroiliac ligament and posterior sacroiliac ligaments were damaged, while SBL and SPL were not. When the ASL, SBL, and SPL all failed, pubic symphysis and anterior sacroiliac joint separation between two groups increased significantly (from 28.6 ± 8.4 to 42.0 ± 7.6 mm, 11.4 ± 3.8 to 16.7 ± 4.2 mm respectively, all P < 0.05).Conclusion: Pelvic external rotation injury is either hemipelvic restricted or unrestricted, which can result in different outcomes. When the ASL ruptures, the unrestricted group needs greater external rotation angle and force, without SBL or SPL injury, while both SBL and SPL were injured in another group. When ASL fails in two groups, pubic symphysis separation fluctuates considerably. Finally, when the ASL ruptures, SBL and SPL may be undamaged.

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