Study on ECC compression fatigue under different constant lateral compression levels

2021 ◽  
pp. 106630
Author(s):  
Hu Guanhua ◽  
Gao Shuling ◽  
Zhu Yanping
Keyword(s):  
Lateral Compression

Posterior Midline Approach for a C2 Schwannoma: 2-Dimensional Operative Video

2020 ◽  
Author(s):  
Sorin Aldea ◽  
Abdu Alkhairy ◽  
Irina Joitescu ◽  
Caroline Le Guerinel
Keyword(s):  
Posterior Approach ◽  
Main Step ◽  
Surgical Removal ◽  
Posterior Arch ◽  
Favorable Result ◽  
Lateral Compression ◽  
Bone Removal ◽  
Far Lateral ◽  
Midline Approach ◽  
Posterior Midline

Abstract C2 schwannomas are rare lesions that may develop in the spinal canal, in the area of the C2 ganglion situated posterior to the C1C2 articulation, in the extraspinal area or in a combination of these 3 sectors.1,2 The surgical removal of these lesions is delicate because of the intimate relationships the schwannomas develop with the V3 segment of the vertebral artery.  A variety of lateral, far-lateral, or extreme lateral approaches have been described in order to tackle these lesions. We use a posterior midline approach that takes advantage of the predominantly extradural development of C2 schwannomas. In this technique, the main step is the debulking of the posterior articular sector of the tumor, which is easily accessible through a midline posterior approach and necessitates minimal bone removal. In most cases, removal of the homolateral posterior arch of C1 is sufficient in order to create an adequate access. These maneuvers create the necessary space for dissecting both the intradural and extraspinal sectors of the schwannoma.  We present this technique through a case with a minimal intradural component exerting mainly a lateral compression of the spinal cord. The tumor was operated through the midline mini-invasive posterior approach with a favorable result. We demonstrate the surgical technique in video and discuss the nuances.

scholarly journals The traditional experience strategy (TES) and combined ultrasonography examination (CUE) for the treatment of lateral compression type 1 pelvic fractures: a historical control study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hai Huang ◽  
Bin-Fei Zhang ◽  
Ping Liu ◽  
Hong-Li Deng ◽  
Peng-Fei Wang ◽  
...  
Keyword(s):  
Pelvic Fractures ◽  
Definitive Treatment ◽  
Lateral Compression ◽  
Level Of Evidence ◽  
Conservative Group ◽  
Medical Records System ◽  
The Stability ◽  
And Function ◽  
Compression Type

Abstract Background It is difficult to judge the stability of lateral compression type-1 (LC-1) pelvic fracture, as it is often based on static images of the pelvis. Compared with the traditional experience strategy, ultrasonography examination may be able to distinguish operative and conservative patients before definitive treatment. However, in previous studies, we have not compared the outcomes between traditional experience strategy (TES group) and combined ultrasonography examination (CUE group). Thus, the aim of the study is comparing the differences between TES and CUE strategy, to identify the value of ultrasonography examination. Methods Medical records system for patients with LC-1 pelvic fractures who were treated with TES and CUE strategy were included. Patients’ baseline characteristics, treatment strategy, and function were recorded at follow-up. Functional outcomes were evaluated using the Majeed grading system. Results In total, 77 patients with LC-1 pelvic fractures were included in the study. There were 42 and 35 patients in TES and CUE group, respectively. Compared to TES group (69 %), there were less proportion patients chosen the operative treatment in CUE group (43 %, P = 0.021). The volume of intraoperative blood loss in CUE operative group was more than TES operative group (P = 0.037). There were more patients with complete sacral fracture in CUE operative group than TES operative group (P = 0.002). The Majeed scores in CUE conservative group was higher than TES conservative group (P = 0.008). The overall Majeed scores in CUE group was higher than that in TES group (P = 0.039). Conclusions The ultrasonography examination could relatively accurately identify the unstable LC-1 pelvis than the traditional experience strategy, the operative rate could be reduced and the overall function of LC-1 patients could be improved under the ultrasonography examination. Level of evidence Level III.

scholarly journals Mechanism research on crack propagation in coal induced by CO2 phase-transition fracturing under different lateral compression coefficients

2021 ◽  
pp. 014459872110153
Author(s):  
Qingsong Li ◽  
Jinlei Fu ◽  
Xianwei Heng ◽  
Xiaoqian Xu ◽  
Shu Ma
Keyword(s):  
Phase Transition ◽  
Crack Propagation ◽  
Initial Stress ◽  
Main Crack ◽  
Transition Process ◽  
Simulation Software ◽  
Lateral Compression ◽  
Monitoring Point ◽  
Micro Cracks ◽  
Fractured Coal

To study crack propagation around the fracture hole in the coal body induced by high-pressure CO2 gas produced by CO2 phase transition fracturing, the mechanism of permeability enhancement of fractured coal induced by liquid CO2 phase transition fracturing was studied from two aspects, the process of coal gas displacement by competitive adsorption and physical characteristics of fractured coal induced by phase transition. Crack propagation pattern in coal under different lateral coefficients was explored by using discrete-element numerical simulation software. Distribution characteristics of hoop stress of fractured coal were analyzed through theoretical calculation. The results show that: (1) Micro-cracks in damaged coal body generated during phase transition process are mainly crack_tension type, which are formed by the composite action of tension and compression. The crack propagation is the result of the continuous release of compressive stress from concentrated area to the surrounding units. Micro-cracks are radially distributed in a pattern of “flame”. (2) The main crack formed above the fracture hole grows in the direction of vertical minimum initial stress, and the main crack formed below the fracture hole develops in the direction of horizontal initial stress. As the lateral compression coefficient increases, the extension distance of the second crack will not change after reducing to a certain length. (3) As the distance from the fracture hole increases, the peak compression loaded at the monitoring point decays, and the loop stress in the cracked coal is distributed in a pattern of “peanut”. It provides practical methods and ideas for studying the macroscopic and microscopic development of cracks, as well as theoretical support for the on-site hole layout.

Deformation of Circular Tubes in Lateral Compression

1991 ◽  
Vol 51-52 ◽  
pp. 429-434
Author(s):  
H. Kobayashi ◽  
Masashi Daimaruya
Keyword(s):  
Lateral Compression ◽  
Circular Tubes

scholarly journals Objectivation of an Educational Model in Cranial Osteopathy Based on Experience

Medicina ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 246
Author(s):  
Jesús Requena-García ◽  
Evelyn García-Nieto ◽  
David Varillas-Delgado
Keyword(s):  
Scientific Evidence ◽  
Correlation Coefficients ◽  
Lateral Compression ◽  
Educational Model ◽  
Reliability Study ◽  
Intra Class Correlation ◽  
Observer Reliability ◽  
Fundamental Part ◽  
Manual Palpation ◽  
Base Of The Skull

Background and Objectives: The techniques directed to the cranial field in osteopathy are the most questioned due to the lack of scientific evidence. In osteopathic practice, manual palpation is essential and, therefore, measuring reliability is fundamental. The objective of this study is to assess the precision and objectification of an educational model in cranial osteopathy based on experience. Materials and Methods: A reliability study was conducted in a cadaver skull where a strain gauge was placed on the sphenobasilar synchondrosis (SBS) of the base of the skull. Three cranial osteopathic techniques (lateral compression, anteroposterior compression, and compression maneuver of the mastoids) were performed 25 times by osteopaths with different degrees of experience (5–10 years, 1–5 years, <1 year). Measurements were computed for each of the three techniques of each group in comparison with the osteopath with >15 years of experience. Data were analyzed to check for inter- and intra-observer reliability using intra-class correlation coefficients (ICC). Results: Reliability in osteopaths with 5–10 years’ experience (observer 1 and observer 2) performing all three techniques was higher (p < 0.001) than the osteopath with >15 years’ experience. Little or no reliability were observed in osteopaths with less experience. Conclusions: The experience of the osteopaths determines the reliability and effectiveness of the cranial techniques, a fundamental part in objectifying these techniques. This model can help implement objective training in cranial osteopathy formation.

Elastic-Plastic FEM Analysis of Deformations of a Cylinder Subjected to Severe Uniaxial and Bilateral Compression by Flat Plates

1991 ◽  
Author(s):  
M. Gotoh ◽  
Y. Shibata
Keyword(s):  
Compressive Force ◽  
Fem Analysis ◽  
Plane Stress State ◽  
Deformation Pattern ◽  
Lateral Compression ◽  
The Finite Element Method ◽  
Ring Plane ◽  
Flat Plates ◽  
Elastic Plastic ◽  
Plastic Forming

Abstract Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J2-flow theory (J2F), and J2-Gotoh’s corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming processes. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-tube forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square tube reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.

Lateral compression type I injuries of the pelvic ring: Are they mechanically stable?

Injury ◽  
2009 ◽  
Vol 40 (11) ◽  
pp. 1129-1130
Author(s):  
N.K. Kanakaris ◽  
C. Tzioupis ◽  
V.S. Nikolaou ◽  
P.V. Giannoudis
Keyword(s):  
Pelvic Ring ◽  
Type I ◽  
Lateral Compression ◽  
Compression Type
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