• Title/Summary/Keyword: endplate

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Preoperative Gadolinium-enhanced Magnetic Resonance Images on Infectious Spondylitis

  • Kim, Seok-Won;Lee, Seung-Myoung;Shin, Ho
    • Journal of Korean Neurosurgical Society
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    • v.38 no.5
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    • pp.355-358
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    • 2005
  • Objective : The purpose of this study is to analyze the patterns of intervertebral disc enhancement seen in infectious spondylitis, differentiate between two groups[tuberculous vs pyogenic spondylitis]. Methods : Between January 1994 and December 2002, 83patients underwent operative procedure with confirmed to histopathologic evaluation. Magnetic resonance[MR] images were obtained in all patients and were analyzed retrospectively. 57patients had tuberculosis and 26patients were infected by pyogens. The patterns of gadolinium enhancement of disc were classified into 4 types[post's classification] : Type I, non-enhancing; Type II, enhancement of the peripheral rim; Type III, Type II with central area and partial endplate; Type IV, general enhancement. Results : The enhancement patterns observed were as follows : Common pattern of tuberculous spondylitis was Type II, and pyogenic spondylitis was Type III. [p < 0.01] This difference may result from pathophysiologic varieties of organisms. Conclusion : Careful preoperative MR analysis of the patterns of disc enhancement occuring in infectious spondylitis can be useful for differentiating between the tuberculous and pyogenic spondylitis.

Complete Separation of the Vertebral Body Associated with a Schmorl's Node Accompanying Severe Osteoporosis

  • Park, Seon Joo;Kim, Hyeun Sung;Kim, Hyun Sook;Kim, Seok Won
    • Journal of Korean Neurosurgical Society
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    • v.58 no.2
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    • pp.147-149
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    • 2015
  • A Schmorl's node is defined as a simple endplate intravertebral herniation resulting from trauma or idiopathic causes. Although Schmorl's nodes have been considered clinically insignificant, they might indicate an active symptomatic process or cause serious complications. In this study, we report an interesting case of complete separation of a vertebral body caused by an untreated Schmorl's node accompanying severe osteoporosis. To our knowledge, this is the first clinical report in the published literature to evaluate the complete separation of a vertebral body associated with a Schmorl's node.

Immunosuppressive Therapy for Autoimmune Myasthenia Gravis (자가면역 중증근무력증의 면역억제요법)

  • Kim, Su-Yeon;Hong, Yoon-Ho
    • Annals of Clinical Neurophysiology
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    • v.9 no.2
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    • pp.51-58
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    • 2007
  • Autoimmune myasthenia gravis (MG) is the neuromuscular junction disorder mostly caused by antibody against the acetylcholine receptor (AChR antibody) at the muscle endplate. The goal of treatment is to induce and maintain remission, i.e., absence of symptoms, with the least cost-to-benefit ratio. Although corticosteroids are effective in inducing remission in most patients, they have numerous potentially serious adverse effects with their long-term use. In addition, some patients do not respond or are intolerant to the conventional treatment. In this article, we discuss the difficulties encountered in long-term immunosuppressive treatment of MG, and review useful tips for the use of corticosteroids. Long-term immunosuppressive agents that can be used in steroid-refractory or -dependent patients will be reviewed with their safety profiles and efficacy in MG.

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Load Sharing Mechanism Across Graft-Bone Interface in Static Cervical Locking Plate Fixation

  • Han, In-Ho;Kuh, Sung-Uk;Chin, Dong-Kyu;Jin, Byung-Ho;Cho, Yang-Eun;Kim, Keun-Su
    • Journal of Korean Neurosurgical Society
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    • v.45 no.4
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    • pp.213-218
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    • 2009
  • Objective : This study is a retrospective clinical study over more than 4 years of follow up to understand the mechanism of load sharing across the graft-bone interface in the static locking plate (SLP) fixation compared with non-locking plate (NLP). Methods : Orion locking plates and Top non-locking plates were used for SLP fixation in 29 patients and NLP fixation in 24 patients, respectively. Successful interbody fusion was estimated by dynamic X-ray films. The checking parameters were as follows : screw angle (SA) between upper and lower screw, anterior and posterior height of fusion segment between upper and lower endplate (AH & PH), and upper and lower distance from vertebral endplate to the end of plate (UD & LD). Each follow-up value of AH and PH were compared to initial values. Contributions of upper and lower collapse to whole segment collapse were estimated. Results : Successful intervertebral bone fusion rate was 100% in the SLP group and 92% in the NLP group. The follow-up mean value of SA in SLP group was not significantly changed compared with initial value, but follow-up mean value of SA in NLP group decreased more than those in SLP group (p=0.0067). Statistical analysis did not show a significant difference in the change in AH and PH between SLP and NLP groups (p>0.05). Follow-up AH of NLP group showed more collapse than PH of same group (p=0.04). The upper portion of the vertebral body collapsed more than the lower portion in the SLP fixation (p=0.00058). Conclusion : The fused segments with SLP had successful bone fusion without change in initial screw angle, which was not observed in NLP fixation. It suggests that there was enough load sharing across bone-graft interface in SLP fixation.

Analytical and Experimental Study of an Unstiffened Extended End-Plate Connection (반복하중을 받는 비보강 확장 단부판 접합부의 해석 및 실험적 연구)

  • Kim, Hee Dong;Yang, Jae Guen;Pae, Da Sol
    • Journal of Korean Society of Steel Construction
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    • v.28 no.6
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    • pp.439-448
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    • 2016
  • Extended end-plate connections(EEPC) are a type of connection applied in Pre-Engineered Building structures comprising beam-column connections of steel structures or tapered members. Extended end-plate connections(EEPC) show different behavioral characteristics owing to the influence of plate thickness, gauge distance of high strength bolt, diameter of high strength bolt frame, and the number of high strength bolts. In the USA and Europe, extended end-plate connections(EEPC) are applied in beam-column connections of steel structures in various forms; however, these are not widely applied in structures in Korea.This can be attributed to the fact that the proposal of design strength types for extended end-plate connections(EEPC), proposal of connection specifications, evaluation of seismic performance, and are not being performed appropriately. Therefore, the purpose of this study is to provide basic data for the domestic application of Unstiffened extended endplate connections. To realize this, nonlinear finite element analysis was conducted on a 12-mm thick Unstiffened extended endplate connections.

Association between Prognosis of Low Back Pain Patients with Severity of Abnormal Lumbar Lordosis (한방병원에 입원한 요통 환자의 요추 전만각, 요천각 변화의 심각도에 따른 예후 분석 연구)

  • Han, Su-Bin;Kim, Eun-San;Kim, Hyo-Jun;Jo, Hoo-In;Kim, Mi-hye;Lee, Nam-Woo;Han, Jeong-Hun;Park, Byung-Hak;Son, Jae-Min;Kang, Do-Hyeon;Min, Tae-Woon;Lee, Hyun-Jun;Ahn, Jae-Seo;Lee, Han-Sol
    • Journal of Korean Medicine Rehabilitation
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    • v.30 no.4
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    • pp.143-154
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    • 2020
  • Objectives To analyze the prognosis of patients with low back pain according to the severity of abnormal lumbar lordotic angle and Ferguson's angle. Methods Data from electronic medical record of a total of 199 patients hospitalized in Korean medicine hospital were analyzed. With the sagittal view of lumbar spine X-ray, lumbar lordotic angle was defined as the angle between the superior endplate of L1 with the inferior endplate of L5. Ferguson's angle was defined as the angle between the superior surfaces of the sacral with a horizontal line. 'Measure Cobb's Angle Tool' of 'INFINITT PACS' was used to measure both angles. Lumbar lordotic angle and Ferguson's angle were subdivided into five sections. The number of days from onset and the duration of hospitalization were analyzed in each section. Results Severe hypolordotic lumbar lordotic angle group were found to have longer medical history and hospitalization duration than the control group. The ratio of long-term hospitalization (over 15 days) and chronic medical history (over 180 days) of patients with severe hypolordotic Ferguson's angle were significantly higher than the control group. The ratio of patients with chronic medical history (over 180 days) was significantly higher in severe hyperlordotic Ferguson's angle group than the control group. Conclusions Severe hypolordotic lumbar lordotic angle was related to patient's prognosis. Both severe hyperlordotic and severe hypolordotic Ferguson's angle were found to be related to patient's prognosis. However, a moderate loss of lumbar lordotic angle and Ferguson's angle was not related to prognosis of low back pain patients.

Effect of the Radius of Curvature on the Contact Pressure Applied to the Endplate of the Sliding Core in an Artificial Intervertebral Disc (인공추간판 슬라이딩 코어의 곡률반경 변화가 종판의 접촉압력에 미치는 영향)

  • Kim, Cheol-Woong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.1
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    • pp.29-35
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    • 2012
  • The treatments for spinal canal stenosis are radicular cyst removal, spine fusion, and implantation of an artificial intervertebral disc. Artificial intervertebral discs have been most widely used since the mid-2000s. The study of artificial intervertebral discs has been focused on the analysis of the axial rotation, lateral bending, the degrees of freedom of the disc, and flexion-extension of the vertebral body. The issue of fatigue failure years after the surgery has arisen as a new problem. Hence, study of artificial intervertebral discs must be focused on the fatigue failure properties and increased durability of the sliding core. A finite element model based on an in the artificial intervertebral disc (SB Charit$\acute{e}$ III) was produced, and the influence of the radius of curvature and the change in the coefficient of friction of the sliding core on the von-Mises stress and contact pressure was evaluated. Based on the results, new artificial intervertebral disc models (Models-I, -II, and -III) were proposed, and the fatigue failure behavior of the sliding core after a certain period of time was compared with the results for SB Charit$\acute{e}$ III.

Diurnal Variation in Hydration of the Cervical Intervertebral Disc Assessed Using T2 Mapping of Magnetic Resonance Imaging

  • Chanyuan Liu;Jingyi Wang;Bowen Hou;Yitong Li;John N. Morelli;Peisen Zhang;Jun Ran;Xiaoming Li
    • Korean Journal of Radiology
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    • v.23 no.6
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    • pp.638-648
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    • 2022
  • Objective: The study aimed to investigate the diurnal variation in cervical disc hydration and its relationship with cervical degeneration. Materials and Methods: C3-C7 discs of 86 prospectively enrolled participants (37 males, 49 females; mean age ± standard deviation, 23.5 ± 2.5 years) were assessed using T2 mapping in the morning and evening. All discs were stratified by Miyazaki grade or C2-C7 Cobb angle and T2 values (T2). The degree of diurnal T2 variation (T2-DDV), defined as (morning T2 - evening T2)/morning T2 x 100%, was measured for the entire disc, annulus fibrosus (AF), nucleus pulposus (NP), and endplate zones. Results: T2 of the entire disc decreased significantly after the daytime load (p < 0.001), with a T2-DDV of 13.3% for all discs and 16.0%, 12.2%, and 13.0% for healthy (grade I), mild degenerative (grade II), and advanced degenerative (grade III/IV) discs, respectively. T2 of regional NPs and AFs decreased significantly from morning to evening (p ≤ 0.049) except in the healthy anterior inner AF (p = 0.092). Compared with healthy discs, mild degenerative discs displayed lower T2 and T2-DDV in regional NPs (p < 0.001). Advanced degenerative discs showed higher T2-DDV in the anterior inner AF compared with healthy discs (p = 0.050). Significant diurnal T2 changes in the endplate zones were observed only in healthy discs (p = 0.013). Cervical discs in the low Cobb angle group showed higher T2-DDV in the anterior AFs and anterior NP and lower T2-DDV in the posterior AF than those in the high Cobb angle group (p ≤ 0.041). Conclusion: This study characterized the diurnal variation in hydration of the cervical discs as assessed using T2 mapping and revealed early chemo-mechanical coupling dysfunction in degenerating discs. Cervical sagittal alignment on MRI can affect the diurnal stress patterns of the cervical discs. T2 mapping is sensitive to disc biomechanical dysfunction and offers translational potential from biomechanical research to clinical application.

Progressive collapse analysis of stainless steel composite frames with beam-to-column endplate connections

  • Wang, Jia;Uy, Brian;Li, Dongxu;Song, Yuchen
    • Steel and Composite Structures
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    • v.36 no.4
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    • pp.427-446
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    • 2020
  • This paper carries out the progressive collapse analysis of stainless steel composite beam-to-column joint sub-models and moment-resisting frames under column removal scenarios. The static flexural response of composite joint sub-models with damaged columns was initially explored via finite element methods, which was validated by independent experimental results and discussed in terms of moment-rotation relationships, plastic hinge behaviour and catenary actions. Simplified finite element methods were then proposed and applied to the frame analysis which aimed to elaborate the progressive collapse response at the frame level. Nonlinear static and dynamic analysis were employed to evaluate the dynamic increase factor (DIF) for stainless steel composite frames. The results suggest that the catenary action effect plays an important role in preventing the damaged structure from dramatic collapse. The beam-to-column joints could be critical components that influence the capacity of composite frames and dominate the determination of dynamic increase factor. The current design guidance is non-conservative to provide proper DIF for stainless steel composite frames, and thus new DIF curves are expected to be proposed.

Steady Aerodynamic Characteristics of FAST Flying over Nonplanar Ground Surface (비평면 지면을 비행하는 FAST의 정상상태 공력특성)

  • Cho, Yeon-Woo;Cho, Jeong-Hyun;Cho, Jin-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.6
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    • pp.483-488
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    • 2007
  • The aerodynamic characteristics of FAST(Future Air Speed Transit) combined the body with tandem wing flying over nonplanar ground surface are investigated by using a boundary element method. To validate the present method, results of the present analysis are compared with the experiment and other numerical results. The arrangement of the tandem wing is determined to secure sufficient aero-levitation force and the stability through the analysis of the aerodynamic characteristics of the FAST. The FAST has the maximum lift characteristics when the tandem wing with lower endplate is located at the front side and the rear side of the body. The stability of the FAST can be secured by using the flaperon of the tandem wing.