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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Biomechanical effects of multi-level laminoplasty and laminectomy: an experimental and finite element investigation

Kode, Swathi 01 December 2011 (has links)
Cervical spondylotic myelopathy is the most common spinal cord disorder in persons over 55 years of age in North America and perhaps in the world. Surgical options are broadly classified into two categories namely, anterior and posterior approaches. This study focuses on the posterior based approach (i.e. laminectomy or laminoplasty) which is considered when multiple levels of the spine have to be decompressed or when most of the cord compression results from posterior pathological conditions. The external and internal behavior of the spine after laminoplasty and laminectomy has been evaluated using both experimental and computational methods. Computationally, a validated intact 3D finite element model of the cervical spine (C2-T1) was modified to simulate laminectomy and laminoplasty (open door (ODL) and double door (DDL)) at levels C3-C6. During flexion, after ODL the adjacent levels C2-C3 and C6-C7 showed a 39% and 20% increase in the motion respectively; while no substantial changes were observed at the surgically altered levels. The percent increase in motion after DDL varied from 4.3% to 34.6%. The inclination towards increased motion during flexion after double door laminoplasty explains the role of the lamina-ligamentum flavum complex in the stability of spine. Compared to the intact model, laminectomy at C3-C6 led to a profound increase (37.5% to 79.6%) in motion across the levels C2-C3 to C6-C7. Furthermore, the changes in the von Mises stresses of the intervertebral disc observed after laminoplasty and laminectomy during flexion can be correlated to the changes in the intersegmental motions. An in-vitro biomechanical study was conducted to address the effects of laminoplasty (two-level and four-level) and four-level laminectomy on the flexibility of the cervical spine. Both two-level and four-level laminoplasty resulted in minimal changes in C2-T1 range of motion. For flexion/extension, two-level and multi-level laminoplasty showed an approximate 20% decrease (p>0.05) in the range of motion at C4-C5 and C2-C3 respectively due to the encroachment of the spinous process into the opened lamina. The decrease was mostly observed in older specimens and specimens with adjacent laminae close to each other; thus leading to the encroachment of the spinous process into the opened lamina. Laminectomy resulted in a statistically significant (p<0.05) increase in the range of motion compared to the intact condition during the three loading modes. These results correspond well with the finite element predictions, where a four-level ODL and laminectomy resulted in a minimal 5.4% and a substantial 57.5% increase in C2-T1 motion respectively during flexion. Adaptive bone remodeling theory was applied to the open door laminoplasty model to understand the effect of the surgical procedure on the internal architecture of bone. Bone remodeling was implemented at the C5 vertebra by quantifying the changes in apparent bone density in terms of the mechanical stimulus (i.e. SED/density). After laminoplasty, the increased load distribution through the bony hinge region led to the increased bone density during extension. This increased bone density could eventually lead to bone formation in those regions through external remodeling. The current study proved laminoplasty to be a motion preservation technique wherein the plates and spacer provided additional stability via reconstruction of the laminar arch while laminectomy can cause instability of spine especially during flexion. In the future, patient-specific finite element models that incorporate geometry-related differences could be developed to optimize the number of operated levels and to further explain the effect of surgical procedure on the unaltered levels.
282

Importância da ressonância magnética dinâmica da coluna cervical no tratamento da mielopatia espondilótica cervical / Importance of dynamic magnetic resonance of the cervical spine in the treatment of cervical spondylotic myelopathy

Ancheschi, Bruno da Costa 09 November 2018 (has links)
A mielopatia espondilótica cervical (MEC) é afecção relacionada diretamente com o estreitamento do canal vertebral cervical. O objetivo deste estudo foi avaliar variações morfométricas da coluna vertebral cervical em pacientes portadores de MEC por meio da ressonância magnética dinâmica nas posições neutra, em flexão e em extensão. Este é um estudo prospectivo de pacientes portadores de MEC secundária à doença degenerativa da coluna vertebral cervical. Os parâmetros morfométricos foram avaliados pelas sequências de ressonância magnética ponderadas em T2, no plano sagital em posições neutra, flexão e extensão. Os parâmetros estudados foram o comprimento anterior da medula espinhal (CAME), o comprimento posterior da medula espinhal (CPME), o diâmetro do canal vertebral (DCV) e o diâmetro da medula espinhal (DME). O CAME e o CPME foram mais longo em flexão do que nas posições em neutro e extensão, sendo encontrada diferença estatisticamente significativa entre a posição em flexão e extensão. O DCV e o DME foram maiores em flexão do que nas posições neutra e em extensão, no entanto não foi encontrada diferença estatisticamente significativa quando comparados nas posições em neutro, flexão e extensão. Desta forma, o exame de ressonância magnética dinâmica permite avaliar as variações morfométricas do canal vertebral cervical em pacientes portadores de mielopatia cervical espondilótica. / Cervical spondylotic myelopathy is a condition directly related to the narrowing of the cervical vertebral canal. The objective of this study was to evaluate morphometric variations of the cervical spine in patients with CSM using dynamic magnetic resonance imaging (MRI) in neutral, flexion and extension positions. This is a prospective study of patients with CSM secondary to degenerative disease of the cervical spine. The morphometric parameters were evaluated using T2-weighted MRI sequences in the sagittal plane with neutral, flexion and extension position of the neck. The parameters studied were the anterior length of the spinal cord (ALSC), the posterior length of the spinal cord (PLSC), the diameter of the vertebral canal (DVC) and the diameter of the spinal cord (DSC). The ALSC and PLSC were longer in flexion than extension and neutral position, with statistically significant difference between the flexion and extension position. The DVC and the DSC were greater in flexion than in extension and neutral position, however there was no statistically significant difference when comparing the positions in neutral, flexion and extension. Therefore, dynamic MRI allowed to evaluate morphometric variations in the cervical spinal canal in patients with cervical spondylotic myelopathy.
283

Stuburo kaklinės dalies tarpslankstelinių sąnarių išnirimų atstatymo optimizavimas / Optimization of reduction of facet dislocations of the lower cervical spine

Kontautas, Egidijus 07 December 2005 (has links)
1. INTRODUCTION Injuries of the lower cervical spine can be among the most devastating injuries of the musculoskeletal system because of the increased risk of the injury to the spinal cord, and also because they so often occur to the younger members of the population (Jones A.A.M. et al., 2003; Sekhon H.S.L. et al., 2001; Ball P.A., 2001). The cervical spine is the most vulnerable spinal segment (Sekhon H.S.L. et al., 2001). The mechanism of cervical spine trauma is defined by the direction and magnitude of the forces that have been applied externally to the head and neck complex resulting in injury (Allen B.L.Jr., 1982). Common injury vectors include flexion, compression, rotation and extension (Allen B.L.Jr., 1982). The pattern of injury is related not only to the external applied force, but also to the initial position or posture of the head and neck at the time of injury (Allen B.L.Jr., 1982). One pattern of these injuries of the lower cervical spine is a facet dislocations (Allen B.L.Jr., 1982). The facet dislocation of the cervical spine result from a hyperflexion injury of the neck (Allen B.L.Jr., 1982). These injuries are characterized radiographically by anterolisthesis of one cervical vertebrae over the other and include the slide anteriorly of the inferior facet of the upper dislocated vertebra over the superior facet of the vertebra below (Allen B.L.Jr., 1982; Razack N. et al., 2000). The facet dislocations of the lower cervical spine represent from 4% to 50% of... [to full text]
284

An epidemiological analysis of traumatic cervical spine fractures at a referral spinal unit : a three-month study

Singh, Natasha January 2008 (has links)
Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic Faculty: Health Sciences, Durban University of Technology, 2009 / Aim To determine the profile of traumatic cervical spine fractures with respect to the epidemiology, clinical presentation, types of fractures, conservative and surgical intervention, short-term post-intervention (i.e. post-conservative and post-surgical) complications and short-term post-surgical rehabilitation of patients presenting at the Spinal Unit of King George V Hospital over a 12-week period. Methods Patients who presented to the King George V Hospital Spinal Unit from surrounding hospitals with traumatic cervical spine fractures were evaluated by the medical staff. Data concerning the epidemiology, clinical presentation, types of fractures, conservative and surgical intervention, short-term post-intervention (i.e. post-conservative and postsurgical) complications and short-term post-surgical rehabilitation data were recorded by the researcher. A p-value of <0.05 was considered as statistically significant. Appropriate statistical tests were applied to the hypothesis-testing objectives. These involved the Pearson’s Chi Square Tests for categorical variables or Fisher’s Exact Tests as appropriate where sample sizes were small. Paired t-tests were done to compare preand- post-surgical Frankel grading and Norton Pressure Sore Assessment scores. Results The number of patients who presented to the Spinal Unit over a 12-week period was 20, of this number 17 were males, three were females and all were black. Eleven patients were treated surgically while nine patients were treated conservatively. The most frequent aetiology of cervical spine fractures was motor vehicle accidents (n = 10) followed by falls (n = 9). The most common co-existing medical conditions were smoking (n = 7), HIV (n = 5), alcohol abuse (n = 3) and obesity (n = 3). The most frequent locations of cervical spine fractures were C2 (n = 6), C1 (n = 4) and the posterior column of C6 (n = 3), while dislocations occurred primarily at the C5-C6 levels (n = 5) of the lower cervical spine. Odontoid fractures (n = 6), Jefferson’s fractures (n = 4) and unilateral facet dislocations (n = 6) were the most common fractures and dislocations v observed. Head injuries (n = 4) and lower limb fractures (n = 3) were the most common extra-spinal fractures. All subjects who sustained head injuries also had associated C1 or C2 fractures. Neurological complications most frequently involved the upper limb where loss of motor function (n = 8) and weakness (n = 4) were observed. The majority of the patients (n = 8) reported a Frankel Grading of E. There were no significant associations between types of fracture and gender with the exception of fracture/dislocation observed in two females. There was a statistically significant difference in the NPSA score (p = 0.004). Conservative care utilized included soft collar (n = 6), cones calipers (n = 6), physiotherapy (n = 4), Minerva jacket (n = 4) and SOMI (sterno-occipital mandibular immobilization) brace (n = 1) while surgical intervention included anterior decompression (n = 8), anterior fusion (n = 8), allograft strut (n = 8), discectomy (n = 8), anterior cervical plating (n = 8), anterior screw fixation (n = 2), a transoral approach (n = 1) and a corpectomy (n = 1). The short-term post-conservative care complications observed in this study were an occipital pressure sore (n = 1), severe discomfort (n = 1) as well as severe neck pain (n = 1), while the short-term post-surgical complications were severe neck pain (n = 2), oral thrush (n = 1), pneumonia (n = 1), odynophagia (n = 1) and hoarseness (n = 1). Of the 11 patients who underwent cervical spine surgery, ten were sent for physiotherapy and one for occupational therapy. No significant associations were seen between the type of cervical spine fracture and the age of the subject. There was a significant association between fracture/dislocation and the female gender (p = 0.016). There was significant negative association between odontoid fracture and: anterior decompression, anterior fusion, allograft strut, discectomy and anterior cervical plating (p = 0.006). Conclusion The results of this study reflect the presentation and management of cervical spine fractures at a referral spinal unit of a public hospital in KwaZulu Natal. The impact of HIV and other co-existing medical conditions were not determined due to the small sample size in this study. Further epidemiological studies are required to be conducted in the Spinal Units of all South African public hospitals in order to confirm or refute the observation of this study.
285

Genomic variation of human papillomavirus type 16 in relation to risk for high grade cervical and anal intraepithelial neoplasia /

Xi, Long Fu. January 1997 (has links)
Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [79]-87).
286

Impact of immunosuppression on the incidence and clearance of human papillomavirus in HIV-infected women in Alabama

Bhatta, Madhav P. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 13, 2008). Includes bibliographical references.
287

Relationship between cervical musculoskeletal impairments and temporomandibular disorders clinical and electromyographic variables /

Olivo, Susan Luz Armijo. January 2010 (has links)
Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Rehabilitation Science, Faculty of Rehabilitation Medicine. Title from pdf file main screen (viewed on April 30, 2010). Includes bibliographical references.
288

Recurso videocirúrgico para estudos de inseminação artificial transcervical em ovinos /

Taira, Augusto Ryonosuke January 2018 (has links)
Orientador: Wilter Ricardo Russiano Vicente / Resumo: RESUMO - O objetivo deste trabalho foi desenvolver um recurso videocirúrgico para inseminação artificial (IA) transcervical em ovinos. Foram utilizadas 30 ovelhas da raça Santa Inês com idades entre 2 a 5 anos todas pluríparas, divididas em três grupos experimentais: 1) IA por técnica convencional com tração cervical (GC); 2) IA por vídeo-vaginoscopia com insuflação (GVS) e; 3) IA videoassistida com fixação cervical (GVF). Durante o procedimento foi registrado o tipo do óstio cervical, número de anéis transpassados, local de deposição do sêmen no trato reprodutivo, tempo de manipulação cervical, taxa de passagem e fibrinogênio plasmáticos como marcador de reação inflamatória entre as técnicas. O diagnóstico gestacional foi realizado 21 dias após a inseminação artificial. Todos os dados foram submetidos a teste de normalidade seguido de um pós-teste, utilizando o programa estatístico R versão 3.2.5. Para o GVF a técnica não permitiu a entrada ao interior do útero com o aparelho, devido a ausência de expansão cervical associado à presença de muco no canal cervical, dificultaram a visualização. A insuflação da cavidade vaginal do GVS possibilitou a visualização da entrada do óstio cervical com facilidade, com a deposição do sêmen no interior do útero sem a fixação cervical em 10% dos animais (1/10). O número de anéis transpassados diferiu de acordo com o grupo experimental. Para o tempo de procedimento o GVF apresentou maior tempo de manipulação, quando comparado com os demais g... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
289

Rôle de l'environnement des spermatozoïdes de bélier dans leur transit dans le tractus génital femelle / Role of ram sperm environments during their transit through the female genital tract

Soleilhavoup, Clément 01 December 2015 (has links)
Chez les mammifères, les spermatozoïdes, au cours du transit à travers le tractus génital femelle, rencontrent des environnements qui influencent leur mobilité et leur pouvoir fécondant. L’analyse par spectrométrie de masse de ces milieux (plasma séminal, mucus cervical, fluides de l’utérus et de l’oviducte) a permis une caractérisation approfondie de leur protéome et l’identification de protéines modifiant l’activité des gamètes comme la Zinc Alpha Glycoprotein. L’étude du protéome du tractus génital femelle au cours du cycle oestral a montré une régulation différentielle de la sécrétion des protéines selon l’organe et le stade du cycle. La comparaison du protéome et des propriétés mécaniques du mucus cervical a montré l’impact de la mucine 5AC sur la viscosité du mucus et la mobilité des spermatozoïdes dans ce mucus. Cette interaction entre le mucus cervical et les spermatozoïdes se traduit par la fixation à leur surface de nouvelles protéines, comme la myosine 9, ayant un impact potentiel sur leur pouvoir fécondant. / During their transit through the female genital tract, mammalian spermatozoa encounter several environments that influence their mobility and fertilizing ability. Analysis by mass spectrometry of these environments (seminal plasma, cervical mucus, fluids from the uterus and the oviduct) enabled characterization of their proteomes and the identification of proteins able to modify gamete function such as Zinc Alpha Glycoprotein. The study of the female genital tract proteome during the oestrous cycle showed differential regulation of the protein secretion according to the organ and the stage of the cycle. Comparison of the proteome and the mechanical properties of cervical mucus showed the impact of mucin 5AC on the viscosity of mucus and the motility of spermatozoa in its presence. 52 cervical mucus proteins, such as myosin 9, bind to the surface of spermatozoa which may impact sperm function and fertilizing ability.
290

Influência da freqüência estimulatória envolvida nos efeitos analgésicos induzidos por eletroacupuntura em cervicalgia tensional / Sandra Mara Silvério Lopes ; orientador, Percy Nohama

Lopes, Sandra Mara Silvério January 2007 (has links)
Dissertação (mestrado) - Pontifícia Universidade Católica do Paraná, Curitiba, 2007 / Bibliografia: p. 73-83 / Acupuntura é uma técnica milenar que consiste na inserção de agulhas no corpo em locais especificamente definidos para fins terapêuticos. Com o avanço dos recursos tecnológicos associou-se a esta técnica estímulos elétricos originando a eletroacupuntura, / Acupuncture is a millenarian technique that consists of the insertion of needles inside the body in places specifically defined for therapeutically goals. With the progress of the technological resources, it was associated to nervous electrical stimulatio

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