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排序方式: 共有621条查询结果,搜索用时 421 毫秒
1.
2.
寰枢椎后路二种内固定技术的三维稳定性评价 总被引:3,自引:0,他引:3
目的:对比寰枢椎椎弓根螺钉固定系统与枢椎椎弓根螺钉联合寰椎椎板钩固定系统的生物力学稳定性,为临床应用提供实验依据。方法:新鲜颈椎标本6例,损伤齿突基底部,建立寰枢椎失稳模型,在脊柱三维运动实验机上先测量失稳寰枢椎的三维运动范围,再在失稳模型上对每具标本进行两种内固定:C1椎弓根螺钉 C2椎弓根螺钉的钉棒内固定系统,C1椎板钩 C2椎弓根螺钉的钉棒钩内固定系统,测量二种不同固定方法的寰枢椎三维运动范围,比较两种状态下的寰枢椎稳定状况。结果:C1椎弓根螺钉 C2椎弓根螺钉的钉棒内固定与C1椎板钩 C2椎弓根螺钉的前屈、后伸、左右侧屈无显著性差异,左右旋转C1椎弓根螺钉组优于C1椎板钩组。结论:两种寰枢固定方法:C1椎弓根螺钉 C2椎弓根螺钉固定系统在抗左右旋转方面较C1椎板钩 C2椎弓根螺钉固定系统的稳定性优越,临床上应优先选择C1、C2椎弓根螺钉固定方法,当C1椎弓根过于细小时可选用C1椎板钩 C2椎弓根螺钉的固定技术。 相似文献
3.
Christopher J. Percival Jay Devine Benjamin C. Darwin Wei Liu Matthijs van Eede R. Mark Henkelman Benedikt Hallgrimsson 《Journal of anatomy》2019,234(6):917-935
Morphometric analysis of anatomical landmarks allows researchers to identify specific morphological differences between natural populations or experimental groups, but manually identifying landmarks is time‐consuming. We compare manually and automatically generated adult mouse skull landmarks and subsequent morphometric analyses to elucidate how switching from manual to automated landmarking will impact morphometric analysis results for large mouse (Mus musculus) samples (n = 1205) that represent a wide range of ‘normal’ phenotypic variation (62 genotypes). Other studies have suggested that the use of automated landmarking methods is feasible, but this study is the first to compare the utility of current automated approaches to manual landmarking for a large dataset that allows the quantification of intra‐ and inter‐strain variation. With this unique sample, we investigated how switching to a non‐linear image registration‐based automated landmarking method impacts estimated differences in genotype mean shape and shape variance‐covariance structure. In addition, we tested whether an initial registration of specimen images to genotype‐specific averages improves automatic landmark identification accuracy. Our results indicated that automated landmark placement was significantly different than manual landmark placement but that estimated skull shape covariation was correlated across methods. The addition of a preliminary genotype‐specific registration step as part of a two‐level procedure did not substantially improve on the accuracy of one‐level automatic landmark placement. The landmarks with the lowest automatic landmark accuracy are found in locations with poor image registration alignment. The most serious outliers within morphometric analysis of automated landmarks displayed instances of stochastic image registration error that are likely representative of errors common when applying image registration methods to micro‐computed tomography datasets that were initially collected with manual landmarking in mind. Additional efforts during specimen preparation and image acquisition can help reduce the number of registration errors and improve registration results. A reduction in skull shape variance estimates were noted for automated landmarking methods compared with manual landmarking. This partially reflects an underestimation of more extreme genotype shapes and loss of biological signal, but largely represents the fact that automated methods do not suffer from intra‐observer landmarking error. For appropriate samples and research questions, our image registration‐based automated landmarking method can eliminate the time required for manual landmarking and have a similar power to identify shape differences between inbred mouse genotypes. 相似文献
4.
A standard atlas space with stereotaxic co-ordinates for the postnatal day 0 (P0) C57BL/6J mouse brain was constructed from
the average of eight individual co-registered MR image volumes. Accuracy of registration and morphometric variations in structures
between subjects were analyzed statistically. We also applied this atlas coordinate system to data acquired using different
imaging protocols as well as to a high-resolution histological atlas obtained from separate animals. Mapping accuracy in the
atlas space was examined to determine the applicability of this atlas framework. The results show that the atlas space defined
here provides a stable framework for image registration for P0 normal mouse brains. With an appropriate feature-based co-registration
strategy, the probability atlas can also provide an accurate anatomical map for images acquired using invasive imaging methods.
The atlas templates and the probability map of the anatomical labels are available at . 相似文献
5.
C. Sorlié O. Bertrand B. Yvert J. -C. Froment J. Pernier 《Medical & biological engineering & computing》1997,35(3):239-245
A method has been developed to match a standard digitised brain atlas onto MR images for identification of cerebral structures
in anatomical images. This method uses, first, a three-dimensional crude registration based on the proportional system of
Talairach. Then, a two-dimensional refined registration is performed using a deformation function based on a set of homologous
landmarks on both images (MR and atlas). Displacements vectors are computed between each corresponding landmark. These vectors
are interpolated by thin-plate splines, generating an unwarping function defined on the whole image. This function can then
be applied on any structure of the atlas. An evaluation of the matching procedure has been performed. First, the influence
of the choice of the landmarks has been evaluated for the fine registration method. The latter has been then compared to the
crude registration method considered as a classical reference method. These results show the advantages of the fine registration
approach. 相似文献
6.
目的:探讨寰椎后弓半切除在高位上颈椎哑铃状神经鞘瘤手术的可行性及临床疗效。方法:回顾性分析2005年1月至2018年12月高位上颈椎哑铃状神经鞘瘤患者13例,男10例,女3例;年龄19~67岁;枕骨大孔至C1平面4例,C1,2平面9例。进行寰椎后弓半切除摘除肿瘤,未内固定,临床疗效采用疼痛视觉模拟评分(visual analogue scale,VAS),日本骨科协会(Japanese Orthopaedic Association,JOA)评分及美国脊髓损伤学会(American Spinal Injury Association,ASIA)分级等进行比较。结果:13例均顺利完成手术,术中均未出现椎动脉损伤及脊髓损伤。13例均随访12个月以上,未发现局部复发,VAS评分及JOA评分均较术前改善。术前ASIA分级:C级1例,D级6例,E级6例;末次随访D级3例,E级10例。结论:寰椎后弓半切除可Ⅰ期切除高位上颈椎哑铃状神经鞘瘤,短期临床疗效好,无颈椎不稳等并发症。 相似文献
7.
Aromatic L-amino acid decarboxylase-immunohistochemistry in the cat lower brainstem and midbrain 总被引:1,自引:0,他引:1
K Kitahama M Denoyer B Raynaud C Borri-Voltattorni M Weber M Jouvet 《The Journal of comparative neurology》1990,302(4):935-953
By indirect immunohistochemistry, the present study examined the distribution of neuronal structures in the cat medulla oblongata, pons, and midbrain, showing immunoreactivity to aromatic L-amino acid decarboxylase (AADC), which catalyzes the conversion of L-3, 4-dihydroxyphenylalanine (L-DOPA) to dopamine, and 5-hydroxytryptophan to serotonin (5HT). With simultaneous and serial double immunostaining techniques, immunoreactivity to this enzyme was demonstrated in most of the catecholaminergic and serotonergic neurons. We could also demonstrate AADC-IR cell bodies that do not contain tyrosine hydroxylase (TH-) or 5HT-immunoreactivity (called "D-type cells") outside such monoaminergic cell systems. At the medullo-spinal junction, very small D-type cells were found within and beneath the ependymal layer of the 10th area of Rexed surrounding the central canal. D-type cells were localized in the caudal reticular formation, nucleus of the solitary tract, a dorsal aspect of the lateral parabrachial nucleus, and pretectal areas as have been reported in the rat. Furthermore, the present study describes, in the cat brainstem, new additional D-type cell groups that have not been reported in the rat. Dense or loose clusters of D-type cells were localized in the external edge of the laminar trigeminal nucleus, dorsal motor nucleus of the vagus, external cuneate nucleus, nucleus praepositus hypoglossi, central, pontine, and periaqueductal gray, superficial layer of the superior colliculus, and area medial to the retroflexus. D-type cells were loosely clustered in the lateral part of the central tegmental field dorsal to the substantia nigra, extending dorsally in the medial division of the posterior complex of the thalamus and medial side of the brachium of the inferior colliculus. They extended farther rostrodorsally along the medial side of the nucleus limitans and joined with the pretectal cell group. Almost all these cells were very small and ovoid to round with 1-2 short processes with the exception of dorsal motor vagal cells. AADC-IR axons were clearly identified in the vagal efferent nerves, longitudinal medullary pathway, dorsal tegmental bundle rostral to the locus coeruleus. Serotonergic axons were identified not only in the central tegmentum field and lateral side of the central superior nucleus, but also in the ventral surface of the medulla oblongata. We describe principal densely stained fiber plexuses in the cat brainstem. The findings of the present study provide a morphological basis for neurons that decarboxylate endogenous and exogenous L-DOPA, 5HTP, and other aromatic L-amino acids. 相似文献
8.
[目的]通过10名中医师对230例舌图中舌色诊断结果的分析,探讨并分析不同中医师对观察结果一致性的影响.[方法]让10名中医师在自然光线下,对舌色较为典型、印刷质量较高的230副舌图进行观察并填写舌色观察表,判断结果一致率采用百分比表示.[结果]从舌色诊断结果的分析看出:1)舌诊具体内容丰富,观察结果离散性较大,舌象的复杂性与模糊性使传统的望舌方法难以客观地描述某一舌象.2)不同的中医师因为其视觉生理、知识水平,经验以及语言习惯等因素影响,对同一舌图有不同的判断结果,这样难以准确地判断舌象.[结论]中医需要寻求更客观的方式来诠释舌色的内容,从而减少因为各种原因引起的舌色判别结果的不一致性.所以在传统辨舌的基础上,建立标准舌色样本库以及自动识别系统有重要意义和价值. 相似文献
9.
目的:探讨脑电地形图在癫癎病人中的应用价值。方法:脑电地形图在132例原发性癫癎和18例继发性癫癎病人中被检查了。结果:在这些病人中脑电地形图的改变是明显的。结论:脑电地形图在癫癎诊断和鉴别诊断中有重要的应用价值。 相似文献
10.
Ctenophora is an early-branching basal metazoan lineage, which may have evolved neurons and muscles independently from other animals. However, despite the profound diversity among ctenophores, basal neuroanatomical data are limited to representatives of two genera. Here, we describe the organization of neuromuscular systems in eight ctenophore species focusing on Euplokamis dunlapae—the representative of the lineage sister to all other ctenophores. Cydippids (Hormiphora hormiphora and Dryodora glandiformis) and lobates (Bolinopsis infundibulum and Mnemiopsis leidyi) were used as reference platforms to cover both morphological and ecological diversity within the phylum. We show that even with substantial environmental differences, the basal organization of neural systems is conserved among ctenophores. In all species, we detected two distributed neuronal subsystems: the subepithelial polygonal network and the mesogleal elements. Nevertheless, each species developed specific innovations in neural, muscular, and receptor systems. Most notable Euplokamis-specific features are the following: (a) Comb nerves with giant axons. These nerves directly coordinate the rapid escape response bypassing the central integrative structure known as the aboral sensory organ. (b) Neural processes in tentacles along the rows of “boxes” providing structural support and located under striated muscles. (c) Radial muscles that cross the mesoglea and connect the outer wall to the aboral canal. (d) Flat muscles, encircling each meridional canal. Also, we detected a structurally different rectangular neural network in the feeding lobes of Lobata (Mnemiopsis/Bolinopsis) but not in other species. The described lineage-specific innovations can be used for future single-cell atlases of ctenophores and analyses of neuronal evolution in basal metazoans. 相似文献