颈部钝伤齿突侧块间隙不对称CT扫描的价值

目的 :研究颈部钝伤齿突侧块间隙 (LADS)不对称患者功能位CT扫描时寰枢椎旋转角度 ,为临床有关疾病的诊断治疗提供帮助。方法 :3 0例正常人和 2 5例患者行中立位CT扫描 ,然后行左、右旋转 2 5°～ 45°功能位扫描 ,测量功能位寰枢椎相对旋转角度。结果 :3 0例正常人寰椎相对于枢椎的旋转角度大于 8°。 2 5例受伤者中 19例寰椎相对于枢椎的旋转角度大于 8° ,其余 1周后CT复查均大于 8° ,枢椎的运动弧度正常时应小于寰椎的 5 0 %。结论 :张口位平片显示LADS间隙不对称而临床无其他症状者无需进一步检查或治疗。而临床伴有旋转固定症状者 ,需用功能位CT扫描。     

正常人寰枢关节间隙的CT研究

目的研究正常人寰枢关节CT图像关节间隙大小及功能位置间隙变化情况,并对相关因素进行探讨.方法120例正常人行中立位CT扫描,66例行冠状矢状位重建,56例行头颅左、右旋各15～25°扫描,30例行侧曲及屈、伸位扫描,56例均摄取中立位及左、右旋转位15～25°X线片.测量CT片寰齿间隙值,观察功能位间隙变化.结果寰齿前间隙(ADI)值在不同年龄阶段存在差异.齿突与环椎侧块间隙(LADS),青年儿童组两侧不对称比例及程度高于成人,间隙不对称者寰枢椎发育异常所占比例较高.发现寰枕间存在相对旋转者28例.头颅左、右旋转位,42.86%受检者旋转同侧LADS变窄,57.14%无明显改变与平片结果不同.结论CT扫描对于显示寰枢区结构有X线平片无可比拟的优越性,X线平片旋转位间隙变化不同于CT扫描.     

寰枢关节旋转脱位的CT诊断

目的　研究寰枢关节旋转脱位的CT表现并探索其诊断价值。方法　 3 6例寰枢关节旋转脱位患者行CT扫描 ,9例同时行平片侧位或张口位检查 ;6例正常人行功能性CT扫描。结果　 3 6例寰枢关节旋转脱位CT均可清晰显示寰枢椎间固定角度及寰椎移位、寰枢椎骨折、骨性椎管的形态及周围病变等。平片不能显示寰枢椎之间的旋转情况。正常人寰枢关节可向左右旋转 3 3°～60°。结论　CT可以清晰显示寰枢椎之间旋转情况 ,而寰枢之间旋转固定是诊断寰枢关节旋转脱位的重要基础     

寰枢关节脱位的影像诊断

寰枢椎脱位是较为常见的上颈部创伤,若不及时诊断治疗常进行性加重,压迫颈髓危及生命。日常工作中常因对寰枢椎旋转脱位影像特征认识不足而导致误诊、漏诊,延误治疗。鉴于此,从齿突距寰椎两侧块间距(寰齿间距),双寰椎侧块冠状面形态、大小,双侧寰枢椎侧块间隙,双侧侧块上下关节面关系及齿突距寰椎前结节间距(寰齿前间隙)等5方面分析寰枢椎相对关系,准确认识寰枢椎正常中立静止状态、相对水平移动、正常旋转时X线及CT表现,以及寰枢椎各类型脱位时X线及CT特征,提高诊断准确率。     

寰枢脱位时寰椎的偏斜与旋转

枢椎完整的寰枢脱位 (ＡＡＤ) ,齿突并不都位于寰椎前结节的正后方并均匀一致地压迫延髓、脊髓。为此 ,笔者复习了 2 3例难复性ＡＡＤ的临床资料 ,发现 7例有寰椎的偏斜和旋转 ,影像学上表现为齿突偏于寰椎段椎管的一侧。现报告如下。临　床　资　料1.本组共 7例 ,一般资料见表 1。2 .影像学表现 :本组 7例均具有寰椎前脱位的影像学特征 ,即寰齿间隙 (寰椎枕化时则称斜坡齿突间隙 )增大。但齿突与枢椎体相连 (即枢椎完整 ) ,同时又有齿突偏移和旋转的影像学表现。4例ＡＡＤ有寰椎偏移 (例 1～ 4 ) ,其中 1例单纯性ＡＡＤ (例 1)寰齿间距6ｍ…     

关于颈枢椎齿突偏移是否为脱位的再认识

迄今，在颈椎枕寰枢关节脱位的诊断上，存在一个突出问题，这就是：“齿突偏移，与寰椎侧块左右间距不对称”被认为是寰枢关节脱位。由于认识分歧，以致临床处理混乱，有的患者更被做了寰枢椎融合手术，医患纠纷频发。对“齿突偏移”的征象，认识分歧由来已久。国外早期一些专著曾把“齿突偏移”视为寰枢侧方脱位。陈学仁等”。在国内最早把“齿突与侧块间隙左右不对称”作为寰枢侧方脱位的主要诊断标准。最近，张仁元提出：齿突偏移，寰椎滑移，枢椎关节面左右不等宽，枢椎棘突偏歪等8项指标是枢椎旋转半脱位和枢椎侧方脱位的诊断指征。Shapiro等注意到这现象出现于动态变化过程中，并不认为是寰枢脱位。Rothman等并没有把“齿突偏移”视为寰枢椎侧方脱位的诊断指征。上述分歧，究其根源，主要是对寰枢关节的特殊功能结构和动态变化的认识问题。因此，有必要对此问题进行重新再认识。     

三维CT成像在小儿寰枢椎旋转性移位中的应用

目的　探讨三维CT成像 ( 3DCT)对小儿寰枢椎旋转性移位 (atlanto axialrotatorydisplacement,AARD)的诊断价值。材料与方法　分析和比较 6例小儿AARD在普通CT扫描 ( 2DCT)和 3DCT中的影像表现。结果　 ( 1) 2DCT和 3DCT测量 6例患儿寰齿前间距和齿状突侧距的结果基本相同 ;( 2 ) 3DCT显示 6例患儿侧块均有不同程度的移位和旋转 ,2DCT不能显示侧块有无移位和旋转 ;( 3) 6例中 ,2DCT显示 1例同时有寰椎 (C1)和枢椎 (C2 )的异常旋转 (分别为 8°和 35°) ,3例有C2 异常旋转 ( 7°～ 30° ,平均 18.7°) ,2例未发现寰枢椎的旋转异常。 3DCT显示 2例同时有C1和C2 旋转异常 (分别为 11°、30°和 11°、40°) ,4例有C2 旋转异常 ( 9°～ 34° ,平均 16 .5°)。相同病例 ,2DCT对C1和C2 旋转程度的测量低于 3DCT所测得的结果 ;( 4 ) 3DCT发现 1例齿状突发育不良 ,表现为齿状突短平和齿突尖消失 ,2DCT不能观察齿状突的发育状况。结论　 3DCT对AARD的诊断作用明显优于 2DCT。 3DCT不仅能准确地、直观地评估齿状突和侧块的移位程度、方向以及寰枢椎的旋转程度 ,而且能发现伴发的寰枢椎尤其是齿状突发育畸形 ,对全面明确AARD诊断和指导治疗具有重要意义     

寰枢关节齿突侧块间隙的多层螺旋CT研究

目的 探讨寰枢关节齿突侧块间隙(LADI)的影像特征及其在寰枢关节病变诊断中的意义.方法 240名无寰枢关节病变的健康志愿者和32例临床确诊的寰枢关节脱位或半脱位患者分别行中立位和左右旋转功能位CT扫描,观察其LADI的影像表现,并对左右LADI和双侧齿突侧块间距差(VBLADI)进行测量和对照分析.正常对照组各年龄男女组间双侧LADI不对称阳性率比较用x2检验,正常对照组VBLADI与寰枢椎旋转功能相关性的判定用Pearson双侧检验,正常对照组与病变组比较用四格表精确检验法.结果 (1)正常对照组:240名志愿者双侧LADI不对称的发生率为85.00%(204/240);＜15岁年龄组60名,|VBLADI|中位数为0.850 mm,95%百分位数(P95%)=2.450 mm,＞2.450 mm 者2名;≥15岁年龄组180名,|VBLADI|中位数0.700 mm,P95%=2.051 mm,＞2.051 mm 者10名.VBLADI(-2.146～2.114 mm,中位数0.000 mm)与寰枢椎相对左旋角度(LA:22.949°～44.649°,中位数34.500°)、右旋角度(RA:25.284°～45.334°,中位数35.300°)、左右旋角度差(VLRA:-11.643°～8.623°,中位数0.000°)没有相关性(r=-0.030、-0.005、0.026,P值均＞0.05).(2)病例组:32例患者中,＜15岁者25例,≥15岁者7例.寰枢关节侧方半脱位(AALSD)17例,其中＜15岁者16例,|VBLADI|中位数为3.350 mm,＞2.450 mm者14例,≥15岁者1例|VBLADI|≥2.051 mm.寰枢关节旋转脱位(AARD)7例,其中4例＜15岁者|VBLADI|均＜2.450 mm,中位数为1.200 mm,3例≥15岁者| VBLADI |均＜2.051 mm,7例AARD均显示一侧LADI呈伞形.寰枢关节复合脱位(AACD)8例,其中5例＜15岁者＞2.450 mm者4例,成人3例| VBLADI |均≥2.051 mm.AALSD组和AACD组|VBLADI|≥P95%者多于正常组,差异有统计学意义(P均＜0.01),AARD组与正常组间差异无统计学意义(P=0.738).结论 双侧LADI不对称既可见于正常人,也可能是一种病理状态,应结合临床表现和其他影像征象综合分析.     

后正中入路齿状突截骨治疗齿状突骨折畸形愈合致不可复性寰枢椎脱位4例

齿状突骨折畸形愈合致不可复性寰枢椎脱位临床上较为少见, 可引起患者头颈疼痛、活动受限、脊髓压迫及神经损害症状。传统治疗策略为前路经口咽或下颌下入路切断齿状突畸形愈合部分, 再经前路或后路进行寰枢椎复位固定融合, 存在经口咽Ⅱ类切口易感染、前后联合入路相关手术风险增加、学习曲线陡峭等不足。后侧方入路可经寰枢侧块关节抵达齿状突, 但不便于处理双侧寰枢侧块关节间隙及内固定置入操作, 而后正中入路相对显露简便、易于掌握。为此, 笔者采用回顾性病例系列研究分析2018年9月至2021年9月兰州大学第二医院收治的4例齿状突骨折畸形愈合致不可复性寰枢椎脱位患者临床资料, 探讨后正中入路齿状突截骨治疗的效果。     

镁合金与钛合金经口咽前路寰枢椎复位内固定钢板治疗寰枢椎脱位的三维有限元分析

目的 应用三维有限元分析评价镁合金与钛合金制备的经口咽前路寰枢椎复位内固定钢板(transoralpharyngeal atlantoaxial reduction plate,TARP)系统治疗寰枢椎脱位后的生物力学性能,测试镁合金材料制备TARP系统的可行性,为临床手术治疗提供理论依据. 方法 选择1例典型寰枢椎骨折脱位患者,并与临床已经应用的钛合金材料制备的TARP系统进行CT薄层扫描,获得DICOM图像数据.导入三维有限元分析软件,分别模拟使用钛合金与镁合金两种不同材料制备TARP系统进行复位与内固定,应用三维有限元分析法计算两种不同材料内固定后寰椎、枢椎、内固定材料以及C2/3的关节突关节应力变化,并进行统计学分析. 结果 (1)所建寰枢椎脱位复位与内固定有限元模型几何相似性好,共包含53586个节点、180784个单元;(2)在模拟头颅位于中立时,应力集中区域分别为C2/3关节突,其次是寰椎前弓、后弓和侧块;再次为C2椎弓;(3)镁合金和钛合金两种材料制备的TARP系统,在相应的力学分布上差异有统计学意义(P＜0.05) 结论 (1)应用CT扫描获取寰枢椎空间结构信息建立的寰枢椎模型可用于生物力学试验;(2)采用现有的钛合金TARP系统治疗寰枢椎脱位,保持寰椎前弓、后弓完整,侧块处植骨融合确实,可以更好保持寰枢椎的稳定性;寰枢椎融合后,相邻节段的关节突受力增加,加速退变,应密切随访;(3)相对于钛合金TARP,采用镁合金材料制备TARP系统进行复位固定,前述应力集中区域的峰值降低,应力分布均匀性提高.     

MR and cryomicrotomy of C1 and C2 roots

Paramedian sagittal MR images and cryotome sections in four cadavers were correlated with eight clinical MR studies to analyze the appearance of the C1 and C2 nerve roots and adjacent tissue. The C2 nerve roots and anatomically related venous plexus were identified. The C1 root, although not visualized by MR, could be localized by its relation to the vertebral artery, C1 lateral mass, and posterior arch.     

Hypertrophic anterior tubercles of C5 and C6 on CT

Summary Hypertrophy of the anterior tubercles of the transverse processes of the fifth and sixth cervical vertebrae is a rare congenital anomaly. We present the CT-appearance of this unusual variant.     

Absorbed dose from 14C xylose and 14C mannose

Tissue distribution and excretion studies have been performed in rats and mice for up to 1 week after oral administration of 14C xylose and 14C mannose. The effective dose-equivalent is calculated to be 15 microSv/MBq for xylose and 120 microSv/MBq for mannose. Since there was no clearance of mannose during the period of the study, the effective dose-equivalent for mannose is almost entirely dependent upon the assumptions made about expected lifetime exposure.     

Investigation of Damage to Multilayer Optics in X-Ray Laser Cavities: W/C, WRe/C, WC/C, Stainless-Steel/C, and Cr3C2/C Mirrors

In many applications, multilayer mirrors are exposed to damaging fluences of x rays. In x-ray laser cavities intense optical and broad-band x radiation, from the x-ray laser plasma amplifier, can damage multilayer mirrors on time scales of hundreds of picoseconds. We describe experiments using short duration (500 ps) bursts of soft x rays from a laser produced gold plasma to damage multilayer mirrors designed to reflect wavelengths close to 45 ? at normal incidence. The effect of the damaging x-ray flux on normal incidence reflectivity was time resolved for W/C, WRe/C, WC/C, 303-stainless-steel/C, and Cr3C2/C multilayers. The damage thresholds of the different mirrors were compared, and the Cr3C2/C mirrors were found to be the most resilient. The outer layers of the multilayers were observed to expand slowly as x rays were absorbed, and a more rapid expansion then preceded the total loss of reflectivity, at temperatures well below the melting temperature of the mirror components. It is believed that the dominant expansion mechanism is a change in the amorphous carbon layers to a more graphitic structure. The data are fit quite well by a model that assumes expansion of up to 25% in the thickness of the outermost carbon layers, followed by intermixing of the hotter layers. The rapid expansion has been observed to occur in times from 40 to 150 ps and may be the fastest resolution to date of the phenomenon of graphitization. The integrated reflectivity of the mirrors was observed to increase by up to a factor of 2.5 as they damaged; this reflectivity increase may be consistent with a reduction in the layer roughness.     

Pseudosubluxation of C2 on C3 in polytraumatized children--prevalence and significance.

AIM: Pseudosubluxation of C2 on C3 is a recognized physiological variant in the upper cervical spine radiographs of normal children. The aim of this study was to determine the prevalence of this variant in children admitted with serious polytrauma, and to explore its significance in this setting. PATIENTS AND METHODS: A retrospective review was performed of 138 patients under 16 years of age admitted with polytrauma via The Helicopter Emergency Medical Service. All patients wore hard collars and underwent immediate horizontal beam lateral cervical spine radiography. Normal and C2/C3 pseudosubluxation groups were defined using standard criteria. The two groups were compared in terms of age, presence of an endotracheal tube, injury severity, and outcome. RESULTS: There were 108 (78.3%) children in the normal group and 30 (21.7%) in the C2/C3 pseudosubluxation group. No significant differences in sex ratio, intubation status, injury severity, or outcome were found. Patients in the pseudosubluxation group were significantly younger. CONCLUSION: In paediatric polytrauma it is essential to establish the integrity of the cervical spine promptly as this will deter unnecessary further imaging and investigation. In our study 21.7% of cases had C2/C3 pseudosubluxation on admission radiographs. We have shown that C2/C3 pseudosubluxation has no significant association with intubation status, injury severity, or outcome. We conclude that C2/C3 pseudosubluxation can be considered a benign variant even in the setting of polytrauma.     

Vertical dislocation of the C1 and C2 vertebrae in rheumatoid arthritis

In a retrospective analysis of 450 patients with rheumatoid arthritis the cervical films were reviewed to detect vertical dislocation of the C1 and C2 vertebrae. A frequency of 10 per cent was found among all patients and of 24 per cent among those with cervical arthritis. The authors' method of measuring vertical dislocation at conventional radiography turned out to be superior to the method of McGregor , especially in cases with severe dislocation. The vertical dislocation was shown to be preceded by a horizontal dislocation and the appearance of vertical dislocation diminished or abolished the horizontal dislocation. Progression occurred in many cases and was combined with erosions of the atlas and axis. In more than half of the patients there was also contemporaneously a subaxial dislocation. Neurologic symptoms were more often occurring in patients with a severe vertical dislocation and in patients with spinal stenosis at the C1 level.     

C／C复合材料表面聚多巴胺涂层的制备及性能研究

目的：碳／碳（ C／C）复合材料为当前极具潜力的骨修复生物材料,在其表面制备聚多巴胺涂层旨在改善C／C复合材料亲水性和生物活性。方法制备一系列不同涂覆时间、涂覆环境（空气或富氧）条件的C／C复合材料表面聚多巴胺涂层,采用水接触角测试、扫描电子显微镜、能谱分析、原子力显微镜及蛋白吸附等表征手段探索不同制备条件对各项性能的影响规律,得出较佳制备条件。结果反应条件为多巴胺浓度2．0 g／L,涂覆时间30 min（氧气）＋11．5 h（空气）时,聚多巴胺涂层水接触角由空白对照组的64．0°下降至25．9°,其亲水性得到极大的改善;通过扫描电子显微镜、能谱分析及原子力显微镜测试得出该涂层均匀且致密;同时蛋白吸附含量为0．2817 mg。结论在C／C复合材料表面制备了聚多巴胺涂层,极大地改善了C／C复合材料的亲水性和生物活性。这一结果提示聚多巴胺涂层的C／C复合材料可作为新一代骨组织修复材料,为后续医学应用提供了理论依据。     

Structural Changes Study of Co/C and Ni/C Multilayers upon Annealing

A detailed study of structural changes occurring in films and on boundaries in multilayers upon annealing with EXAFS, WAXS, and SAXS methods was performed. The optimum temperature of annealing for the Ni/C and Co/C multilayers obtained by the pulsed laser evaporation method was found.