数字化微笑设计在前牙瓷贴面美学修复中的应用及其修复效果分析

目的：分析结合数字化微笑设计（DSD）进行前牙瓷贴面修复患者的术后满意度及修复体的修复效果,探讨其在前牙美学修复中的应用。方法：选择因四环素牙、氟斑牙、牙体着色、轻度釉质缺损和前牙散在间隙等原因要求进行美学修复,且临床诊断符合贴面修复适应证的患者32例共91颗前牙。术前采用DSD软件对患者进行牙齿形态的美学分析及虚拟修复效果的预览,并在设计结果指导下进行牙体预备,常规印模制取后制作IPS e-max瓷贴面,最后完成永久修复体的戴入。在治疗完成后采用调查问卷的形式让患者对修复体的外形、与邻牙协调程度、颜色、发音、微笑效果和医患交流等6项内容作出满意度评价,并在治疗后1、3、6和12个月参照改良版美国公共卫生署（USPHS）标准对瓷贴面的临床修复效果进行评估。结果：患者对于各项调查内容的满意率均可达90%以上,其中对于微笑效果和医患交流2项满意率高达100%。将DSD应用于瓷贴面修复后,患者对于最终修复体的功能、美学效果和医患交流体验等各方面满意度较高。各时期修复体临床表现,修复后1个月,4颗牙齿出现轻度牙龈炎,3颗牙齿出现术后敏感;修复后3个月,1颗修复体出现不影响美观及功能的微小缺损,3颗牙齿出现牙龈轻度红肿,1颗修复体轻微变色;修复后6个月,1颗修复体出现切缘缺损,4颗牙齿出现轻度牙龈炎;修复后12个月,2颗牙齿出现修复体缺损,3颗牙齿修复体边缘欠密合,1颗牙齿出现牙龈炎。修复后出现牙龈炎症反应的患者在经过正确的口腔卫生指导后牙周状况均有明显好转,且上述缺损均不影响修复体的美观和功能,调磨后可正常使用,医患双方对修复体的修复效果均满意。结论：将DSD与瓷贴面修复联合应用是一种可获得较高患者满意度和理想修复效果的前牙美学修复方案。     

Comparison of hydraulic and hemolytic properties of different impeller designs of an implantable rotary blood pump by computational fluid dynamics

A mixed-flow blood pump for long-term applications has been developed at the Helmholtz-Institute in Aachen, Germany. Central features of this implantable pump are a centrally integrated motor, a blood-immersed mechanical bearing, magnetic coupling of the impeller, and a shrouded impeller, which allows a relatively wide clearance. The aim of the study was a numerical analysis of hydraulic and hemolytic properties of different impeller design configurations. In vitro testing and numerical simulation techniques (computational fluid dynamics [CFD]) were applied to achieve a comprehensive overview. Pressure-flow charts were experimentally measured in a mock loop in order to validate the CFD data. In vitro hemolysis tests were performed at the main operating point of each impeller design. General flow patterns, pressure-flow charts, secondary flow rates, torque, and axial forces on the impeller were calculated by means of CFD. Furthermore, based on streak line techniques, shear stress (stress loading), exposure times, and volume percentage with critical stress loading have been determined. Comparison of CFD data with pressure head measurements showed excel-lent agreement. Also, impressive trend conformity was observed between in-vitro hemolysis results and numerical data. Comparison of design variations yielded clear trends and results. Design C revealed the best hydraulic and hemolytic properties and was chosen as the final design for the mixed-flow rotary blood pump.     

基于快速成型技术的个体化人工股骨髁关节面的设计与应用

目的设计、制造一种基于快速成型技术、复合异体半关节移植的个体化人工股骨髁关节面,探讨解决异体半关节移植中异体关节软骨坏死和异体-自体关节形状不匹配的方法。方法对异体半关节和骨肿瘤患肢股骨髁外表面行螺旋CT扫描,将CT断层图像进行矢量转换后在Surfacer 9．0软件进行矢量化三维重建,提取出合适的异体骨软骨下骨和患者关节软骨表面轮廓的三维图像,在计算机辅助下设计人工关节面,应用LPS600快速成型机制出快速成型树脂模型,以钛合金为材料铸造关节面假体主件,通过融合笼将关节面固定于关节上,抛光后获得人工关节软骨面成品。2002年2月对1例男性14岁右股骨下段骨肉瘤患者,行右股骨下段瘤段切除、人工股骨髁关节面复合大段同种异体骨移植重建股骨下端骨缺损术。结果新型复合异体半关节移植的个体化人工股骨髁关节假体与异体骨、对侧关节匹配良好;应用后随访16个月,膝关节功能良好。结论个体化股骨髁关节面明显改善了异体半关节移植患者的膝关节功能,为异体半关节移植中存在的异体关节软骨坏死和异体一自体关节形状不匹配提供一种解决方案。     

Comparison of Stent Free Cell Area and Cerebral Lesions after Unprotected Carotid Artery Stent Placement

Objective

This study evaluates the correlation between closed, semi-closed and open-cell stent design and the association between stent type and clinical outcome as well as magnetic resonance imaging (MRI) findings.

Design

A total of 194 patients who underwent unprotected carotid artery stenting (CAS) as well as diffusion-weighted magnetic resonance imaging (DW-MRI) before and after intervention were retrospectively reviewed.

Materials and methods

Three stent designs were studied: closed cell, semi-closed cell and open cell. Spearman’s Rho test was performed between the stent free cell area and the number and area of ischaemic lesions found after intervention. Adverse events were evaluated.

Results

There was no significant difference in clinical outcome between the three stent groups (Zilver, Cook Europe, Denmark; Smart, Codman, MA; and Wallstent, Stryker, MN, USA). A significant correlation was found between the stent free cell area and the number and area of new ischaemic lesions on DW-MRI (P = 0.023). There were significantly fewer new lesions with an open-cell design (Zilver; 12.76 mm² free cell area) than with a closed-cell design (Wallstent; 1.08 mm² free cell area).

Conclusions

Open-cell stent was related to a lower number and area of silent cerebral ischaemic lesions after unprotected CAS. However, clinical outcome, measured by incidence of adverse events and clinical neurologic assessment, was not significantly different between patients with different stent designs.     

个性化假体三维设计及其在恶性骨肿瘤初次置换与翻修术中的应用

目的探讨基于骨肿瘤患者CT扫描的人工髋、膝关节假体计算机辅助三维个性化设计方法和手术效果。方法选取股骨恶性骨肿瘤患者,进行CT扫描,三维重建,计算机辅助术前规划、模拟手术和假体三维设计,发送STL文件定制个性化假体。依据术前规划进行保肢手术,观察手术效果。结果设计并定制了带定位标识的个性化人工股骨柄肿瘤假体和人工膝关节铰连式肿瘤假体,手术瘤骨切除彻底、假体安装顺利、位置合适,术后双下肢等长。结论基于CT重建能设计出带标识个性化人工关节肿瘤假体,有利于保肢手术精确恢复下肢长度和精确安装假体位置。     

CroweⅣ型髋关节发育不良全髋关节置换术前计算机辅助设计

目的 探索采用计算机辅助技术,对接受全髋关节置换(total hip arthroplasty,THA)的CroweⅣ型髋关节发育不良患者进行术前评估,确定髋臼大小、骨缺损程度,并在此基础上辅助手术设计、假体选择及骨缺损修复.方法 2011年3月至10月,共10例(13髋)CroweⅣ型高位脱位髋关节发育不良患者接受THA治疗.患者均为女性;年龄32～74岁,平均42岁.所有患者术前行髋关节三维CT扫描,然后将扫描数据输入Superlmage软件重建骨盆及髋臼.重建后在不同角度精确评估真臼位置,测量真臼大小及前后柱厚度,评估骨缺损程度;将髋臼试模、骨缺损修复材料(钽金属垫块)按1:1大小扫描输入计算机系统,进行术前模拟安放,确定髋臼假体大小、安放位置;髋臼假体安放后评估遗留的骨缺损,确定骨缺损修复材料,进行骨缺损修复模拟测试.结果 9例(12髋)术中实际安放髋臼假体型号与术前计算机辅助设计一致,1例(1髋)假体型号较术前设计大一号.所有患者髋臼安放位置与术前计划一致,均安放于真臼.髋臼骨缺损修复按术前设计:4髋因髋臼顶部骨缺损明显(臼顶部骨性覆盖＜70％),采用钽金属垫块修复骨缺损,以增强髋臼的稳定性;7髋采用Harris法自体股骨头植骨修复骨缺损;2髋髋臼杯植入后臼顶覆盖可,术中未植骨.结论 对CroweⅣ型髋关节发育不良者行计算机辅助下THA术前设计,有助于术前精确评估真臼发育情况、大小及髋臼骨缺损,提高手术治疗精确性.     

计算机辅助膝内翻及外翻畸形分析和精确矫形

目的探讨计算机辅助膝关节内外翻畸形分析和精确矫形的新方法,评价计算机辅助技术在膝内外翻畸形治疗中的价值。方法2005年9月～2010年9月共收治膝内、外翻畸形患者18例;膝内翻4例,膝外翻14例。其中男6例,女12例;年龄14～54岁,平均25．4岁。所有患者采用薄层CT扫描获取双下肢的二维图像数据,计算机辅助建立的双下肢三维解剖模型,将双下肢三维解剖模型导入逆向工程软件Imageware中,通过计算机辅助精确测量股骨角、胫股角、胫骨关节面夹角等参数,根据计算机辅助测量结果,选择合适的截骨部位、截骨角度,通过提取表面点云数据,CAD设计个性化辅助截骨模板,最后采用计算机模拟设计膝关节内外翻畸形的精确截骨和矫形的手术过程。术中根据计算机辅助模拟的手术方案,对4例膝关节内翻畸形患者采用胫骨近端截骨＋内固定术,14例膝关节外翻畸形患者采用股骨髁上截骨＋内固定术。采用膝关节HSS评分标准评定术前、术后的膝关节功能。结果所有患者均得到随访,随访时间9～36个月,平均18．7个月。术后早期X线证实：膝内、外翻畸形完全矫正,下肢负重力线恢复正常。术前计算机辅助测量与X线的测量值,两者测量无统计学差异（P〉0．05）;术前及术后X线测量的股骨角、胫股角、胫骨关节面夹角等参数对比,具有统计学差异（P〈0．05）。根据膝关节HSS评分标准：术前（55．4±15．2）分,术后半年（81．8±9．6）分,两者差异有统计学意义（P〈0．05）。传统方法组与计算机辅助矫形组相比,术后口角、B角和膝关节功能评分具有统计学差异（P〈0．05）。随访期间未发现有内固定失败、骨不愈合、膝内外翻复发、无神经血管损伤等并发症;其中3例患者术后2周出现异体骨排斥反应,给予伤口换药治疗后好转,随访期间未发现骨不愈合。结论采用计算机辅助膝内外翻分析和精确矫形,将膝内外翻畸形的精确矫形提升到数字化水平,具有更加精确、更加可靠、更加良好的治疗效果。     

Polynomial matrix solution of H2 optimal control problem for state‐space systems

A polynomial matrix solution to the H₂ output feedback optimal control problems is obtained for systems represented in state‐equation form. The proof does not invoke the separation principle but is obtained in the z‐domain. The cost function includes weighted states, which allows the so‐called standard system model problem to be solved. This encompasses the class of inferential control problems. The results also enable the two‐degree‐of‐freedom optimal control solution properties to be explored. Copyright © 2002 John Wiley & Sons, Ltd.     

Operative treatment of intertrochanteric hip fractures: an overview of modern advances and techniques

Hip fractures have been one of the most studied injury pattern in adults. The number of hip fractures is increasing exponentially; furthermore, the cost of treatment places great economic strain on society. There have been recent developments in hip-fracture treatment, particularly involving the intertrochanteric region, with emphasis on deformity prevention to try to optimize patient functional outcomes. In this article, we outline some of these developments with an emphasis on changes in implant design.     

Post-Traumatic Periprosthetic Tibial and Fibular Fracture After Total Ankle Arthroplasty: A Case Report

Periprosthetic fractures after total ankle arthroplasty are uncommon, with most cases occurring intraoperatively. We describe a post-traumatic periprosthetic fracture of the distal tibia and fibula after total ankle arthroplasty that was treated with minimally invasive plate osteosynthesis. It is important for orthopedic surgeons not only to recognize the risk factors for postoperative periprosthetic total ankle arthroplasty fractures, but also to be familiar with the treatment options available to maximize function and minimize complications. The design of the tibial prosthesis and surgical techniques required to prepare the ankle joint for implantation are important areas of future research to limit the risk of periprosthetic fractures.