Reference marker stability in computer aided orthopedic surgery: a biomechanical study in artificial bone and cadavers.

INTRODUCTION: In computer assisted orthopaedic surgery, rigid fixation of the Reference Marker (RM) system is essential for reliable computer guidance. A minimum shift of the RM can lead to substantial registration errors and inaccuracies in the navigation process. Various types of RM systems are available but there is little information regarding the relative stabilities of these systems. The aim of this study was to test the rotational stability of three commonly used RM systems. MATERIALS AND METHODS: One hundred and thirty Synbones and 15 cadavers were used to test the rotational stability of three different RM systems (Schanz' screw, RM B and RM C adjustment systems). Using a specially developed testing device, the peak torque sustained by each RM system was assessed in various anatomical sites. RESULTS: Comparison of means for Synbone showed that the RM C was the most stable (mean peak torque 5.60 +/- 1.21 Nm) followed by the RM B system (2.53 +/- 0.53 Nm) and the RM A (0.77 +/- 0.39 Nm) (p<0.01). The order of stability in relation to anatomical site was femoral shaft, distal femur, tibial shaft, proximal tibia, anterior superior iliac spine, iliac crest and talus. Results from the cadaver experiments showed similar results. Bi-cortical fixation was superior to mono-cortical fixation in the femur (p<0.01) but not the tibia (p=0.22). CONCLUSION: The RM system is the vital link between bone and computer and as such the stability of the RM is paramount to the accuracy of the navigation process. In choosing RM systems for computer navigated surgery surgeons should be aware of their relative stability. Anatomical site of RM placement also affect the stability. Mono-cortical fixation is generally less stable than bi-cortical.     

计算机手术导航系统对股骨头表面假体植入精确度的研究

目的研究非影像手术导航系统对股骨头表面假体植入位置的影响。方法25例股骨头坏死患者（共32髋）。其中男性16例，女性9例，年龄（36±7）岁。随机分为2组，计算机导航手术组（导航组）11例（16髋），在导航系统下进行股骨头表面置换术，设定髋最佳植入柄颈角为0°，柄干角为140°；对照组14例（16髋）采用传统手术。术后测定假体植入的角度，进行手术评估。结果术后导航组植入股骨假体柄干角为（140．5±1．7）°，对照组为（135．9±6．5）°，导航组的股骨假体柄颈角为（O．30±1．40）°，对照组柄颈角为（-4．93±4．30）°，两组差异具有统计学意义（P〈0．05）。Harris评分，导航组优14髋，良2髋；对照组优9髋，良4髋，中3髋。导航组无一例发生肢体缩短、旋转、内外翻畸形，对照组2例发生短缩畸形，1例内翻15°畸形。随访（14±4）个月，均无假体松动、脱位。结论在非影像手术导航系统下手术操作可以精确地植入假体，减少假体松动的发生,具有重要的临床价值。     

计算机导航下经Wiltse入路钉棒内固定治疗胸腰椎骨折的疗效观察

目的探讨计算机导航辅助下Wiltse入路椎弓根钉棒内固定术治疗胸腰椎骨折的临床疗效及优势。方法回顾性分析2015年7月至2017年6月,我科收治的53例胸腰椎骨折患者,均为单节段骨折。按手术方式分为A组29例和B组24例,A组患者采用计算机导航辅助下Wiltse入路椎弓根钉棒内固定术治疗,B组采用传统后正中入路开放手术。对两组患者术中出血量、术后引流量、置钉准确率、手术前后椎体后凸Cobb角,手术前后VAS评分等指标进行评估。结果两组患者手术时间相差无几,术中出血量、术后引流量A组患者均少于B组患者,差异均有统计学意义(P0.05);患者置钉准确率A组(99.1%)高于B组(87.5%),差异有统计学意义(P0.05);术后24小时及术后3月两组患者伤椎后凸Cobb角比较差异无统计学意义;术后24小时A组VAS评分低于B组,差异有统计学意义(P0.05),术后3月两组比较差异无统计学意义(P0.05)。结论计算机导航辅助下肌间隙入路椎弓根有效钉棒内固定技术治疗胸腰椎骨折疗效满意,能减少手术创伤,降低手术风险。     

Execution accuracy of bone resection and implant fixation in computer assisted minimally invasive total knee arthroplasty

While computer assisted total knee arthroplasty (TKA) has been documented to increase the surgical accuracy in the planning process, there is little information about the accuracy in execution processes. We aimed to determine the accuracy of execution processes for bone resections and implant fixation in TKAs performed with the techniques of computer assisted navigation and minimally invasive surgery. Execution deviations, defined as the differences between planned targets and executed results, were evaluated for bone resections and implant fixation in 107 TKAs. In tibia resection, the mean resection thickness, coronal alignment, and sagittal alignment were 0.2 mm smaller, 0.3° more valgus, 0.3° less posterior slope than the planned, respectively. In femur resection, the mean resection thicknesses in the medial and lateral femoral condyles, coronal alignment, and sagittal alignment were 0.6 mm smaller, 0.8 mm smaller, 0.1° more varus, and 0.7° less posterior slope than the planned, respectively. In implant fixation, the mean coronal alignment and degree of extension was 0.7° more valgus and 1.6° decrease than the planned, respectively. Only the occurrence of unacceptable executions in implant fixation had significant effects on the final coronal alignment. The density of a bone and the quality of saw blade had significant effect on the accuracy of bone resections. Execution deviations from planned alignment commonly occur in computer-assisted minimally invasive TKA, resulting typically from the techniques of bone resections and implant fixation, and this information should be considered to improve the surgical accuracy of navigated TKAs.     

In Vivo Tissue Response to Ultrasound Assisted Application of Biodegradable Pins into Cortical and Cancellous Bone Structures: A Histological and Densitometric Analysis in Rabbits

In orthopaedic traumatology biodegradable pins are increasingly used for fixation of small bone fragments. In the present study, the ultrasound-assisted anchoring technique (SonicFusion technique), a osteosynthesis method being recently introduced in cranial applications, in which ultrasonic energy is used to insert and anchor polymer pins in bone, was compared with the conventional pin application procedure. The aim of the present study was to assess the short and long term thermal impact of two different ultrasonic energy levels on different bone structures in the distal medial femur of rabbits. The treatment groups consisted of customized polylactide pins applied at a low and a high energy level, the Reference Control and a Negative Control. The thermal effect on bone tissues was evaluated by means of qualitative and semi-quantitative histology and micro-computerized tomography. Five days following surgery, all implant sites showed no tissue damage but normal signs of early ongoing tissue repair. Enhancing the energy level by about 30% had no significant impact on the tissue response. At 4 weeks after surgery test sites covered by ultrasound-aided implantation showed a significantly enhanced bone/implant contact as compared to pins applied by conventional application. In conclusion, the ultrasound assisted anchoring technique not only did not impair bone regeneration, but even improved implant integration.     

基于可视化交互的计算机辅助椎弓根螺钉植入系统及关键技术

当前脊柱手术方案制定方式无法适应复杂的临床环境与高风险控制需求,本研究为实现安全、个性化手术规划目的,开发了计算机辅助椎弓根螺钉植入系统。首先,系统根据图像预处理结果,利用面绘制技术重建脊柱模型。然后结合二维像素擦除与多平面切割技术,提出新的脊椎骨分离算法,去除因各骨块间存在冗余连接而产生的计算偏差。最后,系统提取选定参考平面与分离骨块的相交轮廓曲线,实现椎弓根螺钉置入手术过程的直观模拟。实验结果表明：该系统可以精确地完成脊椎骨模型的分割,并快速直观地完成椎弓根螺钉的虚拟置入,为医生设计手术方案提供科学依据。     

In vivo tissue response to ultrasound assisted application of biodegradable pins into cortical and cancellous bone structures: a histological and densitometric analysis in rabbits

In orthopaedic traumatology biodegradable pins are increasingly used for fixation of small bone fragments. In the present study, the ultrasound-assisted anchoring technique (SonicFusion technique), a osteosynthesis method being recently introduced in cranial applications, in which ultrasonic energy is used to insert and anchor polymer pins in bone, was compared with the conventional pin application procedure. The aim of the present study was to assess the short and long term thermal impact of two different ultrasonic energy levels on different bone structures in the distal medial femur of rabbits. The treatment groups consisted of customized polylactide pins applied at a low and a high energy level, the Reference Control and a Negative Control. The thermal effect on bone tissues was evaluated by means of qualitative and semi-quantitative histology and micro-computerized tomography. Five days following surgery, all implant sites showed no tissue damage but normal signs of early ongoing tissue repair. Enhancing the energy level by about 30% had no significant impact on the tissue response. At 4 weeks after surgery test sites covered by ultrasound-aided implantation showed a significantly enhanced bone/implant contact as compared to pins applied by conventional application. In conclusion, the ultrasound assisted anchoring technique not only did not impair bone regeneration, but even improved implant integration.     

导航机器人与透视引导椎弓根置钉的Meta分析

文题释义：导航机器人：又称为机器人辅助手术系统,机器人辅助手术系统是集多项现代高科技手段于一体的综合体,在世界精准微创外科领域是当之无愧的革命性外科手术工具。机器人辅助手术系统具有精准、稳定及三维放大视野等优点。 椎弓根螺钉置入：目前椎弓根螺钉的置入技术已经比较成熟,螺钉的误置一般发生在脊柱解剖结构有改变如结构性侧弯、发育畸形及严重退行性改变导致骨性标志不清时。在这些情况下常规的“标准化置钉”将显得比较困难。 背景：计算机导航系统与骨科手术机器人近年来在脊柱外科得到了高速发展,但是计算机导航或导航机器人的手术效果仍受到诸多质疑。 目的：通过Meta荟萃分析拟比较导航机器人与透视引导椎弓根置钉精度的差异。 方法：检索包括国内外于2008年8月至2019年8月已发表的临床对照研究。所检索的数据库包括Embase、PubMed、中国知网、万方等数据库。中文检索关键词为：导航机器人、透视引导、椎弓根螺钉、椎弓根钉、椎弓根钉棒、椎弓根内固定,检索策略为：“椎弓根螺钉”并且“透视引导”或“导航机器人”;英文检索关键词为：Robot assisted,Fluoroscopy guided,Pedicle screw,Pedicle stick,Pedicle screw fixation,检索策略为“Pedicle screw”OR“Pedicle stick”OR “Pedicle screw fixation”AND“Fluoroscopy guided”OR“Robot assisted”。阅读文献提取数据后,采用Review Manager 5.3 软件进行数据分析。 结果与结论：①依据上述策略,共检索到357篇研究文献,并从中最终纳入19篇文献,其中英文17篇,中文2篇;②Meta分析结果显示,导航机器人组的置钉精度优于透视引导组[95%CI(1.82,2.52),P < 0.001],导航机器人组的手术并发症发生例数[95%CI(0.25,0.69),P=0.000 6]及翻修例数[95%CI(0.23,0.71),P=0.002]均少于透视对照组,其差异均有显著性意义;③提示在评价椎弓根螺钉置入方式时,导航机器人具有更高的置钉精度和更少的并发症发生及翻修例数,在准确性和安全性上均优于传统透视引导技术。当然考虑到导航机器人技术昂贵的价格和复杂的操作步骤,具体置钉方式的选择仍应遵循个体化治疗原则。 ORCID: 0000-0003-4818-901X(徐朝健) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

骨水泥、钉道植骨强化动力髋螺钉固定修复老年骨质疏松性股骨转子间骨折

背景：对于老年骨质疏松性髋部骨折的动力髋螺钉固定,如能避免使用过程中造成的骨量丢失,或是采用其他手段增加固定螺钉把持力,将改善动力髋螺钉固定的治疗效果。 目的：对比研究3种固定方式修复老年骨质疏松性股骨转子间骨折的效果。   方法：回顾性分析近5年来采用常规动力髋螺钉内固定、骨水泥强化后动力髋螺钉固定及主钉道压配植骨配合动力髋螺钉固定3种固定方式治疗老年骨质疏松性股骨转子间骨折患者的资料,分别设为对照组、骨水泥组和植骨组。 结果与结论：经固定后2年随访,植骨组、骨水泥组和对照组Harris髋关节功能评分优良率分别为95%,80%,70%。植骨组骨折临床愈合时间明显缩短(P < 0.05),出现螺钉固定失败情况与骨水泥组相当。对照组较其他2组相对更多出现退钉等内固定失败情况。结果表明,与其他常规动力髋螺钉内固定、骨水泥强化后动力髋螺钉固定方式相比较,主钉道压配植骨配合动力髋螺钉内固定的疗效及安全性更好。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

多节段胸腰椎结核的外科治疗

目的探讨多节段胸腰椎结核采取前后路联合入路病灶清除植骨内固定联合化疗的临床疗效。方法选取2007年1月至2017年12月本院收治的多节段胸腰椎结核患者28例,术前常规化疗2～4周,平均3周,手术先采用胸腰椎后入路行椎弓根螺钉固定,再行侧前方入路彻底清除病灶内脓肿、死骨、肉芽组织及坏死椎间盘在病椎上下正常椎体内行内固定,采用"钛网+自体髂骨植骨支撑,15例、自体髂骨植骨支撑10例、自体肋骨植骨支撑3例。结果28例患者均获得1～6年的随访,平均2.2年。其中合并脊髓损伤伴不全瘫者17例,按Frank分级:B级2例,C级11例,D级4例。B级2例恢复到C级;C级11例中,其中5例恢复到D级,6例恢复到E级;D级4例均恢复到E级。病灶静止、骨性融合26例,术后半年内有2例复发。1例再次手术,重新行病灶清除,去除植骨块改用钛网加髂骨植骨8个月后骨性融合;1例抗痨治疗无效,患者放弃治疗。无钢板、螺钉松动、断裂。结论术前常规化疗,术中彻底清除病灶植骨融合内固定,术后继续化疗,是外科治疗多节段胸腰椎结核获得良好效果的保证。     

胫骨外侧平台骨折关节镜下经皮复位植骨螺钉内固定：4年随访

背景：有研究表明,胫骨平台骨折切开复位内固定的病例中远期出现继发性骨性关节炎,但很少有研究者报道关节镜辅助下胫骨平台骨折内固定的中远期效果。 目的：关节镜下经皮植骨或螺钉内固定治疗胫骨平台骨折后1年及4年后的效果及放射学评价。 方法：收集2007年3月和2009年3月期间,汕头大学医学院第一附属医院骨科收治的胫骨外侧平台骨折经关节镜辅助下植骨或螺钉内固定病例的资料,记录骨折Schatzker分型、术中平台侧软骨缺损、股骨侧软骨损伤、关节内软组织损伤、复位不足及术后外侧平台骨折沉降资料。评估植骨或螺钉内固定后1年和4年时膝关节Lysholm评分、Ahlback骨性关节炎分级以及Rasmussen功能评分和放射性评分。 结果与结论：23例患者完成随访研究,植骨或螺钉内固定后1,4年平均Lysholm评分分别为90分和87分(P=0.23),Rasmussen功能评分平均为26分和24分(P=0.30)。术后4年有11例(47.8%)出现膝关节骨性关节炎,Rasmussen放射学评分从术后初期17.4分下降至术后4年的13.6分(P=0.01)。各型骨折与预后无相关性;老年病例、软骨损伤或/和缺损、关节内软组织损伤以及术后外侧平台沉降影响术后中期功能和影像学结果;但统计中发现,胫骨侧软骨缺损对于中期发生关节炎的作用远低于股骨侧的软骨损伤。结果提示：术后早期的影像学结果并不能完全与术后4年的结果相匹配,但中期随访的临床和功能结果仍然满意。患者年龄、合并关节内软骨和软组织损伤以及术后胫骨平台沉降均是影响治疗后患膝出现骨性关节炎的消极因素。胫骨侧软骨缺损对于中期发生关节炎的消极作用远低于股骨侧的软骨损伤,可能与完好的外侧半月板功能有关。     

新型定位装置在股骨颈骨折空心螺钉内固定中的辅助定位

文题释义：股骨颈骨折：多见于中老年人,青壮年可因高暴力损伤引起该类型骨折。骨折后患者髋部疼痛、肿胀,大转子处可有压痛及叩击痛,下肢存在短缩、内收、外旋等畸形。影像学检查可清晰地显示骨折的部位、类型及移位程度。 克氏针定位装置：该辅助定位装置适用于股骨颈骨折闭合复位空心螺钉内固定,与传统徒手操作相比,具有定位效率高、透视次数少、手术时间短、患者创伤小等优点;与骨科机器人、计算机导航系统等辅助定位装置相比,精确度有待提高,较适用于广大基层医院。 背景：目前骨科机器人、计算机导航系统等智能定位装置在股骨颈骨折闭合复位手术过程中的应用逐步开展,但基层医院仍需一种廉价的辅助定位装置。 目的：探讨一种股骨颈克氏针定位装置在股骨颈骨折空心螺钉内固定过程中辅助定位的效果。 方法：回顾性分析2016年2月至2018年3月滨州医学院附属医院收治的54例股骨颈骨折患者的临床资料,根据有无辅助定位装置分为2组,徒手定位组28例患者行传统徒手定位空心钉内固定;辅助定位组26例患者术中应用克氏针定位装置,定位针角度、方向、距离均可量化微调,辅助定位,引导置入空心螺钉。比较2组患者临床与影像资料。 结果与结论：①所有患者手术顺利,未发生血管、神经损伤等术中并发症;术后影像显示骨折复位良好,空心螺钉分布、角度、位置良好;②辅助复位组手术时间(49.27±4.86) min小于徒手定位组(59.64±8.02) min,差异有显著性意义(P < 0.01);辅助定位组透视次数明显少于徒手定位组,差异有显著性意义(P < 0.01);③2组随访时间、骨折愈合时间、末次随访Harris功能评分差异均无显著性意义(P > 0.05);辅助定位组Harris评分优良率为89%;④2组患者随访期间无股骨头坏死发生,晚期坏死率待随访;⑤提示克氏针定位装置在股骨颈骨折空心螺钉内固定过程中,可辅助定位,引导置入空心螺钉,能有效提高定位效率,减少透视次数,避免反复调整穿针对股骨颈骨质的损伤,促进患者恢复。 ORCID: 0000-0002-4576-3306(杜刚强) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Mechanical and histological evaluation of a PMMA-based bone cement modified with gamma-methacryloxypropyltrimethoxysilane and calcium acetate

Polymethylmethacrylate (PMMA) bone cement is widely used for prosthetic fixation in orthopaedic surgery; however, the interface between bone and cement is a weak zone. We developed a bioactive PMMA cement through modification with gamma-methacryloxypropyltrimethoxysilane (MPS) and calcium acetate. The purpose of this study was to compare the handling, mechanical and histological properties of the modified bone cement with those of the conventional cement. The modified specimens exhibited higher bonding strength between bone and implant. Histological observation and micro-focus X-ray computed tomogram (micro-CT) images showed that the modified cement exhibited osteoconduction, which the conventional PMMA bone cement lacked. The modification was found to be effective in enabling osteoconduction with PMMA bone cement, thus providing stable fixation for a long period after implantation.     

骨水泥强化椎弓根螺钉固定对骨质疏松患者有利无弊

背景：在对伴骨质疏松的腰椎疾病患者进行椎弓根螺钉固定手术时,椎体添加骨水泥可有效增加内固定稳定性,但对相邻节段的影响尚不明确。 目的：观察伴骨质疏松的腰椎疾病患者进行椎体骨水泥强化内固定后,早中期随访中骨水泥强化对相邻节段的影响。 方法：以87例伴骨质疏松的腰椎疾病患者为研究对象,均行椎弓根螺钉系统固定+后路椎管减压术,并分为3组：常规螺钉组,常规螺钉+骨水泥组,可灌注骨水泥螺钉+骨水泥组。样本平均随访6-18个月,平均随访为9个月。测量术前、术后3 d、末次随访的Oswestry功能障碍指数评分、固定节段上位相邻椎间隙高度、固定节段上位相邻椎体变形指数、固定节段椎体上缘终板及相邻上位椎体下缘终板凹陷角度、固定节段Cobb角。 结果与结论：①常规螺钉组、常规螺钉+骨水泥组、可灌注骨水泥螺钉+骨水泥组3组内末次随访功能障碍指数评分均较前明显减小(P < 0.05),组间两两对比无显著差异(P > 0.05)。表明骨质疏松患者脊柱后路固定时,是否添加骨水泥及不同添加方式,对早中期主观疗效影响无显著差异,且均可明显改善患者生活质量。②常规螺钉+骨水泥组、可灌注骨水泥螺钉+骨水泥组2组末次随访对术后3 d固定节段Cobb角变化小于常规螺钉组(P < 0.05),常规螺钉+骨水泥组、可灌注骨水泥螺钉+骨水泥组2组组间差异无统计学意义(P > 0.05)。表明添加骨水泥辅助的内固定稳定性明显优于未添加骨水泥常规手术。③常规螺钉+骨水泥组、可灌注骨水泥螺钉+骨水泥组2组术后3 d出现上终板凹陷角度增大;末次随访观察到相邻上位椎体下终板凹陷角度、椎体矩形指数及相邻椎间隙均减小,且前两项指标的改变程度明显大于常规螺钉组。表明添加骨水泥辅助内固定对相邻椎间盘退变程度无显著影响,但明显改变了相邻椎体终板及椎体的形态,增加了相邻椎体发生骨折的风险。     

同一体位OLIF联合后路导航辅助下经皮椎弓根螺钉固定治疗腰椎退行性疾病的初步应用

目的 评估同一体位斜外侧腰椎椎间融合术(OLIF)联合后路导航辅助下经皮椎弓根螺钉固定治疗腰椎退行性疾病的可行性、安全性及临床疗效。方法 回顾性分析2015年8月～2019年2月于本院行同一体位OLIF联合后路经导航辅助下皮椎弓根螺钉固定治疗的腰椎退行性疾病患者22例。统计手术时间、术中出血量、术中椎弓根螺钉置钉时间,利用腰痛及下肢痛视觉模拟评分(VAS)、Oswestry功能障碍指数(ODI)评估临床疗效。术后CT三维重建评估侧卧位经皮置钉的准确性及椎间融合率。结果 所有患者均获得随访,随访时间12～24个月,平均(15.6±4.8)个月。所有患者均顺利完成手术,手术时间(96.2±15.2) min,术中出血量(62.4±19.3)m L,总置钉时间(33.0±3.6) min。术后随访腰痛VAS评分、下肢痛VAS评分及ODI指数均较术前明显改善,差异具有统计学意义(P0.05)。置钉准确率94.3%,术后1年椎间融合率为100%。结论 同一体位OLIF联合后路导航辅助下经皮椎弓根螺钉固定手术可以避免术中变换体位,精简手术过程,节约手术时间,具有良好的可行性、安全性及临床疗效。     

The evolution of clinical applications of biodegradable implants in arthroscopic surgery

Arthroscopic surgery is the most recent orthopaedic discipline to embrace biodegradable implant technology. Osteochondral fractures have been shown to be amenable to arthroscopic fixation with biodegradable pins. The areas of most recent interest have been biodegradable interference screw fixation for ACL reconstruction in the knee, biodegradable suture anchors for rotator cuff repair and capsulolabral repair in the shoulder. Biodegradable implants have allowed a paradigm shift away from bionic (mechanical replacement) engineering and toward true biologic solutions to reconstructive problems in arthroscopic surgery.     

椎弓根螺钉内固定及计算机导航技术的发展与应用

背景：胸腰椎椎弓根螺钉内固定技术的开展,有力地推动了脊柱外科的发展,而脊柱计算机导航系统可以明显改进椎弓根螺钉植入的精确性和安全性。 目的：研究近年来椎弓根螺钉固定术临床应用进展。 方法：以“椎弓根螺钉固定术,计算机导航技术,临床应用进展”为关键词,采用计算机检索1999-01/2011-12相关文章。纳入与有关椎弓根螺钉固定及计算机导航技术在内固定过程中应用的文章;排除重复研究或Meta分析类文章。以25篇文献为主重点进行了讨论椎弓根螺钉固定术的研究进展及相关评价。 结果与结论：计算机辅助外科技术是基于计算机对大量数据信息的高速处理及控制能力,通过虚拟手术环境为外科医生从技术上提供帮助,使手术更安全、更准确的一门新技术。近年来,胸腰椎椎弓根螺钉植入技术的研究取得了很大发展,尤其是术中监测手段,已从传统的X线透视或摄片监测定位发展到计算机辅助技术进行可视化监测。计算机导航技术提供了可以从存储于计算机上的三维影像资料上模拟测量钉道长度、角度及椎弓根直径的功能,便于选择最佳长度与直径的椎弓根钉,使椎弓根螺钉手术更精确、简便、快速、安全,减少了术后并发症的发生。     

Percutaneous bone biopsy. A new application for 3D navigation: a pilot study.

Computer Tomography (CT) guided percutaneous bone biopsy has been established as a minimally invasive method for the rapidly obtaining samples from osseous lesions for histological examination. With this method, an overall accuracy of 90% can be obtained without a significant radiation exposure. The aim of this study was to develop a navigated sleeve for the Jamshidi needle in order to perform navigated, percutaneous bone biopsies with the help of Iso-C-3D. Utilizing this navigated biopsy needle, the procedure was analyzed for several parameters including precision, total operating time, and level of radiation exposure. By using the Iso-C-3D navigation the total operating time was 11.7 min (8-14.3) and radiation exposure was 1.6 (0.67-2.12 min). This study demonstrates that navigated percutaneous bone biopsies can be obtained fast and with low radiation exposure. The feasibility of Iso-C-3D navigated bone biopsies is tempered by the requirement a rigidly fixed dynamic reference frame.     

Computational simulations of stress shielding and bone resorption around existing and computer-designed orthopaedic screws

Failure of an orthopaedic fixation due to stress shielding and consequent screw loosening is a major concern among surgeons: the loosened screws could not only interfere with the healing process but also endanger adjacent anatomical structures. In this study, the effect of the screw's engineering design (dimensions, profile shape and material properties) on the load sharing with adjacent bone and consequent bone resorption was tested, using a set of two-dimensional computational (finite element) models. An algorithm simulating local bone adaptation to strain energy density (SED) mechanical stimuli was developed and used to evaluate the biomechanical performances of different commercial screws. Two new designs, a ‘graded-stiffness’ composite screw, with a reduced-stiffness titanium core and outer polymeric threads, and an active-compression hollow screw that generates compressive stresses on the surrounding bone, were also evaluated. A dimensionless set of stress transfer parameters (STPs) were utilised for ranking the performances of the different screws according to the expected screw-bone load sharing and its evolution with adaptation of the surrounding tissue. The results indicated that commercial wide (6mm thread diameter) trapezoidal and rectangular screw profiles have superior biomechanical compatibility with bone (i.e. predicted to be stable after 2 years). The graded-stiffness and active-compression screws provided the best biomechanical performances: bone loading around them was predicted to decrease by no more than 15% after 3 years, compared with a decrease of 55–70% in bone loading around commercially available screws. Computer simulations of bone adaptation around orthopaedic screws are demonstrated to be effective means for objective and quantitative evaluation of the biomechanical aspects of implant-tissue compatibility.     

计算机重建技术辅助胸椎椎弓根钉置入的准确性

背景：由于椎骨周围组织关系复杂,使得胸椎椎弓根钉置入成功率不是很理想。随着更精密的成像设备的出现,骨科术前检查变得更清晰,准确。借助数字化成像设备势必要提高椎弓根钉置入准确性。 目的：比较分析螺旋CT计算机三维重建辅助指导技术与传统徒手技术置入胸椎椎弓根钉成功率及准确性的差异。 方法：纳入56例胸椎损伤患者,内固定前根据患者意愿选择置钉方式,三维重建辅助组及传统徒手组各28例。置钉前三维重建辅助组患者全部采用128排高分辨率CT对胸椎进行扫描,得到的数据输入计算机数据库,根据软件生成的三维立体图像,模拟手术路径和置钉参数。传统徒手组患者行普通X射线和CT检测,不应用三维重建辅助组的重建和模拟功能。所有病例记录置钉成功率,内固定后再次进行螺旋CT扫描评估置钉准确性。 结果与结论：与传统徒手组比较,三维重建辅助组置钉成功率显著提高(P < 0.05),椎弓根穿破率显著降低(P < 0.05)。提示利用螺旋CT三维重建技术辅助胸椎椎弓根钉内固定,可以明显提高椎弓根钉置入的成功率和准确性。