节点文献

虚拟现实技术在全髋表面置换术中的应用

Application of Virtual Reality Technique in the Hip Resurfacing

【作者】 刘登均

【导师】 李奇;

【作者基本信息】 南方医科大学 , 骨外科, 2010, 硕士

【摘要】 股骨头缺血性坏死、先天性髋关节发育不良、股骨头骨骺滑脱、强直性脊柱炎等常见疾病其晚期结果是导致髋关节疼痛和严重的功能障碍,对于这类髋关节疾病晚期,较好的治疗方法是进行人工全髋关节置换。对于预期寿命长,骨质条件较好,活动量大,将来面临多次翻修的患者来说,选择全髋关节表面置换(hip resurfacing arthroplasty,HRA)更具以下特点:1.HRA可更精确地重建股骨近端解剖结构,使应力分布更符合生理要求;2.髋关节表面置换术可最大限度地保留原有骨质和生理结构,使患者术后关节活动度的恢复更接近于正常水平;3.保留较多骨质,增加关节稳定性;4.未破坏骨髓腔,为二次翻修提供便利,无碎屑诱发的骨溶解,假体不会发生无菌性松动。相关临床资料报告关节优良率为94.4-99.7%。但是全髋关节表面置换的并发症也不容忽视,常见的并发症包括股骨颈骨折,股骨颈狭窄,血清铬钴金属离子的上升,下肢短缩跛行,腹股沟区持续疼痛及肿块的形成。据相关研究资料表明,股骨头缺血性坏死在全部髋关节置换术的患者中所占的比例是5%-12%。选择适合患者、正确放置假体、合理使用骨水泥、术中导航技术及术前模拟手术等,可明显降低术后并发症的发生率或减少并发症的危害。当前认为全髋关节表面置换术最佳的适应症为:骨质良好、股骨头直径与股骨颈直径的比值大于1.2、下肢缩短长度小于1cm、年龄小于55岁的、体重小于82千克的非感染和毁损性髋关节疾病患者;传统全髋关节表面置换的术前影像学准备为术前常规拍摄骨盆正位片及双髋关节螺旋CT扫描,主要从二维平面评估骨质破坏情况、头颈比率、确定假体的大小、及初步评价股骨头塌陷对于髋关节表面置换术后的可能影响。但二维结构很难完全反应病变的真实形态,特别是股骨头塌陷的范围,囊性变和硬化带的量化及术后截骨后骨质保留之间的相互关系未能给予一量化的评估;应用非影像的计算机导航技术可以缩短初学者的学习曲线,术中及时反馈,从而使股骨假体置于最佳位置。但也有其缺点:1.手术时间相对较长;2.红外线参考架术中应该避免碰撞移动,否则需要重新注册。3.解剖标志点选择要准确,否则影响图像匹配精确性。当前国内引进非影像导航系统的医院还少,目前在国内才处于临床摸索阶段,缺乏大样本的系统的临床应用研究,因此很有必要进行相关的技术培训和理论研究,接受这一新的外科辅助理念。随着计算机技术的飞速发展,虚拟现实技术(virtual reality VR)在医学上发挥着重要的作用。在临床上,为了避免直接使用人为制定的手术策略进行手术所带来的巨大风险,目前采取的最好解决方法就是建立一套虚拟仿真系统。虚拟仿真系统基于三维医疗可视化立体模型。对外科手术进行规划和虚拟操作。开展这方面的研究将在精确手术定位、缩短手术时间、提高手术质量等方面带来一系列的技术变革。目前,对于医疗仿真的研究多数集中利用患者的医学影像资料(CT/MRI图像)或数字人(Virtual Human VH)数据库进行人体组织器官的建模,应用数字化三维医学影像交互式控制系统mimics (Materialise’s interactive medical image control system)或3dsmax等软件系统进行手术模拟演练、手术计划制定、手术教学、技能训练、术中引导手术、术后康复等工作。目前虚拟手术模拟系统主要涉及耳鼻颌面外科、矫形外科、神经外科、虚拟内窥镜等方面,临床医生将医学影像数据输入到系统中,将原始图像格式转换为计算机方便处理的格式,并对图像进行减噪、提高信噪比和消除图像的伪影,通过分割提取感兴趣区域或待手术部位,对同一部位不同模态图像进行配准和融合,然后可视化立体结构得到直观的三维立体模型显示。最后调用交互操作程序,对可视化三维立体模型再进行一系列的交互操作(旋转、缩放、平移、切割、测量、组合、以及虚拟假体置入等来实现手术模拟)。目前可视化虚拟手术主要应用于脊柱椎弓根螺钉内固定系统定位、复杂骨折复位及选择个体化内固定器械、全髋全膝关节置换截骨平面的选择等相关研究。目前国内外关于虚拟现实技术应用于客观评估髋关节病变情况及设计个性化的虚拟手术鲜有报道。本研究利用Mimics在数字仿真与三维建模方面的优势,将飞利浦Brilliance64排螺旋CT薄层扫描得到的Dicom原始数据导入Mimics软件中进行三维骨盆重建,对三维骨盆结构(股骨头囊性变,硬化带,及髋臼骨质)进行准确而完整的术前数字化评价;在Geomagic studo 8.0及3dsmax软件中对三维模型进行可视化虚拟操作,明确股骨颈中心定位,截骨平面,假体大小及放置,最大程度的实现手术效果的最优化。第一章基于CT断层图像重建股骨头缺血性坏死三维结构目的:1.快捷、精确的基于CT断层图像重建股骨头缺血性坏死髋关节三维立体结构;2.客观评价病变组织。方法:利用Philips/Brilliance 64排螺旋CT各向同性分辨率0.625mm的薄层扫描技术,基于0.5mm层厚286张股骨头缺血坏死性坏死患者髋关节的连续断层图像,Mimics 10.01软件直读入Dicom格式原始图像,根据阈值设置不同产生不同的蒙罩,每层图像经边缘分割,选择性编辑及补洞处理,去除冗余数据,分别建立髋臼,近端股骨,股骨颈及股骨头病变组织的三维立体结构。将重建好的各部分结构以STL格式导入Geomagic studo 8.0软件进行光滑及配准处理。结果:三维重建的髋关节(包括病变组织)与术前影像学资料,术中所见完全吻合。三维立体结构外型逼真,能够任意角度的旋转及缩放观察,多彩色、透明或任意组合显示,视觉效果较佳,整体清晰、实体感强。通过不同平面的切面可以观察各组件的内部结构关系。并且能对内部结构进行拆分,分离病变组织(囊性变及硬化带),进一步对病变组织进行体积的评估。各组件以STL格式文件导入Geomagic studo和3dsmax软件系统中可进行虚拟仿真操作。结论:Mimics软件根据CT扫描所得的Dicom原始数据能准确重建股骨头缺血性坏死髋关节的三维立体结构,计算病变体积,为患髋术前骨质的客观评价提供了依据。第二章可视化虚拟手术在全髋表面置换术中的应用目的:1.术前选择合适的假体型号(股骨和髋臼假体);2.术中精确的股骨颈中心定位,准确的截骨及最佳位置放置假体,根据全髋关节表面置换的术前数字化评价为髋关节表面置换术中假体位置的放置和手术技术的改进提供技术支持。方法:假体大小测量:在3dsmax软件中导入以STL格式保存的三维重建图像。分别于股骨头颈交界处取前后、内外侧的最大直径。前后直径约为44mm,内外侧直径约为40mm(测量过程在Geomagic studo 8.0完成)。因此本虚拟手术选择股骨假体直径为44mm,髋臼假体直径为50mm的假体。股骨颈中心定位:由于股骨颈并非标准的圆柱形或者椭圆柱形,骨头的中心并非股骨颈的中性,本研究取过股骨颈中心且平行于股骨颈的直线与股骨头的交点作为虚拟导针的初步进针点,由于患髋股骨头前外侧明显塌陷,并且积聚大量的囊性变区域,而后内侧骨皮质骨质较好,为了去除更多的囊性变和保留更多的完整骨质,因此进针点向后方平移了3mm。近端股骨虚拟打磨:(1)沿着进针点插入一粗导杆,虚拟平台锉(平行于股骨颈)去除股骨颈近端骨质部分约6mm厚。(2)沿导杆方向用—与股骨颈直径相同(都为44mm)的虚拟桶状锉磨削股骨头至头颈交界处。注意观察股骨颈皮质处是否有切迹的形成,以及计算残余囊性变区域的体积。(3)套上虚拟锥形锉磨削股骨头使股骨头形成一斜角圆柱形,使其外径与股骨头假体内径相匹配。结果:在3ds max v7.0软件系统中,运用布尔逻辑运算系统,模拟全髋表面置换整个手术过程,效果生动、逼真、基本和实际手术操作过程相同(见下图所示)。并且经过虚拟桶状锉磨削股骨头至头颈交界处,可以从前后内外侧清晰可见股骨颈边缘无多余骨赘及切迹形成,形成—有效的股骨截骨面。并可进而观察股骨颈部剩余骨囊肿的区域及计算保留的股骨颈部骨量。结论:可以在3ds max v7.0的三维坐标仪中建立起不同的虚拟手术器械(虚拟平台锉,虚拟桶状锉,虚拟锥形锉),通过布尔逻辑运算系统形成有效的虚拟近端股骨打磨。在整个植入过程中,假体角度的数据始终显示在计算机屏幕上,假体的位置以虚拟的形式实时更新显示,使术者对假体的位置十分清楚,能够以量化的形式精确地植入假体。本文通过可视化模拟的截骨技术,也可实现在尽量保存股骨颈部骨量同时,最大程度的去除股骨颈部骨囊肿体积;最大程度的实现手术效果的最优化。

【Abstract】 Advanced stage of avascular necrosis of the femoral head,congenital hip dysplasia,slipped femoral epiphysis,and ankylosing spondylitis will induce severe hip pain and dysfunction, for such advanced hip joint disease,the better treatment is carried out total hip arthroplasty.For a long life expectancy,better bone conditions, more activity volume,in the future faced by overhaulinged,the patient will be encouraged to select the hip resurfacing arthroplasty,such as following features:1.HRA can be more precise reconstruction of the proximal femoral anatomy, so that the stress distribution more in line with physiological condition with less stress shield;2.HRA to maximize the preservation of bone mass and physical structure, which made hip activity of the restored closer to normal levels;3.To retain more bone, increase hip stability;4.Not undermine the bone marrow cavity,facilitate the renovation of secondary,non-debris-induced osteolysis,aseptic loosening of prosthesis didn’t occur.Several authors have reported report of the relevant clinical data rate of 94.4-99.7% excellent.However,hip resurfacing arthroplasty complications can not be ignored,common complications include femoral neck fractures,femoral neck narrow, serum cobalt chromium metal ions increasement,lower limb shortening limp,groin area pain and formation of lumps.According to the relevant research data shows that avascular necrosis of the femoral head in total hip arthroplasty in the proportion of patients was 5% -12%. Appropriate patients,correctly placement of prosthesis,rationality use of bone cement,intraoperative navigation technique and preoperative simulation of surgery can significantly reduce the incidence of postoperative complications or reduce the complications of hazards.Current the best indications of hip resurfacing arthroplasty are:good reserved bone,the femoral head diameter and neck diameter ratio greater than 1.2,lower limb shorten the length less than 1cm,younger than 55 years of age, body weight less than 82 kilograms and non-infection hip disease.Traditional Preoperative ready for HRA included X-ray of pelvis and CT-scan,mainly assessment of bone destruction,head and neck ratio,selection the size of the prosthesis,and a preliminary assessment of femoral head collapse from the two-dimensional.But the two-dimensional structure is difficult to complete reflect the true information, especially the scope of the femoral head collapse,area of cystic and hardening with quantitative and postoperative bone area after osteotomy.application of non-images, computer-guided. technique can shorten the learning curve for beginners, intraoperative feedback in a timely manner,so that femoral prosthesis placed in the best position.But also there are some disadvantages:1.Operative time was relatively long;2.Infrared reference frame should be avoided collision and move,otherwise need to re-register.3.Anatomical landmark point must be accurate,otherwise affect the image matching accuracy.Currently,hospital’s introduction of non-imaging navigation system is also less present in our country with clinical exploratory stage,and lack of a large sample of clinical application of the system,it is necessary to conduct related technical and theoretical research, acceptance of this new surgical concept.With the rapid development of computer technology,virtual reality technique(virtual reality VR) in medicine is playing an important role.Clinically,in order to avoid direct surgical surgery strategies generating enormous risk,and currently the best solution is to establish a virtual simulation system. Three-dimensional virtual simulation system is based on three-dimensional model of medicine to carry out Surgical planning and virtual operations.To carry out research in this area in accurate positioning during operation,shorter operative time and improve the quality of surgery to bring about a series of technological change.At present,the majority of the medical simulation study focused on making use of patient medical image data (CT/MRI images) or people (Virtual Human VH) database to construct the modeling of human tissues and organs,the application of Materialise’s interactive medical image control system(mimics) or 3dsmax software systems in surgical simulation,surgical plan,operation instruction,skills training,postoperative rehabilitation and so on.Currently virtual surgery simulation system is mainly involved in maxillofacial surgery,orthopedic surgery,neurological surgery,virtual endoscopy,etc.medical image data is entered into the correlated system,the original image will be diverted into more facilitated computer format,with image noise reduction,improve signal to noise ratio and the elimination of image artifacts,by extracting a region of interest(ROI),spliting surgical site and modality image registration or fusion,visualization of three-dimensional structure has been an intuitive show.With interactive procedures,the visualization of three-dimensional model can be conducted a series of interactive operations (rotation,zoom,pan,cut, measure, mix,and the virtual implant surgical placement,etc.to achieve the simulation).Visualization of virtual surgery is currently the main application of spinal fixation system for positioning,complex fractures or selection of individual internal fixation,total hip replacement and total knee osteotomy. Research on the objective assessment of the hip and design personalized virtual surgery has been reported rarely reported at home and abroad.In this research,we make use of Mimics software in the advantages of digital simulation and three-dimensional modeling to reconstruct 3D model of pelvis by initial data from the Philips Brilliance 64-slice spiral CT scans,and appraisal three-dimensional pelvic reconstruction exactly,which included femoral head cystic area,hardened area,and the acetabular bone;The 3D model will be input into Geomagic studo 8.0 and 3dsmax software to carry out visible virtual operation,to implement clear neck center position,accurate osteotomy plane,suitable prosthesis size and optimization component localization,we can achieve the greatest degree of optimization with Preoperative visible simulation surgery. Chapter one:Reconstruction of avascular necrosis of the femoral head 3D model based on CT imageObjective:1.To investigate an easier and more precise method of reconstruction of the hip 3D model based on CT Images;2.To assess the diseased tissue of hip.Methods:In advantage with the 0.625 mm isotropous imaging resolution scan Technique of Philips/Brilliance 64 rows spiral CT,we got 286 layers of2-Dimensional CT pictures of hip atlas and axis.Mimics 10.01 read these original Dicom’ format pictures in and extracted each deck contour line automatically after defined bone tissue threshold.Every layer of picture would be processed by parting edge of it,editing it selectively,repairing the hole of it and removing the redundant data from it,namely establishment 3D model of acetabulum,proximal femur,femoral neck,and femoral head lesions.All rebuilded tissue will be Input into Geomagic studo 8.0 software and equipped with quasi-smooth handling as STL format.Results:The three-dimensional reconstruction of the hip (including the diseased tissue) and the preoperative imaging data, intraoperative findings fit together well.It has lifelike appearance,can be arbitrarily rotated or zoomed and displayed with colorful,transparent or arbitrary combination of image.Therefore,it has a better visual effect.Through this model,we can observe the inner structure relation of each component from any plane of different cross-section.The internal structure can be split,separated diseased tissue(cystic change and hardening belt).wo can objectively assess the diseased tissue of hip.STL format file put into Geomagic studo and 3dsmax software system can implemented virtual simulation surgery.Conclusion:Mimics software,according to the original data Dicom from CT scan obtained an accurate reconstruction of 3D model of hip joints in patients,wo can calculate diseased tissue volume,providing objective evaluation hip bone. Chapter two:Application of visible simulation surgery in the hip resurfacingObjective:1.To select the appropriate prosthesis type(femoral and acetabular prostheses);2.Exactly Centralization neck of femur,precise osteotomy and component localization,to provide preoperative digital Evaluation of hip and improve of surgical technique.Methods:The prosthesis size measurements:Three-dimensional reconstruction model of hip was input into the 3dsmax software as STL format.the diameter of Femoral neck of maximum and minimum were,44mm,40mm,respectively (measurement process in geomagic8.0),so femoral prosthesis size was 44mm.Ⅰ.Centralization neck of femur:As the femoral neck was not a standard cylindrical or oval cylindrical, the center of femoral neck bone was not Consistent with femoral head,in this research study a guide pin was inserted into the center of femoral neck center In parallel with the femoral head,because the apparent ipsilateral anterolateral femoral head collapse,the accumulation of large areas of cystic degeneration,and then the medial cortical bone better.to remove more of the cystic tissue and retain more the integrity of bone,so guide pin shift to the rear 3mm.Ⅱ.Virtual Osteotomy:(1) Along the direction of guide pin,virtual platform rasp remove approximately 6mm thick bone from the proximal femoral neck.(2)virtual barrel rasp of diameter was 44mm,the proximal femur could be polished by barrel barrel rasp to the junction of the head and neck.To observe whether there wre some notchs at the femoral neck cortex,and calculate the volume of the residual areas of cystic degeneration.(3)Virtual cone-shaped rasp the femoral made femoral head match femoral prosthesis.Results:In 3dsmax v7.0 software system,by Boolean logic operation system,simulation of process of hip resurfacing,the effect was vivid,lifelike.surgeon could implement clear neck center position,accurate osteotomy plane,suitable prosthesis size and optimization component localization.Through the virtual grinding process was displayed on the screen.Conclusion:Different virtual surgical instruments were established in the 3dsmax v7.0(virtual platform rasp,virtual barrel rasp,Vrtual cone-shaped rasp),to carry out virtual proximal femoral grinding by Boolean logic operation.Throughout the implantation process,the implant angle data was always displayed on the computer screen,the location of prosthesis was in the form of virtual real-time update the display,so surgeon are very clear of prosthesis position.In this research,visual simulation technology enables the surgeon in trying to reserve more bone mass of femoral neck,removal of cyst area in the greatest degree and optimization component localization.

节点文献中: