【作者】 何飞；

【导师】 李世和； 赵学凌；

【作者基本信息】 昆明医学院 ， 外科学， 2009， 博士

【摘要】 目的:下颈椎椎弓根钉内固定力学优势明显,但操作不当易损伤脊髓和血管,导致严重后果。本文针对这一临床难点,研究建立螺旋CT三维(3D)重建技术辅助下颈椎经椎弓根固定的流程方法,用于术前测量置钉的相关参考指标,依据术前计划更准确地指导置入下颈椎椎弓根钉;通过临床应用该方法,发现其存在的局限性,结合如何克服术中二维(2D)透视监视影像无法立体三维观察的缺点,研究利用当前普及的X线透视和CT设备,建立术中二维X线图像校正术前CT三维模型,重建符合术中现实三维图像的虚拟手术系统,实现术中三维影像引导手术。材料和方法:1.对8具尸体颈椎标本进行螺旋CT扫描,结合下颈椎椎弓根螺钉置入的要求,采用螺旋CT三维重建技术中的容积重建VR和多平面重建MPR技术建立测量流程,对置入椎弓根钉的相关参考指标进行个体化测量,指导标本置钉;2.对8具标本的测量指标进行统计处理,得到下颈椎的解剖形态学参考数据;3.基于螺旋CT后处理技术开展临床患者的术前设计、个体化测量及术后评价,对9例下颈椎多节段椎管狭窄合并创伤性颈椎不稳患者进行椎弓根钉固定及椎管成形术,置入颈椎椎弓根钉44枚,椎管成形42个节段;4.根据螺旋CT三维重建技术辅助标本实验及临床应用的结果,分析螺旋CT三维重建后处理技术平台的局限性,提出该方法在数据准确转化上的困难,以及术中二维透视监视精确性方面的不足;5.结合现有的二维X线透视和螺旋CT设备的技术特点,调研了2D校正3D图像的方法并分析其可行性,阐述研发以术中X线二维图像校正术前CT三维模型,重构符合术中现实的三维模型为核心的脊柱虚拟手术系统引导手术的临床思路,并提出可行的具体方案和技术路线。结果:1.螺旋CT三维重建(MSCT 3D)技术中的VR、MPR技术,可以满足下颈椎经椎弓根固定手术的术前计划需要,MPR轴位、矢状位、冠状位重建,可满足置钉入点、角度的个体化测量需求;2.应用螺旋CT三维重建技术指导临床下颈椎椎弓根钉手术,术后椎弓根的1级穿破为72.7%(32/44),2级穿破为27.3%(12/44),无3级穿破及需要重置螺钉的情况,未发生与器械置入相关的医源性损伤;3.基于螺旋CT后处理技术平台开展术前计划指导手术,在术中如何将测量参数准确转化及如何保证术中实时的准确监测方面存在不足;4.建立基于微机Windows XP2操作系统平台,以Visual studio6.0为开发环境,用面向对象的C++语言结合VTK/ITK和OpenGL软件开发包编制程序,以术中X线二维图像校正术前CT三维模型,重构符合术中现实的三维模型为核心的可视化手术引导体系,将可以更精确地完成术前计划、术中引导手术。结论:1.在现有的螺旋CT三维重建技术指导下颈椎椎弓根钉置入,可以在术前得到解剖结构细节展示、合理的术前设计以及个体化的测量数据,根据测量结果指导操作,手术就不再仅仅是依赖手感和经验,成功置入螺钉将有更大的可能性,同时可节约手术时间,当下颈椎椎弓根有解剖变异、闭塞或较小时该方法的优势对手术更具指导意义。2.螺旋CT三维重建后处理技术主要用于疾病诊断,用于手术计划存在交互性、针对性不足等局限,测量数据的术中转换缺乏量化标准,操作仍需要术中透视监测以修正操作误差,但因颈椎的影像重叠,二维图像缺乏立体视觉,故观察椎弓根钉的位置仍存在准确性不足。3.结合现在较为普及的X线透视设备和螺旋CT设备的技术优势,利用计算机三维重建可视化技术,建立以术中X线二维图像校正术前CT三维模型,重构符合术中现实的三维模型的脊柱虚拟手术系统,用于脊柱手术计划、操作演练、教学,并完成术中的实时引导,扩展其功能将可用于网络,具备较强的实用性及普及性。更多还原

【Abstract】 Objective:Pedicle screws fixed in lower cervical vertebra had been confirmed to have significant mechanical stability,but this method had high risk because of injuries of spinal cord and vascellum around pedicle.To solve the challenge,this study will establish the method of multiple slice computerized tomography(MSCT) scan,three-dimensional(3D) reconstruction assisting lower cervical transpedicular fixation,and measurement program of referenced parameters about lower cervical pedicle screws implant.Based on above experiments,MSCT 3D reconstruction technique was used to assist pedicle screws placement in spinal surgery,clinic experience,therapeutic effect and limitation were recorded and analyzed as well. According to the shortage of the method,combined with the demand on intraoperative 3D image guide,a scheme of spinal surgery simulation system based on 2D/3D image registration was designed to deal with those limitations and accomplish intraoperative 3D image guide.Material and methods:For the pedicle screw insertion in lower cervical vertebra,MSCT scan was performed in 8 cadaveric cervical spines,and VR (volume rending) and MPR(multiplannar reconstruction) technique,which were incorporated within MSCT 3D reconstruction,were studied and used to measure the parameter for guiding pedicle screw insertion.Then all parameters were analyzed by statistic methods,aiming at gaining the parameters of morphologic characteristics in lower cervical spine.When established the method,MSCT 3D reconstruction technique was supplied in vivo.Diagnosis,preoperative individualized design, measurement and postoperative assessment were performed in 9 patients with multilevel degenerative stenosis combining with traumatic instability of lower cervical spine,and cervical pedicle screw fixation(44 pedicle screws) and double-door laminoplasty(42 volumes) had been finished under the plan.According to the analysis of clinic results in first section,the deficiency and limitation of this method was found as well,including the difficulty of data translation and lower ability of real time monitoring.To deal with the limitation and accomplish intraoperative 3D image guide,the simulation system for spine surgery based on 2D/3D image registration,associated with advantages of fluoroscopy and MSCT,was schemed initially,and secondly correlative techniques were study,then achieving the further valuable plans eventually.Results:In vitro,VR and MPR reconstruction techniques of MSCT can satisfy to finish the preoperative plan for transpedicular fixation in cervical vertebra,and the parameters of entry point and angles about pedicle screw insertion can be gained by measurement in axial,sagittal and coronal MPR reconstruction.When the technique was applied in vivo,grade 1 of perforation rate by Richter’s method was 72.7% (32/44) in patients of lower cervical pedicle screw fixation,Grade 2 was 27.3% (12/44),and no cases of grade 3 and iatrogenic damage occurred.By using this method in vitro and vivo,some limitations had been found,which included lower abilities of translation from measurement data,and accuracy of 2D imaging monitor from intraoperative fluoroscopy.To deal with limitation of this method,a visualized spinal surgery simulation system has been designed and studied,and the system be based on microcomputer,the platform of Windows XP2,X-ray 2D and MSCT 3D images registration as key technology,the development envioronment on Visual studio6.0 and the program design combined C++ language with VTK/ITK and OpenGL software packages.Conclusions:Through MSCT 3D reconstruction technique assisting lower cervical pedicle screw fixation,preoperative anatomic structural details,reasonable design and individual datum measurement can be obtained.According to the information guiding the procedure,surgeons will not only depend on excellent handling and experiences.The rates of successful screw placement can be improved significantly,and simultaneouly operation times can be shortened.For cases of pedicle mutation,obturation or minor,the method will present more significant advantages.However,because major objective of MSCT 3D reconstruction technique is to assist diagnosis,when used in operation plan,it still has some limitation in lower abilities such as interaction and direction,translation from measurement data,and accuracy of 2D imaging monitor from intraoperative fluoroscopy.So combined with advantages of fluoroscopy and MSCT,to design and establish a visualized spinal surgery simulation system may be a solution.Depending on the simulation system based on 2D/3D medical image registration,intraoperative guide,convenient plan, repeated simulated manipulation and interactive education will be performed in future days.更多还原