腰椎棘突间非融合撑开器的数字化分析及临床应用

【作者】 刘瑞；

【导师】 徐林；

【作者基本信息】 北京中医药大学 ， 中西医结合临床， 2011， 博士

【摘要】 脊柱融合术被认为是治疗腰椎退行性疾病的经典术式,但融合后会存在许多潜在的并发症,包括腰椎融合节段活动丧失、邻近节段的退变加速等,鉴于此,学者们不断探索,非融合(动态固定)的理念便产生了。腰椎非融合技术是在保留腰椎节段有益运动的同时适当的固定,避免不利的运动,但不进行节段间融合,通过改变负荷传递,从而减轻腰痛和预防相邻节段退变加速。腰椎棘突间撑开装置作为非融合技术中的一种,具有操作简单,手术创伤小,容易被医生和患者所接受,但作为一项新的脊柱外科技术,目前国内对腰椎棘突撑开系统相关基础和临床研究相对较少。但各种非融合棘突间撑开系统是否适合国人特点,植入人体后对脊柱生物力学的影响程度缺乏深入、系统的研究。本研究从国人腰椎棘突间区域的解剖学特点出发,并以Wallis系统作为棘突间撑开装置的代表器械,对Wallis系统进行生物力学及早期的临床应用研究。第一部分腰椎棘突及其间隙的解剖学测量目的：利用三维重建技术为棘突间撑开器的设计、优化、国产化及临床应用提供解剖学依据。方法：选取50例志愿者采用连续螺旋CT断层扫描胸12-骶1,将获得图像导入Materialise Mimics10.01软件,采取轮廓和区域增长分割出腰椎骨组织采用表面遮盖显示法进行三维表面重建,选择去除椎旁组织的最佳三维角度,由同一名研究者选择适合测量的图像进行测量,测量：棘突厚度、棘突长度、棘突间距。测量各解剖结构时,连续测量3次,取其均值。数据进行正态性检验、t检验。结果：(1)棘突厚度：一般每个腰椎的棘突厚度均前部>后部>中部,下缘>中央>上缘。但L5较特殊,棘突中部和后部的中央厚,上、下缘薄。相邻上位腰椎棘突下缘厚度大于下位腰椎棘突上缘厚度。(2)棘突长度以L3最大,男性：上缘(26.62±2.98)mm,中央(25.59±2.33)mm,下缘(22.73±2.40)mm；女性：上缘(23.76±2.47)mm,中央(24.49±2.48)mm,下缘(19.70±2.49)mm；男女均以L5最小。(3)棘突间距：男性以L2-3最大,而且向下依次减小,且前部>中部>后部。前部(10.39±2.7 0)mm,中部(11.15±2.20)mm,后部(9.35±2.17)mm。女性以L1-2最大,而且向下依次减小,且前部>中部>后部。前部(10.32±2.10)mm,中部(12.18±2.58)mm,后部(10.80±2.43)mm。男女均以L4-5最小。结论：棘突间距从上向下逐渐减小,且前部>中部>后部,在矢状面棘突间隙呈前高后矮的楔形。棘突长度以L3最大,L5最小。棘突长度均上缘>中央>下缘,相邻上位腰椎棘突下缘长度<下位腰椎棘突上缘长度。棘突厚度前部>后部>中部,且下缘>中央>上缘。相邻上位腰椎棘突下缘厚度>下位腰椎棘突上缘厚度。本研究利用三维CT重建技术初步获得了国人腰椎棘突及棘突间隙的解剖学参数,为适合国人特点的腰椎棘突间撑开器的设计和临床应用提供了解剖学数据。第二部分Wallis腰椎非融合系统有限元模型的建立及分析目的：构建Wallis腰椎非融合系统有限元模型,分析Wallis腰椎非融合在腰椎不同生理运动情况下的应力分布,为临床应用提供生物力学基础。方法：选取8例志愿者采用连续螺旋CT扫描,将获得的断层Dicom格式图像,导入Materialise Mimics10.01软件,定义骨组织阈值、提取各层面轮廓线、图像边缘分割、三维重建L4,5椎体及椎间盘三维模型,对模型加载,计算L4.5节段前屈、后伸、侧屈和旋转运动的活动范围,并将结果与文献结果进行对比,验证模型有效性。将重建的模型以.st1格式保存；在AutoCAD 2009软件中建立Wallis系统模型,以.st1格式保存,导入Materialise 3-Matic4.3软件,进行三角面片优化,将重建的Wallis模型按标准手术模式与腰椎模型拟合,导入Abaqus6.9软件进行赋值和网格划分,生成有限元模型,并进行分析腰椎前屈、后伸、侧屈及旋转运动时Wallis腰椎非融合系统的应力变化。结果：完成腰椎三维有限元模型的建立,模型共有233438个单元,48174个节点,通过验证模型有效,建立了Wallis系统的三维有限元模型,共有11857个单元,3398个节点,将二者拟合,模型共有245295个单元,51572个节点,重建的三维模型可以精确的模拟Wallis非融合系统固定情况。。通过应力云图显示前屈、后伸、侧屈及旋转运动下Wallis系统的应力分布情况,本模型说明Wallis系统参与了腰椎不同方向的活动,与腰椎很好地匹配,顺应了腰椎的运动,位于上下棘突之间的部分应力较大,且与下位椎体棘突相接触部分的应力最高。结论：应用CT扫描技术及Mimics软件能直接与Abaqus软件进行对接,并能根据CT值直接赋值使Wallis腰椎非融合系统有限元模型的建立更加快捷、精确,Wallis棘突间撑开器植入后可分担椎间盘应力和小关节压力,Wallis系统本身和棘突应力升高,有棘突骨折及植入物疲劳性断裂的可能性。第三部分Wallis棘突间撑开系统治疗腰椎退行性疾病的初步临床观察目的：通过对Wallis腰椎非融合系统治疗腰椎退行性疾病的临床观察,探讨Wallis系统治疗腰椎退行性疾病的初期疗效。方法：选取自2007年8月-2008年10月在东直门医院单独采用Wallis棘突间动态稳定系统或结合固定融合方法治疗腰椎退行性疾病的病例31例,均获临床随访,随访时间18-40月,每例均记录Wallis手术时间、术中出血量,术前、术后不同时期采用0DI功能障碍指数、JOA评分、VAS评分和中华医学会骨科分会脊柱外科组腰椎手术疗效标准评估手术疗效,随访有无Wallis系统相关并发症及疗效。结果：所有病例均按术前计划顺利完成手术,单独应用Wallis系统治疗的患者19例：手术时间(75±22)min,Wallis系统植入时间(23±8)min,术中平均失血量(150±60)ml;Wallis系统与固定融合结合的手术患者12例：手术时间(140±45)min,Wallis系统植入时间为(18±6)min,术中平均失血量(350±100)m1。所有患者切口愈合好,按期拆线。所有病例术中均未发生棘突骨折、神经损伤、内置物断裂、感染等并发症。术后随访18-40个月,平均26.8个月,所有患者术后症状和体征均有不同程度改善：术前、术后2周及末次随访疼痛VAS评分分别为：7.65±1.30、3.85±1.53、3.75±1.51,JOA评分分别为：13.50±3.25 24.51±2.22、23.95±2.69,ODI评分分别为：40.26±3.42、22.05±4.30、22.31±2.89。术后2周及末次随访VAS、JOA、ODI评分与术前比较差异有统计学意义(P<0.01)；末次随访疼痛VAS、JOA、ODI评分与术后2周比较差异无统计学意义(P>0.05)；随访中所有病例均未发现Wallis系统的移位、松动、断裂,无腰椎后凸畸形,棘突骨折,症状复发等情况；末次随访患者对手术的整体满意度为92.3%,结论：结合临床疗效及影像学随访观察,Wallis系统治疗腰椎退行性疾病的短期疗效满意,目前可作为治疗手段的另一种选择。其长期疗效还有待进一步临床随访观察。更多还原

【Abstract】 BackgroundTraditional spinal fusion surgery is considered as classic surgical procedures to treat lumbar degenerative disease. All sorts of potential complications after spinal fusion, including the loss of activities among the lumbar fusion segment and the acceleration degeneration of adjacent segment. In view of these, scholars have been exploring the new concept of non-fusion technique which is called dynamic fixation system, it can maintain the mobile motion of the spine segment. The purpose is to change the way of mobile segment bearing load, to control the intersegmental abnormal movement, which means that dynamic fixation could reduce pain and prevent degeneration of adjacent segments by means of controlling abnormal movement. However, Interspinous process distraction device (IPD) is a non-fusion technology as a new spinal surgical technique, Its long-term effect is uncertain. And whether they are suitable for Chinese and the influence on the spinal biomechanics post-implanting are still uncertain. In this study, according to the anatomical features of interspinous region of lumbar vertebrae in Chinese men, we would like to choose and assess Wallis’s effect on implanted by the biomechanical and the early clinical outcome of Wallis system.Part I Anatomical measurement of the lumbar spinous process and the gapObjective:To supply anatomical basis for the design, optimize-localize and clinical application of interspinous internal fixation instrument of lumbar vertebrae by the technique of three-dimension (3-D)reconstruction. Methods:Fifty volunteers were subjected to CT scanner from T12 to S1 level. CT scan images were imported into Materialise Mimics 10.01 software. Bone organization threshold, outline and edge were defined and edited selectively,then measurement tools were used to measure the following parameters of lumbar vertebrae by the same researcher:the thickness of spinous processes, the height of spinous processes and the distance between two adjacent spinous processes, All the data were analyzed with the SPSS 13.0 statistical software for test of normality and t test. Results:(1) Lumbar spinous thickness:generally, front part>back part>middle part, inferior border> central> superior border. But L5 is more special, middle part and back part of spinous were thicker than superior border and inferior border. Adjacent upper lumbar spinous inferior borderis thicker than down lumbar spinous superior border.(2) L3 has the longgest spinous, Male:superior border(26.62±2.98) mm, central(25.59±2.33) mm, inferior border(22.73±2.40) mm; Female: superior border(23.76±2.47) mm, central (24.49±2.48) mm, inferior border (19.70±2.49) mm; L5 has the shortest spinous.(3) spinous spacing:in male, L2-3 has the biggest space, and minish in turn down, all of them is front part>middle part>back part.Front part (10.39±2.70) mm, middle part(11.15±2.20) mm, back part (9.35±2.17) mm. In female:L1-2 has the biggest space, and minish in turn down,all of them is front part>middle part>back part,too.Front part (10.32±2.10) mm, middle part (12.18±2.58) mm,back part (10.80±2.43)mm.L4-5 has the smallest space.Conclusion:spinous decreased gradually from top down,front part>middle part>back part, in Sagittal plane spinous space is wedge-shape. Spinous maximum length by L3, L5 is minimum. Spinous lengths:superior border>central>inferior border, adjacent upper lumbar spinous length (position inferior with length of lumbar spinous. Spinous thickness: front part> back part>middle part. This study used the thickness three-dimensional CT reconstruction technique has been obtained compatriots lumbar spinous and spinous clearance anatomy parameter for americans, for the lumbar spinous characteristics between the design stretched and clinical application provides anatomical data.PartⅡEstablishment and analysis of finite element model of Wallis non-fusion system for human lumbarObjectiver To establish finite element model and analyze the movement under different physiological stress distribution of Wallis non-fusion system, which provide a foundation of biomechanics for clinical application. Methods:Eight volunteers were subjected to CT scanner. CT scanning images were imported into Materialise Mimics 10.01 software. Bone organization threshold, outline, edge were defined and edited selectively. Three-models of L4.5 lumbar and its disc were reconstructed and saved in STL format. The merging models then transformed into Abaqus 6.9 software for pre-processor, then analyzed the rotation range of activities of lumbar flexion, extension, lateral bending and rotation of L4/5 lumbar segment, and then the results were compared and verified the model validity with the literature results. These models then imported into Materialise 3-Matic 4.3 software for re-meshing. Three-dimensional model of Wallis system were established using auto CAD 2009 software, then established with L4.5 models. The merged models then were transformed into Abaqus 6.9 software for pre-processor, then analyzed the stress changes of lumbar flexion, extension, lateral bending and rotation of lumbar Wallis non-fusion system. Results: Three-dimensional finite element model of lumbar was established and verified, then Wallis finite element model was established,It concluded 3398 nodes and 11857 elements, then merging with L4、5 models. It concluded 51572 nodes and 245295 elements, A realistic appearance and calculation accuracy 3D finite element model of Wallis and L4.5 lumbar were established. Then the stress changes of lumbar flexion, extension, lateral bending and rotation of lumbar Wallis non-fusion system were analyzed. Through the stress contour showed that:Wallis system was involved in the activities of lumbar spine in different directions, a good match with the lumbar spine Wallis system conformed to the four conditions the movement of lumbar spine, located between the upper and lower spinous part of the stress is more concentrated, and the vertebral spinous process with the lower part of the stress of contact with the highest. Conclusion: Applications of sophisticated CT scanning technique, the CT scanner images, Mimics software directly dock with Abaqus software can directly assign values, which make the establishment of three-dimensional finite element model of Wallis and L4、5 lumbar faster and more accurate. The finite element model was validated and could be used on biomechanics test. After surgery fixed with Wallis system, Wallis interspinous distraction device can share the stress of the small joints and the disc. The stresses of Wallis system and spinous processes were increased, and the risk of fracture of spinous process is increased accordingly. PartⅢPreliminary evaluation of Wallis interspinous process distraction device in lumbar degenerative diseaseObjective:To explore the efficiency of the Wallis non-fusion system in the treatment of lumbar degenerative disease by clinical observation. Methods:Between August 2007 and October 2008,31 patients of lumbar degenerative conditions were treated alone by Wallis interspinous dynamic stabilization system or a combination of fixed-fusion cases in Dongzhimen Hospital, Beijing, China. Clinical follow-up was done for 18-40 months respectively after the operation,The time and blood loss of Wallis system operation were recorded, The curative effect was evaluated by ODI dysfunction index, JOA score, VAS score and the Chinese Medical Association Orthopaedic Section of lumbar spinal surgery group standard assessment surgery, The early effect and complications associated with Wallis posterior dynamic lumbar stabilization were recorded. Results:According to surgical planning in all cases the successful completion of surgery, alone Wallis system in the treatment of 19 patients, The average operation time was (75±22) min, The average time of Wallis system implanting was (23±8) min, the average intraoperative blood loss volume was (150±60) ml; Wallis system fixation and fusion surgery with 12 patients, The operation time was (140±45) min, the average Wallis system implantation time was (18±6) min, The average intraoperative blood loss was (350±100) ml. Good wound healing in all patients, schedule stitches. All patients did not occur in the spinous process fracture, nerve damage, implant rupture, infection and other complications Were followed up for 18-40 months, mean 26.8 months, all patients had varying degrees of symptoms and signs of improvement:before and after 2 weeks and the final follow-up VAS pain scores were:7.65±1.30,3.85±1.53,3.75±1.51, JOA scores were:13.50±3.25 24.51±2.22,23.95±2.69, ODI scores were:40.26±3.42,22.05±4.30,22.31±2.89. After 2 weeks and the final follow-up VAS, JOA, ODI score compared with the preoperative difference was statistically significant (P<0.01), the last follow-up pain VAS, JOA. ODI score and after 2 weeks no significant difference (P<0.05), follow-up of all cases were not found in the Wallis system, shift, loosening, fracture, no lumbar kyphosis, spinous process fracture, recurrence of symptoms, etc. The last follow-up of patients overall satisfaction with surgery degree was 92.3%. Conclusion:Combination of clinical and imaging follow-up observation, Wallis system of short-term treatment of lumbar degenerative disease satisfactory outcome, the current can be used as an alternative treatment. The long-term efficacy remains to be further clinical follow-up observation.更多还原