Posterior discectomy for the treatment of lower thoracic disc herniation

<正>Objective To evaluate the therapeutic effect of posterior laminectomy and transfacet discectomy combined with interbody fusion and segment fixation for the treatment of lower thoracic disc herniation.Methods From June 2000 to June 2010,36 cases     

非线性三维有限元法分析腰椎间盘退变

目的 探讨椎间盘退变对腰椎活动节段生物力学的影响.方法 采用新型的基于CT图像的CAD建模方法精确建立L4-L5运动节段的三维非线性有限元模型,并通过改变椎间盘材料特性和椎间盘高度等参数,建立正常椎间盘模型和轻、中、重度椎间盘退变模型,分别对4种有限元模型进行生物力学测试,比较4种模型之间刚度、髓核内压、后部结构力、纤维环基质最大应力的差异,并比较椎体、终板的应力分布变化.结果 各种载荷条件下,退变椎间盘模型刚度均与正常椎间盘模型不同,其中轻度退变模型刚度小于正常模型,而中度退变模型和重度退变模型刚度大于正常模型,且重度退变模型刚度大于中度退变模型;与正常模型比较,轻度退变模型的后部结构力略有增大,而中度退变和重度退变模型的后部结构力逐渐减小;随着椎间盘退变程度的增加,髓核内压逐渐减小,纤维环基质最大von Mises应力渐行性增大,各指标在5种载荷下表现一致;随着椎间盘退变的加重,椎间盘承载向纤维环分散,椎体、终板外缘出现应力集中现象.结论 椎间盘退变可导致腰椎活动节段刚度改变,轻度椎间盘退变引起腰椎刚度下降,而中、重度椎间盘退变时腰椎刚度增加;椎间盘退变时腰椎间盘承载与腰椎后部结构力呈现负相关变化;退变椎间盘的承载模式发生改变,椎间盘、椎体、终板应力分布存在向外周扩散的趋势.     

Biomechanical evaluation of cervical spine instability after multiple level laminectomy.

Four fresh human cervical spine specimens (C2-T1) were tested both intact and with C5-C6 laminectomies to evaluate the biomechanical effects of multiple level laminectomy. The loads applied to the specimens were physiological and clinically relevant motion patterns were simulated. The results showed that C5 vertical displacements increased by 83.33% in axial compression, 168.75% in flexion, 106.09% in extension, and 35.14% in left bending after C5-C6 laminectomies compared with intact specimens. The increased rates of C6 vertical displacements after laminectomy were slightly lower than C5. The anterior horizontal bulging of C5-6 discs increased by 29.69% in axial compression, 13.86% in flexion, 61.79% in extension, and 13.40% in left bending after laminectomy. The rotational angles of whole specimens had an increase of 15% after laminectomy. The strains in the anterior vertebral bodies and posterior laminae near the articular processes of C5 and C6 were increased significantly after laminectomy. The data indicated that multiple level laminectomy can lead to biomechanical instability of the cervical spine.

     

椎体后凸成形术后骨水泥椎间盘渗漏对邻近节段力学影响的有限元分析

目的 探索椎体后凸成形术(PKP)术后骨水泥椎间盘渗漏对相邻椎体的力学影响,探讨相邻椎体继发骨折的病因.方法 利用MIMICS软件用有限元方法对1例T12压缩骨折PKP术后出现椎间盘骨水泥渗漏的患者手术前后CT图片进行预处理,后导入ABAQUS软件中建立T10-L2的三维有限元模型,设置0.3、1.0、4.0 Mpa 3种轴向载荷进行生物力学分析,观察不同载荷下模型整体及各部分的Von Mises应力,重点评价骨水泥椎间盘渗漏对骨折相邻椎体的力学影响.结果 成功建立了PKP术后骨水泥椎间盘渗漏的手术前后三维有限元模型,当轴向压力以0.3、1.0、4.0 MPa增加后,椎间盘、软骨终板和椎体整体的应力也成比例增加.PKP术后脊柱胸腰段各部位的应力开始重新分布,增强椎体(T12)的上、下终板应力增强区域范围增加;相邻椎间盘(T11-12、T12-L1)及相邻终板(T11下终板、L1上终板)的应力增强区域增加;T12相邻椎体(T11、L1)所受最大应力显著增加,但是远端椎体(T10、L2)的最大应力明显减少.结论 PKP术后骨水泥椎间盘渗漏引起上下相邻椎体继发骨折的并发症可能和生物力学行为的改变密切相关.

Abstract：

Objective To explore the biomechanical effects on adjacent vertebra of thoracolumbar osteoporotic vertebral compression fracture (OVCF) after percutaneous kyphoplasty (PKP) with cement leakage into the disc by using finite element analysis. Methods T10-L2 segment data were obtained from computed tomography (CT) scans of an elder female with single T12 OVCF undergoing a cement leakage into the T1 2-L1 disc after PKP. A three-dimensional finite element Model of thoracolumbar spine (T10-L2)was built in the Mimics and the ABAQUS software. The stress on annulus fiber, nucleus pulposus, endplate and facet joints under axial pressure (0. 3, 1.0, 4. 0 MPa) were analyzed. Results The 3D finite element after percutancous kyphoplasty (PKP) with cement leakage into the disc may be strongly related with the changes of biomechanical effects on adjacent vertebras of thoracolumbar OVCF. Models of thoracolumbar OVCF before and after PVP with a cement leakage into the T12-L1 disc were successfully established. The stresses increased with a rising axial pressure in the model of cement leakage into the disc after PVP, the stress augmentation scope on adjacent end plates ( T11 low plate & L1 top plate) and intervertebral disc (T11-12 & T12-L1 ) increased. The maximal Von Mises stress on adjacent vertebras (T11 & L1 ) increased while but the maximal Von Mises stress on end vertebras (T10 & L2) decreased. Conclusion Postoperative adjacent vertebral fracture.     

腰椎间盘退变后应力变化的有限元分析

目的 利用有限元分析方法,评估腰椎间盘退变后的生物力学变化.方法 利用MIMICS软件对正常腰椎的CT图像进行预处理后,导入ABAQUS软件建立正常椎间盘L3～L4节段的三维有限元模型.通过改变椎间盘退变后对应的材料属性,建立退变椎间盘L3～L4节段的有限元模型.对模型施加0.3 MPa均布轴向压缩载荷,比较正常和退变椎间盘的纤维环、髓核、软骨终板、关节突关节的应力.结果 与正常椎间盘比较,退变椎间盘的应力分布发生改变,纤维环周边承受较大应力,髓核的压应力明显降低,软骨终板的应力集中在外周偏后;关节突关节面的应力明显增大.结论 有限元方法可以直观地观察椎间盘退变对腰椎的影响,是对临床研究的必要补充.     

Normal and degenerated rabbit nucleus pulposus cells in in vitro cultures: A biological comparison

This study examined the biological characteristics of normal and degenerated rabbit nucleus pulposus (NP) cells in vitro in order to provide seed cells for intervertebral disc (IVD) tissue engineering. A total of 8 adult New Zealand white rabbits underwent annulus puncture to establish models of intervertebral disc degeneration (IDD). Four weeks later, normal and degenerated NP cells were obtained. Cell morphology was observed by light and electron microscopy. Cell viability was measured by MTT assay. Cell cycle and expression of extracellular matrix (ECM)-related genes (aggrecan and type Ⅱ collagen) were determined by using flow cytometry and RT-PCR respectively. The growth curve of normal NP cells showed that the cells at passage 4 tended to slowly grow on the fifth day of culture. The density of normal NP cells at passages 5 to 7 was significantly less than that of the first-passage cells 2 or 3 days after seeding (P<0.05). The degenerated NP cells at passage 3 showed slow growth at 4th day. After 5 passages, the degenerated NP cells assumed stagnant growth and the growth seemed to stop at passage 7. The MTT assay revealed that for both normal and degenerated NP cells, the absorbance (A) value at passages 4-7 was obviously decreased as compared with that at passage 1 (P<0.05). Cell cycle analysis showed that the proportion of normal NP cells at G l phase was 65.4%±3.5%, significantly lower than that of degenerated NP cells at the same cell cycle phase with the value being 77.6%±4.8%. The degenerated NP cells were predominantly arrested at G 1 phase and failed to enter S phase. The expression of type Ⅱ collagen and aggrecan was significantly decreased with passaging. It was concluded that normal NP cells possessed good viability and proliferative capacity by the third passage, and they could secrete large amounts of ECM within this period. The normal NP cells may serve as seed cells for IVD tissue engineering.     

Autologous nucleus pulposus transplantation to lumbar 5 dorsal root ganglion after epineurium discission in rats: a modified model of non-compressive lumbar herniated intervertebral disc

Background  Nucleus pulposus of intervertebral discs has proinflammatory characteristics that play a key role in neuropathic pain in lumbar herniated intervertebral disc. One of the most commonly used animal models (the traditional model) of non-compressive lumbar herniated intervertebral disc is created by L4–L5 hemilaminectomy and the application of autologous nucleus pulposus to cover the left L4 and L5 nerve roots in rats. However, such procedures have the disadvantages of excessive trauma and low success rate. We proposed a modified model of non-compressive lumbar herniated intervertebral disc in which only the left L5 dorsal root ganglion is exposed and transplanted with autologous nucleus pulposus following incision of epineurium. We aimed to compare the modified model with the traditional one with regard to trauma and success rate.

Methods  Thirty Sprague-Dawley male rats were randomized into three groups: sham operation group (n=6), traditional group (n=12), and modified group (n=12). The amount of blood loss and operative time for each group were analyzed. The paw withdrawal threshold of the left hind limb to mechanical stimuli and paw withdrawal latency to heat stimuli were examined from the day before surgery to day 35 after surgery.

Results  Compared with the traditional group, the modified group had shorter operative time, smaller amount of blood loss, and higher success rate (91.7% versus 58.3%, P <0.05). There was no decrease in paw withdrawal latency in any group. The sham operation group had no decrease in postoperative paw withdrawal threshold, whereas the modified and traditional groups had significant reduction in paw withdrawal threshold after surgery (mechanical hyperalgesia).

Conclusions  Transplantation of nucleus pulposus onto the L5 dorsal root ganglion following incision of epineurium in rats established an improved animal model of non-compressive lumbar herniated intervertebral disc with less trauma and more stable pain ethology.

     

Biomechanical comparison of interspinous distraction device and facet screw fixation system on the motion of lumbar spine: a finite element analysis

Background A large amount of biomechanical and clinical evidence from previous studies suggest the efficiency of the two different posterior lumber non-fusion methods,interspinous distraction device （ISDD） and facet screw fixation system （FSS）,but the biomechanical comparison of ISDD and FSS has not been thoroughly clarified.Methods In the current study,finite element methods were used to investigate the biomechanical comparison of ISDD and FSS.The range of motion （ROM）,intradiscal pressure （IDP） and the protective effects gained by maintaining disc heights were evaluated.Results The ROM was similar between the two non-fusion methods under static standing,flexion and lateral bending.The FSS appeared to be more effective in resisting extension.At the implanted level L3/4,FSS displayed better results for maintaining and increasing posterior disc heights.At the L4/5 level in extension and lateral bending,FSS was better than ISDD,with comparable results observed in other motions.Comparing the posterior and lateral disc heights,FSS appeared to be more effective than ISDD.FSS also had a minor effect on the inferior adjacent segment than ISDD.FSS was more effective in reducing IDP than ISDD in extension.Conclusion Through the finite element analysis study,it can be seen that FSS demonstrates more beneficial biomechanical outcomes than does ISDD,such as being more effective in resisting extension,maintaining and increasing lumbar disc heights and reducing the inferior adjacent IDP in extension.     

Spinal cord——Interlaminar micro-neurosurgical discectomy in lumbar disk hermiation

Objective To investigate the surgical results of interlaminar microsurgical discectomy in lumbar disk herniation. Methods A study of 36 consecutive patients undergoing microsurgical lumbar discectomy was conducted. The extend of anular deficiency and the presence of disc fragment were determined. The clinical raiological parameters, type of surgery performed, follow-up, were assessed. Results We found that interlaminar disectomy without laminotomy was adequate in 28 cases （78 % ）. Seletive foraminotomy in addition to diseectomy was performed in 17 cases （47 % ）. Patients in the Fragment-Fissure and Fragment-Contained group had the best clinical outcomes, and lower rates of reherniation. Conclusion Interlaminar discectomy without laminotomy is a safe,     

MRI矢状位T2图在腰椎分级中的量化分析

目的利用MRI矢状位T2图(矢状位多回波SE序列T2 mapp Ing),探讨椎间盘髓核和纤维环T2值改变在椎间盘退变中的意义,并以此进行椎间盘分级的可行性和有效性。方法随机选取30位健康志愿者(18男,12女;年龄21~49岁;平均年龄34.1岁),均利用常规FSE序列和多回波SE序列对L3/4、L4/5、L5/S1共90个椎间盘进行MRI矢状位扫描。通过图像后处理进行T2图成像(T2 mapp Ing)并对各椎间盘进行分级;测量椎间盘髓核和纤维环T2值,针对T2值与年龄、椎间盘级别、椎间盘位置之间的关系,进行统计学分析。结果 MRI矢状位T2图分级法中,椎间盘级别随着椎间盘位置的降低而增高,随年龄的增加而增高。髓核T2值随着年龄增大而减低,差异有统计学意义(P<0.05);各级别椎间盘髓核T2均值间差异有统计学意义(P<0.05)。结论 MRI矢状位T2图提供了一个建立在T2值上的椎间盘分级方法,通过对T2图的评估及椎间盘髓核和纤维环T2值的测量,有助于监测椎间盘早期退行性改变以及和相关因素的关系。     

交感神经在腰椎间盘源性疼痛中作用的研究进展

椎间盘病变是引起临床疼痛症状的常见原因。近年来,交感神经在退变腰椎间盘的分布逐步被阐明,腰椎间盘病变累及交感神经在腰椎间盘源性疼痛的发病机制中的作用越来越受到重视。椎间盘退变,髓核外漏会导致神经张入腰椎间盘内及神经炎性反应的发生,这种变化也构成了腰椎间盘源性疼痛的基础。本文就交感神经在退变腰椎间盘的分布及腰椎间盘源性疼痛的发病机制进行综述。     

ULTRASTRUCTURAL INVESTIGATION OF LUMBAR INTERVERTEBRAL DISC ELECTRON MICROSCOPIC OBSERVATION OF NORMAL, PROTRUDING AND RUPTURED DISCS

We studied normal lumbar intervertebral discs of rat, rabbit and man (fetus and adult) by transmis- sion electron microscope. It was found that although the annulus fibrosus was composed of fibrocartilage, the cells in the lacunae of the fibrocartilage showed configuration transition from fibroblasts to notochordal cells. Elastic fibers could be detected in the annulus. Nucleus pulposus contained notochordal cells which may exist singly or in stacks in a loose matrix. In patients with protruding or ruptured lumbar intervertebral discs, the diseased disc material originated from the nucleus pulposus, the superficial stratum of the annulus fibrosus, and the cartilagi nous tissue. Both living and degenerate notochordal cells existed in the nucleus pulposus. In the cartilaginous tissue, chondrocytes showed active secretory function or underwent interstitial growth and degeneration. The cellular component of the superficial stratum of the annulus fibrosus was com- prised mainly of living fibrocartilage cells similar to fibroblasts.     

交感型颈椎病患者的病变颈椎间盘内交感神经纤维分布

目的：探讨交感型颈椎病的发病机制。方法：收集颈椎前路切除的7名交感型颈椎病患者的11个退变的椎间盘作为A组,同时收集8名脊髓型颈椎病患者的生理老化椎间盘12个作为B组,7名颈椎外伤患者的10个正常对照椎间盘作为C组,行组织学检查和神经丝蛋白（neurofilament protein,NF）、神经肽Y（neuropeptides Y,NPY）的免疫组织化学染色检查。结果：交感型颈椎病患者的颈椎间盘在组织学上的显著特点表现为,一条或多条从纤维环外层至髓核的血管化肉芽组织条带区,肉芽组织旁的纤维环内可见增生的透明软骨细胞群落。生理老化椎间盘和正常对照椎间盘表现为年龄相关的改变。免疫组织化学染色显示,交感型颈椎病的颈椎间盘内的神经丝蛋白和神经肽Y阳性的神经纤维分布数量和比例,较正常对照椎间盘和生理老化椎间盘明显增多（P〈0．05）;神经纤维主要分布在伴有裂隙的肉芽组织条带区及裂隙周围的增生软骨细胞群落中。结论：以神经肽Y为递质的交感神经纤维通过椎间盘裂隙中的肉芽组织,向榷闾盘重新长入,可能是交感型颈椎病的发病机制之一。     

腰椎间盘超微结构研究

应用扫描和透射电镜观察了正常和退变腰椎间盘的超微结构。扫描电镜下,正常椎间盘的纤维环胶原呈整齐紧密的分层状平行排列,髓核纤维呈无序状排列;退变椎间盘纤维环仍可见平行排列的规律,但结构较松散,髓核纤维粗细不均。透射电镜下,正常椎间盘可见典型的存活软骨细胞、纤维软骨样细胞和轻度退变细胞;退变椎间盘组织所见细胞大多呈不同程度的退变甚至坏死,活细胞少见。     

腰椎间盘突出症髓核的超微结构与临床对照研究

目的探讨腰椎间盘突出症髓核组织的超微结构与临床的关系。方法应用电子显微镜对56例腰椎间盘突出症患者手术中取出的髓核组织进行观察。评价退变程度与病程、发病年龄、疼痛视觉模拟评分（VAS）以及术后日本矫形外科协会（JOA）评分改善的关系。结果①胶原原纤维发生不同程度的变性、融合、扭结或钙化,胶原纤维束间裂隙增大。斑块状扭结的数量与胶原原纤维的退变程度成正比。②软骨样细胞减少,多呈不同程度的退变、死亡,细胞外周致密颗粒增多,并与其退变程度呈正相关。③弹力纤维数量减少且变性。④髓核退变程度与患者的发病时间、年龄呈正相关,与疼痛视觉模拟评分以及术后JOA评分改善率无相关性。结论胶原原纤维的扭结和致密颗粒的数量是判断髓核退变程度的重要指标,影响髓核的超微因素为发病时间和患者年龄。     

纤维环穿刺法建立兔椎间盘退变模型

目的:拟建立一个有效的可重复的椎间盘退变模型.方法:取健康成年新西兰大白兔40只,体质量2.5~3.0 kg,雌雄不限,随机分为纤维环穿刺组和对照组,每组20只.经腹膜外入路暴露L4/5、L5/6两个椎间隙,采用21号针头从椎间隙侧前方刺入L4/5、L5/6椎间盘的纤维环,深度控制在5 mm.对照组仅分离暴露椎间盘,不做任何处理.术后1、2、4、6、8周每组随机选取4只兔子行MRI、HE染色及Ⅱ型胶原免疫组化观察退变椎间盘的变化.结果:MRI观察发现,纤维环穿刺组术后椎间盘T2信号强度呈持续减弱趋势,椎间隙高度也不断下降.从术后2周开始两组差异有统计学意义(P<0.05).HE染色观察发现,随着时间进展,纤维环穿刺组髓核细胞逐渐减少,8周时组髓核组织几乎完全变性,被纤维软骨组织替代.Ⅱ型胶原免疫组化染色示,纤维环穿刺组Ⅱ型胶原表达随时间呈进行性下降,从术后第2周开始两组差异有统计学意义(P<0.05).结论:纤维环穿刺法可以诱导兔椎间盘缓慢退变,为深入研究椎间盘退变机制及治疗手段提供可靠的动物模型.     

椎间盘内注射碱性成纤维细胞生长因子对大鼠腰椎间盘针刺退变的预防作用

目的: 观察碱性成纤维细胞生长因子（basic fibroblast growth factor, bFGF）对SD大鼠腰椎间盘针刺退变的预防效果。方法： 24只成年SD大鼠随机分为实验组、对照组、空白组,每组8只。实验组在术中透视引导下用27G针头对L4-5,L5-6椎间盘后侧针刺后以微量注射器向椎间盘内注射bFGF 50 μL, 对照组椎间盘穿刺后注射生理盐水50 μL,空白组椎间盘不予穿刺,术后8周3组SD大鼠统一行MRI检查,观察T2加权像腰椎间盘信号强度的改变,以Pfirrmann分级法对椎间盘退变程度进行分级,取出椎间盘行病理学观察。结果： MRI结果显示,术后8周实验组及空白组髓核信号强度明显高于对照组,各组间Pfirrmann评分结果差异有统计学意义（P<0.05）,病理学检查显示实验组及空白组髓核细胞数量无明显改变,纤维排列整齐,对照组髓核细胞数量明显降低,胶原纤维排列紊乱。结论：bFGF注射对于后侧纤维环针刺术后SD大鼠椎间盘的退变有预防作用。