椎间盘移植实验—组织形态学研究

观察了６只猴自体腰椎间盘移植术后不同时期间盘组织形态学变化。结果表明：移植椎间盘高度术后１～３月呈下降趋势，４～６月呈恢复上升趋势。大体形态观察，移植间盘髓核的反光性减弱，呈较粘稠状。光镜下纤维环和终板软骨结构无明显改变，髓核中有部分细胞退变，同时亦有软骨样纤维细胞再生，表明间盘组织对损伤有一定的自体修复能力。组织形态学研究结果表明，猴自体椎间盘移植是可以接受的。     

椎间盘移植的实验研究

本实验研究目的在于：（１）建立间盘移植动物模型，（２）观察椎间盘移植术后不同时期Ｘ线、组织病理学、生物化学和生物力学变化。于１５只猴体上制备自体腰椎间盘移植模型，另有３只猴作为正常生物力学对照。结果表明移植间盘高度术后１～３个月呈下降趋势，４～１２个月呈恢复上升趋势。光镜下纤维环和终板软骨结构无明显改变，髓核中有部分细胞退变，同时亦有成软骨样纤维细胞的再生。术后２～４个月蛋白多糖和含水量呈下降趋势，６～１２个月有恢复；胶原含量２～６个月增加幅度较大，６～１２个月较平缓，其中髓核较纤维环明显。生物力学结果表明术后２个月时移植间盘活动度增大，术后４～１２个月恢复至正常水平。实验结果表明移植间盘在组织病理及生物化学方面有轻度退变倾向，同时又有一定的自我修复能力，生物力学上可满足生理活动功能需要。     

腰椎间盘突出症手法治疗经验

腰椎间盘突出症是临床上常见病、多发病,按摩治疗本病效果良好。椎间盘是由软骨板、纤维环、髓核三部分组成,软骨盘是由椎间盘与上下椎体紧密相连的连片软骨组织。纤维环是构成椎间盘周围部分的一种坚韧的纤维组织,和上下连接软骨板紧密连接。髓核位于椎间盘的中心,稍偏后一点,是一种有水份的半胶体状组织。     

椎间盘细胞组织工程的研究进展

近年来体外椎间盘髓核各纤维环组织细胞培养技术的建立，特别是软骨组织工程研究的不断深入及自体椎间盘细胞移植修复髓核缺损动物实验的初步成功，为退变椎间盘的形态结构与生理功能的完全再生修复带来了希望。利用组织工程学修复退变的椎间盘是具有变革性意义的新的治疗探索。现就椎间盘组织工程学研究中的种子细胞、细胞支架、相关生长因子等方面的研究进展综述如下。     

椎间盘组织工程学研究进展

近年来体外椎间盘髓核和纤维环组织细胞培养技术的建立，特别是软骨组织工程研究的不断深入及自体椎间盘细胞移植修复髓核缺损动物实验的初步成功，为退变椎间盘的形态结构与生理功能的完全再生修复带来了希望。利用组织工程学修复退变的椎间盘是具有变革性意义的新的治疗探索。笔者就椎间盘组织工程学研究中的种子细胞、相关生长因子、细胞支架等方面的研究进展综述如下。     

同种异体椎间盘移植的实验研究

本研究是在自体椎间盘移植实验研究的基础上进一步通过Ｘ线、组织病理、生物学活性、生物化学和生物力学探索异体椎间盘移植是否可存活、功能及其归宿。１２只猴随机分为４组，移植术后３、６、９和１２个月分别处死检测。结果表明移植间盘高度术后下降，但１２个月时仍保持正常高度的６１．４％。光镜下未见明显排斥反应，终板和纤维环结构无明显改变，术后早期可见移植间盘终板软骨增生现象，髓核基质密度增大，成软骨样纤维细胞增生明显。３Ｈ－ｐｒｏｌｉｎｅ掺入较对照组明显增加。术后移植间盘的蛋白多糖和水含量降低，而胶原含量增加。生物力学动态变化表明术后早期移植间盘有失稳趋势，晚期则稳定性恢复。上述结果显示同种异体移植间盘可存活，生化代谢虽有变化但有一定的自限性，形态结构无明显改变，生物力学满足功能需要。     

椎间盘移植实验—生物化学研究

恒河猴１２只，于Ｌ＿（３￣４）行自体间盘移植手术。对术后不同时间移植间盘进行生化分析，测定了间盘组织的水、胶原和蛋白多糖含量变化，结果显示：术后２月蛋白多糖及水含量降低，胶原含量升高，髓核较纤维环变化明显。术后４月蛋白多糖及水含量进一步降低，胶原含量回升，与对照组已无统计学差异，水份和胶原含量较，４月无明显变化。提示：椎间盘移植后虽然在早朝有退变倾向，但在后期这种退变部分恢复。     

同种髓核移植延缓椎间盘退变

自体髓核移植或复合培养的髓核细胞移植延缓椎间盘变性已有试验报道 ,但收集髓核引起供体椎间盘变性 ,KuenTak Suh等利用白兔作为椎间盘供体和受体进行试验 ,检查同种髓核移植是否同样延缓间盘变性以及是否诱导免疫反应 ,通过抽吸髓核制作椎间盘变性模型2周后 ,完整的髓核或髓核细胞被植入 ,然后同空白及正常组对照。接受移植的椎间盘在 16周后用组织学和免疫学检查 ,接受髓核移植的椎间盘发生最小的变性 ,接受移植髓核细胞的椎间盘次之。二者均好于对照组 ,这些发现同免疫染色的 型原旦白的强度有直接的关联 ,同种移植没有发生可见的宿…     

椎间盘髓核组织工程研究进展

1椎间盘生物学和退变椎间盘(intervertebral disc,IVD)是纤维软骨结构,由中央髓核(NP)和周围的纤维环(AF)构成。两个部分由不同细胞分型和细胞外基质构成。髓核细胞是圆形的像软骨细胞一样而纤维环有更多成纤维细胞的狭长的形状。髓核细胞生成的细胞外基质富含蛋白聚糖类(PGs),主要有聚集蛋白聚糖和Ⅱ型胶原。AF细胞可生成大量Ⅰ型胶原但仅有少量的PG或者Ⅱ型胶原。椎间盘是无血管的所以营养成分很难扩散。     

颈椎间盘退行性疾病

颈椎间盘退行性疾病是以颈椎间盘退变为主所引起的一组疾病。因颈椎间盘退变程度不同可分为 :颈椎间盘膨隆、突出、脱出症。表现为颈椎神经、脊髓、血管等受压的症状、体征。1　颈椎间盘解剖与组织成份颈椎间盘位于Ｃ2 ～Ｔ1的两个椎体间。主要由纤维环和髓核两部分组成 ,软骨终板是否属于椎间盘的构成部分 ,各作者认识有分歧。纤维环呈同心圆行层状结构 ,前侧及两侧较厚 ,后侧较薄 ,各层纤维方向不同 ,彼此呈 3 0°～ 60°交角。纤维环的外层和中层为胶原纤维 ,通过夏贝氏纤维附于椎体骺环 ,内层为纤维软骨 ,附于软骨终板上。髓核位于椎间…     

人工腰椎间盘三维有限元模型的建立及其应力分析

目的 研究人工腰椎间盘三维有限元模型的建立及其应力分布。方法 利用有限元软件MSC MARK，建立人工椎间盘及L4-5运动节段的三维模型。并赋予各自生物材料特性，然后模拟腰椎节段的运动，研究人工椎间盘的应力分布。结果 建立了具有相应力学特性人工椎间盘和L4-5运动节段的模型。人工椎间盘的应力分布特点为：（1）在所有的运动状态中，滑动核及盖板的中心部位承受的应力最大，其次为滑动核在运动状态下偏向的部位；（2）滑动核及盖板上表面承受各自的下表面2-3倍的应力；（3）在所有的运动状态中，压缩状态下滑动核和盖板的中心部位承受的应力最大。结论 建立人工腰椎间盘三维有限元模型并进行其应力分析是可行的，结果是可信的。     

Influences of disc degeneration and bone mineral density on the structural properties of lumbar end plates

Background contextImplants subsidence is a frequent complication of interbody fusion, which can result in pain, deformity, nerve damage, and even failure of surgery. The end plates as the interface between implants and the vertebral bodies play a very important role in sharing the compression on the vertebral bodies. The information on the structural property distribution of the end plate and its relationship with bone mineral density (BMD) and disc degeneration will be of great significance for the reduction in implants subsidence and improvement in related operative procedures to increase the success rate of interbody fusion.PurposeTo investigate the structural property distribution of the lumbar end plate; the effects of disc degeneration on the biomechanical properties of the lumbar end plate; and the relationship between the biomechanical properties of the lumbar end plate and BMD.Study designA biomechanical study was conducted in human cadaveric lumbar spine models.MethodsIndentation tests were performed at 24 standardized test sites in 120 bony end plates of intact human vertebrae (L1–L5) using a 1.5-mm–diameter, hemispherical indenter at a speed of 0.2 mm/s. The failure load at each test site was determined using the load-displacement curve. Disc condition was evaluated using a four-point grading scale and bone density was measured using the lateral dual-energy radiograph absorptiometry scans. All end plates were divided into different disc degeneration groups based on the states of the adjacent degenerative discs and BMD groups according to BMD values of the corresponding vertebral bodies. The experimental results were statistically analyzed using the SPSS 15.0 with the disc degeneration and BMD being considered as independent factor, and the failure loads of the superior and inferior end plates were also compared.ResultsThe peripheral regions of lumbar end plates were stronger than the central regions (p<.05), with the posterolateral sites in front of vertebral pedicles being the strongest regions. The inferior lumbar end plates were found to be stronger than the superior lumbar end plates (p<.05). The disc degeneration was negatively correlated with the failure loads of the lumbar end plates (r_s=?0.563; p<.01). With increasing disc degeneration, the decreases of failure loads were nonuniform across the lumbar end plate, and the central region became weak with little strength change on the end plate periphery. The BMD was positively correlated with the failure loads of the lumbar end plates (r_s=0.812; p<.01). The failure loads decreased uniformly across the end plate surfaces as the BMD dropped, and the BMD decrease did not change the structural property distributions of lumbar end plates.ConclusionsPreoperative evaluation of the states of intervertebral discs and BMD of patients is necessary for predicting risks of implants subsidence after interbody fusion. For patients with or without disc degeneration or osteoporosis, the implants should be placed at the peripheral regions, especially the posterolateral sites, to acquire higher mechanical strength to reduce subsidence as much as possible.     

Disproportion of end plates and the lumbar intervertebral disc herniation

Background contextIt is suggested that the shape of the vertebral end plates may play a role in the development of abnormalities in the intervertebral disc. On midsagittal magnetic resonance images of the spine in patients with lumbar intervertebral disc herniation, a notable disproportion frequently exists between the end plates of two vertebrae to which the disc is attached. There is apparently no study in the literature examining possible association of this disproportion with development of disc herniation.PurposeTo determine whether a disproportion between two neighboring vertebral end plates is associated with the presence of disc herniation at the same level.Study designCase-control study.Patient sampleTwo hundred fifty patients with primary lumbar disc herniation in the case group and 250 age- and sex-matched normal individuals in the control group.Outcome measuresOn midsagittal sections, the difference of anteroposterior diameter of upper and lower end plates neighboring a herniated (in the case group) or normal (in the control group) intervertebral disc was calculated and expressed as “difference of end plates” or “DEP.”MethodsSubjects with previous spinal surgery, spondylolisthesis, or a significant vertebral deformity were excluded. For the main outcome variable, DEP was calculated at the level with herniated intervertebral disc in the case group, and the mean value was compared with mean DEP at the same level in the controls.ResultsMean DEP was significantly higher in the case group at both L4–L5 (2.45±0.28 vs. 2.08±0.27 mm, p=.02) and L5–S1 (3.32±0.18 vs. 2.51±0.13 mm, p<.001) levels. Similar differences were only marginally insignificant at L2–L3 (1.96±0.14 mm in the cases vs. 1.33±0.15 mm in the controls, p=.07) and L3–L4 (2.17±0.11 mm in the cases vs. 1.55±0.09 mm in the controls, p=.06) levels, with no significant difference at L1–L2 level (1.81±0.10 mm in the cases vs. 1.28±0.09 mm in the controls, p=.12). Each 1 mm increase of DEP at L4–L5 and L5–S1 levels was associated with 53% and 56% elevation in disc herniation risk at the corresponding levels, respectively.ConclusionsDifference of end plate is a significant and probably independent risk factor for lumbar disc herniation.     

Innervation of pathologies in the lumbar vertebral end plate and intervertebral disc

Background contextMagnetic resonance imaging (MRI) has limited diagnostic value for chronic low back pain because of the unclear relationship between any anatomic abnormalities on MRI and pain reported by the patient. Assessing the innervation of end plate and disc pathologies—and determining the relationship between these pathologies and any abnormalities seen on MRI—could clarify the sources of back pain and help identify abnormalities with enhanced diagnostic value.PurposeTo quantify innervation in the vertebral end plate and intervertebral disc and to relate variation in innervation to the presence of pathologic features observed by histology and conventional MRI.Study design/settingA cross-sectional histology and imaging study of vertebral end plates and intervertebral discs harvested from human cadaver spines.MethodsWe collected 92 end plates and 46 intervertebral discs from seven cadaver spines (ages 51–67 years). Before dissection, the spines were scanned with MRI to grade for Modic changes and high-intensity zones (HIZ). Standard immunohistochemical techniques were used to localize the general nerve marker protein gene product 9.5. We quantified innervation in the following pathologies: fibrovascular end-plate marrow, fatty end-plate marrow, end-plate defects, and annular tears.ResultsNerves were present in the majority of end plates with fibrovascular marrow, fatty marrow, and defects. Nerve density was significantly higher in fibrovascular end-plate marrow than in normal end-plate marrow (p<.001). Of the end plates with fibrovascular and fatty marrow, less than 40% were Modic on MRI. Innervated marrow pathologies collocated with more than 75% of the end plate defects; hence, innervation was significantly higher in end plate defects than in normal end plates (p<.0001). In the disc, nerves were observed in only 35% of the annular tears; in particular, innervation in radial tears tended to be higher than in normal discs (p=.07). Of the discs with radial tears, less than 13% had HIZ on T2 MRI. Innervation was significantly less in radial tears than in fibrovascular end-plate marrow (p=.05) and end-plate defects (p=.02).ConclusionsThese findings indicate that vertebral end-plate pathologies are more innervated than intervertebral disc pathologies and that many innervated end-plate pathologies are not detectable on MRI. Taken together, these findings suggest that improved visualization of end-plate pathologies could enhance the diagnostic value of MRI for chronic low back pain.     

自体移植皮片中黑皮素1受体表达与黑色素含量的相关性研究

目的检测黑皮素1受体(melanocortin 1 receptor,MC-1R)及黑色素在不同类型自体移植皮片中的表达,并与自身正常皮肤作对照,初步认识MC-1R在自体移植皮片过度色素沉着中的作用。方法取颈部自体皮片移植术后1年的皮片(包括全厚皮片、中厚皮片及刃厚皮片),以及原供区、受区周围皮肤作为正常对照,采用免疫组织化学方法、银染-丽春红法检测自体移植皮片与正常皮肤中MC-1R表达及黑色素含量。结果MC-1R的表达定位于表皮基底部黑色素细胞、角质形成细胞胞浆;在各类自体移植皮片中均呈阳性表达,皮片愈薄MC-1R表达愈明显;MC-1R在各类移植皮片中的表达与两类正常对照皮肤比较差异均有统计学意义(P<0.01),但两类正常对照皮肤内的表达差异无统计学意义(P>0.01)。不同类型移植皮片表皮中黑色素含量较两种正常对照皮肤均明显增加,且差异有统计学意义(P<0.01);且不同类型移植皮片表皮中黑色素含量的差异亦均有统计学意义(P<0.01),皮片愈薄,黑色素含量愈多;皮片中黑色素含量与MC-1R表达量呈正相关。结论自体移植皮片中黑色素含量与MC-1R表达量呈正相关,MC-1R在自体移植皮片中的高表达能使皮片中黑色素含量增加,在自体移植皮片过度色素沉着中起重要调控作用。     

Anterior lumbar interbody fusion for the management of chronic lower back pain: current strategies and concepts

In a retrospective analysis of two large multicenter clinical studies, 321 patients with degenerative lumbar disc disease were divided into two groups who underwent anterior lumbar interbody fusion using two threaded titanium fusion cages. To determine whether differences in surgical procedures and cage design affect anterior and posterior annular distraction and clinical outcomes, the authors evaluated the clinical and radiographic outcomes of patients treated with a stand-alone ALIF procedure. End-plate preservation techniques were associated with improved anterior and posterior disc space distraction compared with standard end-plate preparation techniques. Similarly, the use of the LT-CAGE device led to greater improvements in restoration of segmental lordosis than did the use of standard cylindric cages. Furthermore, these surgical benefits resulted in improved clinical outcomes as early as 3 months and were maintained over a 2-year follow-up period in patients with improved postoperative disc space distraction and lordosis. Placing cylindric cages in a lordotic or trapezoidal disc space can be accomplished only through asymmetric reaming of the vertebral end plates. In a lordotic disc space, the posterior portion of the disc must be reamed more than the anterior portion. This over-reaming inhibits distraction of the posterior disc space and limits restoration of neuroforaminal height. Reduced reaming and symmetric reaming of the vertebral end plates enable the surgeon to restore anatomic segmental lordosis across the disc space. The tapered cage configuration aids in maintaining segmental lordosis. Anatomic restoration of disc space contours has an impact on a patient's outcome after stand-alone anterior interbody fusion surgery.     

Correlation of end plate shape on MRI and disc degeneration in surgically treated patients with degenerative disc disease and herniated nucleus pulposus.

BACKGROUND CONTEXT: The sagittal profile of the lumbar end plates on magnetic resonance imaging (MRI) has not been investigated in patients with degenerative disc disease (DDD) or herniated nucleus pulposus (HNP). PURPOSE: To examine the shape of the end plates in patients treated surgically for a) low back pain or b) radiculopathy with HNP. Furthermore, to investigate the correlation between end plate shape and disc degeneration on the one, and end plate shape and symptoms on the other. STUDY DESIGN/SETTING: Retrospective review of charts and radiographs. METHODS: The charts, operative reports, preoperative lateral plain radiographs, and MRI scans of 178 patients (85 with low back pain and 93 with HNP) were reviewed. End plate shape was determined on midsagittal MRI cuts, disc degeneration was graded on T2 sequences, and disc height was measured on lateral plain radiographs from L1 to S1 in all patients. Student t-test and chi(2) test were used to detect significant differences and associations. RESULTS: Flat and irregular levels were most common in the lower lumbar spine. The L5/S1 segment was flat in most cases, due to a flat sacral end plate. In DDD patients, disc degeneration on MRI and plain radiographs worsened from concave to flat, to irregular levels. In HNP patients, MRI demonstrated concave levels to be less degenerated, whereas no difference was detected between flat and irregular levels. Disc height of irregular levels was well preserved in HNP patients. Comparing the two groups, flat levels were more degenerated on MRI in HNP patients. Despite similar degrees of degeneration on MRI, concave and irregular levels in DDD patients had lower disc heights. A higher frequency of symptoms was found in flat and irregular levels for both patient groups. CONCLUSIONS: The sagittal profile of end plates in the lumbar spine was described for patients with DDD on the one and HNP on the other. A higher association with symptoms was observed for flat and irregular levels in both patient groups. In DDD patients, disck degeneration on both MRI and plain radiographs increased from concave to flat, to irregular levels. In HNP patients, MRI demonstrated concave levels to be less degenerated, whereas no difference was detected between flat and irregular levels. Disc height of irregular levels was well preserved in HNP patients. Comparing the two groups of patients, flat levels were more degenerated on MRI in HNP patients. Despite similar degrees of degeneration on MRI, concave and irregular levels in DDD patients had lower disc heights. The correlation of symptoms and disc degeneration with the end plate shapes is not definitive evidence of end plate remodeling around degenerated discs. It may simply represent the higher rate of disc degeneration in the lower lumbar levels. This analysis did not provide any hints as to which degenerated discs are more likely to herniated and cause leg symptoms or cause predominantly low back pain.     

Aortorenal arterial autografts: The last two decades

Arterial autografts were introduced nearly a quarter century ago at the University of California, San Francisco and have proven their value for replacement in many demanding arterial problems. Renal artery fibrodysplasia is one of the more common lesions treated with arterial autograft. Arterial autografts that ideally match the renal artery and its branches are procured from the patient's own internal iliac artery. Either straight or branched configuration are available depending on the replacement requirements. In-situ aortorenal autografts are employed for lesions of the main renal artery or primary branches. Ex vivo repair involves temporary nephrectomy, pulsatile hypothermic perfusion and precise micro-vascular repair with unrestricted exposure, illumination, and an unhurried pace with no threat of renal ischemic insult. Autografts are attached proximally to the side of the aorta and distally to the disease-free end of the renal artery or a branch. The technique of arterial substitution for ex vivo repairs are identical except for the additional reanastomosis or reattachment of the renal vein. The arterial autograft exhibits the compliance characteristics which resemble a normal artery, maturation when used in the growing child, and durability essential for the long life span of this treated population. When the objective of a renal artery reconstruction is a normal renal arterial system, then the internal iliac artery autograft is the only choice.     

Intervertebral fixation: clinical results with anterior cages

Anterior lumbar interbody fusion has several clinical advantages over posterior or posterolateral lumbar fusion. Interbody fusion procedures place bone grafts within the disc space at the center of rotation of the vertebral motion segment. The intervertebral area is highly vascular, and the grafts have a wide contact area in the weight-bearing axis of the spinal motion segment. The high rates of fusion associated with the use of the threaded intervertebral fusion cages may be attributed, in part, to the following: (1) removal of the cartilagenous end plates and exposure of bleeding cancellous bony surfaces, (2) reestablishment of anatomic intradiscal height and tensioning of the annulus and ligamentous structures around the disc space, (3) use of appropriately sized implants to engage the peripheral apophysis of the vertebral end plates, and (4) use of autogenous grafts. Threaded interbody constructs provide adequate strength to ensure that no plastic deformation occurs within the maximum physiologic range. Dynamic testing of these implants also has shown that these implants are able to resist cyclic fatigue within typical normal daily physiologic loading. Stability testing has shown that when inserted anteriorly, these devices reduce intervertebral motion and increase spinal stiffness.