Mechanical initiation of intervertebral disc degeneration

STUDY DESIGN: Mechanical testing of cadaveric lumbar motion segments. OBJECTIVES: To test the hypothesis that minor damage to a vertebral body can lead to progressive disruption of the adjacent intervertebral disc. SUMMARY OF BACKGROUND DATA: Disc degeneration involves gross structural disruption as well as cell-mediated changes in matrix composition, but there is little evidence concerning which comes first. Comparatively minor damage to a vertebral body is known to decompress the adjacent discs, and this may adversely affect both structure and cell function in the disc. METHODS: In this study, 38 cadaveric lumbar motion segments (mean age, 51 years) were subjected to complex mechanical loading to simulate typical activities in vivo while the distribution of compressive stress in the disc matrix was measured using a pressure transducer mounted in a needle 1.3 mm in diameter. "Stress profiles" were repeated after a controlled compressive overload injury had reduced motion segment height by approximately 1%. Moderate repetitive loading, appropriate for the simulation of light manual labor, then was applied to the damaged specimens for approximately 4 hours, and stress profilometry was repeated a third time. Discs then were sectioned and photographed. RESULTS: Endplate damage reduced pressure in the adjacent nucleus pulposus by 25% +/- 27% and generated peaks of compressive stress in the anulus, usually posteriorly to the nucleus. Discs 50 to 70 years of age were affected the most. Repetitive loading further decompressed the nucleus and intensified stress concentrations in the anulus, especially in simulated lordotic postures. Sagittal plane sections of 15 of the discs showed an inwardly collapsing anulus in 9 discs, extreme outward bulging of the anulus in 11 discs, and complete radial fissures in 2 discs, 1 of which allowed posterior migration of nucleus pulposus. Comparisons with the results from tissue culture experiments indicated that the observed changes in matrix compressive stress would inhibit disc cell metabolism throughout the disc, and could lead to progressive deterioration of the matrix. CONCLUSIONS: Minor damage to a vertebral body endplate leads to progressive structural changes in the adjacent intervertebral discs.     

椎体成形术治疗隐性骨质疏松性椎体骨折中不同骨水泥分布的临床疗效比较

目的比较椎体成形术治疗隐性骨质疏松性椎体骨折的两种骨水泥分布特点和两者的临床疗效。 方法回顾性收集我院2017年3月至2019年2月采用椎体成形术治疗隐性骨质疏松性椎体骨折的病例资料。根据椎体内骨水泥的形状分为海绵状分布组和团块状分布组,比较两组患者的一般情况、术中状态、术后1天Macnab疗效评价、以及术前和术后2个月的疼痛视觉模拟评分（VAS）和Oswestry功能障碍指数（ODI）。 结果椎体成形术治疗隐性骨质疏松性椎体骨折患者共计130例,其中海绵状分布组62例,团块状分布组68例,两组患者的一般情况差异无统计学意义。①海绵状分布组的骨水泥注射量少于团块状分布组（P<0.01）。②与术前相比,两组患者术后2个月的VAS评分与ODI评分均降低（P<0.01）,并且海绵状分布组的VAS评分与ODI评分低于团块状分布组（P<0.01）。③在Macnab疗效评价方面,海绵状分布组的优秀率95.16%,团块状分布组的优秀率83.82%,海绵状分布组优于团块状分布组（P<0.05）。 结论在椎体成形术治疗隐性骨质疏松性椎体骨折中,与团块状的骨水泥推注方式相比,海绵状的骨水泥推注方式能够减少骨水泥的用量,取得更好的临床效果,值得临床推广。     

Osteoporosis onset differences between rural and metropolitan populations: correlation to fracture type, severity, and treatment efficacy

Osteoporosis is the prevalent cause of fractures in an ever-aging population, with an established correlation between daily activities and way of life. We aimed to delineate differences in onset of osteoporosis, T-score progression, quality of life, and correlation to prevalence, types, and severity of fractures in age-comparable populations of rural and metropolitan habitats in this multicenter, retrospective double-blind study. We evaluated data derived from the medical files of two comparable groups of osteoporotic patients: group A (n = 530, rural area) and group B (n = 171, metropolitan area). Both groups received comparable treatment for osteoporosis. Comparison was performed on the basis of osteoporosis onset, T-score in a maximum of 8 years follow-up, fracture types [American Academy of Orthopaedic Surgeons (AO) categorization], and type of treatment followed. Quality of life was assessed by use of specialized questionnaires. From the minimum 4-year follow-up of all patients included in the research, there was a statistically significant difference in favor of the rural population in all research parameters. Rural populations presented with osteoporosis at a later age than their metropolitan counterparts, exhibiting favorable T-scores with comparable treatments and simpler fractures (AO categorization). Metropolitan habitats and life therein have a deleterious effect on osteoporosis onset and response to treatment. Rural populations are diagnosed with osteoporosis on a later age, with better compliance and improved treatment outcome. Fracture categorization shows increased severity in the metropolitan populace and a suggested correlation between a poor-quality way of life and decreased activity levels.     

The safety and efficacy of vertebroplasty using Cortoss cement in a newly established vertebroplasty service

Vertebroplasty provides an effective means of treating painful vertebral lesions although the majority of the literature relates to vertebroplasty using PMMA cement. The purpose of this study is to assess the safety and efficacy of vertebroplasty using Cortoss, a recently developed bis-GMA resin. Our newly established vertebroplasty service exclusively uses Cortoss cement and has a patient database which is updated on a regular basis using the medical records. To date, there are 34 patients on this database, mean age 66, in whom a vertebroplasty has been performed on 42 vertebral lesions with a mean of 2.2 ml of Cortoss injected into each lesion. The mean duration of follow up was 9.5 months. Eighty-two per cent of patients reported an improvement in their symptoms, while 79% required less analgesia post vertebroplasty. A total of 88.2% experienced no significant complications. In 38% there was an asymptomatic leakage of Cortoss. Four patients (11.8%) experienced significant complications: one asymptomatic PE, one episode of transient radicular leg pain, one generalized rash and one patient suffered retropulsion of the Cortoss due to further vertebral malignancy. Cortoss vertebroplasty provides comparable efficacy and safety to the published literature for PMMA.     

不同振动频率对大鼠椎间盘退变及骨密度影响的实验 研究

目的讨论不同振动频率对大鼠椎间盘退变和骨密度的影响,以及护具对大鼠腰椎间盘退变的保护作用。方法通过检测大鼠振动训练前后骨密度变化,并于振动后收集大鼠椎间盘髓核组织,对髓核组织进行HE染色、免疫组化等研究。结果随着振动频率的提高,大鼠椎间盘细胞凋亡增加,无护具保护实验组大鼠与有护具保护组大鼠比较,TUNEL检测阳性细胞的百分率和阳性颗粒的平均光密度值增高,差异均有统计学意义(P0.05)。而各组大鼠股骨BMD振动前后无统计学意义。结论振动对骨密度无明显影响,随着振动频率的增加,大鼠椎间盘退变程度增加,护具对振动引起的大鼠椎间盘退变有保护作用。     

High- versus low-viscosity cement vertebroplasty and kyphoplasty for osteoporotic vertebral compression fracture: a meta-analysis

Background

To compare high- versus low-viscosity bone cement on the clinical outcomes and complications in patients with Osteoporotic vertebral compression fractures (OVCFs) who underwent percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP).

Methods

PubMed, Embase, and the Cochrane Library were searched for papers published from inception up to February 2021 for potentially eligible studies comparing high- versus low-viscosity cement for PVP/PKP. The outcomes were the leakage rate, visual analog scale (VAS), and Oswestry Disability Index (ODI).

Results

Eight studies (558 patients; 279 in each group) were included. The meta-analysis showed that the leakage rate was lower with high-viscosity cement than with low-viscosity cement (OR = 0.23, 95%CI 0.14–0.39, P < 0.001; I² = 43.5%, P_{heterogeneity} = 0.088); similar results were observed specifically for the disk space, paravertebral space, and peripheral vein, but there were no differences regarding the epidural space and intraspinal space. The VAS was decreased more significantly with high-viscosity cement than with low-viscosity cement (WMD = − 0.21, 95%CI − 0.38, − 0.04, P = 0.015; I² = 0.0%, P_{heterogeneity} = 0.565). Regarding the ODI, there was no difference between high- and low-viscosity cement (WMD = − 0.88, 95%CI − 3.06, 1.29, P = 0.426; I² = 78.3%, P_{heterogeneity} < 0.001).

Conclusions

There were lower cement leakage rates in PVP/PKP with high-viscosity bone cement than low-viscosity bone cement. The two groups have similar results in ODI, but the VAS scores favor high-viscosity bone cement. Therefore, the administration of high-viscosity bone cement in PVP/ PKP could be a potential option for improving the complications of leakage in OVCFs, while the clinical efficacy of relieving pain is not certain.

     

椎体成形与弯角椎体成形治疗骨质疏松性椎体压缩骨折的临床效果与辐射暴露分析

目的:以经典双侧穿刺椎体成形为参照,评价弯角穿刺装置椎体成形的临床效果,分析术中患者及术者受到的辐射暴露,总结防护措施。方法:对2018年3月至2019年9月收治的49例骨质疏松性椎体压缩骨折的临床资料进行回顾性分析,49例患者按手术穿刺方式的不同分为椎体成形组(采用经典双侧穿刺)与弯角椎体成形组(采用弯角穿刺),其中椎体成形组26例,男7例,女19例;年龄(73.25±6.36)岁;胸段2例,胸腰段21例,腰段3例。弯角椎体成形组23例,男6例,女17例;年龄(73.09±6.52)岁;胸段3例,胸腰段19例,腰段1例。记录两组手术时间、骨水泥注入量,采用视觉模拟评分(visual analogue scale,VAS)和改良Oswestry功能障碍指数(Oswestry Disability Index,ODI)评定患者的疼痛程度及腰椎功能,观察术后骨水泥渗漏及并发症,并比较两组患者、术者部分暴露部位受照辐射剂量。结果:49例患者均获随访,时间10~22(14.55±3.83)个月。椎体成形组11例,弯角椎体成形组9例术后发生骨水泥渗漏,两组比较差异无统计学意义。椎体成形组VAS评分术前及术后1 d分别为6.23±0.68,1.69±0.47,改良Oswestry功能障碍指数分别为(72.59±3.25)%,(33.59±2.85)%。弯角椎体成形组VAS评分术前及术后1 d分别为6.46±0.56,1.57±0.49,改良Oswestry功能障碍指数分别为(73.21±3.18)%,(33.17±2.37)%。两组患者术后疼痛程度和腰椎功能均得到明显改善,但组间比较差异无统计学意义。弯角椎体成形组与椎体成形组手术时间分别为(17.27±9.58)min,(23.19±8.56)min,骨水泥注入量分别为(4.91±1.49)ml,(6.58±1.42)ml,手术时间和骨水泥注入量方面弯角椎体成形组更有优势。弯角椎体成形组受福射剂量术者为(0.53±0.05)mSv,患者为(10.64±1.65)mSv,椎体成形组受福射剂量术者为(0.59±0.08)mSv,患者为(13.52±1.81)mSv。弯角椎体成形组患者的受福射剂量明显低于椎体成形组,而两组术者的受福射剂量差异无统计学意义。结论:两种穿刺方式均能达到满意的临床效果,弯角穿刺可更加优化骨水泥的分布,降低患者的辐射剂量。     

经皮椎体成形术骨水泥渗漏对椎体压缩骨折术后邻近椎体骨折的影响及相关性研究

目的 探讨术中骨水泥渗漏情况对经皮椎体成形术(percutaneous vertebroplasty,PVP)术后邻近椎体骨折(adjacent vertebral fracture,AVF)发生率的影响.方法 选择2018年8月-2020年2月于本科收治的单椎体骨质疏松性椎体压缩骨折患者160例,术后随访6个月,明确是否存在AVF,分为AVF组(n=72)及非AVF组(n=88),收集其临床资料以及骨水泥渗漏的相关数据[包括:有无渗漏、渗漏部位(后部、中部、前部)、渗漏方向(上方、下方椎间隙)、骨密度T值、骨水泥与椎间盘相对面积比、骨水泥注入量等指标],评估骨水泥渗漏与AVF发生的相关性.结果 AVF组中45例发生渗漏,非AVF组中发生21例.发生渗漏(r=0.685)、骨密度T值(r=0.495)、下方椎间隙渗漏(r=0.684)、骨水泥注入量(r=0.584)、骨水泥与椎间盘相对面积比(r=0.343),均是AVF的独立危险因素(P<0.05).结论 发生骨水泥渗漏、下方椎间隙渗漏均与AVF的发生显著相关,而且AVF的发生与骨密度、骨水泥注入量、骨水泥与椎间盘相对面积比紧密相关.     

创伤性终板骨折及椎间盘退变对胸腰椎骨折预后的影响

目的探讨创伤性终板骨折及椎间盘退变对胸腰椎骨折预后的影响。方法对98例胸腰椎骨折患者进行手术治疗,依据术前X线片、CT扫描+三维重建诊断分为观察组(有终板骨折,48例)和对照组(无终板骨折,50例)。统计两组末次随访的ODI及VAS评分。结果创伤性终板骨折患者末次随访时的ODI及VAS评分明显高于对照组(P0.05),两组椎间盘退变率比较差异亦有统计学意义(P0.05)。结论创伤性终板骨折会引起椎间盘退变并影响脊柱骨折手术的预后。     

骨质疏松性椎体压缩骨折椎体成形术后骨水泥移位的研究进展

骨质疏松症（osteoporosis,OP）是一种以骨量丢失、骨脆性增加、骨折发生率增加为特征的全身性疾病,该病引起的骨折以骨质疏松性椎体压缩骨折（osteoporosis vertebra compressed fracture,OVCF）最为常见, 我国OVCF的发病率正不断增加,造成了沉重的医疗负担。以经皮椎体成形术（percutaneous vertebroplasty,PVP）和经皮椎体后凸成形术（percutaneous kyphoplasty,PKP）为代表的椎体成形术近20年被越来越多地应用于治疗OVCF。椎体成形术创伤较小,不仅能够减轻、缓解患者疼痛,避免长时间卧床带来的并发症,而且能够有效地恢复椎体强度、稳定骨折,对抗甚至部分逆转椎体骨折后躯体承重向脊柱后柱的转移。但该技术也存在骨水泥渗漏、一过性低血压和意识障碍等风险。近年来,骨水泥移位作为椎体成形术的远期并发症,受到了越来越多的关注。目前常采用骨水泥前缘距椎体前缘距离的变化评估骨水泥位移程度,公认的骨水泥移位的定义为骨水泥位移＞2mm。笔者回顾椎体成形术后骨水泥移位的文献,对骨水泥移位的特点、发生率、潜在机制、危险因素、预防及处理措施等综述如下。     

经单或双侧椎弓根灌注自固化磷酸钙骨水泥椎体成形的效果比较

目的：比较经单或双侧椎弓根将白同化磷酸钙骨水泥（autosetting calcium phosphate cement，ACPC）灌注入骨质疏松性压缩骨折椎体的成形效果。方法：自7具老年新鲜尸体脊柱上取T10～T12或L1～L3连续三节段椎体共10个标本，分别测定初始中间椎体和相邻椎间盘非破坏性载荷下标本前屈、后伸、侧屈和扭转运动时的应力、应变值和轴向刚度。然后在前屈压缩下造成中间椎体骨折。标本随机分成两组，分别经单侧和双侧椎弓根将3ml ACPC注入椎体后再同前测试，并测定中间椎体极限抗压强度和刚度。结果：成形术后中间椎体在非破坏性载荷下标本前屈、后伸和侧屈运动时应力和轴向刚度较初始无明显增加，经单侧和双侧椎弓根灌注组之间也无明显差异，但扭转刚度皆有下降。两组抗压极限强度较初始都有显著性提高。两组相领椎间盘应力和轴向刚度皆无明显变化。结论：经单侧和双侧椎弓根灌注3ml ACPC都能较好恢复骨质疏松性压缩骨折椎体的生物力学性能，对相邻椎间盘的抗压力学性能影响小。     

弯角椎体成形装置的早期疗效评估及对骨水泥分布的影响

[目的]通过比较弯角穿刺PVP、单侧穿刺PVP和双侧穿刺PVP治疗胸腰椎骨质疏松性椎体压缩性骨折(OVCFs)的疗效,探讨弯角穿刺PVP的优势。[方法]将2015年2月~2016年2月75例胸腰椎单椎体OVCFs的患者随机分为3组,分别应用弯角穿刺PVP、单侧穿刺PVP和双侧穿刺PVP。统计并比较3组手术时间、骨水泥注入量、术后3 d的VAS评分、Cobb角恢复率、骨水泥渗漏率和椎体内骨水泥的分布情况。[结果]所有患者均顺利完成手术,未出现严重并发症。3组术后3 d的VAS评分与术前比较差异均有统计学意义(P<0.05);在Cobb角恢复率及骨水泥渗漏率方面,3组间比较差异无统计学意义(P>0.05);在手术时间、骨水泥注入量方面,弯角PVP组与单侧PVP组均小于双侧PVP组且差异有统计学意义(P<0.05);骨水泥理想分布的椎体在弯角PVP组23例(92.00%),在双侧PVP组19例(76.00%),两组比较差异无统计学意义(P>0.001 7),在单侧PVP组3例(12.00%),与前两组比较差异均有统计学意义(P<0.001 7)。[结论]应用弯角椎体成形装置治疗OVCFs短期内可取得满意的临床效果,减少手术时间、骨水泥注入量的同时又优化骨水泥在椎体内的分布,改善术后骨折椎体的稳定性。     

椎间盘退变影响因素研究进展

椎间盘退变是由多种因素影响所致。长期过高和过低的压力负荷均为椎间盘退变的病因之一。近年研究证实软骨终板钙化引起的椎间盘营养供应减少可能是启动椎间盘退变的关键因素。椎间盘老化或营养供应障碍时椎间盘细胞合成一些细胞因子,影响细胞活性和细胞间信息交流,导致细胞凋亡。椎间盘内环境改变后激活潜伏状态的降解酶,使椎间盘基质分解加速,导致椎间盘退变。该文就生物力学、营养、细胞凋亡、细胞因子及降解酶等因素对椎间盘退变的影响及作用机制,作一综述。     

Biomechanical evaluation of kyphoplasty and vertebroplasty with calcium phosphate cement in a simulated osteoporotic compression fracture

 Kyphoplasty and vertebroplasty with polymethylmethacrylate (PMMA) have been used for the treatment of osteoporotic vertebral compression fractures. We performed kyphoplasty and vertebroplasty with α-tricalcium phosphate cement (CPC) and PMMA to compare the biomechanical properties. Thirty osteoporotic vertebrae were harvested from nine embalmed cadavers. We randomized the vertebrae into four treatment groups: (1) kyphoplasty with CPC; (2) kyphoplasty with PMMA; (3) vertebroplasty with CPC; and (4) vertebroplasty with PMMA. Prior to injecting the cement, all vertebrae were compressed to determine their initial strength and stiffness. They were then recompressed to determine their augmented strength and stiffness. Although the augmented strength was greater than the initial strength in all groups, there was no significant difference between the two bone cements for either kyphoplasty or vertebroplasty. The augmented stiffness was significantly less than the initial stiffness in the kyphoplasty groups, but the difference between the two cements did not reach significance. In the vertebroplasty groups, the augmented stiffness was not significantly different from the initial stiffness. There was no significant difference between the two bone cements for either procedure when cement volume and restoration of anterior height were assessed. We concluded that kyphoplasty and vertebroplasty with CPC were viable treatment alternatives to PMMA for osteoporotic vertebral compression fractures. Received: July 18, 2002 / Accepted: November 6, 2002 Offprint requests to: S. Tomita     

Lumbar disc degeneration: epidemiology and genetics

Research conducted over the past decade has led to a dramatic shift in the understanding of disc degeneration and its etiology. Previously, heavy physical loading-often associated with occupation-was the main suspected risk factor for disc degeneration, which was commonly viewed as a wear-and-tear phenomenon exacerbated by the precarious nutritional status of the disc. However, results of studies on twins suggest that physical loading specific to occupation and sport plays a relatively minor role in disc degeneration. Recent research indicates that heredity has a dominant role in disc degeneration, which would explain the variance of up to 74% seen in adult populations that have been studied to date. Since 1998, genetic influences have been confirmed by the identification of several gene forms associated with disc degeneration. This research is paving the way for a better understanding of the biologic mechanisms through which disc degeneration occurs, including specific interactions between genes and environment. Research into disc degeneration and genetics has become more limited by phenotypes or definitions and measures of disc degeneration than by DNA analysis. Standardized, universally accepted definitions of disc degeneration are lacking, in part due to limited knowledge of the process. The measurements that are selected depend on the method used to evaluate the disc and are often qualitative ordinal rating scales, lacking in precision. Although it is generally agreed that disc degeneration is common, the prevalence of specific findings is unclear. A review of the epidemiology of disc degeneration reveals wide-ranging prevalence estimates for various signs of disc degeneration in samples of the general population and in patients with back symptoms. The extreme variations in prevalence rates are likely largely due to inconsistencies in the definitions and measurements of disc degeneration. Such inconsistencies and inaccuracies impede epidemiologic research on disc degeneration.     

炎症在腰椎间盘退变、突出、吸收发病机制中的作用

腰椎间盘退变、突出是下腰痛的主要原因,炎症与腰椎间盘退变及下腰痛密切相关.病理性退变的椎间盘细胞出现炎症介质异常表达,炎症介质诱导激活基质金属蛋白酶,加剧椎间盘退变.纤维环破裂、髓核组织暴露于硬膜外,激发急性创伤炎症反应,合成、分泌大量炎症介质,引起神经根炎,导致坐骨神经痛,同时炎症反应促使腰椎间盘突出组织吸收.该文就近年来有关炎症与腰椎间盘病变关系的研究进展作一综述.