纤维环缝合对腰椎稳定性及椎间盘内压力影响的研究

[目的]通过生物力学测试研究纤维环缝合对腰椎稳定性以及椎间盘压力的影响。[方法]选取10具L4/5的小牛脊柱标本在纤维环完整、切开以及缝合3种状态下进行生物力学测试,观察标本在屈伸、侧弯、旋转时的活动度(ROM)、中性区(NZ)的变化以及椎间盘内压力的变化。[结果]纤维环切开后,在前屈、左右侧弯的ROM和NZ值较完整组显著增加(P<0.05),纤维环缝合后,上述方向上的ROM和NZ值较切开组显著下降(P<0.05),而与完整组无明显差异;3组在后伸、左右旋转的ROM和NZ值均无明显差异。完整组、切开组和缝合组的泄露压力分别为(5.0±0.0)MPa、(0.5±0.5)MPa和(1.7±0.8)MPa,纤维环缝合组的泄露压力较切开组增加,但仍小于完整组。[结论]腰椎纤维环切开术后缝合纤维环能部分恢复椎间盘内压力和腰椎节段运动的稳定性。     

纤维环切口方式对椎间盘生物力学强度影响的动物实验研究

目的探讨不同切口方式处理椎间盘纤维环对髓核摘除术后山羊椎间盘生物力学强度的影响。方法取30只成年健康山羊,雌雄各半,随机分为A、B、C 3组(n=10)。3组行L_(3、4)及L_(4、5)椎间盘髓核摘除术中,切开纤维环时,分别采用工作套筒刺入(A组)、圆形切口切开(B组)、方形切口切开(C组)。记录并比较3组山羊体质量、雌雄比例、年龄、术中出血量及切口愈合时间;术后观察各组山羊存活及切口愈合情况。术后24周时处死山羊,MRI检查髓核信号强度;游标卡尺测量L_(3、4)及L_(4、5)椎间盘高度,取均值,并计算手术前后高度丢失程度;生物力学测定L_(3、4)诱发椎间盘突出的压力值及椎间盘承受的最大压力值;大体、组织学染色观察L_(4、5)椎间盘纤维环的修复效果。结果 3组山羊体质量、雌雄比例、年龄、术中出血量、切口愈合时间比较差异均无统计学意义(P0.05),具有可比性。3组山羊均存活至实验完成。MRI检查3组椎间盘均可见退变现象,信号均降低;根据改良Thompson分级法,A组椎间盘退变程度高于B、C组(P0.05),B、C组间比较差异无统计学意义(P0.05)。3组术前椎间隙高度比较差异无统计学意义(P0.05);但术后24周A组椎间隙高度高于B、C组,其丢失程度低于B、C组差异均有统计学意义(P0.05)。A组诱发椎间盘突出的压力值及椎间盘承受的最大压力值均显著大于B、C组(P0.05),B、C组间差异无统计学意义(P0.05)。HE及Masson染色示:A组纤维环连续性良好层次较清淅;B、C组切开处可见纤维环连续性破坏,瘢痕组织填充明显。结论椎间盘髓核摘除术中,采用工作套筒切开纤维环对纤维环结构破坏小,对维持椎间盘生物力学强度及术后纤维环修复起到积极作用。     

基质细胞衍生因子-1在人正常和退变椎间盘中的表达、分布及意义

目的:比较人正常和退变椎间盘髓核中央区、髓核与纤维环交界区、纤维环外层、纤维环内层及软骨终板5个相邻部位的基质细胞衍生因子-1 (SDF-1)的表达情况,探讨退变椎间盘SDF-1的表达在上述五个相邻部位是否具有差异.方法:获取20例腰椎间盘突出症患者的椎间盘(L4/5,病理证实为退变椎间盘组织),并纳入退变组;7例急性腰椎爆裂骨折患者的椎间盘(L3/4)及3例脊柱侧凸患者的椎间盘(L2/3,病理证实为正常椎间盘组织),纳入正常组.HE染色观察两组椎间盘的组织学结构,免疫组织化学、Western-blot、rt-PCR检测椎间盘髓核中央区、髓核与纤维环交界区、纤维环内层、纤维环外层及软骨终板5个部位的SDF-1表达情况及分布,并将退变椎间盘上述5个部位的SDF-1免疫组化积分光密度值与供者年龄、椎间盘Thompson分级作相关分析.结果:正常组的上述5个部位SDF-1免疫组化积分光密度值分别为420.87±89.93、407.80±100.76、380.02±85.05、342.89±63.76、344.06±88.97;Western-blot灰度比值分别为0.08±0.03、0.08±0.05、0.07±0.04、0.05±0.03、0.05±0.02;rt-PCR灰度比值分别为0.22±0.06、0.22±0.05、0.20±0.04、0.20±0.04、0.20±0.04.退变组上述5个部位SDF-1免疫组化积分光密度值分别为7355.13±2271.74、5959.58±2436.23、5397.49±3044.80、1605.44±825.31、361.91±104.22; Western-blot灰度比值分别为0.55±0.29、0.52±0.28、0.42±0.18、0.21±0.12、0.06±0.04;rt-PCR灰度比值分别为0.75±0.30、0.71±0.26、0.55±0.22、0.36±0.17、0.22±0.13.退变椎间盘5个部位的SDF-1表达均高于正常组(P＜0.05),且SDF-1表达量髓核中央区＞纤维环内层＞纤维环外层＞软骨终板,差异有统计学意义(P＜0.05),而髓核中央区和髓核与纤维环交界区比较无统计学差异(P＞0.05);退变椎间盘上述5个部位的SDF-1表达与椎间盘Thompson分级、年龄呈正相关性(P＜0.05).结论:SDF-1广泛表达于退变和正常的椎间盘中,其表达在退变椎间盘中上述5个相邻部位存在差异.     

椎间盘纤维环中糖胺多糖的实验研究

目的　研究正常和退变腰椎间盘纤维环中糖胺多糖 (GAG)含量及其主要成份百分组成 ,探讨椎间盘退变的发生机理。方法　对 34个正常纤维环和 35个椎间盘突出症纤维环标本中GAG含量进行测定 ,并用醋酸纤维素膜电泳和光密度扫描的方法对GAG主要成份百分组成进行测定。结果　正常纤维环GAG含量为 4 17± 0 94g/10 0 g ,退变纤维环GAG含量为 3 5 7± 0 98g/10 0g ,低于正常组 (P <0 0 5 ) ;退变组GAG中硫酸软骨素 (CS)百分值低于正常组 (P <0 0 5 ) ;而其透明质酸 (HA)和硫酸角质 (KS)高于正常组 (P <0 0 5 )。结论　椎间盘纤维环中GAG含量下降 ,是引起纤维环胶原纤维稳定性降低 ,影响纤维环板层滑动 ,导致椎间盘退变、突出症发生的重要原因之一。退变纤维环GAG含量下降由其主要成分CS含量下降所致     

L5/S1和骶髂关节对腰-髂固定稳定性影响的生物力学分析

目的:探讨L5/S1和骶髂关节对腰-髂固定稳定性的影响,为腰-髂稳定性理想重建提供生物力学依据.方法:7具成年新鲜尸体L2-骨盆标本,先行L3～L5椎弓根螺钉固定,并将此结构定义为腰-髂部稳定初始状态.初始状态测试后,在同一标本上实施连续性操作如下:使用髂骨钉的L3-髂骨固定(A组)、L5/S1双侧关节突关节切除(B组)、L5/S1椎间盘切除(C组)、左侧骶髂关节切除(D组).在MTS材料实验机上,给标本头侧分别施加600N轴向压缩和7Nm轴向扭转载荷,计算并比较各组结构压缩和扭转刚度.结果:初始状态组的压缩刚度值为(332±103)N/mm,A～D组腰-髂固定结构的压缩刚度分别为初始状态组的(122±15.5)％、(118.3±10.5)％、(81.1±7.7)％和(59.2±8.6)％.A和B组间无显著性差异(P＞0.05),两组的压缩刚度均显著高于初始状态组(P＜0.05);C组和D组的压缩刚度均显著低于A、B组及初始状态组(P＜0.05),C组和D组间的差异也具有显著性(P＜0.05).初始状态组的扭转刚度值为(2.47±0.88)Nm/deg,A～D组固定结构的扭转刚度分别为初始状态组的(128±14.3)％、(120±12.6)％、(78.4±13.2)％和(62.9±11.3)％,A组和B组获得同等的扭转刚度(P＞0.05),而且此两组的扭转刚度均显著高于初始状态、C组和D组(P＜0.05),C、D组和初始状态三组彼此间的差异均具有显著性(P＜0.05).结论:L5/S1椎间盘切除和单侧骶髂关节切除均显著降低腰-髂固定结构的稳定性,在腰-髂稳定性重建中,获得脊柱前方支撑和恢复骨盆环完整性是提高腰-髂固定结构稳定性的关键.     

纤维环穿刺抽吸法和纤维环切开法建立兔椎间盘退变模型的比较

[目的]通过纤维环穿刺抽吸法和纤维环切开法建立兔椎间盘退变模型,分析此两种方法的可行性及特点.[方法]取10个月龄健康日本大耳白兔24只,随机分为2组,其中A组为纤维环穿刺抽吸组,利用18G穿刺针分别在兔L3、4、L4、5、L5、6椎间盘刺入并抽吸髓核8～ 12 mg;B组为纤维环切开组,利用手术刀分别在兔L3、4、L4、5、L5、6椎间盘纤维环上做水平位切口;造模完毕,两组兔分别于术后4、8、12、16周进行MRI检查,病理组织学观察和免疫组化染色观察.[结果]A、B两组退变椎间盘MRI T2加权像信号随时间延长呈现持续减弱趋势,术后4、8周纤维环穿刺组T2加权像信号强度评分较纤维环切开组低(P＜0.05),组织学观察发现造模组髓核细胞逐渐减少;免疫组化染色观察Ⅱ型胶原和蛋白聚糖表达含量随时间延长逐渐降低,且B组含量明显低于A组.[结论]两种方法均能建立兔椎间盘退变模型,但纤维环切开法椎间盘的退变程度较纤维环穿刺法出现较早且较为剧烈.     

渗透压负荷对兔椎间盘器官培养模型的影响

目的:建立一种可用于体外研究椎间盘退变的椎间盘器官培养模型,探讨渗透压负荷对模型椎间盘细胞活力和代谢的影响.方法:4～6月龄新西兰大白兔10只,均分为两组,处死后立即手术切取胸腰段椎间盘,每只9个,分别在等渗(300mOsm/kg,等渗组)或高渗(410mOsm/kg,高渗组)培养基中进行整体器官培养,在培养前和培养后第7、14、21、28天,利用Mitotracker Green荧光探针、组织化学和生物化学方法评估两组椎间盘髓核细胞的活力、结构的完整性以及蛋白多糖含量的变化.结果:取材后培养前椎间盘髓核细胞的荧光强度为11503±402,在体外培养过程中,高渗组第14天荧光强度为9202±907,与培养前比较差异有显著性意义(P＜0.05),第7、21和28天分别为10504±710、10860±711、10713±953,与培养前相比较无显著性差异(P＞0.05);等渗组第7、14、21、28天分别为11350±351、11207±385、10914±300、10862±229,与培养前比较无显著性差异(P＞0.05);两组在第7、21和28天时无显著性意义(P＞0.05).在培养过程中,两组椎间盘髓核和纤维环的组织结构能够基本保持完整,髓核蛋白多糖含量在培养第7天高渗组和等渗组分别为3.33±0.28m/100mg和2.83±0.25m/100mg,均较培养前(5.03±0.37m/100mg)明显降低(P＜0.01),第14、21、28天时与第7天相比下降不明显(P＞0.05).两组相同时间点的差异无显著性意义(P＞0.05).结论:椎间盘器官培养模型可以在等渗或高渗环境中有效维持兔椎间盘结构的完整性和髓核细胞的活力至少4周.     

兔髓核组织中BNIP3表达与椎间盘退变的关系

目的:探讨兔椎间盘髓核组织中BNIP3表达量与椎间盘退变的相关性。方法:健康1月龄新西兰白兔24只,随机分为4组,每组6只。在每只动物的L4/5、L5/6和L6/7椎间盘进行纤维环穿刺术,建立椎间盘退变模型,作为实验椎间盘;穿刺椎间盘近端3个椎间盘(L1/2、L2/3、L3/4)作为正常对照椎间盘。分别于术后即刻、2、4、8周对椎间盘进行MRI及组织学评分,应用Real-time PCR定量检测髓核组织BNIP3 mRNA表达,免疫组织化学染色半定量髓核组织BNIP3表达,同时分析同一椎间盘BNIP3表达与MRI评分、组织学评分之间的相关性,并与正常椎间盘进行对照。结果:正常及手术后即刻实验椎间盘在MRI T2加权像上呈高密度,评分为1.0±0.0;手术后2周实验椎间盘信号呈不均一的高密度,评分为2.9±0.4;手术后4周实验椎间盘信号呈不均一中低密度,评分4.2±0.3;手术后8周实验椎间盘信号呈低密度,评分4.9±0.1,各时间点MRI评分比较有显著性差异(P<0.05)。组织学染色显示正常及手术后即刻椎间盘结构整齐,髓核与纤维环交界清晰,组织学评分4.0±0.0;手术后2周实验椎间盘纤维环出现小裂隙,髓核与纤维环交界轻度不清,组织学评分7.5±0.2;手术后4周实验椎间盘纤维环出现较大裂隙,髓核与纤维环交界中度不清,组织学评分10.0±1.0;手术后8周实验椎间盘正常结构丧失,髓核组织纤维化,组织学评分11.8±0.2,各时间点间组织学评分比较有显著性差异(P<0.05)。手术后即刻、2周、4周及8周实验椎间盘BNIP3 mRNA表达是正常组的1.0±0.3倍、2.0±0.1倍、2.8±0.3倍和4.2±0.2倍,与椎间盘MRI退变评分呈显著性正相关(r=0.92,P<0.01)。正常及手术后即刻实验椎间盘髓核组织BNIP3灰度值分别为55.3±6.2和60.7±4.4;而手术后2周、4周及8周实验椎间盘分别为150.4±13.4、176.0±35.1和173.6±7.9,其灰度值与椎间盘组织学评分呈显著性正相关(r=0.92,P<0.01)。结论:兔椎间盘髓核组织中BNIP3 mRNA表达量与椎间盘退变相关,BNIP3表达上调可能在椎间盘退变过程中发挥了重要作用。     

伞状支撑骨移植术治疗股骨头坏死的生物力学研究

目的 观察伞状支撑骨移植术治疗股骨头坏死的生物力学变化.方法 应用伞状支撑骨移植术(A组)治疗山羊股骨头坏死模型,并通过生物力学检测与单纯股方肌骨柱移植术组(B组)、骨髓间充质干细胞和松质骨移植术组(C组)进行对照研究(每组均14只).结果 术后3个月A组手术侧股骨头软骨下骨、松质骨的最大压强和弹性模量为:(77.43±2.65)、(120.60±4.18)MPa;(46.63±1.32)、(81.74±3.96)MPa.高于B组、C组(P＜0.05),与正常侧比较差异无统计学意义(P＞0.05).结论 伞状支撑骨移植术能有效恢复股骨头的生物力学强度,防止塌陷.     

椎间盘的组织工程学

人体椎间盘由纤维环、髓核、软骨终板3部分组成,它柔韧而牢固,不仅具有稳定脊柱、传递载荷、吸收震荡、分散应力的功能,而且还是脊柱灵活运动的结构基础.椎间盘的完整性对维持脊柱的正常生理功能具有重要意义.然而临床工作中,却常常因各种原因不得不将椎间盘切除,如许多严重的椎间盘突出症患者,必须行髓核摘除才能缓解其临床症状.实验研究表明椎间盘切除以后必然产生椎间隙变窄,使腰椎前部应力下降,后部应力上升,导致脊柱生物力学功能紊乱,产生腰椎不稳和邻近节段的退变加速.许多学者尝试采用各种各样的人工椎间盘替代切除或受损的椎间盘,但由于椎间盘的生物力学结构的复杂性是任何一种人工椎间盘难以替代的,大多数人工椎间盘的远期效果难以令人满意.近年来随着组织工程学的蓬勃发展和在骨与关节软骨缺损修复中的成功应用,人们开始尝试用组织工程学的方法重建受损或切除的椎间盘,并已取得了一定的成绩,本文就椎间盘组织工程学方面的研究进展做一综述.     

山羊腰椎间盘损伤后P物质免疫染色阳性神经纤维的分布

目的 研究山羊椎间盘损伤后的组织学改变及P物质(substance P,SP)免疫染色阳性神经纤维在损伤纤维中的分布.方法 15只山羊,用直径1.2 mm的穿刺针刀刺伤L5/L6椎间盘前纤维环全层和L6/L7后部纤维环内侧,以L4/L5椎间盘作为完整对照椎间盘.分别于损伤后3周、3个月、6个月随机处死5只山羊.观察实验...     

Histological changes in intervertebral discs after smoking and cessation: experimental study using a rat passive smoking model

Background Passive smoking has been reported to induce intervertebral disc degeneration in rats, and the objective of the present study was to histologically investigate changes in smoking-induced intervertebral disc degeneration after cessation of smoking. Methods Four-week-old rats were subjected to passive smoking for 8 weeks in a smoking box [20 cigarettes a day: one cigarette an hour (inhaled over 3 minutes and followed by ventilation with room air for 5 minutes)] to induce intervertebral disc degeneration. Smoke-free periods of different lengths were then established, and intervertebral discs were histologically analyzed. Results Immediately after 8 weeks of passive smoking, intervertebral discs exhibited cracks, tears, and misalignment of the annulus fibrosus, and increased fibrous tissue was seen in the nucleus pulposus. In addition, the level of interleukin-1β in intervertebral discs was higher in the smoking group than in the non-smoking group. After cessation, progression of degeneration ceased, and the matrix of the nucleus pulposus and annulus fibrosus exhibited increased fibrous connective tissue and proteoglycan. However, there were no changes in annulus fibrosus misalignment. Interleukin-1β levels also remained significantly elevated after 8 weeks of cessation. Conclusions While the annulus fibrosus degeneration caused by smoking was partially irreversible after cessation of smoking, the amount of mucin (proteoglycan) in the nucleus pulposus and annulus fibrosus tended to increase after cessation, thus suggesting the possibility that smoking-induced intervertebral disc degeneration can be repaired to some degree by cessation of smoking.     

Effect of anular repair on the healing strength of the intervertebral disc: a sheep model

STUDY DESIGN: The intervertebral disc, in a sheep model, was used to assess the effect of directly repairing three different anular incisions on the subsequent healing strength of the intervertebral disc. OBJECTIVES: To assess whether directly repairing an anular defect, made at the time of lumbar discectomy, could influence the healing rate and strength of the anulus fibrosus. METHODS: Twenty-four sheep underwent a retroperitoneal approach to five lumbar disc levels. An anular incision, followed by partial discectomy was done at each exposed level. Anular incisions used in this study consisted of 1) a straight transverse slit, 2) a cruciate incision, and 3) a window or box excision. Healing strength was measured at three time intervals: 2 weeks, 4 weeks, and 6 weeks. Each anular incision type was performed on 30 lumbar discs, 10 discs in each time interval. Five discs in each time interval underwent direct repair, and five discs were left unrepaired to heal as controls. The sheep were killed at 2, 4, and 6 weeks after surgery. The lumbar spines were removed en bloc, and the intervertebral discs were subjected to pressure-volume testing to assess the anular strength of repaired versus unrepaired disc injuries at each time interval. RESULTS: Statistical analysis was performed to evaluate the effects of healing time, incision technique, and repair on the pressure-volume characteristics of the involved discs. Pressure-volume testing showed trends of stronger healing for repaired discs, but at no time interval was any significant difference found between repaired and nonrepaired anular strength. Of the nonrepaired discs, the box incision was only 40 to 50% as strong as the slit or cruciate incised discs during early healing. CONCLUSION: Direct repair of anular incisions in the lumbar spine does not significantly alter the healing strength of the intervertebral disc after lumbar discectomy.     

An observation of ruptured annulus fibrosus in lumbar discs.

To observe anatomical or pathological changes in lumbar intervertebral discs, discography and computed tomography-discography (CTD) were performed on fresh human cadavers. The results of discograms and CTD were compared with histological findings of cross sections of discs. Preoperative CTD of lumbar disc herniation was investigated based on these results. Ruptures of the annulus fibrosus were divided into two categories: circumferential rupture and radial rupture. In CTD images of fresh human cadavers, most images of rupture of the annulus fibrosus showed anterior to lateral circumferential rupture. As disc degeneration progressed, circumferential rupture tended to coexist with radial rupture in many cases. In CTD cases of lumbar disc herniation, most images of ruptures of the annulus fibrosus showed a posterior radial rupture, which was the route for herniated nucleus. The greater the degree of degeneration, the more the images tended to show radial ruptures coexisting with circumferential ruptures.     

两种骨水泥渗漏对椎间盘影响的实验研究

目的 探讨椎体成形术时骨水泥渗漏是否会引起椎间盘退变，以及椎间盘退变程度与骨水泥类型是否相关。方法 选用8只成年家犬，以每只犬L2-3、L3-4、L4-5椎间盘为实验对象，随机分为对照组、聚甲基丙烯酸甲酯（polymethylmethacrylate，PMMA）与磷酸钙骨水泥（calcium phosphate cement，CPC）3组。对照组仅行椎间盘穿刺，不注入任何物质，PMMA组及CPC组均各向椎间盘注入0．1ml骨水泥。术前及术后24周摄正、侧位X线片，计算椎间盘高度指数百分数（disc height index percentage，DHIP）。术后24周行MR检查，计算MRI指数。组织学检查参照Masuda标准对椎间盘退变程度评分并分析。结果 术后24周X线片显示对照组椎间隙无狭窄，病理学检查未见椎间盘退变。PMMA、CPC组椎间盘MRI显示：椎间隙有狭窄，R加权像髓核信号不同程度降低且不均一，其相对高信号区面积减小，髓核形态不规则，纤维环与髓核界限不清。组织学检查显示髓核细胞数量不同程度减少，空泡变小。髓核的细胞外基质不同程度压缩，纤维环断裂或扭转。3组DHIP、MRI指数、组织学评分的差异均有统计学意义（P〈0.01）。结论 PMMA、CPC注入椎间盘会导致椎间盘退变，PMMA所致椎间盘退变较CPC更为严重.     

椎间盘源性下腰痛的发病机制

目的探讨椎间盘源性下腰痛的发病机制。方法收集腰椎后路切除的17例椎间盘源性下腰痛患者的19个经腰椎间盘造影术证实的疼痛腰椎间盘;同时收集12个在MRI T2加权像上信号强度明显减弱、无腰痛症状的生理老化椎间盘和10个正常对照椎间盘,行组织学检查和P物质、神经丝蛋白和血管活性肠肽的免疫组织化学染色检查。结果椎间盘源性下腰痛患者的疼痛椎间盘在组织学上的显著特征表现为,一条从髓核至纤维环外层的血管化肉芽组织条带区,其间伴有1个或多个裂隙;肉芽组织条带区与椎间盘造影术后CT上显示的纤维环裂隙一致,肉芽组织之外的纤维环结构基本正常。生理老化椎间盘和正常对照椎间盘表现为与年龄相关的改变。免疫组织化学染色显示,疼痛椎间盘中P物质、神经丝蛋白和血管活性肠肽3种神经肽阳性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;神经纤维主要沿伴有裂隙的肉芽组织条带区分布;疼痛椎间盘髓核中可见P物质和神经丝蛋白的阳性神经纤维分布。结论椎间盘后方神经分布广泛的肉芽组织条带区是椎间盘造影术疼痛和椎间盘源性下腰痛的起源部位。肉芽组织条带可能起源于椎间盘的创伤修复过程。生理老化椎间盘和疼痛椎间盘的差异是后者形成组织学上的肉芽组织条带区。     

退变颈椎间盘中IL-17表达与分布的研究

目的 观察退变颈椎间盘中自细胞介素-17(IL-17)的表达与分布,并探讨其与颈椎间盘退变发生发展的关系.方法 实时荧光相对定量PCR(RQ-PCR)检测30例退变颈椎间盘及10例正常对照椎间盘中IL-1β、IL-17、肿瘤坏死因子-α(TNF-α)和孤核受体(retinoid-related orphan re-ce...     

Histological study on chemonucleolysis with special reference to the relationship between the dose of chymopapain and disc regeneration

The present study on chemonucleolysis was conducted to determine the influence of chymopapain dose level and patient age on the degree and mode of the response and regeneration of the intervertebral disc. Chymopapain at various doses was injected into the intervertebral discs of young (8-week-old) and mature (20-week-old) rabbits respectively for a histological study. In rabbits undergoing high dose injection, not only the nucleus pulposus but also the inner layer of the annulus fibrosus was digested. Regeneration hardly occurred, and only a slight amount of scar tissue appeared in many animals. At lower dose, the annulus fibrosus remained intact and the posterior inner layer of the annulus fibrosus mainly proliferated toward the anterior portion of the disc, filled the space of digested nucleus pulposus, and restored disc height. This regeneration process was not thought to be specific to the damages caused by chymopapain but rather a common response of injured intervertebral discs.     

T2* mapping of ovine intervertebral discs: Normative data for cervical and lumbar spine

To obtain T2* values in histologically evaluated healthy ovine intervertebral discs of the cervical and lumbar spine. Intervertebral discs of nine sheep and nine lambs underwent histological assessment with the modified Boos score for grading of disc degeneration. Discs with a score <10 points (maximum = 40 points) underwent T2* mapping (n = 64). Mid‐sagittal T2* values were obtained in five regions: Anterior annulus fibrosus, anterior nucleus pulposus, central nucleus pulposus, posterior nucleus pulposus, and posterior annulus fibrosus. We noted a zonal T2* distribution with high values in the central nucleus and low T2* values in the anterior and posterior annulus fibrosus. The T2* values were higher in lamb than in sheep IVDs for both cervical and lumbar spine (p < 0.001). The T2* values were also higher in the cervical than in the lumbar spine (p = 0.029 for sheep and p < 0.001 for lamb IVDs). The T2* values obtained in these ovine intervertebral discs can serve as baseline values for future T2* measurements both in health and disease. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:717–724, 2016.